WorldWideScience

Sample records for mixed methanotrophic culture

  1. [Culturable psychrotolerant methanotrophic bacteria in landfill cover soil].

    Science.gov (United States)

    Kallistova, A Iu; Montonen, L; Jurgens, G; Munster, U; Kevbrina, M V; Nozhevnikova, A N

    2014-01-01

    Methanotrophs closely related to psychrotolerant members of the genera Methylobacter and Methylocella were identified in cultures enriched at 10@C from landfill cover soil samples collected in the period from April to November. Mesophilic methanotrophs of the genera Methylobacter and Methylosinus were found in cultures enriched at 20 degrees C from the same cover soil samples. A thermotolerant methanotroph related to Methylocaldum gracile was identified in the culture enriched at 40 degrees C from a sample collected in May (the temperature of the cover soil was 11.5-12.5 degrees C). In addition to methanotrophs, methylobacteria of the genera Methylotenera and Methylovorus and members of the genera Verrucomicrobium, Pseudomonas, Pseudoxanthomonas, Dokdonella, Candidatus Protochlamydia, and Thiorhodospira were also identified in the enrichment cultures. A methanotroph closely related to the psychrotolerant species Methylobacter tundripaludum (98% sequence identity of 16S r-RNA genes with the type strain SV96(T)) was isolated in pure culture. The introduction of a mixture of the methanotrophic enrichments, grown at 15 degrees C, into the landfill cover soil resulted in a decrease in methane emission from the landfill surface in autumn (October, November). The inoculum used was demonstrated to contain methanotrophs closely related to Methylobacter tundripaludum SV96.

  2. Culture scale-up and immobilisation of a mixed methanotrophic consortium for methane remediation in pilot-scale bio-filters.

    Science.gov (United States)

    Karthikeyan, Obulisamy Parthiba; Saravanan, Nadarajan; Cirés, Samuel; Alvarez-Roa, Carlos; Razaghi, Ali; Chidambarampadmavathy, Karthigeyan; Velu, Chinnathambi; Subashchandrabose, Gobalakrishnan; Heimann, Kirsten

    2017-02-01

    Robust methanotrophic consortia for methane (CH 4 ) remediation and by-product development are presently not readily available for industrial use. In this study, a mixed methanotrophic consortium (MMC), sequentially enriched from a marine sediment, was assessed for CH 4 removal efficiency and potential biomass-generated by-product development. Suitable packing material for bio-filters to support MMC biofilm establishment and growth was also evaluated. The enriched MMC removed ∼7-13% CH 4 under a very high gas flow rate (2.5 L min -1 ; 20-25% CH 4 ) in continuous-stirred tank reactors (∼10 L working volume) and the biomass contained long-chain fatty acids (i.e. C 16 and C 18 ). Cultivation of the MMC on plastic bio-balls abated ∼95-97% CH 4 in pilot-scale non-sterile outdoor-operated bio-filters (0.1 L min -1 ; 1% CH 4 ). Contamination by cyanobacteria had beneficial effects on treating low-level CH 4 , by providing additional oxygen for methane oxidation by MMC, suggesting that the co-cultivation of MMC with cyanobacterial mats does not interfere with and may actually be beneficial for remediation of CH 4 and CO 2 at industrial scale.

  3. Responses of mixed methanotrophic consortia to variable Cu2+/Fe2+ ratios.

    Science.gov (United States)

    Chidambarampadmavathy, Karthigeyan; Karthikeyan, Obulisamy Parthiba; Huerlimann, Roger; Maes, Gregory E; Heimann, Kirsten

    2017-07-15

    Methane mitigation in landfill top cover soils is mediated by methanotrophs whose optimal methane (CH 4 ) oxidation capacity is governed by environmental and complex microbial community interactions. Optimization of CH 4 remediating bio-filters need to take microbial responses into account. Divalent copper (Cu 2+ ) and iron (Fe 2+ ) are present in landfills at variable ratios and play a vital role in methane oxidation capacity and growth of methanotrophs. This study, as a first of its kind, therefore quantified effects of variable Cu 2+ and Fe 2+ (5:5, 5:25 and 5:50 μM) ratios on mixed methanotrophic communities enriched from landfill top cover (LB) and compost soils (CB). CH 4 oxidation capacity, CH 4 removal efficiencies, fatty acids content/profiles and polyhydroxybutyrate (PHB; a biopolymer) contents were also analysed to quantify performance and potential co-product development. Mixed methanotroph cultures were raised in 10 L continuous stirred tank reactors (CSTRs, Bioflo ® & Celligen ® 310 Fermentor/Bioreactor; John Morris Scientific, Chatswood, NSW, Australia). Community structure was determined by amplifying the V3-V4 region of 16s rRNA gene. Community structure and, consequently, fatty acid-profiles changed significantly with increasing Cu 2+ /Fe 2+ ratios, and responses were different for LB and CB. Effects on methane oxidation capacities and PHB content were similar in the LB- and CB-CSTR, decreasing with increasing Cu 2+ /Fe 2+ ratios, while biomass growth was unaffected. In general, high Fe 2+ concentration favored growth of the type -II methanotroph Methylosinus in the CB-CSTR, but methanotroph abundances decreased in the LB-CSTR. Increase in Cu 2+ /Fe 2+ ratio increased the growth of Sphingopyxis in both systems, while Azospirllum was co-dominant in the LB- but absent in the CB-CSTR. After 13 days, methane oxidation capacities and PHB content decreased by ∼50% and more in response to increasing Fe 2+ concentrations. Although methanotroph

  4. Enrichments of methanotrophic-heterotrophic cultures with high poly-β-hydroxybutyrate (PHB) accumulation capacities.

    Science.gov (United States)

    Zhang, Tingting; Wang, Xiaowei; Zhou, Jiti; Zhang, Yu

    2018-03-01

    Methanotrophic-heterotrophic communities were selectively enriched from sewage sludge to obtain a mixed culture with high levels of poly-β-hydroxybutyrate (PHB) accumulation capacity from methane. Methane was used as the carbon source, N 2 as sole nitrogen source, and oxygen and Cu content were varied. Copper proved essential for PHB synthesis. All cultures enriched with Cu could accumulate high content of PHB (43.2%-45.9%), while only small amounts of PHB were accumulated by cultures enriched without Cu (11.9%-17.5%). Batch assays revealed that communities grown with Cu and a higher O 2 content synthesized more PHB, which had a wider optimal CH 4 :O 2 range and produced a high PHB content (48.7%) even though in the presence of N 2 . In all methanotrophic-heterotrophic communities, both methanotrophic and heterotrophic populations showed the ability to accumulate PHB. Although methane was added as the sole carbon source, heterotrophs dominated with abundances between 77.2% and 85.6%. All methanotrophs detected belonged to type II genera, which formed stable communities with heterotrophs of different PHB production capacities. Copyright © 2017. Published by Elsevier B.V.

  5. Enrichment culture and identification of endophytic methanotrophs isolated from peatland plants.

    Science.gov (United States)

    Stępniewska, Zofia; Goraj, Weronika; Kuźniar, Agnieszka; Łopacka, Natalia; Małysza, Magdalena

    2017-09-01

    Aerobic methane-oxidizing bacteria (MOB) are an environmentally significant group of microorganisms due to their role in the global carbon cycle. Research conducted over the past few decades has increased the interest in discovering novel genera of methane-degrading bacteria, which efficiently utilize methane and decrease the global warming effect. Moreover, methanotrophs have more promising applications in environmental bioengineering, biotechnology, and pharmacy. The investigations were undertaken to recognize the variety of endophytic methanotrophic bacteria associated with Carex nigra, Vaccinium oxycoccus, and Eriophorum vaginatum originating from Moszne peatland (East Poland). Methanotrophic bacteria were isolated from plants by adding sterile fragments of different parts of plants (roots and stems) to agar mineral medium (nitrate mineral salts (NMS)) and incubated at different methane values (1-20% CH4). Single colonies were streaked on new NMS agar media and, after incubation, transferred to liquid NMS medium. Bacterial growth dynamics in the culture solution was studied by optical density-OD600 and methane consumption. Changes in the methane concentration during incubation were controlled by the gas chromatography technique. Characterization of methanotrophs was made by fluorescence in situ hybridization (FISH) with Mg705 and Mg84 for type I methanotrophs and Ma450 for type II methanotrophs. Identification of endophytes was performed after 16S ribosomal RNA (rRNA) and mmoX gene amplification. Our study confirmed the presence of both types of methanotrophic bacteria (types I and II) with the predominance of type I methanotrophs. Among cultivable methanotrophs, there were different strains of the genus Methylomonas and Methylosinus. Furthermore, we determined the potential of the examined bacteria for methane oxidation, which ranged from 0.463 ± 0.067 to 5.928 ± 0.169 μmol/L CH4/mL/day.

  6. Nutrient recovery from industrial wastewater as single cell protein by a co-culture of green microalgae and methanotrophs

    DEFF Research Database (Denmark)

    Rasouli, Zahra; Valverde Pérez, Borja; D'Este, Martina

    2018-01-01

    wastewater and upcycle them to feed grade single cell protein. Results demonstrated that both algae and bacteria could remove or assimilate most of the organic carbon present in the wastewater (~95% removal for monocultures and 91% for the algal-bacterial consortium). However, their growth stopped before......, for all cultures the protein content (45% of dry weight, DW, for methanotrophs; 52.5% of DW for algae; and 27.6% of DW for consortium) and amino acid profile was suitable for substitution of conventional protein sources. Further research should focus on increasing productivity of biomass grown...

  7. Amplification of marine methanotrophic enrichment DNA with 16S rDNA PCR primers for type II alpha proteobacteria methanotrophs.

    Science.gov (United States)

    Rockne, Karl J; Strand, Stuart E

    2003-09-01

    Type II alpha proteobacteria methanotrophs are capable of a wide range of cometabolic transformations of chlorinated solvents and polycyclic aromatic hydrocarbons (PAHs), and this activity has been exploited in many terrestrial bioremediation systems. However, at present, all known obligately marine methanotrophic isolates are Type I gamma proteobacteria which do not have this activity to the extent of Type II methanotrophs. In previous work in our laboratory, determining the presence of Type II alpha proteobacteria methanotrophs in marine enrichment cultures that co-metabolized PAHs required a more sensitive assay. 16S rDNA PCR primers were designed based on oligonucleotide probes for serine pathway methanotrophs and serine pathway methylotrophs with an approximate amplification fragment size of 870 base pairs. Comparison of the primers using double primer BLAST searches in established nucleotide databases showed potential amplification with all Methylocystis and Methylosinus spp., as well as potential amplification with Methylocella palustrus. DNA from Methylosinus trichosporium OB3b, a Type II methanotroph, amplified with the primers with a fragment size of approximately 850 base pairs, whereas DNA extracted from Methylomonas methanica, a Type I methanotroph, did not. The primers were used to amplify DNA extracted from two marine methanotrophic enrichment cultures: a low nitrogen/low copper enrichment to select for Type II methanotrophs and a high nitrogen/high copper enrichment to select for Type I methanotrophs. Although DNA from both cultures amplified with the PCR primers, amplification was stronger in cultures that were specifically enriched for Type II methanotrophs, suggesting the presence of higher numbers of Type II methanotrophs. These results provide further evidence for the existence of Type II marine methanotrophs, suggesting the possibility of exploiting cometabolic activity in marine systems.

  8. Aerobic methanotrophic bacteria of cold ecosystems.

    Science.gov (United States)

    Trotsenko, Yuri A; Khmelenina, Valentina N

    2005-06-01

    This review summarizes the recent advances in understanding the ecophysiological role and structure-function features of methanotrophic bacteria living in various cold ecosystems. The occurrence of methanotrophs in a majority of psychrosphere sites was verified by direct measurement of their methane-utilizing activity, by electron microscopy and immunofluorescent observations, and analyses of specific signatures in cellular phospholipids and total DNAs extracted from environmental samples. Surprisingly, the phenotypic and genotypic markers of virtually all extant methanotrophs were detected in various cold habitats, such as underground waters, Northern taiga and tundra soils, polar lakes and permafrost sediments. Also, recent findings indicated that even after long-term storage in permafrost, some methanotrophs can oxidize and assimilate methane not only at positive but also at subzero temperatures. Pure cultures of psychrophilic and psychrotolerant methanotrophs were isolated and characterized as new genera and species: Methylobacter psychrophilus, Methylosphaera hansonii, Methylocella palustris, Methylocella silvestris, Methylocella tundrae, Methylocapsa acidiphila and Methylomonas scandinavica. However, our knowledge about their adaptive mechanisms and survival in cold ecosystems remains limited and needs to be established using both traditional and molecular microbiological methods.

  9. Biodegradation of chlorinated ethenes by a methane-utilizing mixed culture

    International Nuclear Information System (INIS)

    Fogel, M.M.; Taddeo, A.R.; Fogel, S.

    1986-01-01

    Chlorinated ethenes are toxic substances which are widely distributed groundwater contaminants and are persistent in the subsurface environment. Reports on the biodegradation of these compounds under anaerobic conditions which might occur naturally in groundwater show that these substances degrade very slowly, if at all. Previous attempts to degrade chlorinated ethenes aerobically have produced conflicting results. A mixed culture containing methane-utilizing bacteria was obtained by methane enrichment of a sediment sample. Biodegradation experiments carried out in sealed culture bottles with radioactively labeled trichloroethylene (TCE) showed that approximately half of the radioactive carbon had been converted to 14 CO 2 and bacterial biomass. In addition to TCE, vinyl chloride and vinylidene chloride could be degraded to products which are not volatile chlorinated substances and are therefore likely to be further degraded to CO 2 . Two other chlorinated ethenes, cis and trans-1,2-dichloroethylene, were shown to degrade to chlorinated products, which appeared to degrade further. A sixth chlorinated ethene, tetrachloroethylene, was not degraded by the methane-utilizing culture under these conditions. The biodegradation of TCE was inhibited by acetylene, a specific inhibitor of methane oxidation by methanotrophs. This observation supported the hypothesis that a methanotroph is responsible for the observed biodegradations

  10. Facultative and obligate methanotrophs how to identify and differentiate them.

    Science.gov (United States)

    Dedysh, Svetlana N; Dunfield, Peter F

    2011-01-01

    Aerobic methanotrophs are metabolically unique bacteria that are able to utilize methane and some other C1-compounds as sole sources of carbon and energy. A defining characteristic of these organisms is the use of methane monooxygenase (MMO) enzymes to catalyze the oxidation of methane to methanol. For a long time, all methanotrophs were considered to be obligately methylotrophic, that is, unable to grow on compounds containing C-C bonds. This notion has recently been revised. Some members of the genera Methylocella, Methylocystis, and Methylocapsa are now known to be facultative methanotrophs, that is, capable of growing on methane as well as on some multicarbon substrates. The diagnosis of facultative methanotrophy in new isolates requires a great degree of caution since methanotrophic cultures are frequently contaminated by heterotrophic bacteria that survive on metabolic by-products of methanotrophs. The presence of only a few satellite cells in a culture may lead to false conclusions regarding substrate utilization, and several early reports of facultative methanotrophy are likely attributable to impure cultures. Another recurring mistake is the misidentification of nonmethanotrophic facultative methylotrophs as facultative methanotrophs. This chapter was prepared as an aid to avoid both kinds of confusion when examining methanotrophic isolates. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Biodegradation of trichloroethylene (TCE) by methanotrophic community.

    Science.gov (United States)

    Shukla, Awadhesh K; Vishwakarma, Pranjali; Upadhyay, S N; Tripathi, Anil K; Prasana, H C; Dubey, Suresh K

    2009-05-01

    Laboratory incubation experiments were carried out to assess the potential of methanotrophic culture for degrading TCE. Measurements of the growth rate and TCE degradation showed that the methanotrophs not only grew in presence of TCE but also degraded TCE. The rate of TCE degradation was found to be 0.19 ppm h(-1). The reverse transcriptase-PCR test was conducted to quantify expression of pmoA and mmoX genes. RT-PCR revealed expression of pmoA gene only. This observation provides evidence that the pmoA gene was functionally active for pMMO enzyme during the study. The diversity of the methanotrophs involved in TCE degradation was assessed by PCR amplification, cloning, restriction fragment length polymorphism and phylogenetic analysis of pmoA genes. Results suggested the occurrence of nine different phylotypes belonging to Type II methanotrophs in the enriched cultures. Out of the nine, five clustered with, genera Methylocystis and rest got clustered in to a separate group.

  12. Methylocella species are facultatively methanotrophic.

    Science.gov (United States)

    Dedysh, Svetlana N; Knief, Claudia; Dunfield, Peter F

    2005-07-01

    All aerobic methanotrophic bacteria described to date are unable to grow on substrates containing carbon-carbon bonds. Here we demonstrate that members of the recently discovered genus Methylocella are an exception to this. These bacteria are able to use as their sole energy source the one-carbon compounds methane and methanol, as well as the multicarbon compounds acetate, pyruvate, succinate, malate, and ethanol. To conclusively verify facultative growth, acetate and methane were used as model substrates in growth experiments with the type strain Methylocella silvestris BL2. Quantitative real-time PCR targeting the mmoX gene, which encodes a subunit of soluble methane monooxygenase, showed that copies of this gene increased in parallel with cell counts during growth on either acetate or methane as the sole substrate. This verified that cells possessing the genetic basis of methane oxidation grew on acetate as well as methane. Cloning of 16S rRNA genes and fluorescence in situ hybridization with strain-specific and genus-specific oligonucleotide probes detected no contaminants in cultures. The growth rate and carbon conversion efficiency were higher on acetate than on methane, and when both substrates were provided in excess, acetate was preferably used and methane oxidation was shut down. Our data demonstrate that not all methanotrophic bacteria are limited to growing on one-carbon compounds. This could have major implications for understanding the factors controlling methane fluxes in the environment.

  13. Diversity and activity of methanotrophs in alkaline soil from a Chinese coal mine.

    Science.gov (United States)

    Han, Bing; Chen, Yin; Abell, Guy; Jiang, Hao; Bodrossy, Levente; Zhao, Jiangang; Murrell, J Colin; Xing, Xin-Hui

    2009-11-01

    Culture-independent molecular biological techniques, including 16S rRNA gene and functional gene clone libraries and microarray analyses using pmoA (encoding a key subunit of particulate methane monooxygenase), were applied to investigate the methanotroph community structure in alkaline soil from a Chinese coal mine. This environment contained a high diversity of methanotrophs, including the type II methanotrophs Methylosinus/Methylocystis, type I methanotrophs related to Methylobacter/Methylosoma and Methylococcus, and a number of as yet uncultivated methanotrophs. In order to identify the metabolically active methane-oxidizing bacteria from this alkaline environment, DNA stable isotope probing (DNA-SIP) experiments using (13)CH(4) were carried out. This showed that both type I and type II methanotrophs were active, together with methanotrophs related to Methylocella, which had previously been found only in acidic environments. Methylotrophs, including Methylopila and Hyphomicrobium, were also detected in soil DNA and after DNA-SIP experiments. DNA sequence information on the most abundant, active methanotrophs in this alkaline soil will facilitate the design of oligonucleotide probes to monitor enrichment cultures when isolating key alkaliphilic methanotrophs from such environments.

  14. Diversity and activity of methanotrophs in alkaline soil from a Chinese coal mine

    Energy Technology Data Exchange (ETDEWEB)

    Han, Bing; Chen, Yin; Abell, Guy; Jiang, Hao; Bodrossy, Levente; Zhao, Jiangang; Murrell, J. Colin; Xing, Xin-Hui [Tsinghua University, Beijing (China). Dept. of Chemical Engineering

    2009-11-15

    Culture-independent molecular biological techniques, including 16S rRNA gene and functional gene clone libraries and microarray analyses using pmoA (encoding a key subunit of particulate methane monooxygenase), were applied to investigate the methanotroph community structure in alkaline soil from a Chinese coal mine. This environment contained a high diversity of methanotrophs, including the type II methanotrophs Methylosinus/Methylocystis, type I methanotrophs related to Methylobacter/Methylosoma and Methylococcus, and a number of as yet uncultivated methanotrophs. In order to identify the metabolically active methane-oxidizing bacteria from this alkaline environment, DNA stable isotope probing (DNA-SIP) experiments using {sup 13}CH{sub 4} were carried out. This showed that both type I and type II methanotrophs were active, together with methanotrophs related to Methylocella, which had previously been found only in acidic environments. Methylotrophs, including Methylopila and Hyphomicrobium, were also detected in soil DNA and after DNA-SIP experiments. DNA sequence information on the most abundant, active methanotrophs in this alkaline soil will facilitate the design of oligonucleotide probes to monitor enrichment cultures when isolating key alkaliphilic methanotrophs from such environments.

  15. Effect of Mineral Nutrients on the Kinetics of Methane Utilization by Methanotrophs

    DEFF Research Database (Denmark)

    Boiesen, Anette; Arvin, Erik; Broholm, Kim

    1993-01-01

    The effect of different mineral nutrients on the kinetics of methane biodegradation by a mixed culture of methanotrophic bacteria was studied. The substrate factors examined were ammonia, iron, copper, manganese, phosphate, and sulphide. The presence of iron in the growth medium had a strong effect...... was the only nitrogen source. The observed Monod constant for methane utilization increased with increasing concentration of ammonia. This shows that ammonia is a weak competitive inhibitor as observed by other researchers. Relatively high levels of both ammonia (70 mg/l) and copper (300 mu-g/l) inhibited...... the methane degradation, probably due to the toxic effect of copper-amine complexes....

  16. Mixed Culture PHA Production With Alternating Feedstocks

    DEFF Research Database (Denmark)

    Oliveira, C.S.S.; Duque, A.F.; Carvalho, Gilda

    Polyhydroxyalkanoates (PHA) are a sustainable alternative to conventional plastics that can be obtained from industrial wastes/by-products using mixed microbial cultures (MMC). MMC PHA production is commonly carried out in a 3-stage process consisting of an acidogenic stage, a PHA producing cultu...

  17. Mixed culture engineering for steering starter functionality

    NARCIS (Netherlands)

    Spuś, Maciej

    2016-01-01

    Undefined mixed complex starter cultures are broadly used in Gouda-type cheese production due to their robustness to phage predation, resilience for changes in environmental conditions and aroma compounds production ability during ripening. These microbial communities of lactic acid bacteria

  18. Diversity of active aerobic methanotrophs along depth profiles of arctic and subarctic lake water column and sediments

    Science.gov (United States)

    He, Ruo; Wooller, Matthew J.; Pohlman, John W.; Quensen, John; Tiedje, James M.; Leigh, Mary Beth

    2012-01-01

    Methane (CH4) emitted from high-latitude lakes accounts for 2–6% of the global atmospheric CH4 budget. Methanotrophs in lake sediments and water columns mitigate the amount of CH4 that enters the atmosphere, yet their identity and activity in arctic and subarctic lakes are poorly understood. We used stable isotope probing (SIP), quantitative PCR (Q-PCR), pyrosequencing and enrichment cultures to determine the identity and diversity of active aerobic methanotrophs in the water columns and sediments (0–25 cm) from an arctic tundra lake (Lake Qalluuraq) on the north slope of Alaska and a subarctic taiga lake (Lake Killarney) in Alaska's interior. The water column CH4 oxidation potential for these shallow (~2m deep) lakes was greatest in hypoxic bottom water from the subarctic lake. The type II methanotroph, Methylocystis, was prevalent in enrichment cultures of planktonic methanotrophs from the water columns. In the sediments, type I methanotrophs (Methylobacter, Methylosoma and Methylomonas) at the sediment-water interface (0–1 cm) were most active in assimilating CH4, whereas the type I methanotroph Methylobacter and/or type II methanotroph Methylocystis contributed substantially to carbon acquisition in the deeper (15–20 cm) sediments. In addition to methanotrophs, an unexpectedly high abundance of methylotrophs also actively utilized CH4-derived carbon. This study provides new insight into the identity and activity of methanotrophs in the sediments and water from high-latitude lakes.

  19. Glycogen metabolism in aerobic mixed cultures

    DEFF Research Database (Denmark)

    Dircks, Klaus; Beun, J.J.; van Loosdrecht, M.C.M.

    2001-01-01

    In this study, the metabolism of glycogen storage and consumption in mixed cultures under aerobic conditions is described. The experimental results are used to calibrate a metabolic model, which as sole stoichiometric variables has the efficiency of oxidative phosphorylation (delta) and maintenance...... of glycogen and subsequent growth occur without significant loss of energy, as compared with direct growth on glucose. For kinetic modeling, Monod kinetics is used most commonly in activated sludge models to describe the rate of microbial transformation. Monod kinetics, however, does not provide a good...

  20. Aquatic plant surface as a niche for methanotrophs

    Directory of Open Access Journals (Sweden)

    Naoko eYoshida

    2014-02-01

    Full Text Available This study investigated the potential local CH4 sink in various plant parts as a boundary environment of CH4 emission and consumption. By comparing CH4 consumption activities in cultures inoculated with parts from 39 plant species, we observed significantly higher consumption of CH4 associated with aquatic plants than other emergent plant parts such as woody plant leaves, macrophytic marine algae, and sea grass. In situ activity of CH4 consumption by methanotrophs associated with different species of aquatic plants was in the range of 3.7 – 37 μmol⋅h-1⋅g-1 dry weight, which was ca 5.7-370 fold higher than epiphytic CH4 consumption in submerged parts of emergent plants. The qPCR-estimated copy numbers of the particulate methane monooxygenase-encoding gene pmoA were variable among the aquatic plants and ranged in the order of 105 to 107 copies⋅g-1 dry weight, which correlated with the observed CH4 consumption activities. Phylogenetic identification of methanotrophs on aquatic plants based on the pmoA sequence analysis revealed a predominance of diverse gammaproteobacterial type-I methanotrophs, including a phylotype of a possible plant-associated methanotroph with the closest identity (86-89% to Methylocaldum gracile.

  1. Starvation and recovery in the deep-sea methanotroph Methyloprofundus sedimenti

    OpenAIRE

    Tavormina, Patricia L.; Kellermann, Matthias Y.; Antony, Chakkiath Paul; Tocheva, Elitza I.; Dalleska, Nathan F.; Jensen, Ashley J.; Valentine, David L.; Hinrichs, Kai-Uwe; Jensen, Grant J.; Dubilier, Nicole; Orphan, Victoria J.

    2017-01-01

    In the deep ocean, the conversion of methane into derived carbon and energy drives the establishment of diverse faunal communities. Yet specific biological mechanisms underlying the introduction of methane-derived carbon into the food web remain poorly described, due to a lack of cultured representative deep-sea methanotrophic prokaryotes. Here, the response of the deep-sea aerobic methanotroph Methyloprofundus sedimenti to methane starvation and recovery was characterized. By combining lipid...

  2. Methylocella Species Are Facultatively Methanotrophic

    OpenAIRE

    Dedysh, Svetlana N.; Knief, Claudia; Dunfield, Peter F.

    2005-01-01

    All aerobic methanotrophic bacteria described to date are unable to grow on substrates containing carbon-carbon bonds. Here we demonstrate that members of the recently discovered genus Methylocella are an exception to this. These bacteria are able to use as their sole energy source the one-carbon compounds methane and methanol, as well as the multicarbon compounds acetate, pyruvate, succinate, malate, and ethanol. To conclusively verify facultative growth, acetate and methane were used as mod...

  3. Biodegradation of endosulfan by mixed bacteria culture strains of ...

    African Journals Online (AJOL)

    Biodegradation of endosulfan by mixed bacteria culture strains of Pseudomonas aeruginosa and Staphylococcus aureus. Nsidibeabasi Calvin Nwokem, Calvin Onyedika Nwokem, Casmir Emmanuel Gimba, Beatrice Nkiruka Iwuala ...

  4. Intelligent control of mixed-culture bioprocesses

    International Nuclear Information System (INIS)

    Stoner, D.L.; Larsen, E.D.; Miller, K.S.

    1995-01-01

    A hierarchical control system is being developed and applied to a mixed culture bioprocess in a continuous stirred tank reactor. A bioreactor, with its inherent complexity and non-linear behavior was an interesting, yet, difficult application for control theory. The bottom level of the hierarchy was implemented as a number of integrated set point controls and data acquisition modules. Within the second level was a diagnostic system that used expert knowledge to determine the operational status of the sensors, actuators, and control modules. A diagnostic program was successfully implemented for the detection of stirrer malfunctions, and to monitor liquid delivery rates and recalibrate the pumps when deviations from desired flow rates occurred. The highest control level was a supervisory shell that was developed using expert knowledge and the history of the reactor operation to determine the set points required to meet a set of production criteria. At this stage the supervisory shell analyzed the data to determine the state of the system. In future implementations, this shell will determine the set points required to optimize a cost function using expert knowledge and adaptive learning techniques

  5. Intelligent control of mixed-culture bioprocesses

    Energy Technology Data Exchange (ETDEWEB)

    Stoner, D.L.; Larsen, E.D.; Miller, K.S. [Idaho National Engineering Lab., Idaho Falls, ID (United States)] [and others

    1995-12-31

    A hierarchical control system is being developed and applied to a mixed culture bioprocess in a continuous stirred tank reactor. A bioreactor, with its inherent complexity and non-linear behavior was an interesting, yet, difficult application for control theory. The bottom level of the hierarchy was implemented as a number of integrated set point controls and data acquisition modules. Within the second level was a diagnostic system that used expert knowledge to determine the operational status of the sensors, actuators, and control modules. A diagnostic program was successfully implemented for the detection of stirrer malfunctions, and to monitor liquid delivery rates and recalibrate the pumps when deviations from desired flow rates occurred. The highest control level was a supervisory shell that was developed using expert knowledge and the history of the reactor operation to determine the set points required to meet a set of production criteria. At this stage the supervisory shell analyzed the data to determine the state of the system. In future implementations, this shell will determine the set points required to optimize a cost function using expert knowledge and adaptive learning techniques.

  6. Monitoring Methanotrophic Bacteria in Hybrid Anaerobic-Aerobic Reactors with PCR and a Catabolic Gene Probe

    Science.gov (United States)

    Miguez, Carlos B.; Shen, Chun F.; Bourque, Denis; Guiot, Serge R.; Groleau, Denis

    1999-01-01

    We attempted to mimic in small upflow anaerobic sludge bed (UASB) bioreactors the metabolic association found in nature between methanogens and methanotrophs. UASB bioreactors were inoculated with pure cultures of methanotrophs, and the bioreactors were operated by using continuous low-level oxygenation in order to favor growth and/or survival of methanotrophs. Unlike the reactors in other similar studies, the hybrid anaerobic-aerobic bioreactors which we used were operated synchronously, not sequentially. Here, emphasis was placed on monitoring various methanotrophic populations by using classical methods and also a PCR amplification assay based on the mmoX gene fragment of the soluble methane monooxygenase (sMMO). The following results were obtained: (i) under the conditions used, Methylosinus sporium appeared to survive better than Methylosinus trichosporium; (ii) the PCR method which we used could detect as few as about 2,000 sMMO gene-containing methanotrophs per g (wet weight) of granular sludge; (iii) inoculation of the bioreactors with pure cultures of methanotrophs contributed greatly to increases in the sMMO-containing population (although the sMMO-containing population decreased gradually with time, at the end of an experiment it was always at least 2 logs larger than the initial population before inoculation); (iv) in general, there was a good correlation between populations with the sMMO gene and populations that exhibited sMMO activity; and (v) inoculation with sMMO-positive cultures helped increase significantly the proportion of sMMO-positive methanotrophs in reactors, even after several weeks of operation under various regimes. At some point, anaerobic-aerobic bioreactors like those described here might be used for biodegradation of various chlorinated pollutants. PMID:9925557

  7. Growth effects on mixed culture of Dunaliella salina and ...

    African Journals Online (AJOL)

    AJL

    2011-10-10

    Oct 10, 2011 ... compounds of nutritional supplements or food additives. (Wikfors and Ohno ... mixed cultures of marine microalgae and most of the work has been ..... This work was supported by the National Natural Science. Foundation of ...

  8. Resilience of (seed bank) aerobic methanotrophs and methanotrophic activity to desiccation and heat stress.

    NARCIS (Netherlands)

    Ho, A.; Lueke, C.; Reim, A.; Frenzel, P.

    2016-01-01

    In seasonally changing environments, aerobic methanotrophs are exposed to elevated temperatures and drought. Prior exposure to adverse conditions (site history) may leave an imprint on the methanotrophic community composition in the form of a seed bank. While the significance of a microbial seed

  9. Mixed-culture transcriptome analysis reveals the molecular basis of mixed-culture growth in Streptococcus thermophilus and Lactobacillus bulgaricus

    NARCIS (Netherlands)

    Sieuwerts, S.; Molenaar, D.; Hijum, van S.A.F.T.; Beerthuyzen, M.; Stevens, M.J.A.; Janssen, P.W.; Ingham, C.J.; Bok, de F.A.M.; Vos, de W.M.; Hylckama Vlieg, van J.E.T.

    2010-01-01

    Many food fermentations are performed using mixed cultures of lactic acid bacteria. Interactions between strains are of key importance for the performance of these fermentations. Yogurt fermentation by Streptococcus thermophilus and Lactobacillus bulgaricus (basonym, Lactobacillus delbrueckii subsp.

  10. Mixed Reality Cultural Heritage Communication - The Zea Case

    DEFF Research Database (Denmark)

    Veirum, Niels Einar; Christensen, Mogens Fiil; Mayerhofer, Mikkel

    Case is a design scenario for the Museum of the Future showing how Cultural Heritage institutions can use a Glocal Approach to technology and architecture to reinvent the relation to the visitor and the neighbourhood. While Mixed Reality can be used for Cultural Heritage Communication in traditional...

  11. Energetics of binary mixed culture of Pseudomonas aeruginosa and ...

    African Journals Online (AJOL)

    Bioenergetic analysis of the growth of the binary mixed culture (Pseudomonas aeruginosa and Pseudomonas fluorescence) on phenol chemostat culture was carried out. The data were checked for consistency using carbon and available electron balances. When more than the minimum number of variables are measured, ...

  12. Survival and Recovery of Methanotrophic Bacteria Starved Under Oxic and Anoxic Conditions

    Science.gov (United States)

    Roslev, Peter; King, Gary M.

    1994-01-01

    The effects of carbon deprivation on survival of methanotrophic bacteria were compared in cultures incubated in the presence and absence of oxygen in the starvation medium. Survival and recovery of the examined methanotrophs were generally highest for cultures starved under anoxic conditions as indicated by poststarvation measurements of methane oxidation, tetrazolium salt reduction, plate counts, and protein synthesis. Methylosinus trichosporium OB3b survived up to 6 weeks of carbon deprivation under anoxic conditions while maintaining a physiological state that allowed relatively rapid (hours) methane oxidation after substrate addition. A small fraction of cells starved under oxic and anoxic conditions (4 and 10%, respectively) survived more than 10 weeks but required several days for recovery on plates and in liquid medium. A non-spore-forming methanotroph, strain WP 12, displayed 36 to 118% of its initial methane oxidation capacity after 5 days of carbon deprivation. Oxidation rates varied with growth history prior to the experiments as well as with starvation conditions. Strain WP 12 starved under anoxic conditions showed up to 90% higher methane oxidation activity and 46% higher protein production after starvation than did cultures starved under oxic conditions. Only minor changes in biomass and niorpholow were seen for methanotrophic bacteria starved tinder anoxic conditions. In contrast, starvation under oxic conditions resulted in morphology changes and an initial 28 to 35% loss of cell protein. These data suggest that methanotrophic bacteria can survin,e carbon deprivation under anoxic conditions by using maintenance energy derived Solelyr from an anaerobic endogenous metabolism. This capability could partly explain a significant potential for methane oxidation in environments not continuously, supporting aerobic methanotrophic growth.

  13. Optimum O2:CH4 Ratio Promotes the Synergy between Aerobic Methanotrophs and Denitrifiers to Enhance Nitrogen Removal

    Directory of Open Access Journals (Sweden)

    Jing Zhu

    2017-06-01

    Full Text Available The O2:CH4 ratio significantly effects nitrogen removal in mixed cultures where aerobic methane oxidation is coupled with denitrification (AME-D. The goal of this study was to investigate nitrogen removal of the AME-D process at four different O2:CH4 ratios [0, 0.05, 0.25, and 1 (v/v]. In batch tests, the highest denitrifying activity was observed when the O2:CH4 ratio was 0.25. At this ratio, the methanotrophs produced sufficient carbon sources for denitrifiers and the oxygen level did not inhibit nitrite removal. The results indicated that the synergy between methanotrophs and denitrifiers was significantly improved, thereby achieving a greater capacity of nitrogen removal. Based on thermodynamic and chemical analyses, methanol, butyrate, and formaldehyde could be the main trophic links of AME-D process in our study. Our research provides valuable information for improving the practical application of the AME-D systems.

  14. Do Mixed-Flora Preoperative Urine Cultures Matter?

    Science.gov (United States)

    Polin, Michael R; Kawasaki, Amie; Amundsen, Cindy L; Weidner, Alison C; Siddiqui, Nazema Y

    2017-06-01

    To determine whether mixed-flora preoperative urine cultures, as compared with no-growth preoperative urine cultures, are associated with a higher prevalence of postoperative urinary tract infections (UTIs). This was a retrospective cohort study. Women who underwent urogynecologic surgery were included if their preoperative clean-catch urine culture result was mixed flora or no growth. Women were excluded if they received postoperative antibiotics for reasons other than treatment of a UTI. Women were divided into two cohorts based on preoperative urine culture results-mixed flora or no growth; the prevalence of postoperative UTI was compared between cohorts. Baseline characteristics were compared using χ 2 or Student t tests. A logistic regression analysis then was performed. We included 282 women who were predominantly postmenopausal, white, and overweight. There were many concomitant procedures; 46% underwent a midurethral sling procedure and 68% underwent pelvic organ prolapse surgery. Preoperative urine cultures resulted as mixed flora in 192 (68%) and no growth in 90 (32%) patients. Overall, 14% were treated for a UTI postoperatively. There was no difference in the proportion of patients treated for a postoperative UTI between the two cohorts (25 mixed flora vs 13 no growth, P = 0.77). These results remained when controlling for potentially confounding variables in a logistic regression model (adjusted odds ratio 0.92, 95% confidence interval 0.43-1.96). In women with mixed-flora compared with no-growth preoperative urine cultures, there were no differences in the prevalence of postoperative UTI. The clinical practice of interpreting mixed-flora cultures as negative is appropriate.

  15. Mixed-culture transcriptome analysis reveals the molecular basis of mixed-culture growth in Streptococcus thermophilus and Lactobacillus bulgaricus.

    Science.gov (United States)

    Sieuwerts, Sander; Molenaar, Douwe; van Hijum, Sacha A F T; Beerthuyzen, Marke; Stevens, Marc J A; Janssen, Patrick W M; Ingham, Colin J; de Bok, Frank A M; de Vos, Willem M; van Hylckama Vlieg, Johan E T

    2010-12-01

    Many food fermentations are performed using mixed cultures of lactic acid bacteria. Interactions between strains are of key importance for the performance of these fermentations. Yogurt fermentation by Streptococcus thermophilus and Lactobacillus bulgaricus (basonym, Lactobacillus delbrueckii subsp. bulgaricus) is one of the best-described mixed-culture fermentations. These species are believed to stimulate each other's growth by the exchange of metabolites such as folic acid and carbon dioxide. Recently, postgenomic studies revealed that an upregulation of biosynthesis pathways for nucleotides and sulfur-containing amino acids is part of the global physiological response to mixed-culture growth in S. thermophilus, but an in-depth molecular analysis of mixed-culture growth of both strains remains to be established. We report here the application of mixed-culture transcriptome profiling and a systematic analysis of the effect of interaction-related compounds on growth, which allowed us to unravel the molecular responses associated with batch mixed-culture growth in milk of S. thermophilus CNRZ1066 and L. bulgaricus ATCC BAA-365. The results indicate that interactions between these bacteria are primarily related to purine, amino acid, and long-chain fatty acid metabolism. The results support a model in which formic acid, folic acid, and fatty acids are provided by S. thermophilus. Proteolysis by L. bulgaricus supplies both strains with amino acids but is insufficient to meet the biosynthetic demands for sulfur and branched-chain amino acids, as becomes clear from the upregulation of genes associated with these amino acids in mixed culture. Moreover, genes involved in iron uptake in S. thermophilus are affected by mixed-culture growth, and genes coding for exopolysaccharide production were upregulated in both organisms in mixed culture compared to monocultures. The confirmation of previously identified responses in S. thermophilus using a different strain combination

  16. Methanotrophic abundance and community fingerprint in pine and ...

    African Journals Online (AJOL)

    methanotrophs) is important to assess the microbial oxidation of the greenhouse gas methane (CH4) in soil under different land uses. Soil samples were collected from two plantation plots of pine and tea in southern China. Methanotrophic abundance ...

  17. Estimating the Biodegradation Kinetics by Mixed Culture Degrading Pyrene (Pyr

    Directory of Open Access Journals (Sweden)

    B. S. U. Ibn Abubakar

    2017-02-01

    Full Text Available Biodegradation and kinetics of Pyrene (Pyr degradation by a mixed culture previously isolated from hydrocarbon-polluted soil were conducted. Preliminary investigation on environmental factors affecting the degradation of Pyr such as temperature, pH and concentrations of Pyr was performed. These factors were optimised and established in aqueous experiments. In order to develop kinetics of Pyr degradation, an optimum temperature of 30oC and pH of 7.0 was used. Biodegradation kinetics was carried out, at first, using higher concentration between (100-700 ppm as sole source of carbon in mineral salt medium (MSM supplemented with 0.1% yeast extract. The result indicated that a range of concentration between (100-700 ppm inhibits the performance of the mixed culture. A concentration range between (10-100 ppm did not inhibit the growth of the mixed culture. A First-order rate constant, k was higher (0.0487 mg/lh with a substrate concentration of 20 ppm than other concentrations. The average degradation rate constant is 0.0029 mg/Lh for all the concentrations tested. This indicated that the mixed culture could degrade over 0.0696 ppm of Pyr per day. It also confirmed that kinetics of microbial degradation was partially fitted into Monod model. The data can be used to estimate biodegradation of Pyr by a mixed culture and preliminarily estimation of degradation rates.

  18. Bacteriohopanepolyol signatures as markers for methanotrophic bacteria in peat moss

    NARCIS (Netherlands)

    van Winden, J.F.; Talbot, H.M.; Kip, N.; Reichart, G.J.; Pol, A.; McNamara, N.P.; Jetten, M.S.M.; Op den Camp, H.J.M.; Sinninghe Damsté, J.S.

    2012-01-01

    Bacteriohopanepolyols (BHPs) are bacterial biomarkers with a likely potential to identify present and past methanotrophic communities. To unravel the methanotrophic community in peat bogs, we report the BHP signatures of type I and type II methanotrophs isolated from Sphagnum mosses and of an

  19. Bacteriohopanepolyol signatures as markers for methanotrophic bacteria in peat moss

    Science.gov (United States)

    van Winden, Julia F.; Talbot, Helen M.; Kip, Nardy; Reichart, Gert-Jan; Pol, Arjan; McNamara, Niall P.; Jetten, Mike S. M.; Op den Camp, Huub J. M.; Sinninghe Damsté, Jaap S.

    2012-01-01

    Bacteriohopanepolyols (BHPs) are bacterial biomarkers with a likely potential to identify present and past methanotrophic communities. To unravel the methanotrophic community in peat bogs, we report the BHP signatures of type I and type II methanotrophs isolated from Sphagnum mosses and of an extreme acidophilic verrucomicrobial methanotroph. A type I Methylovulum-like strain (M200) contains a remarkable combination of BHPs, including a complete suite of mono-unsaturated aminobacteriohopanepentol, -tetrol and -triol. The Methylomonas-like strain (M5) mainly produces aminobacteriohopanepentol, characteristic for type I methanotrophs, and the Methylosinus-like strain (29) contains both aminobacteriohopanetetrol and aminobacteriohopanetriol, typical for a type II methanotroph. The type II methanotroph Methylocella palustris and the verrucomicrobial Methylacidiphilum fumariolicum strain SolV primarily produce aminotriol, which is also produced by many other bacteria. In Sphagnum mosses and underlying peat from a peat bog from Moorhouse, UK, the only detectable BHPs indicative of methanotrophs are aminobacteriohopanepentol (aminopentol) and aminobacteriohopanetetrol (aminotetrol), although both are relatively low in abundance compared to other BHPs. Aminopentol serves as a marker for type I methanotrophs, while aminotetrol may reflect the presence of both type I and type II methanotrophs. The similar quantities of aminotetrol and aminopentol indicate that the methanotrophic community in Sphagnum peat probably consist of a combination of both type I and type II methanotrophs, which is in line with previously published pmoA-based micro-array results.

  20. Bacteriohopanepolyol signatures as markers for methanotrophic bacteria in peat moss

    NARCIS (Netherlands)

    Winden, J.F. van; Talbot, H.M.; Kip, N.; Reichart, G.-J.; Pol, A.; McNamara, N.P.; Jetten, M.S.M.; Camp, H.J.M. Op den; Sinninghe Damsté, J.S.

    2012-01-01

    Bacteriohopanepolyols (BHPs) are bacterial biomarkers with a likely potential to identify present and past methanotrophic communities. To unravel the methanotrophic community inpeat bogs, we report the BHP signatures of type I and type II methanotrophs isolated from Sphagnummosses and of an extreme

  1. Termites facilitate methane oxidation and shape the methanotrophic community

    NARCIS (Netherlands)

    Ho, A.; Erens, H.; Mujinya, B.B.; Boeckx, P.; Baert, G.; Schneider, B.; Frenzel, P.; Boon, N.; Van Ranst, E.

    2013-01-01

    Termite-derived methane contributes 3-4% to the total methane budget globally. Termites are not known to harbor methane-oxidizing microorganisms (methanotrophs). However, a considerable fraction of methane produced can be consumed by methanotrophs that inhabit the mound material. Yet, methanotroph

  2. Secretion of Flavins by Three Species of Methanotrophic Bacteria▿ †

    OpenAIRE

    Balasubramanian, Ramakrishnan; Levinson, Benjamin T.; Rosenzweig, Amy C.

    2010-01-01

    We detected flavins in the growth medium of the methanotrophic bacterium Methylocystis species strain M. Flavin secretion correlates with growth stage and increases under iron starvation conditions. Two other methanotrophs, Methylosinus trichosporium OB3b and Methylococcus capsulatus (Bath), secrete flavins, suggesting that flavin secretion may be common to many methanotrophic bacteria.

  3. Fostering cultural inclusiveness and learning in culturally mixed business classes.

    Science.gov (United States)

    Mak, Anita S; Daly, Anne; Barker, Michelle C

    2014-01-01

    Business educators have advocated that in order to build faculty's intercultural capability, it is vital to provide them with professional development in using intercultural training resources and with "community of practice" support in adapting such resources for enhancing their students' intercultural learning. This approach has been adopted in an Australian action research project titled "Internationalisation at Home" (IaH), which involved providing faculty with professional development adapted from an established intercultural training resource - the EXCELL (Excellence in Cultural Experiential Learning and Leadership) Program. In this paper, we present two case studies of the implementation of the IaH Project in business schools at the University of Canberra and at Griffith University. Lessons learned from the first study were incorporated in the design and evaluation of the second one. Faculty leaders will describe how they engage and support colleagues in adapting components of EXCELL to foster cultural inclusiveness and facilitate students' intercultural competence development. As part of project evaluation, we hypothesised that students who participated in IaH courses would report greater levels of (1) cultural inclusiveness in their educational environment, and (2) cultural learning development, compared with students who were not enrolled in IaH courses. Research participants in the Canberra case study comprised an intervention group of 140 business undergraduates enrolled in an IaH course, and a control group of 59 non-IaH undergraduates. At Griffith, participants were 211 first year management students in the intervention group and 84 students enrolled in a non-IaH first year course. In each case study, an end-of-semester survey showed that students who had completed courses with the IaH project intervention reported significantly greater levels of perceived cultural inclusiveness in multicultural classes, and of cultural learning development, than

  4. Oxygen-limited metabolism in the methanotroph Methylomicrobium buryatense 5GB1C

    Directory of Open Access Journals (Sweden)

    Alexey Gilman

    2017-10-01

    Full Text Available The bacteria that grow on methane aerobically (methanotrophs support populations of non-methanotrophs in the natural environment by excreting methane-derived carbon. One group of excreted compounds are short-chain organic acids, generated in highest abundance when cultures are grown under O2-starvation. We examined this O2-starvation condition in the methanotroph Methylomicrobium buryatense 5GB1. The M. buryatense 5GB1 genome contains homologs for all enzymes necessary for a fermentative metabolism, and we hypothesize that a metabolic switch to fermentation can be induced by low-O2 conditions. Under prolonged O2-starvation in a closed vial, this methanotroph increases the amount of acetate excreted about 10-fold, but the formate, lactate, and succinate excreted do not respond to this culture condition. In bioreactor cultures, the amount of each excreted product is similar across a range of growth rates and limiting substrates, including O2-limitation. A set of mutants were generated in genes predicted to be involved in generating or regulating excretion of these compounds and tested for growth defects, and changes in excretion products. The phenotypes and associated metabolic flux modeling suggested that in M. buryatense 5GB1, formate and acetate are excreted in response to redox imbalance. Our results indicate that even under O2-starvation conditions, M. buryatense 5GB1 maintains a metabolic state representing a combination of fermentation and respiration metabolism.

  5. Production and consumption of nitric oxide by three methanotrophic bacteria.

    Science.gov (United States)

    Ren, T; Roy, R; Knowles, R

    2000-09-01

    We studied nitrogen oxide production and consumption by methanotrophs Methylobacter luteus (group I), Methylosinus trichosporium OB3b (group II), and an isolate from a hardwood swamp soil, here identified by 16S ribosomal DNA sequencing as Methylobacter sp. strain T20 (group I). All could consume nitric oxide (nitrogen monoxide, NO), and produce small amounts of nitrous oxide (N(2)O). Only Methylobacter strain T20 produced large amounts of NO (>250 parts per million by volume [ppmv] in the headspace) at specific activities of up to 2.0 x 10(-17) mol of NO cell(-1) day(-1), mostly after a culture became O(2) limited. Production of NO by strain T20 occurred mostly in nitrate-containing medium under anaerobic or nearly anaerobic conditions, was inhibited by chlorate, tungstate, and O(2), and required CH(4). Denitrification (methanol-supported N(2)O production from nitrate in the presence of acetylene) could not be detected and thus did not appear to be involved in the production of NO. Furthermore, cd(1) and Cu nitrite reductases, NO reductase, and N(2)O reductase could not be detected by PCR amplification of the nirS, nirK, norB, and nosZ genes, respectively. M. luteus and M. trichosporium produced some NO in ammonium-containing medium under aerobic conditions, likely as a result of methanotrophic nitrification and chemical decomposition of nitrite. For Methylobacter strain T20, arginine did not stimulate NO production under aerobiosis, suggesting that NO synthase was not involved. We conclude that strain T20 causes assimilatory reduction of nitrate to nitrite, which then decomposes chemically to NO. The production of NO by methanotrophs such as Methylobacter strain T20 could be of ecological significance in habitats near aerobic-anaerobic interfaces where fluctuating O(2) and nitrate availability occur.

  6. Growth of microbial mixed cultures under anaerobic, alkaline conditions

    International Nuclear Information System (INIS)

    Wenk, M.

    1993-09-01

    Cement and concrete are the most important engineered barrier materials in a repository for low- and intermediate-level waste and thus represent the most significant component of the total disposal inventory. Based on the chemical composition of the concrete used in the repository and the groundwater fluxes in the modelled host rock, it is to be expected that the pH in the near vicinity of the repository could exceed a value of 10.5 for more than a million years. The groundwater in the repository environment also has a limited carbon concentration. Since microorganisms will be present in a repository and can even find suitable living conditions within the waste itself, investigations were carried out in order to establish the extent to which microbial activity is possible under the extreme conditions of the repository near-field. For the investigations, alkalophilic cultures were enriched from samples from alkaline habitats and from Valanginian Marl. Anaerobic bacteria with fermentative, sulfate-reducing and methanogenic metabolism were selected. The growth and activity of the mixed cultures were studied under alkaline conditions and the dependence on pH and carbon concentration determined. All the mixed cultures investigated are alkalophilic. The optimum growth range for the cultures is between pH 9.0 and pH 10.0. The activity limit for the fermentative mixed culture is at pH 12, for the sulfate-reducers at pH 11 and for the methanogens at pH 10.5. Given the limited supply of carbon, the mixed cultures can only grow under slightly alkaline conditions. Only the fermentative cultures are capable of surviving with limited carbon supply at pH 13. (author) 24 figs., 18 tabs., 101 refs

  7. Influence of mixed culture system on the growth performance of ...

    African Journals Online (AJOL)

    This study describes a novel strategy to improve the α-galactosidase and invertase production of Saccharomyces cerevisiae by co-cultivating it with Aspergillus oryzae. In the mixed culture, the growth of the both strains was repressed, and the protein synthesis for the yeast cell wall was promoted significantly. As a result ...

  8. Growth effects on mixed culture of Dunaliella salina and ...

    African Journals Online (AJOL)

    Dunaliella salina and Phaeodactylum tricornutum are two important marine microalgae rich in bioactive substances and other high-value constituents. In this study, growth effects on mixed culture of these two microalgae were studied under different inoculation proportions (10:0, 7:3, 5:5, 3:7, 0:10) and low, medium and high ...

  9. Improvement of acid protease production by a mixed culture of ...

    African Journals Online (AJOL)

    The synthesis of acid protease by Aspergillus oryzae AS3042 was enhanced significantly with the mixed culture of Aspergillus niger SL-09 using solid-state fermentation technique. The influence of carbon sources, nitrogen sources and the addition of phytic acid on acid protease production were investigated. The enzyme ...

  10. Methane Oxidation and Molecular Characterization of Methanotrophs from a Former Mercury Mine Impoundment

    Directory of Open Access Journals (Sweden)

    Shaun M. Baesman

    2015-06-01

    Full Text Available The Herman Pit, once a mercury mine, is an impoundment located in an active geothermal area. Its acidic waters are permeated by hundreds of gas seeps. One seep was sampled and found to be composed of mostly CO2 with some CH4 present. The δ13CH4 value suggested a complex origin for the methane: i.e., a thermogenic component plus a biological methanogenic portion. The relatively 12C-enriched CO2 suggested a reworking of the ebullitive methane by methanotrophic bacteria. Therefore, we tested bottom sediments for their ability to consume methane by conducting aerobic incubations of slurried materials. Methane was removed from the headspace of live slurries, and subsequent additions of methane resulted in faster removal rates. This activity could be transferred to an artificial, acidic medium, indicating the presence of acidophilic or acid-tolerant methanotrophs, the latter reinforced by the observation of maximum activity at pH = 4.5 with incubated slurries. A successful extraction of sterol and hopanoid lipids characteristic of methanotrophs was achieved, and their abundances greatly increased with increased sediment methane consumption. DNA extracted from methane-oxidizing enrichment cultures was amplified and sequenced for pmoA genes that aligned with methanotrophic members of the Gammaproteobacteria. An enrichment culture was established that grew in an acidic (pH 4.5 medium via methane oxidation.

  11. Methane oxidation and molecular characterization of methanotrophs from a former mercury mine impoundment

    Science.gov (United States)

    Baesman, Shaun; Miller, Laurence G.; Wei, Jeremy H.; Cho, Yirang; Matys, Emily D.; Summons, Roger E.; Welander, Paula V.; Oremland, Ronald S.

    2015-01-01

    The Herman Pit, once a mercury mine, is an impoundment located in an active geothermal area. Its acidic waters are permeated by hundreds of gas seeps. One seep was sampled and found to be composed of mostly CO2 with some CH4 present. The δ13CH4 value suggested a complex origin for the methane: i.e., a thermogenic component plus a biological methanogenic portion. The relatively 12C-enriched CO2 suggested a reworking of the ebullitive methane by methanotrophic bacteria. Therefore, we tested bottom sediments for their ability to consume methane by conducting aerobic incubations of slurried materials. Methane was removed from the headspace of live slurries, and subsequent additions of methane resulted in faster removal rates. This activity could be transferred to an artificial, acidic medium, indicating the presence of acidophilic or acid-tolerant methanotrophs, the latter reinforced by the observation of maximum activity at pH = 4.5 with incubated slurries. A successful extraction of sterol and hopanoid lipids characteristic of methanotrophs was achieved, and their abundances greatly increased with increased sediment methane consumption. DNA extracted from methane-oxidizing enrichment cultures was amplified and sequenced for pmoA genes that aligned with methanotrophic members of the Gammaproteobacteria. An enrichment culture was established that grew in an acidic (pH 4.5) medium via methane oxidation.

  12. Modelling the growth of a methanotrophic biofilm

    DEFF Research Database (Denmark)

    Arcangeli, J.-P.; Arvin, E.

    1999-01-01

    This article discusses the growth of methanotrophic biofilms. Several independent biofilm growths scenarios involving different inocula were examined. Biofilm growth, substrate removal and product formation were monitored throughout the experiments. Based on the oxygen consumption it was concluded...... that heterotrophs and nitrifiers co-existed with methanotrophs in the biofilm. Heterotrophic biomass grew on soluble polymers formed by the hydrolysis of dead biomass entrapped in the biofilm. Nitrifier populations developed because of the presence of ammonia in the mineral medium. Based on these experimental...... was performed on this model. It indicated that the most influential parameters were those related to the biofilm (i.e. density; solid-volume fraction; thickness). This suggests that in order to improve the model, further research regarding the biofilm structure and composition is needed....

  13. Metabolic modelling of polyhydroxyalkanoate copolymers production by mixed microbial cultures

    Directory of Open Access Journals (Sweden)

    Reis Maria AM

    2008-07-01

    Full Text Available Abstract Background This paper presents a metabolic model describing the production of polyhydroxyalkanoate (PHA copolymers in mixed microbial cultures, using mixtures of acetic and propionic acid as carbon source material. Material and energetic balances were established on the basis of previously elucidated metabolic pathways. Equations were derived for the theoretical yields for cell growth and PHA production on mixtures of acetic and propionic acid as functions of the oxidative phosphorylation efficiency, P/O ratio. The oxidative phosphorylation efficiency was estimated from rate measurements, which in turn allowed the estimation of the theoretical yield coefficients. Results The model was validated with experimental data collected in a sequencing batch reactor (SBR operated under varying feeding conditions: feeding of acetic and propionic acid separately (control experiments, and the feeding of acetic and propionic acid simultaneously. Two different feast and famine culture enrichment strategies were studied: (i either with acetate or (ii with propionate as carbon source material. Metabolic flux analysis (MFA was performed for the different feeding conditions and culture enrichment strategies. Flux balance analysis (FBA was used to calculate optimal feeding scenarios for high quality PHA polymers production, where it was found that a suitable polymer would be obtained when acetate is fed in excess and the feeding rate of propionate is limited to ~0.17 C-mol/(C-mol.h. The results were compared with published pure culture metabolic studies. Conclusion Acetate was more conducive toward the enrichment of a microbial culture with higher PHA storage fluxes and yields as compared to propionate. The P/O ratio was not only influenced by the selected microbial culture, but also by the carbon substrate fed to each culture, where higher P/O ratio values were consistently observed for acetate than propionate. MFA studies suggest that when mixtures of

  14. [Methanotrophic bacteria of acid sphagnum bogs].

    Science.gov (United States)

    Dedysh, S N

    2002-01-01

    Acid sphagnum bogs cover a considerable part of the territory of Russia and are an important natural source of biogenic methane, which is formed in their anaerobic layers. A considerable portion of this methane is consumed in the aerobic part of the bog profile by acidophilic methanotrophic bacteria, which comprise the methane filter of sphagnum bogs and decrease CH4 emission to the atmosphere. For a long time, these bacteria escaped isolation, which became possible only after the elucidation of the optimal conditions of their functioning in situ: pH 4.5 to 5.5; temperature, from 15 to 20 degrees C; and low salt concentration in the solution. Reproduction of these conditions and rejection of earlier used media with a high content of biogenic elements allowed methanotrophic bacteria of two new genera and species--Methylocella palustris and Methylocapsa acidophila--to be isolated from the peat of sphagnum bogs of the northern part of European Russia and West Siberia. These bacteria are well adapted to the conditions in cold, acid, oligotrophic sphagnum bogs. They grow in a pH range of 4.2-7.5 with an optimum at 5.0-5.5, prefer moderate temperatures (15-25 degrees C) and media with a low content of mineral salts (200-500 mg/l), and are capable of active nitrogen fixation. Design of fluorescently labeled 16S rRNA-targeted oligonucleotide probes for the detection of Methylocella palustris and Methylocapsa acidophila and their application to the analysis of sphagnum peat samples showed that these bacteria represent dominant populations of methanotrophs with a density of 10(5)-10(6) cells/g peat. In addition to Methylocella and Methylocapsa populations, one more abundant population of methanotrophs was revealed (10(6) cells/g peat), which were phylogenetically close to the genus Methylocystis.

  15. Mixed messages: residents' experiences learning cross-cultural care.

    Science.gov (United States)

    Park, Elyse R; Betancourt, Joseph R; Kim, Minah K; Maina, Angela W; Blumenthal, David; Weissman, Joel S

    2005-09-01

    An Institute of Medicine report issued in 2002 cited cross-cultural training as a mechanism to address racial and ethnic disparities in health care, but little is known about residents' training and capabilities to provide quality care to diverse populations. This article explores a select group of residents' perceptions of their preparedness to deliver quality care to diverse populations. Seven focus groups and ten individual interviews were conducted with 68 residents in locations nationwide. Qualitative analysis of focus-group and individual interview transcripts was performed to assess residents' perceptions of (1) preparedness to deliver care to diverse patients; (2) educational climate; and (3) training experiences. Most residents in this study noted the importance of cross-cultural care yet reported little formal training in this area. Residents wanted more formal training yet expressed concern that culture-specific training could lead to stereotyping. Most residents had developed ad hoc, informal skills to care for diverse patients. Although residents perceived institutional endorsement, they sensed it was a low priority due to lack of time and resources. Residents in this study reported receiving mixed messages about cross-cultural care. They were told it is important, yet they received little formal training and did not have time to treat diverse patients in a culturally sensitive manner. As a result, many developed coping behaviors rather than skills based on formally taught best practices. Training environments need to increase training to enhance residents' preparedness to deliver high-quality cross-cultural care if the medical profession is to achieve the goals set by the Institute of Medicine.

  16. Termites facilitate methane oxidation and shape the methanotrophic community.

    Science.gov (United States)

    Ho, Adrian; Erens, Hans; Mujinya, Basile Bazirake; Boeckx, Pascal; Baert, Geert; Schneider, Bellinda; Frenzel, Peter; Boon, Nico; Van Ranst, Eric

    2013-12-01

    Termite-derived methane contributes 3 to 4% to the total methane budget globally. Termites are not known to harbor methane-oxidizing microorganisms (methanotrophs). However, a considerable fraction of the methane produced can be consumed by methanotrophs that inhabit the mound material, yet the methanotroph ecology in these environments is virtually unknown. The potential for methane oxidation was determined using slurry incubations under conditions with high (12%) and in situ (∼0.004%) methane concentrations through a vertical profile of a termite (Macrotermes falciger) mound and a reference soil. Interestingly, the mound material showed higher methanotrophic activity. The methanotroph community structure was determined by means of a pmoA-based diagnostic microarray. Although the methanotrophs in the mound were derived from populations in the reference soil, it appears that termite activity selected for a distinct community. Applying an indicator species analysis revealed that putative atmospheric methane oxidizers (high-indicator-value probes specific for the JR3 cluster) were indicative of the active nest area, whereas methanotrophs belonging to both type I and type II were indicative of the reference soil. We conclude that termites modify their environment, resulting in higher methane oxidation and selecting and/or enriching for a distinct methanotroph population.

  17. Intercellular wiring enables electron transfer between methanotrophic archaea and bacteria.

    Science.gov (United States)

    Wegener, Gunter; Krukenberg, Viola; Riedel, Dietmar; Tegetmeyer, Halina E; Boetius, Antje

    2015-10-22

    The anaerobic oxidation of methane (AOM) with sulfate controls the emission of the greenhouse gas methane from the ocean floor. In marine sediments, AOM is performed by dual-species consortia of anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB) inhabiting the methane-sulfate transition zone. The biochemical pathways and biological adaptations enabling this globally relevant process are not fully understood. Here we study the syntrophic interaction in thermophilic AOM (TAOM) between ANME-1 archaea and their consortium partner SRB HotSeep-1 (ref. 6) at 60 °C to test the hypothesis of a direct interspecies exchange of electrons. The activity of TAOM consortia was compared to the first ANME-free culture of an AOM partner bacterium that grows using hydrogen as the sole electron donor. The thermophilic ANME-1 do not produce sufficient hydrogen to sustain the observed growth of the HotSeep-1 partner. Enhancing the growth of the HotSeep-1 partner by hydrogen addition represses methane oxidation and the metabolic activity of ANME-1. Further supporting the hypothesis of direct electron transfer between the partners, we observe that under TAOM conditions, both ANME and the HotSeep-1 bacteria overexpress genes for extracellular cytochrome production and form cell-to-cell connections that resemble the nanowire structures responsible for interspecies electron transfer between syntrophic consortia of Geobacter. HotSeep-1 highly expresses genes for pili production only during consortial growth using methane, and the nanowire-like structures are absent in HotSeep-1 cells isolated with hydrogen. These observations suggest that direct electron transfer is a principal mechanism in TAOM, which may also explain the enigmatic functioning and specificity of other methanotrophic ANME-SRB consortia.

  18. Protocol for culturing low density pure rat hippocampal neurons supported by mature mixed neuron cultures.

    Science.gov (United States)

    Yang, Qian; Ke, Yini; Luo, Jianhong; Tang, Yang

    2017-02-01

    primary hippocampal neuron cultures allow for subcellular morphological dissection, easy access to drug treatment and electrophysiology analysis of individual neurons, and is therefore an ideal model for the study of neuron physiology. While neuron and glia mixed cultures are relatively easy to prepare, pure neurons are particular hard to culture at low densities which are suitable for morphology studies. This may be due to a lack of neurotrophic factors such as brain derived neurotrophic factor (BDNF), neurotrophin-3 (NT3) and Glial cell line-derived neurotrophic factor (GDNF). In this study we used a two step protocol in which neuron-glia mixed cultures were initially prepared for maturation to support the growth of young neurons plated at very low densities. Our protocol showed that neurotrophic support resulted in physiologically functional hippocampal neurons with larger cell body, increased neurite length and decreased branching and complexity compared to cultures prepared using a conventional method. Our protocol provides a novel way to culture highly uniformed hippocampal neurons for acquiring high quality, neuron based data. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Rubber gloves biodegradation by a consortium, mixed culture and pure culture isolated from soil samples.

    Science.gov (United States)

    Nawong, Chairat; Umsakul, Kamontam; Sermwittayawong, Natthawan

    2018-02-03

    An increasing production of natural rubber (NR) products has led to major challenges in waste management. In this study, the degradation of rubber latex gloves in a mineral salt medium (MSM) using a bacterial consortium, a mixed culture of the selected bacteria and a pure culture were studied. The highest 18% weight loss of the rubber gloves were detected after incubated with the mixed culture. The increased viable cell counts over incubation time indicated that cells used rubber gloves as sole carbon source leading to the degradation of the polymer. The growth behavior of NR-degrading bacteria on the latex gloves surface was investigated using the scanning electron microscope (SEM). The occurrence of the aldehyde groups in the degradation products was observed by Fourier Transform Infrared Spectroscopy analysis. Rhodococcus pyridinivorans strain F5 gave the highest weight loss of rubber gloves among the isolated strain and posses latex clearing protein encoded by lcp gene. The mixed culture of the selected strains showed the potential in degrading rubber within 30 days and is considered to be used efficiently for rubber product degradation. This is the first report to demonstrate a strong ability to degrade rubber by Rhodococcus pyridinivorans. Copyright © 2018. Published by Elsevier Editora Ltda.

  20. Exploring Race, Culture, and Family in the Identities of Mixed Heritage Students

    Science.gov (United States)

    Johnston-Guerrero, Marc P.; Pecero, Veronica

    2016-01-01

    Family plays an integral role in racial and cultural socialization, yet how mixed heritage students understand the concepts of race and culture in relation to family is unclear. This qualitative study explored the interplay of race, culture, and family in the identity constructions of 25 mixed heritage students. Findings suggest the centrality of…

  1. Detection, isolation, and characterization of acidophilic methanotrophs from Sphagnum mosses.

    Science.gov (United States)

    Kip, Nardy; Ouyang, Wenjing; van Winden, Julia; Raghoebarsing, Ashna; van Niftrik, Laura; Pol, Arjan; Pan, Yao; Bodrossy, Levente; van Donselaar, Elly G; Reichart, Gert-Jan; Jetten, Mike S M; Damsté, Jaap S Sinninghe; Op den Camp, Huub J M

    2011-08-15

    Sphagnum peatlands are important ecosystems in the methane cycle. Methane-oxidizing bacteria in these ecosystems serve as a methane filter and limit methane emissions. Yet little is known about the diversity and identity of the methanotrophs present in and on Sphagnum mosses of peatlands, and only a few isolates are known. The methanotrophic community in Sphagnum mosses, originating from a Dutch peat bog, was investigated using a pmoA microarray. A high biodiversity of both gamma- and alphaproteobacterial methanotrophs was found. With Sphagnum mosses as the inoculum, alpha- and gammaproteobacterial acidophilic methanotrophs were isolated using established and newly designed media. The 16S rRNA, pmoA, pxmA, and mmoX gene sequences showed that the alphaproteobacterial isolates belonged to the Methylocystis and Methylosinus genera. The Methylosinus species isolated are the first acid-tolerant members of this genus. Of the acidophilic gammaproteobacterial strains isolated, strain M5 was affiliated with the Methylomonas genus, and the other strain, M200, may represent a novel genus, most closely related to the genera Methylosoma and Methylovulum. So far, no acidophilic or acid-tolerant methanotrophs in the Gammaproteobacteria class are known. All strains showed the typical features of either type I or II methanotrophs and are, to the best of our knowledge, the first isolated (acidophilic or acid-tolerant) methanotrophs from Sphagnum mosses.

  2. Dimethylamine biodegradation by mixed culture enriched from drinking water biofilter.

    Science.gov (United States)

    Liao, Xiaobin; Chen, Chao; Zhang, Jingxu; Dai, Yu; Zhang, Xiaojian; Xie, Shuguang

    2015-01-01

    Dimethylamine (DMA) is one of the important precursors of drinking water disinfection by-product N-nitrosodimethylamine (NDMA). Reduction of DMA to minimize the formation of carcinogenic NDMA in drinking water is of practical importance. Biodegradation plays a major role in elimination of DMA pollution in the environment, yet information on DMA removal by drinking water biofilter is still lacking. In this study, microcosms with different treatments were constructed to investigate the potential of DMA removal by a mixed culture enriched from a drinking water biofilter and the effects of carbon and nitrogen sources. DMA could be quickly mineralized by the enrichment culture. Amendment of a carbon source, instead of a nitrogen source, had a profound impact on DMA removal. A shift in bacterial community structure was observed with DMA biodegradation, affected by carbon and nitrogen sources. Proteobacteria was the predominant phylum group in DMA-degrading microcosms. Microorganisms from a variety of bacterial genera might be responsible for the rapid DMA mineralization. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Marked heterogeneity in growth characteristics of myoblast clonal cultures and myoblast mixed cultures obtained from the same individual.

    Science.gov (United States)

    Maier, Andrea B; Cohen, Ron; Blom, Joke; van Heemst, Diana; Westendorp, Rudi G J

    2012-01-01

    Sarcopenia is defined as an age-related decrease in skeletal muscle mass and function while adjacent satellite cells are unable to compensate for this loss. However, myoblast cultures can be established even in the presence of sarcopenia. It is yet unknown whether satellite cells from failing muscle in older age are equally affected, as human satellite cells have been assessed using myoblast mixed cultures and not by using myoblast clonal cultures. We questioned to what extent myoblast mixed cultures reflect the in vivo characteristics of single satellite cells from adult skeletal muscle. We established a myoblast mixed culture and three myoblast clonal cultures out of the same muscle biopsy and cultured these cells for 100 days. Replicative capacity and oxidative stress resistance were compared. We found marked heterogeneity between the myoblast clonal cultures that all had a significantly lower replicative capacity when compared to the mixed culture. Replicative capacity of the clonal cultures was inversely related to the β-galactosidase activity after exposure to oxidative stress. Addition of L-carnosine enhanced the remaining replicative capacity in all cultures with a concomitant marginal decrease in β-galactosidase activity. It is concluded that myoblast mixed cultures in vitro do not reflect the marked heterogeneity between single isolated satellite cells. The consequences of the heterogeneity on muscle performance remain to be established. Copyright © 2011 S. Karger AG, Basel.

  4. Starvation and recovery in the deep-sea methanotroph Methyloprofundus sedimenti.

    Science.gov (United States)

    Tavormina, Patricia L; Kellermann, Matthias Y; Antony, Chakkiath Paul; Tocheva, Elitza I; Dalleska, Nathan F; Jensen, Ashley J; Valentine, David L; Hinrichs, Kai-Uwe; Jensen, Grant J; Dubilier, Nicole; Orphan, Victoria J

    2017-01-01

    In the deep ocean, the conversion of methane into derived carbon and energy drives the establishment of diverse faunal communities. Yet specific biological mechanisms underlying the introduction of methane-derived carbon into the food web remain poorly described, due to a lack of cultured representative deep-sea methanotrophic prokaryotes. Here, the response of the deep-sea aerobic methanotroph Methyloprofundus sedimenti to methane starvation and recovery was characterized. By combining lipid analysis, RNA analysis, and electron cryotomography, it was shown that M. sedimenti undergoes discrete cellular shifts in response to methane starvation, including changes in headgroup-specific fatty acid saturation levels, and reductions in cytoplasmic storage granules. Methane starvation is associated with a significant increase in the abundance of gene transcripts pertinent to methane oxidation. Methane reintroduction to starved cells stimulates a rapid, transient extracellular accumulation of methanol, revealing a way in which methane-derived carbon may be routed to community members. This study provides new understanding of methanotrophic responses to methane starvation and recovery, and lays the initial groundwork to develop Methyloprofundus as a model chemosynthesizing bacterium from the deep sea. © 2016 John Wiley & Sons Ltd.

  5. Isolation of methanotrophic bacteria from a london landfill: a preliminary study using molecular and stable isotopic techniques.

    Science.gov (United States)

    Sriskantharajah, S.; Cutting, S.; Lowry, D.; Grassineau, N.; Nisbet, E.

    2003-04-01

    Methane emissions from landfills are an important source of European greenhouse emissions, and could be reduced by a biological management program that used methanotrophs in landfill cover soils. Topsoil samples taken from a London Landfill were incubated on Nitrate Mineral Salts medium in the presence of methane. The resulting colonies were probed for methanotrophic DNA using PCR amplification. DNA from methanotroph positive colonies was cloned and sequenced for identification. Isolates belonging to the genera Methylocaldum, Methylomonas and Methylosinus were detected. Phylogenetic analysis suggests the presence of possible new species. In addition dried samples of the isolates were analysed for their stable carbon isotope (δ 13C) composition. The results were δ 13C values of -27 per mil and -25 per mil for Methylomonas isolates, -35 per mil and -44 per mil for Methylosinus isolates, -58 per mil and -60 per mil for some of the Methylocaldum isolates and -35 per mil and -45 per mil for the others. This isotopic variation is reflected in a phylogenetic tree of the isolates. The differences shown in the δ 13C analysis could be due to differing biochemical properties, and if the technique is further developed, it may be used for rapid identification of bacteria useful in landfill management for reducing methane emissions. The results suggest that useful reductions in methane emissions could be achieved by a careful design of landfill cover to culture methanotrophs.

  6. Nutrition and culture in professional football. A mixed method approach.

    Science.gov (United States)

    Ono, Mutsumi; Kennedy, Eileen; Reeves, Sue; Cronin, Linda

    2012-02-01

    An adequate diet is essential for the optimal performance of professional football (soccer) players. Existing studies have shown that players fail to consume such a diet, without interrogating the reasons for this. The aim of this study was to explore the difficulties professional football players experience in consuming a diet for optimal performance. It utilized a mixed method approach, combining nutritional intake assessment with qualitative interviews, to ascertain both what was consumed and the wider cultural factors that affect consumption. The study found a high variability in individual intake which ranged widely from 2648 to 4606 kcal/day. In addition, the intake of carbohydrate was significantly lower than that recommended. The study revealed that the main food choices for carbohydrate and protein intake were pasta and chicken respectively. Interview results showed the importance of tradition within the world of professional football in structuring the players' approach to nutrition. In addition, the players' personal eating habits that derived from their class and national habitus restricted their food choice by conflicting with the dietary choices promoted within the professional football clubs. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Bioelectrochemical ethanol production through mediated acetate reduction by mixed cultures.

    Science.gov (United States)

    Steinbusch, Kirsten J J; Hamelers, Hubertus V M; Schaap, Joris D; Kampman, Christel; Buisman, Cees J N

    2010-01-01

    Biological acetate reduction with hydrogen is a potential method to convert wet biomass waste into ethanol. Since the ethanol concentration and reaction rates are low, this research studies the feasibility of using an electrode, in stead of hydrogen, as an electron donor for biological acetate reduction in conjunction of an electron mediator. Initially, the effect of three selected mediators on metabolic flows during acetate reduction with hydrogen was explored; subsequently, the best performing mediator was used in a bioelectrochemical system to stimulate acetate reduction at the cathode with mixed cultures at an applied cathode potential of -550 mV. In the batch test, methyl viologen (MV) was found to accelerate ethanol production 6-fold and increased ethanol concentration 2-fold to 13.5 +/- 0.7 mM compared to the control. Additionally, MV inhibited n-butyrate and methane formation, resulting in high ethanol production efficiency (74.6 +/- 6%). In the bioelectrochemical system, MV addition to an inoculated cathode led directly to ethanol production (1.82 mM). Hydrogen was coproduced at the cathode (0.0035 Nm(3) hydrogen m(-2) d(-1)), so it remained unclear whether acetate was reduced to ethanol by electrons supplied by the mediator or by hydrogen. As MV reacted irreversibly at the cathode, ethanol production stopped after 5 days.

  8. Lactic acid production from submerged fermentation of broken rice using undefined mixed culture.

    Science.gov (United States)

    Nunes, Luiza Varela; de Barros Correa, Fabiane Fernanda; de Oliva Neto, Pedro; Mayer, Cassia Roberta Malacrida; Escaramboni, Bruna; Campioni, Tania Sila; de Barros, Natan Roberto; Herculano, Rondinelli Donizetti; Fernández Núñez, Eutimio Gustavo

    2017-04-01

    The present work aimed to characterize and optimize the submerged fermentation of broken rice for lactic acid (LA) production using undefined mixed culture from dewatered activated sludge. A microorganism with amylolytic activity, which also produces LA, Lactobacillus amylovorus, was used as a control to assess the extent of mixed culture on LA yield. Three level full factorial designs were performed to optimize and define the influence of fermentation temperature (20-50 °C), gelatinization time (30-60 min) and broken rice concentration in culture medium (40-80 g L -1 ) on LA production in pure and undefined mixed culture. LA production in mixed culture (9.76 g L -1 ) increased in sixfold respect to pure culture in optimal assessed experimental conditions. The optimal conditions for maximizing LA yield in mixed culture bioprocess were 31 °C temperature, 45 min gelatinization time and 79 g L -1 broken rice concentration in culture medium. This study demonstrated the positive effect of undefined mixed culture from dewatered activated sludge to produce LA from culture medium formulated with broken rice. In addition, this work establishes the basis for an efficient and low-cost bioprocess to manufacture LA from this booming agro-industrial by-product.

  9. A Review of International Cross-Cultural Mixed Messages and Their Implications for Human Resource Development

    Science.gov (United States)

    Altman, Brian A.

    2013-01-01

    This paper presents a literature review on the concept of international cross-cultural mixed messages. Although there is limited literature on this topic, the review suggests that messages from one's home culture and a second culture can result in conflicting expectations for one's own behavior and for the behavior of others. Double bind theory is…

  10. Regulation of methane oxidation in the facultative methanotroph Methylocella silvestris BL2.

    Science.gov (United States)

    Theisen, Andreas R; Ali, M Hanif; Radajewski, Stefan; Dumont, Marc G; Dunfield, Peter F; McDonald, Ian R; Dedysh, Svetlana N; Miguez, Carlos B; Murrell, J Colin

    2005-11-01

    The molecular regulation of methane oxidation in the first fully authenticated facultative methanotroph Methylocella silvestris BL2 was assessed during growth on methane and acetate. Problems of poor growth of Methylocella spp. in small-scale batch culture were overcome by growth in fermentor culture. The genes encoding soluble methane monooxygenase were cloned and sequenced, which revealed that the structural genes for soluble methane monooxygenase, mmoXYBZDC, were adjacent to two genes, mmoR and mmoG, encoding a sigma54 transcriptional activator and a putative GroEL-like chaperone, located downstream (3') of mmoC. Transcriptional analysis revealed that the genes were all cotranscribed from a sigma54-dependent promoter located upstream (5') of mmo X. The transcriptional start site was mapped. Transcriptional analysis of soluble methane monooxygenase genes and expression studies on fermentor grown cultures showed that acetate repressed transcription of sMMO in M. silvestris BL2. The possibility of the presence of a particulate, membrane-bound methane monooxygenase enzyme in M. silvestris BL2 and the copper-mediated regulation of soluble methane monooxygenase was investigated. Both were shown to be absent. A promoter probe vector was constructed and used to assay transcription of the promoter of the soluble methane monoxygenase genes of M. silvestris BL2 grown under various conditions and with different substrates. These data represent the first insights into the molecular physiology of a facultative methanotroph.

  11. Bioremediation of MGP soils with mixed fungal and bacterial cultures

    International Nuclear Information System (INIS)

    Lee, C.J.B.; Fletcher, M.A.; Avila, O.I.; Munnecke, D.M.; Callanan, J.; Yunker, S.

    1995-01-01

    This culture selection study examines the degradation of polycyclic automatic hydrocarbon (PAH) by a number of brown- and white-rot fungi and bacterial cultures for the treatment of coal tar wastes. Cultures were screened for naphthalene degradation in shake flasks, and selected organisms were then examined for their ability to degrade a mixture of PAHs in aqueous culture. PAH degradation in the presence of the surfactant, TWEEN 80, was examined for some cultures. Many of the organisms were observed to be resistant to greater than 10 mg/L free cyanide. Solid substrate growth conditions were optimized for the selected fungal cultures in preparation for manufactured gas plant (MGP) soil microcosm experiments. The fungi generally produced more biomass under conditions of acidic to neutral pH, incubation at 30 C with 90% moisture saturation, and with granulated corncobs or alfalfa pellets supplied as a lignocellulosic substrate. Of the cultures screened, nine fungal cultures were selected based on their ability to degrade at least 40% of naphthalene, fluorene, or benzo(a)pyrene in 2 weeks or less. A bacterial culture capable of degrading 30 mg/L of naphthalene in 1 week was also selected, and the cultures were examined further in PAH-degradation studies in contaminated soils

  12. Enhanced kefiran production by mixed culture of Lactobacillus kefiranofaciens and Saccharomyces cerevisiae.

    Science.gov (United States)

    Cheirsilp, Benjamas; Shimizu, Hiroshi; Shioya, Suteaki

    2003-01-09

    In a batch mixed culture of Lactobacillus kefiranofaciens and Saccharomyces cerevisiae, which could assimilate lactic acid, cell growth and kefiran production rates of L. kefiranofaciens significantly increased, compared with those in pure cultures. The kefiran production rate was 36 mg l(-1) h(-1) in the mixed culture under the anaerobic condition, which was greater than that in the pure culture (24 mg l(-1) h(-1)). Under the aerobic condition, a more intensive interaction between these two strains was observed and higher kefiran production rate (44 mg l(-1) h(-1)) was obtained compared with that under the anaerobic condition. Kefiran production was further enhanced by an addition of fresh medium in the fed-batch mixed culture. In the fed-batch mixed culture, a final kefiran concentration of 5.41 g l(-1) was achieved at 87 h, thereby attaining the highest productivity at 62 mg l(-1) h(-1). Simulation study considered the reduction of lactic acid in pure culture was performed to estimate the additional effect of coculture with S. cerevisiae. Slightly higher cell growth and kefiran production rates in the mixed culture than those expected from pure culture by simulation were observed. These results suggest that coculture of L. kefiranofaciens and S. cerevisiae not only reduces the lactic acid concentration by consumption but also stimulates cell growth and kefiran production of L. kefiranofaciens.

  13. Mixed cultures of Kimchi lactic acid bacteria show increased cell ...

    African Journals Online (AJOL)

    ufuoma

    production and amino acid release among the tested bacteria. W. koreensis 521 ... production of fermented food products, such as yogurt, cheese, sauerkraut and ... habits, stress and excessive dieting (Kapka-Skrzypczak et al., 2012). Mixed ...

  14. Selected Aspects of Cultural Differences and their Influence on the International Marketing Mix

    OpenAIRE

    Svendsen, Anne Sakseide

    2010-01-01

    Culture is an important business element which can make the difference between success and failure for businesses that will expand abroad. The differences between two cultures do not have to vary to a large extent, but they still have to be considered. Hence knowledge about culture plays an important role in a company's decision making process. This master thesis is focused on selected aspects of cultural differences and their influence on the international marketing mix. The first part of th...

  15. Interactions between Lactobacillus kefiranofaciens and Saccharomyces cerevisiae in mixed culture for kefiran production.

    Science.gov (United States)

    Cheirsilp, Benjamas; Shoji, Hirofumi; Shimizu, Hiroshi; Shioya, Suteaki

    2003-01-01

    Since a positive effect on the growth and kefiran production of Lactobacillus kefiranofaciens was observed in a mixed culture with Saccharomyces cerevisiae, the elucidation of the interactions between L. kefiranofaciens and S. cerevisiae may lead to higher productivity. Hence, the microbial interaction of each strain was investigated. Apart from the positive effect of a reduction in the amount of lactic acid by S. cerevisiae, a positive effect of S. cerevisiae on the growth and kefiran production of L. kefiranofaciens in a mixed culture was observed. Various experiments were carried out to study this effect. In this study, the observed increase in capsular kefiran in a mixed culture with inactivated S. cerevisiae correlated well to that in an anaerobic mixed culture. Differences in capsular kefiran production were observed for different initial S. cerevisiae concentrations under anaerobic conditions. From these fermentation results, it was concluded that the physical contact with S. cerevisiae mainly enhanced the capsular kefiran production of L. kefiranofaciens in a mixed culture. Therefore, in an anaerobic mixed culture, this direct contact resulted in higher capsular kefiran production than that in pure culture.

  16. The maximum specific hydrogen-producing activity of anaerobic mixed cultures: definition and determination.

    Science.gov (United States)

    Mu, Yang; Yang, Hou-Yun; Wang, Ya-Zhou; He, Chuan-Shu; Zhao, Quan-Bao; Wang, Yi; Yu, Han-Qing

    2014-06-10

    Fermentative hydrogen production from wastes has many advantages compared to various chemical methods. Methodology for characterizing the hydrogen-producing activity of anaerobic mixed cultures is essential for monitoring reactor operation in fermentative hydrogen production, however there is lack of such kind of standardized methodologies. In the present study, a new index, i.e., the maximum specific hydrogen-producing activity (SHAm) of anaerobic mixed cultures, was proposed, and consequently a reliable and simple method, named SHAm test, was developed to determine it. Furthermore, the influences of various parameters on the SHAm value determination of anaerobic mixed cultures were evaluated. Additionally, this SHAm assay was tested for different types of substrates and bacterial inocula. Our results demonstrate that this novel SHAm assay was a rapid, accurate and simple methodology for determining the hydrogen-producing activity of anaerobic mixed cultures. Thus, application of this approach is beneficial to establishing a stable anaerobic hydrogen-producing system.

  17. The maximum specific hydrogen-producing activity of anaerobic mixed cultures: definition and determination

    Science.gov (United States)

    Mu, Yang; Yang, Hou-Yun; Wang, Ya-Zhou; He, Chuan-Shu; Zhao, Quan-Bao; Wang, Yi; Yu, Han-Qing

    2014-06-01

    Fermentative hydrogen production from wastes has many advantages compared to various chemical methods. Methodology for characterizing the hydrogen-producing activity of anaerobic mixed cultures is essential for monitoring reactor operation in fermentative hydrogen production, however there is lack of such kind of standardized methodologies. In the present study, a new index, i.e., the maximum specific hydrogen-producing activity (SHAm) of anaerobic mixed cultures, was proposed, and consequently a reliable and simple method, named SHAm test, was developed to determine it. Furthermore, the influences of various parameters on the SHAm value determination of anaerobic mixed cultures were evaluated. Additionally, this SHAm assay was tested for different types of substrates and bacterial inocula. Our results demonstrate that this novel SHAm assay was a rapid, accurate and simple methodology for determining the hydrogen-producing activity of anaerobic mixed cultures. Thus, application of this approach is beneficial to establishing a stable anaerobic hydrogen-producing system.

  18. Evidence of co-metabolic bentazone transformation by methanotrophic enrichment from a groundwater-fed rapid sand filter

    DEFF Research Database (Denmark)

    Hedegaard, Mathilde Jørgensen; Deliniere, Hélène; Prasse, Carsten

    2018-01-01

    from 58 to 158, well within the range for methanotrophic co-metabolic degradation of trace contaminants calculated from the literature, with normalized substrate preferences varying from 3 to 400. High-resolution mass spectrometry revealed formation of the transformation products (TPs) 6-OH, 8-OH......The herbicide bentazone is recalcitrant in aquifers and is therefore frequently detected in wells used for drinking water production. However, bentazone degradation has been observed in filter sand from a rapid sand filter at a waterworks with methane-rich groundwater. Here, the association between...... and bentazone at concentrations below 2 mg/L showed methanotrophic co-metabolic bentazone transformation: The culture removed 53% of the bentazone in 21 days in presence of 5 mg/L of methane, while only 31% was removed in absence of methane. Addition of acetylene inhibited methane oxidation and stopped...

  19. Influence of culture on decisions in marketing mix in the international context

    OpenAIRE

    Constantin Sasu

    2006-01-01

    This article describes the impact of cultural dimensions on the four marketing mix variables (product, price, distribution, promotion) The cultural dimensions will be treated as independent variables affecting the behaviour of marketing mix variables which are seen as dependent variables. This in turn will provide the opportunity to assess the state of the art in this area both from the viewpoint of marketing practitioners, and of researchers. Concluding comments cover research issues and man...

  20. Addition of exogenous cytokines in mixed lymphocyte culture for selecting related donors for bone marrow transplantation

    Directory of Open Access Journals (Sweden)

    Jeane Eliete Laguila Visentainer

    Full Text Available CONTEXT: Mixed lymphocyte culturing has led to conflicting opinions regarding the selection of donors for bone marrow transplantation. The association between a positive mixed lymphocyte culture and the development of graft-versus-host disease (GVHD is unclear. The use of exogenous cytokines in mixed lymphocyte cultures could be an alternative for increasing the sensitivity of culture tests. OBJECTIVE: To increase the sensitivity of mixed lymphocyte cultures between donor and recipient human leukocyte antigen (HLA identical siblings, using exogenous cytokines, in order to predict post-transplantation GVHD and/or rejection. TYPE OF STUDY: Prospective study. SETTING: Bone Marrow Transplantation Unit, Universidade Estadual de Campinas. PARTICIPANTS: Seventeen patients with hematological malignancies and their respective donors selected for bone marrow transplantation procedures. PROCEDURES: Standard and modified mixed lymphocyte culturing by cytokine supplementation was carried out using donor and recipient cells typed for HLA. MAIN MEASUREMENTS: Autologous and allogenic responses in mixed lymphocyte cultures after the addition of IL-4 or IL-2. RESULTS: In comparison with the standard method, average responses in the modified mixed lymphocyte cultures increased by a factor of 2.0 using IL-4 (p < 0.001 and 6.4 using IL-2 (p < 0.001, for autologous donor culture responses. For donor-versus-recipient culture responses, the increase was by a factor of 1.9 using IL-4 (p < 0.001 and 4.1 using IL-2 (p < 0.001. For donor-versus-unrelated culture responses, no significant increase was observed using IL-4, and a mean response inhibition of 20% was observed using IL-2 (p < 0.001. Neither of the cytokines produced a significant difference in the unrelated control versus recipient cell responses. CONCLUSION: IL-4 supplementation was the best for increasing the mixed lymphocyte culture sensitivity. However, IL-4 also increased autologous responses, albeit less

  1. Perceptions of Organizational Culture of a Multi-Campus Community College District: Mixed Methods in Concert

    Science.gov (United States)

    Kuster Dale, Kimberly

    2012-01-01

    This concurrent, mixed-methods case study analyzed perceptions of current and preferred organizational culture within a rural, multi-campus community college district. This phenomenon was examined by analyzing and comparing data collected by surveying all full-time employees utilizing the Organizational Culture Assessment Instrument (OCAI) and…

  2. Biodegradation of used motor oil by single and mixed cultures of ...

    African Journals Online (AJOL)

    This study was carried out to evaluate the potential of single and mixed cultures of Nostoc hatei and Synechocystis aquatilis in the biodegradation of 10% used motor oil. The rates of biodegradation of the oil were studied for a period of 21 days under laboratory conditions. Single cultures of N. hatei performed best in the ...

  3. Evaluation of a PCR for detection of Actinobacillus pleuropneumoniae in mixed bacterial cultures from tonsils

    DEFF Research Database (Denmark)

    Gram, T.; Ahrens, Peter; Nielsen, J.P.

    1996-01-01

    strains of A. lignieresii. The lower detection limit of the PCR test was 10(3) A. pleuropneumoniae CFU/PCR test tube and was not affected by addition of 10(6) E. coli CFU/PCR test tube. Mixed bacterial cultures from tonsils of 101 pigs from 9 different herds were tested by culture and by PCR using four...

  4. Mixed cultures of Kimchi lactic acid bacteria show increased cell ...

    African Journals Online (AJOL)

    ufuoma

    anaerobic organisms that are highly resistant to salts. Probiotic cultures for use in ... kimchi have a superior ability to decompose and utilize nutrients, and show ... citrate, 5 g sodium acetate, 1 g Tween, 2 g K2HPO4, 0.2 g. MgSO4•7H2O, 0.2 g ...

  5. Direct delignification of untreated bark chips with mixed cultures of bacteria. [Bacillus and Cellulomonas strains

    Energy Technology Data Exchange (ETDEWEB)

    Deschamps, A M; Gillie, J P; Lebeault, J M

    1981-01-01

    Delignification of pine bark chips was observed after about 35 days when they were the sole carbon source in mixed liquid cultures of cellulolytic and lignin degrading strains of Bacillus and Cellulomonas. No delignification was observed in pure cultures. Free tannins liberated from the chips were also degraded in most of the cultures. The necessity of combining a cellulolytic and lignin degrading bacterial strain to obtain delignification is discussed. (Refs. 25).

  6. Detection, Isolation, and Characterization of Acidophilic Methanotrophs from

    NARCIS (Netherlands)

    Kip, N.; Ouyang, W.J.; van Winden, J.; Raghoebarsing, A.; van Niftrik, L.; Pol, A.; Pan, Y.; Bodrossy, L.; van Donselaar, E.G.; Reichart, G.J.; Jetten, M.S.M.; Sinninghe Damsté, J.S.; Op den Camp, H.J.M.

    2011-01-01

    Sphagnum peatlands are important ecosystems in the methane cycle. Methane-oxidizing bacteria in these ecosystems serve as a methane filter and limit methane emissions. Yet little is known about the diversity and identity of the methanotrophs present in and on Sphagnum mosses of peatlands, and only a

  7. Facultative methanotrophs are abundant at terrestrial natural gas seeps.

    Science.gov (United States)

    Farhan Ul Haque, Muhammad; Crombie, Andrew T; Ensminger, Scott A; Baciu, Calin; Murrell, J Colin

    2018-06-28

    Natural gas contains methane and the gaseous alkanes ethane, propane and butane, which collectively influence atmospheric chemistry and cause global warming. Methane-oxidising bacteria, methanotrophs, are crucial in mitigating emissions of methane as they oxidise most of the methane produced in soils and the subsurface before it reaches the atmosphere. Methanotrophs are usually obligate, i.e. grow only on methane and not on longer chain alkanes. Bacteria that grow on the other gaseous alkanes in natural gas such as propane have also been characterised, but they do not grow on methane. Recently, it was shown that the facultative methanotroph Methylocella silvestris grew on ethane and propane, other components of natural gas, in addition to methane. Therefore, we hypothesised that Methylocella may be prevalent at natural gas seeps and might play a major role in consuming all components of this potent greenhouse gas mixture before it is released to the atmosphere. Environments known to be exposed to biogenic methane emissions or thermogenic natural gas seeps were surveyed for methanotrophs. 16S rRNA gene amplicon sequencing revealed that Methylocella were the most abundant methanotrophs in natural gas seep environments. New Methylocella-specific molecular tools targeting mmoX (encoding the soluble methane monooxygenase) by PCR and Illumina amplicon sequencing were designed and used to investigate various sites. Functional gene-based assays confirmed that Methylocella were present in all of the natural gas seep sites tested here. This might be due to its ability to use methane and other short chain alkane components of natural gas. We also observed the abundance of Methylocella in other environments exposed to biogenic methane, suggesting that Methylocella has been overlooked in the past as previous ecological studies of methanotrophs often used pmoA (encoding the alpha subunit of particulate methane monooxygenase) as a marker gene. New biomolecular tools designed in

  8. In situ bioremediation of trichloroethylene-contaminated water by a resting-cell methanotrophic microbial filter

    International Nuclear Information System (INIS)

    Taylor, R.T.; Duba, A.G.; Durham, W.B.; Hanna, M.L.; Jackson, K.J.; Jovanovich, M.C.; Knapp, R.B.; Knezovich, J.P.; Shah, N.N.; Shonnard, D.R.; Wijesinghe, A.M.

    1992-10-01

    The Lawrence Livermore National Laboratory is testing and developing an in situ microbial filter technology for remediating migrating subsurface plumes contaminated with low concentrations of trichloroethylene (TCE). Their current focus is the establishment of a replenishable bioactive zone (catalytic filter) along expanding plume boundaries by the Injection of a representative methanotrophic bacterium, Methylosinus trichosporium OB3b. We have successfully demonstrated this microbial filter strategy using emplaced, attached resting cells (no methane additions) in a 1.1-m flow-through test bed loaded with water-saturated sand. Two separate 24 h pulses of TCE (109 ppb and 85 ppb), one week apart, were pumped through the system at a flow velocity of 1.5 cm/h; no TCE (<0.5 ppb) was detected on the downstream side of the microbial filter. Subsequent excavation of the wet sand confirmed the existence of a TCE-bioactive zone 19 days after it had been created. An enhanced longevity of the cellular, soluble-form methane monooxygenase produced by this methanotroph Is a result of our laboratory bioreactor culturing conditions. Additional experiments with cells in sealed vials and emplaced in the 1.1-m test bed yielded a high resting-cell finite TCE biotransformation capacity of ∼ 0.25 mg per mg of bacteria; this is suitable for a planned sand-filled trench field demonstration at a Lawrence Livermore National Laboratory site

  9. Efficient removal of disperse dye by mixed culture of ganoderma lucidum and coriolus versicolor

    International Nuclear Information System (INIS)

    Sadaf, S.; Bhatti, H.N.; Bibi, I.

    2013-01-01

    In the current study, an attempt was made to check the potential of aerobic mixed culture of two indigenous white rot fungi for the decolorization of different disperse dyes in batch culture mode and optimization of different conditions to enhance the biotransformation of dyes. Initial screening trial with six disperse dyes, viz. (Foron Yellow RD5GL, Foron Red RDRBLS, Foron Rubine RDGFL, Foron Black RD3GRN, Foron Blue RDGLN and Foron Turquoise SBLN), was carried out using mixed culture of Ganoderma lucidum and Coriolus versicolor. From all the tested dyes, the mixed culture showed better removal efficiency (93 %) with Foron Turquoise SBLN dye after 8 days of incubation period as compared to other tested dyes. Enhanced color removal (98 %) was observed when the medium was amended by ammonium tartarate, maltose, MnSO/sub 4/ at pH 4.5 and 30 degree C with 2 mL fungal culture during 2nd day of incubation period. Enzyme profile showed that the mixed culture produced three liginolytic enzymes like lignin peroxidase (LiP), manganase peroxidase (MnP) and laccase but MnP was found to be the major enzyme. The results indicated that white rot fungi (WRF) could be used to treat wastewater containing disperse dyes. (author)

  10. Mixing against culture vs mixing against nature: ontologization of prohibited interethnic relationships.

    Science.gov (United States)

    Roncarati, Alessandra; Pérez, Juan A; Ravenna, Marcella; Navarro-Pertusa, Esperanza

    2009-02-01

    In this paper, we develop the theory of ontologization: Social representations that prevent members of minority and majority groups who are living in contact with each other to mingle. The process of ontologization consists of separating some humans from their own species, and anchoring them in another environment, that of an animal, for example. We propose that underlying the famous slogan "equal but separate" is the social representation of interracial mixing as a "counter-nature" phenomenon. It is predicted that a sexual relationship between people of different "races" leads to a greater degree of ontologization, and, as such, this miscegenation will be explained in terms of biologistic thinking, like an instinctive nature or atavistic animal impulse. An experiment (N = 360) features the case of a woman who, though already in a stable relationship, is unfaithful to her partner. In a 2×3 factor design, the ethnic-national identity of this woman (in-group: Spanish/Italian vs out-group: Senegalese) and the ethnic-national identity of her lovers (in-group: Spanish/Italian vs out-group: Rumanian vs out-group: Senegalese) were manipulated. In general, results fit the hypothesis of ontologization in interracial conditions better, rather than the customary in-group favouritism and/or out-group discrimination bias. We then go on to discuss the way in which a biologistic way of thinking enables a differentiation at the human level, in terms of culture groups and nature groups, in "races," so that an interracial sexual relationship is seen as evidence of a wild and irrepressible impulse, which stigmatizes the people involved in these relationships. This research was supported by the Italian/Spanish Integrated Action Program HI2004_0241 and the Spanish Ministerio de Ciencia y Tecnología BSO2003-00476/PSCE. Dans cet article, nous développons la théorie de l'ontologisation: des représentations sociales qui empêchent les membres des groupes minoritaire et majoritaire

  11. Formation of industrial mixed culture biofilm in chlorophenol cultivated medium of microbial fuel cell

    Science.gov (United States)

    Hassan, Huzairy; Jin, Bo; Dai, Sheng; Ngau, Cornelius

    2016-11-01

    The formation of microbial biofilm while maintaining the electricity output is a challenging topic in microbial fuel cell (MFC) studies. This MFC critical factor becomes more significant when handling with industrial wastewater which normally contains refractory and toxic compounds. This study explores the formation of industrial mixed culture biofilm in chlorophenol cultivated medium through observing and characterizing microscopically its establishment on MFC anode surface. The mixed culture was found to develop its biofilm on the anode surface in the chlorophenol environment and established its maturity and dispersal stages with concurrent electricity generation and phenolic degradation. The mixed culture biofilm engaged the electron transfer roles in MFC by generating current density of 1.4 mA/m2 and removing 53 % of 2,4-dichlorophenol. The results support further research especially on hazardous wastewater treatment using a benign and sustainable method.

  12. Continuous production of ethanol from hexoses and pentoses using immobilized mixed cultures of Escherichia coli strains

    Science.gov (United States)

    Unrean, Pornkamol; Srienc, Friedrich

    2010-01-01

    We have developed highly efficient ethanologenic E. coli strains that selectively consume pentoses and/or hexoses. Mixed cultures of these strains can be used to selectively adjust the sugar utilization kinetics in ethanol fermentations. Based on the kinetics of sugar utilization, we have designed and implemented an immobilized cell system for the optimized continuous conversion of sugars into ethanol. The results confirm that immobilized mixed cultures support a simultaneous conversion of hexoses and pentoses into ethanol at high yield and at a faster rate than immobilized homogenous cells. Continuous ethanol production has been maintained for several weeks at high productivity with near complete sugar utilization. The control of sugar utilization using immobilized mixed cultures can be adapted to any composition of hexoses and pentoses by adjusting the strain distribution of immobilized cells. The approach, therefore, holds promise for ethanol fermentation from lignocellulosic hydrolysates where the feedstock varies in sugar composition. PMID:20699108

  13. Different Abilities of Eight Mixed Cultures of Methane-oxidizing Bacteria to Degrade TCE

    DEFF Research Database (Denmark)

    Broholm, Kim; Christensen, Thomas Højlund; Jensen, Bjørn K.

    1993-01-01

    The ability of eight mixed cultures of methane-oxidizing bacteria to degrade trichloroethylene (TCE) was examined in laboratory batch experiments. This is one of the first reported works studying TCE degradation by mixed cultures of methane-oxidizing bacteria at 10°C, a common temperature for soils...... methanol, but only for a limited time period of about 5 days. Several explanations for the discontinued degradation of TCE are given. An experiment carried out to re-activate the methane-oxidizing bacteria after 8 days of growth on methanol by adding methane did not immediately result in degradation...... of methane and TCE. During the first 10–15 days after the addition of methane a significant degradation of methane and a minor degradation of TCE were observed. This experiment revealed that the ability of mixed cultures of methane-oxidizing bacteria to degrade TCE varied significantly even though...

  14. Development of a PCR test for identification of Haemophilus somnus in pure and mixed cultures

    DEFF Research Database (Denmark)

    Angen, Øystein; Ahrens, Peter; Tegtmeier, Conny

    1998-01-01

    a single colony of H. somnus in the presence of 10(9) CFU of P. multocida even after 2 days of incubation. In conclusion, the present PCR test has been shown to represent a specific test for identification of H. somnus both in pure and mixed cultures. It represents a quick, sensitive and reliable method...... rise to an amplicon in the PCR test. The performance of the test on mixed cultures was evaluated by adding P. multocida to serial dilutions of H. somnus and incubating the agarplates for 1 and 2 days. This showed that the PCR test applied to the harvest from an agarplate can be expected to detect...

  15. Determination of DB10B values of single and mixed cultures of ...

    African Journals Online (AJOL)

    The survi-ving fraction of isolates decreased with increased irradiation doses. DB10B values of E. coli, S. aureus and S. parat-hyphi B were respectively 0.27, 0.33 and 0.44 kGy when inoculated as single cultures, and 0.24, 0.28 and 0.32 kGy respectively when inoculated as mixed cultures. DB10B values were lower for ...

  16. The oxidative TCA cycle operates during methanotrophic growth of the Type I methanotroph Methylomicrobium buryatense 5GB1.

    Science.gov (United States)

    Fu, Yanfen; Li, Yi; Lidstrom, Mary

    2017-07-01

    Methanotrophs are a group of bacteria that use methane as sole carbon and energy source. Type I methanotrophs are gamma-proteobacterial methanotrophs using the ribulose monophosphate cycle (RuMP) cycle for methane assimilation. In order to facilitate metabolic engineering in the industrially promising Type I methanotroph Methylomicrobium buryatense 5GB1, flux analysis of cellular metabolism is needed and 13 C tracer analysis is a foundational tool for such work. This biological system has a single-carbon input and a special network topology that together pose challenges to the current well-established methodology for 13 C tracer analysis using a multi-carbon input such as glucose, and to date, no 13 C tracer analysis of flux in a Type I methanotroph has been reported. In this study, we showed that by monitoring labeling patterns of several key intermediate metabolites in core metabolism, it is possible to quantitate the relative flux ratios for important branch points, such as the malate node. In addition, it is possible to assess the operation of the TCA cycle, which has been thought to be incomplete in Type I methanotrophs. Surprisingly, our analysis provides direct evidence of a complete, oxidative TCA cycle operating in M. buryatense 5GB1 using methane as sole carbon and energy substrate, contributing about 45% of the total flux for de novo malate production. Combined with mutant analysis, this method was able to identify fumA (METBUDRAFT_1453/MBURv2__60244) as the primary fumarase involved in the oxidative TCA cycle, among 2 predicted fumarases, supported by 13 C tracer analysis on both fumA and fumC single knockouts. Interrupting the oxidative TCA cycle leads to a severe growth defect, suggesting that the oxidative TCA cycle functions to not only provide precursors for de novo biomass synthesis, but also to provide reducing power to the system. This information provides new opportunities for metabolic engineering of M. buryatense for the production of

  17. Differential Transcriptional Activation of Genes Encoding Soluble Methane Monooxygenase in a Facultative Versus an Obligate Methanotroph

    OpenAIRE

    Angela V. Smirnova; Peter F. Dunfield

    2018-01-01

    Methanotrophs are a specialized group of bacteria that can utilize methane (CH4) as a sole energy source. A key enzyme responsible for methane oxidation is methane monooxygenase (MMO), of either a soluble, cytoplasmic type (sMMO), or a particulate, membrane-bound type (pMMO). Methylocella silvestris BL2 and Methyloferula stellata AR4 are closely related methanotroph species that oxidize methane via sMMO only. However, Methyloferula stellata is an obligate methanotroph, while Methylocella silv...

  18. Recurrence and frequency of disturbance have cumulative effect on methanotrophic activity, abundance, and community structure.

    Directory of Open Access Journals (Sweden)

    Adrian eHo

    2016-01-01

    Full Text Available Alternate prolonged drought and heavy rainfall is predicted to intensify with global warming. Desiccation-rewetting events alter the soil quality and nutrient concentrations which drive microbial-mediated processes, including methane oxidation, a key biogeochemical process catalyzed by methanotrophic bacteria. Although aerobic methanotrophs showed remarkable resilience to a suite of physical disturbances induced as a single event, their resilience to recurring disturbances is less known. Here, using a rice field soil in a microcosm study, we determined whether recurrence and frequency of desiccation-rewetting impose an accumulating effect on the methanotrophic activity. The response of key aerobic methanotroph subgroups (type Ia, Ib, and II were monitored using qPCR assays, and was supported by a t-RFLP analysis. The methanotrophic activity was resilient to recurring desiccation-rewetting, but increasing the frequency of the disturbance by two-fold significantly decreased methane uptake rate. Both the qPCR and t-RFLP analyses were congruent, showing the dominance of type Ia/Ib methanotrophs prior to disturbance, and after disturbance, the recovering community was predominantly comprised of type Ia (Methylobacter methanotrophs. Both type Ib and type II (Methylosinus/Methylocystis methanotrophs were adversely affected by the disturbance, but type II methanotrophs showed recovery over time, indicating relatively higher resilience to the disturbance. This revealed distinct, yet unrecognized traits among the methanotroph community members. Our results show that recurring desiccation-rewetting before a recovery in community abundance had an accumulated effect, compromising methanotrophic activity. While methanotrophs may recover well following sporadic disturbances, their resilience may reach a ‘tipping point’ where activity no longer recovered if disturbance persists and increase in frequency.

  19. Separation of allelopathy from resource competition using rice/barnyardgrass mixed-cultures.

    Directory of Open Access Journals (Sweden)

    Hai Bin He

    Full Text Available Plant-plant interference is the combined effect of allelopathy, resource competition, and many other factors. Separating allelopathy from resource competition is almost impossible in natural systems but it is important to evaluate the relative contribution of each of the two mechanisms on plant interference. Research on allelopathy in natural and cultivated plant communities has been hindered in the absence of a reliable method that can separate allelopathic effect from resource competition. In this paper, the interactions between allelopathic rice accession PI312777, non-allelopathic rice accession Lemont and barnyardgrass were explored respectively by using a target (rice-neighbor (barnyardgrass mixed-culture in hydroponic system. The relative competitive intensity (RCI, the relative neighbor effect (RNE and the competitive ratio (CR were used to quantify the intensity of competition between each of the two different potentially allelopathic rice accessions and barnyardgrass. Use of hydroponic culture system enabled us to exclude any uncontrolled factors that might operate in the soil and we were able to separate allelopathy from resource competition between each rice accession and barnyardgrass. The RCI and RNE values showed that the plant-plant interaction was positive (facilitation for PI312777 but that was negative (competition for Lemont and barnyardgrass in rice/barnyardgrass mixed-cultures. The CR values showed that one PI312777 plant was more competitive than 2 barnyardgrass plants. The allelopathic effects of PI312777 were much more intense than the resource competition in rice/barnyardgrass mixed cultures. The reverse was true for Lemont. These results demonstrate that the allelopathic effect of PI312777 was predominant in rice/barnyardgrass mixed-cultures. The most significant result of our study is the discovery of an experimental design, target-neighbor mixed-culture in combination with competition indices, can successfully

  20. Methanotrophic bacteria in oilsands tailings ponds of northern Alberta

    Science.gov (United States)

    Saidi-Mehrabad, Alireza; He, Zhiguo; Tamas, Ivica; Sharp, Christine E; Brady, Allyson L; Rochman, Fauziah F; Bodrossy, Levente; Abell, Guy CJ; Penner, Tara; Dong, Xiaoli; Sensen, Christoph W; Dunfield, Peter F

    2013-01-01

    We investigated methanotrophic bacteria in slightly alkaline surface water (pH 7.4–8.7) of oilsands tailings ponds in Fort McMurray, Canada. These large lakes (up to 10 km2) contain water, silt, clay and residual hydrocarbons that are not recovered in oilsands mining. They are primarily anoxic and produce methane but have an aerobic surface layer. Aerobic methane oxidation was measured in the surface water at rates up to 152 nmol CH4 ml−1 water d−1. Microbial diversity was investigated via pyrotag sequencing of amplified 16S rRNA genes, as well as by analysis of methanotroph-specific pmoA genes using both pyrosequencing and microarray analysis. The predominantly detected methanotroph in surface waters at all sampling times was an uncultured species related to the gammaproteobacterial genus Methylocaldum, although a few other methanotrophs were also detected, including Methylomonas spp. Active species were identified via 13CH4 stable isotope probing (SIP) of DNA, combined with pyrotag sequencing and shotgun metagenomic sequencing of heavy 13C-DNA. The SIP-PCR results demonstrated that the Methylocaldum and Methylomonas spp. actively consumed methane in fresh tailings pond water. Metagenomic analysis of DNA from the heavy SIP fraction verified the PCR-based results and identified additional pmoA genes not detected via PCR. The metagenome indicated that the overall methylotrophic community possessed known pathways for formaldehyde oxidation, carbon fixation and detoxification of nitrogenous compounds but appeared to possess only particulate methane monooxygenase not soluble methane monooxygenase. PMID:23254511

  1. Environmental distribution and abundance of the facultative methanotroph Methylocella

    OpenAIRE

    Rahman, Md Tanvir; Crombie, Andrew; Chen, Yin; Stralis-Pavese, Nancy; Bodrossy, Levente; Meir, Patrick; McNamara, Niall P; Murrell, J Colin

    2010-01-01

    Methylocella spp. are facultative methanotrophs, which are able to grow not only on methane but also on multicarbon substrates such as acetate, pyruvate or malate. Methylocella spp. were previously thought to be restricted to acidic soils such as peatlands, in which they may have a key role in methane oxidation. There is little information on the abundance and distribution of Methylocella spp. in the environment. New primers were designed, and a real-time quantitative PCR method was developed...

  2. Biological Methanol Production by a Type II Methanotroph Methylocystis bryophila.

    Science.gov (United States)

    Patel, Sanjay K S; Mardina, Primata; Kim, Sang-Yong; Lee, Jung-Kul; Kim, In-Won

    2016-04-28

    Methane (CH₄) is the most abundant component in natural gas. To reduce its harmful environmental effect as a greenhouse gas, CH₄ can be utilized as a low-cost feed for the synthesis of methanol by methanotrophs. In this study, several methanotrophs were examined for their ability to produce methanol from CH₄; including Methylocella silvestris, Methylocystis bryophila, Methyloferula stellata, and Methylomonas methanica. Among these methanotrophs, M. bryophila exhibited the highest methanol production. The optimum process parameters aided in significant enhancement of methanol production up to 4.63 mM. Maximum methanol production was observed at pH 6.8, 30°C, 175 rpm, 100 mM phosphate buffer, 50 mM MgCl₂ as a methanol dehydrogenase inhibitor, 50% CH₄ concentration, 24 h of incubation, and 9 mg of dry cell mass ml(-1) inoculum load, respectively. Optimization of the process parameters, screening of methanol dehydrogenase inhibitors, and supplementation with formate resulted in significant improvements in methanol production using M. bryophila. This report suggests, for the first time, the potential of using M. bryophila for industrial methanol production from CH₄.

  3. Feasibility of atmospheric methane removal using methanotrophic biotrickling filters.

    Science.gov (United States)

    Yoon, Sukhwan; Carey, Jeffrey N; Semrau, Jeremy D

    2009-07-01

    Methane is a potent greenhouse gas with a global warming potential ~23 times that of carbon dioxide. Here, we describe the modeling of a biotrickling filtration system composed of methane-consuming bacteria, i.e., methanotrophs, to assess the utility of these systems in removing methane from the atmosphere. Model results indicate that assuming the global average atmospheric concentration of methane, 1.7 ppmv, methane removal is ineffective using these methanotrophic biofilters as the methane concentration is too low to enable cell survival. If the concentration is increased to 500-6,000 ppmv, however, similar to that found above landfills and in concentrated animal feeding operations (factory farms), 4.98-35.7 tons of methane can be removed per biofilter per year assuming biotrickling filters of typical size (3.66 m in diameter and 11.5 m in height). Using reported ranges of capital, operational, and maintenance costs, the cost of the equivalent ton of CO(2) removal using these systems is $90-$910 ($2,070-$20,900 per ton of methane), depending on the influent concentration of methane and if heating is required. The use of methanotrophic biofilters for controlling methane emissions is technically feasible and, provided that either the costs of biofilter construction and operation are reduced or the value of CO(2) credits is increased, can also be economically attractive.

  4. Enhanced hydrogen and 1,3-propanediol production from glycerol by fermentation using mixed cultures

    KAUST Repository

    Selembo, Priscilla A.; Perez, Joe M.; Lloyd, Wallis A.; Logan, Bruce E.

    2009-01-01

    The conversion of glycerol into high value products, such as hydrogen gas and 1,3-propanediol (PD), was examined using anaerobic fermentation with heat-treated mixed cultures. Glycerol fermentation produced 0.28 mol-H 2/mol-glycerol (72 mL-H2/g

  5. The Roles of Biofilm Conductivity and Donor Substrate Kinetics in a Mixed-Culture Biofilm Anod

    Science.gov (United States)

    We experimentally assessed kinetics and thermodynamics of electron transfer (ET) from the donor substrate (acetate) to the anode for a mixed-culture biofilm anode. We interpreted the results with a modified biofilm-conduction model consisting of three ET steps: (1) intracellular...

  6. Bioelectrochemical production of caproate and caprylate from acetate by mixed cultures

    NARCIS (Netherlands)

    Eerten-Jansen, van M.C.A.A.; Heijne, ter A.; Grootscholten, T.I.M.; Steinbusch, K.J.J.; Sleutels, T.H.J.A.; Hamelers, H.V.M.; Buisman, C.J.N.

    2013-01-01

    The use of mixed cultures to convert waste biomass into medium chain fatty acids, precursors for renewable fuels or chemicals, is a promising route. To convert waste biomass into medium chain fatty acids, an external electron donor in the form of hydrogen or ethanol needs to be added. This study

  7. Development of a mixed culture chain elongation process based on municipal solid waste and ethanol

    NARCIS (Netherlands)

    Grootscholten, T.I.M.

    2013-01-01

    Keywords: mixed culture fermentation; Carboxylates; Caproate; Heptanoate; ethanol; OFMSW

    To reduce dependence on oil, alternative fuel and chemical production processes are investigates. In this thesis, we investigated the production of medium chain fatty acids (MCFAs) using an anaerobic

  8. Determination of D10 values of single and mixed cultures of bacteria after gamma irradiation

    International Nuclear Information System (INIS)

    Adu-Gyamfi, A.; Nketsia-Tabiri, J.; Boatin, R.

    2009-01-01

    The D 10 value of bacteria represents the absorbed radiation dose required to inactivate 90 % of a viable population or reduce the population by a factor of 10. D 10 values of 3 bacterial isolates (Escherichia coli, Staphylococcus aureus and Salmonella parathyphi B) were determined using single and mixed cultures to assess the effect of microbial competition on radiosensitivity. The isolates were inoculated into wakye substrate and exposed to γ-radiation doses of 0, 100, 300, 450, 600, 750, 850 Gy from a 6O Co source at a dose rate of 2.20 kGy/h in air. Enumeration of survivors of the isolates was carried out using serial dilution and pour plate methods. The surviving fraction of isolates decreased with increased irradiation doses. D 10 values of E. coli, S. aureus and S. parathyphi B were respectively 0.27, 0.33 and 0.44 kGy when inoculated as single cultures, and 0.24, 0.28 and 0.32 kGy respectively when inoculated as mixed cultures. D 10 values were lower for mixed cultures compared to single cultures, which might indicate reduced resistance to γ-radiation as a result of competition among the isolates. Microbiological challenge tests based on the D 10 values may result in delivery of higher irradiation doses, but the extra dose could serve as safety margin to enhance the food preservative capacity of radiation processing. (au)

  9. Substrate interactions of benzene, toluene, and para-xylene during microbial degradation by pure cultures and mixed culture aquifer slurries

    International Nuclear Information System (INIS)

    Alvarez, P.J.J.; Vogel, T.M.

    1991-01-01

    Release of petroleum hydrocarbons in the environment is a widespread occurrence. One particular concern is the contamination of drinking water sources by the toxic, water-soluble, and mobile petroleum components benzene, toluene, and xylene (BTX). Benzene, toluene, and p-xylene (BTX) were degraded by indigenous mixed cultures in sandy aquifer material and by two pure cultures isolated from the same site. Although BTX compounds have a similar chemical structure, the fate of individual BTX compounds differed when the compounds were fed to each pure culture and mixed culture aquifer slurries. The identification of substrate interactions aided the understanding of this behavior. Beneficial substrate interactions included enhanced degradation of benzene-dependent degradation of toluene and p-xylene by Arthrobacter sp. strain HCB. Detrimental substrate interactions included retardation in benzene and toluene degradation by the presence of p-xylene in both aquifer slurries and Pseudomonas incubations. The catabolic diversity of microbes in the environment precludes generalizations about the capacity of individual BTX compounds to enhance or inhibit the degradation of other BTX compounds

  10. Kynurenic Acid Prevents Cytoskeletal Disorganization Induced by Quinolinic Acid in Mixed Cultures of Rat Striatum.

    Science.gov (United States)

    Pierozan, Paula; Biasibetti-Brendler, Helena; Schmitz, Felipe; Ferreira, Fernanda; Pessoa-Pureur, Regina; Wyse, Angela T S

    2018-06-01

    Kynurenic acid (KYNA) is a neuroactive metabolite of tryptophan known to modulate a number of mechanisms involved in neural dysfunction. Although its activity in the brain has been widely studied, the effect of KYNA counteracting the actions of quinolinic acid (QUIN) remains unknown. The present study aims at describing the ability of 100 μM KYNA preventing cytoskeletal disruption provoked by QUIN in astrocyte/neuron/microglia mixed culture. KYNA totally preserved cytoskeletal organization, cell morphology, and redox imbalance in mixed cultures exposed to QUIN. However, KYNA partially prevented morphological alteration in isolated primary astrocytes and failed to protect the morphological alterations of neurons caused by QUIN exposure. Moreover, KYNA prevented QUIN-induced microglial activation and upregulation of ionized calcium-binding adapter molecule 1 (Iba-1) and partially preserved tumor necrosis factor-α (TNF-α) level in mixed cultures. TNF-α level was also partially preserved in astrocytes. In addition to the mechanisms dependent on redox imbalance and microglial activation, KYNA prevented downregulation of connexin-43 and the loss of functionality of gap junctions (GJs), preserving cell-cell contact, cytoskeletal organization, and cell morphology in QUIN-treated cells. Furthermore, the toxicity of QUIN targeting the cytoskeleton of mixed cultures was not prevented by the N-methyl-D-aspartate (NMDA) antagonist MK-801. We suggest that KYNA protects the integrity of the cytoskeleton of mixed cultures by complex mechanisms including modulating microglial activation preventing oxidative imbalance and misregulated GJs leading to disrupted cytoskeleton in QUIN-treated cells. This study contributed to elucidate the molecular basis of KYNA protection against QUIN toxicity.

  11. Ultrastructural changes in biofilm forms of staphylococci cultivated in a mixed culture with lactobacilli

    Directory of Open Access Journals (Sweden)

    G. Lavryk

    2017-02-01

    Full Text Available The capacity of opportunistic bacteria for biofilm formation plays an important role in the development of chronic inflammatory processes, which are difficult to treat. To improve antimicrobial therapy methods, the influence of lactobacilli on the ultrastructure of biofilm-forming clinical strains of staphylococci when co-cultured was investigated. 5 biofilm-forming clinical strains of S. aureus from the skin of acne vulgaris patients (n = 24 were isolated. Using transmission electron microscopy (TEM the morphological changes of S. aureus cells in the mixed culture with standard strains of Lactobacillus plantarum 8P-A3 and clinical strains of L. fermentum (n = 4 were studied. It was found that in 48 hours after the inoculation on the medium of samples of mixed cultures of L. plantarum 8P-A3 and S. aureus growth of staphylococci was not revealed. Only in some cases of mixed cultures of L. fermentum and biofilm-forming staphylococci was growth of S. aureus obtained. In electron diffraction patterns of control samples of 24-hour staphylococcal monocultures and 48-hour lactobacilli monocultures, natural development of the population at the cellular level was observed. Destructive changes under the influence of lactobacilli (probiotic and clinical strains were detected in all ultrathin sections of the cells of biofilm-forming and planktonic staphylococci. Significant destructive changes in the cell wall of the staphylococci were observed: thickening, obtaining of irregular form, detachment of the cytoplasmic membrane, the complete destruction of the peptidoglycan layer and the emergence of "shadow cells". On all electron diffraction patterns fibrillar-threadlike structures of DNA could not be observed, but in some cases mesosome-like formations were poorly contrasted. It was established that the surface S-layer of lactobacilli was expressed on a significantly larger scale in the mixed culture with staphylococci. In mixed culture of clinical strains

  12. Relevance of workplace social mixing during influenza pandemics: an experimental modelling study of workplace cultures.

    Science.gov (United States)

    Timpka, T; Eriksson, H; Holm, E; Strömgren, M; Ekberg, J; Spreco, A; Dahlström, Ö

    2016-07-01

    Workplaces are one of the most important regular meeting places in society. The aim of this study was to use simulation experiments to examine the impact of different workplace cultures on influenza dissemination during pandemics. The impact is investigated by experiments with defined social-mixing patterns at workplaces using semi-virtual models based on authentic sociodemographic and geographical data from a North European community (population 136 000). A simulated pandemic outbreak was found to affect 33% of the total population in the community with the reference academic-creative workplace culture; virus transmission at the workplace accounted for 10·6% of the cases. A model with a prevailing industrial-administrative workplace culture generated 11% lower incidence than the reference model, while the model with a self-employed workplace culture (also corresponding to a hypothetical scenario with all workplaces closed) produced 20% fewer cases. The model representing an academic-creative workplace culture with restricted workplace interaction generated 12% lower cumulative incidence compared to the reference model. The results display important theoretical associations between workplace social-mixing cultures and community-level incidence rates during influenza pandemics. Social interaction patterns at workplaces should be taken into consideration when analysing virus transmission patterns during influenza pandemics.

  13. Microbial Fuel Cells using Mixed Cultures of Wastewater for Electricity Generation

    International Nuclear Information System (INIS)

    Zain, S.M; Roslani, N.S.; Hashim, R.; Anuar, N.; Suja, F.; Basi, N.E.A.; Anuar, N.; Daud, W.R.W.

    2011-01-01

    Fossil fuels (petroleum, natural gas and coal) are the main resources for generating electricity. However, they have been major contributors to environmental problems. One potential alternative to explore is the use of microbial fuel cells (MFCs), which generate electricity using microorganisms. MFCs uses catalytic reactions activated by microorganisms to convert energy preserved in the chemical bonds between organic molecules into electrical energy. MFC has the ability to generate electricity during the wastewater treatment process while simultaneously treating the pollutants. This study investigated the potential of using different types of mixed cultures (raw sewage, mixed liquor from the aeration tank and return waste activated sludge) from an activated sludge treatment plant in MFCs for electricity generation and pollutant removals (COD and total kjeldahl nitrogen, TKN). The MFC in this study was designed as a dual-chambered system, in which the chambers were separated by a Nafion TM membrane using a mixed culture of wastewater as a bio catalyst. The maximum power density generated using activated sludge was 9.053 mW/ cm 2 , with 26.8 % COD removal and 40 % TKN removal. It is demonstrated that MFC offers great potential to optimize power generation using mixed cultures of wastewater. (author)

  14. Mixed Cultures Fermentation for the Production of Poly-ß-hydroxybutyrate

    Directory of Open Access Journals (Sweden)

    Thomas Shalin

    2014-10-01

    Full Text Available Poly-ß-hydroxybutyrate (PHB is a biodegradable intracellular microbial product produced by many bacteria and it is comparable to some of the petrochemical derived thermoplastics such as polypropylene. One of the main barriers for the commercial exploitation is the high cost of the substrate for the production of biopolymer. The utilization of mixed microbial cultures facilitates the use of complex substrates thereby reducing the cost of PHB production. In the present study, mixed culture systems were evaluated for PHB production. Bacillus firmus NII 0830 was used for the production of PHB since it accumulates a large amount of PHB and a second organism Lactobacillus delbrueckii NII 0925 was used to provide lactic acid. FTIR and 1H NMR analyses revealed that the PHB extracted from pure culture and mixed culture showed exact match to that of standard PHB. Biodegradation studies of the PHB blends showed 87% degradation. It was also found that a consortium of organisms degraded the films faster than a single organism.

  15. Cultural continuity, traditional Indigenous language, and diabetes in Alberta First Nations: a mixed methods study.

    Science.gov (United States)

    Oster, Richard T; Grier, Angela; Lightning, Rick; Mayan, Maria J; Toth, Ellen L

    2014-10-19

    We used an exploratory sequential mixed methods approach to study the association between cultural continuity, self-determination, and diabetes prevalence in First Nations in Alberta, Canada. We conducted a qualitative description where we interviewed 10 Cree and Blackfoot leaders (members of Chief and Council) from across the province to understand cultural continuity, self-determination, and their relationship to health and diabetes, in the Alberta First Nations context. Based on the qualitative findings, we then conducted a cross-sectional analysis using provincial administrative data and publically available data for 31 First Nations communities to quantitatively examine any relationship between cultural continuity and diabetes prevalence. Cultural continuity, or "being who we are", is foundational to health in successful First Nations. Self-determination, or "being a self-sufficient Nation", stems from cultural continuity and is seriously compromised in today's Alberta Cree and Blackfoot Nations. Unfortunately, First Nations are in a continuous struggle with government policy. The intergenerational effects of colonization continue to impact the culture, which undermines the sense of self-determination, and contributes to diabetes and ill health. Crude diabetes prevalence varied dramatically among First Nations with values as low as 1.2% and as high as 18.3%. Those First Nations that appeared to have more cultural continuity (measured by traditional Indigenous language knowledge) had significantly lower diabetes prevalence after adjustment for socio-economic factors (p =0.007). First Nations that have been better able to preserve their culture may be relatively protected from diabetes.

  16. Quantitation of DNA repair in brain cell cultures: implications for autoradiographic analysis of mixed cell populations

    International Nuclear Information System (INIS)

    Dambergs, R.; Kidson, C.

    1979-01-01

    Quantitation of DNA repair in the mixed cell population of mouse embryo brain cultures has been assessed by autoradiographic analysis of unscheduled DNA synthesis following UV-irradiation. The proportion of labelled neurons and the grain density over neuronal nuclei were both less than the corresponding values for glial cells. The nuclear geometries of these two classes of cell are very different. Partial correction for the different geometries by relating grain density to nuclear area brought estimates of neuronal and glial DNA repair synthesis more closely in line. These findings have general implications for autoradiographic measurement of DNA repair in mixed cell populations and in differentiated versus dividing cells. (author)

  17. [Methanotrophs of the psychrophilic microbial community of the Russian Arctic tundra].

    Science.gov (United States)

    Berestovskaia, Iu Iu; Vasil'eva, L V; Chestnykh, O V; Zavarzin, G A

    2002-01-01

    In tundra, at a low temperature, there exists a slowly developing methanotrophic community. Methane-oxidizing bacteria are associated with plants growing at high humidity, such as sedge and sphagnum; no methonotrophs were found in polytrichous and aulacomnious mosses and lichens, typical of more arid areas. The methanotrophic bacterial community inhabits definite soil horizons, from moss dust to peat formed from it. Potential ability of the methanotrophic community to oxidize methane at 5 degrees C enhances with the depth of the soil profile in spite of the decreasing soil temperature. The methanotrophic community was found to gradually adapt to various temperatures due to the presence of different methane-oxidizing bacteria in its composition. Depending on the temperature and pH, different methanotrophs occupy different econiches. Within a temperature range from 5 to 15 degrees C, three morphologically distinct groups of methanotrophs could be distinguished. At pH 5-7 and 5-15 degrees C, forms morphologically similar to Methylobacter psychrophilus predominated, whereas at the acidic pH 4-6 and 10-15 degrees C, bipolar cells typical of Methylocella palustris were mostly found. The third group of methanotrophic bacteria growing at pH 5-7 and 5-10 degrees C was represented by a novel methanotroph whole large coccoid cells had a thick mucous capsule.

  18. A Moderately Thermophilic Mixed Microbial Culture for Bioleaching of Chalcopyrite Concentrate at High Pulp Density

    Science.gov (United States)

    Wang, Yuguang; Zeng, Weimin; Qiu, Guanzhou; Chen, Xinhua

    2014-01-01

    Three kinds of samples (acid mine drainage, coal mine wastewater, and thermal spring) derived from different sites were collected in China. Thereafter, these samples were combined and then inoculated into a basal salts solution in which different substrates (ferrous sulfate, elemental sulfur, and chalcopyrite) served as energy sources. After that, the mixed cultures growing on different substrates were pooled equally, resulting in a final mixed culture. After being adapted to gradually increasing pulp densities of chalcopyrite concentrate by serial subculturing for more than 2 years, the final culture was able to efficiently leach the chalcopyrite at a pulp density of 20% (wt/vol). At that pulp density, the culture extracted 60.4% of copper from the chalcopyrite in 25 days. The bacterial and archaeal diversities during adaptation were analyzed by denaturing gradient gel electrophoresis and constructing clone libraries of the 16S rRNA gene. The results show that the culture consisted mainly of four species, including Leptospirillum ferriphilum, Acidithiobacillus caldus, Sulfobacillus acidophilus, and Ferroplasma thermophilum, before adapting to a pulp density of 4%. However, L. ferriphilum could not be detected when the pulp density was greater than 4%. Real-time quantitative PCR was employed to monitor the microbial dynamics during bioleaching at a pulp density of 20%. The results show that A. caldus was the predominant species in the initial stage, while S. acidophilus rather than A. caldus became the predominant species in the middle stage. F. thermophilum accounted for the greatest proportion in the final stage. PMID:24242252

  19. Comparative analysis of microbial community of novel lactic acid fermentation inoculated with different undefined mixed cultures.

    Science.gov (United States)

    Liang, Shaobo; Gliniewicz, Karol; Mendes-Soares, Helena; Settles, Matthew L; Forney, Larry J; Coats, Erik R; McDonald, Armando G

    2015-03-01

    Three undefined mixed cultures (activated sludge) from different municipal wastewater treatment plants were used as seeds in a novel lactic acid fermentation process fed with potato peel waste (PPW). Anaerobic sequencing batch fermenters were run under identical conditions to produce predominantly lactic acid. Illumina sequencing was used to examine the 16S rRNA genes of bacteria in the three seeds and fermenters. Results showed that the structure of microbial communities of three seeds were different. All three fermentation products had unique community structures that were dominated (>96%) by species of the genus Lactobacillus, while members of this genus constituted undefined mixed cultures were robust and resilient, which provided engineering prospects for the microbial utilization of carbohydrate wastes to produce lactic acid. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Bioremediation of Phenanthrene by Monocultures and Mixed Culture Bacteria Isolated from Contaminated Soil

    OpenAIRE

    A. Fazilah; I. Darah; I. Noraznawati

    2016-01-01

    Three different bacteria capable of degrading phenanthrene were isolated from hydrocarbon contaminated site. In this study, the phenanthrene-degrading activity by defined monoculture was determined and mixed culture was identified as Acinetobacter sp. P3d, Bacillus sp. P4a and Pseudomonas sp. P6. All bacteria were able to grow in a minimal salt medium saturated with phenanthrene as the sole source of carbon and energy. Phenanthrene degradation efficiencies by different combinations (consortia...

  1. Influence of chemical surfactants on the biodegradation of crude oil by a mixed bacterial culture

    International Nuclear Information System (INIS)

    Van Hamme, J.D.; Ward, O.P.

    1999-01-01

    A study was conducted in which the effects of surfactant physicochemical properties on crude oil biodegradation by a mixed-bacterial culture were examined. The effects of hydrophile-lipophile balance (HLB) and molecular structure on the biodegradation of Bow River crude oil were determined. It was shown that chemical surfactants have the potential to improve crude oil biodegradation in complex microbial systems. Surfactant selection should consider factors such as molecular structure, HLB and surfactant concentration. 26 refs., 4 tabs., 3 figs

  2. Detection of autotrophic verrucomicrobial methanotrophs in a geothermal environment using stable isotope probing

    Directory of Open Access Journals (Sweden)

    Christine eSharp

    2012-08-01

    Full Text Available Genomic analysis of the methanotrophic verrucomicrobium Methylacidiphilum infernorum strain V4 has shown that most pathways conferring its methanotrophic lifestyle are similar to those found in proteobacterial methanotrophs. However, due to the large sequence divergence of its methane monooxygenase-encoding genes (pmo, ‘universal’ pmoA polymerase chain reaction (PCR primers do not target these bacteria. Unlike proteobacterial methanotrophs, Methylacidiphilum fixes carbon autotrophically, and uses methane only for energy generation. As a result, techniques used to detect methanotrophs in the environment such as 13CH4-stable isotope probing (SIP and pmoA-targeted PCR do not detect verrucomicrobial methanotrophs, and they may have been overlooked in previous environmental studies. We developed a modified SIP technique to identify active methanotrophic verrucomicrobia in the environment by labelling with 13CO2 and 13CH4, individually and in combination. Testing the protocol in M. infernorum strain V4 resulted in assimilation of 13CO2 but not 13CH4, verifying its autotrophic lifestyle. To specifically detect methanotrophs (as opposed to other autotrophs via 13CO2-SIP, a quantitative PCR (qPCR assay specific for verrucomicrobial-pmoA genes was developed and used in combination with SIP. Incubation of an acidic, high-temperature geothermal soil with 13CH4 + 12CO2 caused little shift in the density distribution of verrucomicrobial-pmoA genes relative to controls. However, labelling with 13CO2 in combination with 12CH4 or 13CH4 induced a strong shift in the distribution of verrucomicrobial-pmoA genes towards the heavy DNA fractions. The modified SIP technique demonstrated that the primary methanotrophs active in the soil were autotrophs and belonged to the Verrucomicrobia. This is the first demonstration of autotrophic, non-proteobacterial methanotrophy in situ, and provides a tool to detect verrucomicrobial methanotrophs in other ecosystems.

  3. Detection of autotrophic verrucomicrobial methanotrophs in a geothermal environment using stable isotope probing.

    Science.gov (United States)

    Sharp, Christine E; Stott, Matthew B; Dunfield, Peter F

    2012-01-01

    Genomic analysis of the methanotrophic verrucomicrobium "Methylacidiphilum infernorum" strain V4 has shown that most pathways conferring its methanotrophic lifestyle are similar to those found in proteobacterial methanotrophs. However, due to the large sequence divergence of its methane monooxygenase-encoding genes (pmo), "universal" pmoA polymerase chain reaction (PCR) primers do not target these bacteria. Unlike proteobacterial methanotrophs, "Methylacidiphilum" fixes carbon autotrophically, and uses methane only for energy generation. As a result, techniques used to detect methanotrophs in the environment such as (13)CH(4)-stable isotope probing (SIP) and pmoA-targeted PCR do not detect verrucomicrobial methanotrophs, and they may have been overlooked in previous environmental studies. We developed a modified SIP technique to identify active methanotrophic Verrucomicrobia in the environment by labeling with (13)CO(2) and (13)CH(4), individually and in combination. Testing the protocol in "M. infernorum" strain V4 resulted in assimilation of (13)CO(2) but not (13)CH(4), verifying its autotrophic lifestyle. To specifically detect methanotrophs (as opposed to other autotrophs) via (13)CO(2)-SIP, a quantitative PCR (qPCR) assay specific for verrucomicrobial-pmoA genes was developed and used in combination with SIP. Incubation of an acidic, high-temperature geothermal soil with (13)CH(4) + (12)CO(2) caused little shift in the density distribution of verrucomicrobial-pmoA genes relative to controls. However, labeling with (13)CO(2) in combination with (12)CH(4) or (13)CH(4) induced a strong shift in the distribution of verrucomicrobial-pmoA genes towards the heavy DNA fractions. The modified SIP technique demonstrated that the primary methanotrophs active in the soil were autotrophs and belonged to the Verrucomicrobia. This is the first demonstration of autotrophic, non-proteobacterial methanotrophy in situ, and provides a tool to detect verrucomicrobial methanotrophs

  4. Community Structure of Active Aerobic Methanotrophs in Red Mangrove (Kandelia obovata) Soils Under Different Frequency of Tides.

    Science.gov (United States)

    Shiau, Yo-Jin; Cai, Yuanfeng; Lin, Yu-Te; Jia, Zhongjun; Chiu, Chih-Yu

    2018-04-01

    Methanotrophs are important microbial communities in coastal ecosystems. They reduce CH 4 emission in situ, which is influenced by soil conditions. This study aimed to understand the differences in active aerobic methanotrophic communities in mangrove forest soils experiencing different inundation frequency, i.e., in soils from tidal mangroves, distributed at lower elevations, and from dwarf mangroves, distributed at higher elevations. Labeling of pmoA gene of active methanotrophs using DNA-based stable isotope probing (DNA-SIP) revealed that methanotrophic activity was higher in the dwarf mangrove soils than in the tidal mangrove soils, possibly because of the more aerobic soil conditions. Methanotrophs affiliated with the cluster deep-sea-5 belonging to type Ib methanotrophs were the most dominant methanotrophs in the fresh mangrove soils, whereas type II methanotrophs also appeared in the fresh dwarf mangrove soils. Furthermore, Methylobacter and Methylosarcina were the most important active methanotrophs in the dwarf mangrove soils, whereas Methylomonas and Methylosarcina were more active in the tidal mangrove soils. High-throughput sequencing of the 16S ribosomal RNA (rRNA) gene also confirmed similar differences in methanotrophic communities at the different locations. However, several unclassified methanotrophic bacteria were found by 16S rRNA MiSeq sequencing in both fresh and incubated mangrove soils, implying that methanotrophic communities in mangrove forests may significantly differ from the methanotrophic communities documented in previous studies. Overall, this study showed the feasibility of 13 CH 4 DNA-SIP to study the active methanotrophic communities in mangrove forest soils and revealed differences in the methanotrophic community structure between coastal mangrove forests experiencing different tide frequencies.

  5. Immunoglobulin production in human mixed lymphocyte cultures: implications for co-cultures of cells from patients and healthy donors

    International Nuclear Information System (INIS)

    Ruemke, H.C.; Terpstra, F.G.; Huis, B.; Out, T.A.; Zeijlemaker, W.P.

    1982-01-01

    When human peripheral blood lymphocytes (PBL) are cultured in the presence of irradiated allogeneic lymphocytes, the resulting mixed lymphocyte reaction (MLR) leads to the secretion into the supernatant of substantial amounts of IgM and IgG, derived from nonirradiated responder B lymphocytes. Our data indicate that stimulation to Ig production by responder B cells may result from different types of of interactions. First, B cells and monocytes among the irradiated stimulator cells activate T responder B cells to produce Ig; second, ''responder'' B cells activate irradiated ''stimulator'' T cells, leading to a ''helper'' signal, back to the responder B cells and leading to Ig production. The latter system is radiosensitive, because allogeneic T cells, irradiated at a dose of 4000 rad or more, failed to induce Ig production by responder B cells. In some combinations of human allogeneic lymphocytes, the co-culture of the cells leads to inhibition of Ig production, both in the presence and in the absence of PWM. Thus, co-culture of allogeneic cells may cause ''positive'' as well as ''negative'' allogeneic effects. The implications of these findings for the interpretation of co-cultures that are aimed at establishing defects in lymphocytes from patients with, for example, immunodeficiencies, who fail to produce Ig in the presence of PWM are discussed

  6. Temperature dependence of bioelectrochemical CO2 conversion and methane production with a mixed-culture biocathode.

    Science.gov (United States)

    Yang, Hou-Yun; Bao, Bai-Ling; Liu, Jing; Qin, Yuan; Wang, Yi-Ran; Su, Kui-Zu; Han, Jun-Cheng; Mu, Yang

    2018-02-01

    This study evaluated the effect of temperature on methane production by CO 2 reduction during microbial electrosynthesis (MES) with a mixed-culture biocathode. Reactor performance, in terms of the amount and rate of methane production, current density, and coulombic efficiency, was compared at different temperatures. The microbial properties of the biocathode at each temperature were also analyzed by 16S rRNA gene sequencing. The results showed that the optimum temperature for methane production from CO 2 reduction in MES with a mixed-culture cathode was 50°C, with the highest amount and rate of methane production of 2.06±0.13mmol and 0.094±0.01mmolh -1 , respectively. In the mixed-culture biocathode MES, the coulombic efficiency of methane formation was within a range of 19.15±2.31% to 73.94±2.18% due to by-product formation at the cathode, including volatile fatty acids and hydrogen. Microbial analysis demonstrated that temperature had an impact on the diversity of microbial communities in the biofilm that formed on the MES cathode. Specifically, the hydrogenotrophic methanogen Methanobacterium became the predominant archaea for methane production from CO 2 reduction, while the abundance of the aceticlastic methanogen Methanosaeta decreased with increased temperature. Copyright © 2017. Published by Elsevier B.V.

  7. Enhanced hydrogen and 1,3-propanediol production from glycerol by fermentation using mixed cultures

    KAUST Repository

    Selembo, Priscilla A.

    2009-12-15

    The conversion of glycerol into high value products, such as hydrogen gas and 1,3-propanediol (PD), was examined using anaerobic fermentation with heat-treated mixed cultures. Glycerol fermentation produced 0.28 mol-H 2/mol-glycerol (72 mL-H2/g-COD) and 0.69 mol-PD/mol-glycerol. Glucose fermentation using the same mixed cultures produced more hydrogen gas (1.06 mol-H2/mol-glucose) but no PD. Changing the source of inoculum affected gas production likely due to prior acclimation of bacteria to this type of substrate. Fermentation of the glycerol produced from biodiesel fuel production (70% glycerol content) produced 0.31 mol-H 2/mol-glycerol (43 mL H2/g-COD) and 0.59 mol-PD/mol-glycerol. These are the highest yields yet reported for both hydrogen and 1,3-propanediol production from pure glycerol and the glycerol byproduct from biodiesel fuel production by fermentation using mixed cultures. These results demonstrate that production of biodiesel can be combined with production of hydrogen and 1,3-propanediol for maximum utilization of resources and minimization of waste. © 2009 Wiley Periodicals, Inc.

  8. Enzymatic activities produced by mixed Saccharomyces and non-Saccharomyces cultures: relationship with wine volatile composition.

    Science.gov (United States)

    Maturano, Yolanda Paola; Assof, Mariela; Fabani, María Paula; Nally, María Cristina; Jofré, Viviana; Rodríguez Assaf, Leticia Anahí; Toro, María Eugenia; Castellanos de Figueroa, Lucía Inés; Vazquez, Fabio

    2015-11-01

    During certain wine fermentation processes, yeasts, and mainly non-Saccharomyces strains, produce and secrete enzymes such as β-glucosidases, proteases, pectinases, xylanases and amylases. The effects of enzyme activity on the aromatic quality of wines during grape juice fermentation, using different co-inoculation strategies of non-Saccharomyces and Saccharomyces cerevisiae yeasts, were assessed in the current study. Three strains with appropriate enological performance and high enzymatic activities, BSc562 (S. cerevisiae), BDv566 (Debaryomyces vanrijiae) and BCs403 (Candida sake), were assayed in pure and mixed Saccharomyces/non-Saccharomyces cultures. β-Glucosidase, pectinase, protease, xylanase and amylase activities were quantified during fermentations. The aromatic profile of pure and mixed cultures was determined at the end of each fermentation. In mixed cultures, non-Saccharomyces species were detected until day 4-5 of the fermentation process, and highest populations were observed in MSD2 (10% S. cerevisiae/90% D. vanrijiae) and MSC1 (1% S. cerevisiae/99% C. sake). According to correlation and multivariate analysis, MSD2 presented the highest concentrations of terpenes and higher alcohols which were associated with pectinase, amylase and xylanase activities. On the other hand, MSC1 high levels of β-glucosidase, proteolytic and xylanolytic activities were correlated to esters and fatty acids. Our study contributes to a better understanding of the effect of enzymatic activities by yeasts on compound transformations that occur during wine fermentation.

  9. Behavioral profile of Macrobrachium rosenbergii in mixed and monosex culture submitted to shelters of different colors

    Directory of Open Access Journals (Sweden)

    Daniele Bezerra Santos

    2015-07-01

    Full Text Available Current research analyzed the behavioral activities of Macrobrachium rosenbergii and its preference for colored shelters in male monosex, female monosex and mixed culture. Ten shrimps m-2 were maintained in eight 250-L aquaria. Three artificial shelters, colored red, black and orange, were placed in each aquarium. Four aquaria were maintained in light/dark photoperiod respectively between 6h00 am and 6h00 pm and between 6h00 pm and 6h00 am, whereas the other four aquaria were submitted to an inverted photoperiod. The animals were observed for 30 days by Focal Animal Method for 15 minutes, with instantaneous recording every 60 seconds, at six different instances within the light and dark phases. Preference for black shelters occurred in male monosex and mixed cultures, whereas red and orange shelters were the preference of female monosex. M. rosenbergii kept in the shelter mostly during the light phase in male monosex and mixed populations. Results suggest that black, red and orange shelters may improve the animals' well-being in the culture since aggressive encounters would decrease, especially during the light phase.

  10. Highly Sensitive Bacteriophage-Based Detection of Brucella abortus in Mixed Culture and Spiked Blood

    Directory of Open Access Journals (Sweden)

    Kirill V. Sergueev

    2017-06-01

    Full Text Available For decades, bacteriophages (phages have been used for Brucella species identification in the diagnosis and epidemiology of brucellosis. Traditional Brucella phage typing is a multi-day procedure including the isolation of a pure culture, a step that can take up to three weeks. In this study, we focused on the use of brucellaphages for sensitive detection of the pathogen in clinical and other complex samples, and developed an indirect method of Brucella detection using real-time quantitative PCR monitoring of brucellaphage DNA amplification via replication on live Brucella cells. This assay allowed the detection of single bacteria (down to 1 colony-forming unit per milliliter within 72 h without DNA extraction and purification steps. The technique was equally efficient with Brucella abortus pure culture and with mixed cultures of B. abortus and α-proteobacterial near neighbors that can be misidentified as Brucella spp., Ochrobactrum anthropi and Afipia felis. The addition of a simple short sample preparation step enabled the indirect phage-based detection of B. abortus in spiked blood, with the same high sensitivity. This indirect phage-based detection assay enables the rapid and sensitive detection of live B. abortus in mixed cultures and in blood samples, and can potentially be applied for detection in other clinical samples and other complex sample types.

  11. Highly Sensitive Bacteriophage-Based Detection of Brucella abortus in Mixed Culture and Spiked Blood.

    Science.gov (United States)

    Sergueev, Kirill V; Filippov, Andrey A; Nikolich, Mikeljon P

    2017-06-10

    For decades, bacteriophages (phages) have been used for Brucella species identification in the diagnosis and epidemiology of brucellosis. Traditional Brucella phage typing is a multi-day procedure including the isolation of a pure culture, a step that can take up to three weeks. In this study, we focused on the use of brucellaphages for sensitive detection of the pathogen in clinical and other complex samples, and developed an indirect method of Brucella detection using real-time quantitative PCR monitoring of brucellaphage DNA amplification via replication on live Brucella cells. This assay allowed the detection of single bacteria (down to 1 colony-forming unit per milliliter) within 72 h without DNA extraction and purification steps. The technique was equally efficient with Brucella abortus pure culture and with mixed cultures of B . abortus and α-proteobacterial near neighbors that can be misidentified as Brucella spp., Ochrobactrum anthropi and Afipia felis . The addition of a simple short sample preparation step enabled the indirect phage-based detection of B . abortus in spiked blood, with the same high sensitivity. This indirect phage-based detection assay enables the rapid and sensitive detection of live B . abortus in mixed cultures and in blood samples, and can potentially be applied for detection in other clinical samples and other complex sample types.

  12. Highly Sensitive Bacteriophage-Based Detection of Brucella abortus in Mixed Culture and Spiked Blood

    Science.gov (United States)

    Sergueev, Kirill V.; Filippov, Andrey A.; Nikolich, Mikeljon P.

    2017-01-01

    For decades, bacteriophages (phages) have been used for Brucella species identification in the diagnosis and epidemiology of brucellosis. Traditional Brucella phage typing is a multi-day procedure including the isolation of a pure culture, a step that can take up to three weeks. In this study, we focused on the use of brucellaphages for sensitive detection of the pathogen in clinical and other complex samples, and developed an indirect method of Brucella detection using real-time quantitative PCR monitoring of brucellaphage DNA amplification via replication on live Brucella cells. This assay allowed the detection of single bacteria (down to 1 colony-forming unit per milliliter) within 72 h without DNA extraction and purification steps. The technique was equally efficient with Brucella abortus pure culture and with mixed cultures of B. abortus and α-proteobacterial near neighbors that can be misidentified as Brucella spp., Ochrobactrum anthropi and Afipia felis. The addition of a simple short sample preparation step enabled the indirect phage-based detection of B. abortus in spiked blood, with the same high sensitivity. This indirect phage-based detection assay enables the rapid and sensitive detection of live B. abortus in mixed cultures and in blood samples, and can potentially be applied for detection in other clinical samples and other complex sample types. PMID:28604602

  13. Proteolytically modified human beta 2-microglobulin augments the specific cytotoxic activity in murine mixed lymphocyte culture

    DEFF Research Database (Denmark)

    Nissen, Mogens Holst; Claësson, M H

    1987-01-01

    the endogenous production of interleukin 2 in the MLC culture; monoclonal antibody which reacts with both the native beta 2-m and M-beta 2-m molecule blocks the augmentation of cytotoxic T lymphocyte production induced by M-beta 2-m; murine as well as human MLC responder cells can proteolytically modify native......A proteolytically modified form of beta 2-microglobulin (beta 2-m) present in the serum of patients suffering from autoimmune, immunodeficient diseases and cancer has been reported in the literature. In the present study we show that human beta 2-m as well as the proteolytically modified human form...... (M-beta 2-m) bind to murine lymphocytes expressing H-2 class I antigens; M-beta 2-m, when added at day 0 and 1 of culture in nanomolar concentrations to a one-way murine allogeneic mixed lymphocyte culture (MLC) augments the generation of specific cytotoxic T lymphocytes; M-beta 2-m increases...

  14. A safety culture assessment by mixed methods at a public maternity and infant hospital in China

    Directory of Open Access Journals (Sweden)

    Listyowardojo TA

    2017-07-01

    Full Text Available Tita Alissa Listyowardojo,1 Xiaoling Yan,2,3 Stephen Leyshon,1 Bobbie Ray-Sannerud,1 Xin Yan Yu,4 Kai Zheng,4 Tao Duan2,3 1Life Sciences Program, Group Technology and Research, DNV GL, Hovik, Norway; 2Quality and Safety Department, Shanghai First Maternity and Infant Hospital, 3Tongji University School of Medicine, Shanghai, 4Healthcare Department, Business Assurance, DNV GL, Beijing, China Objective: To assess safety culture at a public maternity hospital in Shanghai, China, using a sequential mixed methods approach. The study was part of a bigger study looking at the application of the mixed methods approach to assess safety culture in health care in different organizations and countries.Methodology: A mixed methods approach was utilized by first distributing the Safety Attitudes Questionnaire measuring six safety culture dimensions and five independent items to all hospital staff (n=1482 working in 18 departments at a single hospital. Afterward, semistructured interviews were conducted using convenience sampling, where 48 hospital staff from nine departments at the same hospital were individually interviewed.Results: The survey received a response rate of 96%. The survey findings show significant differences between the hospital departments in almost all safety culture dimensions and independent items. Similarly, the interview findings revealed that there were different, competing priorities between departments perceived to result in a reduced quality of collaboration and bottlenecks in care delivery. Another major finding was that staff who worked more hours per week would perceive working conditions significantly more negatively. Issues related to working conditions were also the most common concerns discussed in the interviews, especially the issue on high workload. High workload was also reflected in the fact that 91.45% of survey respondents reported that they worked 40 hours or longer per week. Finally, interview findings complemented

  15. Improved ethanol tolerance of Saccharomyces cerevisiae in mixed cultures with Kluyveromyces lactis on high-sugar fermentation.

    Science.gov (United States)

    Yamaoka, Chizuru; Kurita, Osamu; Kubo, Tomoko

    2014-12-01

    The influence of non-Saccharomyces yeast, Kluyveromyces lactis, on metabolite formation and the ethanol tolerance of Saccharomyces cerevisiae in mixed cultures was examined on synthetic minimal medium containing 20% glucose. In the late stage of fermentation after the complete death of K. lactis, S. cerevisiae in mixed cultures was more ethanol-tolerant than that in pure culture. The chronological life span of S. cerevisiae was shorter in pure culture than mixed cultures. The yeast cells of the late stationary phase both in pure and mixed cultures had a low buoyant density with no significant difference in the non-quiescence state between both cultures. In mixed cultures, the glycerol contents increased and the alanine contents decreased when compared with the pure culture of S. cerevisiae. The distinctive intracellular amino acid pool concerning its amino acid concentrations and its amino acid composition was observed in yeast cells with different ethanol tolerance in the death phase. Co-cultivation of K. lactis seems to prompt S. cerevisiae to be ethanol tolerant by forming opportune metabolites such as glycerol and alanine and/or changing the intracellular amino acid pool. Copyright © 2014 Elsevier GmbH. All rights reserved.

  16. Impact of mixed Torulaspora delbrueckii-Saccharomyces cerevisiae culture on high-sugar fermentation.

    Science.gov (United States)

    Bely, Marina; Stoeckle, Philippe; Masneuf-Pomarède, Isabelle; Dubourdieu, Denis

    2008-03-20

    Conventional wine yeasts produce high concentrations of volatile acidity, mainly acetic acid, during high-sugar fermentation. This alcoholic fermentation by-product is highly detrimental to wine quality and, in some cases, levels may even exceed legal limits. In this study, a non-conventional species, Torulaspora delbrueckii, was used, in pure cultures and mixed with Saccharomyces cerevisiae yeast, to ferment botrytized musts. Fermentation rate, biomass growth, and the formation of volatile acidity, acetaldehyde, and glycerol were considered. This study demonstrated that T. delbrueckii, often described as a low acetic producer under standard conditions, retained this quality even in a high-sugar medium. Unlike S. cerevisiae, this species did not respond to the hyper-osmotic medium by increasing acetic production as soon as it is inoculated into the must. Nevertheless, this yeast produced low ethanol and biomass yields, and the fermentation was sluggish. As a result, T. delbrueckii fermentations do not reach the required ethanol content (14%vol.), although this species can survive at this concentration. A mixed culture of T. delbrueckii and S. cerevisiae was the best combination for improving the analytical profile of sweet wine, particularly volatile acidity and acetaldehyde production. A mixed T. delbrueckii/S. cerevisiae culture at a 20:1 ratio produced 53% less in volatile acidity and 60% less acetaldehyde than a pure culture of S. cerevisiae. Inoculating S. cerevisiae after 5 days' fermentation by T. delbrueckii had less effect on volatile acidity and acetaldehyde production and resulted in stuck fermentation. These results contribute to a better understanding of the behaviour of non-Saccharomyces and their potential application in wine industry.

  17. Characterization of methanotrophic bacteria on the basis of intact phospholipid profiles.

    Science.gov (United States)

    Fang, J; Barcelona, M J; Semrau, J D

    2000-08-01

    The intact phospholipid profiles (IPPs) of seven species of methanotrophs from all three physiological groups, type I, II and X, were determined using liquid chromatography/electrospray ionization/mass spectrometry. In these methanotrophs, two major classes of phospholipids were found, phosphatidylglycerol (PG) and phosphatidylethanolamine (PE) as well as its derivatives phosphatidylmethylethanolamine (PME) and phosphatidyldimethylethanolamine (PDME). Specifically, the type I methanotrophs, Methylomonas methanica, Methylomonas rubra and Methylomicrobium album BG8 were characterized by PE and PG phospholipids with predominantly C16:1 fatty acids. The type II methanotrophs, Methylosinus trichosporium OB3b and CSC1 were characterized by phospholipids of PG, PME and PDME with predominantly C18:1 fatty acids. Methylococcus capsulatus Bath, a representative of type X methanotrophs, contained mostly PE (89% of the total phospholipids). Finally, the IPPs of a recently isolated acidophilic methanotroph, Methylocella palustris, showed it had a preponderance of PME phospholipids with 18:1 fatty acids (94% of total). Principal component analysis showed these methanotrophs could be clearly distinguished based on phospholipid profiles. Results from this study suggest that IPP can be very useful in bacterial chemotaxonomy.

  18. Differential Transcriptional Activation of Genes Encoding Soluble Methane Monooxygenase in a Facultative Versus an Obligate Methanotroph.

    Science.gov (United States)

    Smirnova, Angela V; Dunfield, Peter F

    2018-03-06

    Methanotrophs are a specialized group of bacteria that can utilize methane (CH₄) as a sole energy source. A key enzyme responsible for methane oxidation is methane monooxygenase (MMO), of either a soluble, cytoplasmic type (sMMO), or a particulate, membrane-bound type (pMMO). Methylocella silvestris BL2 and Methyloferula stellata AR4 are closely related methanotroph species that oxidize methane via sMMO only. However, Methyloferula stellata is an obligate methanotroph, while Methylocella silvestris is a facultative methanotroph able to grow on several multicarbon substrates in addition to methane. We constructed transcriptional fusions of the mmo promoters of Methyloferula stellata and Methylocella silvestris to a promoterless gfp in order to compare their transcriptional regulation in response to different growth substrates, in the genetic background of both organisms. The following patterns were observed: (1) The mmo promoter of the facultative methanotroph Methylocella silvestris was either transcriptionally downregulated or repressed by any growth substrate other than methane in the genetic background of Methylocella silvetris ; (2) Growth on methane alone upregulated the mmo promoter of Methylocella silvetris in its native background but not in the obligate methanotroph Methyloferula stellata ; (3) The mmo promoter of Methyloferula stellata was constitutive in both organisms regardless of the growth substrate, but with much lower promoter activity than the mmo promoter of Methylocella silvetris . These results support a conclusion that a different mode of transcriptional regulation of sMMO contributes to the facultative lifestyle of Methylocella silvetris compared to the obligate methanotroph Methyloferula stellata .

  19. Differential Transcriptional Activation of Genes Encoding Soluble Methane Monooxygenase in a Facultative Versus an Obligate Methanotroph

    Directory of Open Access Journals (Sweden)

    Angela V. Smirnova

    2018-03-01

    Full Text Available Methanotrophs are a specialized group of bacteria that can utilize methane (CH4 as a sole energy source. A key enzyme responsible for methane oxidation is methane monooxygenase (MMO, of either a soluble, cytoplasmic type (sMMO, or a particulate, membrane-bound type (pMMO. Methylocella silvestris BL2 and Methyloferula stellata AR4 are closely related methanotroph species that oxidize methane via sMMO only. However, Methyloferula stellata is an obligate methanotroph, while Methylocella silvestris is a facultative methanotroph able to grow on several multicarbon substrates in addition to methane. We constructed transcriptional fusions of the mmo promoters of Methyloferula stellata and Methylocella silvestris to a promoterless gfp in order to compare their transcriptional regulation in response to different growth substrates, in the genetic background of both organisms. The following patterns were observed: (1 The mmo promoter of the facultative methanotroph Methylocella silvestris was either transcriptionally downregulated or repressed by any growth substrate other than methane in the genetic background of Methylocella silvetris; (2 Growth on methane alone upregulated the mmo promoter of Methylocella silvetris in its native background but not in the obligate methanotroph Methyloferula stellata; (3 The mmo promoter of Methyloferula stellata was constitutive in both organisms regardless of the growth substrate, but with much lower promoter activity than the mmo promoter of Methylocella silvetris. These results support a conclusion that a different mode of transcriptional regulation of sMMO contributes to the facultative lifestyle of Methylocella silvetris compared to the obligate methanotroph Methyloferula stellata.

  20. Detection, Isolation, and Characterization of Acidophilic Methanotrophs from Sphagnum Mosses ▿ †

    Science.gov (United States)

    Kip, Nardy; Ouyang, Wenjing; van Winden, Julia; Raghoebarsing, Ashna; van Niftrik, Laura; Pol, Arjan; Pan, Yao; Bodrossy, Levente; van Donselaar, Elly G.; Reichart, Gert-Jan; Jetten, Mike S. M.; Sinninghe Damsté, Jaap S.; Op den Camp, Huub J. M.

    2011-01-01

    Sphagnum peatlands are important ecosystems in the methane cycle. Methane-oxidizing bacteria in these ecosystems serve as a methane filter and limit methane emissions. Yet little is known about the diversity and identity of the methanotrophs present in and on Sphagnum mosses of peatlands, and only a few isolates are known. The methanotrophic community in Sphagnum mosses, originating from a Dutch peat bog, was investigated using a pmoA microarray. A high biodiversity of both gamma- and alphaproteobacterial methanotrophs was found. With Sphagnum mosses as the inoculum, alpha- and gammaproteobacterial acidophilic methanotrophs were isolated using established and newly designed media. The 16S rRNA, pmoA, pxmA, and mmoX gene sequences showed that the alphaproteobacterial isolates belonged to the Methylocystis and Methylosinus genera. The Methylosinus species isolated are the first acid-tolerant members of this genus. Of the acidophilic gammaproteobacterial strains isolated, strain M5 was affiliated with the Methylomonas genus, and the other strain, M200, may represent a novel genus, most closely related to the genera Methylosoma and Methylovulum. So far, no acidophilic or acid-tolerant methanotrophs in the Gammaproteobacteria class are known. All strains showed the typical features of either type I or II methanotrophs and are, to the best of our knowledge, the first isolated (acidophilic or acid-tolerant) methanotrophs from Sphagnum mosses. PMID:21724892

  1. Bioleaching of electronic scrap by mixed culture of moderately thermophilic microorganisms

    Science.gov (United States)

    Ivǎnuş, D.; ǎnuş, R. C., IV; Cǎlmuc, F.

    2010-06-01

    A process for the metal recovery from electronic scrap using bacterial leaching was investigated. A mixed culture of moderately thermophilic microorganisms was enriched from acid mine drainages (AMDs) samples collected from several sulphide mines in Romania, and the bioleaching of electronic scrap was conducted both in shake flask and bioreactor. The results show that in the shake flask, the mixture can tolerate 50 g/L scrap after being acclimated to gradually increased concentrations of scrap. The copper extraction increases obviously in bioleaching of scrap with moderately thermophilic microorganisms supplemented with 0.4 g/L yeast extract at 180 r/min, 74% copper can be extracted in the pulp of 50 g/L scrap after 20 d. Compared with copper extractions of mesophilic culture, unacclimated culture and acclimated culture without addition of yeast extract, that of accliniated culture with addition of yeast extract is increased by 53%, 44% and 16%, respectively. In a completely stirred tank reactor, the mass fraction of copper and total iron extraction reach up to 81% and 56%, respectively. The results also indicate that it is necessary to add a large amount of acid to the pulp to extract copper from electronic scrap effectively.

  2. Children's activities and their meanings for parents: a mixed-methods study in six Western cultures.

    Science.gov (United States)

    Harkness, Sara; Zylicz, Piotr Olaf; Super, Charles M; Welles-Nyström, Barbara; Bermúdez, Moisés Ríos; Bonichini, Sabrina; Moscardino, Ughetta; Mavridis, Caroline Johnston

    2011-12-01

    Theoretical perspectives and research in sociology, anthropology, sociolinguistics, and cultural psychology converge in recognizing the significance of children's time spent in various activities, especially in the family context. Knowing how children's time is deployed, however, only gives us a partial answer to how children acquire competence; the other part must take into account the culturally constructed meanings of activities, from the perspective of those who organize and direct children's daily lives. In this article, we report on a study of children's routine daily activities and on the meanings that parents attribute to them in six Western middle-class cultural communities located in Italy, The Netherlands, Poland, Spain, Sweden, and the United States (N = 183). Using week-long time diaries kept by parents, we first demonstrate similarities as well as significant differences in children's daily routines across the cultural samples. We then present brief vignettes--"a day in the life" --of children from each sample. Parent interviews were coded for themes in the meanings attributed to various activities. Excerpts from parent interviews, focusing on four major activities (meals, family time, play, school- or developmentally related activities), are presented to illustrate how cultural meanings and themes are woven into parents' organization and understanding of their children's daily lives. The results of this mixed-method approach provide a more reliable and nuanced picture of children's and families' daily lives than could be derived from either method alone.

  3. Effect of didecyl dimethyl ammonium chloride on nitrate reduction in a mixed methanogenic culture.

    Science.gov (United States)

    Tezel, U; Pierson, J A; Pavlostathis, S G

    2008-01-01

    The effect of the quaternary ammonium compound, didecyl dimethyl ammonium chloride (DDAC), on nitrate reduction was investigated at concentrations up to 100 mg/L in a batch assay using a mixed, mesophilic (35 degrees C) methanogenic culture. Glucose was used as the carbon and energy source and the initial nitrate concentration was 70 mg N/L. Dissimilatory nitrate reduction to ammonia (DNRA) and to dinitrogen (denitrification) were observed at DDAC concentrations up to 25 mg/L. At and above 50 mg DDAC/L, DNRA was inhibited and denitrification was incomplete resulting in accumulation of nitrous oxide. At DDAC concentrations above 10 mg/L, production of nitrous oxide, even transiently, resulted in complete, long-term inhibition of methanogenesis and accumulation of volatile fatty acids. Fermentation was inhibited at and above 75 mg DDAC/L. DDAC suppressed microbial growth and caused cell lysis at a concentration 50 mg/L or higher. Most of the added DDAC was adsorbed on the biomass. Over 96% of the added DDAC was recovered from all cultures at the end of the 100-days incubation period, indicating that DDAC did not degrade in the mixed methanogenic culture under the conditions of this study.

  4. Experimental and mathematical model of the interactions in the mixed culture of links in the "producer-consumer" cycle

    Science.gov (United States)

    Pisman, T. I.; Galayda, Ya. V.

    The paper presents experimental and mathematical model of interactions between invertebrates the ciliates Paramecium caudatum and the rotifers Brachionus plicatilis and algae Chlorella vulgaris and Scenedesmus quadricauda in the producer -- consumer aquatic biotic cycle with spatially separated components The model describes the dynamics of the mixed culture of ciliates and rotifers in the consumer component feeding on the mixed algal culture of the producer component It has been found that metabolites of the algae Scenedesmus produce an adverse effect on the reproduction of the ciliates P caudatum Taking into account this effect the results of investigation of the mathematical model were in qualitative agreement with the experimental results In the producer -- consumer biotic cycle it was shown that coexistence is impossible in the mixed algal culture of the producer component and in the mixed culture of invertebrates of the consumer component The ciliates P caudatum are driven out by the rotifers Brachionus plicatilis

  5. Stable acetate production in extreme-thermophilic (70ºC) mixed culture fermentation by selective enrichment of hydrogenotrophic methanogens

    NARCIS (Netherlands)

    Zhang, F.; Zhang, Y.; Ding, J.; Dai, K.; Van Loosdrecht, M.C.M.; Zeng, R.J.

    2014-01-01

    The control of metabolite production is difficult in mixed culture fermentation. This is particularly related to hydrogen inhibition. In this work, hydrogenotrophic methanogens were selectively enriched to reduce the hydrogen partial pressure and to realize efficient acetate production in

  6. Coupled nutrient removal and biomass production with mixed algal culture: impact of biotic and abiotic factors.

    Science.gov (United States)

    Su, Yanyan; Mennerich, Artur; Urban, Brigitte

    2012-08-01

    The influence of biotic (algal inoculum concentration) and abiotic factors (illumination cycle, mixing velocity and nutrient strength) on the treatment efficiency, biomass generation and settleability were investigated with selected mixed algal culture. Dark condition led to poor nutrient removal efficiency. No significant difference in the N, P removal and biomass settleability between continuous and alternating illumination was observed, but a higher biomass generation capability for the continuous illumination was obtained. Different mixing velocity led to similar phosphorus removal efficiencies (above 98%) with different retention times. The reactor with 300 rpm mixing velocity had the best N removal capability. For the low strength wastewater, the N rates were 5.4±0.2, 9.1±0.3 and 10.8±0.3 mg/l/d and P removal rates were 0.57±0.03, 0.56±0.03 and 0.72±0.05 mg/l/d for reactors with the algal inoculum concentration of 0.2, 0.5 and 0.8 g/l, respectively. Low nutrient removal efficiency and poor biomass settleability were obtained for high strength wastewater. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Hydrogen production characteristics of the organic fraction of municipal solid wastes by anaerobic mixed culture fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Li; Yu, Zhang [Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China)]|[Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Zhenhong, Yuan; Yongming, Sun; Xiaoying, Kong [Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2009-01-15

    The hydrogen production from the organic fraction of municipal solid waste (OFMSW) by anaerobic mixed culture fermentation was investigated using batch experiments at 37 C. Seven varieties of typical individual components of OFMSW including rice, potato, lettuce, lean meat, oil, fat and banyan leaves were selected to estimate the hydrogen production potential. Experimental results showed that the boiling treated anaerobic sludge was effective mixed inoculum for fermentative hydrogen production from OFMSW. Mechanism of fermentative hydrogen production indicates that, among the OFMSW, carbohydrates is the most optimal substrate for fermentative hydrogen production compared with proteins, lipids and lignocelluloses. This conclusion was also substantiated by experimental results of this study. The hydrogen production potentials of rice, potato and lettuce were 134 mL/g-VS, 106 mL/g-VS, and 50 mL/g-VS respectively. The hydrogen percentages of the total gas produced from rice, potato and lettuce were 57-70%, 41-55% and 37-67%. (author)

  8. Slow conduction in mixed cultured strands of primary ventricular cells and stem cell-derived cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Jan Pavel Kucera

    2015-09-01

    Full Text Available Modern concepts for the treatment of myocardial diseases focus on novel cell therapeutic strategies involving stem cell-derived cardiomyocytes (SCMs. However, functional integration of SCMs requires similar electrophysiological properties as primary cardiomyocytes (PCMs and the ability to establish intercellular connections with host myocytes in order to contribute to the electrical and mechanical activity of the heart. The aim of this project was to investigate the properties of cardiac conduction in a co-culture approach using SCMs and PCMs in cultured cell strands. Murine embryonic SCMs were pooled with fetal ventricular cells and seeded in predefined proportions on microelectrode arrays to form patterned strands of mixed cells. Conduction velocity (CV was measured during steady state pacing. SCM excitability was estimated from action potentials measured in single cells using the patch clamp technique. Experiments were complemented with computer simulations of conduction using a detailed model of cellular architecture in mixed cell strands.CV was significantly lower in strands composed purely of SCMs (5.5±1.5 cm/s, n=11 as compared to PCMs (34.9±2.9 cm/s, n=21 at similar refractoriness (100% SCMs: 122±25 ms, n=9; 100% PCMs: 139±67 ms, n=14. In mixed strands combining both cell types, CV was higher than in pure SCMs strands, but always lower than in 100% PCM strands. Computer simulations demonstrated that both intercellular coupling and electrical excitability limit CV.These data provide evidence that in cultures of murine ventricular cardiomyocytes, SCMs cannot restore CV to control levels resulting in slow conduction, which may lead to reentry circuits and arrhythmias.

  9. Enhanced xylitol production: Expression of xylitol dehydrogenase from Gluconobacter oxydans and mixed culture of resting cell.

    Science.gov (United States)

    Qi, Xiang-Hui; Zhu, Jing-Fei; Yun, Jun-Hua; Lin, Jing; Qi, Yi-Lin; Guo, Qi; Xu, Hong

    2016-09-01

    Xylitol has numerous applications in food and pharmaceutical industry, and it can be biosynthesized by microorganisms. In the present study, xdh gene, encoding xylitol dehydrogenase (XDH), was cloned from the genome of Gluconobacter oxydans CGMCC 1.49 and overexpressed in Escherichia coli BL21. Sequence analysis revealed that XDH has a TGXXGXXG NAD(H)-binding motif and a YXXXK active site motif, and belongs to the short-chain dehydrogenase/reductase family. And then, the enzymatic properties and kinetic parameter of purified recombinant XDH were investigated. Subsequently, transformations of xylitol from d-xylulose and d-arabitol, respectively, were studied through mixed culture of resting cells of G. oxydans wild-type strain and recombinant strain BL21-xdh. We obtained 28.80 g/L xylitol by mixed culture from 30 g/L d-xylulose in 28 h. The production was increased by more than three times as compared with that of wild-type strain. Furthermore, 25.10 g/L xylitol was produced by the mixed culture from 30 g/L d-arabitol in 30 h with a yield of 0.837 g/g, and the max volumetric productivity of 0.990 g/L h was obtained at 22 h. These contrast to the fact that wild-type strain G. oxydans only produced 8.10 g/L xylitol in 30 h with a yield of 0.270 g/g. To our knowledge, these values are the highest among the reported yields and productivity efficiencies of xylitol from d-arabitol with engineering strains. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  10. Direct conversion of sorghum carbohydrates to ethanol by a mixed microbial culture

    Energy Technology Data Exchange (ETDEWEB)

    Christakopoulos, Paul; Lianwu Li; Kekos, Dimitris; Macris, B.J. (National Technical Univ. of Athens (Greece). Dept. of Chemical Engineering)

    1993-01-01

    The carbohydrates of sweet sorghum were directly converted to ethanol by a mixed culture of Fusarium oxysporum F3 and Saccharomyces cerevisiae 2541. A number of factors affecting this bioconversion was studied. Optimum ethanol yields of 33.2 g/100 g of total sorghum carbohydrates, corresponding to 10.3 g/100 g of fresh stalks, were obtained. These values represented 68.6% of the theoretical yield based on total polysaccharides and exceeded that based on oligosaccharides of sorghum by 53.7%. The results demonstrated that more than half of the sorghum polysaccharides were directly fermented to ethanol, thus making the process worthy of further investigation. (author)

  11. Comparative life cycle assessment and financial analysis of mixed culture polyhydroxyalkanoate production.

    Science.gov (United States)

    Gurieff, Nicholas; Lant, Paul

    2007-12-01

    A life cycle assessment and financial analysis of mixed culture PHA (PHA(MC)) and biogas production was undertaken based on treating an industrial wastewater. Internal rate of return (IRR) and non-renewable CO(2)eq emissions were used to quantify financial viability and environmental impact. PHA(MC) was preferable to biogas production for treating the specified industrial effluent. PHA(MC) was also financially attractive in comparison to pure culture PHA production. Both PHA production processes had similar environmental impacts that were significantly lower than HDPE production. A large potential for optimisation exists for the PHA(MC) process as financial and environmental costs were primarily due to energy use for downstream processing. Under the conditions used in this work PHA(MC) was shown to be a viable biopolymer production process and an effective industrial wastewater treatment technology. This is the first study of its kind and provides valuable insight into the PHA(MC) process.

  12. Primary microglia isolation from mixed glial cell cultures of neonatal rat brain tissue.

    Science.gov (United States)

    Tamashiro, Tami T; Dalgard, Clifton Lee; Byrnes, Kimberly R

    2012-08-15

    Microglia account for approximately 12% of the total cellular population in the mammalian brain. While neurons and astrocytes are considered the major cell types of the nervous system, microglia play a significant role in normal brain physiology by monitoring tissue for debris and pathogens and maintaining homeostasis in the parenchyma via phagocytic activity. Microglia are activated during a number of injury and disease conditions, including neurodegenerative disease, traumatic brain injury, and nervous system infection. Under these activating conditions, microglia increase their phagocytic activity, undergo morpohological and proliferative change, and actively secrete reactive oxygen and nitrogen species, pro-inflammatory chemokines and cytokines, often activating a paracrine or autocrine loop. As these microglial responses contribute to disease pathogenesis in neurological conditions, research focused on microglia is warranted. Due to the cellular heterogeneity of the brain, it is technically difficult to obtain sufficient microglial sample material with high purity during in vivo experiments. Current research on the neuroprotective and neurotoxic functions of microglia require a routine technical method to consistently generate pure and healthy microglia with sufficient yield for study. We present, in text and video, a protocol to isolate pure primary microglia from mixed glia cultures for a variety of downstream applications. Briefly, this technique utilizes dissociated brain tissue from neonatal rat pups to produce mixed glial cell cultures. After the mixed glial cultures reach confluency, primary microglia are mechanically isolated from the culture by a brief duration of shaking. The microglia are then plated at high purity for experimental study. The principle and protocol of this methodology have been described in the literature. Additionally, alternate methodologies to isolate primary microglia are well described. Homogenized brain tissue may be separated

  13. Selective effects of alpha interferon on human T-lymphocyte subsets during mixed lymphocyte cultures

    DEFF Research Database (Denmark)

    Hokland, M; Hokland, P; Heron, I

    1983-01-01

    Mixed lymphocyte reaction (MLR) cultures of human lymphocyte subsets with or without the addition of physiological doses of human alpha interferon (IFN-alpha) were compared with respect to surface marker phenotypes and proliferative capacities of the responder cells. A selective depression on the T...... T4 cells and decreased numbers of T4 cells harvested from IFN MLRs (days 5-6 of culture). In contrast, it was shown that the T8 (cytotoxic/suppressor) subset in MLRs was either not affected or slightly stimulated by the addition of IFN. The depression of the T4 cells by IFN was accompanied...... by a decrease in the number of activated T cells expressing Ia antigens. On the other hand, IFN MLRs contained greater numbers of cells expressing the T10 differentiation antigen. In experiments with purified T-cell subsets the IFN effect was exerted directly on the T4 cells and not mediated by either T8...

  14. Dark fermentative hydrogen production by defined mixed microbial cultures immobilized on ligno-cellulosic waste materials

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Sanjay K.S. [Microbial Biotechnology and Genomics, Institute of Genomics and Integrative Biology (IGIB), CSIR, Delhi University Campus, Mall Road, Delhi 110007 (India); Department of Biotechnology, University of Pune, Pune 411007 (India); Purohit, Hemant J. [Environmental Genomics Unit, National Environmental Engineering Research Institute (NEERI), CSIR, Nehru Marg, Nagpur 440020 (India); Kalia, Vipin C. [Microbial Biotechnology and Genomics, Institute of Genomics and Integrative Biology (IGIB), CSIR, Delhi University Campus, Mall Road, Delhi 110007 (India)

    2010-10-15

    Mixed microbial cultures (MMCs) based on 11 isolates belonging to Bacillus spp. (Firmicutes), Bordetella avium, Enterobacter aerogenes and Proteus mirabilis (Proteobacteria) were employed to produce hydrogen (H{sub 2}) under dark fermentative conditions. Under daily fed culture conditions (hydraulic retention time of 2 days), MMC6 and MMC4, immobilized on ligno-cellulosic wastes - banana leaves and coconut coir evolved 300-330 mL H{sub 2}/day. Here, H{sub 2} constituted 58-62% of the total biogas evolved. It amounted to a H{sub 2} yield of 1.54-1.65 mol/mol glucose utilized over a period of 60 days of fermentation. The involvement of various Bacillus spp. -Bacillus sp., Bacillus cereus, Bacillus megaterium, Bacillus pumilus and Bacillus thuringiensis as components of the defined MMCs for H{sub 2} production has been reported here for the first time. (author)

  15. From Axenic to Mixed Cultures: Technological Advances Accelerating a Paradigm Shift in Microbiology.

    Science.gov (United States)

    Nai, Corrado; Meyer, Vera

    2018-06-01

    Since the onset of microbiology in the late 19th century, scientists have been growing microorganisms almost exclusively as pure cultures, resulting in a limited and biased view of the microbial world. Only a paradigm shift in cultivation techniques - from axenic to mixed cultures - can allow a full comprehension of the (chemical) communication of microorganisms, with profound consequences for natural product discovery, microbial ecology, symbiosis, and pathogenesis, to name a few areas. Three main technical advances during the last decade are fueling the realization of this revolution in microbiology: microfluidics, next-generation 3D-bioprinting, and single-cell metabolomics. These technological advances can be implemented for large-scale, systematic cocultivation studies involving three or more microorganisms. In this review, we present recent trends in microbiology tools and discuss how these can be employed to decode the chemical language that microorganisms use to communicate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. [Methanotrophs and methylobacteria are found in woody plant tissues within a winter period].

    Science.gov (United States)

    Doronina, N V; Ivanova, E G; Suzina, N F; Trotsenko, Iu A

    2004-01-01

    Samples of tree seeds, buds, and needles collected within a winter period at ambient temperatures from -11 to -17 degrees C were analyzed for the presence of methylotrophic microflora. Thin sections of blue spruce needles were found to contain bacteria morphologically close to pink-pigmented methylobacteria. The methylobacteria that were isolated in pure cultures from samples of linden seeds and buds, pine and blue spruce needles, as well as of lilac, maple, and apple buds, were classified into the genera Methylobacterium and Paracoccus based on the data of morphological studies, enzyme assay, and DNA-DNA hybridization analysis. The methanotrophs that were isolated in pure cultures from samples of linden buds and blue spruce needles were identified into the genus Methylocystis based on the data of morphological studies, enzyme assay, DNA-DNA hybridization, and the phylogenetic analysis of the particulate methane monooxygenase gene pmoA sequences. The inference is made that aerobic methylotrophic bacteria are permanently associated with plants. At the beginning of the vegetative period in spring, the phyllosphere of coniferous and deciduous trees is colonized by the methylotrophic bacteria that have wintered inside plant tissues.

  17. Interaction of polybrominated diphenyl ethers (PBDEs) with anaerobic mixed bacterial cultures isolated from river sediment

    Energy Technology Data Exchange (ETDEWEB)

    Yen, J H; Liao, W C; Chen, W C [Department of Agricultural Chemistry, National Taiwan University, 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Wang, Y.S., E-mail: yswang@ntu.edu.tw [Department of Agricultural Chemistry, National Taiwan University, 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China)

    2009-06-15

    The degradation of flame retardant polybrominated diphenyl ethers (PBDE), including tetra-brominated diphenyl ether (BDE-47), penta-brominated diphenyl ether (BDE-99 and -100), and hexa-brominated diphenyl ether (BDE-153 and -154), by anaerobic bacterial mixed cultures isolated from river sediment was investigated. The effects of PBDEs on changes of anaerobic bacterial community in sediment culture were also studied. Sediments were collected from Er-Jen River and Nan-Kan River basins, which were both heavily polluted rivers in Taiwan, and bacteria from the sediment samples were enriched before the experiment was conducted. Into the anaerobic bacterial mixed cultures, 0.1 {mu}g/mL of PBDEs was added followed by incubation under 30 deg. C for 70 days. Residues of PBDE were determined by gas chromatography with electron capture detector (GC-ECD), and the changes of bacterial community were analyzed by denaturing gradient gel electrophoresis (DGGE). Less than 20% of PBDEs were degraded after 70 days of incubation in all samples except for BDE-47 from the Nan-Kan River sediment. In that culture, BDE-47 was found to have notably degraded. In particular, after 42 days of incubation; BDE-47 was degraded, suddenly and sharply, to a negligible level on Day 70, and the result was confirmed by a repeated experiment. An interesting result was that although BDE-47 was degraded fast in the Nan-Kan River sediment, the bacterial communities did not shift significantly as we had speculated at Day 70. From UPGMA dendrograms, PBDEs changed the composition of bacterial communities, and the extents varied with the variety of PBDE congeners. By the amendment with BDE-153 or -154, bacterial communities would be changed immediately and irreversibly throughout the rest of the incubation period. No significant difference in degradation of PBDEs was observed between sediment bacteria from Er-Jen River and Nan-Kan River. However, the results verified the persistence of PBDEs in the environment.

  18. Interaction of polybrominated diphenyl ethers (PBDEs) with anaerobic mixed bacterial cultures isolated from river sediment

    International Nuclear Information System (INIS)

    Yen, J.H.; Liao, W.C.; Chen, W.C.; Wang, Y.S.

    2009-01-01

    The degradation of flame retardant polybrominated diphenyl ethers (PBDE), including tetra-brominated diphenyl ether (BDE-47), penta-brominated diphenyl ether (BDE-99 and -100), and hexa-brominated diphenyl ether (BDE-153 and -154), by anaerobic bacterial mixed cultures isolated from river sediment was investigated. The effects of PBDEs on changes of anaerobic bacterial community in sediment culture were also studied. Sediments were collected from Er-Jen River and Nan-Kan River basins, which were both heavily polluted rivers in Taiwan, and bacteria from the sediment samples were enriched before the experiment was conducted. Into the anaerobic bacterial mixed cultures, 0.1 μg/mL of PBDEs was added followed by incubation under 30 deg. C for 70 days. Residues of PBDE were determined by gas chromatography with electron capture detector (GC-ECD), and the changes of bacterial community were analyzed by denaturing gradient gel electrophoresis (DGGE). Less than 20% of PBDEs were degraded after 70 days of incubation in all samples except for BDE-47 from the Nan-Kan River sediment. In that culture, BDE-47 was found to have notably degraded. In particular, after 42 days of incubation; BDE-47 was degraded, suddenly and sharply, to a negligible level on Day 70, and the result was confirmed by a repeated experiment. An interesting result was that although BDE-47 was degraded fast in the Nan-Kan River sediment, the bacterial communities did not shift significantly as we had speculated at Day 70. From UPGMA dendrograms, PBDEs changed the composition of bacterial communities, and the extents varied with the variety of PBDE congeners. By the amendment with BDE-153 or -154, bacterial communities would be changed immediately and irreversibly throughout the rest of the incubation period. No significant difference in degradation of PBDEs was observed between sediment bacteria from Er-Jen River and Nan-Kan River. However, the results verified the persistence of PBDEs in the environment.

  19. Organizational culture change in U.S. hospitals: a mixed methods longitudinal intervention study.

    Science.gov (United States)

    Curry, Leslie A; Linnander, Erika L; Brewster, Amanda L; Ting, Henry; Krumholz, Harlan M; Bradley, Elizabeth H

    2015-03-07

    Improving outcomes for patients with acute myocardial infarction (AMI) is a priority for hospital leadership, clinicians, and policymakers. Evidence suggests links between hospital organizational culture and hospital performance; however, few studies have attempted to shift organizational culture in order to improve performance, fewer have focused on patient outcomes, and none have addressed mortality for patients with AMI. We sought to address this gap through a novel longitudinal intervention study, Leadership Saves Lives (LSL). This manuscript describes the methodology of LSL, a 2-year intervention study using a concurrent mixed methods design, guided by open systems theory and the Assess, Innovate, Develop, Engage, Devolve (AIDED) model of diffusion, implemented in 10 U.S. hospitals and their peer hospital networks. The intervention has three primary components: 1) annual convenings of the ten intervention hospitals; 2) semiannual workshops with guiding coalitions at each hospital; and 3) continuous remote support across all intervention hospitals through a web-based platform. Primary outcomes include 1) shifts in key dimensions of hospital organizational culture associated with lower mortality rates for patients with AMI; 2) use of targeted evidence-based practices associated with lower mortality rates for patients with AMI; and 3) in-hospital AMI mortality. Quantitative data include annual surveys of guiding coalition members in the intervention hospitals and peer network hospitals. Qualitative data include in-person, in-depth interviews with all guiding coalition members and selective observations of key interactions in care for patients with AMI, collected at three time points. Data integration will identify patterns and major themes in change processes across all intervention hospitals over time. LSL is novel in its use of a longitudinal mixed methods approach in a diverse sample of hospitals, its focus on objective outcome measures of mortality, and its

  20. Starter Culture Selection for Making Chinese Sesame-Flavored Liquor Based on Microbial Metabolic Activity in Mixed-Culture Fermentation

    Science.gov (United States)

    Wu, Qun; Ling, Jie

    2014-01-01

    Selection of a starter culture with excellent viability and metabolic activity is important for inoculated fermentation of traditional food. To obtain a suitable starter culture for making Chinese sesame-flavored liquor, the yeast and bacterium community structures were investigated during spontaneous and solid-state fermentations of this type of liquor. Five dominant species in spontaneous fermentation were identified: Saccharomyces cerevisiae, Pichia membranaefaciens, Issatchenkia orientalis, Bacillus licheniformis, and Bacillus amyloliquefaciens. The metabolic activity of each species in mixed and inoculated fermentations of liquor was investigated in 14 different cocultures that used different combinations of these species. The relationships between the microbial species and volatile metabolites were analyzed by partial least-squares (PLS) regression analysis. We found that S. cerevisiae was positively correlated to nonanal, and B. licheniformis was positively associated with 2,3-butanediol, isobutyric acid, guaiacol, and 4-vinyl guaiacol, while I. orientalis was positively correlated to butyric acid, isovaleric acid, hexanoic acid, and 2,3-butanediol. These three species are excellent flavor producers for Chinese liquor. Although P. membranaefaciens and B. amyloliquefaciens were not efficient flavor producers, the addition of them alleviated competition among the other three species and altered their growth rates and flavor production. As a result, the coculture of all five dominant species produced the largest amount of flavor compounds. The result indicates that flavor producers and microbial interaction regulators are important for inoculated fermentation of Chinese sesame-flavored liquor. PMID:24814798

  1. Mixed culture polyhydroxyalkanoates production from sugar molasses: the use of a 2-stage CSTR system for culture selection.

    Science.gov (United States)

    Albuquerque, M G E; Concas, S; Bengtsson, S; Reis, M A M

    2010-09-01

    Polyhydroxyalkanoates (PHAs) are promising biodegradable polymers. The use of mixed microbial cultures (MMC) and low cost feedstocks have a positive impact on the cost-effectiveness of the process. It has typically been carried out in Sequencing Batch Reactors (SBR). In this study, a 2-stage CSTR system (under Feast and Famine conditions) was used to effectively select for PHA-storing organisms using fermented molasses as feedstock. The effect of influent substrate concentration (60-120 Cmmol VFA/L) and HRT ratio between the reactors (0.2-0.5h/h) on the system's selection efficiency was assessed. It was shown that Feast reactor residual substrate concentration impacted on the selective pressure for PHA storage (due to substrate-dependent kinetic limitation). Moreover, a residual substrate concentration coming from the Feast to the Famine reactor did not jeopardize the physiological adaptation required for enhanced PHA storage. The culture reached a maximum PHA content of 61%. This success opens new perspectives to the use of wastewater treatment infrastructure for PHA production, thus valorizing either excess sludge or wastewaters. Copyright 2010 Elsevier Ltd. All rights reserved.

  2. Generalist palliative care in hospital - Cultural and organisational interactions. Results of a mixed-methods study.

    Science.gov (United States)

    Bergenholtz, Heidi; Jarlbaek, Lene; Hølge-Hazelton, Bibi

    2016-06-01

    It can be challenging to provide generalist palliative care in hospitals, owing to difficulties in integrating disease-oriented treatment with palliative care and the influences of cultural and organisational conditions. However, knowledge on the interactions that occur is sparse. To investigate the interactions between organisation and culture as conditions for integrated palliative care in hospital and, if possible, to suggest workable solutions for the provision of generalist palliative care. A convergent parallel mixed-methods design was chosen using two independent studies: a quantitative study, in which three independent datasets were triangulated to study the organisation and evaluation of generalist palliative care, and a qualitative, ethnographic study exploring the culture of generalist palliative nursing care in medical departments. A Danish regional hospital with 29 department managements and one hospital management. Two overall themes emerged: (1) 'generalist palliative care as a priority at the hospital', suggesting contrasting issues regarding prioritisation of palliative care at different organisational levels, and (2) 'knowledge and use of generalist palliative care clinical guideline', suggesting that the guideline had not reached all levels of the organisation. Contrasting issues in the hospital's provision of generalist palliative care at different organisational levels seem to hamper the interactions between organisation and culture - interactions that appear to be necessary for the provision of integrated palliative care in the hospital. The implementation of palliative care is also hindered by the main focus being on disease-oriented treatment, which is reflected at all the organisational levels. © The Author(s) 2015.

  3. Environmental distribution and abundance of the facultative methanotroph Methylocella.

    Science.gov (United States)

    Rahman, Md Tanvir; Crombie, Andrew; Chen, Yin; Stralis-Pavese, Nancy; Bodrossy, Levente; Meir, Patrick; McNamara, Niall P; Murrell, J Colin

    2011-06-01

    Methylocella spp. are facultative methanotrophs, which are able to grow not only on methane but also on multicarbon substrates such as acetate, pyruvate or malate. Methylocella spp. were previously thought to be restricted to acidic soils such as peatlands, in which they may have a key role in methane oxidation. There is little information on the abundance and distribution of Methylocella spp. in the environment. New primers were designed, and a real-time quantitative PCR method was developed and validated targeting Methylocella mmoX (encoding the α-subunit of the soluble methane monooxygenase) that allowed the quantification of Methylocella spp. in environmental samples. We also developed and validated specific PCR assays, which target 16S rRNA genes of known Methylocella spp. These were used to investigate the distribution of Methylocella spp. in a variety of environmental samples. It was revealed that Methylocella species are widely distributed in nature and not restricted to acidic environments.

  4. Comparison of n-eicosane and phenanthrene removal by pure and mixed cultures of two marine bacteria

    International Nuclear Information System (INIS)

    Syakti, A.D.; Acquaviva, M.; Gilewicz, M.; Doumenq, P.; Bertrand, J.C.

    2004-01-01

    The biotransformation activities of two hydrocarbonoclastic marine bacteria, Corynebacterium sp. and Sphingomonas sp. 2MPII, on n-eicosane and phenanthrene were investigated. During a 56-day experiment, in pure and mixed cultures, Corynebacterium sp. and Sphingomonas sp. 2MPII removed about 70% of the initial n-eicosane and phenanthrene concentrations (1 and 0.4 g L -1 , respectively). In pure cultures, culturable cell abundances increased over time, from 0.8 to 8.6x10 -11 CFU L -1 (Corynebacterium sp.) and from 2.1 to 16x10 -11 CFU L -1 (Sphingomonas sp. 2MPII ) but remained barely constant in mixed cultures. We defined a biotransformation index based on the number of culturable cells rather than the culture protein content, with the biotransformation cell yield (BCY) expressed in grams hydrocarbon CFU -1 per day to better characterize hydrocarbon removal in pure and mixed cultures. The BCY was markedly higher in mixed than in pure cultures, increasing by a factor of 2-10.7 and 2.3-4.7 for n-eicosane and phenanthrene removal, respectively

  5. Assessing Adolescents' Understanding of and Reactions to Stress in Different Cultures: Results of a Mixed-Methods Approach

    Science.gov (United States)

    Nastasi, Bonnie K.; Hitchcock, John H.; Burkholder, Gary; Varjas, Kristen; Sarkar, Sreeroopa; Jayasena, Asoka

    2007-01-01

    This article expands on an emerging mixed-method approach for validating culturally-specific constructs (see Hitchcock et al., 2005). Previous work established an approach for dealing with cultural impacts when assessing psychological constructs and the current article extends these efforts into studying stress reactions among adolescents in Sri…

  6. [Research progress and discovery process of facultative methanotrophs--a review].

    Science.gov (United States)

    Zhao, Tiantao; Xing, Zhilin; Zhang, Lijie

    2013-08-04

    Facultative methanotrophs are a group of phylogenetically diverse microorganisms characterized by their ability to use methane and some other compounds containing C-C bond as their sole source of carbon and energy. Recently, which belong to the facultative methanotrophs in the genera Methylocella, Methylocapsa and Methylocystis, which belong to the Alphaproteobacteria, have been reported that can grow on larger organic acids or ethanol for some species, as well as methane. In this paper, the research history of facultative methanotrophs was summarized systematically, some other facultative methane-oxidizing microorganisms were introduced, the metabolic mechanisms of utilizing multi-carbon compounds by facultative methanotrophs were analyzed, and the current problems and the future engineering applications were discussed.

  7. Biological conversion of biogas to methanol using methanotrophs isolated from solid-state anaerobic digestate.

    Science.gov (United States)

    Sheets, Johnathon P; Ge, Xumeng; Li, Yueh-Fen; Yu, Zhongtang; Li, Yebo

    2016-02-01

    The aim of this work was to isolate methanotrophs (methane oxidizing bacteria) that can directly convert biogas produced at a commercial anaerobic digestion (AD) facility to methanol. A methanotrophic bacterium was isolated from solid-state anaerobic digestate. The isolate had characteristics comparable to obligate methanotrophs from the genus Methylocaldum. This newly isolated methanotroph grew on biogas or purified CH4 and successfully converted biogas from AD to methanol. Methanol production was achieved using several methanol dehydrogenase (MDH) inhibitors and formate as an electron donor. The isolate also produced methanol using phosphate with no electron donor or using formate with no MDH inhibitor. The maximum methanol concentration (0.43±0.00gL(-1)) and 48-h CH4 to methanol conversion (25.5±1.1%) were achieved using biogas as substrate and a growth medium containing 50mM phosphate and 80mM formate. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Production of D- and L-Lactic Acid by Mono- and Mixed Cultures of Lactobacillus sp.

    Directory of Open Access Journals (Sweden)

    Antonija Trontel

    2011-01-01

    Full Text Available Batch cultivation of monoculture of Lactobacillus sp. and two–strain mixed culture of Lactobacillus sp. and Lactobacillus amylovorus DSM 20531T was carried out with the aim of producing L-(+- and D-(–/L-(+-lactic acid to be implemented in poly(lactic acid polymer production. Metabolic capacity of two Lactobacillus strains to ferment different carbon sources (glucose, sucrose or soluble starch during cultivation in MRS medium at 40 °C, in a laboratory-scale stirred tank bioreactor was defined. Lactobacillus sp. showed similar affinity towards mono- and disaccharide substrates, which were homofermentatively converted mostly to L-(+-lactic acid. L. amylovorus DSM 20531T has been characterized as a D/L-lactate producer and it is capable of conducting simultaneous saccharification and fermentation. Due to the interaction of Lactobacillus sp. with L. amylovorus DSM 20531T, starch was hydrolysed and fermented to the mixture of L-(+- and D-(–-lactic acid. Modified Luedeking-Piret kinetics used for the description of substrate utilization, growth of mono- and mixed cultures and production of lactic acid stereoisomers showed good agreement with experimental data.

  9. Electrochemically Driven Fermentation of Organic Substrates with Undefined Mixed Microbial Cultures.

    Science.gov (United States)

    Villano, Marianna; Paiano, Paola; Palma, Enza; Miccheli, Alfredo; Majone, Mauro

    2017-08-10

    Growing scientific interest in mixed microbial culture-based anaerobic biotechnologies for the production of value-added chemicals and fuels from organic waste residues requires a parallel focus on the development and implementation of strategies to control the distribution of products. This study examined the feasibility of an electrofermentation approach, based on the introduction of a polarized (-700 mV vs. the standard hydrogen electrode) graphite electrode in the fermentation medium, to steer the product distribution during the conversion of organic substrates (glucose, ethanol, and acetate supplied as single compounds or in mixtures) by undefined mixed microbial cultures. In batch experiments, the polarized electrode triggered a nearly 20-fold increase (relative to open circuit controls) in the yield of isobutyrate production (0.43±0.01 vs. 0.02±0.02 mol mol -1 glucose) during the anaerobic fermentation of the ternary mixture of substrates, without adversely affecting the rate of substrate bioconversion. The observed change in the fermentative metabolism was most likely triggered by the (potentiostatic) regulation of the oxidation-reduction potential of the reaction medium rather than by the electrode serving as an electron donor. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Mixed

    Directory of Open Access Journals (Sweden)

    Pau Baya

    2011-05-01

    Full Text Available Remenat (Catalan (Mixed, "revoltillo" (Scrambled in Spanish, is a dish which, in Catalunya, consists of a beaten egg cooked with vegetables or other ingredients, normally prawns or asparagus. It is delicious. Scrambled refers to the action of mixing the beaten egg with other ingredients in a pan, normally using a wooden spoon Thought is frequently an amalgam of past ideas put through a spinner and rhythmically shaken around like a cocktail until a uniform and dense paste is made. This malleable product, rather like a cake mixture can be deformed pulling it out, rolling it around, adapting its shape to the commands of one’s hands or the tool which is being used on it. In the piece Mixed, the contortion of the wood seeks to reproduce the plasticity of this slow heavy movement. Each piece lays itself on the next piece consecutively like a tongue of incandescent lava slowly advancing but with unstoppable inertia.

  11. Culture and mixed emotions: co-occurrence of positive and negative emotions in Japan and the United States.

    Science.gov (United States)

    Miyamoto, Yuri; Uchida, Yukiko; Ellsworth, Phoebe C

    2010-06-01

    Previous cross-cultural comparisons of correlations between positive and negative emotions found that East Asians are more likely than Americans to feel dialectical emotions. However, not much is known about the co-occurrence of positive and negative emotions in a given situation. When asked to describe situations in which they felt mixed emotions, Japanese and American respondents listed mostly similar situations. By presenting these situations to another group of respondents, we found that Japanese reported more mixed emotions than Americans in the predominantly pleasant situations, whereas there were no cultural differences in mixed emotions in the predominantly unpleasant situations or the mixed situations. The appraisal of self-agency mediated cultural differences in mixed emotions in the predominantly pleasant situations. Study 2 replicated the findings by asking participants to recall how they felt in their past pleasant, unpleasant, and mixed situations. The findings suggest that both Americans and Japanese feel mixed emotions, but the kinds of situation in which they typically do so depends on culture.

  12. Complete genome sequence of the aerobic facultative methanotroph Methylocella silvestris BL2.

    Science.gov (United States)

    Chen, Yin; Crombie, Andrew; Rahman, M Tanvir; Dedysh, Svetlana N; Liesack, Werner; Stott, Matthew B; Alam, Maqsudul; Theisen, Andreas R; Murrell, J Colin; Dunfield, Peter F

    2010-07-01

    Methylocella silvestris BL2 is an aerobic methanotroph originally isolated from an acidic forest soil in Germany. It is the first fully authenticated facultative methanotroph. It grows not only on methane and other one-carbon (C(1)) substrates, but also on some compounds containing carbon-carbon bonds, such as acetate, pyruvate, propane, and succinate. Here we report the full genome sequence of this bacterium.

  13. Complete Genome Sequence of the Aerobic Facultative Methanotroph Methylocella silvestris BL2▿

    Science.gov (United States)

    Chen, Yin; Crombie, Andrew; Rahman, M. Tanvir; Dedysh, Svetlana N.; Liesack, Werner; Stott, Matthew B.; Alam, Maqsudul; Theisen, Andreas R.; Murrell, J. Colin; Dunfield, Peter F.

    2010-01-01

    Methylocella silvestris BL2 is an aerobic methanotroph originally isolated from an acidic forest soil in Germany. It is the first fully authenticated facultative methanotroph. It grows not only on methane and other one-carbon (C1) substrates, but also on some compounds containing carbon-carbon bonds, such as acetate, pyruvate, propane, and succinate. Here we report the full genome sequence of this bacterium. PMID:20472789

  14. Complete Genome Sequence of the Aerobic Facultative Methanotroph Methylocella silvestris BL2▿

    OpenAIRE

    Chen, Yin; Crombie, Andrew; Rahman, M. Tanvir; Dedysh, Svetlana N.; Liesack, Werner; Stott, Matthew B.; Alam, Maqsudul; Theisen, Andreas R.; Murrell, J. Colin; Dunfield, Peter F.

    2010-01-01

    Methylocella silvestris BL2 is an aerobic methanotroph originally isolated from an acidic forest soil in Germany. It is the first fully authenticated facultative methanotroph. It grows not only on methane and other one-carbon (C1) substrates, but also on some compounds containing carbon-carbon bonds, such as acetate, pyruvate, propane, and succinate. Here we report the full genome sequence of this bacterium.

  15. Stabilization of antimicrobial silver nanoparticles by a polyhydroxyalkanoate obtained from mixed bacterial culture.

    Science.gov (United States)

    Castro-Mayorga, J L; Martínez-Abad, A; Fabra, M J; Olivera, Catarina; Reis, M; Lagarón, J M

    2014-11-01

    The incorporation of antimicrobials into polymer matrices is a promising technology in the food packaging and biomedical areas. Among the most widely used antimicrobials, silver nanoparticles (AgNPs) have emerged as one of the most researched technologies to prevent microbial outbreaks. However, it is known that AgNPs are rather unstable and present patterns of agglomeration that might limit their application. In this work, AgNPs were produced by chemical reduction in suspensions of an unpurified poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) which was previously obtained from a mixed culture fermentation using a synthetic medium mimicking fermented cheese whey. The synthesis of AgNPs was carried out within the unpurified PHBV suspension (in situ) and by physical mixing (mix). The stability of crystalline and spherical nanoparticles (7±3nm) obtained in situ was found to be stable during at least 40 days. The results suggest that the unpurified PHBV appears to be a very efficient capping agent, preventing agglomeration and, thereby, stabilizing successfully the silver nanoparticles. The in situ obtained AgNP-PHBV materials were also found to exhibit a strong antibacterial activity against Salmonella enterica at low concentration (0.1-1ppm). Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Beyond feast and famine: Selecting a PHA accumulating photosynthetic mixed culture in a permanent feast regime.

    Science.gov (United States)

    Fradinho, J C; Reis, M A M; Oehmen, A

    2016-11-15

    Currently, the feast and famine (FF) regime is the most widely applied strategy to select for polyhydroxyalkanoate (PHA) accumulating organisms in PHA production systems with mixed microbial cultures. As an alternative to the FF regime, this work studied the possibility of utilizing a permanent feast regime as a new operational strategy to select for PHA accumulating photosynthetic mixed cultures (PMCs). The PMC was selected in an illuminated environment and acetate was constantly present in the mixed liquor to guarantee a feast regime. During steady-state operation, the culture presented low PHA accumulation levels, likely due to low light availability, which resulted in most of the acetate being used for biomass growth (Y x/s of 0.64 ± 0.18 Cmol X/Cmol Acet). To confirm the light limitation on the PMC, SBR tests were conducted with higher light availability, at similar levels as would be expectable from natural sunlight. In this case, the Y x/s reduced to 0.11 ± 0.01 Cmol X/Cmol Acet and the culture presented a PHB production yield on acetate of 0.67 ± 0.01 Cmol PHB/Cmol Acet, leading to a maximum PHB content of 60%. Unlike other studied PMCs, the PMC was capable of simultaneous growth and PHB accumulation continuously throughout the cycle. Thus far, 60% PHA content is the maximum value ever reported for a PMC, a result that prospects the utilization of feast regimes as an alternative strategy for the selection of PHA accumulating PMCs. Furthermore, the PMC also presented high phosphate removal rates, delivering an effluent that complies with phosphate discharge limits. The advantages of selecting PMCs under a permanent feast regime are that no aeration inputs are required; it allows higher PHA contents and phosphate removal rates in comparison to FF-operated PMC systems; and it represents a novel means of integrating wastewater treatment with resource recovery in the form of PHA. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. The impact of oxygen on the final alcohol content of wine fermented by a mixed starter culture.

    Science.gov (United States)

    Morales, Pilar; Rojas, Virginia; Quirós, Manuel; Gonzalez, Ramon

    2015-05-01

    We have developed a wine fermentation procedure that takes advantage of the metabolic features of a previously characterized Metschnikowia pulcherrima strain in order to reduce ethanol production. It involves the use of M. pulcherrima/Saccharomyces cerevisiae mixed cultures, controlled oxygenation conditions during the first 48 h of fermentation, and anaerobic conditions thereafter. The influence of different oxygenation regimes and initial inoculum composition on yeast physiology and final ethanol content was studied. The impact of oxygenation on yeast physiology goes beyond the first aerated step and influences yields and survival rates during the anaerobic stage. The activity of M. pulcherrima in mixed oxygenated cultures resulted in a clear reduction in ethanol yield, as compared to S. cerevisiae. Despite relatively low initial cell numbers, S. cerevisiae always predominated in mixed cultures by the end of the fermentation process. Strain replacement was faster under low oxygenation levels. M. pulcherrima confers an additional advantage in terms of dissolved oxygen, which drops to zero after a few hours of culture, even under highly aerated conditions, and this holds true for mixed cultures. Alcohol reduction values about 3.7 % (v/v) were obtained for mixed cultures under high aeration, but they were associated to unacceptable volatile acidity levels. In contrast, under optimized conditions, only 0.35 g/L acetic acid was produced, for an alcohol reduction of 2.2 % (v/v), and almost null dissolved oxygen during the process.

  18. Lipid production by pure and mixed cultures of Chlorella pyrenoidosa and Rhodotorula mucilaginosa isolated in Nuevo Leon, Mexico.

    Science.gov (United States)

    Reyna-Martínez, Raúl; Gomez-Flores, Ricardo; López-Chuken, Ulrico J; González-González, Rosario; Fernández-Delgadillo, Sergio; Balderas-Rentería, Isaias

    2015-01-01

    Given the well-known environmental drawbacks of using fossil fuels, advances in the field of alternative energy have become a worldwide technological priority. Special interest has been focused on the production of biodiesel obtained from oleaginous microorganisms. In the present research, lipid production by two species, microalgae Chlorella pyrenoidosa and yeast Rhodotorula mucilaginosa was assessed, independently and in mixed culture to evaluate a possible synergy. Fatty acid analysis was performed by gas chromatography. Among pure and mixed cultures of both strains and several culturing conditions, the highest biomass and lipid productivity was obtained by C. pyrenoidosa (8.05 and 1.62 g/L, respectively). The results of this study showed that both strains used are in fact oleaginous strains as they were found to reach up to 20 % of lipids, in addition, lipids in both pure and mixed cultures were mainly of triglycerides (>90 %), composed of fatty acid chains between 16 and 18 carbons.

  19. CHROMIUM(VI REDUCTION BY A MIXED CULTURE OF SULFATE REDUCING BACTERIA DEVELOPED IN COLUMN REACTOR

    Directory of Open Access Journals (Sweden)

    Cynthia Henny

    2008-03-01

    Full Text Available A lactate enriched mixed sulfate reducing bacteria (SRB culture was examined for the reduction of Cr(VI in a continuous flow system. The influent was mineral salts media added with lactate and sulfate with amounts of 8 and 6 mM respectively as electron donor and electron acceptor. The SRB culture was allowed to stabilize in the column before adding the Cr(VI to the influent. Chromium and sulfate reduction and lactate oxidation were examined by measuring the concentrations of Cr(Vl, sulfate and lactate in the influent and the effluent over time. The experiment was discontinued when Cr(VI concentration in the effiuent was breakthrough. In the absence of Cr(VI, sulfate was not completely reduced in the column, although lactate was completely oxidized and acetate as an intermediate product was not often detected. Almost all of Cr(VI loaded was reduced in the column seeded with the SRB culture at influent Cr(VI concentrations of 192,385 and769 mM. There was no significant Cr(VI loss in the control column, indicating that Cr(VI removal was due to the reduction of Cr(VI to Cr (lll by the SRB culture. The instantaneous Cr(VI removal decreased to a minimum of 32%, 24 days after the influent Cr(VI concentration was increased to 1540 mM, ancl sulfate removal efficiency decreased to a minimum of 17%. The SRB population in the column decreased 100 days after C(VI was added to the column. The total mass of Cr(VI reduced was approximately 878 mmol out of 881 mmol of Cr(Vl loaded in 116 days. The results clearly show that our developed SRB culture could reduced Cr(Vl considerably.

  20. How guiding coalitions promote positive culture change in hospitals: a longitudinal mixed methods interventional study.

    Science.gov (United States)

    Bradley, Elizabeth H; Brewster, Amanda L; McNatt, Zahirah; Linnander, Erika L; Cherlin, Emily; Fosburgh, Heather; Ting, Henry H; Curry, Leslie A

    2018-03-01

    Quality collaboratives are widely endorsed as a potentially effective method for translating and spreading best practices for acute myocardial infarction (AMI) care. Nevertheless, hospital success in improving performance through participation in collaboratives varies markedly. We sought to understand what distinguished hospitals that succeeded in shifting culture and reducing 30-day risk-standardised mortality rate (RSMR) after AMI through their participation in the Leadership Saves Lives (LSL) collaborative. We conducted a longitudinal, mixed methods intervention study of 10 hospitals over a 2-year period; data included surveys of 223 individuals (response rates 83%-94% depending on wave) and 393 in-depth interviews with clinical and management staff most engaged with the LSL intervention in the 10 hospitals. We measured change in culture and RSMR, and key aspects of working related to team membership, turnover, level of participation and approaches to conflict management. The six hospitals that experienced substantial culture change and greater reductions in RSMR demonstrated distinctions in: (1) effective inclusion of staff from different disciplines and levels in the organisational hierarchy in the team guiding improvement efforts (referred to as the 'guiding coalition' in each hospital); (2) authentic participation in the work of the guiding coalition; and (3) distinct patterns of managing conflict. Guiding coalition size and turnover were not associated with success (p values>0.05). In the six hospitals that experienced substantial positive culture change, staff indicated that the LSL learnings were already being applied to other improvement efforts. Hospitals that were most successful in a national quality collaborative to shift hospital culture and reduce RSMR showed distinct patterns in membership diversity, authentic participation and capacity for conflict management. © Article author(s) (or their employer(s) unless otherwise stated in the text of the

  1. Comparison of an ability to degrade MTBE between mixed culture and monoculture isolated from gasoline contaminated soil

    Directory of Open Access Journals (Sweden)

    Wanpen Virojanakud

    2004-02-01

    Full Text Available Methyl tertiary butyl ether (MTBE is an oxygenated compound used to enhance the octane index of gasoline and replace lead in gasoline. MTBE can reduce air pollution but causes water pollution due to its high water solubility and low sorption to soil and thus can easily contaminate the environment. Biodegradation is one of the promising techniques to reduce MTBE contaminated in the environment and MTBE degrader was proposed as an efficient method used to degrade MTBE. In this study, MTBE degraders were isolated from gasoline contaminated soil and then were evaluated with the hypothesis that MTBE degraders could improve biodegradation of MTBE in soil and mixed culture could degrade MTBE more rapidly than monoculture. Gasoline contaminated soil samples were taken from retail gas stations and a motorcycle repair shop in Khon Kaen University. Isolation of MTBE degrader was conducted by using Basal Salt Medium (BSM containing 200 mg/L of MTBE as a carbon source. Mixed culture of MTBE degrader was successfully isolated under aerobic condition. Morphology study was conducted by streaking isolated mixed culture in solid medium, agar slant and identifying the cells shape under a microscope. It was found that this mixed culture was a gram negative bacteria with 7 different isolates. A comparison of the ability to degrade MTBE between mixed culture and monoculture was investigated in BSM containing 100 mg/L of MTBE. The results indicated that a mixed culture degraded MTBE more rapidly than monoculture i.e. 20% within 14 days. Monoculture, J4 and J7, were the most rapid MTBE degraders among the other monocultures in which they degraded 14% of MTBE in 14 days while monoculture J15 could degrade only 1% of MTBE.This preliminary result suggests that mixed cultures degrade MTBE more efficiently than monoculture.

  2. Methanotrophic bacteria in warm geothermal spring sediments identified using stable-isotope probing.

    Science.gov (United States)

    Sharp, Christine E; Martínez-Lorenzo, Azucena; Brady, Allyson L; Grasby, Stephen E; Dunfield, Peter F

    2014-10-01

    We investigated methanotrophic bacteria in sediments of several warm geothermal springs ranging in temperature from 22 to 45 °C. Methane oxidation was measured at potential rates up to 141 μmol CH4 d(-1) g(-1) sediment. Active methanotrophs were identified using (13) CH4 stable-isotope probing (SIP) incubations performed at close to in situ temperatures for each site. Quantitative (q) PCR of pmoA genes identified the position of the heavy ((13) C-labelled) DNA fractions in density gradients, and 16S rRNA gene pyrotag sequencing of the heavy fractions was performed to identify the active methanotrophs. Methanotroph communities identified in heavy fractions of all samples were predominated by species similar (≥ 95% 16S rRNA gene identities) to previously characterized Gammaproteobacteria and Alphaproteobacteria methanotrophs. Among the five hottest samples (45 °C), members of the Gammaproteobacteria genus Methylocaldum dominated in two cases, while three others were dominated by an OTU closely related (96.8% similarity) to the Alphaproteobacteria genus Methylocapsa. These results suggest that diverse methanotroph groups are adapted to warm environments, including the Methylocapsa-Methylocella-Methyloferula group, which has previously only been detected in cooler sites. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  3. Identity of active methanotrophs in landfill cover soil as revealed by DNA-stable isotope probing.

    Science.gov (United States)

    Cébron, Aurélie; Bodrossy, Levente; Chen, Yin; Singer, Andrew C; Thompson, Ian P; Prosser, James I; Murrell, J Colin

    2007-10-01

    A considerable amount of methane produced during decomposition of landfill waste can be oxidized in landfill cover soil by methane-oxidizing bacteria (methanotrophs) thus reducing greenhouse gas emissions to the atmosphere. The identity of active methanotrophs in Roscommon landfill cover soil, a slightly acidic peat soil, was assessed by DNA-stable isotope probing (SIP). Landfill cover soil slurries were incubated with (13)C-labelled methane and under either nutrient-rich nitrate mineral salt medium or water. The identity of active methanotrophs was revealed by analysis of (13)C-labelled DNA fractions. The diversity of functional genes (pmoA and mmoX) and 16S rRNA genes was analyzed using clone libraries, microarrays and denaturing gradient gel electrophoresis. 16S rRNA gene analysis revealed that the cover soil was mainly dominated by Type II methanotrophs closely related to the genera Methylocella and Methylocapsa and to Methylocystis species. These results were supported by analysis of mmoX genes in (13)C-DNA. Analysis of pmoA gene diversity indicated that a significant proportion of active bacteria were also closely related to the Type I methanotrophs, Methylobacter and Methylomonas species. Environmental conditions in the slightly acidic peat soil from Roscommon landfill cover allow establishment of both Type I and Type II methanotrophs.

  4. Active methanotrophs in two contrasting North American peatland ecosystems revealed using DNA-SIP.

    Science.gov (United States)

    Gupta, Varun; Smemo, Kurt A; Yavitt, Joseph B; Basiliko, Nathan

    2012-02-01

    The active methanotroph community was investigated in two contrasting North American peatlands, a nutrient-rich sedge fen and nutrient-poor Sphagnum bog using in vitro incubations and (13)C-DNA stable-isotope probing (SIP) to measure methane (CH(4)) oxidation rates and label active microbes followed by fingerprinting and sequencing of bacterial and archaeal 16S rDNA and methane monooxygenase (pmoA and mmoX) genes. Rates of CH(4) oxidation were slightly, but significantly, faster in the bog and methanotrophs belonged to the class Alphaproteobacteria and were similar to other methanotrophs of the genera Methylocystis, Methylosinus, and Methylocapsa or Methylocella detected in, or isolated from, European bogs. The fen had a greater phylogenetic diversity of organisms that had assimilated (13)C, including methanotrophs from both the Alpha- and Gammaproteobacteria classes and other potentially non-methanotrophic organisms that were similar to bacteria detected in a UK and Finnish fen. Based on similarities between bacteria in our sites and those in Europe, including Russia, we conclude that site physicochemical characteristics rather than biogeography controlled the phylogenetic diversity of active methanotrophs and that differences in phylogenetic diversity between the bog and fen did not relate to measured CH(4) oxidation rates. A single crenarchaeon in the bog site appeared to be assimilating (13)C in 16S rDNA; however, its phylogenetic similarity to other CO(2)-utilizing archaea probably indicates that this organism is not directly involved in CH(4) oxidation in peat.

  5. Tackling Carbon Emission with Nature: Effectiveness of Indigenous Microalgae Mixed Culture

    Directory of Open Access Journals (Sweden)

    Chik M. Nazry

    2016-01-01

    Full Text Available Marine microalgae species was isolated and identified from its native condition of sea water discharge canals at the TNB Janamanjung Sdn Bhd’s coal-fired power station. The species was expected to be a robust one based on the prevalent harsh upstream conditions and processes the survived ones endured. The isolation involves streaking-plating method as well as serial dilution and liquid media culture propagation. Morphological and molecular identification were both carried out before satisfactory identification of Chlorella sp. be made. This species was later mixed with marine Isochrysis sp. with varying volumetric proportions and cultured in five separate air-lift bubbling column photobioreactors, as part of the experiment to determine which optimum volumetric culture ratio is best to fix CO2 from the power plant. Results indicate that a more dominant ratio of Chlorella sp. 75% and Isochrysis sp. 25% by volume provide gives a better growth profile and indicates a better CO2 fixation rates.

  6. Assessing the Efficacy of the Aerobic Methanotrophic Biofilter in Methane Hydrate Environments

    Energy Technology Data Exchange (ETDEWEB)

    Valentine, David

    2012-09-30

    In October 2008 the University of California at Santa Barbara (UCSB) initiated investigations of water column methane oxidation in methane hydrate environments, through a project funded by the National Energy Technology Laboratory (NETL) entitled: assessing the efficacy of the aerobic methanotrophic biofilter in methane hydrate environments. This Final Report describes the scientific advances and discoveries made under this award as well as the importance of these discoveries in the broader context of the research area. Benthic microbial mats inhabit the sea floor in areas where reduced chemicals such as sulfide reach the more oxidizing water that overlies the sediment. We set out to investigate the role that methanotrophs play in such mats at locations where methane reaches the sea floor along with sulfide. Mats were sampled from several seep environments and multiple sets were grown in-situ at a hydrocarbon seep in the Santa Barbara Basin. Mats grown in-situ were returned to the laboratory and used to perform stable isotope probing experiments in which they were treated with 13C-enriched methane. The microbial community was analyzed, demonstrating that three or more microbial groups became enriched in methane?s carbon: methanotrophs that presumably utilize methane directly, methylotrophs that presumably consume methanol excreted by the methanotrophs, and sulfide oxidizers that presumably consume carbon dioxide released by the methanotrophs and methylotrophs. Methanotrophs reached high relative abundance in mats grown on methane, but other bacterial processes include sulfide oxidation appeared to dominate mats, indicating that methanotrophy is not a dominant process in sustaining these benthic mats, but rather a secondary function modulated by methane availability. Methane that escapes the sediment in the deep ocean typically dissolved into the overlying water where it is available to methanotrophic bacteria. We set out to better understand the efficacy of this

  7. Ammonia Oxidation and Nitrite Reduction in the Verrucomicrobial Methanotroph Methylacidiphilum fumariolicum SolV

    Directory of Open Access Journals (Sweden)

    Sepehr S. Mohammadi

    2017-09-01

    Full Text Available The Solfatara volcano near Naples (Italy, the origin of the recently discovered verrucomicrobial methanotroph Methylacidiphilum fumariolicum SolV was shown to contain ammonium (NH4+ at concentrations ranging from 1 to 28 mM. Ammonia (NH3 can be converted to toxic hydroxylamine (NH2OH by the particulate methane monooxygenase (pMMO, the first enzyme of the methane (CH4 oxidation pathway. Methanotrophs rapidly detoxify the intermediate NH2OH. Here, we show that strain SolV performs ammonium oxidation to nitrite at a rate of 48.2 nmol NO2-.h−1.mg DW−1 under O2 limitation in a continuous culture grown on hydrogen (H2 as an electron donor. In addition, strain SolV carries out nitrite reduction at a rate of 74.4 nmol NO2-.h−1.mg DW−1 under anoxic condition at pH 5–6. This range of pH was selected to minimize the chemical conversion of nitrite (NO2- potentially occurring at more acidic pH values. Furthermore, at pH 6, we showed that the affinity constants (Ks of the cells for NH3 vary from 5 to 270 μM in the batch incubations with 0.5–8% (v/v CH4, respectively. Detailed kinetic analysis showed competitive substrate inhibition between CH4 and NH3. Using transcriptome analysis, we showed up-regulation of the gene encoding hydroxylamine dehydrogenase (haoA cells grown on H2/NH4+ compared to the cells grown on CH4/NO3- which do not have to cope with reactive N-compounds. The denitrifying genes nirk and norC showed high expression in H2/NH4+ and CH4/NO3- grown cells compared to cells growing at μmax (with no limitation while the norB gene showed downregulation in CH4/NO3- grown cells. These cells showed a strong upregulation of the genes in nitrate/nitrite assimilation. Our results demonstrate that strain SolV can perform ammonium oxidation producing nitrite. At high concentrations of ammonium this may results in toxic effects. However, at low oxygen concentrations strain SolV is able to reduce nitrite to N2O to cope with this toxicity.

  8. A novel methanotroph in the genus Methylomonas that contains a distinct clade of soluble methane monooxygenase.

    Science.gov (United States)

    Nguyen, Ngoc-Loi; Yu, Woon-Jong; Yang, Hye-Young; Kim, Jong-Geol; Jung, Man-Young; Park, Soo-Je; Roh, Seong-Woon; Rhee, Sung-Keun

    2017-10-01

    Aerobic methane oxidation is a key process in the global carbon cycle that acts as a major sink of methane. In this study, we describe a novel methanotroph designated EMGL16-1 that was isolated from a freshwater lake using the floating filter culture technique. Based on a phylogenetic analysis of 16S rRNA gene sequences, the isolate was found to be closely related to the genus Methylomonas in the family Methylococcaceae of the class Gammaproteobacteria with 94.2-97.4% 16S rRNA gene similarity to Methylomonas type strains. Comparison of chemotaxonomic and physiological properties further suggested that strain EMGL16-1 was taxonomically distinct from other species in the genus Methylomonas. The isolate was versatile in utilizing nitrogen sources such as molecular nitrogen, nitrate, nitrite, urea, and ammonium. The genes coding for subunit of the particulate form methane monooxygenase (pmoA), soluble methane monooxygenase (mmoX), and methanol dehydrogenase (mxaF) were detected in strain EMGL16-1. Phylogenetic analysis of mmoX indicated that mmoX of strain EMGL16-1 is distinct from those of other strains in the genus Methylomonas. This isolate probably represents a novel species in the genus. Our study provides new insights into the diversity of species in the genus Methylomonas and their environmental adaptations.

  9. The binning of metagenomic contigs for microbial physiology of mixed cultures.

    Science.gov (United States)

    Strous, Marc; Kraft, Beate; Bisdorf, Regina; Tegetmeyer, Halina E

    2012-01-01

    So far, microbial physiology has dedicated itself mainly to pure cultures. In nature, cross feeding and competition are important aspects of microbial physiology and these can only be addressed by studying complete communities such as enrichment cultures. Metagenomic sequencing is a powerful tool to characterize such mixed cultures. In the analysis of metagenomic data, well established algorithms exist for the assembly of short reads into contigs and for the annotation of predicted genes. However, the binning of the assembled contigs or unassembled reads is still a major bottleneck and required to understand how the overall metabolism is partitioned over different community members. Binning consists of the clustering of contigs or reads that apparently originate from the same source population. In the present study eight metagenomic samples from the same habitat, a laboratory enrichment culture, were sequenced. Each sample contained 13-23 Mb of assembled contigs and up to eight abundant populations. Binning was attempted with existing methods but they were found to produce poor results, were slow, dependent on non-standard platforms or produced errors. A new binning procedure was developed based on multivariate statistics of tetranucleotide frequencies combined with the use of interpolated Markov models. Its performance was evaluated by comparison of the results between samples with BLAST and in comparison to existing algorithms for four publicly available metagenomes and one previously published artificial metagenome. The accuracy of the new approach was comparable or higher than existing methods. Further, it was up to a 100 times faster. It was implemented in Java Swing as a complete open source graphical binning application available for download and further development (http://sourceforge.net/projects/metawatt).

  10. The binning of metagenomic contigs for microbial physiology of mixed cultures

    Directory of Open Access Journals (Sweden)

    Marc eStrous

    2012-12-01

    Full Text Available So far, microbial physiology has dedicated itself mainly to pure cultures. In nature, cross feeding and competition are important aspects of microbial physiology and these can only be addressed by studying complete communities such as enrichment cultures. Metagenomic sequencing is a powerful tool to characterize such mixed cultures. In the analysis of metagenomic data, well established algorithms exist for the assembly of short reads into contigs and for the annotation of predicted genes. However, the binning of the assembled contigs or unassembled reads is still a major bottleneck and required to understand how the overall metabolism is partitioned over different community members. Binning consists of the clustering of contigs or reads that apparently originate from the same source population.In the present study eight metagenomic samples originating from the same habitat, a laboratory enrichment culture, were sequenced. Each sample contained 13-23 Mb of assembled contigs and up to eight abundant populations. Binning was attempted with existing methods but they were found to produce poor results, were slow, dependent on non-standard platforms or produced errors. A new binning procedure was developed based on multivariate statistics of tetranucleotide frequencies combined with the use of interpolated Markov models. Its performance was evaluated by comparison of the results between samples with BLAST and in comparison to exisiting algorithms for four publicly available metagenomes and one previously published artificial metagenome. The accuracy of the new approach was comparable or higher than existing methods. Further, it was up to a hunderd times faster. It was implemented in Java Swing as a complete open source graphical binning application available for download and further development (http://sourceforge.net/projects/metawatt.

  11. Evaluation of in-situ methanotrophic bioremediation for contaminated groundwater, St. Joseph, Michigan. Final report, January 1989-December 1989

    International Nuclear Information System (INIS)

    McCarty, P.L.; Semprini, L.; Dolan, M.E.; Harmon, T.C.; Just, S.

    1990-09-01

    A feasibility study of utilizing indigenous bacteria that use methane as a source of cell carbon and energy (methanotrophs) for in-situ bioremediation of groundwater contaminants at the St. Joseph site is summarized. The contaminants, compounds, can be biotransformed by methanotrophic bacteria, which are found in some locations of the site in adequate populations. The process involves stimulating the growth of native populations of methanotrophs by injecting water containing dissolved methane and oxygen into the aquifer. The stimulated population of methanotrophs in turn has the capability to degrade trichloroethylene, 1,2-cis-dichloroethylene, 1,2-trans-dichloroethylene, and vinyl chloride

  12. Effect of nutrient and selective inhibitor amendments on methane oxidation, nitrous oxide production, and key gene presence and expression in landfill cover soils: characterization of the role of methanotrophs, nitrifiers, and denitrifiers.

    Science.gov (United States)

    Lee, Sung-Woo; Im, Jeongdae; Dispirito, Alan A; Bodrossy, Levente; Barcelona, Michael J; Semrau, Jeremy D

    2009-11-01

    Methane and nitrous oxide are both potent greenhouse gasses, with global warming potentials approximately 25 and 298 times that of carbon dioxide. A matrix of soil microcosms was constructed with landfill cover soils collected from the King Highway Landfill in Kalamazoo, Michigan and exposed to geochemical parameters known to affect methane consumption by methanotrophs while also examining their impact on biogenic nitrous oxide production. It was found that relatively dry soils (5% moisture content) along with 15 mg NH (4) (+) (kg soil)(-1) and 0.1 mg phenylacetylene(kg soil)(-1) provided the greatest stimulation of methane oxidation while minimizing nitrous oxide production. Microarray analyses of pmoA showed that the methanotrophic community structure was dominated by Type II organisms, but Type I genera were more evident with the addition of ammonia. When phenylacetylene was added in conjunction with ammonia, the methanotrophic community structure was more similar to that observed in the presence of no amendments. PCR analyses showed the presence of amoA from both ammonia-oxidizing bacteria and archaea, and that the presence of key genes associated with these cells was reduced with the addition of phenylacetylene. Messenger RNA analyses found transcripts of pmoA, but not of mmoX, nirK, norB, or amoA from either ammonia-oxidizing bacteria or archaea. Pure culture analyses showed that methanotrophs could produce significant amounts of nitrous oxide, particularly when expressing the particulate methane monooxygenase (pMMO). Collectively, these data suggest that methanotrophs expressing pMMO played a role in nitrous oxide production in these microcosms.

  13. Use of whey lactose from dairy industry for economical kefiran production by Lactobacillus kefiranofaciens in mixed cultures with yeasts.

    Science.gov (United States)

    Cheirsilp, Benjamas; Radchabut, Sirilaor

    2011-10-01

    To evaluate the feasibility of producing kefiran industrially, whey lactose, a by-product from dairy industry, was used as a low cost carbon source. Because the accumulation of lactic acid as a by-product of Lactobacillus kefiranofaciens inhibited cell growth and kefiran production, the kefir grain derived and non-derived yeasts were screened for their abilities to reduce lactic acid and promote kefiran production in a mixed culture. Six species of yeasts were examined: Torulaspora delbrueckii IFO 1626; Saccharomyces cerevisiae IFO 0216; Debaryomyces hansenii TISTR 5155; Saccharomyces exiguus TISTR 5081; Zygosaccharomyces rouxii TISTR 5044; and Saccharomyces carlsbergensis TISTR 5018. The mixed culture of L. kefiranofaciens with S. cerevisiae IFO 0216 enhanced the kefiran production best from 568 mg/L in the pure culture up to 807 and 938 mg/L in the mixed cultures under anaerobic and microaerobic conditions, respectively. The optimal conditions for kefiran production by the mixed culture were: whey lactose 4%; yeast extract 4%; initial pH of 5.5; and initial amounts of L. kefiranofaciens and S. cerevisiae IFO 0216 of 2.1×10(7) and 4.0×10(6)CFU/mL, respectively. Scaling up the mixed culture in a 2L bioreactor with dissolved oxygen control at 5% and pH control at 5.5 gave the maximum kefiran production of 2,580 mg/L in batch culture and 3,250 mg/L in fed-batch culture. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Nonspecific suppressor T cells cause decreased mixed lymphocyte culture reactivity in bone marrow transplant patients

    International Nuclear Information System (INIS)

    Harada, M.; Ueda, M.; Nakao, S.; Kondo, K.; Odaka, K.; Shiobara, S.; Matsue, K.; Mori, T.; Matsuda, T.

    1986-01-01

    Decreased reactivity in mixed lymphocyte culture (MLC) was observed in patients within 1 yr after allogeneic and autologous bone marrow transplantation. Suppressor activity of peripheral blood mononuclear cells (PBMC) from transplant patients was studied by adding these cells as modulator cells to a bidirectional MLC with cells from normal individuals. PBMC from transplant patients markedly suppressed MLC reactivity in a dose-dependent manner. Suppressor activity was present in cells forming rosettes with sheep erythrocytes. Treatment of modulator cells with monoclonal antibodies against T cell differentiation antigens (OKT8, OKIa1) and complement completely abolished suppression of MLC. Suppressor activity was unaffected by 30 Gy irradiation. Suppressor activity declined gradually after transplantation and was inversely correlated with MLC reactivity of each patient at a significant level (p less than 0.01). These observations suggest that OKT8+ Ia+ radioresistant suppressor T cells play a role in the development of decreased MLC reactivity observed during the early post-transplant period

  15. Saccharomyces cerevisiae mixed culture of blackberry (Rubus ulmifolius L.) juice: synergism in the aroma compounds production.

    Science.gov (United States)

    Bautista-Rosales, Pedro Ulises; Ragazzo-Sánchez, Juan Arturo; Ruiz-Montañez, Gabriela; Ortiz-Basurto, Rosa Isela; Luna-Solano, Guadalupe; Calderón-Santoyo, Montserrat

    2014-01-01

    Blackberry (Rubus sp.) juice was fermented using four different strains of Saccharomyces cerevisiae (Vitilevure-CM4457, Enoferm-T306, ICV-K1, and Greroche Rhona-L3574) recognized because of their use in the wine industry. A medium alcoholic graduation spirit (industrial scale was obtained. Alcoholic fermentations were performed at 28°C, 200 rpm, and noncontrolled pH. The synergistic effect on the aromatic compounds production during fermentation in mixed culture was compared with those obtained by monoculture and physic mixture of spirits produced in monoculture. The aromatic composition was determined by HS-SPME-GC. The differences in aromatic profile principally rely on the proportions in aromatic compounds and not on the number of those compounds. The multivariance analysis, principal component analysis (PCA), and factorial discriminant analysis (DFA) permit to demonstrate the synergism between the strains.

  16. Waste to bioproduct conversion with undefined mixed cultures: the carboxylate platform.

    Science.gov (United States)

    Agler, Matthew T; Wrenn, Brian A; Zinder, Stephen H; Angenent, Largus T

    2011-02-01

    Our societies generate increasing volumes of organic wastes. Considering that we also need alternatives to oil, an opportunity exists to extract liquid fuels or even industrial solvents from these abundant wastes. Anaerobic undefined mixed cultures can handle the complexity and variability of organic wastes, which produces carboxylates that can be efficiently converted to useful bioproducts. However, to date, barriers, such as inefficient liquid product separation and persistence of methanogens, have prevented the production of bioproducts other than methane. Here, we discuss combinations of biological and chemical pathways that comprise the 'carboxylate platform', which is used to convert waste to bioproducts. To develop the carboxylate platform into an important system within biorefineries, we must understand the kinetic and thermodynamic possibilities of anaerobic pathways, understand the ecological principles underlying pathway alternatives, and develop superior separation technologies. Copyright © 2010 Elsevier Ltd. All rights reserved.

  17. Butyric acid fermentation of sodium hydroxide pretreated rice straw with undefined mixed culture.

    Science.gov (United States)

    Ai, Binling; Li, Jianzheng; Chi, Xue; Meng, Jia; Liu, Chong; Shi, En

    2014-05-01

    This study describes an alternative mixed culture fermentation technology to anaerobically convert lignocellulosic biomass into butyric acid, a valuable product with wide application, without supplementary cellulolytic enzymes. Rice straw was soaked in 1% NaOH solution to increase digestibility. Among the tested pretreatment conditions, soaking rice straw at 50°C for 72 h removed ~66% of the lignin, but retained ~84% of the cellulose and ~71% of the hemicellulose. By using an undefined cellulose-degrading butyrate-producing microbial community as butyric acid producer in batch fermentation, about 6 g/l of butyric acid was produced from the pretreated rice straw, which accounted for ~76% of the total volatile fatty acids. In the repeated-batch operation, the butyric acid production declined batch by batch, which was most possibly caused by the shift of microbial community structure monitored by denaturing gradient gel electrophoresis. In this study, batch operation was observed to be more suitable for butyric acid production.

  18. Critical assessment of extracellular polymeric substances extraction methods from mixed culture biomass

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Domingo Felez, Carlos; Mutlu, Ayten Gizem

    2013-01-01

    . This study presents a rigorous and critical assessment of existing physical and chemical EPS extraction methods applied to mixed-culture biomass samples (nitrifying, nitritation-anammox, and activated sludge biomass). A novel fluorescence-based method was developed and calibrated to quantify the lysis...... potential of different EPS extraction protocols. We concluded that commonly used methods to assess cell lysis (DNA concentrations or G6PDH activities in EPS extracts) do not correlate with cell viability. Furthermore, we discovered that the presence of certain chemicals in EPS extracts results in severe...... underestimation of protein and carbohydrate concentrations by using standard analytical methods. Keeping both maximum EPS extraction yields and minimal biomass lysis as criteria, it was identified a sonication-based extraction method as the best to determine and compare tightly-bound EPS fractions in different...

  19. Saccharomyces cerevisiae Mixed Culture of Blackberry (Rubus ulmifolius L. Juice: Synergism in the Aroma Compounds Production

    Directory of Open Access Journals (Sweden)

    Pedro Ulises Bautista-Rosales

    2014-01-01

    Full Text Available Blackberry (Rubus sp. juice was fermented using four different strains of Saccharomyces cerevisiae (Vitilevure-CM4457, Enoferm-T306, ICV-K1, and Greroche Rhona-L3574 recognized because of their use in the wine industry. A medium alcoholic graduation spirit (<6GL° with potential to be produced at an industrial scale was obtained. Alcoholic fermentations were performed at 28C°, 200 rpm, and noncontrolled pH. The synergistic effect on the aromatic compounds production during fermentation in mixed culture was compared with those obtained by monoculture and physic mixture of spirits produced in monoculture. The aromatic composition was determined by HS-SPME-GC. The differences in aromatic profile principally rely on the proportions in aromatic compounds and not on the number of those compounds. The multivariance analysis, principal component analysis (PCA, and factorial discriminant analysis (DFA permit to demonstrate the synergism between the strains.

  20. Biodegradability of carbon nanotube/polymer nanocomposites under aerobic mixed culture conditions.

    Science.gov (United States)

    Phan, Duc C; Goodwin, David G; Frank, Benjamin P; Bouwer, Edward J; Fairbrother, D Howard

    2018-10-15

    The properties and commercial viability of biodegradable polymers can be significantly enhanced by the incorporation of carbon nanotubes (CNTs). The environmental impact and persistence of these carbon nanotube/polymer nanocomposites (CNT/PNCs) after disposal will be strongly influenced by their microbial interactions, including their biodegradation rates. At the end of consumer use, CNT/PNCs will encounter diverse communities of microorganisms in landfills, surface waters, and wastewater treatment plants. To explore CNT/PNC biodegradation under realistic environmental conditions, the effect of multi-wall CNT (MWCNT) incorporation on the biodegradation of polyhydroxyalkanoates (PHA) was investigated using a mixed culture of microorganisms from wastewater. Relative to unfilled PHA (0% w/w), the MWCNT loading (0.5-10% w/w) had no statistically significant effect on the rate of PHA matrix biodegradation. Independent of the MWCNT loading, the extent of CNT/PNC mass remaining closely corresponded to the initial mass of CNTs in the matrix suggesting a lack of CNT release. CNT/PNC biodegradation was complete in approximately 20 days and resulted in the formation of a compressed CNT mat that retained the shape of the initial CNT/PNC. This study suggests that although CNTs have been shown to be cytotoxic towards a range of different microorganisms, this does not necessarily impact the biodegradation of the surrounding polymer matrix in mixed culture, particularly in situations where the polymer type and/or microbial population favor rapid polymer biodegradation. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Coupling limonene formation and oxyfunctionalization by mixed-culture resting cell fermentation.

    Science.gov (United States)

    Willrodt, Christian; Hoschek, Anna; Bühler, Bruno; Schmid, Andreas; Julsing, Mattijs K

    2015-09-01

    Metabolic engineering strategies mark a milestone for the fermentative production of bulk and fine chemicals. Yet, toxic products and volatile reaction intermediates with low solubilities remain challenging. Prominent examples are artificial multistep pathways like the production of perillyl acetate (POHAc) from glucose via limonene. For POHAc, these limitations can be overcome by mixed-culture fermentations. A limonene biosynthesis pathway and cytochrome P450 153A6 (CYP153A6) as regioselective hydroxylase are used in two distinct recombinant E. coli. POHAc formation from glucose in one recombinant cell was hindered by ineffective coupling of limonene synthesis and low rates of oxyfunctionalization. The optimization of P450 gene expression led to the formation of 6.20 ± 0.06 mg gcdw (-1) POHAc in a biphasic batch cultivation with glucose as sole carbon and energy source. Increasing the spatial proximity between limonene synthase and CYP153A6 by a genetic fusion of both enzymes changed the molar limonene/POHAc ratio from 3.2 to 1.6. Spatial separation of limonene biosynthesis from its oxyfunctionalization improved POHAc concentration 3.3-fold to 21.7 mg L(-1) as compared to a biphasic fermentation. Mixed-cultures of E. coli BL21 (DE3) containing the limonene biosynthesis pathway and E. coli MG1655 harboring either CYP153A6, or alternatively a cymene monooxygenase, showed POHAc formation rates of 0.06 or 0.11 U gcdw (-1) , respectively. This concept provides a novel framework for fermentative syntheses involving toxic, volatile, or barely soluble compounds or pathway intermediates. © 2015 Wiley Periodicals, Inc.

  2. Hydrogen production from rice winery wastewater in an upflow anaerobic reactor by using mixed anaerobic cultures

    Energy Technology Data Exchange (ETDEWEB)

    Hanqing Yu; Zhenhu Zhu [University of Science and Technology, Hefei, Anhui (China). School of Chemistry and Materials; Wenrong Hu [Shandong Univ., Jinan (China). School of Resources and Environmental Engineering; Haisheng Zhang [Jingzi Wine Distillery Company, Shandong (China)

    2002-12-01

    Continuous production of hydrogen from the anaerobic acidogenesis of a high-strength rice winery wastewater by a mixed bacterial flora was demonstrated. The experiment was conducted in a 3.0-l upflow reactor to investigate individual effects of hydraulic retention time (HRT) (2-24 h), chemical oxygen demand (COD) concentration in wastewater (14-36 g COD/l), pH (4.5-6.0) and temperature (20-55{sup o}C) on bio-hydrogen production from the wastewater. The biogas produced under all test conditions was composed of mostly hydrogen (53-61%) and carbon dioxide (37-45%), but contained no detectable methane. Specific hydrogen production rate increased with wastewater concentration and temperature, but with a decrease in HRT. An optimum hydrogen production rate of 9.33 lH{sub 2}/gVSSd was achieved at an HRT of 2 h, COD of 34 g/l, pH 5.5 and 55{sup o}C. The hydrogen yield was in the range of 1.37-2.14 mol/mol-hexose. In addition to acetate, propionate and butyrate, ethanol was also present in the effluent as an aqueous product. The distribution of these compounds in the effluent was more sensitive to wastewater concentration, pH and temperature, but was less sensitive to HRT. This upflow reactor was shown to be a promising biosystem for hydrogen production from high-strength wastewaters by mixed anaerobic cultures. (Author)

  3. Experimental and mathematical model of the interactions in the mixed culture of links in the “producer-consumer” cycle

    Science.gov (United States)

    Pisman, T. I.

    2009-07-01

    The paper presents a experimental and mathematical model of interactions between invertebrates (the ciliates Paramecium caudatum and the rotifers Brachionus plicatilis) in the "producer-consumer" aquatic biotic cycle with spatially separated components. The model describes the dynamics of the mixed culture of ciliates and rotifers in the "consumer" component, feeding on the mixed algal culture of the "producer" component. It has been found that metabolites of the algae Scenedesmus produce an adverse effect on the reproduction of the ciliates P. caudatum. Taking into account this effect, the results of investigation of the mathematical model were in qualitative agreement with the experimental results. In the "producer-consumer" biotic cycle it was shown that coexistence is impossible in the mixed culture of invertebrates of the "consumer" component. The ciliates P. caudatum are driven out by the rotifers B. plicatilis.

  4. Biohydrogen production from desugared molasses (DM) using thermophilic mixed cultures immobilized on heat treated anaerobic sludge granules

    DEFF Research Database (Denmark)

    Kongjan, Prawit; O-Thong, Sompong; Angelidaki, Irini

    2011-01-01

    Hydrogen production from desugared molasses (DM) was investigated in both batch and continuous reactors using thermophilic mixed cultures enriched from digested manure by load shock (loading with DM concentration of 50.1 g-sugar/L) to suppress methanogens. H2 gas, free of methane, was produced......) and Thermoanaerobacterium thermosaccharolyticum with a relative abundance of 36%, 27%, and 10% of total microorganisms, respectively. This study shows that hydrogen production could be efficiently facilitated by using anaerobic granules as a carrier, where microbes from mixed culture enriched in the DM batch cultivation....... The enriched hydrogen producing mixed culture achieved from the 16.7 g-sugars/L DM batch cultivation was immobilized on heat treated anaerobic sludge granules in an up-flow anaerobic sludge blanket (UASB) reactor. The UASB reactor, operated at a hydraulic retention time (HRT) of 24 h fed with 16.7 g...

  5. Consolidated bioprocessing for butyric acid production from rice straw with undefined mixed culture

    Directory of Open Access Journals (Sweden)

    Binling Ai

    2016-10-01

    Full Text Available Lignocellulosic biomass is a renewable source with great potential for biofuels and bioproducts. However, the cost of cellulolytic enzymes limits the utilization of the low-cost bioresource. This study aimed to develop a consolidated bioprocessing without the need of supplementary cellulase for butyric acid production from lignocellulosic biomass. A stirred-tank reactor with a working volume of 21 L was constructed and operated in batch and semi-continuous fermentation modes with a cellulolytic butyrate-producing microbial community. The semi-continuous fermentation with intermittent discharging of the culture broth and replenishment with fresh medium achieved the highest butyric acid productivity of 2.69 g/(L•d. In semi-continuous operation mode, the butyric acid and total carboxylic acid concentrations of 16.2 and 28.9 g/L, respectively, were achieved. Over the 21-day fermentation period, their cumulative yields reached 1189 and 2048 g, respectively, corresponding to 41% and 74% of the maximum theoretical yields based on the amount of NaOH pretreated rice straw fed in. This study demonstrated that an undefined mixed culture-based consolidated bioprocessing for butyric acid production can completely eliminate the cost of supplementary cellulolytic enzymes.

  6. Enhanced biodegradation of Pina Cuban crude oil by a culture of mixed marine bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, I.N.; Perigo, E. [Ministry of Science. Inst. of Oceanography, La Habana (Cuba); Bergueiro, J.R.; Pita, A.; Mayol, M.A. [Balearic Island Univ., Palma de Mallorca, Islas Baleares (Spain); Navarro, A. [Ministry of Industry, Oil Research Center, La Habana (Cuba)

    1998-09-01

    The ability of a mixed marine bacteria culture to degrade Pina Cuban crude oil in the presence of nutrients and sea water was studied. Laboratory experiments were conducted in flasks with 100 ml of saline liquid containing 1 per cent crude. The flasks were inoculated with marine bacteria (IDO-225, IDO-226, and IDO-229) at a final concentration of 10{sup 6} cell/ml. The cultures were grown at 29 degrees C for 21 days. Bacterial growth, and surface and interfacial tension were measured after 5, 13 and 21 days. Results showed that the marine bacteria were effective in accelerating the biodegradation process of Pina Cuban oil. The efficiency of the process increased when nutrients were added to the system. This biopreparation also accelerated emulsification of the oil without any negative effects to the natural microbiota. The biological oxygen demand at five days and at the end of the experiment was determined. The biodegradation constant and the biochemical stabilization constant were also measured. 14 refs., 5 tabs., 4 figs.

  7. PHA production by mixed cultures: a way to valorize wastes from pulp industry.

    Science.gov (United States)

    Queirós, Diogo; Rossetti, Simona; Serafim, Luísa S

    2014-04-01

    In this work, hardwood spent sulfite liquor (HSSL), a complex feedstock originating from the pulp industry, was tested for the first time as a substrate for polyhydroxyalkanoate (PHA) production by a mixed microbial culture (MMC) under aerobic dynamic feeding (ADF) conditions. A sequencing batch reactor (SBR) fed with HSSL was operated for 67days and the selected MMC reached a maximum PHA content of 67.6%. The MMC demonstrated a differential utilization of the carbon sources present in HSSL. Acetic acid was fully consumed, while xylose and lignosulphonates were partially consumed (30% and 14%, respectively). The selected culture was characterized by Fluorescence in Situ Hybridization (FISH). Bacteria belonging to the three main classes were identified: Alpha- (72.7±4.0%), Beta- (11.1±0.37%) and Gammaproteobacteria (10.3±0.3%). Within Alphaproteobacteria, a small amount of Paracoccus (4.2±0.51%) and Defluvicoccus related to Tetrad Forming Organisms (9.0±0.28%) were detected. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Characterization of microbial compositions in a thermophilic chemostat of mixed culture fermentation.

    Science.gov (United States)

    Zhang, Fang; Yang, Jing-Hua; Dai, Kun; Chen, Yun; Li, Qiu-Rong; Gao, Fa-Ming; Zeng, Raymond J

    2016-02-01

    The microbial community compositions of a chemostat enriched in a thermophilic (55 °C) mixed culture fermentation (MCF) for hydrogen production under different operational conditions were revealed in this work by integrating denaturing gradient gel electrophoresis (DGGE), Illumina Miseq high-throughput sequencing, and 16S rRNA clone library sequencing. The results showed that the community structure of the enriched cultures was relatively simple. Clones close to the genera of Thermoanaerobacter and/or Bacillus mainly dominated the bacteria. And homoacetogens and archaea were washed out and not detected even by Illumina Miseq high-throughput sequencing which supported the benefit for hydrogen production. On the other hand, the results revealed that the metabolic shift was clearly associated with the change of dominated bacterial groups. The effects of hydrogen partial pressure (PH2) and pH from 4.0 to 5.5 on the microbial compositions were not notable and Thermoanaerobacter was dominant, thus, the metabolites were also not changed. While Bacillus, Thermoanaerobacter and Propionispora hippei dominated the bacteria communities at neutral pH, or Bacillus and Thermoanaerobacter dominated at high influent glucose concentrations, consequently the main metabolites shifted to acetate, ethanol, propionate, or lactate. Thereby, the effect of microbial composition on the metabolite distribution and shift shall be considered when modeling thermophilic MCF in the future.

  9. Production of polyhydroxybutyrates and carbohydrates in a mixed cyanobacterial culture: Effect of nutrients limitation and photoperiods.

    Science.gov (United States)

    Arias, Dulce María; Uggetti, Enrica; García-Galán, María Jesús; García, Joan

    2018-05-25

    In the present study, different photoperiods and nutritional conditions were applied to a mixed wastewater-borne cyanobacterial culture in order to enhance the intracellular accumulation of polyhydroxybutyrates (PHBs) and carbohydrates. Two different experimental set-ups were used. In the first, the culture was permanently exposed to illumination, while in the second it was submitted to light/dark alternation (12 h cycles). In both cases, two different nutritional regimes were also evaluated, N-limitation and P-limitation. Results showed that the highest PHB concentration (104 mg L -1 ) was achieved under P limited conditions and permanent illumination, whereas the highest carbohydrate concentration (838 mg L -1 ) was obtained under N limited condition and light/dark alternation. With regard to bioplastics and biofuel generation, this study demonstrates that the accumulation of PHBs (bioplastics) and carbohydrates (potential biofuel substrate) is favored in wastewater-borne cyanobacteria under conditions where nutrients are limited. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Spatial distributions of Pseudomonas fluorescens colony variants in mixed-culture biofilms.

    Science.gov (United States)

    Workentine, Matthew L; Wang, Siyuan; Ceri, Howard; Turner, Raymond J

    2013-07-28

    The emergence of colony morphology variants in structured environments is being recognized as important to both niche specialization and stress tolerance. Pseudomonas fluorescens demonstrates diversity in both its natural environment, the rhizosphere, and in laboratory grown biofilms. Sub-populations of these variants within a biofilm have been suggested as important contributors to antimicrobial stress tolerance given their altered susceptibility to various agents. As such it is of interest to determine how these variants might be distributed in the biofilm environment. Here we present an analysis of the spatial distribution of Pseudomonas fluorescens colony morphology variants in mixed-culture biofilms with the wildtype phenotype. These findings reveal that two variant colony morphotypes demonstrate a significant growth advantage over the wildtype morphotype in the biofilm environment. The two variant morphotypes out-grew the wildtype across the entire biofilm and this occurred within 24 h and was maintained through to 96 h. This competitive advantage was not observed in homogeneous broth culture. The significant advantage that the variants demonstrate in biofilm colonization over the wildtype denotes the importance of this phenotype in structured environments.

  11. Enhanced biodegradation of Pina Cuban crude oil by a culture of mixed marine bacteria

    International Nuclear Information System (INIS)

    Joseph, I.N.; Perigo, E.; Bergueiro, J.R.; Pita, A.; Mayol, M.A.; Navarro, A.

    1998-01-01

    The ability of a mixed marine bacteria culture to degrade Pina Cuban crude oil in the presence of nutrients and sea water was studied. Laboratory experiments were conducted in flasks with 100 ml of saline liquid containing 1 per cent crude. The flasks were inoculated with marine bacteria (IDO-225, IDO-226, and IDO-229) at a final concentration of 10 6 cell/ml. The cultures were grown at 29 degrees C for 21 days. Bacterial growth, and surface and interfacial tension were measured after 5, 13 and 21 days. Results showed that the marine bacteria were effective in accelerating the biodegradation process of Pina Cuban oil. The efficiency of the process increased when nutrients were added to the system. This biopreparation also accelerated emulsification of the oil without any negative effects to the natural microbiota. The biological oxygen demand at five days and at the end of the experiment was determined. The biodegradation constant and the biochemical stabilization constant were also measured. 14 refs., 5 tabs., 4 figs

  12. Lactic acid production from potato peel waste by anaerobic sequencing batch fermentation using undefined mixed culture.

    Science.gov (United States)

    Liang, Shaobo; McDonald, Armando G; Coats, Erik R

    2015-11-01

    Lactic acid (LA) is a necessary industrial feedstock for producing the bioplastic, polylactic acid (PLA), which is currently produced by pure culture fermentation of food carbohydrates. This work presents an alternative to produce LA from potato peel waste (PPW) by anaerobic fermentation in a sequencing batch reactor (SBR) inoculated with undefined mixed culture from a municipal wastewater treatment plant. A statistical design of experiments approach was employed using set of 0.8L SBRs using gelatinized PPW at a solids content range from 30 to 50 g L(-1), solids retention time of 2-4 days for yield and productivity optimization. The maximum LA production yield of 0.25 g g(-1) PPW and highest productivity of 125 mg g(-1) d(-1) were achieved. A scale-up SBR trial using neat gelatinized PPW (at 80 g L(-1) solids content) at the 3 L scale was employed and the highest LA yield of 0.14 g g(-1) PPW and a productivity of 138 mg g(-1) d(-1) were achieved with a 1 d SRT. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Consolidated Bioprocessing for Butyric Acid Production from Rice Straw with Undefined Mixed Culture.

    Science.gov (United States)

    Ai, Binling; Chi, Xue; Meng, Jia; Sheng, Zhanwu; Zheng, Lili; Zheng, Xiaoyan; Li, Jianzheng

    2016-01-01

    Lignocellulosic biomass is a renewable source with great potential for biofuels and bioproducts. However, the cost of cellulolytic enzymes limits the utilization of the low-cost bioresource. This study aimed to develop a consolidated bioprocessing without the need of supplementary cellulase for butyric acid production from lignocellulosic biomass. A stirred-tank reactor with a working volume of 21 L was constructed and operated in batch and semi-continuous fermentation modes with a cellulolytic butyrate-producing microbial community. The semi-continuous fermentation with intermittent discharging of the culture broth and replenishment with fresh medium achieved the highest butyric acid productivity of 2.69 g/(L· d). In semi-continuous operation mode, the butyric acid and total carboxylic acid concentrations of 16.2 and 28.9 g/L, respectively, were achieved. Over the 21-day fermentation period, their cumulative yields reached 1189 and 2048 g, respectively, corresponding to 41 and 74% of the maximum theoretical yields based on the amount of NaOH pretreated rice straw fed in. This study demonstrated that an undefined mixed culture-based consolidated bioprocessing for butyric acid production can completely eliminate the cost of supplementary cellulolytic enzymes.

  14. Anaerobic methanotrophic communities thrive in deep submarine permafrost.

    Science.gov (United States)

    Winkel, Matthias; Mitzscherling, Julia; Overduin, Pier P; Horn, Fabian; Winterfeld, Maria; Rijkers, Ruud; Grigoriev, Mikhail N; Knoblauch, Christian; Mangelsdorf, Kai; Wagner, Dirk; Liebner, Susanne

    2018-01-22

    Thawing submarine permafrost is a source of methane to the subsurface biosphere. Methane oxidation in submarine permafrost sediments has been proposed, but the responsible microorganisms remain uncharacterized. We analyzed archaeal communities and identified distinct anaerobic methanotrophic assemblages of marine and terrestrial origin (ANME-2a/b, ANME-2d) both in frozen and completely thawed submarine permafrost sediments. Besides archaea potentially involved in anaerobic oxidation of methane (AOM) we found a large diversity of archaea mainly belonging to Bathyarchaeota, Thaumarchaeota, and Euryarchaeota. Methane concentrations and δ 13 C-methane signatures distinguish horizons of potential AOM coupled either to sulfate reduction in a sulfate-methane transition zone (SMTZ) or to the reduction of other electron acceptors, such as iron, manganese or nitrate. Analysis of functional marker genes (mcrA) and fluorescence in situ hybridization (FISH) corroborate potential activity of AOM communities in submarine permafrost sediments at low temperatures. Modeled potential AOM consumes 72-100% of submarine permafrost methane and up to 1.2 Tg of carbon per year for the total expected area of submarine permafrost. This is comparable with AOM habitats such as cold seeps. We thus propose that AOM is active where submarine permafrost thaws, which should be included in global methane budgets.

  15. Windrow composting mitigated CH4 emissions: characterization of methanogenic and methanotrophic communities in manure management.

    Science.gov (United States)

    Chen, Ruirui; Wang, Yiming; Wei, Shiping; Wang, Wei; Lin, Xiangui

    2014-12-01

    With increasing livestock breeding, methane (CH4 ) emissions from manure management will increasingly contribute more to atmospheric CH4 concentration. The dynamics of methanogens and methanotrophs have not yet been studied in the manure environment. The current study combines surface CH4 emissions with methanogenic and methanotrophic community analyses from two management practices, windrow composting (WCOM) and solid storage (SSTO). Our results showed that there was an c. 50% reduction of CH4 emissions with WCOM compared with SSTO over a 50-day period. A sharp decrease in the quantities of both methanogens and methanotrophs in WCOM suggested that CH4 mitigation was mainly due to decreased CH4 production rather than increased CH4 oxidation. Pyrosequencing analysis demonstrated that aeration caused a clear shift of dominant methanogens in the manure, with specifically a significant decrease in Methanosarcina and increase in Methanobrevibacter. The composition of methanogenic community was influenced by manure management and regulated CH4 production. A sharp increase in the quantity of methanotrophs in SSTO suggested that microbial CH4 oxidation is an important sink for the CH4 produced. The increased abundance of Methylococcaceae in SSTO suggested that Type I methanotrophs have an advantage in CH4 oxidation in occupying niches under low CH4 and high O2 conditions. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  16. Peatland succession induces a shift in the community composition of Sphagnum-associated active methanotrophs.

    Science.gov (United States)

    Putkinen, Anuliina; Larmola, Tuula; Tuomivirta, Tero; Siljanen, Henri M P; Bodrossy, Levente; Tuittila, Eeva-Stiina; Fritze, Hannu

    2014-06-01

    Sphagnum-associated methanotrophs (SAM) are an important sink for the methane (CH4) formed in boreal peatlands. We aimed to reveal how peatland succession, which entails a directional change in several environmental variables, affects SAM and their activity. Based on the pmoA microarray results, SAM community structure changes when a peatland develops from a minerotrophic fen to an ombrotrophic bog. Methanotroph subtypes Ia, Ib, and II showed slightly contrasting patterns during succession, suggesting differences in their ecological niche adaptation. Although the direct DNA-based analysis revealed a high diversity of type Ib and II methanotrophs throughout the studied peatland chronosequence, stable isotope probing (SIP) of the pmoA gene indicated they were active mainly during the later stages of succession. In contrast, type Ia methanotrophs showed active CH4 consumption in all analyzed samples. SIP-derived (13)C-labeled 16S rRNA gene clone libraries revealed a high diversity of SAM in every succession stage including some putative Methylocella/Methyloferula methanotrophs that are not detectable with the pmoA-based approach. In addition, a high diversity of 16S rRNA gene sequences likely representing cross-labeled nonmethanotrophs was discovered, including a significant proportion of Verrucomicrobia-related sequences. These results help to predict the effects of changing environmental conditions on SAM communities and activity. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  17. Physical disturbance to ecological niches created by soil structure alters community composition of methanotrophs.

    Science.gov (United States)

    Kumaresan, Deepak; Stralis-Pavese, Nancy; Abell, Guy C J; Bodrossy, Levente; Murrell, J Colin

    2011-10-01

    Aggregates of different sizes and stability in soil create a composite of ecological niches differing in terms of physico-chemical and structural characteristics. The aim of this study was to identify, using DNA-SIP and mRNA-based microarray analysis, whether shifts in activity and community composition of methanotrophs occur when ecological niches created by soil structure are physically perturbed. Landfill cover soil was subject to three treatments termed: 'control' (minimal structural disruption), 'sieved' (sieved soil using 2 mm mesh) and 'ground' (grinding using mortar and pestle). 'Sieved' and 'ground' soil treatments exhibited higher methane oxidation potentials compared with the 'control' soil treatment. Analysis of the active community composition revealed an effect of physical disruption on active methanotrophs. Type I methanotrophs were the most active methanotrophs in 'sieved' and 'ground' soil treatments, whereas both Type I and Type II methanotrophs were active in the 'control' soil treatment. The result emphasize that changes to a particular ecological niche may not result in an immediate change to the active bacterial composition and change in composition will depend on the ability of the bacterial communities to respond to the perturbation. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  18. Exploitation of sweet sorghum biomass for biofuel production using mixed acidogenic and methanogenic cultures and pure cultures of ruminococcus albus

    International Nuclear Information System (INIS)

    Ntaikou, I.; Antonopoulou, G.; Marazioti, C.; Lyberatos, G.

    2008-01-01

    Full text: The present study focuses on the exploitation of sweet sorghum biomass for gas biofuel production in continuous and batch systems. Sweet sorghum is an annual C 4 plant of tropical origin, well-adapted to sub-tropical and temperate regions and highly productive in biomass. It is rich in readily fermentable sugars and thus it can be considered as an excellent raw material for biohydrogen production from many different fermentative microorganisms. Extraction of free sugars from the sorghum stalks was achieved using water at 30 degrees centigrade. After the extraction process a liquid fraction (sorghum extract), rich in sucrose, and a solid fraction (sorghum cellulosic-hemicellulosic residues or sorghum bagasse), containing the cellulose and hemicelluloses, were obtained. A two-step continuous process was developed for the biological hydrogen production and the subsequent production of biogas from sweet sorghum extract. In the first reactor sugars were fermented to hydrogen, volatile fatty acids and alcohols b mixed acidogenic culture derived from the indigenous microfauna of sweet sorghum. The hydrogen producing reactor was operated at five different hydraulic retention times (HRT), i.e 24h, 12h, 8h, 6h and 4h. The HRT of 12h proved to be the most effective leading to the production 10.4 L H 2 /kg sweet sorghum biomass. Subsequently, the effluent was fed to the methanogenic reactor, where all the residual organic compounds were digested by an acclimated methanogenic culture derived from activated sludge. The operation of the methanogenic reactor was studied at three different HRTs, i.e 20d, 15d and 10d with the latter being the most prosing leading to the production 35.2 L CH 4 /kg sweet sorghum biomass. Both continuous and batch cultures were used for the investigation of hydrogen production from sweet sorghum biomass using Ruminococcus albus. R. albus is an important, fibrolytic bacterium of the rumen that can hydrolyse both cellulose and hemicellulose

  19. To a cultural perspective of mixed reality events: a case study of event overflow in operas and concerts in mixed reality

    Science.gov (United States)

    Lucas, Jean-François; Cornish, Tracy; Margolis, Todd

    2012-12-01

    Mixed reality defines the sharing of a space-time between the real and the virtual world. The definition of this concept is further extended when virtual worlds such as Second Life® (SL) are included. Through cultural events such as concerts and operas, we will see that the main goal of these kinds of projects is not simply to offer a video and audio broadcast of these events in the digital dimension. The current challenge is to create interactions between the individuals who are in different shared spaces. By studying the unfolding of these events in its various phases-before, during, and after-we examine the culture of the event. We question how the culture of the event can be transposed in a mixed reality display, and how this kind of event can affect people on both sides of the "membrane" made by the technical configuration. Beyond the alignments and adjustments that we can see between the different individuals involved in these events, we examine more broadly the changes and mutations of the culture of the event in this specific configuration.

  20. Draft Genome Sequence of Methyloferula stellata AR4, an Obligate Methanotroph Possessing Only a Soluble Methane Monooxygenase.

    Science.gov (United States)

    Dedysh, Svetlana N; Naumoff, Daniil G; Vorobev, Alexey V; Kyrpides, Nikos; Woyke, Tanja; Shapiro, Nicole; Crombie, Andrew T; Murrell, J Colin; Kalyuzhnaya, Marina G; Smirnova, Angela V; Dunfield, Peter F

    2015-03-05

    Methyloferula stellata AR4 is an aerobic acidophilic methanotroph, which, in contrast to most known methanotrophs but similar to Methylocella spp., possesses only a soluble methane monooxygenase. However, it differs from Methylocella spp. by its inability to grow on multicarbon substrates. Here, we report the draft genome sequence of this bacterium. Copyright © 2015 Dedysh et al.

  1. Draft Genome Sequence of Methyloferula stellata AR4, an Obligate Methanotroph Possessing Only a Soluble Methane Monooxygenase

    OpenAIRE

    Dedysh, Svetlana N.; Naumoff, Daniil G.; Vorobev, Alexey V.; Kyrpides, Nikos; Woyke, Tanja; Shapiro, Nicole; Crombie, Andrew T.; Murrell, J. Colin; Kalyuzhnaya, Marina G.; Smirnova, Angela V.; Dunfield, Peter F.

    2015-01-01

    Methyloferula stellata AR4 is an aerobic acidophilic methanotroph, which, in contrast to most known methanotrophs but similar to Methylocella spp., possesses only a soluble methane monooxygenase. However, it differs from Methylocella spp. by its inability to grow on multicarbon substrates. Here, we report the draft genome sequence of this bacterium.

  2. Effects of nitrogen load on the function and diversity of methanotrophs in the littoral wetland of a boreal lake

    Directory of Open Access Journals (Sweden)

    Henri MP Siljanen

    2012-02-01

    Full Text Available Methane is the second most abundant greenhouse gas in the atmosphere. A major part of the total methane emissions from lake ecosystems are emitted from littoral wetlands. Methane emissions are significantly reduced by methanotrophs as they use methane as the sole energy and carbon source. Function of methanotrophs can be either activated or suppressed by nitrogen. However, the effects of nitrogen on methanotrophs in littoral wetlands are unknown. Here we report how nitrogen loading in situ affected the function and diversity of methanotrophs in a littoral wetland. Methanotrophic community composition and functional diversity were analyzed with particulate methane monooxygenase (pmoA gene targeted microarray. Nitrogen load had no effects on methane oxidation potential and methane fluxes. Nitrogen load activated pmoA gene transcription of type I (Methylobacter, Methylomonas and LW21-freshwater phylotypes methanotrophs, but decreased the relative abundance of type II (Methylocystis, Methylosinus trichosporium and Methylosinus phylotypes methanotrophs. Hence, the overall activity of a methanotroph community in littoral wetlands is unlikely to be affected by nitrogen leached from the catchment area.

  3. Standardisation vs. adaption : a conjoint experiment on the influence of psychic, cultural and geographical distance on international marketing mix decisions

    NARCIS (Netherlands)

    Kraus, Sascha; Meier, Fabian; Eggers, Felix; Bouncken, Ricarda B.; Schuessler, Felix

    2016-01-01

    This paper delivers new insights into how psychic, cultural and geographical distance influence international marketing mix decisions on the basis of a choice-based conjoint analysis with 96 managers from Switzerland and Liechtenstein. In this experiment, the managers had to decide whether the four

  4. Exploring the response process of culturally differing survey respondents with a response style: A sequential mixed-methods study

    NARCIS (Netherlands)

    Morren, M.H.; Gelissen, J.P.T.M.; Vermunt, J.K.

    2013-01-01

    This article presents a mixed methods approach that integrates quantitative and qualitative methods to analyze why the four largest minorities in the Netherlands-Turks, Moroccans, Antilleans, and Surinamese-respond differently to items treating cultural topics. First, we conducted latent class

  5. Direct 16S rRNA gene sequencing of polymicrobial culture-negative samples with analysis of mixed chromatograms

    DEFF Research Database (Denmark)

    Hartmeyer, Gitte N; Justesen, Ulrik S

    2010-01-01

    Two cases involving polymicrobial culture-negative samples were investigated by 16S rRNA gene sequencing, with analysis of mixed chromatograms. Fusobacterium necrophorum, Prevotella intermedia and Streptococcus constellatus were identified from pleural fluid in a patient with Lemierre's syndrome...

  6. Feasibility study of an alkaline-based chemical treatment for the purification of polyhydroxybutyrate produced by a mixed enriched culture

    NARCIS (Netherlands)

    Jiang, Y.; Mikova, G.; Kleerebezem, R.; van der Wielen, L.A.M.; Cuellar, M.C.

    2015-01-01

    This study focused on investigating the feasibility of purifying polyhydroxybutyrate (PHB) from mixed culture biomass by alkaline-based chemical treatment. The PHB-containing biomass was enriched on acetate under non-sterile conditions. Alkaline treatment (0.2 M NaOH) together with surfactant SDS

  7. Feasibility study of an alkaline-based chemical treatment for the purification of polyhydroxybutyrate produced by a mixed enriched culture

    NARCIS (Netherlands)

    Jiang, Y.; Mikova, G.; Kleerebezem, R.; Van der Wielen, L.A.M.; Cuellar Soares, M.C.

    2015-01-01

    This study focused on investigating the feasibility of purifying polyhydroxybutyrate (PHB) from mixed culture biomass by alkaline-based chemical treatment. The PHB-containing biomass was enriched on acetate under non-sterile conditions. Alkaline treatment (0.2 M NaOH) together with surfactant SDS

  8. Using Mixed Methods Research to Examine the Benefits of Culturally Relevant Instruction on Latino Students' Writing Skills

    Science.gov (United States)

    Murphy, Joel P.; Murphy, Shirley A.

    2016-01-01

    A convergent mixed methods research design addressed the extent of benefit obtained from reading culturally inclusive prompts (i.e., four brief essays written by Latino authors) to improve essay writing in a developmental (pre-college) English course. Participants were 45 Latino students who provided quantitative data. Chi square analysis showed…

  9. Identification of the dominant sulfate-reducing bacterial partner of anaerobic methanotrophs of the ANME-2 clade.

    Science.gov (United States)

    Schreiber, Lars; Holler, Thomas; Knittel, Katrin; Meyerdierks, Anke; Amann, Rudolf

    2010-08-01

    The anaerobic oxidation of methane (AOM) with sulfate as terminal electron acceptor is mediated by consortia of methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB). Whereas three clades of ANME have been repeatedly studied with respect to phylogeny, key genes and genomic capabilities, little is known about their sulfate-reducing partner. In order to identify the partner of anaerobic methanotrophs of the ANME-2 clade, bacterial 16S rRNA gene libraries were constructed from cultures highly enriched for ANME-2a and ANME-2c in consortia with Deltaproteobacteria of the Desulfosarcina/Desulfococcus group (DSS). Phylogenetic analysis of those and publicly available sequences from AOM sites supported the hypothesis by Knittel and colleagues that the DSS partner belongs to the diverse SEEP-SRB1 cluster. Six subclusters of SEEP-SRB1, SEEP-SRB1a to SEEP-SRB1f, were proposed and specific oligonucleotide probes were designed. Using fluorescence in situ hybridization on samples from six different AOM sites, SEEP-SRB1a was identified as sulfate-reducing partner in up to 95% of total ANME-2 consortia. SEEP-SRB1a cells exhibited a rod-shaped, vibrioid, or coccoid morphology and were found to be associated with subgroups ANME-2a and ANME-2c. Moreover, SEEP-SRB1a was also detected in 8% to 23% of ANME-3 consortia in Haakon Mosby Mud Volcano sediments, previously described to be predominantly associated with SRB of the Desulfobulbus group. SEEP-SRB1a contributed to only 0.3% to 0.7% of all single cells in almost all samples indicating that these bacteria are highly adapted to a symbiotic relationship with ANME-2. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

  10. Degradation of soil cyanide by single and mixed cultures of Pseudomonas stutzeri and Bacillus subtilis.

    Science.gov (United States)

    Nwokoro, Ogbonnaya; Dibua, Marie Esther Uju

    2014-03-01

    The aim of this investigation was to study whether certain bacteria could be used for cyanide degradation in soil. The bacteria Pseudomonas stutzeri and Bacillus subtilis were selected based on their good growth in a minimal medium containing 0.8 mg mL-1 potassium cyanide (KCN). In this study we tested their ability to reduce cyanide levels in a medium containing 1.5 mg mL-1 of KCN. Although both microorganisms reduced cyanide levels, Pseudomonas stutzeri was the more effective test organism. Later on, the selected cultures were grown, diluted and their various cell concentrations were used individually and in combination to test their ability of cyanide degradation in soil samples collected around a cassava processing mill. Bacillus subtilis caused degradation of soil cyanide from 0.218 mg g-1 soil immediately with an inoculum concentration of 0.1 (OD600nm) to 0.072 mg g-1 soil after 10 days with an inoculum concentration of 0.6 (OD600nm) implying a 66.9 % reduction. Pseudomonas stutzeri cell concentration of 0.1 (OD600nm) decreased soil cyanide from 0.218 mg g-1 soil initially to 0.061 mg g-1 soil after 10 days with an inoculum concentration of 0.6 (OD600nm) (72 % reduction). The mixed culture of the two bacteria produced the best degradation of soil cyanide from 0.218 mg g-1 soil sample with a combined inoculum concentration of 0.1 (OD600nm) initially to 0.025 mg g-1 soil with a combined inoculum concentration of 0.6 (OD600nm) after 10 days incubation resulting in an 88.5 % degradation of soil cyanide. The analysed bacteria displayed high cyanide degradation potential and may be useful for efficient decontamination of cyanide contaminated sites.

  11. Potentials of using mixed culture bacteria incorporated with sodium bicarbonate for hydrogen production from water hyacinth.

    Science.gov (United States)

    Wazeri, Alaa; Elsamadony, Mohamed; Roux, Sophie Le; Peu, Pascal; Tawfik, Ahmed

    2018-05-08

    The aim of this study is to assess the potentials of using mixed culture bacteria incorporated with different concentrations of NaHCO 3 for hydrogen production from water hyacinth (WH). The lowest hydrogen yield (HY) of 30.4 ± 1.9 mL/g TVS , H 2 content (HC) of 19.5 ± 1.5% and hydrogenase enzyme (HE) activity of 0.06 ± 0.01 mgM.B reduced /min were registered for the cultures without supplementation of NaHCO 3 . The HY, HC, and HE activity were maximized at levels of 69.2 ± 4.3 mL/g TVS, 58.4 ± 3.6% and 0.18 ± 0.01 mgM.B reduced /min. respectively for the anaerobes supplied with 3.0 g NaHCO 3 /L. Furthermore, cellulose, hemicellulose, and lignin destruction efficiencies were 37.2 ± 2.3, 30.0 ± 1.9 and 20.9 ± 1.3% respectively due to the increase of cellulase and xylanase activities up to 2.73 ± 0.17 and 1.87 ± 0.12 U/mL, respectively. Moreover, the abundance of Firmicutes was substantially increased and accounted for 71% of the total OTU's. Microbes belonging to the order Clostridiales and OPB54 were particularly enriched in the medium supplemented with NaHCO 3 . Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Improving flavor metabolism of Saccharomyces cerevisiae by mixed culture with Bacillus licheniformis for Chinese Maotai-flavor liquor making.

    Science.gov (United States)

    Meng, Xing; Wu, Qun; Wang, Li; Wang, Diqiang; Chen, Liangqiang; Xu, Yan

    2015-12-01

    Microbial interactions could impact the metabolic behavior of microbes involved in food fermentation, and therefore they are important for improving food quality. This study investigated the effect of Bacillus licheniformis, the dominant bacteria in the fermentation process of Chinese Maotai-flavor liquor, on the metabolic activity of Saccharomyces cerevisiae. Results indicated that S. cerevisiae inhibited the growth of B. licheniformis in all mixed culture systems and final viable cell count was lower than 20 cfu/mL. Although growth of S. cerevisiae was barely influenced by B. licheniformis, its metabolism was changed as initial inoculation ratio varied. The maximum ethanol productions were observed in S. cerevisiae and B. licheniformis at 10(6):10(7) and 10(6):10(8) ratios and have increased by 16.8 % compared with single culture of S. cerevisiae. According to flavor compounds, the culture ratio 10(6):10(6) showed the highest level of total concentrations of all different kinds of flavor compounds. Correlation analyses showed that 12 flavor compounds, including 4 fatty acids and their 2 corresponding esters, 1 terpene, and 5 aromatic compounds, that could only be produced by S. cerevisiae were significantly correlated with the initial inoculation amount of B. licheniformis. These metabolic changes in S. cerevisiae were not only a benefit for liquor aroma, but may also be related to its inhibition effect in mixed culture. This study could help to reveal the microbial interactions in Chinese liquor fermentation and provide guidance for optimal arrangement of mixed culture fermentation systems.

  13. The relationship between Mexican American cultural values and resilience among Mexican American college students: a mixed methods study.

    Science.gov (United States)

    Morgan Consoli, Melissa L; Llamas, Jasmin D

    2013-10-01

    The current study investigated the role of cultural values in the resilience of Mexican American college students. Utilizing mixed methodology, 124 self-identified Mexican American college students were asked to complete an online survey, including a demographic questionnaire, the Resilience Scale, Mexican American Cultural Values Scale, and 2 open-ended questions concerning overcoming adversity and cultural values. As hypothesized, Mexican American traditional cultural values (Familismo, Respeto, Religiosidad, and Traditional Gender Roles) predicted resilience, with Familismo accounting for the majority of the variance. Consensual qualitative research (Hill, Thompson, & Nutt Williams, 1997) was used to identify emergent domains and themes within the open-ended question responses. Traditional Mexican American Value themes included Familismo, Ethnic Identity, Religiosidad, Perseverance, and Respeto. Results highlight the important role that certain Mexican American cultural values play in providing strength for overcoming adversities.

  14. Effect of biofilm and selective mixed culture on microbial fuel cell for the treatment of tempeh industrial wastewater

    Science.gov (United States)

    Arbianti, Rita; Surya Utami, Tania; Leondo, Vifki; Elisabeth; Andyah Putri, Syafira; Hermansyah, Heri

    2018-03-01

    Microbial Fuel Cell (MFC) provides a new alternative in the treatment of organic waste. MFC produces 50-90% less sludge to be disposed than other methods. MFC technology can utilize existing microorganisms in the waste as a catalyst to generate electricity and simultaneously also serves as a wastewater treatment unit itself. Tempeh wastewater is one of the abundant industrial wastewater which can be processed using MFC. Research using the selective mixed culture is very likely to do due to the good result on COD removals by adding mixed culture. Microorganisms in tempeh wastewater consist of bacteria gram positive and gram negative. This study focused on the aspects of waste treatment which is determined by decreased levels of COD and BOD. Variations in this study are the formation time of biofilm and the addition of selective gram. MFC operated for 50 hours. For a variation of biofilm formation, experiments were performed after incubation by replacing incubation substrates used in the formation of biofilms. Biofilm formation time in this study was 3 days, 5 days, 7 days and 14 days. Gram positive and gram negative bacteria were used in selective mixed culture experiments. Selective mixed culture added to the reactor by 1 mL and 5 mL. Selection of gram-positive or gram-negative bacteria carried by growing mixed culture on selective media. COD and BOD levels were measured in the wastewater before and after the experiment conducted in each variation. Biofilm formation optimum time is 7 days which decrease COD and BOD levels by 18.2% and 35.9%. The addition of gram negative bacteria decreases COD and BOD levels by 29.32% and 51.32%. Further research is needed in order to get a better result on decreasing levels of COD and BOD.

  15. Aculturation In Mixed Marriage Family A Case Study In The Inter - Cultural Communication In Javanese And Tionghoa In Medan

    Directory of Open Access Journals (Sweden)

    Anang Jati Kurniawan

    2017-07-01

    Full Text Available The objective of the research was to find out inter-cultural communicative activity in a family of mixed marriages between two different culture Javanese and Tionghoa. The research subject was a married couple who had been married for 21 years. The husband was a Tionghoa and the wife was a Javanese. The research used interpretative paradigm with phenomenological approach. The final objective of phenomenal data analysis was to present the deep analytic description of the communicative inter-cultural phenomenon of the mixed-marriage. The result of the research showed that 1 the respondents always attempted to pay attention to anything outside themselves did not give any negative comments and were ready to listen to each other 2 were tolerant to the spouses ambiguity respected to each other did not coerce personal belief and 3 showed empathy and were willing to get involved in the spouses activity.

  16. Shifts in identity and activity of methanotrophs in arctic lake sediments in response to temperature changes

    Science.gov (United States)

    He, Ruo; Wooller, Matthew J.; Pohlman, John W.; Quensen, John; Tiedje, James M.; Leigh, Mary Beth

    2012-01-01

    Methane (CH4) flux to the atmosphere is mitigated via microbial CH4 oxidation in sediments and water. As arctic temperaturesincrease, understanding the effects of temperature on the activity and identity of methanotrophs in arctic lake sediments is importantto predicting future CH4 emissions. We used DNA-based stable-isotope probing (SIP), quantitative PCR (Q-PCR), andpyrosequencing analyses to identify and characterize methanotrophic communities active at a range of temperatures (4°C, 10°C,and 21°C) in sediments (to a depth of 25 cm) sampled from Lake Qalluuraq on the North Slope of Alaska. CH4 oxidation activitywas measured in microcosm incubations containing sediments at all temperatures, with the highest CH4 oxidation potential of37.5 mol g1 day1 in the uppermost (depth, 0 to 1 cm) sediment at 21°C after 2 to 5 days of incubation. Q-PCR of pmoA and ofthe 16S rRNA genes of type I and type II methanotrophs, and pyrosequencing of 16S rRNA genes in 13C-labeled DNA obtained bySIP demonstrated that the type I methanotrophs Methylobacter, Methylomonas, and Methylosoma dominated carbon acquisitionfrom CH4 in the sediments. The identity and relative abundance of active methanotrophs differed with the incubation temperature.Methylotrophs were also abundant in the microbial community that derived carbon from CH4, especially in the deeper sediments(depth, 15 to 20 cm) at low temperatures (4°C and 10°C), and showed a good linear relationship (R0.82) with the relativeabundances of methanotrophs in pyrosequencing reads. This study describes for the first time how methanotrophiccommunities in arctic lake sediments respond to temperature variations.

  17. The lipid response of aerobic marine methanotroph communities under changing environmental conditions.

    Science.gov (United States)

    Rush, D.; Villanueva, L.; van der Meer, M.; S Sinninghe Damsté, J.

    2017-12-01

    Methane (CH4) originating from marine environments accounts for a significant amount of atmospheric greenhouse gas. Aerobic methanotrophs, which convert CH4 to CO­2, are responsible for quenching a part of this methane before its release. Modern-day climate projections show a rapid shift towards a warmer, more acidic ocean. How do these important methanotrophic communities respond to such changes to their environment? Here, we present the results of microcosm experiments from three marine regions influenced by CH4. Particulate organic matter and sediment were collected from the Black Sea, the Baltic Sea, and the North Sea, at depths ideal for aerobic methanotroph communities at the time of sampling (e.g. oxic, in area of active CH4 release). These were incubated under different temperatures, pHs, and labelled 13CH4 concentrations. We monitored methane concentration in these microcosms as an indication of 13CH4 consumption by methanotrophs. Once the methane concentration was lipids of the organisms oxidising methane in order to elucidate which organisms are performing methane oxidation and whether they synthesize specific biomarker lipids. Particular attention will be paid to the abundances and diversity of bacteriohopanepolyol lipids, known methanotroph biomarkers. The ultimate goal of our investigation is to determine the effect changes in these environmental parameters have on aerobic methanotroph community structures and their lipid fingerprints. By establishing reliable biomarker lipids for aerobic methanotrophy at certain conditions, we will then be able to investigate the contribution of aerobic methanotrophy throughout Earth's history, especially at times when CH4 concentrations were higher than they are at present.

  18. Reconstituted yogurt from yogurt cultured milk powder mix has better overall characteristics than reconstituted yogurt from commercial yogurt powder.

    Science.gov (United States)

    Song, Lijie; Aryana, Kayanush J

    2014-10-01

    For manufacture of commercial yogurt powder, yogurt has to go through a drying process, which substantially lowers the yogurt culture counts, so the potential health benefits of the yogurt culture bacteria are reduced. Also, upon reconstitution, commercial yogurt powder does not taste like yogurt and has an off-flavor. The objective was to study the microbial, physicochemical, and sensory characteristics of reconstituted yogurt from yogurt cultured milk powder (YCMP) mix and reconstituted yogurt from commercial yogurt powder (CYP). The CYP reconstituted yogurt was the control and YCMP mix reconstituted yogurt was the treatment. Microbial and physicochemical characteristics of the CYP reconstituted yogurt and YCMP mix reconstituted yogurt were analyzed daily for the first week and then weekly for a period of 8 wk. Sensory consumer testing of CYP reconstituted yogurt and YCMP mix reconstituted yogurt was conducted with 100 consumers. At 56 d, YCMP mix reconstituted yogurt had 5 log cfu/mL higher counts of Streptococcus thermophilus than the control (CYP reconstituted yogurt). Also, Lactobacillus bulgaricus counts of YCMP mix reconstituted yogurt were 6.55 log cfu/mL at 28 d and were 5.35 log cfu/mL at 56 d, whereas the CYP reconstituted yogurt from 28 d onwards had a count of yogurt also had significantly higher apparent viscosity and sensory scores for appearance, color, aroma, taste, thickness, overall liking, consumer acceptability, and purchase intent than CYP reconstituted yogurt. Overall, YCMP mix reconstituted yogurt had more desirable characteristics than CYP reconstituted yogurt. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  19. Co-Bioleaching of Chalcopyrite and Silver-Bearing Bornite in a Mixed Moderately Thermophilic Culture

    Directory of Open Access Journals (Sweden)

    Congren Yang

    2017-12-01

    Full Text Available Chalcopyrite and bornite are two important copper minerals, and they often coexist. In this study, the co-bioleaching of chalcopyrite and silver-bearing bornite by mixed moderately thermophilic culture at 50 °C was investigated. The bioleaching results show that the extraction percentage of Cu for co-bioleaching of chalcopyrite (Ccp and silver-bearing bornite (Bn (Ccp/Bn = 3:1 was 94.6%. Compared to bioleaching of chalcopyrite or silver-bearing bornite alone, the Cu extraction percentage was greatly enhanced when they were bioleached together. The leaching residues were characterized by X-ray diffraction (XRD and X-ray photoelectron spectroscopy (XPS. Silver-bearing bornite dissolved preferentially compared to chalcopyrite, due to galvanic interactions. Simultaneously, Ag+ was released from the silver-bearing bornite into solution. Ag2S formed on the surface because Cu and Fe in the chalcopyrite were replaced by Ag+, accelerating chalcopyrite dissolution and enrichment of Ag on the surface of the chalcopyrite.

  20. Mixed Wastewater Coupled with CO2 for Microalgae Culturing and Nutrient Removal.

    Directory of Open Access Journals (Sweden)

    Lili Yao

    Full Text Available Biomass, nutrient removal capacity, lipid productivity and morphological changes of Chlorella sorokiniana and Desmodesmus communis were investigated in mixed wastewaters with different CO2 concentrations. Under optimal condition, which was 1:3 ratio of swine wastewater to second treated municipal wastewater with 5% CO2, the maximum biomass concentrations were 1.22 g L-1 and 0.84 g L-1 for C. sorokiniana and D. communis, respectively. Almost all of the ammonia and phosphorus were removed, the removal rates of total nitrogen were 88.05% for C. sorokiniana and 83.18% for D. communis. Lipid content reached 17.04% for C. sorokiniana and 20.37% for D. communis after 10 days culture. CO2 aeration increased intracellular particle numbers of both microalgae and made D. communis tend to be solitary. The research suggested the aeration of CO2 improve the tolerance of microalgae to high concentration of NH4-N, and nutrient excess stress could induce lipid accumulation of microalgae.

  1. Transformation of trinitrotoluene to triaminotoluene by mixed cultures incubated under methanogenic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, P.; Chow, T.; Adrian, N.R.

    2000-04-01

    2,4,6-Trinitrotoluene (TNT) is an explosive widely used by the military. Although it is no longer manufactured in the US, large amounts of wastewater are generated annually from load, assembly, packing, and demilitarization operations. Granular-activated carbon adsorption is the standard technology for treating wastewater containing TNT and maintaining discharges within the limits established under the National Pollutant Discharge Elimination System. Studies evaluating biological treatment of pink water with an anaerobic fluidized-bed, granular-activated carbon bioreactor have been promising, but the fate of TNT is unknown. The authors investigated the anaerobic transformation of TNT by biofilm microorganisms obtained from a wastewater treatment plant receiving explosive manufacturing wastewater. The TNT was transformed to a mixture of 2-amino-4,6-dinitrotoluene; 4-amino-2,6-dinitrotoluene; 2,4-diamino-6-nitrotoluene; and 2,6-diamino-4-nitrotoluene before culminating in the formation of triaminotoluene (TAT). Triaminotoluene was susceptible to further degradation under anaerobic conditions, but its fate was not determined. Methane formation was inhibited but resumed after the depletion of the diaminonitrotoluene isomers. These studies demonstrate near stoichiometric formation of TAT from TNT and the transformation of 2-amino-4,6-dinitrotoluene to 2,4-diamino-6-nitrotoluene and 2,6-diamino-4-nitrotoluene by a mixed culture incubated under methanogenic conditions. This evidence indicates TAT is also a likely end-product of TNT biodegradation in the anaerobic fluidized fed bioreactor.

  2. Selective conversion of carbon monoxide to hydrogen by anaerobic mixed culture.

    Science.gov (United States)

    Liu, Yafeng; Wan, Jingjing; Han, Sheng; Zhang, Shicheng; Luo, Gang

    2016-02-01

    A new method for the conversion of CO to H2 was developed by anaerobic mixed culture in the current study. Higher CO consumption rate was obtained by anaerobic granular sludge (AGS) compared to waste activated sludge (WAS) at 55 °C and pH 7.5. However, H2 was the intermediate and CH4 was the final product. Fermentation at pH 5.5 by AGS inhibited CH4 production, while the lower CO consumption rate (50% of that at pH 7.5) and the production of acetate were found. Fermentation at pH 7.5 with the addition of chloroform achieved efficient and selective conversion of CO to H2. Stable and efficient H2 production was achieved in a continuous reactor inoculated with AGS, and gas recirculation was crucial to increase the CO conversion efficiency. Microbial community analysis showed that high abundance (44%) of unclassified sequences and low relative abundance (1%) of known CO-utilizing bacteria Desulfotomaculum were enriched in the reactor. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Characterization of mixed-culture biofilms established in microbial fuel cells

    International Nuclear Information System (INIS)

    Yang, Suling; Du, Fangzhou; Liu, Hong

    2012-01-01

    For the successful operation of a microbial fuel cell, it is important to characterize the biofilm on the anode. The behavior of MFCs during initial biofilm growth and characterization of anodic biofilm were studied using two-chamber MFCs with activated sludge as inoculum. After three times' replacement of the anodic growth medium, the biofilms were well developed, and a maximum closed circuit potential of 0.41 V and 0.37 V (1000 Ω resistor) was achieved using acetate and glucose, respectively. Electron microscopy revealed that there were rod-shaped cells 0.2–0.3 μm wide by 1.5–2.5 μm long in the anode biofilm in the acetate-fed MFC, and these cells were mainly arranged by monolayer. The biofilm in the glucose-fed MFC was made of cocci-shaped cells in chains and a thick matrix. Both using acetate and glucose, the anodic bacterial communities were different than those of the activated sludge. Cyclic voltammograms suggested that extracellular electron transfer in these MFCs was accomplished mainly by the biofilms on the anode and not by bacteria-produced mediators. -- Highlights: ► The mixed-culture biofilms established in MFCs were characterized. ► The possible electron transfer mechanism was presented. ► In these MFCs the anodic area should be much larger.

  4. Lactic acid production with undefined mixed culture fermentation of potato peel waste.

    Science.gov (United States)

    Liang, Shaobo; McDonald, Armando G; Coats, Erik R

    2014-11-01

    Potato peel waste (PPW) as zero value byproduct generated from food processing plant contains a large quantity of starch, non-starch polysaccharide, lignin, protein, and lipid. PPW as one promising carbon source can be managed and utilized to value added bioproducts through a simple fermentation process using undefined mixed cultures inoculated from wastewater treatment plant sludge. A series of non-pH controlled batch fermentations under different conditions such as pretreatment process, enzymatic hydrolysis, temperature, and solids loading were studied. Lactic acid (LA) was the major product, followed by acetic acid (AA) and ethanol under fermentation conditions without the presence of added hydrolytic enzymes. The maximum yields of LA, AA, and ethanol were respectively, 0.22 g g(-1), 0.06 g g(-1), and 0.05 g g(-1). The highest LA concentration of 14.7 g L(-1) was obtained from a bioreactor with initial solids loading of 60 g L(-1) at 35°C. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Oxidation of methane in biotrickling filters inoculated with methanotrophic bacteria.

    Science.gov (United States)

    Cáceres, Manuel; Dorado, Antonio D; Gentina, Juan C; Aroca, Germán

    2017-11-01

    The oxidation of methane (CH 4 ) using biofilters has been proposed as an alternative to mitigate anthropogenic greenhouse gas emissions with a low concentration of CH 4 that cannot be used as a source of energy. However, conventional biofilters utilize organic packing materials that have a short lifespan, clogging problems, and are commonly inoculated with non-specific microorganisms leading to unpredictable CH 4 elimination capacities (EC) and removal efficiencies (RE). The main objective of this work was to characterize the oxidation of CH 4 in two biotrickling filters (BTFs) packed with polyethylene rings and inoculated with two methanotrophic bacteria, Methylomicrobium album and Methylocystis sp., in order to determine EC and CO 2 production (pCO 2 ) when using a specific inoculum. The repeatability of the results in both BTFs was determined when they operated at the same inlet load of CH 4 . A dynamic mathematical model that describes the CH 4 abatement in the BTFs was developed and validated using mass transfer and kinetic parameters estimated independently. The results showed that EC and pCO 2 of the BTFs are not identical but very similar for all the conditions tested. The use of specific inoculum has shown a faster startup and higher EC per unit area (0.019 gCH 4  m -2  h -1 ) in comparison to most of the previous studies at the same CH 4 load rate (23.2 gCH 4  m -3  h -1 ). Global mass balance showed that the maximum reduction of CO 2 equivalents was 98.5 gCO 2eq  m -3  h -1 . The developed model satisfactorily described CH 4 abatement in BTFs for a wide range of conditions.

  6. Oxygen Limited Bioreactors System For Nitrogen Removal Using Immobilized Mix Culture

    Science.gov (United States)

    Pathak, B. K.; Sumino, T.; Saiki, Y.; Kazama, F.

    2005-12-01

    Recently nutrients concentrations especially nitrogen in natural water is alarming in the world wide. Most of the effort is being done on the removal of high concentration of nitrogen especially from the wastewater treatment plants. The removal efficiency is targeted in all considering the effluent discharge standard set by the national environment agency. In many cases, it does not meet the required standard and receiving water is being polluted. Eutrophication in natural water bodies has been reported even if the nitrogen concentration is low and self purification of natural systems itself is not sufficient to remove the nitrogen due to complex phenomenon. In order to recover the pristine water environment, it is very essential to explore bioreactor systems for natural water systems using immobilized mix culture. Microorganism were entrapped in Polyethylene glycol (PEG) prepolymer gel and cut into 3mm cubic immobilized pellets. Four laboratory scale micro bio-reactors having 0.1 L volumes were packed with immobilized pellets with 50% compact ratio. RUN1, RUN2, RUN3 and RUN4 were packed with immobilized pellets from reservoirs sediments, activated sludge (AS), mixed of AS, AG and biodegradable plastic and anaerobic granules (AG) respectively. Water from Shiokawa Reservoirs was feed to all reactors with supplemental ammonia and nitrite nitrogen as specified in the results and discussions. The reactors were operated dark incubated room in continuous flow mode with hydraulic retention time of 12 hours under oxygen limiting condition. Ammonium, nitrate nitrite nitrogen and total organic carbon (TOC) concentrations were measured as described in APWA and AWWA (1998). Laboratory scale four bioreactors containing different combination of immobilized cell were monitored for 218 days. Influent NH4+-N and NO2--N concentration were 2.27±0.43 and 2.05±0.41 mg/l respectively. Average dissolved oxygen concentration and pH in the reactors were 0.40-2.5 mg/l and pH 6

  7. Bacteria that degrade hazardous waste: The isolation of trichloroethylene-degrading methanotrophic bacteria and development of monoclonal antibodies specific to them

    International Nuclear Information System (INIS)

    Little, C.D.

    1988-01-01

    Trichloroethylene (TCE), a suspected carcinogen, is one of the most frequently reported groundwater contaminants at hazardous waste sites in the US. An aerobic, methane-oxidizing bacterium was isolated that degrades TCE in pure culture at concentrations commonly observed in contaminated groundwater. Strain 46-1, a Type I methanotrophic bacterium, degraded TCE when growing on methane or methanol, producing CO 2 and water-soluble products. Gas chromatography and 14 C radiotracer techniques were used to determine the rate, methane dependence, and mechanism of TCE biodegradation. TCE biodegradation by strain 46-1 appears to be a co-metabolic process that occurs when the organism is actively metabolizing a suitable growth substrate such as methane or methanol. Five mouse monoclonal antibodies (MABS) that specifically bind strain 46-1 were prepared by conventional hybridoma technology. These MABS are apparently biochemically distinct and were used to develop enzyme-linked and fluorescent immunoassays to detect strain 46-1 cells in environmental samples. A fluorescent immunoassay utilizing four of these MABS easily distinguished laboratory-grown 46-1 cells from other methanotrophic and heterotrophic bacteria, but failed to detect 46-1 cells in groundwater samples and cultures

  8. Biodegradation of ortho-Cresol by a Mixed Culture of Nitrate-Reducing Bacteria Growing On Toluene

    DEFF Research Database (Denmark)

    Flyvbjerg, John; Jørgensen, Claus; Arvin, Erik

    1993-01-01

    A mixed culture of nitrate-reducing bacteria degraded o-cresol in the presence of toluene as a primary growth substrate. No degradation of o-cresol was observed in the absence of toluene or when the culture grew on p-cresol and 2,4-dimethylphenol. In batch cultures, the degradation of o-cresol st......A mixed culture of nitrate-reducing bacteria degraded o-cresol in the presence of toluene as a primary growth substrate. No degradation of o-cresol was observed in the absence of toluene or when the culture grew on p-cresol and 2,4-dimethylphenol. In batch cultures, the degradation of o...... of toluene metabolized, with an average yield of 0.47 mg of o-cresol degraded per mg of toluene metabolized. Experiments with (ring-U-14C)o-cresol indicated that about 73% of the carbon from degraded o-cresol was mineralized to CO-2 and about 23% was assimilated into biomass after the transient accumulation...

  9. An adjustable gas-mixing device to increase feasibility of in vitro culture of Plasmodium falciparum parasites in the field.

    Directory of Open Access Journals (Sweden)

    Amy K Bei

    Full Text Available A challenge to conducting high-impact and reproducible studies of the mechanisms of P. falciparum drug resistance, invasion, virulence, and immunity is the lack of robust and sustainable in vitro culture in the field. While the technology exists and is routinely utilized in developed countries, various factors-from cost, to supply, to quality-make it hard to implement in malaria endemic countries. Here, we design and rigorously evaluate an adjustable gas-mixing device for the in vitro culture of P. falciparum parasites in the field to circumvent this challenge. The device accurately replicates the gas concentrations needed to culture laboratory isolates, short-term adapted field isolates, cryopreserved previously non-adapted isolates, as well as to adapt ex vivo isolates to in vitro culture in the field. We also show an advantage over existing alternatives both in cost and in supply. Furthermore, the adjustable nature of the device makes it an ideal tool for many applications in which varied gas concentrations could be critical to culture success. This adjustable gas-mixing device will dramatically improve the feasibility of in vitro culture of Plasmodium falciparum parasites in malaria endemic countries given its numerous advantages.

  10. Fermentative hydrogen production by Clostridium butyricum CWBI1009 and Citrobacter freundii CWBI952 in pure and mixed cultures

    Directory of Open Access Journals (Sweden)

    Beckers, L.

    2010-01-01

    Full Text Available This paper investigates the biohydrogen production by two mesophilic strains, a strict anaerobe (Clostridium butyricum CWBI1009 and a facultative anaerobe (Citrobacter freundii CWBI952. They were cultured in pure and mixed cultures in serum bottles with five different carbon sources. The hydrogen yields of pure C. freundii cultures ranged from 0.09 molH2.molhexose-1 (with sucrose to 0.24 molH2.molhexose-1 (with glucose. Higher yields were obtained by the pure cultures of Cl. butyricum ranging from 0.44 molH2.molhexose-1 (with sucrose to 0.69 molH2.molhexose-1 (with lactose. This strain also fermented starch whereas C. freundii did not. However, it consumed the other substrates faster and produced hydrogen earlier than Cl. butyricum. This ability has been used to promote the growth conditions of Cl. butyricum in co-culture with C. freundii, since Cl. butyricum is extremely sensitive to the presence of oxygen which strongly inhibits H2 production. This approach could avoid the addition of any expensive reducing agents in the culture media such as L-cysteine since C. freundii consumes the residual oxygen. Thereafter, co-cultures with glucose and starch were investigated: hydrogen yields decreased from 0.53 molH2.molhexose-1 for pure Cl. butyricum cultures to 0.38 molH2.molhexose-1 for mixed culture with glucose but slightly increased with starch (respectively 0.69 and 0.73 molH2.molhexose-1. After 48 h of fermentation, metabolites analysis confirmed with microbial observation, revealed that the cell concentration of C. freundii dramatically decreased or was strongly inhibited by the development of Cl. butyricum.

  11. Changing Perspectives: Validation Framework Review of Examples of Mixed Methods Research into Culturally Relevant Teaching

    Science.gov (United States)

    Hales, Patrick Dean

    2016-01-01

    Mixed methods research becomes more utilized in education research every year. As this pluralist paradigm begins to take hold, it becomes more and more necessary to take a critical eye to studies making use of different mixed methods approaches. An area of education research that has yet struggled to find a foothold with mixed methodology is…

  12. Rhizospheric salt tolerant bacteria improving plant growth in single and mixed culture inoculations under NaCl stress (abstract)

    International Nuclear Information System (INIS)

    Afrasayab, S.; Hasnain, S.

    2005-01-01

    Salt tolerant bacterial strains isolated from rhizosphere of Mazus plant (inhabitant of salt range) were used singly (ST -1; ST -2; ST -3; ST -4) and in mixed combinations (ST -1,3,4; ST -2,3,4) to improve the growth to Tricticum aestivum in the pot experiments. Growth and yield of T. aestivum var. Inqlab-91 plants exposed to NaCl stress (0.75% NaCl) was markedly affected. Na/sup +//K/sup +/ ratios in shoots and roots were profoundly increased under NaCl stress. Bacterial inoculations improved plant growth under salt stress. Bacterial combinations ST - 1,3,4 and ST -2,3,4 were more effective in stimulating growth and showed prominent results as compared to their pure cultures. Mono and mixed bacterial inoculations improved yield parameters of wheat. ST -1,3,4 mixed culture inoculation maximally improved yield under salt stress. Generally bacterial inoculations resulted in increase in Na/sup +//K/sup +/ ratios in shoots and roots under salt free and salt stress conditions. Overall ST -1,3,4 mixed inoculation yielded promising results under NaCl stress, hence 168 rRNA gene sequence analysis of its pure cultures was obtained for their identification to genus level. (author)

  13. Effects of sole and mixed culture of wheat crop and phosphorus fertilization on the solubility of phosphorus in the soil

    International Nuclear Information System (INIS)

    Mahmood, H. R.; Ali, M. A.; Ahmad, N.

    2016-01-01

    Farmers face a challenging task to harvest yield potential of crops as well as improving fertilizer use-efficiency under their limited farm resources. Among the macronutrients, the relative efficiency of phosphorus fertilizer is very low in alkaline-calcareous soils under arid and semi-arid environments. Therefore, a field study was undertaken to quantify the interactive effects of wheat varieties and phosphorous fertilization on grain yield and solubility of phosphorous nutrient in the rhizosphere. The treatments consisted of (a) two wheat varieties (Sehr-2006, Shafaq-2006, mixed culture) and (b) three phosphorus levels (0, 45, 85 kg P/sub 2/O/sub 5/ per hectare) were arranged in randomized complete block design and replicated four times. The Results showed that biological grain yield and 1000-grain weight of wheat increased by 8.7 percent, 14.46 percent and 8.48 percent under mixed culture of varieties sehr-2006 and shafaq-2006, respectively over the solely grown varieties. The application of phosphorus at the rate 85 kg P/sub 2/O/sub 5/ ha/sup -1/ resulted in increased quantity of total biological yield, grain yield and 1000-grain weight compared to unfertilized crop. The uptake of nitrogen and phosphorus contents were substantially enhanced under mixed culture cropping pattern over sole wheat cultivars. The availability of phosphorus was increased by 19.70 percent under mixed cropping over sole culture. It is inferred from the study that mixed cropping produced synergetic effects on the availability of nutrients in the rhizosphere, and thereby resulted in the higher production of wheat crop. (author)

  14. Functional redundancy ensures performance robustness in 3-stage PHA-producing mixed cultures under variable feed operation.

    Science.gov (United States)

    Carvalho, Gilda; Pedras, Inês; Karst, Soren M; Oliveira, Catarina S S; Duque, Anouk F; Nielsen, Per H; Reis, Maria A M

    2018-01-25

    Polyhydroxyalkanoates (PHA) are biopolymers that can be produced by mixed microbial cultures using wastes or industrial by-products, which represent an economical and environmental advantage over pure culture processes. The use of alternate feedstocks enables using seasonal by-products, providing that the process is resilient to transient conditions. The mixed microbial communities of a 3-stage PHA producing system fed initially with molasses and then cheese whey were investigated through amplicon sequencing of the 16S rRNA gene. The transition in feedstock resulted in an adaptation of the acidogenic community, where Actinobacteria dominated with sugarcane molasses (up to 93% of the operational taxonomic units) and Firmicutes, with cheese whey (up to 97%). The resulting fermentation products profile also changed, with a higher fraction of HV precursors obtained with molasses than cheese whey (7.1±0.5 and 1.7±0.7 gCOD/L, respectively). As for the PHA storing culture, the genera Azoarcus, Thauera and Paracoccus were enriched with fermented molasses (average 89% of Bacteria). Later, fermented cheese whey fostered a higher diversity, including some less characterised PHA-storers such as the genera Paenibacillus and Lysinibacillus. Although the microbial community structure was significantly affected by the feedstock shift, the acidogenic and PHA storing performance of the 3-stage system was very similar once a pseudo steady state was attained, showing that a reliable level of functional redundancy was attained in both mixed cultures. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. The conversion of BTEX compounds by single and defined mixed cultures to medium-chain-length polyhydroxyalkanoate.

    Science.gov (United States)

    Nikodinovic, Jasmina; Kenny, Shane T; Babu, Ramesh P; Woods, Trevor; Blau, Werner J; O'Connor, Kevin E

    2008-09-01

    Here, we report the use of petrochemical aromatic hydrocarbons as a feedstock for the biotechnological conversion into valuable biodegradable plastic polymers--polyhydroxyalkanoates (PHAs). We assessed the ability of the known Pseudomonas putida species that are able to utilize benzene, toluene, ethylbenzene, p-xylene (BTEX) compounds as a sole carbon and energy source for their ability to produce PHA from the single substrates. P. putida F1 is able to accumulate medium-chain-length (mcl) PHA when supplied with toluene, benzene, or ethylbenzene. P. putida mt-2 accumulates mcl-PHA when supplied with toluene or p-xylene. The highest level of PHA accumulated by cultures in shake flask was 26% cell dry weight for P. putida mt-2 supplied with p-xylene. A synthetic mixture of benzene, toluene, ethylbenzene, p-xylene, and styrene (BTEXS) which mimics the aromatic fraction of mixed plastic pyrolysis oil was supplied to a defined mixed culture of P. putida F1, mt-2, and CA-3 in the shake flasks and fermentation experiments. PHA was accumulated to 24% and to 36% of the cell dry weight of the shake flask and fermentation grown cultures respectively. In addition a three-fold higher cell density was achieved with the mixed culture grown in the bioreactor compared to shake flask experiments. A run in the 5-l fermentor resulted in the utilization of 59.6 g (67.5 ml) of the BTEXS mixture and the production of 6 g of mcl-PHA. The monomer composition of PHA accumulated by the mixed culture was the same as that accumulated by single strains supplied with single substrates with 3-hydroxydecanoic acid occurring as the predominant monomer. The purified polymer was partially crystalline with an average molecular weight of 86.9 kDa. It has a thermal degradation temperature of 350 degrees C and a glass transition temperature of -48.5 degrees C.

  16. The relationship between organizational culture and the health and wellbeing of hospital nurses worldwide: a mixed methods systematic review protocol.

    Science.gov (United States)

    Whitcombe, Anne; Cooper, Kay; Palmer, Emma

    2016-06-01

    The objective of this mixed methods systematic review is to examine the relationship between organizational culture and the health and wellbeing of hospital nurses, and to develop an aggregated synthesis of quantitative and qualitative systematic reviews to derive recommendations for policy and practice.Organizational culture comprises factors such as leadership, management and support, a health and safety oriented workplace climate and job characteristics.The quantitative component of this review will explore the relationship between organizational culture and the following outcomes in hospital nurses which may be indicators of health and wellbeing: work-related injury such as needlestick or sharp injuries, musculoskeletal injuries and conditions such as low back pain, burnout and general wellbeing.The qualitative component of this review will explore the perceptions of hospital nurses in relation to the impact of organizational culture on their own health and wellbeing and those of their nursing colleagues.

  17. Niche differentiation in nitrogen metabolism among methanotrophs within an operational taxonomic unit.

    Science.gov (United States)

    Hoefman, Sven; van der Ha, David; Boon, Nico; Vandamme, Peter; De Vos, Paul; Heylen, Kim

    2014-04-04

    The currently accepted thesis on nitrogenous fertilizer additions on methane oxidation activity assumes niche partitioning among methanotrophic species, with activity responses to changes in nitrogen content being dependent on the in situ methanotrophic community structure Unfortunately, widely applied tools for microbial community assessment only have a limited phylogenetic resolution mostly restricted to genus level diversity, and not to species level as often mistakenly assumed. As a consequence, intragenus or intraspecies metabolic versatility in nitrogen metabolism was never evaluated nor considered among methanotrophic bacteria as a source of differential responses of methane oxidation to nitrogen amendments. We demonstrated that fourteen genotypically different Methylomonas strains, thus distinct below the level at which most techniques assign operational taxonomic units (OTU), show a versatile physiology in their nitrogen metabolism. Differential responses, even among strains with identical 16S rRNA or pmoA gene sequences, were observed for production of nitrite and nitrous oxide from nitrate or ammonium, nitrogen fixation and tolerance to high levels of ammonium, nitrate, and hydroxylamine. Overall, reduction of nitrate to nitrite, nitrogen fixation, higher tolerance to ammonium than nitrate and tolerance and assimilation of nitrite were general features. Differential responses among closely related methanotrophic strains to overcome inhibition and toxicity from high nitrogen loads and assimilation of various nitrogen sources yield competitive fitness advantages to individual methane-oxidizing bacteria. Our observations proved that community structure at the deepest phylogenetic resolution potentially influences in situ functioning.

  18. Draft Genome Sequence of Methylocella silvestris TVC, a Facultative Methanotroph Isolated from Permafrost

    OpenAIRE

    Wang, Jing; Geng, Kan; Farhan Ul Haque, Muhammad; Crombie, Andrew; Street, Lorna E.; Wookey, Philip A.; Ma, Ke; Murrell, J. Colin; Pratscher, Jennifer

    2018-01-01

    Permafrost environments play a crucial role in global carbon and methane cycling. We report here the draft genome sequence of Methylocella silvestris TVC, a new facultative methanotroph strain, isolated from the Siksik Creek catchment in the continuous permafrost zone of Inuvik (Northwest Territories, Canada).

  19. Draft Genome Sequence of Methylocella silvestris TVC, a Facultative Methanotroph Isolated from Permafrost.

    Science.gov (United States)

    Wang, Jing; Geng, Kan; Farhan Ul Haque, Muhammad; Crombie, Andrew; Street, Lorna E; Wookey, Philip A; Ma, Ke; Murrell, J Colin; Pratscher, Jennifer

    2018-02-22

    Permafrost environments play a crucial role in global carbon and methane cycling. We report here the draft genome sequence of Methylocella silvestris TVC, a new facultative methanotroph strain, isolated from the Siksik Creek catchment in the continuous permafrost zone of Inuvik (Northwest Territories, Canada). Copyright © 2018 Wang et al.

  20. Aerobic methanotrophic communities at the Red Sea brine-seawater interface

    KAUST Repository

    Abdallah, Rehab Z.

    2014-09-23

    Abdallah RZ, Adel M, Ouf A, Sayed A, Ghazy MA, Alam I, Essack M, Lafi FF, Bajic VB, El-Dorry H and Siam R (2014) Aerobic methanotrophic communities at the Red Sea brine-seawater interface. Front. Microbiol. 5:487. doi: 10.3389/fmicb.2014.00487

  1. Methanotrophic community dynamics in a seasonally anoxic fjord: Saanich Inlet, British Columbia

    Directory of Open Access Journals (Sweden)

    Mónica Torres-Beltrán

    2016-12-01

    Full Text Available Marine oxygen minimum zones (OMZs play disproportionate roles in nutrient and climate active trace gas cycling including nitrous oxide and methane, in the ocean. OMZs are currently expanding due to climate change making it increasingly important to identify microbial controls on trace gas cycling at the individual, population and community levels. Here we present a two-year survey of the microbial community along seasonal redox gradients in Saanich Inlet focused on identifying microbial agents driving methane oxidation. Although methanotrophs were rare, we identified three uncultivated groups affiliated with particulate methane monooxygenase (pMMO encoding phylogenetic groups (OPU, and methanotrophic symbionts as primary drivers of methane oxidation in Saanich Inlet. Distribution and activity patterns for these three groups were consistent with niche partitioning that became increasingly resolved during water column stratification. Moreover co-occurrence analysis combined with multi-level indicator species analysis revealed significant correlations between operational taxonomic units affiliated with Methylophaga, Methylophilales, SAR324, Verrucomicrobia, and Planctomycetes with OPUs and methanotrophic symbiont groups. Taken together these observations shed new light on the composition, dynamics, and potential interspecific interactions of microbes associated with CH4 cycling in the Saanich Inlet water column, provide a baseline for comparison between coastal and open ocean OMZs and support the potential role of OPUs, and methanotrophic symbiont groups as a widely distributed pelagic sink for CH4 along continental margins.

  2. Ammonium addition inhibits 13C-methane incorporation into methanotroph membrane lipids in a freshwater sediment

    NARCIS (Netherlands)

    Nold, s.c.; Boschker, H.T.S.; Pel, R.; Laanbroek, H.J.

    1999-01-01

    To investigate the effect of ammonium addition on the species composition and activity of freshwater methane oxidizing bacteria, intact sediment cores were labeled with (CH4)-C-13 and incubated under ambient and elevated ammonium concentrations. After 7 days, methanotroph activity was assessed by

  3. Ammonium addition inhibits 13C-methane incorporation into methanotroph membrane lipids in a freshwater sediment

    NARCIS (Netherlands)

    Nold, S.C.; Boschker, H.T.S.; Pel, R.; Laanbroek, H.J.

    1999-01-01

    To investigate the effect of ammonium addition on the species composition and activity of freshwater methane oxidizing bacteria, intact sediment cores were labeled with 13CH4 and incubated under ambient and elevated ammonium concentrations. After 7 days, methanotroph activity was assessed by

  4. Intracellular PHB conversion in a type II methanotroph studied by 13 C NMR

    NARCIS (Netherlands)

    Vecherskaya, M.; Dijkema, C.; Stams, A.J.M.

    2001-01-01

    Poly-g-hydroxybutyrate (PHB) formation under aerobic conditions via incorporation of [13C-2]acetate as a cosubstrate and its intracellular degradation under anaerobic conditions in a Type II methanotroph was studied by 13C NMR. During PHB synthesis in the presence of labelled acetate, low levels of

  5. Environmental evidence for net methane production and oxidation in putative ANaerobic MEthanotrophic (ANME) archaea

    DEFF Research Database (Denmark)

    Lloyd, Karen; Teske, Andreas; Alperin, Marc J.

    2011-01-01

    . Anaerobic methane oxidation regulates methane emissions in marine sediments and appears to occur through a reversal of a methane-producing metabolism. We tested the assumption that ANME are obligate methanotrophs by detecting and quantifying gene transcription of ANME-1 across zones of methane oxidation...

  6. Family- and genus-level 16S rRNA-targeted oligonucleotide probes for ecological studies of methanotrophic bacteria.

    Science.gov (United States)

    Gulledge, J; Ahmad, A; Steudler, P A; Pomerantz, W J; Cavanaugh, C M

    2001-10-01

    Methanotrophic bacteria play a major role in the global carbon cycle, degrade xenobiotic pollutants, and have the potential for a variety of biotechnological applications. To facilitate ecological studies of these important organisms, we developed a suite of oligonucleotide probes for quantitative analysis of methanotroph-specific 16S rRNA from environmental samples. Two probes target methanotrophs in the family Methylocystaceae (type II methanotrophs) as a group. No oligonucleotide signatures that distinguish between the two genera in this family, Methylocystis and Methylosinus, were identified. Two other probes target, as a single group, a majority of the known methanotrophs belonging to the family Methylococcaceae (type I/X methanotrophs). The remaining probes target members of individual genera of the Methylococcaceae, including Methylobacter, Methylomonas, Methylomicrobium, Methylococcus, and Methylocaldum. One of the family-level probes also covers all methanotrophic endosymbionts of marine mollusks for which 16S rRNA sequences have been published. The two known species of the newly described genus Methylosarcina gen. nov. are covered by a probe that otherwise targets only members of the closely related genus Methylomicrobium. None of the probes covers strains of the newly proposed genera Methylocella and "Methylothermus," which are polyphyletic with respect to the recognized methanotrophic families. Empirically determined midpoint dissociation temperatures were 49 to 57 degrees C for all probes. In dot blot screening against RNA from positive- and negative-control strains, the probes were specific to their intended targets. The broad coverage and high degree of specificity of this new suite of probes will provide more detailed, quantitative information about the community structure of methanotrophs in environmental samples than was previously available.

  7. Analysis of microbial community variation during the mixed culture fermentation of agricultural peel wastes to produce lactic acid.

    Science.gov (United States)

    Liang, Shaobo; Gliniewicz, Karol; Gerritsen, Alida T; McDonald, Armando G

    2016-05-01

    Mixed cultures fermentation can be used to convert organic wastes into various chemicals and fuels. This study examined the fermentation performance of four batch reactors fed with different agricultural (orange, banana, and potato (mechanical and steam)) peel wastes using mixed cultures, and monitored the interval variation of reactor microbial communities with 16S rRNA genes using Illumina sequencing. All four reactors produced similar chemical profile with lactic acid (LA) as dominant compound. Acetic acid and ethanol were also observed with small fractions. The Illumina sequencing results revealed the diversity of microbial community decreased during fermentation and a community of largely lactic acid producing bacteria dominated by species of Lactobacillus developed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Finding Balance in a Mix of Culture: Appreciation of Diversity through Multicultural Music Education

    Science.gov (United States)

    Nethsinghe, Rohan

    2012-01-01

    This study explores the understandings of cultural diversity as enacted in multicultural music education and is located in Victoria, which is identified as the most culturally diverse state in Australia with a population that comes from various countries and speaks many languages. This cultural diversity is reflected in the schools. This…

  9. Stable acetate production in extreme-thermophilic (70°C) mixed culture fermentation by selective enrichment of hydrogenotrophic methanogens

    Science.gov (United States)

    Zhang, Fang; Zhang, Yan; Ding, Jing; Dai, Kun; van Loosdrecht, Mark C. M.; Zeng, Raymond J.

    2014-06-01

    The control of metabolite production is difficult in mixed culture fermentation. This is particularly related to hydrogen inhibition. In this work, hydrogenotrophic methanogens were selectively enriched to reduce the hydrogen partial pressure and to realize efficient acetate production in extreme-thermophilic (70°C) mixed culture fermentation. The continuous stirred tank reactor (CSTR) was stable operated during 100 days, in which acetate accounted for more than 90% of metabolites in liquid solutions. The yields of acetate, methane and biomass in CSTR were 1.5 +/- 0.06, 1.0 +/- 0.13 and 0.4 +/- 0.05 mol/mol glucose, respectively, close to the theoretical expected values. The CSTR effluent was stable and no further conversion occurred when incubated for 14 days in a batch reactor. In fed-batch experiments, acetate could be produced up to 34.4 g/L, significantly higher than observed in common hydrogen producing fermentations. Acetate also accounted for more than 90% of soluble products formed in these fed-batch fermentations. The microbial community analysis revealed hydrogenotrophic methanogens (mainly Methanothermobacter thermautotrophicus and Methanobacterium thermoaggregans) as 98% of Archaea, confirming that high temperature will select hydrogenotrophic methanogens over aceticlastic methanogens effectively. This work demonstrated a potential application to effectively produce acetate as a value chemical and methane as an energy gas together via mixed culture fermentation.

  10. Cosmeceutical potentials and bioactive compounds of rice bran fermented with single and mix culture of Aspergillus oryzae and Rhizopus oryzae

    Directory of Open Access Journals (Sweden)

    Dang Lelamurni Abd Razak

    2017-04-01

    Full Text Available In the present study, rice bran, one of the most abundant agricultural by-products in Malaysia, was fermented with single and mixed cultures of Aspergillus oryzae and Rhizopus oryzae. The fermented rice bran extracts were tested for their functional properties and compared to the non-fermented counterparts. Antioxidant activities as well as phenolics and organic acid contents were evaluated. Skincare-related functionalities were also tested by evaluating tyrosinase and elastase inhibition activities. Tyrosinase inhibition activity, measured to determine the anti-pigmentation effect of extracts, was found to be the highest in the extract of rice bran fermented with A. oryzae (56.18% compared to other extracts. In determining the anti-aging effect of fermented rice bran extracts, the same extract showed the highest elastase inhibition activity with a value of 60.52%. Antioxidant activities were found to be highest in the mix-cultured rice bran extract. The results of phenolic and organic acid content were varied; the major phenolic acid detected was ferulic acid with a value of 43.19 μg/ml in the mix-cultured rice bran extract. On the other hand, citric acid was the major organic acid detected, with the highest content found in the same extract (214.6 mg/g. The results of this study suggest that the fermented rice bran extracts may have the potential to be further exploited as ingredients in cosmetics as well as in antioxidant-rich products.

  11. Test Plan for Methanotrophic Bioreactor at Savannah River Site-TNX

    International Nuclear Information System (INIS)

    Berry, C.J.

    1994-01-01

    The primary purpose of this project is to demonstrate the feasibility and practicality of operating a methanotrophic mobile trickle filter bioreactor (MMB) unit to effectively reduce or eliminate trichloroethylene (TCE) and associated hydrocarbons from contaminated groundwater. The two-column trickle filter system can process 1.67 gallons per minute (gpm) of contaminated groundwater. During this project, the pilot system will evaluate, optimize, and demonstrate methanotrophic treatment technology (MTT). The mobile system will receive a 1--4% methane to air mixture for stimulating the methanotrophic TCE degrading bacteria, thereby increasing the rates of degradation of these contaminants. This project will also evaluate the efficacy of different bacteria for degrading TCE for use in the system at the laboratory-scale sample groundwater monitoring wells at TNX and set up the system for continued operation. The trickle filter system may be used to inexpensively treat other small-scale organic waste streams at SRS after the initial start-up. The MTT was demonstrated as an effective and efficient method of degrading TCE in the laboratory and during a field-scale in situ demonstration for degrading TCE in a groundwater plume at SRS. The methanotrophic bacteria increase significantly in population numbers and in the production of methane monooxygenase (MMO), an extremely powerful oxidizer. MMO was demonstrated as effective in oxidizing TCE and other recalcitrant compounds in laboratory studies. In the presence of MMO, TCE is oxidized to TCE-epoxide, which breaks down spontaneously into simple, easily degraded, daughter compounds. The system will receive a 1--4% methane to air mixture, which will effectively grow and maintain the methanotrophic bacteria that will degrade TCE. This demonstration will have broad applications to bioremediating contaminated groundwater systems where in situ bioremediation is not practical

  12. Impact of nitrogen feeding regulation on polyhydroxyalkanoates production by mixed microbial cultures.

    Science.gov (United States)

    Silva, Fernando; Campanari, Sabrina; Matteo, Stefania; Valentino, Francesco; Majone, Mauro; Villano, Marianna

    2017-07-25

    A sequencing batch reactor (SBR) is typically used for selecting mixed microbial cultures (MMC) for polyhydroxyalkanoate (PHA) production. Since many waste streams suitable as process feedstock for PHA production are nitrogen-deficient, a nutrient supply in the SBR is typically required to allow for efficient microbial growth. The scope of this study was to devise a nitrogen feeding strategy which allows controlling the nitrogen levels during the feast and famine regime of a lab-scale SBR, thereby selecting for PHA-storing microorganisms. At the beginning of the cycle the reactor was fed with a synthetic mixture of acetic and propionic acids at an overall organic load rate of 8.5gCODL -1 d -1 (i.e. 260CmmolL -1 d -1 ), whereas nitrogen (in the form of ammonium sulphate) was added either simultaneously to the carbon feed (coupled feeding strategy) or after the end of the feast phase (uncoupled feeding strategy). As a main result, PHA production was more than doubled (up to about 1300±64mgCODL -1 ) when carbon and nitrogen were separately fed and the higher PHA production also corresponded to an 82% increase in the polymer HV content (up to 20±1%, wtwt -1 ). Three SBR runs were performed with the uncoupled carbon and nitrogen feeding at different carbon to nitrogen (C/N) ratios (of 14.3, 17.9, and 22.3CmolNmol -1 , respectively) which were varied by progressively reducing the concentration of the nitrogen feeding. In spite of a comparable PHA storage yield at 14.3 and 17.9CmolNmol -1 (0.41±0.05 gCOD PHA gCOD VFA -1 and 0.38±0.05 gCOD PHA gCOD VFA -1 , respectively), the storage response of the selected MMC significantly decreased when the C/N ratio was set at the highest investigated value. Notably, an increase in this parameter also resulted in a change in the HV content in the polymer regardless the composition of the organic acids solution. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Fermentative capabilities and volatile compounds produced by Kloeckera/Hanseniaspora and Saccharomyces yeast strains in pure and mixed cultures during Agave tequilana juice fermentation.

    Science.gov (United States)

    González-Robles, Ivonne Wendolyne; Estarrón-Espinosa, Mirna; Díaz-Montaño, Dulce María

    2015-09-01

    The fermentative and aromatic capabilities of Kloeckera africana/Hanseniaspora vineae K1, K. apiculata/H. uvarum K2, and Saccharomyces cerevisiae S1 and S2 were studied in pure and mixed culture fermentations using Agave tequila juice as the culture medium. In pure and mixed cultures, Kloeckera/Hanseniaspora strains showed limited growth and sugar consumption, as well as low ethanol yield and productivity, compared to S. cerevisiae, which yielded more biomass, ethanol and viable cell concentrations. In pure and mixed cultures, S. cerevisiae presented a similar behaviour reaching high biomass production, completely consuming the sugar, leading to high ethanol production. Furthermore, the presence of S. cerevisiae strains in the mixed cultures promoted the production of higher alcohols, acetaldehyde and ethyl esters, whereas Kloeckera/Hanseniaspora strains stimulated the production of ethyl acetate and 2-phenyl ethyl acetate compounds.

  14. Financial abuse in elderly Korean immigrants: mixed analysis of the role of culture on perception and help-seeking intention.

    Science.gov (United States)

    Lee, Hee Yun; Eaton, Charissa K

    2009-07-01

    This study aims to evaluate how elderly Korean immigrants perceive and respond to a hypothetical incident of financial abuse on the basis of their cultural background. By using a quota sampling strategy, 124 elderly Korean immigrants were recruited. A mixed-method approach was employed to explore the role of culture on elderly immigrants' view of financial abuse and the construct of independent and interdependent self-construal was adopted to theoretically guide the study. Mixed-method analysis confirmed considerable influence of culture, particularly in responding to the abusive situation. Although the vast majority of the elders (92%) perceived financial abuse as elder mistreatment, only two-thirds (64%) intended to seek help. Five major themes for not seeking help were produced. These are: (a) issues related to family problems, (b) tolerance of the abuse, (c) shame, (d) victim blame, and (e) mistrust toward third party intervention. A series of binary logistic regressions revealed (a) a lower likelihood of seeking formal types of help with those who had higher level of adherence to traditional values and (b) the profile of vulnerable elderly Koreans who are at higher risk of being financially abused: male and less educated. This article also discusses implications for social work practice and elder mistreatment policy, particularly focusing on how to work with elderly Korean immigrants who are vulnerable to this problem and who tend to use collectivistic cultural values in responding to financial abuse.

  15. Effect of changing temperature on anaerobic hydrogen production and microbial community composition in an open-mixed culture bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Karadag, Dogan; Puhakka, Jaakko A. [Department of Chemistry and Bioengineering, Tampere University of Technology, Tampere (Finland)

    2010-10-15

    The temperature effect (37-65 C) on H{sub 2} production from glucose in an open-mixed culture bioreactor using an enrichment culture from a hot spring was studied. The dynamics of microbial communities was investigated by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). At 45 and 60 C the H{sub 2} production was the highest i.e. 1.71 and 0.85 mol H{sub 2}/mol glucose, respectively. No H{sub 2} was produced at temperatures 50 and 55 C. At 37-45 C, H{sub 2} production was produced by butyrate type fermentation while fermentation mechanism changed to ethanol type at 60 C. Clostridium species were dominant at 37-45 C while at 50-55 C and 60 C the culture was dominated by Bacillus coagulans and Thermoanaerobacterium, respectively. In the presence of B. Coagulans the metabolism was directed to lactate production. The results show that the mixed culture had two optima for H{sub 2} production and that the microbial communities and metabolic patterns promptly changed according to changing temperatures. (author)

  16. Marked heterogeneity in growth characteristics of myoblast clonal cultures and myoblast mixed cultures obtained from the same individual

    NARCIS (Netherlands)

    Maier, Andrea B.; Cohen, Ron; Blom, Joke; Van Heemst, Diana; Westendorp, Rudi G.J.

    Background: Sarcopenia is defined as an age-related decrease in skeletal muscle mass and function while adjacent satellite cells are unable to compensate for this loss. However, myoblast cultures can be established even in the presence of sarcopenia. Objective: It is yet unknown whether satellite

  17. Cellulose decomposition and associated nitrogen fixation by mixed cultures of Cellulomonas gelida and Azospirillum species or Bacillus macerans

    Energy Technology Data Exchange (ETDEWEB)

    Halsall, D.M.; Gibson, A.H.

    1985-10-01

    Mixed cultures of Cellulomonas gelida plus Azospirillum lipoferum or Azospirillum brasilense and C. gelida plus Bacillus macerans were shown to degrade cellulose and straw and to utilize the energy-yielding products to fix atmospheric nitrogen. This cooperative process was followed over 30 days in sand-based cultures in which the breakdown of 20% of the cellulose and 28 to 30% of the straw resulted in the fixation of 12 to 14.6 mg of N per g of cellulose and 17 to 19 mg of N per g of straw consumed. Cellulomonas species have certain advantages over aerobic cellulose-degrading fungi in being able to degrade cellulose at oxygen concentrations as low as 1% O/sub 2/ (vol/vol) which would allow a close association between cellulose-degrading and microaerobic diazotrophic microorganisms. Cultures inoculated with initially different proportions of A. brasilense and C. gelida all reached a stable ratio of approximately 1 Azospirillum/3 Cellulomonas cells.

  18. Identification of cultural determinants of antibiotic use cited in primary care in Europe: a mixed research synthesis study of integrated design "Culture is all around us".

    Science.gov (United States)

    Touboul-Lundgren, Pia; Jensen, Siri; Drai, Johann; Lindbæk, Morten

    2015-09-17

    Inappropriate antibiotic prescribing, particularly for respiratory tract infections (RTI) in ambulatory care, has become a worldwide public health threat due to resulting antibiotic resistance. In spite of various interventions and campaigns, wide variations in antibiotic use persist between European countries. Cultural determinants are often referred to as a potential cause, but are rarely defined. To our knowledge, so far no systematic literature review has focused on cultural determinants of antibiotic use. The aim of this study was to identify cultural determinants, on a country-specific level in ambulatory care in Europe, and to describe the influence of culture on antibiotic use, using a framework of cultural dimensions. A computer-based systematic literature review was conducted by two research teams, in France and in Norway. Eligible publications included studies exploring antibiotic use in primary care in at least two European countries based on primary study results, featuring a description of cultural determinants, and published between 1997 and 2015. Quality assessment was conducted independently by two researchers, one in each team, using appropriate checklists according to study design. Each included paper was characterized according to method, countries involved, sampling and main results, and cultural determinants mentioned in each selected paper were extracted, described and categorized. Finally, the influence of Hofstede's cultural dimensions associated with antibiotic consumption within a primary care setting was described. Among 24 eligible papers, 11 were rejected according to exclusion criteria. Overall, 13 papers meeting the quality assessment criteria were included, of which 11 used quantitative methods and two qualitative or mixed methods. The study participants were patients (nine studies) and general practitioners (two studies). This literature review identified various cultural determinants either patient-related (illness perception

  19. Genomic Characterization of Dairy Associated Leuconostoc Species and Diversity of Leuconostocs in Undefined Mixed Mesophilic Starter Cultures.

    Science.gov (United States)

    Frantzen, Cyril A; Kot, Witold; Pedersen, Thomas B; Ardö, Ylva M; Broadbent, Jeff R; Neve, Horst; Hansen, Lars H; Dal Bello, Fabio; Østlie, Hilde M; Kleppen, Hans P; Vogensen, Finn K; Holo, Helge

    2017-01-01

    Undefined mesophilic mixed (DL-type) starter cultures are composed of predominantly Lactococcus lactis subspecies and 1-10% Leuconostoc spp. The composition of the Leuconostoc population in the starter culture ultimately affects the characteristics and the quality of the final product. The scientific basis for the taxonomy of dairy relevant leuconostocs can be traced back 50 years, and no documentation on the genomic diversity of leuconostocs in starter cultures exists. We present data on the Leuconostoc population in five DL-type starter cultures commonly used by the dairy industry. The analyses were performed using traditional cultivation methods, and further augmented by next-generation DNA sequencing methods. Bacterial counts for starter cultures cultivated on two different media, MRS and MPCA, revealed large differences in the relative abundance of leuconostocs. Most of the leuconostocs in two of the starter cultures were unable to grow on MRS, emphasizing the limitations of culture-based methods and the importance of careful media selection or use of culture independent methods. Pan-genomic analysis of 59 Leuconostoc genomes enabled differentiation into twelve robust lineages. The genomic analyses show that the dairy-associated leuconostocs are highly adapted to their environment, characterized by the acquisition of genotype traits, such as the ability to metabolize citrate. In particular, Leuconostoc mesenteroides subsp. cremoris display telltale signs of a degenerative evolution, likely resulting from a long period of growth in milk in association with lactococci. Great differences in the metabolic potential between Leuconostoc species and subspecies were revealed. Using targeted amplicon sequencing, the composition of the Leuconostoc population in the five commercial starter cultures was shown to be significantly different. Three of the cultures were dominated by Ln. mesenteroides subspecies cremoris. Leuconostoc pseudomesenteroides dominated in two of the

  20. Human mixed lymphocyte cultures. Evaluation of microculture technique utilizing the multiple automated sample harvester (MASH)

    Science.gov (United States)

    Thurman, G. B.; Strong, D. M.; Ahmed, A.; Green, S. S.; Sell, K. W.; Hartzman, R. J.; Bach, F. H.

    1973-01-01

    Use of lymphocyte cultures for in vitro studies such as pretransplant histocompatibility testing has established the need for standardization of this technique. A microculture technique has been developed that has facilitated the culturing of lymphocytes and increased the quantity of cultures feasible, while lowering the variation between replicate samples. Cultures were prepared for determination of tritiated thymidine incorporation using a Multiple Automated Sample Harvester (MASH). Using this system, the parameters that influence the in vitro responsiveness of human lymphocytes to allogeneic lymphocytes have been investigated. PMID:4271568

  1. Effect of methanogenic substrates on anaerobic oxidation of methane and sulfate reduction by an anaerobic methanotrophic enrichment.

    KAUST Repository

    Meulepas, Roel J W; Jagersma, Christian G; Khadem, Ahmad F; Stams, Alfons J M; Lens, Piet N L

    2010-01-01

    Anaerobic oxidation of methane (AOM) coupled to sulfate reduction (SR) is assumed to be a syntrophic process, in which methanotrophic archaea produce an interspecies electron carrier (IEC), which is subsequently utilized by sulfate-reducing bacteria

  2. Development and testing of the 'Culture of Care Barometer' (CoCB) in healthcare organisations: a mixed methods study.

    Science.gov (United States)

    Rafferty, Anne Marie; Philippou, Julia; Fitzpatrick, Joanne M; Pike, Geoff; Ball, Jane

    2017-08-18

    Concerns about care quality have prompted calls to create workplace cultures conducive to high-quality, safe and compassionate care and to provide a supportive environment in which staff can operate effectively. How healthcare organisations assess their culture of care is an important first step in creating such cultures. This article reports on the development and validation of a tool, the Culture of Care Barometer, designed to assess perceptions of a caring culture among healthcare workers preliminary to culture change. An exploratory mixed methods study designed to develop and test the validity of a tool to measure 'culture of care' through focus groups and questionnaires. Questionnaire development was facilitated through: a literature review, experts generating items of interest and focus group discussions with healthcare staff across specialities, roles and seniority within three types of public healthcare organisations in the UK. The tool was designed to be multiprofessional and pilot tested with a sample of 467 nurses and healthcare support workers in acute care and then validated with a sample of 1698 staff working across acute, mental health and community services in England. Exploratory factor analysis was used to identify dimensions underlying the Barometer. Psychometric testing resulted in the development of a 30-item questionnaire linked to four domains with retained items loading to four factors: organisational values (α=0.93, valid n=1568, M=3.7), team support (α=0.93, valid n=1557, M=3.2), relationships with colleagues (α=0.84, valid n=1617, M=4.0) and job constraints (α=0.70, valid n=1616, M=3.3). The study developed a valid and reliable instrument with which to gauge the different attributes of care culture perceived by healthcare staff with potential for organisational benchmarking. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless

  3. Co-fermentation of cellobiose and xylose by mixed culture of recombinant Saccharomyces cerevisiae and kinetic modeling.

    Science.gov (United States)

    Chen, Yingying; Wu, Ying; Zhu, Baotong; Zhang, Guanyu; Wei, Na

    2018-01-01

    Efficient conversion of cellulosic sugars in cellulosic hydrolysates is important for economically viable production of biofuels from lignocellulosic biomass, but the goal remains a critical challenge. The present study reports a new approach for simultaneous fermentation of cellobiose and xylose by using the co-culture consisting of recombinant Saccharomyces cerevisiae specialist strains. The co-culture system can provide competitive advantage of modularity compared to the single culture system and can be tuned to deal with fluctuations in feedstock composition to achieve robust and cost-effective biofuel production. This study characterized fermentation kinetics of the recombinant cellobiose-consuming S. cerevisiae strain EJ2, xylose-consuming S. cerevisiae strain SR8, and their co-culture. The motivation for kinetic modeling was to provide guidance and prediction of using the co-culture system for simultaneous fermentation of mixed sugars with adjustable biomass of each specialist strain under different substrate concentrations. The kinetic model for the co-culture system was developed based on the pure culture models and incorporated the effects of product inhibition, initial substrate concentration and inoculum size. The model simulations were validated by results from independent fermentation experiments under different substrate conditions, and good agreement was found between model predictions and experimental data from batch fermentation of cellobiose, xylose and their mixtures. Additionally, with the guidance of model prediction, simultaneous co-fermentation of 60 g/L cellobiose and 20 g/L xylose was achieved with the initial cell densities of 0.45 g dry cell weight /L for EJ2 and 0.9 g dry cell weight /L SR8. The results demonstrated that the kinetic modeling could be used to guide the design and optimization of yeast co-culture conditions for achieving simultaneous fermentation of cellobiose and xylose with improved ethanol productivity, which is

  4. Listeria monocytogenes strains show large variations in competitive growth in mixed culture biofilms and suspensions with bacteria from food processing environments.

    Science.gov (United States)

    Heir, Even; Møretrø, Trond; Simensen, Andreas; Langsrud, Solveig

    2018-06-20

    Interactions and competition between resident bacteria in food processing environments could affect their ability to survive, grow and persist in microhabitats and niches in the food industry. In this study, the competitive ability of L. monocytogenes strains grown together in separate culture mixes with other L. monocytogenes (L. mono mix), L. innocua (Listeria mix), Gram-negative bacteria (Gram- mix) and with a multigenera mix (Listeria + Gram- mix) was investigated in biofilms on stainless steel and in suspensions at 12 °C. The mixed cultures included resident bacteria from processing surfaces in meat and salmon industry represented by L. monocytogenes (n = 6), L. innocua (n = 5) and Gram-negative bacteria (n = 6; Acinetobacter sp., Pseudomonas fragi, Pseudomonas fluorescens, Serratia liquefaciens, Stenotrophomonas maltophilia). Despite hampered in growth in mixed cultures, L. monocytogenes established in biofilms with counts at day nine between 7.3 and 9.0 log per coupon with the lowest counts in the Listeria + G- mix that was dominated by Pseudomonas. Specific L. innocua inhibited growth of L. monocytogenes strains differently; inhibition that was further enhanced by the background Gram-negative microbiota. In these multispecies and multibacteria cultures, the growth competitive effects lead to the dominance of a strong competitor L. monocytogenes strain that was only slightly inhibited by L. innocua and showed strong competitive abilities in mixed cultures with resident Gram-negative bacteria. The results indicates complex patterns of bacterial interactions and L. monocytogenes inhibition in the multibacteria cultures that only partially depend on cell contact and likely involve various antagonistic and bacterial tolerance mechanisms. The study indicates large variations among L. monocytogenes in their competitiveness under multibacterial culture conditions that should be considered in further studies towards understanding of L

  5. Salinity Affects the Composition of the Aerobic Methanotroph Community in Alkaline Lake Sediments from the Tibetan Plateau.

    Science.gov (United States)

    Deng, Yongcui; Liu, Yongqin; Dumont, Marc; Conrad, Ralf

    2017-01-01

    Lakes are widely distributed on the Tibetan Plateau, which plays an important role in natural methane emission. Aerobic methanotrophs in lake sediments reduce the amount of methane released into the atmosphere. However, no study to date has analyzed the methanotroph community composition and their driving factors in sediments of these high-altitude lakes (>4000 m). To provide new insights on this aspect, the abundance and composition in the sediments of six high-altitude alkaline lakes (including both freshwater and saline lakes) on the Tibetan Plateau were studied. The quantitative PCR, terminal restriction fragment length polymorphism, and 454-pyrosequencing methods were used to target the pmoA genes. The pmoA gene copies ranged 10 4 -10 6 per gram fresh sediment. Type I methanotrophs predominated in Tibetan lake sediments, with Methylobacter and uncultivated type Ib methanotrophs being dominant in freshwater lakes and Methylomicrobium in saline lakes. Combining the pmoA-pyrosequencing data from Tibetan lakes with other published pmoA-sequencing data from lake sediments of other regions, a significant salinity and alkalinity effect (P = 0.001) was detected, especially salinity, which explained ∼25% of methanotroph community variability. The main effect was Methylomicrobium being dominant (up to 100%) in saline lakes only. In freshwater lakes, however, methanotroph composition was relatively diverse, including Methylobacter, Methylocystis, and uncultured type Ib clusters. This study provides the first methanotroph data for high-altitude lake sediments (>4000 m) and shows that salinity is a driving factor for the community composition of aerobic methanotrophs.

  6. Survival and synergistic growth of mixed cultures of bifidobacteria and lactobacilli combined with prebiotic oligosaccharides in a gastrointestinal tract simulator

    Directory of Open Access Journals (Sweden)

    Signe Adamberg

    2014-07-01

    Full Text Available Background: Probiotics, especially in combination with non-digestible oligosaccharides, may balance the gut microflora while multistrain preparations may express an improved functionality over single strain cultures. In vitro gastrointestinal models enable to test survival and growth dynamics of mixed strain probiotics in a controlled, replicable manner. Methods: The robustness and compatibility of multistrain probiotics composed of bifidobacteria and lactobacilli combined with mixed prebiotics (galacto-, fructo- and xylo-oligosaccharides or galactooligosaccharides and soluble starch were studied using a dynamic gastrointestinal tract simulator (GITS. The exposure to acid and bile of the upper gastrointestinal tract was followed by dilution with a continuous decrease of the dilution rate (de-celerostat to simulate the descending nutrient availability of the large intestine. The bacterial numbers and metabolic products were analyzed and the growth parameters determined. Results: The most acid- and bile-resistant strains were Lactobacillus plantarum F44 and L. paracasei F8. Bifidobacterium breve 46 had the highest specific growth rate and, although sensitive to bile exposure, recovered during the dilution phase in most experiments. B. breve 46, L. plantarum F44, and L. paracasei F8 were selected as the most promising strains for further studies. Conclusions: De-celerostat cultivation can be applied to study the mixed bacterial cultures under defined conditions of decreasing nutrient availability to select a compatible set of strains.

  7. Biohydrogen production from rotten orange with immobilized mixed culture: Effect of immobilization media for various composition of substrates

    Energy Technology Data Exchange (ETDEWEB)

    Damayanti, Astrilia, E-mail: liasholehasd@gmail.com [Department of Chemical Engineering, Faculty of Engineering, Semarang State University, E1 Building, 2nd floor, Kampus Sekaran, Gunungpati, Semarang 50229 (Indonesia); Department of Chemical Engineering, Faculty of Engineering, Gadjah Mada University, Jl. Grafika No. 2, Kampus UGM, Yogyakarta 55281 (Indonesia); Sarto,; Syamsiah, Siti; Sediawan, Wahyudi B. [Department of Chemical Engineering, Faculty of Engineering, Gadjah Mada University, Jl. Grafika No. 2, Kampus UGM, Yogyakarta 55281 (Indonesia)

    2015-12-29

    Enriched–immobilized mixed culture was utilized to produce biohydrogen in mesophilic condition under anaerobic condition using rotten orange as substrate. The process was conducted in batch reactors for 100 hours. Microbial cultures from three different sources were subject to a series of enrichment and immobilized in two different types of media, i.e. calcium alginate (CA, 2%) and mixture of alginate and activated carbon (CAC, 1:1). The performance of immobilized culture in each media was tested for biohydrogen production using four different substrate compositions, namely orange meat (OM), orange meat added with peel (OMP), orange meat added with limonene (OML), and mixture of orange meat and peel added with limonene (OMPL). The results show that, with immobilized culture in CA, the variation of substrate composition gave significant effect on the production of biohydrogen. The highest production of biohydrogen was detected for substrate containing only orange meet, i.e. 2.5%, which was about 3-5 times higher than biohydrogen production from other compositions of substrate. The use of immobilized culture in CAC in general has increased the hydrogen production by 2-7 times depending on the composition of substrate, i.e. 5.4%, 4.8%, 5.1%, and 4.4% for OM, OMP, OML, and OMPL, respectively. The addition of activated carbon has eliminated the effect of inhibitory compounds in the substrate. The major soluble metabolites were acetic acid, propionic acid, and butyric acid.

  8. Biohydrogen production from rotten orange with immobilized mixed culture: Effect of immobilization media for various composition of substrates

    Science.gov (United States)

    Damayanti, Astrilia; Sarto, Syamsiah, Siti; Sediawan, Wahyudi B.

    2015-12-01

    Enriched-immobilized mixed culture was utilized to produce biohydrogen in mesophilic condition under anaerobic condition using rotten orange as substrate. The process was conducted in batch reactors for 100 hours. Microbial cultures from three different sources were subject to a series of enrichment and immobilized in two different types of media, i.e. calcium alginate (CA, 2%) and mixture of alginate and activated carbon (CAC, 1:1). The performance of immobilized culture in each media was tested for biohydrogen production using four different substrate compositions, namely orange meat (OM), orange meat added with peel (OMP), orange meat added with limonene (OML), and mixture of orange meat and peel added with limonene (OMPL). The results show that, with immobilized culture in CA, the variation of substrate composition gave significant effect on the production of biohydrogen. The highest production of biohydrogen was detected for substrate containing only orange meet, i.e. 2.5%, which was about 3-5 times higher than biohydrogen production from other compositions of substrate. The use of immobilized culture in CAC in general has increased the hydrogen production by 2-7 times depending on the composition of substrate, i.e. 5.4%, 4.8%, 5.1%, and 4.4% for OM, OMP, OML, and OMPL, respectively. The addition of activated carbon has eliminated the effect of inhibitory compounds in the substrate. The major soluble metabolites were acetic acid, propionic acid, and butyric acid.

  9. Biohydrogen production from rotten orange with immobilized mixed culture: Effect of immobilization media for various composition of substrates

    International Nuclear Information System (INIS)

    Damayanti, Astrilia; Sarto,; Syamsiah, Siti; Sediawan, Wahyudi B.

    2015-01-01

    Enriched–immobilized mixed culture was utilized to produce biohydrogen in mesophilic condition under anaerobic condition using rotten orange as substrate. The process was conducted in batch reactors for 100 hours. Microbial cultures from three different sources were subject to a series of enrichment and immobilized in two different types of media, i.e. calcium alginate (CA, 2%) and mixture of alginate and activated carbon (CAC, 1:1). The performance of immobilized culture in each media was tested for biohydrogen production using four different substrate compositions, namely orange meat (OM), orange meat added with peel (OMP), orange meat added with limonene (OML), and mixture of orange meat and peel added with limonene (OMPL). The results show that, with immobilized culture in CA, the variation of substrate composition gave significant effect on the production of biohydrogen. The highest production of biohydrogen was detected for substrate containing only orange meet, i.e. 2.5%, which was about 3-5 times higher than biohydrogen production from other compositions of substrate. The use of immobilized culture in CAC in general has increased the hydrogen production by 2-7 times depending on the composition of substrate, i.e. 5.4%, 4.8%, 5.1%, and 4.4% for OM, OMP, OML, and OMPL, respectively. The addition of activated carbon has eliminated the effect of inhibitory compounds in the substrate. The major soluble metabolites were acetic acid, propionic acid, and butyric acid

  10. Incorporating Cultural Perspectives into Diabetes Self-Management Programs for East Asian Immigrants: A Mixed-Study Review.

    Science.gov (United States)

    Park, Chorong; Nam, Soohyun; Whittemore, Robin

    2016-04-01

    It is important to understand East Asian immigrants (EAIs)' unique perspectives in managing diabetes in order to provide culturally-competent care. However, it is not known whether EAIs' perspectives are addressed in diabetes self-management interventions developed for EAIs. Therefore, a mixed-study review was conducted to identify EAIs' perspective from qualitative research (n = 9 studies) and to evaluate the components of EAI diabetes self-management interventions (n = 7). Themes from the qualitative synthesis demonstrated that EAIs have unique cultural values and traditional health beliefs while struggling with multi-contextual barriers due to immigration. The evaluation of EAI diabetes self-management interventions revealed that there was a lack of consensus on cultural strategies for EAIs' across the interventions. Addressing language barriers was the only factor consistently integrated in the cultural components of intervention by employing bilingual interventionists. EAIs' perspectives and experiences need to be incorporated in the future diabetes self-management interventions to better provide culturally-competent care.

  11. Mixed culture models for predicting intestinal microbial interactions between Escherichia coli and Lactobacillus in the presence of probiotic Bacillus subtilis.

    Science.gov (United States)

    Yang, J J; Niu, C C; Guo, X H

    2015-01-01

    Bacillus has been proposed as a probiotic due to its in vivo effectiveness in the gastrointestinal tract through antimicrobial activities. The present study investigates the effects of Lactobacillus alone or in the presence of Bacillus subtilis MA139 on the inhibition of pathogenic Escherichia coli K88. Mixed cultures were used to predict the possible interactions among these bacteria within the intestinal tract of animals. B. subtilis MA139 was first assayed for its inhibition against E. coli K88 both under shaking and static culture conditions. A co-culture assay was employed under static conditions to test the inhibitory effects of Lactobacillus reuteri on E. coli K88, with or without addition of B. subtilis MA139. The results showed that B. subtilis MA139 had marked inhibition against E. coli K88 under shaking conditions and weak inhibition under static conditions. Lactobacillus alone as well as in combination with B. subtilis MA139 spores exerted strong inhibition against E. coli K88 under static conditions. However, the inhibition by Lactobacillus in combination with B. subilis spores was much higher than that by Lactobacillus alone (Psubtilis MA139 significantly decreased the pH and oxidation-reduction potential values of the co-culture broth compared to that of Lactobacillus alone (Psubtilis MA139 because of significantly higher Lactobacillus counts and lower pH values in the broth (PBacillus in the mixed culture models suggests that Bacillus may produce beneficial effects by increasing the viability of lactobacilli and subsequently inhibiting the growth of pathogenic E. coli. Therefore, the combination of Bacillus and Lactobacillus species as a probiotic is recommended.

  12. Aerobic degradation of methyl tert-butyl ether in a closed symbiotic system containing a mixed culture of Chlorella ellipsoidea and Methylibium petroleiphilum PM1.

    Science.gov (United States)

    Zhong, Weihong; Li, Yixiao; Sun, Kedan; Jin, Jing; Li, Xuanzhen; Zhang, Fuming; Chen, Jianmeng

    2011-01-30

    The contamination of groundwater by methyl tert-butyl ether (MTBE) is one of the most serious environmental problems around the world. MTBE degradation in a closed algal-bacterial symbiotic system, containing a mixed culture of Methylibium petroleiphilum PM1 and Chlorella ellipsoidea, was investigated. The algal-bacterial symbiotic system showed increased MTBE degradation. The MTBE-degradation rate in the mixed culture (8.808 ± 0.007 mg l(-1) d(-1)) was higher than that in the pure bacterial culture (5.664 ± 0.017 mg l(-1) d(-1)). The level of dissolved oxygen was also higher in the mixed culture than that in the pure bacterial culture. However, the improved efficiency of MTBE degradation was not in proportional to the biomass of the alga. The optimal ratio of initial cell population of bacteria to algae was 100:1. An immobilized culture of mixed bacteria and algae also showed higher MTBE degradation rate than the immobilized pure bacterial culture. A mixed culture with algae and PM1 immobilized separately in different gel beads showed higher degradation rate (8.496 ± 0.636 mg l(-1) d(-1)) than that obtained with algae and PM1 immobilized in the same gel beads (5.424 ± 0.010 mg l(-1) d(-1)). Copyright © 2010 Elsevier B.V. All rights reserved.

  13. Organisational culture and post-merger integration in an academic health centre: a mixed-methods study.

    Science.gov (United States)

    Ovseiko, Pavel V; Melham, Karen; Fowler, Jan; Buchan, Alastair M

    2015-01-22

    Around the world, the last two decades have been characterised by an increase in the numbers of mergers between healthcare providers, including some of the most prestigious university hospitals and academic health centres. However, many mergers fail to bring the anticipated benefits, and successful post-merger integration in university hospitals and academic health centres is even harder to achieve. An increasing body of literature suggests that organisational culture affects the success of post-merger integration and academic-clinical collaboration. This paper reports findings from a mixed-methods single-site study to examine 1) the perceptions of organisational culture in academic and clinical enterprises at one National Health Service (NHS) trust, and 2) the major cultural issues for its post-merger integration with another NHS trust and strategic partnership with a university. From the entire population of 72 clinician-scientists at one of the legacy NHS trusts, 38 (53%) completed a quantitative Competing Values Framework survey and 24 (33%) also provided qualitative responses. The survey was followed up by semi-structured interviews with six clinician-scientists and a group discussion including five senior managers. The cultures of two legacy NHS trusts differed and were primarily distinct from the culture of the academic enterprise. Major cultural issues were related to the relative size, influence, and history of the legacy NHS trusts, and the implications of these for respective identities, clinical services, and finances. Strategic partnership with a university served as an important ameliorating consideration in reaching trust merger. However, some aspects of university entrepreneurial culture are difficult to reconcile with the NHS service delivery model and may create tension. There are challenges in preserving a more desirable culture at one of the legacy NHS trusts, enhancing cultures in both legacy NHS trusts during their post-merger integration, and

  14. Expanding diversity of potential bacterial partners of the methanotrophic ANME archaea using Magneto-FISH

    Science.gov (United States)

    Trembath-Reichert, E.; Green-Saxena, A.; Steele, J. A.; Orphan, V. J.

    2012-12-01

    Sulfate-coupled anaerobic oxidation of methane (AOM) in marine sediments is the major sink for methane in the oceans. This process is believed to be catalyzed by as yet uncultured syntrophic consortia of ANME archaea (affiliated with the Methanosarcinales) and sulfate-reducing bacteria belonging to the Desulfosarcina/Desulfococcus and Desulfobulbaceae. These syntrophic consortia have been described from methane-rich habitats worldwide and appear to be most concentrated in areas of high methane flux, such as cold seeps along continental margins. The extent of the diversity and ecophysiological potential of these microbial associations is still poorly constrained. In an effort to better characterize the diversity of microorganisms forming associations with different clades of methanotrophic ANME archaea (ANME-1, ANME-2a/b/c, ANME-3) and link these organisms to potentially diagnostic metabolic genes (e.g. mcrA, dsrAB, aprA), we employed a unique culture-independent whole cell capture technique which combines Fluorescence In Situ Hybridization with immuno-magnetic cell capture (Magneto-FISH). We used Magneto-FISH for targeted enrichment of specific ANME groups and their associated bacteria directly from formalin- and ethanol-fixed methane seep sediment. The identity and metabolic gene diversity of captured microorganisms were then assessed by clone library construction and sequencing. Diversity recovered from Magneto-FISH experiments using general and clade-specific ANME targeted probes show both the expected selectivity of the FISH probes (i.e. predominately ANME-2c subclade captured with an ANME-2c probe and multiple ANME groups recovered with the general probe targeting most ANME). Follow up FISH experiments were conducted to confirm physical associations between ANME and unique bacterial members (deltaproteobacteria and other non-sulfate reducing groups) that were common to multiple Magneto-FISH capture experiments. Analyses of metabolic gene diversity for archaeal

  15. A mixed methods study of culturally responsive teaching in science and math classrooms

    Science.gov (United States)

    Holocker, Angela Y.

    Through the dawn of education, student achievement has always been the primary focus of educators. The United States has not changed the structure of their educational institutions since the Industrial Revolution. With the achievement gap between mainstream and non-mainstream students continually growing, it is the responsibility of every educator to contribute to student success. However, teachers cannot be held accountable for teaching what they do not know. This study investigates the correlation between Culturally Responsive Teaching professional development and the effects on minority students. The yearlong professional development models as well as culturally responsive strategies are discussed in great length. The study reflects the attitudes of teachers before and after participation in the culturally responsive professional development. Student growth was tracked over the school year as well as teacher implementation of the culturally responsive strategies. The final teacher survey and overall student growth was analyzed for correlation.

  16. Production of diosgenin from Dioscorea zingiberensis with mixed culture in a new tray bioreactor

    Directory of Open Access Journals (Sweden)

    Yutong Cheng

    2016-01-01

    Full Text Available A new tray bioreactor was developed for the production of diosgenin from Dioscorea zingiberensis with Trichoderma reesei and Aspergillus fumigatus. The influence of initial moisture content, temperature, tray bed depth and mixing times was investigated. The best fermentation condition is initial moisture content of 75%, bioreactor temperature of 35°C, solid bed depth of 1.5 cm and three mixings carrying out on the first, third and fifth day. Under the optimized fermentation conditions, after 144 h incubation, maximum diogenin concentration of 68.2 μmol/g was detected.

  17. Metagenomic identification of active methanogens and methanotrophs in serpentinite springs of the Voltri Massif, Italy

    Directory of Open Access Journals (Sweden)

    William J. Brazelton

    2017-01-01

    Full Text Available The production of hydrogen and methane by geochemical reactions associated with the serpentinization of ultramafic rocks can potentially support subsurface microbial ecosystems independent of the photosynthetic biosphere. Methanogenic and methanotrophic microorganisms are abundant in marine hydrothermal systems heavily influenced by serpentinization, but evidence for methane-cycling archaea and bacteria in continental serpentinite springs has been limited. This report provides metagenomic and experimental evidence for active methanogenesis and methanotrophy by microbial communities in serpentinite springs of the Voltri Massif, Italy. Methanogens belonging to family Methanobacteriaceae and methanotrophic bacteria belonging to family Methylococcaceae were heavily enriched in three ultrabasic springs (pH 12. Metagenomic data also suggest the potential for hydrogen oxidation, hydrogen production, carbon fixation, fermentation, and organic acid metabolism in the ultrabasic springs. The predicted metabolic capabilities are consistent with an active subsurface ecosystem supported by energy and carbon liberated by geochemical reactions within the serpentinite rocks of the Voltri Massif.

  18. The genes and enzymes of sucrose metabolism in moderately thermophilic methanotroph Methylocaldum szegediense O12.

    Science.gov (United States)

    But, Sergey Y; Solntseva, Natalia P; Egorova, Svetlana V; Mustakhimov, Ildar I; Khmelenina, Valentina N; Reshetnikov, Alexander; Trotsenko, Yuri A

    2018-05-01

    Four enzymes involved in sucrose metabolism: sucrose phosphate synthase (Sps), sucrose phosphate phosphatase (Spp), sucrose synthase (Sus) and fructokinase (FruK), were obtained as his-tagged proteins from the moderately thermophilic methanotroph Methylocaldum szegediense O12. Sps, Spp, FruK and Sus demonstrated biochemical properties similar to those of other bacterial counterparts, but the translated amino acid sequences of Sps and Spp displayed high divergence from the respective microbial enzymes. The Sus of M. szegediense O12 catalyzed the reversible reaction of sucrose cleavage in the presence of ADP or UDP and preferred ADP as a substrate, thus implying a connection between sucrose and glycogen metabolism. Sus-like genes were found only in a few methanotrophs, whereas amylosucrase was generally used in sucrose cleavage in this group of bacteria. Like other microbial fructokinases, FruK of M. szegediense O12 showed a high specificity to fructose.

  19. Alcohol production through volatile fatty acids reduction with hydrogen as electron donor by mixed cultures

    NARCIS (Netherlands)

    Steinbusch, K.J.J.; Hamelers, H.V.M.; Buisman, C.J.N.

    2008-01-01

    In this research we demonstrated a new method to produce alcohols. It was experimentally feasible to produce ethanol, propanol and butanol from solely volatile fatty acids (VFAs) with hydrogen as electron donor. In batch tests, VFAs such as acetic, propionic and butyric acids were reduced by mixed

  20. The Politics of Culture: Understanding Local Political Resistance to Detracking in Racially Mixed Schools.

    Science.gov (United States)

    Wells, Amy Stuart; Serna, Irene

    1996-01-01

    A 3-year study of 10 racially mixed schools implementing detracking shows how elite parents undermine the reforms by threatening flight, co-opting those educators who have power and authority, obtaining support of the "not-quite elite," and using bribes. (SK)

  1. Methane and Trichloroethylene Oxidation by an Estuarine Methanotroph, Methylobacter sp. Strain BB5.1

    OpenAIRE

    Smith, Kelly S.; Costello, Andria M.; Lidstrom, Mary E.

    1998-01-01

    An estuarine methanotroph was isolated from sediment enrichments and designated Methylobacter sp. strain BB5.1. In cells grown on medium with added copper, oxidation of methane and trichloroethylene occurred with similar Ks values, but the Vmax for trichloroethylene oxidation was only 0.1% of the methane oxidation Vmax. Cells grown on low-copper medium did not oxidize trichloroethylene and showed a variable rate of methane oxidation.

  2. Effect of Cell-to-matrix Ratio in Polyvinyl Alcohol Immobilized Pure and Mixed Cultures on Atrazine Degradation

    International Nuclear Information System (INIS)

    Siripattanakul, Sumana; Wirojanagud, Wanpen; McEvoy, John; Khan, Eakalak

    2008-01-01

    Atrazine biodegradation by immobilized pure and mixed cultures was examined. A pure atrazine-degrading culture, Agrobacterium radiobacter J14a (J14a), and a mixed culture (MC), isolated from an atrazine-contaminated crop field, were immobilized using phosphorylated-polyvinyl alcohol (PPVA). An existing cell immobilization procedure was modified to enhance PPVA matrix stability. The results showed that the matrices remained mechanically and chemically stable after shaking with glass beads over 15 days under various salt solutions and pH values. The immobilization process had a slight effect on cell viability. With the aid of scanning electron microscopy, a suitable microstructure of PPVA matrices for cell entrapment was observed. There were two porous layers of spherical gel matrices, the outside having an encapsulation property and the inside containing numerous pores for bacteria to occupy. J14a and MC were immobilized at three cell-to-matrix ratios of 3.5, 6.7, and 20 mg dry cells/mL matrix. The atrazine biodegradation tests were conducted in an aerobic batch system, which was inoculated with cells at 2,000 mg/L. The tests were also conducted using free (non-immobilized) J14a and MC for comparative purpose. The cell-to-matrix ratio of 3.5 mg/mL provided the highest atrazine removal efficiency of 40-50% in 120 h for both J14a and MC. The free cell systems, for both cultures, presented much lower atrazine removal efficiencies compared to the immobilized cell systems at the same level of inoculation

  3. Direct Succinic Acid Production from Minimally Pretreated Biomass Using Sequential Solid-State and Slurry Fermentation with Mixed Fungal Cultures

    Directory of Open Access Journals (Sweden)

    Jerico Alcantara

    2017-06-01

    Full Text Available Conventional bio-based succinic acid production involves anaerobic bacterial fermentation of pure sugars. This study explored a new route for directly producing succinic acid from minimally-pretreated lignocellulosic biomass via a consolidated bioprocessing technology employing a mixed lignocellulolytic and acidogenic fungal co-culture. The process involved a solid-state pre-fermentation stage followed by a two-phase slurry fermentation stage. During the solid-state pre-fermentation stage, Aspergillus niger and Trichoderma reesei were co-cultured in a nitrogen-rich substrate (e.g., soybean hull to induce cellulolytic enzyme activity. The ligninolytic fungus Phanerochaete chrysosporium was grown separately on carbon-rich birch wood chips to induce ligninolytic enzymes, rendering the biomass more susceptible to cellulase attack. The solid-state pre-cultures were then combined in a slurry fermentation culture to achieve simultaneous enzymatic cellulolysis and succinic acid production. This approach generated succinic acid at maximum titers of 32.43 g/L after 72 h of batch slurry fermentation (~10 g/L production, and 61.12 g/L after 36 h of addition of fresh birch wood chips at the onset of the slurry fermentation stage (~26 g/L production. Based on this result, this approach is a promising alternative to current bacterial succinic acid production due to its minimal substrate pretreatment requirements, which could reduce production costs.

  4. Proliferation of Peripheral Blood Lymphocytes and Mesenchymal Stromal Cells Derived from Wharton's Jelly in Mixed and Membrane-Separated Cultures.

    Science.gov (United States)

    Poltavtsev, A M; Poltavtseva, R A; Yushina, M N; Pavlovich, S V; Svirshchevskaya, E V

    2017-08-01

    We studied the effect of mesenchymal stromal cells on proliferation of CFSE-stained T cells in mixed and membrane-separated (Transwell) cultures and in 3D culture of mesenchymal stromal cells from Wharton's jelly. The interaction of mesenchymal stromal cells with mitogen-activated peripheral blood lymphocytes from an allogeneic donor was followed by suppression of T-cell proliferation in a wide range of cell proportions. Culturing in the Transwell system showed the absence of suppression assessed by the fraction of proliferating cells and by the cell cycle analysis. In 3D cultures, contact interaction of mesenchymal stromal cells and lymphocytes was demonstrated that led to accumulation of G2/M phase lymphocytes and G0/G1 phase mesenchymal stromal cells. The suppressive effect of mesenchymal stromal cells from Wharton's jelly is mediated by two mechanisms. The effects are realized within 6 days, which suggests that the therapeutic effects of mesenchymal stromal cells persist until their complete elimination from the body.

  5. Inhibitory effect of mycoplasma-released arginase. Activity in mixed-lymphocyte and tumour cell cultures

    DEFF Research Database (Denmark)

    Claesson, M H; Tscherning, T; Nissen, Mogens Holst

    1990-01-01

    inhibition can be reversed by addition of excess arginine to the culture medium. Antisera raised against non-fermenting, but not against fermenting, mycoplasma species block the inhibitory effect of MAE. SDS-PAGE separation of MAE disclosed a broad band at 60 kDa which contained arginase activity when...... assayed in MLC and cell proliferation culture. SDS-PAGE followed by western blotting and reaction with antisera raised against non-fermenting mycoplasma species demonstrated a band at 43 kDa common for these micro-organisms....

  6. Mapping differentiation under mixed culture conditions reveals a tunable continuum of T cell fates.

    Directory of Open Access Journals (Sweden)

    Yaron E Antebi

    2013-07-01

    Full Text Available Cell differentiation is typically directed by external signals that drive opposing regulatory pathways. Studying differentiation under polarizing conditions, with only one input signal provided, is limited in its ability to resolve the logic of interactions between opposing pathways. Dissection of this logic can be facilitated by mapping the system's response to mixtures of input signals, which are expected to occur in vivo, where cells are simultaneously exposed to various signals with potentially opposing effects. Here, we systematically map the response of naïve T cells to mixtures of signals driving differentiation into the Th1 and Th2 lineages. We characterize cell state at the single cell level by measuring levels of the two lineage-specific transcription factors (T-bet and GATA3 and two lineage characteristic cytokines (IFN-γ and IL-4 that are driven by these transcription regulators. We find a continuum of mixed phenotypes in which individual cells co-express the two lineage-specific master regulators at levels that gradually depend on levels of the two input signals. Using mathematical modeling we show that such tunable mixed phenotype arises if autoregulatory positive feedback loops in the gene network regulating this process are gradual and dominant over cross-pathway inhibition. We also find that expression of the lineage-specific cytokines follows two independent stochastic processes that are biased by expression levels of the master regulators. Thus, cytokine expression is highly heterogeneous under mixed conditions, with subpopulations of cells expressing only IFN-γ, only IL-4, both cytokines, or neither. The fraction of cells in each of these subpopulations changes gradually with input conditions, reproducing the continuous internal state at the cell population level. These results suggest a differentiation scheme in which cells reflect uncertainty through a continuously tuneable mixed phenotype combined with a biased

  7. Characterization of culturable yeast species associating with whole crop corn and total mixed ration silage

    OpenAIRE

    Wang, Huili; Hao, Wei; Ning, Tingting; Zheng, Mingli; Xu, Chuncheng

    2017-01-01

    Objective This study investigated the association of yeast species with improved aerobic stability of total mixed ration (TMR) silages with prolonged ensiling, and clarified the characteristics of yeast species and their role during aerobic deterioration. Methods Whole crop corn (WCC) silages and TMR silages formulated with WCC were ensiled for 7, 14, 28, and 56 d and used for an aerobic stability test. Predominant yeast species were isolated from different periods and identified by sequencin...

  8. Ammonium carboxylate production from sugarcane trash using long-term air-lime pretreatment followed by mixed-culture fermentation.

    Science.gov (United States)

    Nachiappan, Balasubramaniyan; Fu, Zhihong; Holtzapple, Mark T

    2011-03-01

    Sugarcane trash (ST) was converted to ammonium carboxylates using a novel bioprocessing strategy known as long-term air-lime pretreatment/mixed-culture fermentation. At mild conditions (50°C, 5 weeks, 1-atm air, and excess lime loading of 0.4 g Ca(OH)(2)/(g dry biomass)), air-lime pretreatment of ST had moderate delignification (64.4%) with little loss in polysaccharides. Without employing detoxification, sterility, expensive nutrients, or costly enzymes, the feedstock (80% treated ST/20% chicken manure) was fermented to primarily ammonium acetate (>75%) and butyrate by a mixed culture of marine microorganisms at 55°C. In the best four-stage countercurrent fermentation, the product yield was 0.36 g total acids/(g VS fed) and the substrate conversion was 64%. Model predictions indicate both high acid concentrations (>47.5 g/L) and high substrate conversions (>70%) are possible at industrial scale. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Detoxification Treatments of Free Gossypol in Cottonseed Meal by Microbial Treatment of Mixed Cultures and Biochemical Evaluation on Rabbits

    International Nuclear Information System (INIS)

    Atia, A.I.; Abdel- Rahim, G.A.

    2009-01-01

    Detoxification of ti-ee gossypol (FG) in cottonseed meal (CSM) by Saccharomyces cerevisiae and Aspergillus niger, as a mixed culture, was carried out in solid state fermentation (SSF). Experiments were adopted to optimize the fermentation conditions. Maximum detoxification efficiency (90.2%) occurred after 48 h of incubation at 30 degree C in a 250 ml conical flask containing 15 g of CSM supplemented with 1 % (w/w) (NH 4 ) 2 SO 4 at the optimal conditions including the initial moisture content 55% (w/w) and inoculum level at 5% (v/w). The detoxification of FG was a growth-associated process, which was highly correlated with the dry matter weight loss. Moreover, high activities of hydrolytic enzymes were also produced in solid state fermentation, which enhanced the nutritive value of the detoxified cottonseed powder. A total number of 48 white New Zealand male rabbits were used to biologically examine the feeding of treated (detoxified) CSM without any adverse effects. Hematological and biochemical relevant parameters of white New Zealand male rabbits as affected by feeding treated meal were in the normal physiological range without no obvious change. No significant changes in liver and kidney functions of the rabbits weight gain, feed conversion and efficiency did not significantly change among experimental groups. The study showed that the feeding of the detoxified CSM by S. cerevisiae and A. niger as a mixed culture in this research without any adverse effects on rabbits

  10. Investigation of Acidithiobacillus ferrooxidans in pure and mixed-species culture for bioleaching of Theisen sludge from former copper smelting.

    Science.gov (United States)

    Klink, C; Eisen, S; Daus, B; Heim, J; Schlömann, M; Schopf, S

    2016-06-01

    The aim of this study was to investigate the potential of bioleaching for the treatment of an environmentally hazardous waste, a blast-furnace flue dust designated Theisen sludge. Bioleaching of Theisen sludge was investigated at acidic conditions with Acidithiobacillus ferrooxidans in pure and mixed-species culture with Acidiphilium. In shaking-flask experiments, bioleaching parameters (pH, redox potential, zinc extraction from ZnS, ferrous- and ferric-iron concentration) were controlled regularly. The analysis of the dissolved metals showed that 70% zinc and 45% copper were extracted. Investigations regarding the arsenic and antimony species were performed. When iron ions were lacking, animonate (Sb(V)) and total arsenic concentration were highest in solution. The bioleaching approach was scaled up in stirred-tank bioreactors resulting in higher leaching efficiency of valuable trace elements. Concentrations of dissolved antimony were approx. 23 times, and of cobalt, germanium, and rhenium three times higher in comparison to shaking-flask experiments, when considering the difference in solid load of Theisen sludge. The extraction of base and trace metals from Theisen sludge, despite of its high content of heavy metals and organic compounds, was feasible with iron-oxidizing acidophilic bacteria. In stirred-tank bioreactors, the mixed-species culture performed better. To the best of our knowledge, this study is the first providing an appropriate biological technology for the treatment of Theisen sludge to win valuable elements. © 2016 The Society for Applied Microbiology.

  11. Simultaneous Saccharification and Fermentation of Sugar Beet Pulp with Mixed Bacterial Cultures for Lactic Acid and Propylene Glycol Production

    Directory of Open Access Journals (Sweden)

    Joanna Berlowska

    2016-10-01

    Full Text Available Research into fermentative production of lactic acid from agricultural by-products has recently concentrated on the direct conversion of biomass, whereby pure sugars are replaced with inexpensive feedstock in the process of lactic acid production. In our studies, for the first time, the source of carbon used is sugar beet pulp, generated as a by-product of industrial sugar production. In this paper, we focus on the simultaneous saccharification of lignocellulosic biomass and fermentation of lactic acid, using mixed cultures with complementary assimilation profiles. Lactic acid is one of the primary platform chemicals, and can be used to synthesize a wide variety of useful products, including green propylene glycol. A series of controlled batch fermentations was conducted under various conditions, including pretreatment with enzymatic hydrolysis. Inoculation was performed in two sequential stages, to avoid carbon catabolite repression. Biologically-synthesized lactic acid was catalytically reduced to propylene glycol over 5% Ru/C. The highest lactic acid yield was obtained with mixed cultures. The yield of propylene glycol from the biological lactic acid was similar to that obtained with a water solution of pure lactic acid. Our results show that simultaneous saccharification and fermentation enables generation of lactic acid, suitable for further chemical transformations, from agricultural residues.

  12. Targeted Query Expansions as a Method for Searching Mixed Quality Digitized Cultural Heritage Documents

    NARCIS (Netherlands)

    Keskustalo, H.; Kettunen, K.; Kumpulainen, S.; Ferro, N.; Silvello, G.; Järvelin, A.; Kekäläinen, J.; Arvola, P.; Saastamoinen, M.; Sormunen, E.; Järvelin, K.

    2015-01-01

    Digitization of cultural heritage is a huge ongoing effort in many countries. In digitized historical documents, words may occur in different surface forms due to three types of variation - morphological variation, historical variation, and errors in optical character recognition (OCR). Because

  13. Mixed reality, ubiquitous computing and augmented places as format for communicating culture

    DEFF Research Database (Denmark)

    Sandvik, Kjetil

    2012-01-01

    and co-creation. Digital augmentation of physical places makes us see things in new ways. Buildings are not just buildings, streets are not just streets – they carry stories, they carry cultural meaning which audiences through the interplay between physical locations and the mobile media may acquire...

  14. Overcoming Cross-Cultural Group Work Tensions: Mixed Student Perspectives on the Role of Social Relationships

    Science.gov (United States)

    Mittelmeier, Jenna; Rienties, Bart; Tempelaar, Dirk; Whitelock, Denise

    2018-01-01

    As universities worldwide rapidly internationalise, higher education classrooms have become unique spaces for collaboration between students from different countries. One common way to encourage collaboration between diverse peers is through group work. However, previous research has highlighted that cross-cultural group work can be challenging…

  15. Mixed culture of tilapia (Oreochromis niloticus) and freshwater prawn (Macrobrachium rosenbergii) in periphyton-based ponds

    NARCIS (Netherlands)

    Uddin, S.

    2007-01-01

    In recent years, the concept of periphyton-based aquaculture has been tested and applied in aquaculture. Positive effects of substrate addition for periphyton development included increasing the food supply and providing shelter for culture animals. The aim of this project was to develop a low-cost

  16. Food safety culture assessment using a comprehensive mixed-methods approach

    NARCIS (Netherlands)

    Nyarugwe, Shingai P.; Linnemann, Anita; Nyanga, Loveness K.; Fogliano, Vincenzo; Luning, Pieternel A.

    2018-01-01

    Food safety challenges are a global concern especially in emerging economies, which are in the midst of developmental changes. The challenges are directly or indirectly related to the behaviour and decision-making of personnel, and to an organisation's food safety culture. This study evaluated the

  17. Diversity of the active methanotrophic community in acidic peatlands as assessed by mRNA and SIP-PLFA analyses.

    Science.gov (United States)

    Chen, Yin; Dumont, Marc G; McNamara, Niall P; Chamberlain, Paul M; Bodrossy, Levente; Stralis-Pavese, Nancy; Murrell, J Colin

    2008-02-01

    The active methanotroph community was investigated for the first time in heather (Calluna)-covered moorlands and Sphagnum/Eriophorum-covered UK peatlands. Direct extraction of mRNA from these soils facilitated detection of expression of methane monooxygenase genes, which revealed that particulate methane monooxygenase and not soluble methane monooxygenase was probably responsible for CH(4) oxidation in situ, because only pmoA transcripts (encoding a subunit of particulate methane monooxygenase) were readily detectable. Differences in methanotroph community structures were observed between the Calluna-covered moorland and Sphagnum/Eriophorum-covered gully habitats. As with many other Sphagnum-covered peatlands, the Sphagnum/Eriophorum-covered gullies were dominated by Methylocystis. Methylocella and Methylocapsa-related species were also present. Methylobacter-related species were found as demonstrated by the use of a pmoA-based diagnostic microarray. In Calluna-covered moorlands, in addition to Methylocella and Methylocystis, a unique group of peat-associated type I methanotrophs (Gammaproteobacteria) and a group of uncultivated type II methanotrophs (Alphaproteobacteria) were also found. The pmoA sequences of the latter were only distantly related to Methylocapsa and also to the RA-14 group of methanotrophs, which are believed to be involved in oxidation of atmospheric concentrations of CH(4). Soil samples were also labelled with (13)CH(4), and subsequent analysis of the (13)C-labelled phospholipid fatty acids (PLFAs) showed that 16:1 omega 7, 18:1 omega 7 and 18:1 omega 9 were the major labelled PLFAs. The presence of (13)C-labelled 18:1 omega 9, which was not a major PLFA of any extant methanotrophs, indicated the presence of novel methanotrophs in this peatland.

  18. Enhanced extraction of heavy metals in the two-step process with the mixed culture of Lactobacillus bulgaricus and Streptococcus thermophilus.

    Science.gov (United States)

    Chang, Young-Cheol; Choi, DuBok; Kikuchi, Shintaro

    2012-01-01

    For biological extraction of heavy metals from chromated copper arsenate (CCA) treated wood, different bacteria were investigated. The extraction rates of heavy metals using Lactobacillusbulgaricus and Streptococcusthermophilus were highest. The chemical extraction rates were depended on the amounts of pyruvic acid and lactic acid. Especially, the extraction rates using mixed pyruvic acid and lactic acid were increased compared to those of sole one. They were also enhanced in the mixed culture of L. bulgaricus and S. thermophilus. To improve the extraction of CCA, a two-step processing procedure with the mixed culture of L. bulgaricus and S. thermophilus was conducted. A maximum of 93% of copper, 86.5% of chromium, and 97.8% of arsenic were extracted after 4 days. These results suggest that a two-step process with the mixed culture of L. bulgaricus and S. thermophilus is most effective to extract heavy metals from CCA treated wood. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. A Highly Efficient Mixed-culture Biofilm as Anodic Catalyst and Insights into Its Enhancement through Electrochemistry by Comparison with G. sulfurreducens

    International Nuclear Information System (INIS)

    Liu, Ying; Deng, Dandan; Lan, Xiaoji

    2015-01-01

    Highlights: • A mixed-culture biofilm with 68.6% higher current than Geobacter sulfurreducens was firstly reported, while G. sulfurreducens biofilm showed five-time higher apparent affinity than the mixed-culture. • The mixed-culture biofilm showed surface-controlled process, while diffusion-controlled process was obtained for G. sulfurreducens as at certain accelerating scan rates. • When the used medium was replaced with the fresh, decrease percentage of currents for both kinds of biofilms is similar (50%). • A suitable community will be an alternative for improving MFC performance. - Abstract: In this paper an efficient mixed-culture microbial biofilm with increased current density by 68.6% (1020.9 ± 47 μA cm −2 ) than that on typical culture of Geobacter sulfurreducens biofilm was firstly reported. The insights into the enhanced electricity-producing ability was investigated through evaluating the dependence of limiting current density on electroactive biomass coverage, replacing used growth medium, applying stirring and electron transfer kinetics. It was shown that the enhanced electricity generation ability of the mixed-culture biofilm is from population superiority of active molecules or electron shuttles from the biofilm. This work suggested that the optimized synergistic effect between interspecies in community could significantly improve electricity-producing performance than single strain. This study highlighted the potential synergistic role in special community on electricity generation capability

  20. Microbial conversion of sulfur dioxide in flue gas to sulfide using bulk drug industry wastewater as an organic source by mixed cultures of sulfate reducing bacteria

    International Nuclear Information System (INIS)

    Rao, A. Gangagni; Ravichandra, P.; Joseph, Johny; Jetty, Annapurna; Sarma, P.N.

    2007-01-01

    Mixed cultures of sulfate reducing bacteria (SRB) were isolated from anaerobic cultures and enriched with SRB media. Studies on batch and continuous reactors for the removal of SO 2 with bulk drug industry wastewater as an organic source using isolated mixed cultures of SRB revealed that isolation and enrichment methodology adopted in the present study were apt to suppress the undesirable growth of anaerobic bacteria other than SRB. Studies on anaerobic reactors showed that process was sustainable at COD/S ratio of 2.2 and above with optimum sulfur loading rate (SLR) of 5.46 kg S/(m 3 day), organic loading rate (OLR) of 12.63 kg COD/(m 3 day) and at hydraulic residence time (HRT) of 8 h. Free sulfide (FS) concentration in the range of 300-390 mg FS/l was found to be inhibitory to mixed cultures of SRB used in the present studies

  1. Sedimentation of mixed cultures using natural coagulants for the treatment of effluents generated in terrestrial fuel distribution terminals

    International Nuclear Information System (INIS)

    Vieira, R.B.; Vieira, P.A.; Cardoso, S.L.; Ribeiro, E.J.; Cardoso, V.L.

    2012-01-01

    Highlights: ► Moringa oleifera and chitosan as natural coagulant. ► Chitosan is a superior coagulant compared with Moringa oleifera for the sedimentation. ► Chitosan reduced the process cost without compromising the process performance. - Abstract: This study evaluated the use of natural coagulants (Moringa oleifera and chitosan) under different conditions with a mixed culture (C1 mixed culture). This culture was used for the biodegradation of hydrocarbons present in the effluent from fuel distribution terminals contaminated with diesel oil and gasoline. The biodegradation was evaluated by two central composite design (CCD) experiments: the first with varying concentrations of Moringa oleifera (MO), drying temperatures (TE) and seed drying times (TI); the second with varying concentrations of chitosan and the hydrochloric acid in which chitosan had been solubilized. The responses monitored in the CCD experiments included the sludge volume index (SVI), the turbidity removal (TR) and the specific rate of oxygen uptake (SOUR). Subsequently, the biodegradation was monitored in a sequencing batch reactor (SBR) under the optimal conditions obtained for each CCD experiment. The results indicated that the best coagulant was chitosan solubilized in 0.25 N HCl at a concentration of 50 mg/L. Within five cycles with chitosan as a coagulant, the total organic carbon (TOC) removal increased from 77 ± 1.0% to 82 ± 0.5%, the volatile suspended solids (VSS) increased from 1.4 ± 0.3 to 2.25 ± 0.3 g/L and the total petroleum hydrocarbon (TPH) removal increased from 75 ± 1.0% to 81 ± 0.5%.

  2. Sedimentation of mixed cultures using natural coagulants for the treatment of effluents generated in terrestrial fuel distribution terminals

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, R.B., E-mail: rafaelbrunovieira@yahoo.com.br [Faculdade de Engenharia Quimica - Universidade Federal de Uberlandia, Campus Santa Monica, 2121 - CEP: 38400-902, Uberlandia, MG (Brazil); Vieira, P.A., E-mail: patriciavieira@feq.ufu.br [Faculdade de Engenharia Quimica - Universidade Federal de Uberlandia, Campus Santa Monica, 2121 - CEP: 38400-902, Uberlandia, MG (Brazil); Cardoso, S.L., E-mail: saulo_shaulin_@hotmail.com [Faculdade de Engenharia Quimica - Universidade Federal de Uberlandia, Campus Santa Monica, 2121 - CEP: 38400-902, Uberlandia, MG (Brazil); Ribeiro, E.J., E-mail: ejribeiro@ufu.br [Faculdade de Engenharia Quimica - Universidade Federal de Uberlandia, Campus Santa Monica, 2121 - CEP: 38400-902, Uberlandia, MG (Brazil); Cardoso, V.L., E-mail: vicelma@ufu.br [Faculdade de Engenharia Quimica - Universidade Federal de Uberlandia, Campus Santa Monica, 2121 - CEP: 38400-902, Uberlandia, MG (Brazil)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Moringa oleifera and chitosan as natural coagulant. Black-Right-Pointing-Pointer Chitosan is a superior coagulant compared with Moringa oleifera for the sedimentation. Black-Right-Pointing-Pointer Chitosan reduced the process cost without compromising the process performance. - Abstract: This study evaluated the use of natural coagulants (Moringa oleifera and chitosan) under different conditions with a mixed culture (C1 mixed culture). This culture was used for the biodegradation of hydrocarbons present in the effluent from fuel distribution terminals contaminated with diesel oil and gasoline. The biodegradation was evaluated by two central composite design (CCD) experiments: the first with varying concentrations of Moringa oleifera (MO), drying temperatures (TE) and seed drying times (TI); the second with varying concentrations of chitosan and the hydrochloric acid in which chitosan had been solubilized. The responses monitored in the CCD experiments included the sludge volume index (SVI), the turbidity removal (TR) and the specific rate of oxygen uptake (SOUR). Subsequently, the biodegradation was monitored in a sequencing batch reactor (SBR) under the optimal conditions obtained for each CCD experiment. The results indicated that the best coagulant was chitosan solubilized in 0.25 N HCl at a concentration of 50 mg/L. Within five cycles with chitosan as a coagulant, the total organic carbon (TOC) removal increased from 77 {+-} 1.0% to 82 {+-} 0.5%, the volatile suspended solids (VSS) increased from 1.4 {+-} 0.3 to 2.25 {+-} 0.3 g/L and the total petroleum hydrocarbon (TPH) removal increased from 75 {+-} 1.0% to 81 {+-} 0.5%.

  3. Dangerous to mix: culture and politics in a traditional circumcision in South Africa.

    Science.gov (United States)

    Banwari, Meel

    2015-03-01

    Traditional circumcision (initiation) is an integral part of the Xhosa speaking communities. Circumcision is the first step towards manhood. It involves a number of cultural, religious, legal and ethical issues, which in terms of the constitution of the Republic of South Africa, are rights that must be protected. To highlight the problem of circumcision related death in South Africa. This case report examines a 16- year boy who had died as result of botched circumcision by an unqualified traditional surgeon. He kept the boy in his custody despite his serious illness. He applied a tight bandage to control the bleeding, resulting in gangrene of the penis followed by septicemia. The histories, postmortem findings, cause of death and medico- legal and social aspects have been discussed in this manuscript. There are unacceptable deaths related with circumcision in South Africa. The right to life cannot be sacrificed at the altar of culture and politics.

  4. Cultural border crossing in three urban classrooms: A mixed methods study

    Science.gov (United States)

    Roopnarine, Rupnarain

    This study examined the effects of the instruction of four youth cultural border crossing behaviors: flexibility, being at ease, playfulness, and citizenship as an intervention aimed at helping students to transition across three borders, student to student, student to science, and student to teacher. The research involved 12 ninth- and 10th-grade students in a large urban school district in three diverse classrooms, A, B, and C. Four students in each classroom volunteered for the study. The students in Groups A and B were in 9th grade Living Environment and students in Group B were in 10th grade chemistry. These students participated in this instructional intervention for three months. The study was conducted using both quantitative and qualitative methods based on participant observations, interviews, and questionnaire. The result indicated that there was no significant effect of the cultural border crossing instructions on the students' interactions across the three borders examined. However, the instructions helped Group A and Group B to be more flexible but not group C. Also, the instructions helped Group A to be more playful and at ease but not Group B and C. The instructions also helped Group A to show more citizenship but not Group B and C. In addition, there was no difference between the pretest and posttest cultural bother crossing behavior. Moreover, qualitative data analysis showed that the participants were more flexible, at ease, and playful among peers than across student to teacher and student to science borders. Also, the use of citizenship in the three groups showed no effect on the participants' interaction with peers. Although, the findings showed no effect of cultural border crossing instructions on students' interactions, it is suggested that we continue to find ways to help students feel more comfortable in science.

  5. Effects of granular activated carbon on methane removal performance and methanotrophic community of a lab-scale bioreactor.

    Science.gov (United States)

    Lee, Eun-Hee; Choi, Sun-Ah; Yi, Taewoo; Kim, Tae Gwan; Lee, Sang-Don; Cho, Kyung-Suk

    2015-01-01

    Two identical lab-scale bioreactor systems were operated to examine the effects of granular activated carbon (GAC) on methane removal performance and methanotrophic community. Both bioreactor systems removed methane completely at a CH4 loading rate of 71.2 g-CH4·d(-1) for 17 days. However, the methane removal efficiency declined to 88% in the bioreactor without GAC, while the bioreactor amended with GAC showed greater methane removal efficiency of 97% at a CH4 loading rate of 107.5 g-CH4·d(-1). Although quantitative real-time PCR showed that methanotrophic populations were similar levels of 5-10 × 10(8) pmoA gene copy number·VSS(-1) in both systems, GAC addition changed the methanotrophic community composition of the bioreactor systems. Microarray assay revealed that GAC enhanced the type I methanotrophic genera including Methylobacter, Methylomicrobium, and Methylomonas of the system, which suggests that GAC probably provided a favorable environment for type I methanotrophs. These results indicated that GAC is a promising support material in bioreactor systems for CH4 mitigation.

  6. The relative contribution of methanotrophs to microbial communities and carbon cycling in soil overlying a coal-bed methane seep

    Science.gov (United States)

    Mills, Christopher T.; Slater, Gregory F.; Dias, Robert F.; Carr, Stephanie A.; Reddy, Christopher M.; Schmidt, Raleigh; Mandernack, Kevin W.

    2013-01-01

    Seepage of coal-bed methane (CBM) through soils is a potential source of atmospheric CH4 and also a likely source of ancient (i.e. 14C-dead) carbon to soil microbial communities. Natural abundance 13C and 14C compositions of bacterial membrane phospholipid fatty acids (PLFAs) and soil gas CO2 and CH4 were used to assess the incorporation of CBM-derived carbon into methanotrophs and other members of the soil microbial community. Concentrations of type I and type II methanotroph PLFA biomarkers (16:1ω8c and 18:1ω8c, respectively) were elevated in CBM-impacted soils compared with a control site. Comparison of PLFA and 16s rDNA data suggested type I and II methanotroph populations were well estimated and overestimated by their PLFA biomarkers, respectively. The δ13C values of PLFAs common in type I and II methanotrophs were as negative as −67‰ and consistent with the assimilation of CBM. PLFAs more indicative of nonmethanotrophic bacteria had δ13C values that were intermediate indicating assimilation of both plant- and CBM-derived carbon. Δ14C values of select PLFAs (−351 to −936‰) indicated similar patterns of CBM assimilation by methanotrophs and nonmethanotrophs and were used to estimate that 35–91% of carbon assimilated by nonmethanotrophs was derived from CBM depending on time of sampling and soil depth.

  7. Biodegradation of Maya crude oil fractions by bacterial strains and a defined mixed culture isolated from Cyperus laxus rhizosphere soil in a contaminated site

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Ramirez, I. J.; Gutierrez-Rojas, M.; Favela-Torres, E. [Autonomous Metropolitan University (UAM)- Iztapalapa, Dept. of Biotechnology, Federal District (Mexico); Ramirez-Sada, H. [Autonomous Metropolitan University (UAM)-Xochimilco, Dept. of Biological Systems, Federal District (Mexico)

    2003-12-01

    Biodegradation of aliphatic, aromatic, and polar constituents of Maya crude oil by a set of isolated bacterial strains and a defined mixed culture made up with all isolated strains, was evaluated. The bacterial strains were obtained from the rhizosphere of Cyperus laxus, a native plant on a highly hydrocarbon-polluted site. Oxygen uptake rate was used to determine the culture transfer timing during the enrichment culture. Results showed that five of the isolated strains were able to degrade 50 per cent of the aliphatic fractions of Maya crude oil. With the defined mixed culture the level of biodegradation was 47 per cent for aliphatics and 6 per cent of the aromatic-polar mixture. When grown in the presence of total hydrocarbons, the defined mixed culture was able to degrade 40 per cent of the aliphatic fraction and 26 per cent of the aromatic fraction. By combining enrichment cultures with oxygen uptake rate to determine the culture transfer timing during the enrichment cultures allowed the isolation of bacterial strains that are able to degrade specific hydrocarbon fractions at high consumption rates. 28 refs., 4 tabs., 1 fig.

  8. A safety culture assessment by mixed methods at a public maternity and infant hospital in China

    OpenAIRE

    Listyowardojo, Tita Alissa; Yan, Xiaoling; Leyshon, Stephen; Ray-Sannerud, Bobbie; Yu, Xin Yan; Zheng, Kai; Duan, Tao

    2017-01-01

    Tita Alissa Listyowardojo,1 Xiaoling Yan,2,3 Stephen Leyshon,1 Bobbie Ray-Sannerud,1 Xin Yan Yu,4 Kai Zheng,4 Tao Duan2,3 1Life Sciences Program, Group Technology and Research, DNV GL, Hovik, Norway; 2Quality and Safety Department, Shanghai First Maternity and Infant Hospital, 3Tongji University School of Medicine, Shanghai, 4Healthcare Department, Business Assurance, DNV GL, Beijing, China Objective: To assess safety culture at a public maternity hospital in Shanghai, China, using a sequenti...

  9. Influencing factors analysis of anammox bacteria cultured by mixing denitrifying-anammox

    OpenAIRE

    Sihui WANG; Yuanyuan SONG; Yunman LIU; Yankai GUO; Jing LIAN; Jianbo GUO

    2017-01-01

    In order to get the optimal growth conditions of anammox bacteria, the mature-cultured anammox granule sludge is used to investigate the influencing factors. The effects of temperature, pH value, COD and influent substrate (NO-2-N and NH+4-N) on anammox bacteria activity are investigated. The results demonstrate that the optimal temperature is 40 ℃ and the optimal pH value is between 7.0~8.0 for anammox bacteria. The anammox bacteria activity is not inhibited severely when COD concentration i...

  10. Women's status and experiences of mistreatment during childbirth in Uttar Pradesh: a mixed methods study using cultural health capital theory.

    Science.gov (United States)

    Sudhinaraset, May; Treleaven, Emily; Melo, Jason; Singh, Kanksha; Diamond-Smith, Nadia

    2016-10-28

    Mistreatment of women in healthcare settings during childbirth has been gaining attention globally. Mistreatment during childbirth directly and indirectly affects health outcomes, patient satisfaction, and the likelihood of delivering in a facility currently or in the future. It is important that we study patients' reports of mistreatment and abuse to develop a deeper understanding of how it is perpetrated, its consequences, and to identify potential points of intervention. Patients' perception of the quality of care is dependent, not only on the content of care, but importantly, on women's expectations of care. This study uses rich, mixed-methods data to explore women's characteristics and experiences of mistreatment during childbirth among slum-resident women in Uttar Pradesh, India. To understand the ways in which women's social and cultural factors influence their expectations of care and consequently their perceptions of respectful care, we adopt a Cultural Health Capital (CHC) framework. The quantitative sample includes 392 women, and the qualitative sample includes 26 women. Quantitative results suggest high levels of mistreatment (over 57 % of women reported any form of mistreatment). Qualitative findings suggest that lack of cultural health capital disadvantages patients in their patient-provider relationships, and that women use resources to improve care they receive. Participants articulated how providers set expectations and norms regarding behaviors in facilities; patients with lower social standing may not always understand standard practices and are likely to suffer poor health outcomes as a result. Of importance, however, patients also blame themselves for their own lack of knowledge. Lack of cultural health capital disadvantages women during delivery care in India. Providers set expectations and norms around behaviors during delivery, while women are often misinformed and may have low expectations of care.

  11. Scholars versus Practitioners?: Anchor Proof Testing and the Birth of a Mixed Culture in Eighteenth-Century France.

    Science.gov (United States)

    Orain, Arnaud; Laubé, Sylvain

    In line with studies that question the conventional dichotomies between "head" and "hand," this article analyzes the emergence of a mixed naval culture, between science and technology, during the French Enlightenment. The case at issue is that of the circuitous development of an anchor proof testing protocol, an important method in the competition for maritime supremacy used at least until the first third of the nineteenth century. The story begins in the dockyard of Brest with a humble boatswain, and continues with the dissemination of his experiments thanks to prominent figures of the Naval Academy of Brest and of the Royal Academy of Sciences of Paris. The article suggests that if the findings of the latter were rather inconclusive, nevertheless, over time, a collaboration between practitioners and scientists did eventually generate a regular protocol for testing anchors.

  12. Harnessing a methane-fueled, sediment-free mixed microbial community for utilization of distributed sources of natural gas.

    Science.gov (United States)

    Marlow, Jeffrey J; Kumar, Amit; Enalls, Brandon C; Reynard, Linda M; Tuross, Noreen; Stephanopoulos, Gregory; Girguis, Peter

    2018-06-01

    Harnessing the metabolic potential of uncultured microbial communities is a compelling opportunity for the biotechnology industry, an approach that would vastly expand the portfolio of usable feedstocks. Methane is particularly promising because it is abundant and energy-rich, yet the most efficient methane-activating metabolic pathways involve mixed communities of anaerobic methanotrophic archaea and sulfate reducing bacteria. These communities oxidize methane at high catabolic efficiency and produce chemically reduced by-products at a comparable rate and in near-stoichiometric proportion to methane consumption. These reduced compounds can be used for feedstock and downstream chemical production, and at the production rates observed in situ they are an appealing, cost-effective prospect. Notably, the microbial constituents responsible for this bioconversion are most prominent in select deep-sea sediments, and while they can be kept active at surface pressures, they have not yet been cultured in the lab. In an industrial capacity, deep-sea sediments could be periodically recovered and replenished, but the associated technical challenges and substantial costs make this an untenable approach for full-scale operations. In this study, we present a novel method for incorporating methanotrophic communities into bioindustrial processes through abstraction onto low mass, easily transportable carbon cloth artificial substrates. Using Gulf of Mexico methane seep sediment as inoculum, optimal physicochemical parameters were established for methane-oxidizing, sulfide-generating mesocosm incubations. Metabolic activity required >∼40% seawater salinity, peaking at 100% salinity and 35 °C. Microbial communities were successfully transferred to a carbon cloth substrate, and rates of methane-dependent sulfide production increased more than threefold per unit volume. Phylogenetic analyses indicated that carbon cloth-based communities were substantially streamlined and were

  13. The effect of heat pretreatment temperature on fermentative hydrogen production using mixed cultures

    Energy Technology Data Exchange (ETDEWEB)

    Baghchehsaraee, Bita; Nakhla, George; Karamanev, Dimitre; Margaritis, Argyrios [Department of Chemical and Biochemical Engineering, The University of Western Ontario, London, Ontario N6A 5B9 (Canada); Reid, Gregor [Department of Microbiology and Immunology, The University of Western Ontario, London, Ontario (Canada); Canadian Research and Development Center for Probiotics, Lawson Health Research Institute, 268 Grosvenor Street, London, Ontario N6A 4V2 (Canada)

    2008-08-15

    The effect of heat treatment at different temperatures on two types of inocula, activated sludge and anaerobically digested sludge, was investigated in batch cultures. Heat treatments were conducted at 65, 80 and 95 C for 30 min. The untreated inocula produced less amount of hydrogen than the pretreated inocula, with lactic acid as the main metabolite. The maximum yields of 2.3 and 1.6 mol H{sub 2}/mol glucose were achieved for the 65 C pretreated anaerobically digested and activated sludges, respectively. Approximately a 15% decrease in yield was observed with increasing pretreatment temperature from 65 to 95 C concomitant with an increase in butyrate/acetate ratio from 1.5 to 2.4 for anaerobically digested sludge. The increase of pretreatment temperature of activated sludge to 95 C suppressed the hydrogen production by lactic acid fermentation. DNA analysis of the microbial community showed that the elevated pretreatment temperatures reduced the species diversity. (author)

  14. Development of an enumeration method for arsenic methylating bacteria from mixed culture samples.

    Science.gov (United States)

    Islam, S M Atiqul; Fukushi, Kensuke; Yamamoto, Kazuo

    2005-12-01

    Bacterial methylation of arsenic converts inorganic arsenic into volatile and non-volatile methylated species. It plays an important role in the arsenic cycle in the environment. Despite the potential environmental significance of AsMB, an assessment of their population size and activity remains unknown. This study has now established a protocol for enumeration of AsMB by means of the anaerobic-culture-tube, most probable number (MPN) method. Direct detection of volatile arsenic species is then done by GC-MS. This method is advantageous as it can simultaneously enumerate AsMB and acetate and formate-utilizing methanogens. The incubation time for this method was determined to be 6 weeks, sufficient time for AsMB growth.

  15. Transformation of carbon tetrachloride and chloroform by trichloroethene respiring anaerobic mixed cultures and supernatant.

    Science.gov (United States)

    Vickstrom, Kyle E; Azizian, Mohammad F; Semprini, Lewis

    2017-09-01

    Carbon tetrachloride (CT) and chloroform (CF) were transformed in batch reactor experiments conducted with anaerobic dechlorinating cultures and supernatant (ADC + S) harvested from continuous flow reactors. The Evanite (EV) and Victoria/Stanford (VS) cultures, capable of respiring trichloroethene (TCE), 1,2-cis-dichloroethene (cDCE), and vinyl chloride (VC) to ethene (ETH), were grown in continuous flow reactors receiving an influent feed of saturated TCE (10 mM; 60 mEq) and formate (45 mM; 90 mEq) but no CT or CF. Cells and supernatant were harvested from the chemostats and inoculated into batch reactors at the onset of each experiment. CT transformation was complete following first order kinetics with CF, DCM and CS 2 as the measurable transformation products, representing 20-40% of the original mass of CT, with CO 2 likely the unknown transformation product. CF was transformed to DCM and likely CO 2 at an order of magnitude rate lower than CT, while DCM was not further transformed. An analytical first order model including multiple key reactions effectively simulated CT transformation, product formation and transformation, and provided reasonable estimates of transformation rate coefficients. Biotic and abiotic treatments indicated that CT was mainly transformed via abiotic processes. However, the presence of live cells was associated with the transformation of CF to DCM. In biotic tests both TCE and CT were simultaneously transformed, with TCE transformed to ETH and approximately 15-53% less CF formed via CT transformation. A 14-day exposure to CF (CF max  = 1.4 μM) reduced all rates of chlorinated ethene respiration by a factor of 10 or greater. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Responses of neotropical mangrove seedlings grown in monoculture and mixed culture under treatments of hydroperiod and salinity

    Science.gov (United States)

    Cardona-Olarte, P.; Twilley, R.R.; Krauss, K.W.; Rivera-Monroy, V.

    2006-01-01

    We investigated the combined effects of salinity and hydroperiod on seedlings of Rhizophora mangle and Laguncularia racemosa grown under experimental conditions of monoculture and mixed culture by using a simulated tidal system. The objective was to test hypotheses relative to species interactions to either tidal or permanent flooding at salinities of 10 or 40 g/l. Four-month-old seedlings were experimentally manipulated under these environmental conditions in two types of species interactions: (1) seedlings of the same species were grown separately in containers from September 2000 to August 2001 to evaluate intraspecific response and (2) seedlings of each species were mixed in containers to evaluate interspecific, competitive responses from August 2002 to April 2003. Overall, L. racemosa was strongly sensitive to treatment combinations while R. mangle showed little effect. Most plant responses of L. racemosa were affected by both salinity and hydroperiod, with hydroperiod inducing more effects than salinity. Compared to R. mangle, L. racemosa in all treatment combinations had higher relative growth rate, leaf area ratio, specific leaf area, stem elongation, total length of branches, net primary production, and stem height. Rhizophora mangle had higher biomass allocation to roots. Species growth differentiation was more pronounced at low salinity, with few species differences at high salinity under permanent flooding. These results suggest that under low to mild stress by hydroperiod and salinity, L. racemosa exhibits responses that favor its competitive dominance over R. mangle. This advantage, however, is strongly reduced as stress from salinity and hydroperiod increase. ?? Springer 2006.

  17. The formal-informal patient payment mix in European countries. Governance, economics, culture or all of these?

    Science.gov (United States)

    Tambor, Marzena; Pavlova, Milena; Golinowska, Stanisława; Sowada, Christoph; Groot, Wim

    2013-12-01

    Cost-sharing for health care is high on the policy agenda in many European countries that struggle with deficits in their public budget. However, such policy often meets with public opposition, which might delay or even prevent its implementation. Increased reliance on patient payments may also have adverse equity effects, especially in countries where informal patient payments are widespread. The factors which might influence the presence of both, formal and informal payments can be found in economic, governance and cultural differences between countries. The aim of this paper is to review the formal-informal payment mix in Europe and to outline factors associated with this mix. We use quantitative analyses of macro-data for 35 European countries and a qualitative description of selected country experiences. The results suggest that the presence of obligatory cost-sharing for health care services is associated with governance factors, while informal patient payments are a multi-cause phenomenon. A consensus-based policy, supported by evidence and stakeholders' engagement, might contribute to a more sustainable patient payment policy. In some European countries, the implementation of cost-sharing requires policy actions to reduce other patient payment obligations, including measures to eliminate informal payments. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  18. Trace-gas metabolic versatility of the facultative methanotroph Methylocella silvestris

    Science.gov (United States)

    Crombie, Andrew T.; Murrell, J. Colin

    2014-06-01

    The climate-active gas methane is generated both by biological processes and by thermogenic decomposition of fossil organic material, which forms methane and short-chain alkanes, principally ethane, propane and butane. In addition to natural sources, environments are exposed to anthropogenic inputs of all these gases from oil and gas extraction and distribution. The gases provide carbon and/or energy for a diverse range of microorganisms that can metabolize them in both anoxic and oxic zones. Aerobic methanotrophs, which can assimilate methane, have been considered to be entirely distinct from utilizers of short-chain alkanes, and studies of environments exposed to mixtures of methane and multi-carbon alkanes have assumed that disparate groups of microorganisms are responsible for the metabolism of these gases. Here we describe the mechanism by which a single bacterial strain, Methylocella silvestris, can use methane or propane as a carbon and energy source, documenting a methanotroph that can utilize a short-chain alkane as an alternative to methane. Furthermore, during growth on a mixture of these gases, efficient consumption of both gases occurred at the same time. Two soluble di-iron centre monooxygenase (SDIMO) gene clusters were identified and were found to be differentially expressed during bacterial growth on these gases, although both were required for efficient propane utilization. This report of a methanotroph expressing an additional SDIMO that seems to be uniquely involved in short-chain alkane metabolism suggests that such metabolic flexibility may be important in many environments where methane and short-chain alkanes co-occur.

  19. Methylohalobius crimeensis gen. nov., sp. nov., a moderately halophilic, methanotrophic bacterium isolated from hypersaline lakes of Crimea.

    Science.gov (United States)

    Heyer, Jürgen; Berger, Ursula; Hardt, Martin; Dunfield, Peter F

    2005-09-01

    A novel genus and species are proposed for two strains of methanotrophic bacteria isolated from hypersaline lakes in the Crimean Peninsula of Ukraine. Strains 10Ki(T) and 4Kr are moderate halophiles that grow optimally at 1-1.5 M (5.8-8.7%, w/v) NaCl and tolerate NaCl concentrations from 0.2 M up to 2.5 M (1.2-15%). This optimum and upper limit are the highest for any methanotrophic bacterium known to date. The strains are Gram-negative, aerobic, non-pigmented, motile, coccoid to spindle-shaped bacteria that grow on methane or methanol only and utilize the ribulose monophosphate pathway for carbon assimilation. They are neutrophilic (growth occurs only in the range pH 6.5-7.5) and mesophilic (optimum growth occurs at 30 degrees C). On the basis of 16S rRNA gene sequence phylogeny, strains 10Ki(T) and 4Kr represent a type I methanotroph within the 'Gammaproteobacteria'. However, the 16S rRNA gene sequence displays <91.5 % identity to any public-domain sequence. The most closely related methanotrophic bacterium is the thermophilic strain HB. The DNA G+C content is 58.7 mol%. The major phospholipid fatty acids are 18:1omega7 (52-61%), 16:0 (22-23%) and 16:1omega7 (14-20%). The dominance of 18:1 over 16:0 and 16:1 fatty acids is unique among known type I methanotrophs. The data suggest that strains 10Ki(T) and 4Kr should be considered as belonging to a novel genus and species of type I methanotrophic bacteria, for which the name Methylohalobius crimeensis gen. nov., sp. nov. is proposed. Strain 10Ki(T) (=DSM 16011(T)=ATCC BAA-967(T)) is the type strain.

  20. Activation of NK Cells in Mixed Cultures of Wharton's Jelly Mesenchymal Stromal Cells and Peripheral Blood Lymphocytes.

    Science.gov (United States)

    Svirshchevskaya, E V; Poltavtsev, A M; Os'mak, G Zh; Poltavtseva, R A

    2018-01-01

    Mesenchymal stromal cells possess immunosuppressive properties that might be used for the therapy of inflammatory diseases of various geneses. The effects of mesenchymal stromal cells depend on their lifetime in the recipient tissues. During heterologous transplantation, mesenchymal stromal cells are eliminated by NK cells. We studied NK cell formation in mixed cultures of Wharton's jelly mesenchymal stromal cells and peripheral blood lymphocytes from an autologous donor. Lymphocytes were activated by a mitogen or IL-2. The lifetime of mesenchymal stromal cells was estimated by MTT test. Cytotoxic activity and phenotype of NK cells were evaluated by flow cytometry. It was found that activation of NK cells depended on IL-2 and was registered on day 2 of incubation with IL-2. In cultures with mitogen-activated lymphocytes, cytotoxicity was observed after 5-6 days. Cytotoxicity of NK correlated with significant decrease in CD16+ and increase in CD56+ NK and with reduction of mesenchymal stromal cell viability. Thus, the main mechanism of elimination of mesenchymal stromal cells is cytotoxicity of NK cells that depended on IL-2 production.

  1. Characterization of culturable yeast species associating with whole crop corn and total mixed ration silage.

    Science.gov (United States)

    Wang, Huili; Hao, Wei; Ning, Tingting; Zheng, Mingli; Xu, Chuncheng

    2018-02-01

    This study investigated the association of yeast species with improved aerobic stability of total mixed ration (TMR) silages with prolonged ensiling, and clarified the characteristics of yeast species and their role during aerobic deterioration. Whole crop corn (WCC) silages and TMR silages formulated with WCC were ensiled for 7, 14, 28, and 56 d and used for an aerobic stability test. Predominant yeast species were isolated from different periods and identified by sequencing analyses of the 26S rRNA gene D1/D2 domain. Characteristics (assimilation and tolerance) of the yeast species and their role during aerobic deterioration were investigated. In addition to species of Candida glabrata and Pichia kudriavzevii ( P. kudriavzevii ) previously isolated in WCC and TMR, Pichia manshurica ( P. manshurica ), Candida ethanolica ( C. ethanolica ), and Zygosaccharomyces bailii ( Z. bailii ) isolated at great frequency during deterioration, were capable of assimilating lactic or acetic acid and tolerant to acetic acid and might function more in deteriorating TMR silages at early fermentation (7 d and 14 d). With ensiling prolonged to 28 d, silages became more (p<0.01) stable when exposed to air, coinciding with the inhibition of yeast to below the detection limit. Species of P. manshurica that were predominant in deteriorating WCC silages were not detectable in TMR silages. In addition, the predominant yeast species of Z. bailii in deteriorating TMR silages at later fermentation (28 d and 56 d) were not observed in both WCC and WCC silages. The inhibition of yeasts, particularly P. kudriavzevii , probably account for the improved aerobic stability of TMR silages at later fermentation. Fewer species seemed to be involved in aerobic deterioration of silages at later fermentation and Z. bailii was most likely to initiate the aerobic deterioration of TMR silages at later fermentation. The use of WCC in TMR might not influence the predominant yeast species during aerobic

  2. Characterization of culturable yeast species associating with whole crop corn and total mixed ration silage

    Directory of Open Access Journals (Sweden)

    Huili Wang

    2018-02-01

    Full Text Available Objective This study investigated the association of yeast species with improved aerobic stability of total mixed ration (TMR silages with prolonged ensiling, and clarified the characteristics of yeast species and their role during aerobic deterioration. Methods Whole crop corn (WCC silages and TMR silages formulated with WCC were ensiled for 7, 14, 28, and 56 d and used for an aerobic stability test. Predominant yeast species were isolated from different periods and identified by sequencing analyses of the 26S rRNA gene D1/D2 domain. Characteristics (assimilation and tolerance of the yeast species and their role during aerobic deterioration were investigated. Results In addition to species of Candida glabrata and Pichia kudriavzevii (P. kudriavzevii previously isolated in WCC and TMR, Pichia manshurica (P. manshurica, Candida ethanolica (C. ethanolica, and Zygosaccharomyces bailii (Z. bailii isolated at great frequency during deterioration, were capable of assimilating lactic or acetic acid and tolerant to acetic acid and might function more in deteriorating TMR silages at early fermentation (7 d and 14 d. With ensiling prolonged to 28 d, silages became more (p<0.01 stable when exposed to air, coinciding with the inhibition of yeast to below the detection limit. Species of P. manshurica that were predominant in deteriorating WCC silages were not detectable in TMR silages. In addition, the predominant yeast species of Z. bailii in deteriorating TMR silages at later fermentation (28 d and 56 d were not observed in both WCC and WCC silages. Conclusion The inhibition of yeasts, particularly P. kudriavzevii, probably account for the improved aerobic stability of TMR silages at later fermentation. Fewer species seemed to be involved in aerobic deterioration of silages at later fermentation and Z. bailii was most likely to initiate the aerobic deterioration of TMR silages at later fermentation. The use of WCC in TMR might not influence the predominant

  3. Cultural responses to pain in UK children of primary school age: a mixed-methods study.

    Science.gov (United States)

    Azize, Pary M; Endacott, Ruth; Cattani, Allegra; Humphreys, Ann

    2014-06-01

    Pain-measurement tools are often criticized for not addressing the influence of culture and ethnicity on pain. This study examined how children who speak English as a primary or additional language discuss pain. Two methods were used in six focus group interviews with 34 children aged 4-7 years: (i) use of drawings from the Pediatric Pain Inventory to capture the language used by children to describe pain; and (ii) observation of the children's placing of pain drawings on red/amber/green paper to denote perceived severity of pain. The findings demonstrated that children with English as an additional language used less elaborate language when talking about pain, but tended to talk about the pictures prior to deciding where they should be placed. For these children, there was a positive significant relationship between language, age, and length of stay in the UK. The children's placement of pain drawings varied according to language background, sex, and age. The findings emphasize the need for sufficient time to assess pain adequately in children who do not speak English as a first language. © 2013 Wiley Publishing Asia Pty Ltd.

  4. Rapid paper disk test for identification of Helicobacter pylori in mixed cultures of gerbil gastric homogenates.

    Science.gov (United States)

    Castillo-Juarez, Israel; Rangel-Vega, Adrian; Romero, Irma

    2010-10-01

    A method denominated rapid paper disk test (RPDT) was developed to identify H. pylori colonies in complex cultures obtained from gerbil gastric homogenates. Identification is based on a characteristic reaction pattern (RP) for H. pylori colonies given by the combination of the urease-oxidase activities on a paper disk. Compared to the RPs obtained from gerbil's intestinal tract isolated bacteria, H. pylori RP is completely distinguishable, even from those of bacteria that share one or both activities as are Aerococcus urinae, Bacillus sphaericus, Bacillus brevis, Corynebacterium pseudogenitalium, and Staphylococcus simulans, as well as from those produced by collection strains Proteus vulgaris and Pseudomonas aeruginosa. This method allows the practical quantification of H. pylori colonies in highly contaminated plates. RPDT has the following advantages over other methodologies that use indicators in the medium: it employs two of the three routinely used H. pylori biochemical identification tests, the reagents do not interfere with bacterial viability, there are no restrictions in relation to the medium used, and it is a simple, fast, and low-cost method. Copyright © 2010 Elsevier B.V. All rights reserved.

  5. Seeing Mixed Emotions: The Specificity of Emotion Perception From Static and Dynamic Facial Expressions Across Cultures.

    Science.gov (United States)

    Fang, Xia; Sauter, Disa A; Van Kleef, Gerben A

    2018-01-01

    Although perceivers often agree about the primary emotion that is conveyed by a particular expression, observers may concurrently perceive several additional emotions from a given facial expression. In the present research, we compared the perception of two types of nonintended emotions in Chinese and Dutch observers viewing facial expressions: emotions which were morphologically similar to the intended emotion and emotions which were morphologically dissimilar to the intended emotion. Findings were consistent across two studies and showed that (a) morphologically similar emotions were endorsed to a greater extent than dissimilar emotions and (b) Chinese observers endorsed nonintended emotions more than did Dutch observers. Furthermore, the difference between Chinese and Dutch observers was more pronounced for the endorsement of morphologically similar emotions than of dissimilar emotions. We also obtained consistent evidence that Dutch observers endorsed nonintended emotions that were congruent with the preceding expressions to a greater degree. These findings suggest that culture and morphological similarity both influence the extent to which perceivers see several emotions in a facial expression.

  6. Seeing Mixed Emotions: The Specificity of Emotion Perception From Static and Dynamic Facial Expressions Across Cultures

    Science.gov (United States)

    Fang, Xia; Sauter, Disa A.; Van Kleef, Gerben A.

    2017-01-01

    Although perceivers often agree about the primary emotion that is conveyed by a particular expression, observers may concurrently perceive several additional emotions from a given facial expression. In the present research, we compared the perception of two types of nonintended emotions in Chinese and Dutch observers viewing facial expressions: emotions which were morphologically similar to the intended emotion and emotions which were morphologically dissimilar to the intended emotion. Findings were consistent across two studies and showed that (a) morphologically similar emotions were endorsed to a greater extent than dissimilar emotions and (b) Chinese observers endorsed nonintended emotions more than did Dutch observers. Furthermore, the difference between Chinese and Dutch observers was more pronounced for the endorsement of morphologically similar emotions than of dissimilar emotions. We also obtained consistent evidence that Dutch observers endorsed nonintended emotions that were congruent with the preceding expressions to a greater degree. These findings suggest that culture and morphological similarity both influence the extent to which perceivers see several emotions in a facial expression. PMID:29386689

  7. Essential oils have different effects on human pathogenic and commensal bacteria in mixed faecal fermentations compared with pure cultures.

    Science.gov (United States)

    Thapa, Dinesh; Louis, Petra; Losa, Riccardo; Zweifel, Béatrice; Wallace, R John

    2015-02-01

    A static batch culture system inoculated with human faeces was used to determine the influence of essential oil compounds (EOCs) on mixed faecal microbiota. Bacteria were quantified using quantitative PCR of 16S rRNA genes. Incubation for 24 h of diluted faeces from six individuals caused enrichment of Bifidobacterium spp., but proportions of other major groups were unaffected. Thymol and geraniol at 500 p.p.m. suppressed total bacteria, resulting in minimal fermentation. Thymol at 100 p.p.m. had no effect, nor did eugenol or nerolidol at 100 or 500 p.p.m. except for a slight suppression of Eubacterium hallii. Methyl isoeugenol at 100 or 500 p.p.m. suppressed the growth of total bacteria, accompanied by a large fall in the molar proportion of propionate formed. The relative abundance of Faecalibacterium prausnitzii was unaffected except with thymol at 500 p.p.m. The ability of EOCs to control numbers of the pathogen Clostridium difficile was investigated in a separate experiment, in which the faecal suspensions were amended by the addition of pure culture of C. difficile. Numbers of C. difficile were suppressed by thymol and methyl isoeugenol at 500 p.p.m. and to a lesser extent at 100 p.p.m. Eugenol and geraniol gave rather similar suppression of C. difficile numbers at both 100 and 500 p.p.m. Nerolidol had no significant effect. It was concluded from these and previous pure-culture experiments that thymol and geraniol at around 100 p.p.m. could be effective in suppressing pathogens in the small intestine, with no concern for beneficial commensal colonic bacteria in the distal gut. © 2015 The Authors.

  8. Production of L-lactic acid from Cassava peel wastes using single and mixed cultures of Rhizopus oligosporus and Lactobacillus plantarum

    Directory of Open Access Journals (Sweden)

    Nwokoro Ogbonnaya

    2014-01-01

    Full Text Available Production of L-lactic acid using cultures of Rhizopus oligosporus and Lactobacillus plantarum was investigated. Cassava peels were hydrolyzed by boiling for 1 h in either NaOH or HCl solutions followed by neutralization to a pH of 6.2. Reducing sugar produced from the hydrolysates increased with increasing concentrations of alkali or acid. Samples hydrolyzed with HCl produced a maximum reducing sugar concentration of 402 mg/g substrate while alkali hydrolyzed samples produced a maximum reducing sugar concentration of 213 mg/g substrate. Hydrolysates were amended with 0.5% ammonium sulphate solution and inoculated with either single or mixed cultures of Rhizopus oligosporus and Lactobacillus plantarum and incubated for 48 h for lactic acid production. The best lactic acid production of 50.2 g/100g substrate was observed in a mixed culture fermentation of acid hydrolyzed peels. Mixed culture fermentation of alkali hydrolyzed peels produced a maximum lactic acid concentration of 36.4 g/100g substrate. Un hydrolyzed cassava peels inoculated with a mixed culture of the microorganisms produced only 4.6 g/100g substrate. This work reports an efficient use of cassava peels for bio-product formation through microbial fermentation.

  9. Lactococcus lactis Diversity in Undefined Mixed Dairy Starter Cultures as Revealed by Comparative Genome Analyses and Targeted Amplicon Sequencing of epsD.

    Science.gov (United States)

    Frantzen, Cyril A; Kleppen, Hans Petter; Holo, Helge

    2018-02-01

    Undefined mesophilic mixed (DL) starter cultures are used in the production of continental cheeses and contain unknown strain mixtures of Lactococcus lactis and leuconostocs. The choice of starter culture affects the taste, aroma, and quality of the final product. To gain insight into the diversity of Lactococcus lactis strains in starter cultures, we whole-genome sequenced 95 isolates from three different starter cultures. Pan-genomic analyses, which included 30 publically available complete genomes, grouped the strains into 21 L. lactis subsp . lactis and 28 L. lactis subsp. cremoris lineages. Only one of the 95 isolates grouped with previously sequenced strains, and the three starter cultures showed no overlap in lineage distributions. The culture diversity was assessed by targeted amplicon sequencing using purR , a core gene, and epsD , present in 93 of the 95 starter culture isolates but absent in most of the reference strains. This enabled an unprecedented discrimination of starter culture Lactococcus lactis and revealed substantial differences between the three starter cultures and compositional shifts during the cultivation of cultures in milk. IMPORTANCE In contemporary cheese production, standardized frozen seed stock starter cultures are used to ensure production stability, reproducibility, and quality control of the product. The dairy industry experiences significant disruptions of cheese production due to phage attacks, and one commonly used countermeasure to phage attack is to employ a starter rotation strategy, in which two or more starters with minimal overlap in phage sensitivity are used alternately. A culture-independent analysis of the lactococcal diversity in complex undefined starter cultures revealed large differences between the three starter cultures and temporal shifts in lactococcal composition during the production of bulk starters. A better understanding of the lactococcal diversity in starter cultures will enable the development of

  10. Use of a mixed culture strategy to isolate halophilic bacteria with antibacterial and cytotoxic activity from the Manaure solar saltern in Colombia.

    Science.gov (United States)

    Conde-Martínez, Natalia; Acosta-González, Alejandro; Díaz, Luis E; Tello, Edisson

    2017-12-08

    Water evaporation in solar salterns creates salinity gradients that promote the adaptation of microbial species to different salinities. This competitive habitat challenges the metabolic capabilities of microorganisms and promotes alterations in their production of secondary metabolites. Thus, solar salterns are a potentially important source of new natural products. In Colombia, the most important and representative solar saltern is located in Manaure (La Guajira) in the north of Colombia. The aim of this study was to develop an alternative screening strategy to select halophilic bacteria as producers of bioactive compounds from mixed microbial cultures rather than individual environmental isolates. Brine and sediment samples from different ponds (across a salinity gradient) were inoculated in seven different culture media to grow bacteria and archaea, allowing for a total of 40 different mixed cultures. An organic extract from each mixed culture was obtained and tested against multidrug resistant pathogens, including Klebsiella pneumoniae, vancomycin-resistant Enterococcus faecium, methicillin-resistant Staphylococcus aureus and Bacillus subtilis. In addition, the extracts were tested against two human cancer cell lines, cervical adenocarcinoma (SiHa) and lung carcinoma (A-549). Twenty-four of the forty extracts from mixed cultures obtained from brine and sediment samples from the Manaure solar saltern showed antibacterial activity against Bacillus subtilis. Two extracts, referred to as A1SM3-29 and A1SM3-36, were also active against a methicillin-resistant Staphylococcus aureus, with the latter extract also showing slight cytotoxic activity against the assayed human lung cancer cell line. From this mixed culture, nine isolates were cultivated, and their extracts were tested against the same pathogens, resulting in the identification of a Vibrio sp. strain (A1SM3-36-8) with antimicrobial activity that was similar to that observed for the mixed culture extract

  11. Effect of bacterial components of mixed culture supernatants of planktonic and biofilm Pseudomonas aeruginosa with commensal Escherichia coli on the neutrophil response in vitro.

    Science.gov (United States)

    Maslennikova, Irina L; Kuznetsova, Marina V; Nekrasova, Irina V; Shirshev, Sergei V

    2017-11-30

    Pseudomonas aeruginosa (PA) responsible for acute and chronic infections often forms a well-organized bacterial population with different microbial species including commensal strains of Escherichia coli. Bacterial extracellular components of mixed culture can modulate the influence of bacteria on the neutrophil functions. The objective of this study was to compare the effect of pyocyanin, pyoverdine, LPS, exopolysaccharide of single species and mixed culture supernatants of PA strains and E. coli K12 on microbicidal, secretory activity of human neutrophils in vitro. Bacterial components of E. coli K12 in mixed supernatants with 'biofilm' PA strains (PA ATCC, PA BALG) enhanced short-term microbicidal mechanisms and inhibited neutrophil secretion delayed in time. The influence of 'planktonic' PA (PA 9-3) exometabolites in mixed culture is almost mimicked by E. coli K12 effect on functional neutrophil changes. This investigation may help to understand some of the mechanisms of neutrophil response to mixed infections of different PA with other bacteria species. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. Application of the NDHA model to describe N2O dynamics in activated sludge mixed culture biomass

    DEFF Research Database (Denmark)

    Domingo-Felez, Carlos; Smets, Barth F.

    A pseudo-mechanistic model describing three biological nitric oxide (NO) and nitrous oxide (N2O) production pathways was calibrated for an activated sludge mixed culture biomass treating municipal wastewater with laboratory-scale experiments. The model (NDHA) comprehensively describes N2O produci...

  13. MODELING OF MIXED CHEMOSTAT CULTURES OF AN AEROBIC BACTERIUM, COMAMONAS-TESTOSTERONI, AND AN ANAEROBIC BACTERIUM, VEILLONELLA-ALCALESCENS - COMPARISON WITH EXPERIMENTAL-DATA

    NARCIS (Netherlands)

    GERRITSE, J; SCHUT, F; GOTTSCHAL, JC

    A mathematical model of mixed chemostat cultures of the obligately aerobic bacterium Comamonas testosteroni and the anaerobic bacterium Veillonella alcalescens grown under dual limitation Of L-lactate and oxygen was constructed. The model was based on Michaelis-Menten-type kinetics for the

  14. Investigation of the bacteriophage community in induced lysates of undefined mesophilic mixed-strain DL-cultures using classical and metagenomic approaches

    DEFF Research Database (Denmark)

    Muhammed, Musemma K.; Olsen, Mette L.; Kot, Witold

    2018-01-01

    To investigate the notion that starter cultures can be a reservoir of bacteriophages (phages) in the dairy environment, strains of three DL-starters (undefined mesophilic mixed-strain starters containing Lactococcus lactis subsp. lactis biovar. diacetylactis and Leuconostoc species) were selected...

  15. Motivating Teachers towards Expertise Development: A Mixed-Methods Study of the Relationships between School Culture, Internal Factors, and State of Flow

    Science.gov (United States)

    Mayeaux, Amanda Shuford

    2013-01-01

    The purpose of this sequential mixed-methods research was to discover the impact school culture, internal factors, and the state of flow has upon motivating a teacher to develop teaching expertise. This research was designed to find answers concerning why and how individual teachers can nurture their existing internal factors to increase their…

  16. Column study of enhanced Cr(VI) removal and longevity by coupled abiotic and biotic processes using Fe0 and mixed anaerobic culture

    DEFF Research Database (Denmark)

    Zhong, Jiawei; Yin, Weizhao; Li, Yongtao

    2017-01-01

    In this study, Fe(0) and mixed anaerobic culture were integrated in one column to investigate the coupled abiotic and biotic effects on hexa-valent chromium (Cr(VI)) removal and column longevity with an abiotic Fe(0) column in the control experiments. According to the breakthrough study, a slower...

  17. High Throughput Sequencing to Detect Differences in Methanotrophic Methylococcaceae and Methylocystaceae in Surface Peat, Forest Soil, and Sphagnum Moss in Cranesville Swamp Preserve, West Virginia, USA

    Science.gov (United States)

    Lau, Evan; Nolan, Edward J.; Dillard, Zachary W.; Dague, Ryan D.; Semple, Amanda L.; Wentzell, Wendi L.

    2015-01-01

    Northern temperate forest soils and Sphagnum-dominated peatlands are a major source and sink of methane. In these ecosystems, methane is mainly oxidized by aerobic methanotrophic bacteria, which are typically found in aerated forest soils, surface peat, and Sphagnum moss. We contrasted methanotrophic bacterial diversity and abundances from the (i) organic horizon of forest soil; (ii) surface peat; and (iii) submerged Sphagnum moss from Cranesville Swamp Preserve, West Virginia, using multiplex sequencing of bacterial 16S rRNA (V3 region) gene amplicons. From ~1 million reads, >50,000 unique OTUs (Operational Taxonomic Units), 29 and 34 unique sequences were detected in the Methylococcaceae and Methylocystaceae, respectively, and 24 potential methanotrophs in the Beijerinckiaceae were also identified. Methylacidiphilum-like methanotrophs were not detected. Proteobacterial methanotrophic bacteria constitute Sphagnum moss) or co-occurred in both Sphagnum moss and peat. This study provides insights into the structure of methanotrophic communities in relationship to habitat type, and suggests that peat and Sphagnum moss can influence methanotroph community structure and biogeography. PMID:27682082

  18. Biodegradation of Low-Density Polyethylene (LDPE) by Mixed Culture of Lysinibacillus xylanilyticus and Aspergillus niger in Soil

    Science.gov (United States)

    Esmaeili, Atefeh; Pourbabaee, Ahmad Ali; Alikhani, Hossein Ali; Shabani, Farzin; Esmaeili, Ensieh

    2013-01-01

    In this study, two strains of Aspergillus sp. and Lysinibacillus sp. with remarkable abilities to degrade low-density polyethylene (LDPE) were isolated from landfill soils in Tehran using enrichment culture and screening procedures. The biodegradation process was performed for 126 days in soil using UV- and non-UV-irradiated pure LDPE films without pro-oxidant additives in the presence and absence of mixed cultures of selected microorganisms. The process was monitored by measuring the microbial population, the biomass carbon, pH and respiration in the soil, and the mechanical properties of the films. The carbon dioxide measurements in the soil showed that the biodegradation in the un-inoculated treatments were slow and were about 7.6% and 8.6% of the mineralisation measured for the non-UV-irradiated and UV-irradiated LDPE, respectively, after 126 days. In contrast, in the presence of the selected microorganisms, biodegradation was much more efficient and the percentages of biodegradation were 29.5% and 15.8% for the UV-irradiated and non-UV-irradiated films, respectively. The percentage decrease in the carbonyl index was higher for the UV-irradiated LDPE when the biodegradation was performed in soil inoculated with the selected microorganisms. The percentage elongation of the films decreased during the biodegradation process. The Fourier transform infra-red (FT-IR), x-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to determine structural, morphological and surface changes on polyethylene. These analyses showed that the selected microorganisms could modify and colonise both types of polyethylene. This study also confirmed the ability of these isolates to utilise virgin polyethylene without pro-oxidant additives and oxidation pretreatment, as the carbon source. PMID:24086254

  19. Biodegradation of low-density polyethylene (LDPE by mixed culture of Lysinibacillus xylanilyticus and Aspergillus niger in soil.

    Directory of Open Access Journals (Sweden)

    Atefeh Esmaeili

    Full Text Available In this study, two strains of Aspergillus sp. and Lysinibacillus sp. with remarkable abilities to degrade low-density polyethylene (LDPE were isolated from landfill soils in Tehran using enrichment culture and screening procedures. The biodegradation process was performed for 126 days in soil using UV- and non-UV-irradiated pure LDPE films without pro-oxidant additives in the presence and absence of mixed cultures of selected microorganisms. The process was monitored by measuring the microbial population, the biomass carbon, pH and respiration in the soil, and the mechanical properties of the films. The carbon dioxide measurements in the soil showed that the biodegradation in the un-inoculated treatments were slow and were about 7.6% and 8.6% of the mineralisation measured for the non-UV-irradiated and UV-irradiated LDPE, respectively, after 126 days. In contrast, in the presence of the selected microorganisms, biodegradation was much more efficient and the percentages of biodegradation were 29.5% and 15.8% for the UV-irradiated and non-UV-irradiated films, respectively. The percentage decrease in the carbonyl index was higher for the UV-irradiated LDPE when the biodegradation was performed in soil inoculated with the selected microorganisms. The percentage elongation of the films decreased during the biodegradation process. The Fourier transform infra-red (FT-IR, x-ray diffraction (XRD and scanning electron microscopy (SEM were used to determine structural, morphological and surface changes on polyethylene. These analyses showed that the selected microorganisms could modify and colonise both types of polyethylene. This study also confirmed the ability of these isolates to utilise virgin polyethylene without pro-oxidant additives and oxidation pretreatment, as the carbon source.

  20. Palmitoylethanolamide exerts neuroprotective effects in mixed neuroglial cultures and organotypic hippocampal slices via peroxisome proliferator-activated receptor-α

    Directory of Open Access Journals (Sweden)

    Scuderi Caterina

    2012-03-01

    Full Text Available Abstract Background In addition to cytotoxic mechanisms directly impacting neurons, β-amyloid (Aβ-induced glial activation also promotes release of proinflammatory molecules that may self-perpetuate reactive gliosis and damage neighbouring neurons, thus amplifying neuropathological lesions occurring in Alzheimer's disease (AD. Palmitoylethanolamide (PEA has been studied extensively for its anti-inflammatory, analgesic, antiepileptic and neuroprotective effects. PEA is a lipid messenger isolated from mammalian and vegetable tissues that mimics several endocannabinoid-driven actions, even though it does not bind to cannabinoid receptors. Some of its pharmacological properties are considered to be dependent on the expression of peroxisome proliferator-activated receptors-α (PPARα. Findings In the present study, we evaluated the effect of PEA on astrocyte activation and neuronal loss in models of Aβ neurotoxicity. To this purpose, primary rat mixed neuroglial co-cultures and organotypic hippocampal slices were challenged with Aβ1-42 and treated with PEA in the presence or absence of MK886 or GW9662, which are selective PPARα and PPARγ antagonists, respectively. The results indicate that PEA is able to blunt Aβ-induced astrocyte activation and, subsequently, to improve neuronal survival through selective PPARα activation. The data from organotypic cultures confirm that PEA anti-inflammatory properties implicate PPARα mediation and reveal that the reduction of reactive gliosis subsequently induces a marked rebound neuroprotective effect on neurons. Conclusions In line with our previous observations, the results of this study show that PEA treatment results in decreased numbers of infiltrating astrocytes during Aβ challenge, resulting in significant neuroprotection. PEA could thus represent a promising pharmacological tool because it is able to reduce Aβ-evoked neuroinflammation and attenuate its neurodegenerative consequences.

  1. Selection of Type I and Type II Methanotrophic Proteobacteria in a Fluidized Bed Reactor under Non-Sterile Conditions

    Science.gov (United States)

    2011-08-01

    equipped with a thermal con- ductivity detector (TCD) with a CTR1 column ( Alltech Associates Inc., Deerfield, IL) with He as carrier gas. The injection...grow at this pH (Bowman, 2006). Ama- ral and Knowles (1995) reported that Type II methanotrophs had a competitive advantage when oxygen was limited and

  2. Hydrology is reflected in the functioning and community composition of methanotrophs in the littoral wetland of a boreal lake

    NARCIS (Netherlands)

    Siljanen, H.M.P.; Saari, A.; Krause, S.; Lensu, A.; Abell, G.C.J.; Bodrossy, L.; Bodelier, P.L.E.; Martikainen, P.J.

    2011-01-01

    In lake ecosystems a major proportion of methane emissions originate from the littoral zone which can have a great spatial variability in hydrology, soil quality and vegetation. Hitherto, spatial heterogeneity and the effects it has on functioning and diversity of methanotrophs in littoral wetlands

  3. Methanotrophic activity and diversity in different Sphagnum magellanicum dominated habitats in the southernmost peat bogs of Patagonia

    NARCIS (Netherlands)

    Kip, N.; Fritz, C.; Langelaan, E. S.; Pan, Y.; Bodrossy, L.; Pancotto, V.; Jetten, M. S. M.; Smolders, A. J. P.; den Camp, H. J. M. Op

    2012-01-01

    Sphagnum peatlands are important ecosystems in the methane cycle. Methanotrophs living inside the dead hyaline cells or on the Sphagnum mosses are able to act as a methane filter and thereby reduce methane emissions. We investigated in situ methane concentrations and the corresponding activity and

  4. Effect of nitrogen source on methanol oxidation and genetic diversity of methylotrophic mixed cultures enriched from pulp and paper mill biofilms.

    Science.gov (United States)

    Babbitt, Callie W; Lindner, Angela S

    2011-04-01

    Methanol-oxidizing bacteria may play an important role in the development and use of biological treatment systems for the removal of methanol from industrial effluents. Optimization of methanol degradation potential in such systems is contingent on availability of nutrients, such as nitrogen, in the most favorable form and concentration. To that end, this study examined the variation in growth, methanol degradation, and bacterial diversity of two mixed methylotrophic cultures that were provided nitrogen either as ammonium or nitrate and in three different concentrations. Methanol-degrading cultures were enriched from biofilms sampled at a pulp and paper mill and grown in liquid batch culture with methanol as the only carbon source and either ammonium or nitrate as the only added nitrogen source. Results indicate that growth and methanol removal of the mixed cultures increase directly with increased nitrogen, added in either form. However, methanol removal and bacterial diversity, as observed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) methods, were higher when using nitrate as the nitrogen source for enrichment and growth, rather than ammonium. Based on results described here, nitrate may potentially be a better nitrogen source when enriching or working with mixed methylotrophic cultures, and possibly more effective when used as a nutrient addition to biofilters.

  5. Cocaine induces a mixed lysosomal lipidosis in cultured fibroblasts, by inactivation of acid sphingomyelinase and inhibition of phospholipase A1

    International Nuclear Information System (INIS)

    Nassogne, Marie-Cecile; Lizarraga, Chantal; N'Kuli, Francisca; Van Bambeke, Francoise; Van Binst, Roger; Wallemacq, Pierre; Tulkens, Paul M.; Mingeot-Leclercq, Marie-Paule; Levade, Thierry; Courtoy, Pierre J.

    2004-01-01

    This paper reports that cocaine may induce a lysosomal storage disorder. Indeed, culture of Rat-1 fibroblasts with 250-500 μM cocaine induced after 2-3 days a major accumulation in lysosomes of electron-dense lamellar structures. By subcellular fractionation, this was reflected by a selective decrease of the buoyant density of several lysosomal enzymes, indicating lysosomal lipid overload. Biochemical analysis confirmed an increased cellular content of major phospholipids and sphingomyelin, but not of cholesterol. Cocaine, a membrane-permeant weak base, is concentrated by acidotropic sequestration, because its accumulation was abrogated by the proton ionophore, monensin and the vacuolar ATPase inhibitor, bafilomycin A 1 . At its estimated lysosomal concentration, cocaine almost completely inhibited phospholipase A 1 activity on liposomes. Cell incubation with cocaine, but not with its inactive metabolite, benzoylecgonine, rapidly inactivated acid sphingomyelinase, as reflected by a 10-fold decrease in V max with identical K m . Acid sphingomyelinase inactivation was fully prevented by the thiol proteinases inhibitors, leupeptin and E64, indicating that cocaine induces selective sphingomyelinase proteolysis. Upon cocaine removal, acid sphingomyelinase activity was rapidly restored, pointing to its fast turnover. In contrast, the cellular content of several other lysosomal hydrolases was increased up to 2-fold. Together, these data show that acidotropic accumulation of cocaine in lysosomes rapidly inhibits acid phospholipase A 1 and inactivates acid sphingomyelinase, which can explain induction of a mixed lysosomal lipidosis

  6. Protocol for the Differentiation of Human Induced Pluripotent Stem Cells into Mixed Cultures of Neurons and Glia for Neurotoxicity Testing.

    Science.gov (United States)

    Pistollato, Francesca; Canovas-Jorda, David; Zagoura, Dimitra; Price, Anna

    2017-06-09

    Human pluripotent stem cells can differentiate into various cell types that can be applied to human-based in vitro toxicity assays. One major advantage is that the reprogramming of somatic cells to produce human induced pluripotent stem cells (hiPSCs) avoids the ethical and legislative issues related to the use of human embryonic stem cells (hESCs). HiPSCs can be expanded and efficiently differentiated into different types of neuronal and glial cells, serving as test systems for toxicity testing and, in particular, for the assessment of different pathways involved in neurotoxicity. This work describes a protocol for the differentiation of hiPSCs into mixed cultures of neuronal and glial cells. The signaling pathways that are regulated and/or activated by neuronal differentiation are defined. This information is critical to the application of the cell model to the new toxicity testing paradigm, in which chemicals are assessed based on their ability to perturb biological pathways. As a proof of concept, rotenone, an inhibitor of mitochondrial respiratory complex I, was used to assess the activation of the Nrf2 signaling pathway, a key regulator of the antioxidant-response-element-(ARE)-driven cellular defense mechanism against oxidative stress.

  7. Mitigation of soil N2O emission by inoculation with a mixed culture of indigenous Bradyrhizobium diazoefficiens

    Science.gov (United States)

    Akiyama, Hiroko; Hoshino, Yuko Takada; Itakura, Manabu; Shimomura, Yumi; Wang, Yong; Yamamoto, Akinori; Tago, Kanako; Nakajima, Yasuhiro; Minamisawa, Kiwamu; Hayatsu, Masahito

    2016-09-01

    Agricultural soil is the largest source of nitrous oxide (N2O), a greenhouse gas. Soybean is an important leguminous crop worldwide. Soybean hosts symbiotic nitrogen-fixing soil bacteria (rhizobia) in root nodules. In soybean ecosystems, N2O emissions often increase during decomposition of the root nodules. Our previous study showed that N2O reductase can be used to mitigate N2O emission from soybean fields during nodule decomposition by inoculation with nosZ++ strains [mutants with increased N2O reductase (N2OR) activity] of Bradyrhizobium diazoefficiens. Here, we show that N2O emission can be reduced at the field scale by inoculation with a mixed culture of indigenous nosZ+ strains of B. diazoefficiens USDA110 group isolated from Japanese agricultural fields. Our results also suggested that nodule nitrogen is the main source of N2O production during nodule decomposition. Isolating nosZ+ strains from local soybean fields would be more applicable and feasible for many soybean-producing countries than generating mutants.

  8. The sedimentation of mixed cultures used in the treatment of effluents generated from terrestrial fuel distribution terminals

    International Nuclear Information System (INIS)

    Vieira, R.B.; Vieira, P.A.; Ribeiro, E.J.; Cardoso, V.L.

    2010-01-01

    This study evaluated the use of coagulants (ferric chloride and aluminium sulphate) and an anionic polyelectrolyte (polyacrylamide) in the settling of a mixed culture (C 1 ), which was used for the biodegradation of hydrocarbons present in effluent of fuel distribution terminals contaminated with diesel oil and gasoline. In preliminary investigations conducted in jar tests, the optimal concentrations of coagulant were obtained for further studies. After preliminary tests, biodegradation was evaluated in a central composite design (CCD) with varying concentrations of ferric chloride and polyelectrolyte. Ferric chloride and polyelectrolyte concentrations ranged from 77.9 to 422.12 mg/L and 0.0 to 3.2 mg/L, respectively. The responses monitored in CCD experiments included the sludge volume index (SVI), turbidity, and specific rate of oxygen uptake (SOUR), where values of 100 mL/g, 840 nephelometric turbidity unit (NTU) and 58 mg O 2 /g h, respectively, were obtained. Subsequently, biodegradation was monitored in a sequencing batch reactor (SBR). The results indicated that within five cycles, total petroleum hydrocarbon (TPH) removal increased from 75 ± 1.0% to 79 ± 0.5%, while the volatile suspended solids (VSS) increased from 1300 to 2500 mg/L.

  9. Genetic Algorithmic Optimization of PHB Production by a Mixed Culture in an Optimally Dispersed Fed-batch Bioreactor

    Directory of Open Access Journals (Sweden)

    Pratap R. Patnaik

    2009-10-01

    Full Text Available Poly-β-hydroxybutyrate (PHB is an energy-storage polymer whose properties are similar to those of chemical polymers such as polyethylene and polypropylene. Moreover, PHB is biodegradable, absorbed by human tissues and less energy-consuming than synthetic polymers. Although Ralstonia eutropha is widely used to synthesize PHB, it is inefficient in utilizing glucose and similar sugars. Therefore a co-culture of R. eutropha and Lactobacillus delbrueckii is preferred since the latter can convert glucose to lactate, which R. eutropha can metabolize easily. Tohyama et al. [24] maximized PHB production in a well-mixed fed-batch bioreactor with glucose and (NH42SO4 as the primary substrates. Since production-scale bioreactors often deviate from ideal laboratory-scale reactors, a large bioreactor was simulated by means of a dispersion model with the kinetics determined by Tohyama et al. [24] and dispersion set at an optimum Peclet number of 20 [32]. The time-dependent feed rates of the two substrates were determined through a genetic algorithm (GA to maximize PHB production. This bioreactor produced 22.2% more PHB per liter and 12.8% more cell mass than achieved by Tohyama et al. [24]. These results, and similar observations with other fermentations, indicate the feasibility of enhancing the efficiency of large nonideal bioreactors through GA optimizations.

  10. Optimization of critical factors to enhance polyhydroxyalkanoates (PHA) synthesis by mixed culture using Taguchi design of experimental methodology.

    Science.gov (United States)

    Venkata Mohan, S; Venkateswar Reddy, M

    2013-01-01

    Optimizing different factors is crucial for enhancement of mixed culture bioplastics (polyhydroxyalkanoates (PHA)) production. Design of experimental (DOE) methodology using Taguchi orthogonal array (OA) was applied to evaluate the influence and specific function of eight important factors (iron, glucose concentration, VFA concentration, VFA composition, nitrogen concentration, phosphorous concentration, pH, and microenvironment) on the bioplastics production. Three levels of factor (2(1) × 3(7)) variation were considered with symbolic arrays of experimental matrix [L(18)-18 experimental trails]. All the factors were assigned with three levels except iron concentration (2(1)). Among all the factors, microenvironment influenced bioplastics production substantially (contributing 81%), followed by pH (11%) and glucose concentration (2.5%). Validation experiments were performed with the obtained optimum conditions which resulted in improved PHA production. Good substrate degradation (as COD) of 68% was registered during PHA production. Dehydrogenase and phosphatase enzymatic activities were monitored during process operation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Culture.

    Science.gov (United States)

    Smith, Timothy B; Rodríguez, Melanie Domenech; Bernal, Guillermo

    2011-02-01

    This article summarizes the definitions, means, and research of adapting psychotherapy to clients' cultural backgrounds. We begin by reviewing the prevailing definitions of cultural adaptation and providing a clinical example. We present an original meta-analysis of 65 experimental and quasi-experimental studies involving 8,620 participants. The omnibus effect size of d = .46 indicates that treatments specifically adapted for clients of color were moderately more effective with that clientele than traditional treatments. The most effective treatments tended to be those with greater numbers of cultural adaptations. Mental health services targeted to a specific cultural group were several times more effective than those provided to clients from a variety of cultural backgrounds. We recommend a series of research-supported therapeutic practices that account for clients' culture, with culture-specific treatments being more effective than generally culture-sensitive treatments. © 2010 Wiley Periodicals, Inc.

  12. Validating Culture and Gender-Specific Constructs: A Mixed-Method Approach to Advance Assessment Procedures in Cross-Cultural Settings

    Science.gov (United States)

    Hitchcock, John H.; Sarkar, Sreeroopa; Nastasi, Bonnie; Burkholder, Gary; Varjas, Kristen; Jayasena, Asoka

    2006-01-01

    Despite on-going calls for developing cultural competency among mental health practitioners, few assessment instruments consider cultural variation in psychological constructs. To meet the challenge of developing measures for minority and international students, it is necessary to account for the influence culture may have on the latent constructs…

  13. Transcriptomic and metabolic responses of Staphylococcus aureus in mixed culture with Lactobacillus plantarum, Streptococcus thermophilus and Enterococcus durans in milk.

    Science.gov (United States)

    Zdenkova, Kamila; Alibayov, Babek; Karamonova, Ludmila; Purkrtova, Sabina; Karpiskova, Renata; Demnerova, Katerina

    2016-09-01

    Staphylococcus aureus is a major food-borne pathogen due to the production of enterotoxin and is particularly prevalent in contaminated milk and dairy products. The lactic acid bacteria (LAB) are widely used as biocontrol agents in fermented foods which can inhibit pathogenic flora. In our work, we investigated the influence of three strains of LAB (Lactobacillus plantarum, Streptococcus thermophilus and Enterococcus durans) on the relative expression of three enterotoxin genes (sea, sec, sell) and eight virulence and/or regulatory genes (sarA, saeS, codY, srrA, rot, hld/RNAIII, agrA/RNAII, sigB) in two S. aureus strains (MW2 and Sa1612) in TSB and reduced-fat milk (1.5 %) at 30 °C over a 24-h period. The tested LAB and S. aureus strains proved to be mutually non-competitive or only slightly competitive during co-cultivation. In addition, under the above-mentioned conditions, differential gene expression between the S. aureus MW2 and Sa1612 strains was well documented. S. aureus growth was changed in mixed culture with LAB; however, its effect on the repression of sea and sec expression correlated with production of these virulence factors. In comparison, the presence of LAB strains generally inhibited the expression of sec, sell, sarA, seaS, agrA/RNAII and hld/RNAIII genes. The effect of LAB strains presence on the expression of sea, codY, srrA, rot and sigB genes was medium, time, LAB and S. aureus strain specific. SEA and SEC production was significantly reduced in milk compared to TSB in pure culture. After the 24-h cultivation, S. aureus MW2 and Sa1612 SEC production was 187 and 331 times lower in milk compared to TSB, respectively (0.07 and 0.39 ng/mL in milk, versus 13.1 and 129.2 ng/mL in TSB, respectively). At the same time S. aureus MW2 and Sa1612 SEA production was 77 and 68 times lower in milk compared to TSB, respectively (0.99 and 0.17 ng/mL in milk, versus 76.4 and 11.5 ng/mL in TSB, respectively). This study has revealed new insights into the

  14. Community proteomics provides functional insight into polyhydroxyalkanoate production by a mixed microbial culture cultivated on fermented dairy manure.

    Science.gov (United States)

    Hanson, Andrea J; Guho, Nicholas M; Paszczynski, Andrzej J; Coats, Erik R

    2016-09-01

    Polyhydroxyalkanoates (PHAs) are bio-based, biodegradable polyesters that can be produced from organic-rich waste streams using mixed microbial cultures (MMCs). To maximize PHA production, MMCs are enriched for bacteria with a high polymer storage capacity through the application of aerobic dynamic feeding (ADF) in a sequencing batch reactor (SBR), which consequently induces a feast-famine metabolic response. Though the feast-famine response is generally understood empirically at a macro-level, the molecular level is less refined. The objective of this study was to investigate the microbial community composition and proteome profile of an enriched MMC cultivated on fermented dairy manure. The enriched MMC exhibited a feast-famine response and was capable of producing up to 40 % (wt. basis) PHA in a fed-batch reactor. High-throughput 16S rRNA gene sequencing revealed a microbial community dominated by Meganema, a known PHA-producing genus not often observed in high abundance in enrichment SBRs. The application of the proteomic methods two-dimensional electrophoresis and LC-MS/MS revealed PHA synthesis, energy generation, and protein synthesis prominently occurring during the feast phase, corroborating bulk solution variable observations and theoretical expectations. During the famine phase, nutrient transport, acyl-CoA metabolism, additional energy generation, and housekeeping functions were more pronounced, informing previously under-determined MMC functionality under famine conditions. During fed-batch PHA production, acetyl-CoA acetyltransferase and PHA granule-bound phasin proteins were in increased abundance relative to the SBR, supporting the higher PHA content observed. Collectively, the results provide unique microbial community structural and functional insight into feast-famine PHA production from waste feedstocks using MMCs.

  15. Methylocapsa palsarum sp. nov., a methanotroph isolated from a subArctic discontinuous permafrost ecosystem.

    Science.gov (United States)

    Dedysh, Svetlana N; Didriksen, Alena; Danilova, Olga V; Belova, Svetlana E; Liebner, Susanne; Svenning, Mette M

    2015-10-01

    An aerobic methanotrophic bacterium was isolated from a collapsed palsa soil in northern Norway and designated strain NE2T. Cells of this strain were Gram-stain-negative, non-motile, non-pigmented, slightly curved thick rods that multiplied by normal cell division. The cells possessed a particulate methane monooxygenase enzyme (pMMO) and utilized methane and methanol. Strain NE2T grew in a wide pH range of 4.1–8.0 (optimum pH 5.2–6.5) at temperatures between 6 and 32 °C (optimum 18–25 °C), and was capable of atmospheric nitrogen fixation under reduced oxygen tension. The major cellular fatty acids were C18 : 1ω7c, C16 : 0 and C16 : 1ω7c, and the DNA G+C content was 61.7 mol%. The isolate belonged to the family Beijerinckiaceae of the class Alphaproteobacteria and was most closely related to the facultative methanotroph Methylocapsa aurea KYGT (98.3 % 16S rRNA gene sequence similarity and 84 % PmoA sequence identity). However, strain NE2T differed from Methylocapsa aurea KYGT by cell morphology, the absence of pigmentation, inability to grow on acetate, broader pH growth range, and higher tolerance to NaCl. Therefore, strain NE2T represents a novel species of the genus Methylocapsa, for which we propose the name Methylocapsa palsarum sp. nov. The type strain is NE2T ( = LMG 28715T = VKM B-2945T).

  16. Aerobic methanotrophic communities at the Red Sea brine-seawater interface

    Directory of Open Access Journals (Sweden)

    Rehab Z. Abdallah

    2014-09-01

    Full Text Available The central rift of the Red Sea contains 25 brine pools with different physicochemical conditions, dictating the diversity and abundance of the microbial community. Three of these pools, the Atlantis II, Kebrit and Discovery Deeps, are uniquely characterized by a high concentration of hydrocarbons. The brine-seawater interface, described as an anoxic-oxic (brine-seawater boundary, is characterized by a high methane concentration, thus favoring aerobic methane oxidation. The current study analyzed the aerobic free–living methane-oxidizing bacterial communities that potentially contribute to methane oxidation at the brine-seawater interfaces of the three aforementioned brine pools, using metagenomic pyrosequencing, 16S rRNA pyrotags and pmoA library constructs. The sequencing of 16S rRNA pyrotags revealed that these interfaces are characterized by high microbial community diversity. Signatures of aerobic methane-oxidizing bacteria were detected in the Atlantis II Interface (ATII-I and the Kebrit Deep Upper (KB-U and Lower (KB-L brine-seawater interfaces. Through phylogenetic analysis of pmoA, we further demonstrated that the ATII-I aerobic methanotroph community is highly diverse. We propose four ATII-I pmoA clusters. Most importantly, cluster 2 groups with marine methane seep methanotrophs, and cluster 4 represent a unique lineage of an uncultured bacterium with divergent alkane monooxygenases. Moreover, non-metric multidimensional scaling (NMDS based on the ordination of putative enzymes involved in methane metabolism showed that the Kebrit interface layers were distinct from the ATII-I and DD-I brine-seawater interfaces.

  17. Detection of putatively thermophilic anaerobic methanotrophs in diffuse hydrothermal vent fluids.

    Science.gov (United States)

    Merkel, Alexander Y; Huber, Julie A; Chernyh, Nikolay A; Bonch-Osmolovskaya, Elizaveta A; Lebedinsky, Alexander V

    2013-02-01

    The anaerobic oxidation of methane (AOM) is carried out by a globally distributed group of uncultivated Euryarchaeota, the anaerobic methanotrophic arachaea (ANME). In this work, we used G+C analysis of 16S rRNA genes to identify a putatively thermophilic ANME group and applied newly designed primers to study its distribution in low-temperature diffuse vent fluids from deep-sea hydrothermal vents. We found that the G+C content of the 16S rRNA genes (P(GC)) is significantly higher in the ANME-1GBa group than in other ANME groups. Based on the positive correlation between the P(GC) and optimal growth temperatures (T(opt)) of archaea, we hypothesize that the ANME-1GBa group is adapted to thrive at high temperatures. We designed specific 16S rRNA gene-targeted primers for the ANME-1 cluster to detect all phylogenetic groups within this cluster, including the deeply branching ANME-1GBa group. The primers were successfully tested both in silico and in experiments with sediment samples where ANME-1 phylotypes had previously been detected. The primers were further used to screen for the ANME-1 microorganisms in diffuse vent fluid samples from deep-sea hydrothermal vents in the Pacific Ocean, and sequences belonging to the ANME-1 cluster were detected in four individual vents. Phylotypes belonging to the ANME-1GBa group dominated in clone libraries from three of these vents. Our findings provide evidence of existence of a putatively extremely thermophilic group of methanotrophic archaea that occur in geographically and geologically distinct marine hydrothermal habitats.

  18. Differential detection of type II methanotrophic bacteria in acidic peatlands using newly developed 16S rRNA-targeted fluorescent oligonucleotide probes.

    Science.gov (United States)

    Dedysh, Svetlana N; Dunfield, Peter F; Derakshani, Manigee; Stubner, Stephan; Heyer, Jürgen; Liesack, Werner

    2003-04-01

    Abstract Based on an extensive 16S rRNA sequence database for type II methanotrophic bacteria, a set of 16S rRNA-targeted oligonucleotide probes was developed for differential detection of specific phylogenetic groups of these bacteria by fluorescence in situ hybridisation (FISH). This set of oligonucleotides included a genus-specific probe for Methylocystis (Mcyst-1432) and three species-specific probes for Methylosinus sporium (Msins-647), Methylosinus trichosporium (Msint-1268) and the recently described acidophilic methanotroph Methylocapsa acidiphila (Mcaps-1032). These novel probes were applied to further characterise the type II methanotroph community that was detected in an acidic Sphagnum peat from West Siberia in a previous study (Dedysh et al. (2001) Appl. Environ. Microbiol. 67, 4850-4857). The largest detectable population of indigenous methanotrophs simultaneously hybridised with a group-specific probe targeting all currently known Methylosinus/Methylocystis spp. (M-450), with a genus-specific probe for Methylocystis spp. (Mcyst-1432), and with an additional probe (Mcyst-1261) that had been designed to target a defined phylogenetic subgroup of Methylocystis spp. The same subgroup of Methylocystis was also detected in acidic peat sampled from Sphagnum-dominated wetland in northern Germany. The population size of this peat-inhabiting Methylocystis subgroup was 2.0+/-0.1x10(6) cells g(-1) (wet weight) of peat from Siberia and 5.5+/-0.5x10(6) cells g(-1) of peat from northern Germany. This represented 60 and 95%, respectively, of the total number of methanotroph cells detected by FISH in these two wetland sites. Other major methanotroph populations were M. acidiphila and Methylocella palustris. Type I methanotrophs accounted for not more than 1% of total methanotroph cells. Neither M. trichosporium nor M. sporium were detected in acidic Sphagnum peat.

  19. Optimized cryopreservation of mixed microbial communities for conserved functionality and diversity.

    Directory of Open Access Journals (Sweden)

    Frederiek-Maarten Kerckhof

    Full Text Available The use of mixed microbial communities (microbiomes for biotechnological applications has steadily increased over the past decades. However, these microbiomes are not readily available from public culture collections, hampering their potential for widespread use. The main reason for this lack of availability is the lack of an effective cryopreservation protocol. Due to this critical need, we evaluated the functionality as well as the community structure of three different types of microbiomes before and after cryopreservation with two cryoprotective agents (CPA. Microbiomes were selected based upon relevance towards applications: (1 a methanotrophic co-culture (MOB, with potential for mitigation of greenhouse gas emissions, environmental pollutants removal and bioplastics production; (2 an oxygen limited autotrophic nitrification/denitrification (OLAND biofilm, with enhanced economic and ecological benefits for wastewater treatment, and (3 fecal material from a human donor, with potential applications for fecal transplants and pre/probiotics research. After three months of cryopreservation at -80 °C, we found that metabolic activity, in terms of the specific activity recovery of MOB, aerobic ammonium oxidizing bacteria (AerAOB and anaerobic AOB (AnAOB, anammox in the OLAND mixed culture, resumes sooner when one of our selected CPA [dimethyl sulfoxide (DMSO and DMSO plus trehalose and tryptic soy broth (DMSO+TT] was added. However, the activity of the fecal community was not influenced by the CPA addition, although the preservation of the community structure (as determined by 16S rRNA gene sequencing was enhanced by addition of CPA. In summary, we have evaluated a cryopreservation protocol that succeeded in preserving both community structure and functionality of value-added microbiomes. This will allow individual laboratories and culture collections to boost the use of microbiomes in biotechnological applications.

  20. Biopolymer Production Kinetics of Mixed Culture Using Wastewater Sludge as a Raw Material and the Effect of Different Cations on Biopolymer Applications in Water and Wastewater Treatment.

    Science.gov (United States)

    More, T T; Yan, S; Tyagi, R D; Surampalli, R Y

    2016-05-01

    Thirteen extracellular polymeric substances (EPS) producing bacterial strains were cultivated (as mixed culture) in the sterilized sludge (suspended solids of 25 g/L) and the batch fermentation was carried out. Mixed culture revealed a high specific growth rate of 0.35/hr. The EPS production rate was higher up to 24 hours, which gradually decreased with further incubation. The kinetic estimates demonstrated growth-associated EPS production. Broth EPS revealed higher flocculation activity when combined with different cations (Ca(2+), Mg(2+), Fe(3+), and Al(3+)) in river water (≥90%), municipal wastewater (≥90%), and brewery wastewater (≥80%), respectively. A low dose (5 to 40 mg/L) of trivalent cations was required to achieve higher flocculation compared to the divalent cations (50 to 250 mg/L). Flocculation performance of EPS was comparable to Magnafloc-155 (chemical polymer) and, hence, it could be used as a flocculant.

  1. Deficits in knowledge, attitude, and practice towards blood culture sampling: results of a nationwide mixed-methods study among inpatient care physicians in Germany.

    Science.gov (United States)

    Raupach-Rosin, Heike; Duddeck, Arne; Gehrlich, Maike; Helmke, Charlotte; Huebner, Johannes; Pletz, Mathias W; Mikolajczyk, Rafael; Karch, André

    2017-08-01

    Blood culture (BC) sampling rates in Germany are considerably lower than recommended. Aim of our study was to assess knowledge, attitudes, and practice of physicians in Germany regarding BC diagnostics. We conducted a cross-sectional mixed-methods study among physicians working in inpatient care in Germany. Based on the results of qualitative focus groups, a questionnaire-based quantitative study was conducted in 2015-2016. In total, 706 medical doctors and final-year medical students from 11 out of 16 federal states in Germany participated. BC sampling was considered an important diagnostic tool by 95% of the participants. However, only 23% of them would collect BCs in three scenarios for which BC ordering is recommended by present guidelines in Germany; almost one out of ten physicians would not have taken blood cultures in any of the three scenarios. The majority of participants (74%) reported not to adhere to the guideline recommendation that blood culture sampling should include at least two blood culture sets from two different injection sites. High routine in blood culture sampling, perceived importance of blood culture diagnostics, the availability of an in-house microbiological lab, and the department the physician worked in were identified as predictors for good blood culture practice. Our study suggests that there are substantial deficits in BC ordering and the application of guidelines for good BC practice in Germany. Based on these findings, multimodal interventions appear necessary for improving BC diagnostics.

  2. Final Technical Report: Role of Methanotrophs in Metal Mobilization, Metal Immobilization and Mineral Weathering: Effects on the In Situ Microbial Community and the Sustainability of Subsurface Water Systems

    Energy Technology Data Exchange (ETDEWEB)

    Semrau, Jeremy D. [Univ. of Michigan, Ann Arbor, MI (United States); DiSpirito, Alan A. [Iowa State Univ., Ames, IA (United States)

    2016-11-06

    Activities from this DOE sponsored project can be divided into four broad areas: (1) investigations into the potential of methanobactin, a biogenic metal-binding agent produced by methanotrophs, in mitigating mercury toxicity; (2) elucidation of the genetic basis for methanobactin synthesis from methanotrophs; (3) examination of differential gene expression of M. trichosporium OB3b when grown in the presence of varying amounts of copper and/or cerium, and (4) collection and characterization of soil cores from Savannah River Test Site to determine the ubiquity of methanobactin producing methanotrophs. From these efforts, we have conclusively shown that methanobactin can strongly bind mercury as Hg[II], and in so doing significantly reduce the toxicity of this metal to microbes. Further, we have deduced the genetic basis of methanobactin production in methanotrophs, enabling us to construct mutants such that we can now ascribe function to different genes as well as propose a pathway for methanobactin biosynthesis. We have also clear evidence that copper and cerium (as an example of a rare earth element) dramatically affect gene expression in methanotrophs, and thus have an important impact on the activity and application of these microbes to a variety of environmental and industrial issues. Finally, we successfully isolated one methanotroph from the deep subsurface of the Savannah River Test Site and characterized the ability of different forms of methanobactin to mobilize copper and mercury from these soils.

  3. Complete genome sequence of the extremely acidophilic methanotroph isolate V4, Methylacidiphilum infernorum, a representative of the bacterial phylum Verrucomicrobia

    Directory of Open Access Journals (Sweden)

    Stott Matthew B

    2008-07-01

    Full Text Available Abstract Background The phylum Verrucomicrobia is a widespread but poorly characterized bacterial clade. Although cultivation-independent approaches detect representatives of this phylum in a wide range of environments, including soils, seawater, hot springs and human gastrointestinal tract, only few have been isolated in pure culture. We have recently reported cultivation and initial characterization of an extremely acidophilic methanotrophic member of the Verrucomicrobia, strain V4, isolated from the Hell's Gate geothermal area in New Zealand. Similar organisms were independently isolated from geothermal systems in Italy and Russia. Results We report the complete genome sequence of strain V4, the first one from a representative of the Verrucomicrobia. Isolate V4, initially named "Methylokorus infernorum" (and recently renamed Methylacidiphilum infernorum is an autotrophic bacterium with a streamlined genome of ~2.3 Mbp that encodes simple signal transduction pathways and has a limited potential for regulation of gene expression. Central metabolism of M. infernorum was reconstructed almost completely and revealed highly interconnected pathways of autotrophic central metabolism and modifications of C1-utilization pathways compared to other known methylotrophs. The M. infernorum genome does not encode tubulin, which was previously discovered in bacteria of the genus Prosthecobacter, or close homologs of any other signature eukaryotic proteins. Phylogenetic analysis of ribosomal proteins and RNA polymerase subunits unequivocally supports grouping Planctomycetes, Verrucomicrobia and Chlamydiae into a single clade, the PVC superphylum, despite dramatically different gene content in members of these three groups. Comparative-genomic analysis suggests that evolution of the M. infernorum lineage involved extensive horizontal gene exchange with a variety of bacteria. The genome of M. infernorum shows apparent adaptations for existence under extremely

  4. Evaluation of the Synergistic Effect of Mixed Cultures of White-Rot Fungus Pleurotus ostreatus and Biosurfactant-Producing Bacteria on DDT Biodegradation.

    Science.gov (United States)

    Purnomo, Adi Setyo; Ashari, Khoirul; Hermansyah, Farizha Triyogi

    2017-07-28

    DDT (1,1,1-trichloro-2,2- bis (4-chlorophenyl) ethane) is one of the organic synthetic pesticides that has many negative effects for human health and the environment. The purpose of this study was to investigate the synergistic effect of mixed cutures of white-rot fungus, Pleurotus ostreatus , and biosurfactant-producing bacteria, Pseudomonas aeruginosa and Bacillus subtilis , on DDT biodegradation. Bacteria were added into the P. ostreatus culture (mycelial wet weight on average by 8.53 g) in concentrations of 1, 3, 5, and 10 ml (1 ml ≈ 1.25 × 10 9 bacteria cells/ml culture). DDT was degraded to approximately 19% by P. ostreatus during the 7-day incubation period. The principal result of this study was that the addition of 3 ml of P. aeruginosa into P. ostreatus culture gave the highest DDT degradation rate (approximately 86%) during the 7-day incubation period. This mixed culture combination of the fungus and bacteria also gave the best ratio of optimization of 1.91. DDD (1,1-dichloro-2,2- bis (4-chlorophenyl) ethane), DDE (1,1-dichloro-2,2- bis (4-chlorophenyl) ethylene), and DDMU (1-chloro-2,2- bis (4-chlorophenyl) ethylene) were detected as metabolic products from the DDT degradation by P. ostreatus and P. aeruginosa . The results of this study indicate that P. aeruginosa has a synergistic relationship with P. ostreatus and can be used to optimize the degradation of DDT by P. ostreatus .

  5. Hydrodynamic characteristics and mixing behaviour of Sclerotium glucanicum culture fluids in an airlift reactor with an internal loop used for scleroglucan production.

    Science.gov (United States)

    Kang, X; Wang, H; Wang, Y; Harvey, L M; McNeil, B

    2001-10-01

    The filamentous fungus, Sclerotium glucanicum NRRL 3006, was cultivated in a 0.008 m(3) airlift bioreactor with internal recirculation loop (ARL-IL) for production of the biopolymer, scleroglucan. The rheological behaviour of the culture fluid was characterised by measurement of the fluid consistency coefficient (K) and the flow behaviour index (n). Based on these measurements, the culture fluid changed from a low viscosity Newtonian system early in the process, to a viscous non-Newtonian (pseudoplastic) system. In addition, reactor hydrodynamics and mixing behaviour were characterised by measurement of whole mean gas hold-up (epsilon(g)), liquid re-circulation velocity (U(ld)) and mixing time (t(m)). Under identical process conditions, the effects of the viscosity of the culture fluid and air flow rate on epsilon(g), U(ld) and t(m) were examined and empirical correlations for epsilon(g), U(ld) and t(m) with both superficial velocity U(g) and consistency coefficient K were obtained and expressed separately. The correlations obtained are likely to describe the behaviour of real fungal culture fluids more accurately than previous correlations based on Newtonian or simulated non-Newtonian systems.

  6. Enrichment of anaerobic nitrate-dependent methanotrophic ?Candidatus Methanoperedens nitroreducens? archaea from an Italian paddy field soil

    OpenAIRE

    Vaksmaa, Annika; Guerrero-Cruz, Simon; van Alen, Theo A.; Cremers, Geert; Ettwig, Katharina F.; L?ke, Claudia; Jetten, Mike S. M.

    2017-01-01

    Paddy fields are a significant source of methane and contribute up to 20% of total methane emissions from wetland ecosystems. These inundated, anoxic soils featuring abundant nitrogen compounds and methane are an ideal niche for nitrate-dependent anaerobic methanotrophs. After 2?years of enrichment with a continuous supply of methane and nitrate as the sole electron donor and acceptor, a stable enrichment dominated by ?Candidatus Methanoperedens nitroreducens? archaea and ?Candidatus Methylom...

  7. Biological synthesis of very small silver nanoparticles by culture supernatant of Klebsiella pneumonia: The effects of visible-light irradiation and the liquid mixing process

    International Nuclear Information System (INIS)

    Mokhtari, Narges; Daneshpajouh, Shahram; Seyedbagheri, Seyedali; Atashdehghan, Reza; Abdi, Khosro; Sarkar, Saeed; Minaian, Sara; Shahverdi, Hamid Reza; Shahverdi, Ahmad Reza

    2009-01-01

    This study has investigated different visible-light irradiation's effect on the formation of silver nanoparticles from silver nitrate using the culture supernatant of Klebsiella pneumonia. Our study shows that visible-light emission can significantly prompt the synthesis of silver nanoparticles. Also, the study experimentally investigated the liquid mixing process effect on silver nanoparticle synthesis by visible-light irradiation. This study successfully synthesized uniformly dispersed silver nanoparticles with a uniform size and shape in the range of 1-6 nm with an average size of 3 nm. Furthermore, the study investigated the mechanism of the reduction of silver ions by culture supernatant of K. pneumonia, and used X-ray diffraction to characterize silver chloride as an intermediate compound. Silver chloride was prepared synthetically and used as a substrate for the synthesis of silver nanoparticles by culture supernatant of K. pneumonia. The silver nanoparticles have been prepared from silver chloride during this investigation for the first time.

  8. Biological synthesis of very small silver nanoparticles by culture supernatant of Klebsiella pneumonia: The effects of visible-light irradiation and the liquid mixing process

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtari, Narges [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Daneshpajouh, Shahram; Seyedbagheri, Seyedali; Atashdehghan, Reza [Hydrometallurgy Research Unit, Research and Development Center, National Iranian Copper Industries Company, Sarcheshmeh, Rafsanjan (Iran, Islamic Republic of); Abdi, Khosro [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sarkar, Saeed [Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Minaian, Sara [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Shahverdi, Hamid Reza [Department of Material Science, Faculty of Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Shahverdi, Ahmad Reza, E-mail: shahverd@sina.tums.ac.ir [Department of Pharmaceutical Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2009-06-03

    This study has investigated different visible-light irradiation's effect on the formation of silver nanoparticles from silver nitrate using the culture supernatant of Klebsiella pneumonia. Our study shows that visible-light emission can significantly prompt the synthesis of silver nanoparticles. Also, the study experimentally investigated the liquid mixing process effect on silver nanoparticle synthesis by visible-light irradiation. This study successfully synthesized uniformly dispersed silver nanoparticles with a uniform size and shape in the range of 1-6 nm with an average size of 3 nm. Furthermore, the study investigated the mechanism of the reduction of silver ions by culture supernatant of K. pneumonia, and used X-ray diffraction to characterize silver chloride as an intermediate compound. Silver chloride was prepared synthetically and used as a substrate for the synthesis of silver nanoparticles by culture supernatant of K. pneumonia. The silver nanoparticles have been prepared from silver chloride during this investigation for the first time.

  9. FIBER QUALITIES OF PRETREATED BETUNG BAMBOO (Dendrocalamusasper BY MIXED CULTURE OF WHITE-ROT FUNGI WITH RESPECT TO ITS USE FOR PULP/PAPER

    Directory of Open Access Journals (Sweden)

    Widya Fatriasari

    2013-10-01

    Full Text Available Previous research on anatomical structures of pretreated large (betung bamboo (Dendrocalamusasper using single culture of white-rot fungi has been investigated, which revealed that the pretreatment caused the decrease in the Runkel ratioas well as the coefficient rigidity and the increase in the flexibility ratio of their corresponding bamboo fibers. However, there is no study reported on the anatomical structure changes of them caused by pretreatment using mixed culture of white-rot fungi. This paper reports the results of the research on paper/pulp quality after different treatments. Pretreatment that used Trametes versicolor fungi and lasted for 45 days inflicted intensive fiber damages compared with those of untreated bamboo (control. Fresh and barkless large (betung bamboo chips of 2 year's old, and 1.6 cm in length, were inoculated by 10% of mixed culture of white-rot fungi inoculums stock for 30 and 45 days in room temperature. There were four treatment groups of mixed culture, i.e T. versi color and P. ostreatus (TVPO; P. ostreatus and P. chrysosporium (POPC; P. chrysosporium and T.versi color (PCTV; and P.chrysosporium,  T.versicolorand  P.ostreatus  (TVPCPO.After  the  inoculation  period,  the  chips  weremacerated into separate fibers using Scultze method to analyze the fiber dimension and its derived values. The fibers were then observed regarding their macro and microscopic structures by optical microscope. Mixed culture pretreatment of white-rot fungi accelerated improvement of fiber morphology and fiber derived value characteristics, except for Muhlsteph ratio. The fiber derived values oftreated bamboo tended to improve compared to those of untreated bamboo, there by requiring milder pulping conditions. Accordingly, the treated bamboo would indicatively produce a good quality pulp (grade I based on FAO and LPHH (Forest Product Research Report requirements. Co-culture treatment using P. chrysosporium and P. ostreatus for

  10. Development and testing of the ‘Culture of Care Barometer’ (CoCB) in healthcare organisations: a mixed methods study

    Science.gov (United States)

    Rafferty, Anne Marie; Philippou, Julia; Fitzpatrick, Joanne M; Pike, Geoff; Ball, Jane

    2017-01-01

    Objective Concerns about care quality have prompted calls to create workplace cultures conducive to high-quality, safe and compassionate care and to provide a supportive environment in which staff can operate effectively. How healthcare organisations assess their culture of care is an important first step in creating such cultures. This article reports on the development and validation of a tool, the Culture of Care Barometer, designed to assess perceptions of a caring culture among healthcare workers preliminary to culture change. Design/setting/participants An exploratory mixed methods study designed to develop and test the validity of a tool to measure ‘culture of care’ through focus groups and questionnaires. Questionnaire development was facilitated through: a literature review, experts generating items of interest and focus group discussions with healthcare staff across specialities, roles and seniority within three types of public healthcare organisations in the UK. The tool was designed to be multiprofessional and pilot tested with a sample of 467 nurses and healthcare support workers in acute care and then validated with a sample of 1698 staff working across acute, mental health and community services in England. Exploratory factor analysis was used to identify dimensions underlying the Barometer. Results Psychometric testing resulted in the development of a 30-item questionnaire linked to four domains with retained items loading to four factors: organisational values (α=0.93, valid n=1568, M=3.7), team support (α=0.93, valid n=1557, M=3.2), relationships with colleagues (α=0.84, valid n=1617, M=4.0) and job constraints (α=0.70, valid n=1616, M=3.3). Conclusions The study developed a valid and reliable instrument with which to gauge the different attributes of care culture perceived by healthcare staff with potential for organisational benchmarking. PMID:28821526

  11. Influencing organisational culture to improve hospital performance in care of patients with acute myocardial infarction: a mixed-methods intervention study.

    Science.gov (United States)

    Curry, Leslie A; Brault, Marie A; Linnander, Erika L; McNatt, Zahirah; Brewster, Amanda L; Cherlin, Emily; Flieger, Signe Peterson; Ting, Henry H; Bradley, Elizabeth H

    2018-03-01

    Hospital organisational culture affects patient outcomes including mortality rates for patients with acute myocardial infarction; however, little is known about whether and how culture can be positively influenced. This is a 2-year, mixed-methods interventional study in 10 US hospitals to foster improvements in five domains of organisational culture: (1) learning environment, (2) senior management support, (3) psychological safety, (4) commitment to the organisation and (5) time for improvement. Outcomes were change in culture, uptake of five strategies associated with lower risk-standardised mortality rates (RSMR) and RSMR. Measures included a validated survey at baseline and at 12 and 24 months (n=223; average response rate 88%); in-depth interviews (n=393 interviews with 197 staff); and RSMR data from the Centers for Medicare and Medicaid Services. We observed significant changes (porganisational culture that supports high performance may help hospitals in their efforts to improve clinical outcomes. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  12. Evaluating a culturally tailored peer-mentoring and education pilot intervention among Chinese breast cancer survivors using a mixed-methods approach.

    Science.gov (United States)

    Lu, Qian; You, Jin; Man, Jenny; Loh, Alice; Young, Lucy

    2014-11-01

    To evaluate a social support intervention that was culturally tailored for Chinese Americans who face many challenges because of cultural and linguistic barriers. Intervention with a one-group pre- or post-test design, mixed methods, and a community-based participatory research (CBPR) approach. Southern California. 14 Chinese American breast cancer survivors post-treatment and eight breast cancer peer mentors. The intervention was a 10-week program to provide emotional and informational support through peer mentoring and education. Health outcomes were assessed before and after the intervention. Eight weekly process evaluations and two focus group interviews also were conducted. Depressive and anxiety symptoms. The program was associated with a decrease in depressive symptoms. Participants valued the program highly. Inductive analysis suggested possible mechanisms for effectiveness, such as reducing stigma, empowerment, and increased sense of belonging. The peer-mentoring and education program has the potential to serve as a model intervention for ethnic minorities. Mixed methods and CBPR are valuable in evaluating pilot interventions with minorities. Focusing on relationships may be fruitful for designing novel interventions for cancer survivors from collectivistic cultures. Peer-mentoring and education programs can be integrated into communities and clinics to improve care for underserved minority cancer survivors and to reduce health disparities.

  13. Oxygen availability and strain combination modulate yeast growth dynamics in mixed culture fermentations of grape must with Starmerella bacillaris and Saccharomyces cerevisiae.

    Science.gov (United States)

    Englezos, Vasileios; Cravero, Francesco; Torchio, Fabrizio; Rantsiou, Kalliopi; Ortiz-Julien, Anne; Lambri, Milena; Gerbi, Vincenzo; Rolle, Luca; Cocolin, Luca

    2018-02-01

    Starmerella bacillaris (synonym Candida zemplinina) is a non-Saccharomyces yeast that has been proposed as a co-inoculant of selected Saccharomyces cerevisiae strains in mixed culture fermentations to enhance the analytical composition of the wines. In order to acquire further knowledge on the metabolic interactions between these two species, in this study we investigated the impact of oxygen addition and combination of Starm. bacillaris with S. cerevisiae strains on the microbial growth and metabolite production. Fermentations were carried out under two different conditions of oxygen availability. Oxygen availability and strain combination clearly influenced the population dynamics throughout the fermentation. Oxygen concentration increased the survival time of Starm. bacillaris and decreased the growth rate of S. cerevisiae strains in mixed culture fermentations, whereas it did not affect the growth of the latter in pure culture fermentations. This study reveals new knowledge about the influence of oxygen availability on the successional evolution of yeast species during wine fermentation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Production of Nitrous Oxide from Nitrite in Stable Type II Methanotrophic Enrichments.

    Science.gov (United States)

    Myung, Jaewook; Wang, Zhiyue; Yuan, Tong; Zhang, Ping; Van Nostrand, Joy D; Zhou, Jizhong; Criddle, Craig S

    2015-09-15

    The coupled aerobic-anoxic nitrous decomposition operation is a new process for wastewater treatment that removes nitrogen from wastewater and recovers energy from the nitrogen in three steps: (1) NH4(+) oxidation to NO2(-), (2) NO2(-) reduction to N2O, and (3) N2O conversion to N2 with energy production. Here, we demonstrate that type II methanotrophic enrichments can mediate step two by coupling oxidation of poly(3-hydroxybutyrate) (P3HB) to NO2(-) reduction. Enrichments grown with NH4(+) and NO2(-) were subject to alternating 48-h aerobic and anoxic periods, in which CH4 and NO2(-) were added together in a "coupled" mode of operation or separately in a "decoupled mode". Community structure was stable in both modes and dominated by Methylocystis. In the coupled mode, production of P3HB and N2O was low. In the decoupled mode, significant P3HB was produced, and oxidation of P3HB drove reduction of NO2(-) to N2O with ∼ 70% conversion for >30 cycles (120 d). In batch tests of wasted cells from the decoupled mode, N2O production rates increased at low O2 or high NO2(-) levels. The results are significant for the development of engineered processes that remove nitrogen from wastewater and for understanding of conditions that favor environmental production of N2O.

  15. Development of a system for genetic manipulation of the facultative methanotroph Methylocella silvestris BL2.

    Science.gov (United States)

    Crombie, Andrew; Murrell, J Colin

    2011-01-01

    An understanding of the metabolism and metabolic regulation of the facultative methanotroph Methylocella silvestris BL2 is required to understand its role in methane oxidation in the environment, and methods for genetics manipulation are essential tools in these investigations. In addition, the ability to engineer the metabolic capabilities of M. silvestris may well have useful biotechnological applications. We describe a simple and effective method of genetic manipulation for this organism which relies on the electroporation of a linear DNA fragment to introduce chromosomal gene deletions. In a two-step procedure, the gene of interest is first replaced with an antibiotic-resistance cassette which is subsequently removed, resulting in an unmarked gene deletion. This method is illustrated by the deletion of isocitrate lyase, which abolished growth on one-carbon and severely disabled growth on two-carbon compounds. Subsequent complementation with the wild-type gene and promoter restored growth, demonstrating stable transcription from the broad-host-range plasmid employed. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Methylocella tundrae sp. nov., a novel methanotrophic bacterium from acidic tundra peatlands.

    Science.gov (United States)

    Dedysh, Svetlana N; Berestovskaya, Yulia Y; Vasylieva, Lina V; Belova, Svetlana E; Khmelenina, Valentina N; Suzina, Natalia E; Trotsenko, Yuri A; Liesack, Werner; Zavarzin, George A

    2004-01-01

    A novel species, Methylocella tundrae, is proposed for three methanotrophic strains (T4T, TCh1 and TY1) isolated from acidic Sphagnum tundra peatlands. These strains are aerobic, Gram-negative, non-motile, dinitrogen-fixing rods that possess a soluble methane monooxygenase and utilize the serine pathway for carbon assimilation. Strains T4T, TCh1 and TY1 are moderately acidophilic organisms capable of growth between pH 4.2 and 7.5 (optimum 5.5-6.0) and between 5 and 30 degrees C (optimum 15 degrees C). The major phospholipid fatty acid is 18:1omega7c. The DNA G+C content of strain T4T is 63.3 mol%. The three strains possess almost identical 16S rRNA gene sequences and are most closely related to two previously identified species of Methylocella, Methylocella palustris (97% similarity) and Methylocella silvestris (97.5% similarity). DNA-DNA hybridization values of strain T4T with Methylocella palustris KT and Methylocella silvestris BL2T were respectively 27 and 36%. Thus, the tundra strains represent a novel species, for which the name Methylocella tundrae sp. nov. is proposed. Strain T4T (=DSM 15673T=NCIMB 13949T) is the type strain.

  17. Solubility of methane in water and in a medium for the cultivation of methanotrophs bacteria

    International Nuclear Information System (INIS)

    Serra, Maria Celeste C.; Pessoa, F.L.P.; Palavra, A.M.F.

    2006-01-01

    Solubility of methane in water and in an aqueous growth medium for the cultivation of methanotrophs bacteria was determined over the temperature range 293.15 to 323.15 K and at atmospheric pressure. The measurements were carried out in a Ben-Naim/Baer type apparatus with a precision of about ±0.3%. The experimental results were determined using accurate thermodynamic relations. The mole fractions of the dissolved gas at the gas partial pressure of 101.325 kPa, the Henry coefficients at the water vapour pressure and the Ostwald coefficients at infinite dilution were obtained. A comparison between the solubility of methane in water and those observed in fermentation medium over the temperature range of 298.15 to 308.15 K has shown that this gas is about ±2.3% more soluble in water. The temperature dependence of the mole fractions of methane was also determined using the Clarke-Glew-Weiss equation and the thermodynamic quantities, Gibbs energy, enthalpy and entropy changes, associated with the dissolution process were calculated. Furthermore, the experimental Henry coefficients for methane in water are compared with those calculated by the scaled particle theory. The estimated Henry coefficients are about ±4% lower than the experimental ones

  18. A Low Ethanol Dose Affects all Types of Cells in Mixed Long-Term Embryonic Cultures of the Cerebellum

    DEFF Research Database (Denmark)

    Pickering, Chris; Wicher, Grzegorz; Rosendahl, Sofi

    2010-01-01

    of this ethanol dose, cultures were exposed for 30 days. After this period, virtually no neurons or myelinating oligodendrocytes were present in the ethanol-treated cultures. In conclusion, chronic exposure to ethanol, even at small doses, dramatically and persistently affects normal development........ We exposed a primary culture of rat cerebellum from embryonic day 17 (corresponding to second trimester in humans) to ethanol at a concentration of 17.6 mM which is roughly equivalent to one glass of wine. Acutely, there was no change in cell viability after 5 or 8 days of exposure relative...... to control. By 11 days, a reduction in the number of viable cells was observed without an accompanying change in caspase-3 activity (marker of apoptotic cell death), suggesting changes in cell proliferation. As the proportion of nestin-positive cells was higher in the ethanol-treated cultures after 5 days...

  19. Doenjang prepared with mixed starter cultures attenuates azoxymethane and dextran sulfate sodium-induced colitis-associated colon carcinogenesis in mice

    Directory of Open Access Journals (Sweden)

    Ji-Kang Jeong

    2014-01-01

    Full Text Available Backgrounds: Doenjang is traditional Korean fermented soybean paste and widely known for its various health benefits including anticancer effect. In this study, we manufactured doenjang with the grain-type meju using probiotic mixed starter cultures of Aspegillus oryzae, Bacillus subtilis-SKm, and Lactococcus lactis-GAm to improve the qualities and beneficial properties of doenjang. Materials and Methods: The inhibitory effects of the doenjang prepared with the grain-type meju using mixed starter cultures were investigated in azoxymethane (AOM and dextran sulfate sodium (DSS-induced colon carcinogenesis mice model. AOM and DSS colon carcinogenesis was induced in female C57BL/6 mice, and doenjang was orally administered for 4 weeks. Body weight, colon length, and colon weight of mice were determined, and colonic tissues were histologically evaluated. The serum levels of proinflammatory cytokines as well as the expression of inflammation- and apoptosis-related genes in colonic tissue were also analyzed. Results: Administration of the doenjang using probiotic mixed starter cultures ameliorated the symptoms of colon cancer, and reduced the incidence of neoplasia, and reduced the levels of serum proinflammatory cytokines such as interleukin-6, and tumor necrosis factor-α and inducible nitric oxide synthase and cycloooxygenase-2 expression levels in colonic tissue. In addition, it increased Bax and reduced Bcl-2 expression levels and increased p21 and p53 expression in the colonic tissues. Conclusion: These findings indicate that the doenjang attenuated colon carcinogenesis induced by AOM and DSS by ameliorating the symptoms of colon cancer, reducing the occurrence of neoplasia, regulating proinflammatory cytokine levels, and controlling the expressions of inflammation- and apoptosis-related genes in the colonic tissue.

  20. Identification of active methanotrophs in a landfill cover soil through detection of expression of 16S rRNA and functional genes.

    Science.gov (United States)

    Chen, Yin; Dumont, Marc G; Cébron, Aurélie; Murrell, J Colin

    2007-11-01

    Active methanotrophs in a landfill soil were revealed by detecting the 16S rRNA of methanotrophs and the mRNA transcripts of key genes involved in methane oxidation. New 16S rRNA primers targeting type I and type II methanotrophs were designed and optimized for analysis by denaturing gradient gel electrophoresis. Direct extraction of RNA from soil enabled the analysis of the expression of the functional genes: mmoX, pmoA and mxaF, which encode subunits of soluble methane monooxygenase, particulate methane monooxygenase and methanol dehydrogenase respectively. The 16S rRNA polymerase chain reaction (PCR) primers for type I methanotrophs detected Methylomonas, Methylosarcina and Methylobacter sequences from both soil DNA and cDNA which was generated from RNA extracted directly from the landfill cover soil. The 16S rRNA primers for type II methanotrophs detected primarily Methylocella and some Methylocystis 16S rRNA genes. Phylogenetic analysis of mRNA recovered from the soil indicated that Methylobacter, Methylosarcina, Methylomonas, Methylocystis and Methylocella were actively expressing genes involved in methane and methanol oxidation. Transcripts of pmoA but not mmoX were readily detected by reverse transcription polymerase chain reaction (RT-PCR), indicating that particulate methane monooxygenase may be largely responsible for methane oxidation in situ.

  1. Monophyletic group of unclassified γ-Proteobacteria dominates in mixed culture biofilm of high-performing oxygen reducing biocathode

    NARCIS (Netherlands)

    Rothballer, Michael; Picot, Matthieu; Sieper, Tina; Arends, Jan B.A.; Schmid, Michael; Hartmann, Anton; Boon, Nico; Buisman, Cees J.N.; Barrière, Frédéric; Strik, David P.B.T.B.

    2015-01-01

    Several mixed microbial communities have been reported to show robust bioelectrocatalysis of oxygen reduction over time at applicable operation conditions. However, clarification of electron transfer mechanism(s) and identification of essential micro-organisms have not been realised. Therefore,

  2. The interaction effect of mixing starter cultures on homemade natural yogurt’s pH and viscosity

    Directory of Open Access Journals (Sweden)

    Hadi A. Dahlan

    2017-10-01

    Full Text Available Dairy yogurts are common food products consumed by people all over the world. Due to the simple process, many people have made their own natural yogurt at home. The fermentation due to the starter culture causes the textural properties of dairy yogurt. However, the literature is surprisingly scarce on the topic of starter culture interactions in the development of textural properties of dairy yogurt. This study investigated the interaction effect of three common starter cultures, Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophiles, on the viscosity of homemade yogurt. Using Design Expert software, a 10-run mixture model experiment was designed to examine the textural properties developed by single or multiple inoculation of these starter cultures. All yogurt formulations reached the isoelectric point of milk and had pHs in the range 3.97 to 4.32. Yogurt formulations with L. acidophilus and S. thermophilus resulted in viscosities which were similar to commercial yogurt viscosity (1.77 Pa.s, while L. bulgaricus resulted in yogurt with a lower viscosity. Based on the mixture model, L. acidophilus had most influence on the yogurt viscosity, followed by S. thermophilus and L. bulgaricus. In conclusion, L. acidophilus can be used as a single starter culture or combined with other starter cultures to develop high viscosity homemade yogurt. A Combination of S. thermophilus and L. acidphilus can also be used to develop high viscosity yogurts. However, L. bulgaricus should not be inoculated alone or become a dominant ratio in multiple starter culture inoculation as it will decrease the overall homemade yogurt viscosity.

  3. cultural

    Directory of Open Access Journals (Sweden)

    Irene Kreutz

    2006-01-01

    Full Text Available Es un estudio cualitativo que adoptó como referencial teorico-motodológico la antropología y la etnografía. Presenta las experiencias vivenciadas por mujeres de una comunidad en el proceso salud-enfermedad, con el objetivo de comprender los determinantes sócio-culturales e históricos de las prácticas de prevención y tratamiento adoptados por el grupo cultural por medio de la entrevista semi-estructurada. Los temas que emergieron fueron: la relación entre la alimentación y lo proceso salud-enfermedad, las relaciones con el sistema de salud oficial y el proceso salud-enfermedad y lo sobrenatural. Los dados revelaron que los moradores de la comunidad investigada tienen un modo particular de explicar sus procedimientos terapéuticos. Consideramos que es papel de los profesionales de la salud en sus prácticas, la adopción de abordajes o enfoques que consideren al individuo en su dimensión sócio-cultural e histórica, considerando la enorme diversidad cultural en nuestro país.

  4. Grooming and cultural socialization: a mixed method study of caregiving practices in Burma (Myanmar) and the United States.

    Science.gov (United States)

    Thein-Lemelson, Seinenu M

    2015-02-01

    Grooming behaviours are thought to be a crucial aspect of parenting and integral to the sociality of non-human mammals, but there have been few empirical studies on how grooming might be relevant to parenting and socialization processes in humans. Study 1 is a quantitative cross-cultural comparison of grooming practices in two cultural settings: an urban centre in Burma (Myanmar) and an urban centre in the United States. The study uses naturalistic video data of 57 families to analyse grooming behaviours directed at children. A broad range of ages was sampled in each culture to examine the developmental trajectory of grooming behaviours. Results indicate that significant cultural differences exist between Burma and the United States, with Burmese children being groomed by their caregivers more often than U.S. children. Results also indicate that cultural differences in grooming practices begin early and remain constant across age. An unexpected finding was that Burmese families were more variable in their behaviour than U.S. families. Study 2 attempts to explain this variability by using ethnography to describe how sociodemographic changes in Burma are leading to changes in parental values and socialization practices in the schools, but how embodied primary care in the homes appear resistant to change. © 2014 The Authors. International Journal of Psychology published by John Wiley & Sons Ltd on behalf of International Union of Psychological Science.

  5. Grooming and cultural socialization: A mixed method study of caregiving practices in Burma (Myanmar) and the United States†

    Science.gov (United States)

    Thein-Lemelson, Seinenu M

    2015-01-01

    Grooming behaviours are thought to be a crucial aspect of parenting and integral to the sociality of non-human mammals, but there have been few empirical studies on how grooming might be relevant to parenting and socialization processes in humans. Study 1 is a quantitative cross-cultural comparison of grooming practices in two cultural settings: an urban centre in Burma (Myanmar) and an urban centre in the United States. The study uses naturalistic video data of 57 families to analyse grooming behaviours directed at children. A broad range of ages was sampled in each culture to examine the developmental trajectory of grooming behaviours. Results indicate that significant cultural differences exist between Burma and the United States, with Burmese children being groomed by their caregivers more often than U.S. children. Results also indicate that cultural differences in grooming practices begin early and remain constant across age. An unexpected finding was that Burmese families were more variable in their behaviour than U.S. families. Study 2 attempts to explain this variability by using ethnography to describe how sociodemographic changes in Burma are leading to changes in parental values and socialization practices in the schools, but how embodied primary care in the homes appear resistant to change. PMID:25530498

  6. Treatment and electricity harvesting from sulfate/sulfide-containing wastewaters using microbial fuel cell with enriched sulfate-reducing mixed culture

    International Nuclear Information System (INIS)

    Lee, Duu-Jong; Lee, Chin-Yu; Chang, Jo-Shu

    2012-01-01

    Highlights: ► We started up microbial fuel cell (MFC) using enriched sulfate-reducing mixed culture. ► Sulfate-reducing bacteria and anode-respiring bacteria were enriched in anodic biofilms. ► The MFC effectively remove sulfate to elementary sulfur in the presence of lactate. ► The present device can treat sulfate laden wastewaters with electricity harvesting. - Abstract: Anaerobic treatment of sulfate-laden wastewaters can produce excess sulfide, which is corrosive to pipelines and is toxic to incorporated microorganisms. This work started up microbial fuel cell (MFC) using enriched sulfate-reducing mixed culture as anodic biofilms and applied the so yielded MFC for treating sulfate or sulfide-laden wastewaters. The sulfate-reducing bacteria in anodic biofilm effectively reduced sulfate to sulfide, which was then used by neighboring anode respiring bacteria (ARB) as electron donor for electricity production. The presence of organic carbons enhanced MFC performance since the biofilm ARB were mixotrophs that need organic carbon to grow. The present device introduces a route for treating sulfate laden wastewaters with electricity harvesting.

  7. Treatment and electricity harvesting from sulfate/sulfide-containing wastewaters using microbial fuel cell with enriched sulfate-reducing mixed culture

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Duu-Jong, E-mail: cedean@mail.ntust.edu.tw [Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan (China); Lee, Chin-Yu [Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan (China); Chang, Jo-Shu [Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan (China); Center for Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan (China); Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan, Taiwan (China)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer We started up microbial fuel cell (MFC) using enriched sulfate-reducing mixed culture. Black-Right-Pointing-Pointer Sulfate-reducing bacteria and anode-respiring bacteria were enriched in anodic biofilms. Black-Right-Pointing-Pointer The MFC effectively remove sulfate to elementary sulfur in the presence of lactate. Black-Right-Pointing-Pointer The present device can treat sulfate laden wastewaters with electricity harvesting. - Abstract: Anaerobic treatment of sulfate-laden wastewaters can produce excess sulfide, which is corrosive to pipelines and is toxic to incorporated microorganisms. This work started up microbial fuel cell (MFC) using enriched sulfate-reducing mixed culture as anodic biofilms and applied the so yielded MFC for treating sulfate or sulfide-laden wastewaters. The sulfate-reducing bacteria in anodic biofilm effectively reduced sulfate to sulfide, which was then used by neighboring anode respiring bacteria (ARB) as electron donor for electricity production. The presence of organic carbons enhanced MFC performance since the biofilm ARB were mixotrophs that need organic carbon to grow. The present device introduces a route for treating sulfate laden wastewaters with electricity harvesting.

  8. A comparative study on growth performance and biochemical composition of mixed culture of Isochrysis galbana and Chaetoceros calcitrans with monocultures

    Digital Repository Service at National Institute of Oceanography (India)

    Phatarpekar, P.V.; Sreepada, R.A.; Pednekar, C.; Achuthankutty, C.T.

    ., 1977. A mathematical theory for single nutrient competition in continuous cultures of micro-organsims. Soc. Ind. Appl. Math. 32, 366–383. Huntley, M.E., Barthel, K.G., Starr, J.L., 1983. Particle rejection by Calanus pacificus: discrimination between...

  9. Mixing Waters: A Cross Cultural Approach to Developing Guidelines for Fishers and Boaters in the Dhimurru Indigenous Protected Area

    NARCIS (Netherlands)

    Verschuuren, B.; Zylstra, M.; Yunupingu, B.; Verschoor, G.M.

    2014-01-01

    This article demonstrates the importance of indigenous ontologies in cross-cultural or ‘both ways’ coastal conservation management of the Dhimurru Indigenous Protected Area in north east Arnhem Land, Australia. In this action research, selected Yol¿u individuals identified concerns regarding

  10. Methylocapsa aurea sp. nov., a facultative methanotroph possessing a particulate methane monooxygenase, and emended description of the genus Methylocapsa.

    Science.gov (United States)

    Dunfield, Peter F; Belova, Svetlana E; Vorob'ev, Alexey V; Cornish, Sabrina L; Dedysh, Svetlana N

    2010-11-01

    An aerobic, methanotrophic bacterium, designated KYG(T), was isolated from a forest soil in Germany. Cells of strain KYG(T) were Gram-negative, non-motile, slightly curved rods that multiplied by binary fission and produced yellow colonies. The cells contained intracellular granules of poly-β-hydroxybutyrate at each cell pole, a particulate methane monooxygenase (pMMO) and stacks of intracytoplasmic membranes (ICMs) packed in parallel along one side of the cell envelope. Strain KYG(T) grew at pH 5.2-7.2 and 2-33 °C and could fix atmospheric nitrogen under reduced oxygen tension. The major cellular fatty acid was C(18 : 1)ω7c (81.5 %) and the DNA G+C content was 61.4 mol%. Strain KYG(T) belonged to the family Beijerinckiaceae of the class Alphaproteobacteria and was most closely related to the obligate methanotroph Methylocapsa acidiphila B2(T) (98.1 % 16S rRNA gene sequence similarity and 84.7 % pmoA sequence similarity). Unlike Methylocapsa acidiphila B2(T), which grows only on methane and methanol, strain KYG(T) was able to grow facultatively on acetate. Facultative acetate utilization is a characteristic of the methanotrophs of the genus Methylocella, but the genus Methylocella does not produce pMMO or ICMs. Strain KYG(T) differed from Methylocapsa acidiphila B2(T) on the basis of substrate utilization pattern, pigmentation, pH range, cell ultrastructure and efficiency of dinitrogen fixation. Therefore, we propose a novel species, Methylocapsa aurea sp. nov., to accommodate this bacterium. The type strain is KYG(T) (=DSM 22158(T) =VKM B-2544(T)).

  11. Metaproteomic identification of diazotrophic methanotrophs and their localization in root tissues of field-grown rice plants.

    Science.gov (United States)

    Bao, Zhihua; Okubo, Takashi; Kubota, Kengo; Kasahara, Yasuhiro; Tsurumaru, Hirohito; Anda, Mizue; Ikeda, Seishi; Minamisawa, Kiwamu

    2014-08-01

    In a previous study by our group, CH4 oxidation and N2 fixation were simultaneously activated in the roots of wild-type rice plants in a paddy field with no N input; both processes are likely controlled by a rice gene for microbial symbiosis. The present study examined which microorganisms in rice roots were responsible for CH4 oxidation and N2 fixation under the field conditions. Metaproteomic analysis of root-associated bacteria from field-grown rice (Oryza sativa Nipponbare) revealed that nitrogenase complex-containing nitrogenase reductase (NifH) and the alpha subunit (NifD) and beta subunit (NifK) of dinitrogenase were mainly derived from type II methanotrophic bacteria of the family Methylocystaceae, including Methylosinus spp. Minor nitrogenase proteins such as Methylocella, Bradyrhizobium, Rhodopseudomonas, and Anaeromyxobacter were also detected. Methane monooxygenase proteins (PmoCBA and MmoXYZCBG) were detected in the same bacterial group of the Methylocystaceae. Because these results indicated that Methylocystaceae members mediate both CH4 oxidation and N2 fixation, we examined their localization in rice tissues by using catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH). The methanotrophs were localized around the epidermal cells and vascular cylinder in the root tissues of the field-grown rice plants. Our metaproteomics and CARD-FISH results suggest that CH4 oxidation and N2 fixation are performed mainly by type II methanotrophs of the Methylocystaceae, including Methylosinus spp., inhabiting the vascular bundles and epidermal cells of rice roots. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  12. Enrichment of denitrifying methanotrophic bacteria for application after direct low-temperature anaerobic sewage treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kampman, Christel, E-mail: christel.kampman@wur.nl [Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen (Netherlands); Hendrickx, Tim L.G. [Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen (Netherlands); Luesken, Francisca A.; Alen, Theo A. van; Op den Camp, Huub J.M.; Jetten, Mike S.M. [Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Zeeman, Grietje; Buisman, Cees J.N.; Temmink, Hardy [Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen (Netherlands)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer A new concept for low-temperature anaerobic sewage treatment is proposed. Black-Right-Pointing-Pointer In this concept, denitrification and methane oxidation are performed by Methylomirabilis oxyfera. Black-Right-Pointing-Pointer The bacteria were enriched from fresh water sediment using sequencing fed-batch reactors. Black-Right-Pointing-Pointer The volumetric consumption rate has to be increased by an order of magnitude for practical application. Black-Right-Pointing-Pointer Further research should focus on systems with improved biomass retention. - Abstract: Despite many advantages of anaerobic sewage treatment over conventional activated sludge treatment, it has not yet been applied in temperate zones. This is especially because effluent from low-temperature anaerobic treatment contains nitrogen and dissolved methane. The presence of nitrogen and methane offers the opportunity to develop a reactor in which methane is used as electron donor for denitrification. Such a reactor could be used in a new concept for low-temperature anaerobic sewage treatment, consisting of a UASB-digester system, a reactor for denitrification coupled to anaerobic methane oxidation, and a nitritation reactor. In the present study denitrifying methanotrophic bacteria similar to 'Candidatus Methylomirabilis oxyfera' were enriched. Maximum volumetric nitrite consumption rates were 33.5 mg NO{sub 2}{sup -}-N/L d (using synthetic medium) and 37.8 mg NO{sub 2}{sup -}-N/L d (using medium containing effluent from a sewage treatment plant), which are similar to the maximum rate reported so far. Though the goal was to increase the rates, in both reactors, after reaching these maximum rates, volumetric nitrite consumption rates decreased in time. Results indicate biomass washout may have significantly decelerated enrichment. Therefore, to obtain higher volumetric consumption rates, further research should focus on systems with complete biomass

  13. Changes in methane oxidation activity and methanotrophic community composition in saline alkaline soils.

    Science.gov (United States)

    Serrano-Silva, Nancy; Valenzuela-Encinas, César; Marsch, Rodolfo; Dendooven, Luc; Alcántara-Hernández, Rocio J

    2014-05-01

    The soil of the former Lake Texcoco is a saline alkaline environment where anthropogenic drainage in some areas has reduced salt content and pH. Potential methane (CH4) consumption rates were measured in three soils of the former Lake Texcoco with different electrolytic conductivity (EC) and pH, i.e. Tex-S1 a >18 years drained soil (EC 0.7 dS m(-1), pH 8.5), Tex-S2 drained for ~10 years (EC 9.0 dS m(-1), pH 10.3) and the undrained Tex-S3 (EC 84.8 dS m(-1), pH 10.3). An arable soil from Alcholoya (EC 0.7 dS m(-1), pH 6.7), located nearby Lake Texcoco was used as control. Methane oxidation in the soil Tex-S1 (lowest EC and pH) was similar to that in the arable soil from Alcholoya (32.5 and 34.7 mg CH4 kg(-1) dry soil day(-1), respectively). Meanwhile, in soils Tex-S2 and Tex-S3, the potential CH4 oxidation rates were only 15.0 and 12.8 mg CH4 kg(-1) dry soil day(-1), respectively. Differences in CH4 oxidation were also related to changes in the methane-oxidizing communities in these soils. Sequence analysis of pmoA gene showed that soils differed in the identity and number of methanotrophic phylotypes. The Alcholoya soil and Tex-S1 contained phylotypes grouped within the upland soil cluster gamma and the Jasper Ridge, California JR-2 clade. In soil Tex-S3, a phylotype related to Methylomicrobium alcaliphilum was detected.

  14. Enrichment of denitrifying methanotrophic bacteria for application after direct low-temperature anaerobic sewage treatment

    International Nuclear Information System (INIS)

    Kampman, Christel; Hendrickx, Tim L.G.; Luesken, Francisca A.; Alen, Theo A. van; Op den Camp, Huub J.M.; Jetten, Mike S.M.; Zeeman, Grietje; Buisman, Cees J.N.; Temmink, Hardy

    2012-01-01

    Highlights: ► A new concept for low-temperature anaerobic sewage treatment is proposed. ► In this concept, denitrification and methane oxidation are performed by Methylomirabilis oxyfera. ► The bacteria were enriched from fresh water sediment using sequencing fed-batch reactors. ► The volumetric consumption rate has to be increased by an order of magnitude for practical application. ► Further research should focus on systems with improved biomass retention. - Abstract: Despite many advantages of anaerobic sewage treatment over conventional activated sludge treatment, it has not yet been applied in temperate zones. This is especially because effluent from low-temperature anaerobic treatment contains nitrogen and dissolved methane. The presence of nitrogen and methane offers the opportunity to develop a reactor in which methane is used as electron donor for denitrification. Such a reactor could be used in a new concept for low-temperature anaerobic sewage treatment, consisting of a UASB-digester system, a reactor for denitrification coupled to anaerobic methane oxidation, and a nitritation reactor. In the present study denitrifying methanotrophic bacteria similar to ‘Candidatus Methylomirabilis oxyfera’ were enriched. Maximum volumetric nitrite consumption rates were 33.5 mg NO 2 − -N/L d (using synthetic medium) and 37.8 mg NO 2 − -N/L d (using medium containing effluent from a sewage treatment plant), which are similar to the maximum rate reported so far. Though the goal was to increase the rates, in both reactors, after reaching these maximum rates, volumetric nitrite consumption rates decreased in time. Results indicate biomass washout may have significantly decelerated enrichment. Therefore, to obtain higher volumetric consumption rates, further research should focus on systems with complete biomass retention.

  15. Methyloferula stellata gen. nov., sp. nov., an acidophilic, obligately methanotrophic bacterium that possesses only a soluble methane monooxygenase.

    Science.gov (United States)

    Vorobev, Alexey V; Baani, Mohamed; Doronina, Nina V; Brady, Allyson L; Liesack, Werner; Dunfield, Peter F; Dedysh, Svetlana N

    2011-10-01

    Two strains of aerobic methanotrophic bacteria, AR4(T) and SOP9, were isolated from acidic (pH 3.8-4.0) Sphagnum peat bogs in Russia. Another phenotypically similar isolate, strain LAY, was obtained from an acidic (pH 4.0) forest soil in Germany. Cells of these strains were Gram-negative, non-pigmented, non-motile, thin rods that multiplied by irregular cell division and formed rosettes or amorphous cell conglomerates. Similar to Methylocella species, strains AR4(T), SOP9 and LAY possessed only a soluble form of methane monooxygenase (sMMO) and lacked intracytoplasmic membranes. Growth occurred only on methane and methanol; the latter was the preferred growth substrate. mRNA transcripts of sMMO were detectable in cells when either methane or both methane and methanol were available. Carbon was assimilated via the serine and ribulose-bisphosphate (RuBP) pathways; nitrogen was fixed via an oxygen-sensitive nitrogenase. Strains AR4(T), SOP9 and LAY were moderately acidophilic, mesophilic organisms capable of growth between pH 3.5 and 7.2 (optimum pH 4.8-5.2) and at 4-33 °C (optimum 20-23 °C). The major cellular fatty acid was 18 : 1ω7c and the quinone was Q-10. The DNA G+C content was 55.6-57.5 mol%. The isolates belonged to the family Beijerinckiaceae of the class Alphaproteobacteria and were most closely related to the sMMO-possessing methanotrophs of the genus Methylocella (96.4-97.0 % 16S rRNA gene sequence similarity), particulate MMO (pMMO)-possessing methanotrophs of the genus Methylocapsa (96.1-97.0 %), facultative methylotrophs of the genus Methylovirgula (96.1-96.3 %) and non-methanotrophic organotrophs of the genus Beijerinckia (96.5-97.0 %). Phenotypically, strains AR4(T), SOP9 and LAY were most similar to Methylocella species, but differed from members of this genus by cell morphology, greater tolerance of low pH, detectable activities of RuBP pathway enzymes and inability to grow on multicarbon compounds. Therefore, we propose a novel

  16. Methane fluxes and the functional groups of methanotrophs and methanogens in a young Arctic landscape on Disko Island, West Greenland

    DEFF Research Database (Denmark)

    Christiansen, Jesper Riis; Barrera Romero, Alejandro Jose; Jørgensen, Niels O. G.

    2015-01-01

    and activity indicates that the age of an Arctic landscape is not important for the CH4 consumption but can be very important for CH4 production. Considering the prevalence of dry landscapes and contrasting ages of high Arctic soils, our results highlight that well-drained soils should not be overlooked......Arctic soils are known to be important methane (CH4) consumers and sources. This study integrates in situ fluxes of CH4 between upland and wetland soils with potential rates of CH4 oxidation and production as well as abundance and diversity of the methanotrophs and methanogens measured...... as an important component of Arctic net CH4 budget....

  17. Photoautotrophic production of polyhydroxyalkanoates in a synthetic mixed culture of Synechococcus elongatus cscB and Pseudomonas putida cscAB.

    Science.gov (United States)

    Löwe, Hannes; Hobmeier, Karina; Moos, Manuel; Kremling, Andreas; Pflüger-Grau, Katharina

    2017-01-01

    One of the major challenges for the present and future generations is to find suitable substitutes for the fossil resources we rely on today. Cyanobacterial carbohydrates have been discussed as an emerging renewable feedstock in industrial biotechnology for the production of fuels and chemicals, showing promising production rates when compared to crop-based feedstock. However, intrinsic capacities of cyanobacteria to produce biotechnological compounds are limited and yields are low. Here, we present an approach to circumvent these problems by employing a synthetic bacterial co-culture for the carbon-neutral production of polyhydroxyalkanoates (PHAs) from CO 2 . The co-culture consists of two bio - modules : Bio - module I , in which the cyanobacterial strain Synechococcus elongatus cscB fixes CO 2 , converts it to sucrose, and exports it into the culture supernatant; and bio - module II , where this sugar serves as C-source for Pseudomonas putida cscAB and is converted to PHAs that are accumulated in the cytoplasm. By applying a nitrogen-limited process, we achieved a maximal PHA production rate of 23.8 mg/(L day) and a maximal titer of 156 mg/L. We will discuss the present shortcomings of the process and show the potential for future improvement. These results demonstrate the feasibility of mixed cultures of S. elongatus cscB and P. putida cscAB for PHA production, making room for the cornucopia of possible products that are described for P. putida . The construction of more efficient sucrose-utilizing P. putida phenotypes and the optimization of process conditions will increase yields and productivities and eventually close the gap in the contemporary process. In the long term, the co-culture may serve as a platform process, in which P. putida is used as a chassis for the implementation of synthetic metabolic pathways for biotechnological production of value-added products.

  18. Inhibitory effects of meju prepared with mixed starter cultures on azoxymethane and dextran sulfate sodium-induced colon carcinogenesis in mice

    Directory of Open Access Journals (Sweden)

    Ji-Kang Jeong

    2012-01-01

    Full Text Available Backgrounds: Meju is the main ingredient and the starter culture of traditional Korean fermented soybean foods; these fermented soybean products are well-known for their various health benefits, including anticancer effects. We developed the grain-type meju using probiotic mixed starter cultures to improve the qualities and functionalities of fermented soybean products, as well as the meju itself. In this study, the inhibitory effects of the grain-type meju were investigated in azoxymethane (AOM and dextran sulfate sodium (DSS-induced colon carcinogenesis mice model. Materials and Methods: AOM and DSS colon carcinogenesis was induced in female C57BL/6 mice and meju was orally administered for 4 weeks. The body weight, colon length, and colon weight of mice were determined, and colonic tissues were histologically observed. The serum levels of proinflammatory cytokines and the levels of inflammation- and apoptosis-related genes in colonic tissue were also analyzed. Results: The administration of meju using probiotic mixed starter cultures ameliorated the symptoms of colon cancer and reduced number of neoplasia, and reduced serum proinflammatory cytokine levels and iNOS and COX-2 expression levels in colonic tissue. It increased Bax and reduced Bcl-2 expression levels and increased p21 and p53 expression in colonic tissues. Conclusion: The meju showed inhibitory effects on the progression of colon cancer induced by AOM and DSS by ameliorating the symptoms of colon cancer, reducing the number of neoplasias and regulating proinflammatory cytokine levels and the expressions of inflammation- and apoptosis-related genes in the colonic tissue.

  19. Using consumer perspectives to inform the cultural adaptation of psychological treatments for depression: a mixed methods study from South Asia.

    Science.gov (United States)

    Aggarwal, Neil Krishan; Balaji, Madhumitha; Kumar, Shuba; Mohanraj, Rani; Rahman, Atif; Verdeli, Helena; Araya, Ricardo; Jordans, M J D; Chowdhary, Neerja; Patel, Vikram

    2014-07-01

    Integrating consumer perspectives in developing and adapting psychological treatments (PTs) can enhance their acceptability in diverse cultural contexts. To describe the explanatory models (EMs) of depression in South Asia with the goal of informing the content of culturally appropriate PTs for this region. Two methods were used: a systematic review of published literature on the EMs of depression in South Asia; and in-depth interviews with persons with depression and family caregivers in two sites in India. Findings from both were analysed independently and then triangulated. There were 19 studies meeting our inclusion criteria. Interviews were conducted with 27 patients and 10 caregivers. Findings were grouped under four broad categories: illness descriptions, perceived impact, causal beliefs and self-help forms of coping. Depression was characterised predominantly by somatic complaints, stress, low mood, and negative and ruminative thoughts. Patients experienced disturbances in interpersonal relationships occupational functioning, and stigma. Negative life events, particularly relationship difficulties, were perceived as the main cause. Patients mostly engaged in distracting activities, religious practices, and received support from family and friends to cope with the illness. The primary data are entirely from India but the studies from the literature review covering South Asia are consistent with these findings. This study also does not include literature in local languages or explore how consumer perspectives change over time. EMs can inform cultural adaptations to PTs for depression in South Asia by defining target outcomes, content for psycho-education, and culturally appropriate treatment strategies. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  20. Novel chelating agents for iron, manganese, zinc, and copper mixed fertilisation in high pH soil-less cultures.

    Science.gov (United States)

    López-Rayo, Sandra; Nadal, Paloma; Lucena, Juan J

    2016-03-15

    Studies about simultaneous fertilisation with several micronutrients have increased in recent years, as Fe, Mn and Zn deficiencies may appear in the same culture conditions. In fertigation, the replacement of sulfates by synthetic chelates is essential in areas with high pH irrigation water and substrates. Ethylenediamine-N-(2-hydroxyphenylacetic acid)-N'-(4-hydroxyphenylacetic acid) (o,p-EDDHA) and ethylenediamine disuccinic acid (EDDS) are novel chelating agents whose efficacy in simultaneous fertilisation of Zn, Mn and Cu is unknown. This work evaluates the effectiveness of both ligands compared to traditional ligands (EDTA, HEEDTA and DTPA) applied as micronutrient chelate mixtures to soybean and navy bean plants grown in soil-less cultures at high pH by analysing the SPAD and micronutrient nutritional status, including the Composition Nutritional Diagnosis (CND) analysis tool. The application of micronutrients using o,p-EDDHA was more effective in providing Mn and Zn than traditional ligands or sulfates. The application using EDDS increased the Zn nutrition. The results are well correlated with the chemical stability of the formulations. The combined application of Mn and Zn as o,p-EDDHA chelates can represent a more effective source than traditional chelates in micronutrient fertiliser mixtures in soil-less cultures at a high pH. © 2015 Society of Chemical Industry.

  1. Cyanuric acid biodegradation by a mixed bacterial culture of Agrobacterium tumefaciens and Acinetobacter sp. in a packed bed biofilm reactor.

    Science.gov (United States)

    Galíndez-Nájera, S P; Llamas-Martínez, M A; Ruiz-Ordaz, N; Juárez-Ramírez, C; Mondragón-Parada, M E; Ahuatzi-Chacón, D; Galíndez-Mayer, J

    2009-02-01

    Cyanuric acid (1,3,5-triazine-2,4,6-triol [OOOT]) is a common biodegradation byproduct of triazinic herbicides, frequently accumulated in soils or water when supplementary carbon sources are absent. A binary bacterial culture able to degrade OOOT was selected through a continuous selection process accomplished in a chemostat fed with a mineral salt (MS) medium containing cyanuric acid as the sole carbon and nitrogen source. By sequence comparison of their 16S rDNA amplicons, bacterial strains were identified as Agrobacterium tumefaciens, and Acinetobacter sp. When the binary culture immobilized in a packed bed reactor (PBR) was fed with MS medium containing OOOT (50 mg L(-1)), its removal efficiencies were about 95%; when it was fed with OOOT plus glucose (120 mg L(-1)) as a supplementary carbon source, its removal efficiencies were closer to 100%. From sessile cells, attached to PBR porous support, or free cells present in the outflowing medium, DNA was extracted and used for Random Amplification of Polymorphic DNA analysis. Electrophoretic patterns obtained were compared to those of pure bacterial strains, a clear predominance of A. tumefaciens in PBR was observed. Although in continuous suspended cell culture, a stable binary community could be maintained, the attachment capability of A. tumefaciens represented a selective advantage over Acinetobacter sp. in the biofilm reactor, favoring its predominance in the porous stone support.

  2. Stochastic models to study the impact of mixing on a fed-batch culture of Saccharomyces cerevisiae.

    Science.gov (United States)

    Delvigne, F; Lejeune, A; Destain, J; Thonart, P

    2006-01-01

    The mechanisms of interaction between microorganisms and their environment in a stirred bioreactor can be modeled by a stochastic approach. The procedure comprises two submodels: a classical stochastic model for the microbial cell circulation and a Markov chain model for the concentration gradient calculus. The advantage lies in the fact that the core of each submodel, i.e., the transition matrix (which contains the probabilities to shift from a perfectly mixed compartment to another in the bioreactor representation), is identical for the two cases. That means that both the particle circulation and fluid mixing process can be analyzed by use of the same modeling basis. This assumption has been validated by performing inert tracer (NaCl) and stained yeast cells dispersion experiments that have shown good agreement with simulation results. The stochastic model has been used to define a characteristic concentration profile experienced by the microorganisms during a fermentation test performed in a scale-down reactor. The concentration profiles obtained in this way can explain the scale-down effect in the case of a Saccharomyces cerevisiae fed-batch process. The simulation results are analyzed in order to give some explanations about the effect of the substrate fluctuation dynamics on S. cerevisiae.

  3. Dynamics of biofilm formation by Listeria monocytogenes on stainless steel under mono-species and mixed-culture simulated fish processing conditions and chemical disinfection challenges.

    Science.gov (United States)

    Papaioannou, Eleni; Giaouris, Efstathios D; Berillis, Panagiotis; Boziaris, Ioannis S

    2018-02-21

    The progressive ability of a six-strains L. monocytogenes cocktail to form biofilm on stainless steel (SS), under fish-processing simulated conditions, was investigated, together with the biocide tolerance of the developed sessile communities. To do this, the pathogenic bacteria were left to form biofilms on SS coupons incubated at 15°C, for up to 240h, in periodically renewable model fish juice substrate, prepared by aquatic extraction of sea bream flesh, under both mono-species and mixed-culture conditions. In the latter case, L. monocytogenes cells were left to produce biofilms together with either a five-strains cocktail of four Pseudomonas species (fragi, savastanoi, putida and fluorescens), or whole fish indigenous microflora. The biofilm populations of L. monocytogenes, Pseudomonas spp., Enterobacteriaceae, H 2 S producing and aerobic plate count (APC) bacteria, both before and after disinfection, were enumerated by selective agar plating, following their removal from surfaces through bead vortexing. Scanning electron microscopy was also applied to monitor biofilm formation dynamics and anti-biofilm biocidal actions. Results revealed the clear dominance of Pseudomonas spp. bacteria in all the mixed-culture sessile communities throughout the whole incubation period, with the in parallel sole presence of L. monocytogenes cells to further increase (ca. 10-fold) their sessile growth. With respect to L. monocytogenes and under mono-species conditions, its maximum biofilm population (ca. 6logCFU/cm 2 ) was reached at 192h of incubation, whereas when solely Pseudomonas spp. cells were also present, its biofilm formation was either slightly hindered or favored, depending on the incubation day. However, when all the fish indigenous microflora was present, biofilm formation by the pathogen was greatly hampered and never exceeded 3logCFU/cm 2 , while under the same conditions, APC biofilm counts had already surpassed 7logCFU/cm 2 by the end of the first 96h of

  4. Unraveling the Physiological Roles of the Cyanobacterium Geitlerinema sp. BBD and Other Black Band Disease Community Members through Genomic Analysis of a Mixed Culture

    Science.gov (United States)

    Den Uyl, Paul A.; Richardson, Laurie L.; Jain, Sunit

    2016-01-01

    Black band disease (BBD) is a cyanobacterial-dominated polymicrobial mat that propagates on and migrates across coral surfaces, necrotizing coral tissue. Culture-based laboratory studies have investigated cyanobacteria and heterotrophic bacteria isolated from BBD, but the metabolic potential of various BBD microbial community members and interactions between them remain poorly understood. Here we report genomic insights into the physiological and metabolic potential of the BBD-associated cyanobacterium Geitlerinema sp. BBD 1991 and six associated bacteria that were also present in the non-axenic culture. The essentially complete genome of Geitlerinema sp. BBD 1991 contains a sulfide quinone oxidoreductase gene for oxidation of sulfide, suggesting a mechanism for tolerating the sulfidic conditions of BBD mats. Although the operon for biosynthesis of the cyanotoxin microcystin was surprisingly absent, potential relics were identified. Genomic evidence for mixed-acid fermentation indicates a strategy for energy metabolism under the anaerobic conditions present in BBD during darkness. Fermentation products may supply carbon to BBD heterotrophic bacteria. Among the six associated bacteria in the culture, two are closely related to organisms found in culture-independent studies of diseased corals. Their metabolic pathways for carbon and sulfur cycling, energy metabolism, and mechanisms for resisting coral defenses suggest adaptations to the coral surface environment and biogeochemical roles within the BBD mat. Polysulfide reductases were identified in a Flammeovirgaceae genome (Bacteroidetes) and the sox pathway for sulfur oxidation was found in the genome of a Rhodospirillales bacterium (Alphaproteobacteria), revealing mechanisms for sulfur cycling, which influences virulence of BBD. Each genomic bin possessed a pathway for conserving energy from glycerol degradation, reflecting adaptations to the glycerol-rich coral environment. The presence of genes for detoxification

  5. Unraveling the Physiological Roles of the Cyanobacterium Geitlerinema sp. BBD and Other Black Band Disease Community Members through Genomic Analysis of a Mixed Culture.

    Science.gov (United States)

    Den Uyl, Paul A; Richardson, Laurie L; Jain, Sunit; Dick, Gregory J

    2016-01-01

    Black band disease (BBD) is a cyanobacterial-dominated polymicrobial mat that propagates on and migrates across coral surfaces, necrotizing coral tissue. Culture-based laboratory studies have investigated cyanobacteria and heterotrophic bacteria isolated from BBD, but the metabolic potential of various BBD microbial community members and interactions between them remain poorly understood. Here we report genomic insights into the physiological and metabolic potential of the BBD-associated cyanobacterium Geitlerinema sp. BBD 1991 and six associated bacteria that were also present in the non-axenic culture. The essentially complete genome of Geitlerinema sp. BBD 1991 contains a sulfide quinone oxidoreductase gene for oxidation of sulfide, suggesting a mechanism for tolerating the sulfidic conditions of BBD mats. Although the operon for biosynthesis of the cyanotoxin microcystin was surprisingly absent, potential relics were identified. Genomic evidence for mixed-acid fermentation indicates a strategy for energy metabolism under the anaerobic conditions present in BBD during darkness. Fermentation products may supply carbon to BBD heterotrophic bacteria. Among the six associated bacteria in the culture, two are closely related to organisms found in culture-independent studies of diseased corals. Their metabolic pathways for carbon and sulfur cycling, energy metabolism, and mechanisms for resisting coral defenses suggest adaptations to the coral surface environment and biogeochemical roles within the BBD mat. Polysulfide reductases were identified in a Flammeovirgaceae genome (Bacteroidetes) and the sox pathway for sulfur oxidation was found in the genome of a Rhodospirillales bacterium (Alphaproteobacteria), revealing mechanisms for sulfur cycling, which influences virulence of BBD. Each genomic bin possessed a pathway for conserving energy from glycerol degradation, reflecting adaptations to the glycerol-rich coral environment. The presence of genes for detoxification

  6. Unraveling the Physiological Roles of the Cyanobacterium Geitlerinema sp. BBD and Other Black Band Disease Community Members through Genomic Analysis of a Mixed Culture.

    Directory of Open Access Journals (Sweden)

    Paul A Den Uyl

    Full Text Available Black band disease (BBD is a cyanobacterial-dominated polymicrobial mat that propagates on and migrates across coral surfaces, necrotizing coral tissue. Culture-based laboratory studies have investigated cyanobacteria and heterotrophic bacteria isolated from BBD, but the metabolic potential of various BBD microbial community members and interactions between them remain poorly understood. Here we report genomic insights into the physiological and metabolic potential of the BBD-associated cyanobacterium Geitlerinema sp. BBD 1991 and six associated bacteria that were also present in the non-axenic culture. The essentially complete genome of Geitlerinema sp. BBD 1991 contains a sulfide quinone oxidoreductase gene for oxidation of sulfide, suggesting a mechanism for tolerating the sulfidic conditions of BBD mats. Although the operon for biosynthesis of the cyanotoxin microcystin was surprisingly absent, potential relics were identified. Genomic evidence for mixed-acid fermentation indicates a strategy for energy metabolism under the anaerobic conditions present in BBD during darkness. Fermentation products may supply carbon to BBD heterotrophic bacteria. Among the six associated bacteria in the culture, two are closely related to organisms found in culture-independent studies of diseased corals. Their metabolic pathways for carbon and sulfur cycling, energy metabolism, and mechanisms for resisting coral defenses suggest adaptations to the coral surface environment and biogeochemical roles within the BBD mat. Polysulfide reductases were identified in a Flammeovirgaceae genome (Bacteroidetes and the sox pathway for sulfur oxidation was found in the genome of a Rhodospirillales bacterium (Alphaproteobacteria, revealing mechanisms for sulfur cycling, which influences virulence of BBD. Each genomic bin possessed a pathway for conserving energy from glycerol degradation, reflecting adaptations to the glycerol-rich coral environment. The presence of genes

  7. Evidence for cooperative mineralization of diuron by Arthrobacter sp. BS2 and Achromobacter sp. SP1 isolated from a mixed culture enriched from diuron exposed environments.

    Science.gov (United States)

    Devers-Lamrani, Marion; Pesce, Stéphane; Rouard, Nadine; Martin-Laurent, Fabrice

    2014-12-01

    Diuron was found to be mineralized in buffer strip soil (BS) and in the sediments (SED) of the Morcille river in the Beaujolais vineyard repeatedly treated with this herbicide. Enrichment cultures from BS and SED samples led to the isolation of three bacterial strains transforming diuron to 3,4-dichloroaniline (3,4-DCA) its aniline derivative. 16S rRNA sequencing revealed that they belonged to the genus Arthrobacter (99% of similarity to Arthrobacter globiformis strain K01-01) and were designated as Arthrobacter sp. BS1, BS2 and SED1. Diuron-degrading potential characterized by sequencing of the puhA gene, characterizing the diuron-degradaing potential, revealed 99% similarity to A. globiformis strain D47 puhA gene isolated a decade ago in the UK. These isolates were also able to use chlorotoluron for their growth. Although able to degrade linuron and monolinuron to related aniline derivatives they were not growing on them. Enrichment cultures led to the isolation of a strain from the sediments entirely degrading 3,4-DCA. 16S rRNA sequence analysis showed that it was affiliated to the genus Achromobacter (99% of similarity to Achromobacter sp. CH1) and was designated as Achromobacter sp. SP1. The dcaQ gene encoding enzyme responsible for the transformation of 3,4-DCA to chlorocatechol was found in SP1 with 99% similarity to that of Comamonas testosteroni WDL7. This isolate also used for its growth a range of anilines (3-chloro-4-methyl-aniline, 4-isopropylaniline, 4-chloroaniline, 3-chloroaniline, 4-bromoaniline). The mixed culture composed of BS2 and SP1 strains entirely mineralizes (14)C-diuron to (14)CO2. Diuron-mineralization observed in the enrichment culture could result from the metabolic cooperation between these two populations. Copyright © 2014. Published by Elsevier Ltd.

  8. Effect of methanogenic substrates on anaerobic oxidation of methane and sulfate reduction by an anaerobic methanotrophic enrichment.

    KAUST Repository

    Meulepas, Roel J W

    2010-05-06

    Anaerobic oxidation of methane (AOM) coupled to sulfate reduction (SR) is assumed to be a syntrophic process, in which methanotrophic archaea produce an interspecies electron carrier (IEC), which is subsequently utilized by sulfate-reducing bacteria. In this paper, six methanogenic substrates are tested as candidate-IECs by assessing their effect on AOM and SR by an anaerobic methanotrophic enrichment. The presence of acetate, formate or hydrogen enhanced SR, but did not inhibit AOM, nor did these substrates trigger methanogenesis. Carbon monoxide also enhanced SR but slightly inhibited AOM. Methanol did not enhance SR nor did it inhibit AOM, and methanethiol inhibited both SR and AOM completely. Subsequently, it was calculated at which candidate-IEC concentrations no more Gibbs free energy can be conserved from their production from methane at the applied conditions. These concentrations were at least 1,000 times lower can the final candidate-IEC concentration in the bulk liquid. Therefore, the tested candidate-IECs could not have been produced from methane during the incubations. Hence, acetate, formate, methanol, carbon monoxide, and hydrogen can be excluded as sole IEC in AOM coupled to SR. Methanethiol did inhibit AOM and can therefore not be excluded as IEC by this study.

  9. Different culture conditions affect the growth of human tendon stem/progenitor cells (TSPCs) within a mixed tendon cells (TCs) population.

    Science.gov (United States)

    Viganò, M; Perucca Orfei, C; Colombini, A; Stanco, D; Randelli, P; Sansone, V; de Girolamo, L

    2017-12-01

    Tendon resident cells (TCs) are a mixed population made of terminally differentiated tenocytes and tendon stem/progenitor cells (TSPCs). Since the enrichment of progenitors proportion could enhance the effectiveness of treatments based on these cell populations, the interest on the effect of culture conditions on the TSPCs is growing. In this study the clonal selection and the culture in presence or absence of basic fibroblast growth factor (bFGF) were used to assess their influences on the stemness properties and phenotype specific features of tendon cells. Cells cultured with the different methods were analyzed in terms of clonogenic and differentiation abilities, stem and tendon specific genes expression and immunophenotype at passage 2 and passage 4. The clonal selection allowed to isolate cells with a higher multi-differentiation potential, but at the same time a lower proliferation rate in comparison to the whole population. Moreover, the clones express a higher amounts of stemness marker OCT4 and tendon specific transcription factor Scleraxis (SCX) mRNA, but a lower level of decorin (DCN). On the other hand, the number of cells obtained by clonal selection was extremely low and most of the clones were unable to reach a high number of passages in cultures. The presence of bFGF influences TCs morphology, enhance their proliferation rate and reduce their clonogenic ability. Interestingly, the expression of CD54, a known mesenchymal stem cell marker, is reduced in presence of bFGF at early passages. Nevertheless, bFGF does not affect the chondrogenic and osteogenic potential of TCs and the expression of tendon specific markers, while it was able to downregulate the OCT4 expression. This study showed that clonal selection enhance progenitors content in TCs populations, but the extremely low number of cells produced with this method could represent an insurmountable obstacle to its application in clinical approaches. We observed that the addition of bFGF to the

  10. T-cell activation. VI. Inhibitory and stimulatory effects of anti-major histocompatibility complex class I antibodies in allogeneic mixed lymphocyte culture

    DEFF Research Database (Denmark)

    Röpke, M; Röpke, C; Claesson, Mogens Helweg

    1993-01-01

    Murine T splenocytes stimulated in primary allogeneic mixed lymphocyte culture (MLC) were incubated with soluble anti-major histocompatibility complex (MHC) class I monoclonal antibodies. These antibodies induced inhibition in the cytotoxicity of the responding population and this inhibition...... was not dependent on the domain on class I molecules recognized by the antibodies. Cross-reactivity of the antibodies between the responder and stimulating cell population caused a marked reduction in the inhibitory effect compared to systems where no such cross-reactivity was present. Saturating levels...... of the antibodies caused a reduction in generation of T-cell cytotoxicity, whereas low concentrations stimulated the same response. These results demonstrate that the MHC class I molecules of T cells are of significant importance in antigen-induced signal transduction....

  11. Age- and dose-related alteration of in vitro mixed lymphocyte culture response of blood lymphocytes from A-bomb survivors

    International Nuclear Information System (INIS)

    Akiyama, Mitoshi; Zhou, Ou-Liang; Kusunoki, Yoichiro; Kyoizumi, Seishi; Kohno, Nobuoki; Akiba, Suminori; Delongchamp, R.R.

    1988-07-01

    The responsiveness of peripheral blood lymphocytes to allogenic antigens in mixed lymphocyte culture (MLC) was measured in 139 atomic bomb survivors. The study revealed a significant decrease in MLC with increasing dose of previous radiation exposure. This decline was remarkable in the survivors who were older than 15 at the time of the bomb (ATB). The results suggest a possible relationship between the recovery of T-cell-related function and the thymic function which processes mature T-cells for the immune system. Thus it may be that, in the advanced age ATB group, the thymus function has started to involute allowing less recovery of T-cell function compared to young survivors who have adequate processing T-cell activity. (author)

  12. Comparison of Different Strategies for Selection/Adaptation of Mixed Microbial Cultures Able to Ferment Crude Glycerol Derived from Second-Generation Biodiesel

    DEFF Research Database (Denmark)

    Varrone, Cristiano; Heggeset, T. M. B.; Le, S. B.

    2015-01-01

    Objective of this study was the selection and adaptation of mixed microbial cultures (MMCs), able to ferment crude glycerol generated from animal fat-based biodiesel and produce building-blocks and green chemicals. Various adaptation strategies have been investigated for the enrichment of suitable...... Control. The adaptation of activated sludge inoculum was performed successfully and continued unhindered for several months. The best results showed a substrate degradation efficiency of almost 100% (about 10 g/L glycerol in 21 h) and different dominant metabolic products were obtained, depending...... on the selection strategy (mainly 1,3-propanediol, ethanol, or butyrate). On the other hand, anaerobic sludge exhibited inactivation after a few transfers. To circumvent this problem, fed-batch mode was used as an alternative adaptation strategy, which led to effective substrate degradation and high 1...

  13. Consolidated bioprocessing of microalgal biomass to carboxylates by a mixed culture of cow rumen bacteria using anaerobic sequencing batch reactor (ASBR).

    Science.gov (United States)

    Zhao, Baisuo; Liu, Jie; Frear, Craig; Holtzapple, Mark; Chen, Shulin

    2016-12-01

    This study employed mixed-culture consolidated bioprocessing (CBP) to digest microalgal biomass in an anaerobic sequencing batch reactor (ASBR). The primary objectives are to evaluate the impact of hydraulic residence time (HRT) on the productivity of carboxylic acids and to characterize the bacterial community. HRT affects the production rate and patterns of carboxylic acids. For the 5-L laboratory-scale fermentation, a 12-day HRT was selected because it offered the highest productivity of carboxylic acids and it synthesized longer chains. The variability of the bacterial community increased with longer HRT (R 2 =0.85). In the 5-L laboratory-scale fermentor, the most common phyla were Firmicutes (58.3%), Bacteroidetes (27.4%), and Proteobacteria (11.9%). The dominant bacterial classes were Clostridia (29.8%), Bacteroidia (27.4%), Tissierella (26.2%), and Betaproteobacteria (8.9%). Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Exploring the selective lactic acid production from food waste in uncontrolled pH mixed culture fermentations using different reactor configurations.

    Science.gov (United States)

    Bonk, Fabian; Bastidas-Oyanedel, Juan-Rodrigo; Yousef, Ahmed F; Schmidt, Jens Ejbye

    2017-08-01

    Carboxylic acid production from food waste by mixed culture fermentation is an important future waste management option. Obstacles for its implementation are the need of pH control, and a broad fermentation product spectrum leading to increased product separation costs. To overcome these obstacles, the selective production of lactic acid (LA) from model food waste by uncontrolled pH fermentation was tested using different reactor configurations. Batch experiments, semi-continuously fed reactors and a percolation system reached LA concentrations of 32, 16 and 15gCOD LA /L, respectively, with selectivities of 93%, 84% and 75% on COD base, respectively. The semi-continuous reactor was dominated by Lactobacillales. Our techno-economic analysis suggests that LA production from food waste can be economically feasible, with LA recovery and low yields remaining as major obstacles. To solve both problems, we successfully applied in-situ product extraction using activated carbon. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Effects of Pride and Regret on Geriatric Depression: A Cross-Cultural Study With Mixed-Methods Approaches.

    Science.gov (United States)

    Lee, Othelia E; Ryu, Seungah

    2018-03-01

    Pride and regret are self-conscious emotions that develop later in life and become a source of emotional struggle. This cross-cultural study examined the effect of the content and intensity of self-conscious emotions on Geriatric Depression Scale (GDS) scores. Among a convenience sample of 234 older adults (130 in the United States and 104 in South Korea), the contents and intensities of both life regrets and pride were examined. Although a greater variety of regrets was cited by Americans, overall Korean respondents reported higher intensity of regret. Regrets that were related to leisure and addiction among Americans and health and career among Koreans were predictors of the GDS scores. Pride in leisure activities for Americans and altruism among Koreans could alleviate depression. While regrets and pride explained a small amount of the variance in the GDS scores, current life stressors greatly contributed to geriatric depression.

  16. Acetate consumption in anoxic marine sediments: Identification of key players using mixed pure cultures and sediment incubations

    DEFF Research Database (Denmark)

    Na, Hyunsoo

    . While we did not find methanogens to be involved in acetate consumption with sediment incubations, the results from co-culture experiments show that syntrophic growth may allow aceticlastic methanogens to co-exist with sulfate-reducing bacteria in anoxic, sulfate-rich marine environments....... are largely unknown. The main goal of my PhD project was to identify acetate consumers in sulfate-reducing sediments of Aarhus Bay, Denmark. More specifically, we addressed the hypothesis if sulfate-reducing bacteria and methanogenic archaea can oxidize acetate in syntrophy. First, we examined the changes...... sulfate for a year were comparable to those of sediment incubated with high sulfate, on phylum/class levels, but within Deltaproteobacteria, certain sulfate reducers such as Desulfobacterium anilini was found only with low sulfate. In continuous flow-through reactors, bacteria mainly involved in sulfur...

  17. Modification of growth medium of mixed-culture species of microalgae isolated from southern java coastal region

    Directory of Open Access Journals (Sweden)

    Sudibyo Hanifrahmawan

    2018-01-01

    Full Text Available Globally, there is growing interest in microalgae as production organisms. Microalgae contain lipids (oil, proteins and carbohydrates (sugars, and, especially marine algae have been used as food and feed for centuries. Recently, production cost reduction related to the supply of growth nutrients is necessary to make it profitable. Therefore, utilization of molasses, a byproduct of sugar production, as the natural carbon, macronutrients, and micronutrients sources can be helpful. The analysis showed that the content of sucrose, glucose, fructose, potassium, zinc, and magnesium was 68.4% w/w, 18.5% w/w, and 13.1% w/w, 5.5% w/w, 3.91 ppm, and 1,370 ppm respectively. This work aimed to determine the effect of molasses addition to the physio-chemical properties of multi-culture species of microalgae isolated from southern Java coastal region in Indonesia grown under mixotrophic culture. The cultivation in this work used medium which was self-formulated by the authors consisting of NaNO3 (5 mL/L, H3BO3 (1 mL/L, EDTA (1 mL/L, N2H2PO4 (5 mL/L, FeSO4 (1 mL/L, MgSO4 (1 mL/L, NaCl (1 mL/L, micronutrients (1 mL/L, vitamin B1 (1 mL/L, and vitamin B12 (1 mL/L in 500 mL of water. The medium will be treated to have molasses concentration of 0.05% v/v, 0.15% v/v, 0.25% v/v, 0.35% v/v, and 0.45% v/v.

  18. A Clostridium Group IV Species Dominates and Suppresses a Mixed Culture Fermentation by Tolerance to Medium Chain Fatty Acids Products

    Science.gov (United States)

    Andersen, Stephen J.; De Groof, Vicky; Khor, Way Cern; Roume, Hugo; Props, Ruben; Coma, Marta; Rabaey, Korneel

    2017-01-01

    A microbial community is engaged in a complex economy of cooperation and competition for carbon and energy. In engineered systems such as anaerobic digestion and fermentation, these relationships are exploited for conversion of a broad range of substrates into products, such as biogas, ethanol, and carboxylic acids. Medium chain fatty acids (MCFAs), for example, hexanoic acid, are valuable, energy dense microbial fermentation products, however, MCFA tend to exhibit microbial toxicity to a broad range of microorganisms at low concentrations. Here, we operated continuous mixed population MCFA fermentations on biorefinery thin stillage to investigate the community response associated with the production and toxicity of MCFA. In this study, an uncultured species from the Clostridium group IV (related to Clostridium sp. BS-1) became enriched in two independent reactors that produced hexanoic acid (up to 8.1 g L−1), octanoic acid (up to 3.2 g L−1), and trace concentrations of decanoic acid. Decanoic acid is reported here for the first time as a possible product of a Clostridium group IV species. Other significant species in the community, Lactobacillus spp. and Acetobacterium sp., generate intermediates in MCFA production, and their collapse in relative abundance resulted in an overall production decrease. A strong correlation was present between the community composition and both the hexanoic acid concentration (p = 0.026) and total volatile fatty acid concentration (p = 0.003). MCFA suppressed species related to Clostridium sp. CPB-6 and Lactobacillus spp. to a greater extent than others. The proportion of the species related to Clostridium sp. BS-1 over Clostridium sp. CPB-6 had a strong correlation with the concentration of octanoic acid (p = 0.003). The dominance of this species and the increase in MCFA resulted in an overall toxic effect on the mixed community, most significantly on the Lactobacillus spp., which resulted in a decrease in total

  19. Illumina sequencing-based analysis of a microbial community enriched under anaerobic methane oxidation condition coupled to denitrification revealed coexistence of aerobic and anaerobic methanotrophs.

    Science.gov (United States)

    Siniscalchi, Luciene Alves Batista; Leite, Laura Rabelo; Oliveira, Guilherme; Chernicharo, Carlos Augusto Lemos; de Araújo, Juliana Calabria

    2017-07-01

    Methane is produced in anaerobic environments, such as reactors used to treat wastewaters, and can be consumed by methanotrophs. The composition and structure of a microbial community enriched from anaerobic sewage sludge under methane-oxidation condition coupled to denitrification were investigated. Denaturing gradient gel electrophoresis (DGGE) analysis retrieved sequences of Methylocaldum and Chloroflexi. Deep sequencing analysis revealed a complex community that changed over time and was affected by methane concentration. Methylocaldum (8.2%), Methylosinus (2.3%), Methylomonas (0.02%), Methylacidiphilales (0.45%), Nitrospirales (0.18%), and Methanosarcinales (0.3%) were detected. Despite denitrifying conditions provided, Nitrospirales and Methanosarcinales, known to perform anaerobic methane oxidation coupled to denitrification (DAMO) process, were in very low abundance. Results demonstrated that aerobic and anaerobic methanotrophs coexisted in the reactor together with heterotrophic microorganisms, suggesting that a diverse microbial community was important to sustain methanotrophic activity. The methanogenic sludge was a good inoculum to enrich methanotrophs, and cultivation conditions play a selective role in determining community composition.

  20. Detection and enumeration of methanotrophs in acidic Sphagnum peat by 16S rRNA fluorescence in situ hybridization, including the use of newly developed oligonucleotide probes for Methylocella palustris.

    Science.gov (United States)

    Dedysh, S N; Derakshani, M; Liesack, W

    2001-10-01

    Two 16S rRNA-targeted oligonucleotide probes, Mcell-1026 and Mcell-181, were developed for specific detection of the acidophilic methanotroph Methylocella palustris using fluorescence in situ hybridization (FISH). The fluorescence signal of probe Mcell-181 was enhanced by its combined application with the oligonucleotide helper probe H158. Mcell-1026 and Mcell-181, as well as 16S rRNA oligonucleotide probes with reported group specificity for either type I methanotrophs (probes M-84 and M-705) or the Methylosinus/Methylocystis group of type II methanotrophs (probes MA-221 and M-450), were used in FISH to determine the abundance of distinct methanotroph groups in a Sphagnum peat sample of pH 4.2. M. palustris was enumerated at greater than 10(6) cells per g of peat (wet weight), while the detectable population size of type I methanotrophs was three orders of magnitude below the population level of M. palustris. The cell counts with probe MA-221 suggested that only 10(4) type II methanotrophs per g of peat (wet weight) were present, while the use of probe M-450 revealed more than 10(6) type II methanotroph cells per g of the same samples. This discrepancy was due to the fact that probe M-450 targets almost all currently known strains of Methylosinus and Methylocystis, whereas probe MA-221, originally described as group specific, does not detect a large proportion of Methylocystis strains. The total number of methanotrophic bacteria detected by FISH was 3.0 (+/-0.2) x 10(6) cells per g (wet weight) of peat. This was about 0.8% of the total bacterial cell number. Thus, our study clearly suggests that M. palustris and a defined population of Methylocystis spp. were the predominant methanotrophs detectable by FISH in an acidic Sphagnum peat bog.

  1. Effect of Long Time Oxygen Exposure on Power Generation of Microbial Fuel Cell with Enriched Mixed Culture

    International Nuclear Information System (INIS)

    Mimi Hani Abu Bakar; Mimi Hani Abu Bakar; Mimi Hani Abu Bakar; Pasco, N.F.; Gooneratne, R.; Hong, K.B.; Hong, K.B.; Hong, K.B.

    2016-01-01

    In this study, we are interested in the effect of long time exposure of the microbial fuel cells (MFCs) to air on the electrochemical performance. Here, MFCs enriched using an effluent from a MFC operated for about eight months. After 30 days, the condition of these systems was reversed from aerobic to anaerobic and vice versa, and their effects were observed for 11 days. The results show that for anaerobic MFCs, power generation was reduced when the anodes were exposed to dissolved oxygen of 7.5 ppm. The long exposure of anodic biofilm to air led to poor electrochemical performance. The power generation recovered fully when air supply stopped entering the anode compartment with a reduction of internal resistance up to 53 %. The study was able to show that mixed facultative microorganism able to strive through the aerobic condition for about a month at 7.5 ppm oxygen or less. The anaerobic condition was able to turn these microbes into exoelectrogen, producing considerable power in relative to their aerobic state. (author)

  2. High-loading-substrate enzymatic hydrolysis of palm plantation waste followed by unsterilized-mixed-culture fermentation for bio-ethanol production

    Science.gov (United States)

    Bardant, Teuku Beuna; Winarni, Ina; Sukmana, Hadid

    2017-01-01

    It was desired to obtain a general formula for producing bio-ethanol from any part of lignocelluloses wastes that came from palm oil industries due to its abundance. Optimum condition that obtained by using RSM for conducting high-loading-substrate enzymatic hydrolysis of palm oil empty fruit bunch was applied to palm oil trunks and then followed by unsterilized fermentation for producing bio-ethanol. From several optimized conditions investigated, the resulted ethanol concentration could reach 7.92 %v by using 36.5 %w of palm oil trunks but the results were averagely 2.46 %v lower than palm oil empty fruit bunch. The results was statistically compared and showed best correlative coefficient at 0.808 (in scale 0-1) which support the conclusion that the optimum condition for empty fruit bunch and trunks are similar. Utilization of mixed-culture yeast was investigated to produce ethanol from unsterilized hydrolysis product but the improvement wasn't significant compares to single culture yeast.

  3. Comparison of test results in the evaluation of the WSF of several jet fuels using the standardized aquatic microcosm and the mixed flask culture protocols

    International Nuclear Information System (INIS)

    Landis, W.G.; Matthews, R.A.; Markiewicz, A.J.; Matthews, G.B.

    1993-01-01

    The water soluble fraction of the turbine fuels Jet-A, JP-4 and JP-8 have been examines as stressors for two microcosm protocols, the standardized aquatic microcosm (SAM) and the mixed flask culture (MFC). The SAM is a 3 L system inoculated with standard cultures of algae, zooplankton, bacteria, protozoa. In contrast, the MFC is 1 L and is inoculated with a complex mixture of organisms derived from a natural source. Analysis of the organism counts and physical data were conducted using conventional and newly derived multivariate methods. Physical parameters, such as pH and oxygen metabolism, were often not as sensitive as species and bacterial counts. Like the SAM system, species numbers and other variables that determined clusters varied among sampling dates. Compared to the larger yet simpler system, the MFC exhibits more violent dynamics and is more likely to become catastrophically fixated, as in systems dominated by cyanobacteria. The combination of greater diversity and smaller volume may contribute to the volatile or chaotic dynamics of the MFC system

  4. The influence of inoculum composition on selected bioactive and nutritional parameters of grass pea tempeh obtained by mixed-culture fermentation with Rhizopus oligosporus and Aspergillus oryzae strains.

    Science.gov (United States)

    Starzynska-Janiszewska, A; Stodolak, B; Dulinski, R; Mickowska, B

    2012-04-01

    Tempeh is a popular Indonesian product obtained from legume seeds by solid-state fermentation with Rhizopus sp. The aim of this research was to study the effect of simultaneous mixed-culture fermentation of grass pea seeds on selected parameters of products as compared to traditional tempeh. The inoculum contained different ratios of Rhizopus oligosporus and Aspergillus oryzae spores. The simultaneous fermentation of grass pea seeds with inoculum consisting of 1.2 × 10(6) R. oligosporus and 0.6 × 10(6) A. oryzae spores (per 60 g of seeds) resulted in a product of improved quality, as compared with traditionally made tempeh (obtained after inoculation with 1.2 × 10(6) R. oligosporus spores), at the same fermentation time. This product had radical scavenging ability 70% higher than the one obtained with pure R. oligosporus culture and contained 2.23 g/kg dm of soluble phenols. The thiamin and riboflavin levels were above three (340 µg/g dm) and two (50.50 µg/g dm) folds higher than in traditionally made tempeh, respectively. The product had 65% in vitro bioavailability of proteins and 33% in vitro bioavailability of sugars. It also contained 40% less 3-N-oxalyl-L-2, 3-diaminopropionic acid (0.074 g/kg dm), as compared to traditional tempeh.

  5. Social, Cultural, and Environmental Challenges Faced by Children on Antiretroviral Therapy in Zimbabwe: a Mixed-Method Study

    Science.gov (United States)

    Macherera, Margaret; Moyo, Lindani; Ncube, Mkhanyiseli; Gumbi, Angella

    2012-01-01

    Objectives Despite the advent of antiretroviral therapy (ART), many children, particularly in the rural communities of Zimbabwe, remain vulnerable. The purpose of this study was to determine the factors and challenges facing children on antiretroviral therapy (ART) in Brunapeg area of Mangwe District, Zimbabwe. Methods A mixed-method approach involving interviewer-guided focus group discussions and piloted semi-structured questionnaires was utilized to collect data from different key population groups. The data obtained were analyzed through content coding procedures based on a set of predetermined themes of interest. Results A number of challenges emerged as barriers to the success of antiretroviral therapy for children. Primary care givers were less informed about HIV and AIDS issues for people having direct impact on the success of antiretroviral therapy in children whilst some were found to be taking the antiretroviral drugs meant for the children. It also emerged that some primary care givers were either too young or too old to care for the children while others had failed to disclose to the children why they frequently visited the Opportunistic Infections (OI) clinic. Most primary care givers were not the biological parents of the affected children. Other challenges included inadequate access to health services, inadequate food and nutrition and lack of access to clean water, good hygiene and sanitation. The lack of community support and stigma and discrimination affected their school attendance and hospital visits. All these factors contributed to non-adherence to antiretroviral drugs. Conclusions and Public Health Implications Children on ART in rural communities in Zimbabwe remain severely compromised and have unique problems that need multi-intervention strategies both at policy and programmatic levels. Effective mitigating measures must be fully established and implemented in rural communities of developing countries in the fight for universal

  6. Social, Cultural, and Environmental Challenges Faced by Children on Antiretroviral Therapy in Zimbabwe: a Mixed Method Study

    Directory of Open Access Journals (Sweden)

    Margaret Macherera, MSc

    2012-11-01

    Full Text Available Objectives:Despite the advent of antiretroviral therapy (ART, many children, particularly in the rural communities of Zimbabwe, remain vulnerable. The purpose of this study was to determine the factors and challenges facing children on antiretroviral therapy (ART in Brunapeg area of Mangwe District, Zimbabwe.Methods:A mixed-method approach involving interviewer-guided focus group discussions and piloted semi-structured questionnaires was utilized to collect data from different key population groups. The data obtained were analyzed through content coding procedures based on a set of predetermined themes of interest.Results:A number of challenges emerged as barriers to the success of antiretroviral therapy for children. Primary care givers were less informed about HIV and AIDS issues for people having direct impact on the success of antiretroviral therapy in children whilst some were found to be taking the antiretroviral drugs meant for the children. It also emerged that some primary care givers were either too young or too old to care for the children while others had failed to disclose to the children why they frequently visited the Opportunistic Infections (OI clinic. Most primary care givers were not the biological parents of the affected children. Other challenges included inadequate access to health services, inadequate food and nutrition and lack of access to clean water, good hygiene and sanitation. The lack of community support and stigma and discrimination affected their school attendance and hospital visits. All these factors contributed to non-adherence to antiretroviral drugs.Conclusions and Public Health Implications:Children on ART in rural communities in Zimbabwe remain severely compromised and have unique problems that need multi-intervention strategies both at policy and programmatic levels. Effective mitigating measures must be fully established and implemented in rural communities of developing countries in the fight for

  7. Cultivating conditions effects on kefiran production by the mixed culture of lactic acid bacteria imbedded within kefir grains.

    Science.gov (United States)

    Zajšek, Katja; Goršek, Andreja; Kolar, Mitja

    2013-08-15

    The influence of fermentation temperature, agitation rate, and additions of carbon sources, nitrogen sources, vitamins and minerals on production of kefiran by kefir grains lactic acid bacteria was studied in a series of experiments. The main aim of the work was to increase the exopolysaccharide (EPS) production where customised milk was used as fermentation medium. It was proved that the controlling of culturing conditions and the modifying of fermentation medium conditions (i.e., carbon, nitrogen, mineral sources and vitamins) can dramatically enhance the production of the EPS. The temperature and agitation rate were critical for kefiran production during the 24 h cultivation of grains; our optimised conditions being 25°C and 80 rpm, respectively. In addition, when optimising the effects of additional nutrition, it was found that 5% (w/v) lactose, 0.1% (w/v) thiamine, and 0.1% (w/v) FeCl3 led to the maximal production of EPS. The results indicate that nutrients can be utilised to improve the production of EPS and that good kefir grains growth does not appear to be a determining factor for a high production yield of EPS. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Asian couples in negotiation: a mixed-method observational study of cultural variations across five Asian regions.

    Science.gov (United States)

    Lee, Wai-Yung; Nakamura, Shin-Ichi; Chung, Moon Ja; Chun, Young Ju; Fu, Meng; Liang, Shu-Chuan; Liu, Cui-Lian

    2013-09-01

    The purpose of this study was to explore variations in how contemporary couples from five different Asian regions negotiate disagreements. Video recordings of 50 couples (10 each from Japan, Korea, Mainland China, Taiwan, and Hong Kong) discussing unresolved disagreements provided raw data for quantitative and qualitative analyses. First, teams of coders from each region used a common protocol to make quantitative ratings of content themes and interaction patterns for couples from their own region. An interregional panel of investigators then performed in-depth qualitative reviews for half of these cases, noting cultural differences not only in observed patterns of couple behavior but also in their own perceptions of these patterns. Both quantitative and qualitative analyses revealed clear regional differences on dimensions such as overt negativity, demand-withdraw interaction, and collaboration. The qualitative results also provided a richer, more nuanced view of other (e.g., gender-linked) conflict management patterns that the quantitative analyses did not capture. Inconsistencies between qualitative and quantitative data and between the qualitative observations of investigators from different regions were most pronounced for couples from Korea and Japan, whose conflict styles were subtler and less direct than those of couples from the other regions. © FPI, Inc.

  9. Growth of mono- and mixed cultures of Nannochloropsis salina and Phaeodactylum tricornutum on struvite as a nutrient source

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Ryan W. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Siccardi, Anthony J. [Texas AgriLife Research Mariculture Lab., Corpus Christi, TX (United States); Huysman, Nathan D. [Texas AgriLife Research Mariculture Lab., Corpus Christi, TX (United States); Wyatt, Nicholas B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hewson, John C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lane, Todd W. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2015-09-26

    In this paper, the suitability of crude and purified struvite (MgNH4PO4), a major precipitate in wastewater streams, was investigated for renewable replacement of conventional nitrogen and phosphate resources for cultivation of microalgae. Bovine effluent wastewater stone, the source of crude struvite, was characterized for soluble N/P, trace metals, and biochemical components and compared to the purified mineral. Cultivation trials using struvite as a major nutrient source were conducted using two microalgae production strains, Nannochloropsis salina and Phaeodactylum tricornutum, in both lab and outdoor pilot-scale raceways in a variety of seasonal conditions. Both crude and purified struvite-based media were found to result in biomass productivities at least as high as established media formulations (maximum outdoor co-culture yield ~20 ± 4 g AFDW/m2/day). Finally, analysis of nutrient uptake by the alga suggest that struvite provides increased nutrient utilization efficiency, and that crude struvite satisfies the trace metals requirement and results in increased pigment productivity for both microalgae strains.

  10. Strategies for efficiently selecting PHA producing mixed microbial cultures using complex feedstocks: Feast and famine regime and uncoupled carbon and nitrogen availabilities.

    Science.gov (United States)

    Oliveira, Catarina S S; Silva, Carlos E; Carvalho, Gilda; Reis, Maria A

    2017-07-25

    Production of polyhydroxyalkanoates (PHAs) by open mixed microbial cultures (MMCs) has been attracting increasing interest as an alternative technology to PHA production by pure cultures, due to the potential for lower costs associated with the use of open systems (eliminating the requirement for sterile conditions) and the utilisation of cheap feedstock (industrial and agricultural wastes). Such technology relies on the efficient selection of an MMC enriched in PHA-accumulating organisms. Fermented cheese whey, a protein-rich complex feedstock, has been used previously to produce PHA using the feast and famine regime for selection of PHA accumulating cultures. While this selection strategy was found efficient when operated at relatively low organic loading rate (OLR, 2g-CODL -1 d -1 ), great instability and low selection efficiency of PHA accumulating organisms were observed when higher OLR (ca. 6g-CODL -1 d -1 ) was applied. High organic loading is desirable as a means to enhance PHA productivity. In the present study, a new selection strategy was tested with the aim of improving selection for high OLR. It was based on uncoupling carbon and nitrogen supply and was implemented and compared with the conventional feast and famine strategy. For this, two selection reactors were fed with fermented cheese whey applying an OLR of ca. 8.5g-CODL -1 (with 3.8g-CODL -1 resulting from organic acids and ethanol), and operated in parallel under similar conditions, except for the timing of nitrogen supplementation. Whereas in the conventional strategy nitrogen and carbon substrates were added simultaneously at the beginning of the cycle, in the uncoupled substrates strategy, nitrogen addition was delayed to the end of the feast phase (i.e. after exogenous carbon was exhausted). The two different strategies selected different PHA-storing microbial communities, dominated by Corynebacterium and a Xantomonadaceae, respectively with the conventional and the new approaches. The new

  11. Immunoregulatory effects of human dental pulp-derived stem cells on T cells: comparison of transwell co-culture and mixed lymphocyte reaction systems.

    Science.gov (United States)

    Demircan, Pinar Cetinalp; Sariboyaci, Ayla Eker; Unal, Zehra Seda; Gacar, Gulcin; Subasi, Cansu; Karaoz, Erdal

    2011-11-01

    BACKGROUND AIMS. Studies performed using human and animal models have indicated the immunoregulatory capability of mesenchymal stromal cells in several lineages. We investigated whether human dental pulp-derived stem cells (hDP-SC) have regulatory effects on phytohemagglutinin (PHA)-activated CD3(+) T cells. We aimed to define the regulatory mechanisms associated with hDP-SC that occur in mixed lymphocyte reaction (MLR) and transwell systems with PHA-CD3(+) T cells and hDP-SC at a ratio of 1:1. METHODS. Proliferation, apoptosis and pro- and anti-inflammatory cytokines of PHA-CD3(+)T cells, the expression of Regulatory T cells (Treg) markers and some regulatory factors related to hDP-SC, were studied in Both transwell and MLR are co-cultures systems. RESULTS. Anti-proliferative and apoptotic effects of hDP-SC were determined in co-culture systems. Elevated expression levels of human leukocyte antigen (HLA)-G, hepatocyte growth factor (HGF)-β1, intracellular adhesion molecule (ICAM-1)-1, interleukin (IL)-6, IL-10, transforming growth factor (TGF)-β1, vascular adhesion molecule (VCAM)-1 and vascular endothelial growth factor (VEGF) by hDP-SC were detected in the co-culture systems. We observed decreased expression levels of pro-inflammatory cytokines [interferon (IFN)-γ, IL-2, IL-6 receptor (R), IL-12, Interleukin-17A (IL-17A), tumor necrosis factor (TNF)-α] and increased expression levels of anti-inflammatory cytokine [inducible protein (IP)-10] from PHA-CD3(+) T cells in the transwell system. Expression of Treg (CD4(+) CD25(+) Foxp3(+)) markers was significantly induced by hDP-SC in both co-culture systems. We observed apoptosis of PHA-CD3(+) T cells with 24 h using time-lapse camera photographs and active caspase labeling; it is likely that paracrine soluble factors and molecular signals secreted by hDP-SC led this apoptosis. CONCLUSIONS. We suggest that hDP-SC have potent immunoregulatory functions because of their soluble factors and cytokines via paracrine

  12. [Effects of copper on biodegradation mechanism of trichloroethylene by mixed microorganisms].

    Science.gov (United States)

    Gao, Yanhui; Zhao, Tiantao; Xing, Zhilin; He, Zhi; Zhang, Lijie; Peng, Xuya

    2016-05-25

    We isolated and enriched mixed microorganisms SWA1 from landfill cover soils supplemented with trichloroethylene (TCE). The microbial mixture could degrade TCE effectively under aerobic conditions. Then, we investigated the effect of copper ion (0 to 15 μmol/L) on TCE biodegradation. Results show that the maximum TCE degradation speed was 29.60 nmol/min with 95.75% degradation when copper ion was at 0.03 μmol/L. In addition, genes encoding key enzymes during biodegradation were analyzed by Real-time quantitative reverse transcription PCR (RT-qPCR). The relative expression abundance of pmoA gene (4.22E-03) and mmoX gene (9.30E-06) was the highest when copper ion was at 0.03 μmol/L. Finally, we also used MiSeq pyrosequencing to investigate the diversity of microbial community. Methylocystaceae that can co-metabolic degrade TCE were the dominant microorganisms; other microorganisms with the function of direct oxidation of TCE were also included in SWA1 and the microbial diversity decreased significantly along with increasing of copper ion concentration. Based on the above results, variation of copper ion concentration affected the composition of SWA1 and degradation mechanism of TCE. The degradation mechanism of TCE included co-metabolism degradation of methanotrophs and oxidation metabolism directly at copper ion of 0.03 μmol/L. When copper ion at 5 μmol/L (biodegradation was 84.75%), the degradation mechanism of TCE included direct-degradation and co-metabolism degradation of methanotrophs and microorganisms containing phenol hydroxylase. Therefore, biodegradation of TCE by microorganisms was a complicated process, the degradation mechanism included co-metabolism degradation of methanotrophs and bio-oxidation of non-methanotrophs.

  13. [System construction of early warning for ecological security at cultural and natural heritage mixed sites and its application: a case study of Wuyishan Scenery District].

    Science.gov (United States)

    You, Wei-Bin; He, Dong-Jin; Qin, De-Hua; Ji, Zhi-Rong; Wu, Li-Yun; Yu, Jian-An; Chen, Bing-Rong; Tan, Yong

    2014-05-01

    This paper proposed a new concept of ecological security for protection by a comprehensive analysis of the contents and standards of world heritage sites. A frame concept model named "Pressure-State-Control" for early warning of ecological security at world heritage mixed sites was constructed and evaluation indicators of this frame were also selected. Wuyishan Scenery District was chosen for a case study, which has been severely disturbed by natural and artificial factors. Based on the frame model of "Pressure-State-Control" and by employing extension analysis, the matter-element model was established to assess the ecological security status of this cultural and natural world heritage mixed site. The results showed that the accuracy of ecological security early warning reached 84%. Early warning rank was I level (no alert status) in 1997 and 2009, but that in 2009 had a higher possibility to convert into II level. Likewise, the early-warning indices of sensitive ranks were different between 1997 and 2009. Population density, population growth rate, area index for tea garden, cultivated land owned per capita, level of drought, and investment for ecological and environmental construction were the main limiting factors to hinder the development of ecological security from 2009 to future. In general, the status of Wuyishan Scenery District ecological security was relatively good and considered as no alert level, while risk conditions also existed in terms of a few early-warning indicators. We still need to pay more attention to serious alert indicators and adopt effective prevention and control measures to maintain a good ecological security status of this heritage site.

  14. Biomass production and biological depuration of sugar cane vinasse by mixed culture of filamentous fungi and yeasts; Producao de biomassa e depuracao biologica da vinhaca de cana-de-acucar por cultura mista de fungos filamentosos e leveduras

    Energy Technology Data Exchange (ETDEWEB)

    Ceccato, Sandra Regina

    1988-12-01

    Sugar and alcohol technology has originated wastes such as vinasse with organic load that causes pollution in Brazil. Many alternatives have been proposed to convert it into useful products such as microbial protein. The aim of this work was to select mixed cultures of filamentous fungi and yeasts with high biomass production in vinasse and to study the cultural condition optimization of the selected combination based on the protein content and the waste depuration. The growth of pure cultures along the time was also evaluated as well as the amino acid composition of the biomass obtained. (author)

  15. Acute toxicity of heavy metals to acetate-utilizing mixed cultures of sulfate-reducing bacteria: EC100 and EC50.

    Science.gov (United States)

    Utgikar, V P; Chen, B Y; Chaudhary, N; Tabak, H H; Haines, J R; Govind, R

    2001-12-01

    Acid mine drainage from abandoned mines and acid mine pit lakes is an important environmental concern and usually contains appreciable concentrations of heavy metals. Because sulfate-reducing bacteria (SRB) are involved in the treatment of acid mine drainage, knowledge of acute metal toxicity levels for SRB is essential for the proper functioning of the treatment system for acid mine drainage. Quantification of heavy metal toxicity to mixed cultures of SRB is complicated by the confounding effects of metal hydroxide and sulfide precipitation, biosorption, and complexation with the constituents of the reaction matrix. The objective of this paper was to demonstrate that measurements of dissolved metal concentrations could be used to determine the toxicity parameters for mixed cultures of sulfate-reducing bacteria. The effective concentration, 100% (EC100), the lowest initial dissolved metal concentrations at which no sulfate reduction is observed, and the effective concentration, 50% (EC50), the initial dissolved metal concentrations resulting in a 50% decrease in sulfate reduction, for copper and zinc were determined in the present study by means of nondestructive, rapid physical and chemical analytical techniques. The reaction medium used in the experiments was designed specifically (in terms of pH and chemical composition) to provide the nutrients necessary for the sulfidogenic activity of the SRB and to preclude chemical precipitation of the metals under investigation. The toxicity-mitigating effects of biosorption of dissolved metals were also quantified. Anaerobic Hungate tubes were set up (at least in triplicate) and monitored for sulfate-reduction activity. The onset of SRB activity was detected by the blackening of the reaction mixture because of formation of insoluble ferrous sulfide. The EC100 values were found to be 12 mg/L for copper and 20 mg/L for zinc. The dissolved metal concentration measurements were effective as the indicators of the effect of the

  16. Cell-to-cell contact and antimicrobial peptides play a combined role in the death of Lachanchea thermotolerans during mixed-culture alcoholic fermentation with Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Kemsawasd, Varongsiri; Branco, Patrícia; Almeida, Maria Gabriela

    2015-01-01

    The roles of cell-to-cell contact and antimicrobial peptides in the early death of Lachanchea thermotolerans CBS2803 during anaerobic, mixed-culture fermentations with Saccharomyces cerevisiae S101 were investigated using a commercially available, double-compartment fermentation system separated ...

  17. Cultura lática mista com potencial de aplicação como cultura iniciadora em produtos cárneos Mixed lactic culture with potential application as starter culture in meat products

    Directory of Open Access Journals (Sweden)

    Rosicler BALDUINO

    1999-12-01

    . They can be formed by pure or mixed culture that are able to produce antimicrobial substances as lactic acid and bacteriocins and to inhibit undesirable microorganisms in the food product. In this work there were evaluated various associations of lactic bacteria among Lactobacillus, Pediococcus and Enterococcus, in order to obtain lactic cultures with the biochemical ability for homolactic fermentation; high cellular viability; tolerance to the NaCl and NaNO2 salts; able to reduce nitrites and to inhibit pathogens such as S. aureus, Salmonella and E. coli. The cultures were developed in MRS medium, incubated at 37ºC for 48 hours. Lactic acid was determined by HPLC. Residual nitrite was measured by spectrophotometry. The homolactic fermentation with better lactic acid production (4.61% and higher cellular viability (3x10(15 CFU/mL were obtained by the culture constituted by L. curvatus, L. plantarum, P. acidilactici e E. faecium. The selected starter showed high cellular viability (1x10(14CFU/mL, even in high concentrations of NaCl and NaNO2. The fermented broth showed reduction (99% of initial nitrite. The selected mixed lactic acid culture inhibited S. aureus, Salmonella spp. and E. coli in BHI-agar. In fresh sausage it was observed reductions on counts of S. aureus and total coliforms were observed in fresh sausage, in relation to the controls. Salmonella spp. was not detected in the assayed samples. The results show the possibility of application of the selected mixed culture as starter culture in meat products.

  18. Column study of enhanced Cr(VI) removal and longevity by coupled abiotic and biotic processes using Fe0 and mixed anaerobic culture.

    Science.gov (United States)

    Zhong, Jiawei; Yin, Weizhao; Li, Yongtao; Li, Ping; Wu, Jinhua; Jiang, Gangbiao; Gu, Jingjing; Liang, Hao

    2017-10-01

    In this study, Fe 0 and mixed anaerobic culture were integrated in one column to investigate the coupled abiotic and biotic effects on hexa-valent chromium (Cr(VI)) removal and column longevity with an abiotic Fe 0 column in the control experiments. According to the breakthrough study, a slower Cr(VI) breakthrough rate of 0.19 cm/PV was observed in the biotic Fe 0 column whereas the value in the abiotic Fe 0 column was 0.30 cm/PV, resulting in 64% longer life-span and 62% higher Cr(VI) removal capacity in the biotic Fe 0 column than the abiotic one. The solid phase characterization by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) confirmed that this enhancement was attributed to the higher consumption of iron and greater production of diverse reactive minerals (e.g., green rust, magnetite and lepidocrocite) induced by the synergistic interaction of Fe 0 and anaerobic culture, providing more reactive sites for Cr(VI) adsorption, reduction and co-precipitation. Furthermore, the decreasing breakthrough rates and growing iron corrosion along the biotic Fe 0 column demonstrated an inhomogeneous distribution of reactive zones in the column and its latter 3/5 section was considered to be the most reactive area for Cr(VI) removal. These results indicate that the inoculation of microorganisms in Fe 0 -based permeable reactive barriers will enable this technology a higher removal capacity and longer life-span for the remediation of Cr(VI)-contaminated groundwater. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Effects of disciplinary cultures of researchers and research trainees on the acceptability of nanocarriers for drug delivery in different contexts of use: a mixed-methods study

    International Nuclear Information System (INIS)

    Chenel, Vanessa; Boissy, Patrick; Cloarec, Jean-Pierre; Patenaude, Johane

    2015-01-01

    The acceptability of nanomedical applications, which have the potential to generate ethical and societal impacts, is a significant factor in the deployment of nanomedicine. A lack of fit between nanomedical applications and society’s values may result from a partial consideration of such impacts. New approaches for technological evaluation focused on impact perception, acceptance, and acceptability are needed to go beyond traditional technology assessment approaches used with nanotechnology, which focus mainly on toxicological and safety criteria. Using a new evaluative approach based on perceived impacts of nanotechnology, the objective of this study was to assess perceptions among researchers and research trainees familiar with emergent technologies and from different disciplinary background the scope of acceptability judgments made towards the use of nanocarriers. This mixed-methods study was based on scenarios presenting two types of drug-delivery nanocarriers (carbon, synthetic DNA) in two contexts of use (lung cancer treatment, seasonal flu treatment). Researchers and research trainees in the natural sciences and engineering, and the social sciences and the humanities were invited by email to take part in this project. An online questionnaire followed by semi-directed interviews allowed characterization of disciplinary divergences regarding to impact perception, acceptance, and acceptability of the scenarios. The results suggest that impact perception is influenced by disciplinary culture. Also, trends can be seen between respondents’ profiles and variables of acceptance and acceptability, and certain components of the acceptability judgement are specific to each disciplinary culture. The acknowledgment and consideration of these disciplinary divergences could allow, among others, for opening up interdisciplinary dialogue on matters related to the acceptability of nanomedical applications and their developments

  20. Microbial bio-based plastics from olive-mill wastewater: Generation and properties of polyhydroxyalkanoates from mixed cultures in a two-stage pilot scale system.

    Science.gov (United States)

    Ntaikou, I; Valencia Peroni, C; Kourmentza, C; Ilieva, V I; Morelli, A; Chiellini, E; Lyberatos, G

    2014-10-20

    The operational efficiency of a two stage pilot scale system for polyhydroxyalkanoates (PHAs) production from three phase olive oil mill wastewater (OMW) was investigated in this study. A mixed anaerobic, acidogenic culture derived from a municipal wastewater treatment plant, was used in the first stage, aiming to the acidification of OMW. The effluent of the first bioreactor that was operated in continuous mode, was collected in a sedimentation tank in which partial removal of the suspended solids was taking place, and was then forwarded to an aerobic reactor, operated in sequential batch mode under nutrient limitation. In the second stage an enriched culture of Pseudomonas sp. was used as initial inoculum for the production of PHAs from the acidified waste. Clarification of the acidified waste, using aluminium sulphate which causes flocculation and precipitation of solids, was also performed, and its effect on the composition of the acidified waste as well as on the yields and properties of PHAs was investigated. It was shown that clarification had no significant qualitative or quantitative effect on the primary carbon sources, i.e. short chain fatty acids and residual sugars, but only on the values of total suspended solids and total chemical oxygen demand of the acidified waste. The type and thermal characteristics of the produced PHAs were also similar for both types of feed. However the clarification of the waste seemed to have a positive impact on final PHAs yield, measured as gPHAs/100g of VSS, which reached up to 25%. Analysis of the final products via nuclear magnetic resonance spectroscopy revealed the existence of 3-hydroxybutyrate (3HB) and 3-hydroxyoctanoate (HO) units, leading to the conclusion that the polymer could be either a blend of P3HB and P3HO homopolymers or/and the 3HB-co-3HO co-polymer, an unusual polymer occurring in nature with advanced properties. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Effects of disciplinary cultures of researchers and research trainees on the acceptability of nanocarriers for drug delivery in different contexts of use: a mixed-methods study

    Energy Technology Data Exchange (ETDEWEB)

    Chenel, Vanessa; Boissy, Patrick, E-mail: patrick.boissy@usherbrooke.ca [Université de Sherbrooke, Interdisciplinary Institute for Technological Innovation (3IT) (Canada); Cloarec, Jean-Pierre [Université de Sherbrooke, Laboratoire Nanotechnologies et Nanosystèmes (LN2), Centre National de la Recherche Scientifique (CNRS) (Canada); Patenaude, Johane [Université de Sherbrooke, Interdisciplinary Institute for Technological Innovation (3IT) (Canada)

    2015-04-15

    The acceptability of nanomedical applications, which have the potential to generate ethical and societal impacts, is a significant factor in the deployment of nanomedicine. A lack of fit between nanomedical applications and society’s values may result from a partial consideration of such impacts. New approaches for technological evaluation focused on impact perception, acceptance, and acceptability are needed to go beyond traditional technology assessment approaches used with nanotechnology, which focus mainly on toxicological and safety criteria. Using a new evaluative approach based on perceived impacts of nanotechnology, the objective of this study was to assess perceptions among researchers and research trainees familiar with emergent technologies and from different disciplinary background the scope of acceptability judgments made towards the use of nanocarriers. This mixed-methods study was based on scenarios presenting two types of drug-delivery nanocarriers (carbon, synthetic DNA) in two contexts of use (lung cancer treatment, seasonal flu treatment). Researchers and research trainees in the natural sciences and engineering, and the social sciences and the humanities were invited by email to take part in this project. An online questionnaire followed by semi-directed interviews allowed characterization of disciplinary divergences regarding to impact perception, acceptance, and acceptability of the scenarios. The results suggest that impact perception is influenced by disciplinary culture. Also, trends can be seen between respondents’ profiles and variables of acceptance and acceptability, and certain components of the acceptability judgement are specific to each disciplinary culture. The acknowledgment and consideration of these disciplinary divergences could allow, among others, for opening up interdisciplinary dialogue on matters related to the acceptability of nanomedical applications and their developments.

  2. Effect of Feeding a Mixed Microbial Culture Fortified with Trace Minerals on the Performance and Carcass Characteristics of Late-fattening Hanwoo Steers: A Field Study

    Directory of Open Access Journals (Sweden)

    W. S. Kwak

    2015-11-01

    Full Text Available This study was conducted to determine the effects of feeding a trace minerals-fortified microbial culture (TMC on the performance and carcass characteristics of late-fattening Hanwoo steers. A mixture of microbes (0.6% [v/w] of Enterobacter sp., Bacillus sp., Lactobacillus sp., and Saccharomyces sp. was cultured with 99% feedstuff for ensiling and 0.4% trace minerals (zinc, selenium, copper, and cobalt. Sixteen late-fattening steers (mean age, 21.8 months were allocated to two diets: a control diet (concentrate mix and rice straw and a treated diet (control diet+3.3% TMC. At a mean age of 31.1 months, all the steers were slaughtered. The addition of TMC to the diet did not affect the average daily weight gain of the late fattening steers, compared with that of control steers. Moreover, consuming the TMC-supplemented diet did not affect cold carcass weight, yield traits such as back fat thickness, longissimus muscle area, yield index or yield grade, or quality traits such as meat color, fat color, texture, maturity, marbling score, or quality grade. However, consumption of a TMC-supplemented diet increased the concentrations of zinc, selenium, and sulfur (p<0.05 in the longissimus muscle. With respect to amino acids, animals consuming TMC showed increased (p<0.05 concentrations of lysine, leucine, and valine among essential amino acids and a decreased (p<0.05 concentration of proline among non-essential amino acids. In conclusion, the consumption of a TMC-supplemented diet during the late-fattening period elevated the concentrations of certain trace minerals and essential amino acids in the longissimus muscle, without any deleterious effects on performance and other carcass characteristics of Hanwoo steers.

  3. Enhanced acetic acid production from manalagi apple (Malus sylvestris mill) by mixed cultures of Saccharomyces cerevisiae and Acetobacter aceti in submerged fermentation

    Science.gov (United States)

    Rosada, K. K.

    2018-05-01

    The production of acetic acid from Manalagi apple was studied using a mixed culture of S. cerevisiae and A. aceti by submerged fermentation technique. Determination of the best conditions for producing acetic acid was performed by stratified optimization with variations that were made on the concentration of the initial sugar addition to the medium (0%, 10%, 20% w/v), the ratio of the number of inocula S. cerevisiae and A. aceti (7:3, 1:1, 3:7), and agitation rate (80 and 160 rpm). All experiments were done by using the initial pH medium of 4.5 and incubated at room temperature (28±2oC) for 14 days. The concentration of reducing sugar, alcohol, acetic acid, and the pH were measured every 48 hours. The efficiency of sugar conversion to acetic acid with the addition of initial sugar 0%, 10%, and20%were 233%, 46.6%, and 6.4% respectively after ten days of incubation. Overall, the result showed that the highest acetic acid was produced from Manalagi apple juice when no sugar was added, using seven parts of S. cerevisiae to three parts of A. aceti and agitation rate of 160 rpm on the tenth day of fermentation. Under these conditions, glucose conversion efficiency to acetic acid increased to 362%.

  4. Application of a mixed culture of adapted acidophilic bacteria in two-step bioleaching of spent lithium-ion laptop batteries

    Science.gov (United States)

    Heydarian, Ahmad; Mousavi, Seyyed Mohammad; Vakilchap, Farzane; Baniasadi, Mahsa

    2018-02-01

    The rapid increase in the production of electrical and electronic equipment, along with higher consumption of these products, has caused defective and obsolete equipment to accumulate in the environment. In this research, bioleaching of spent lithium-ion batteries (LIBs) used in laptops is carried out under two-step condition based on the bacterial activities of a mixture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. First, the best inoculum ratio of two acidophilic bacteria for the mixed culture is obtained. Next, adaptation is carried out successfully and the solid-to-liquid ratio reaches 40 g L-1. Response surface methodology is utilized to optimize the effective variables of initial pH, iron sulfate and sulfur concentrations. The maximum recovery of metal is about 99.2% for Li, 50.4% for Co and 89.4% for Ni under optimum conditions of 36.7 g L-1 iron sulfate concentration, 5.0 g L-1 sulfur concentration and initial pH of 1.5 for the best inoculum ratio of 3/2. Results of FE-SEM, XRD and FTIR analysis before and after bioleaching confirm that bacterial activity is a promising and effective route for metal recovery from spent LIBs. Toxicity assessment tests demonstrate the suitability of the bioleached residual as a nonhazardous material that meets environmental limitations for safe disposal.

  5. Study of cultivation and growth rate kinetic for mixed cultures of local microalgae as third generation (G-3) bioethanol feedstock in thin layer photobioreactor

    Science.gov (United States)

    Prihastuti Yuarrina, Wahyu; Surya Pradana, Yano; Budiman, Arief; Majid, Akmal Irfan; Indarto; Agus Suyono, Eko

    2018-05-01

    The increasing use of fossil fuels causes the depletion in supply and contributes to climate change by GHG emissions into the atmosphere. Microalgae indicate as renewable and sustainable energy sources as they have a high potential for producing large amounts of biomass for third-generation biofuels (bioethanol and biodiesel) feedstock. However, there are several parameters which should be considered for microalgae cultivation, such as environmental conditions, medium composition and microalgae species. The aim of this research was to study cultivation of mixed microalgae cultures (Glagah consortium and Arthrospira maxima) in a thin layer photobioreactor. Farmpion medium, Bold’s Basal Medium (BBM) and Thoriq Eko Arief (TEA) medium were investigated as cultivation medium for bioethanol feedstock for 7 days. The results showed that the highest dry weight concentration of microalgae was in Farmpion medium (0.35 mg/ml) and the highest carbohydrate concentration of microalgae was in BBM (0.14 mg/ml). Thus, the optimum medium of microalgae cultivation for bioethanol feedstock was BBM because of the highest carbohydrate-dry weight ratio (0.88). In addition, mathematical approach by using Contois model was used to find out the growth rate of microalgae cultivation in each medium.

  6. Effects of carbon sources on the enrichment of halophilic polyhydroxyalkanoate-storing mixed microbial culture in an aerobic dynamic feeding process

    Science.gov (United States)

    Cui, You-Wei; Zhang, Hong-Yu; Lu, Peng-Fei; Peng, Yong-Zhen

    2016-08-01

    Microbial polyhydroxyalkanoate (PHA) production serves as a substitute for petroleum-based plastics. Enriching mixed microbial cultures (MMCs) with the capacity to store PHA is a key precursor for low-cost PHA production. This study investigated the impact of carbon types on enrichment outcomes. Three MMCs were separately fed by acetate sodium, glucose, and starch as an enriching carbon source, and were exposed to long-term aerobic dynamic feeding (ADF) periods. The PHA production capacity, kinetics and stoichiometry of the enrichments, the PHA composition, and the microbial diversity and community composition were explored to determine carbon and enrichment correlations. After 350-cycle enriching periods under feast-famine (F-F) regimes, the MMCs enriched by acetate sodium and glucose contained a maximum PHA content of 64.7% and 60.5% cell dry weight (CDW). The starch-enriched MMC only had 27.3% CDW of PHA. High-throughput sequencing revealed that non-PHA bacteria survived alongside PHA storing bacteria, even under severe F-F selective pressure. Genus of Pseudomonas and Stappia were the possible PHA accumulating bacteria in acetate-enriched MMC. Genus of Oceanicella, Piscicoccus and Vibrio were found as PHA accumulating bacteria in glucose-enriched MMC. Vibrio genus was the only PHA accumulating bacteria in starch-enriched MMC. The community diversity and composition were regulated by the substrate types.

  7. Biohydrogen production from pig slurry in a CSTR reactor system with mixed cultures under hyper-thermophilic temperature (70 oC)

    International Nuclear Information System (INIS)

    Kotsopoulos, Thomas A.; Fotidis, Ioannis A.; Tsolakis, Nikolaos; Martzopoulos, Gerassimos G.

    2009-01-01

    A continuous stirred tank reactor (CSTR) (750 cm 3 working volume) was operated with pig slurry under hyper-thermophilic (70 o C) temperature for hydrogen production. The hydraulic retention time (HRT) was 24 h and the organic loading rate was 24.9 g d -1 of volatile solid (VS). The inoculum used in the hyper-thermophilic reactor was sludge obtained from a mesophilic methanogenic reactor. The continuous feeding with active biomass (inoculum) from the mesophilic methanogenic reactor was necessary in order to achieve hydrogen production. The hyper-thermophilic reactor started to produce hydrogen after a short adapted period of 4 days. During the steady state period the mean hydrogen yield was 3.65 cm 3 g -1 of volatile solid added. The high operation temperature of the reactor enhanced the hydrolytic activity in pig slurry and increased the volatile fatty acids (VFA) production. The short HRT (24 h) and the hyper-thermophilic temperature applied in the reactor were enough to prevent methanogenesis. No pre-treatment methods or other control methods for preventing methanogenesis were necessary. Hyper-thermophilic hydrogen production was demonstrated for the first time in a CSTR system, fed with pig slurry, using mixed culture. The results indicate that this system is a promising one for biohydrogen production from pig slurry.

  8. Hydraulic retention time affects stable acetate production from tofu processing wastewater in extreme-thermophilic (70°C) mixed culture fermentation.

    Science.gov (United States)

    Chen, Yun; Zhang, Fang; Wang, Ting; Shen, Nan; Yu, Zhong-Wei; Zeng, Raymond J

    2016-09-01

    Acetate is an important industrial chemical and its production from wastes via mixed culture fermentation (MCF) is economic. In this work, the effect of hydraulic retention time (HRT) on acetate production from tofu processing wastewater (TPW) in extreme-thermophilic (70°C) MCF was first investigated. It was found that long HRT (>3days) could lead to less acetate production while stable acetate production was achieved at short HRT (3days) with the yield of 0.57g-COD/g-CODTPW. The microbial community analysis showed that hydrogenotrophic methanogens (mainly Methanothermobacter) occupied up to 90% of archaea at both HRTs of 3 and 5days. However, Coprothermobacter, the main acetate-degraders, decreased from 35.74% to 10.58% of bacteria when HRT decreased from 5 to 3days, supporting the aggravation of syntrophic acetate oxidation in long HRT. This work demonstrated that HRT was a crucial factor to maintain stable acetate production from TPW in extreme-thermophilic MCF. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Comparison of dairy desserts produced with a potentially probiotic mixed culture and dispersions obtained from Gracilaria birdiae and Gracilaria domingensis seaweeds used as thickening agents.

    Science.gov (United States)

    Tavares Estevam, Adriana Carneiro; de Almeida, Michele Correia; de Oliveira, Tiago Almeida; Florentino, Eliane Rolim; Alonso Buriti, Flávia Carolina; Porto, Ana Lúcia Figueiredo

    2017-09-20

    Dairy desserts have emerged as interesting options for the incorporation of probiotics, bioactive ingredients and alternative sources of thickeners. This shows an opportunity to investigate the use of Gracilaria seaweeds in the formulation of potentially probiotic dairy desserts. This study aimed to compare the effects of dispersions obtained from Gracilaria domingensis and Gracilaria birdiae used as thickening agents on texture properties of dairy desserts fermented with SAB 440-A, composed of the starter Streptococcus thermophilus and the potential probiotics Bifidobacterium animalis and Lactobacillus acidophilus, and also to study their physicochemical characteristics, microbial viability and sensory acceptability. No significant differences between desserts with G. birdiae or G. domingensis dispersions regarding total solids, ash and fat content, as well as pH, titratable acidity, the viability of the microorganisms of the mixed culture and sensory acceptability were verified (P > 0.05). Nonetheless, the dessert with G. domingensis dispersion showed higher dietary fibre content and significantly increased firmness than the one produced with G. birdiae (P desserts, in the presence of either G. birdiae or G. domingensis dispersions, despite the fact that L. acidophilus has shown low viability in the final products. Therefore, the G. domingensis dispersion is suitable to be used as a thickening agent to produce dairy desserts with enhanced firmness and good sensory acceptability, it being also advisable to use only B. animalis as a probiotic for this product.

  10. Investigation of the bacteriophage community in induced lysates of undefined mesophilic mixed-strain DL-cultures using classical and metagenomic approaches.

    Science.gov (United States)

    Muhammed, Musemma K; Olsen, Mette L; Kot, Witold; Neve, Horst; Castro-Mejía, Josué L; Janzen, Thomas; Hansen, Lars H; Nielsen, Dennis S; Sørensen, Søren J; Heller, Knut J; Vogensen, Finn K

    2018-05-02

    To investigate the notion that starter cultures can be a reservoir of bacteriophages (phages) in the dairy environment, strains of three DL-starters (undefined mesophilic mixed-strain starters containing Lactococcus lactis subsp. lactis biovar. diacetylactis and Leuconostoc species) were selected and induced by mitomycin C, and the whole starters were induced spontaneously as well as by mitomycin C. Frequency of induction of 17%, 26% and 12% was estimated among the isolates of the three starters, with majority of the induced phages mostly showing morphological similarity to known P335 phages, and with a fraction of them showing atypical features. Sequences of P335 quasi-species phages were found to be the most frequent entities in almost all metaviromes derived from the induced lysates. However, sequences of Sk1virus phages (previously 936 phages) were emerged as the predominant entities following spontaneous induction of one of the starters, suggesting a phage-carrier state. Sequences of other phages such as 949, 1706, C2virus (previously c2 phages) and Leuconostoc species could also be observed but with a lower relative frequency. Taken together, the majority of the P335 quasi-species phages could represent the induced viral community of the starters and the remaining phage groups mainly represent the background ambient viral community. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Comparison of Different Strategies for Selection/Adaptation of Mixed Microbial Cultures Able to Ferment Crude Glycerol Derived from Second-Generation Biodiesel

    Directory of Open Access Journals (Sweden)

    C. Varrone

    2015-01-01

    Full Text Available Objective of this study was the selection and adaptation of mixed microbial cultures (MMCs, able to ferment crude glycerol generated from animal fat-based biodiesel and produce building-blocks and green chemicals. Various adaptation strategies have been investigated for the enrichment of suitable and stable MMC, trying to overcome inhibition problems and enhance substrate degradation efficiency, as well as generation of soluble fermentation products. Repeated transfers in small batches and fed-batch conditions have been applied, comparing the use of different inoculum, growth media, and Kinetic Control. The adaptation of activated sludge inoculum was performed successfully and continued unhindered for several months. The best results showed a substrate degradation efficiency of almost 100% (about 10 g/L glycerol in 21 h and different dominant metabolic products were obtained, depending on the selection strategy (mainly 1,3-propanediol, ethanol, or butyrate. On the other hand, anaerobic sludge exhibited inactivation after a few transfers. To circumvent this problem, fed-batch mode was used as an alternative adaptation strategy, which led to effective substrate degradation and high 1,3-propanediol and butyrate production. Changes in microbial composition were monitored by means of Next Generation Sequencing, revealing a dominance of glycerol consuming species, such as Clostridium, Klebsiella, and Escherichia.

  12. Comparison of Different Strategies for Selection/Adaptation of Mixed Microbial Cultures Able to Ferment Crude Glycerol Derived from Second-Generation Biodiesel.

    Science.gov (United States)

    Varrone, C; Heggeset, T M B; Le, S B; Haugen, T; Markussen, S; Skiadas, I V; Gavala, H N

    2015-01-01

    Objective of this study was the selection and adaptation of mixed microbial cultures (MMCs), able to ferment crude glycerol generated from animal fat-based biodiesel and produce building-blocks and green chemicals. Various adaptation strategies have been investigated for the enrichment of suitable and stable MMC, trying to overcome inhibition problems and enhance substrate degradation efficiency, as well as generation of soluble fermentation products. Repeated transfers in small batches and fed-batch conditions have been applied, comparing the use of different inoculum, growth media, and Kinetic Control. The adaptation of activated sludge inoculum was performed successfully and continued unhindered for several months. The best results showed a substrate degradation efficiency of almost 100% (about 10 g/L glycerol in 21 h) and different dominant metabolic products were obtained, depending on the selection strategy (mainly 1,3-propanediol, ethanol, or butyrate). On the other hand, anaerobic sludge exhibited inactivation after a few transfers. To circumvent this problem, fed-batch mode was used as an alternative adaptation strategy, which led to effective substrate degradation and high 1,3-propanediol and butyrate production. Changes in microbial composition were monitored by means of Next Generation Sequencing, revealing a dominance of glycerol consuming species, such as Clostridium, Klebsiella, and Escherichia.

  13. Characteristics of mixed culture where one type of microorganism assimilates the metabolite; Isshurui no biseibutsu ga seiseisuru taishabutsu wo betsuno shuruino biseibutsu ga shikashite zoshokusuru kongo baiyo no moderuka to tokusei kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Toyama, M.; Matsunaka, T.; Shimizu, K. [Kyushu Inst. of Tech., Fukuoka (Japan). Dept. of Biochemical Engineering and Science

    2000-11-10

    Unstructure models were developed for a mixed culture where one microorganism assimilates the metabolite produced by another microorganism The model system was a mixed culture using Lactobacillus delbrueckii and Ralstonia erthroprop where the former assimilates glucose and produces lactic acid, and the latter assimilates lactate and produce poly {beta}-hydroxy butyrate (PHB). Performance improvement is shown for the mixed culture over a single culture for chemostat using the model developed. Since the optimal dissolved oxygen (DO) concentration is different for each microorganism, we developed another model which takes into account the effect of DO concentration on the dynamic behavior. Then the optimal DO concentration is obtained for chemostat. Moreover, we developed another model which takes into account NH{sub 3} concentration on the cell grown and PHB production by R. eutropha. Then the optimal time-profile for NH{sub 3} concentration is derived using the maximum principle. It is found that high Phba production could be attained even if NH{sub 3} concentration is not controlled if initial NH{sub 3} concentration is appropriately selected. (author)

  14. Regulation of primary cytotoxic T lymphocyte responses generated during mixed leukocyte culture with H-2d identical Qa-1-disparate cells

    International Nuclear Information System (INIS)

    Huston, D.P.; Tavana, G.; Rich, R.R.; Gressens, S.E.

    1986-01-01

    Cytotoxic lymphocyte (CTL) responses are not usually generated during primary mixed leukocyte culture (MLC) with H-2 identical cells. Thus NZB mice are unusual in that their spleen cells do mount CTL responses during primary MLC with H-2d identical stimulator cells; the predominant target antigen for these NZB responses is Qa-1b. Considering the numerous immunoregulatory defects in NZB mice, we postulated that these NZB anti-Qa-1 primary CTL responses were due to an abnormality in T suppressor cell activity. Cellular interactions capable of suppressing NZB anti-Qa-1 primary CTL responses were investigated by using one-way and two-way MLC with spleen cells from NZB mice and other H-2d strains. Although H-2d identical one-way MLC with the use of NZB responders resulted in substantial CTL responses, only minimal CTL responses were detected from two-way MLC with the use of NZB spleen cells plus nonirradiated spleen cells from other H-2d mice. Thus the presence of non-NZB spleen cells in the two-way H-2d identical MLC prevented the generation of NZB CTL. Noncytotoxic mechanisms were implicated in the suppression of the NZB CTL responses during two-way MLC, because only minimal CTL activity was generated when NZB spleen cells were cultured with semiallogeneic, H-2d identical (e.g., NZB X BALB) F1 spleen cells. The observed suppression could be abrogated with as little as 100 rad gamma-irradiation to the non-NZB spleen cells. The phenotype of these highly radiosensitive spleen cells was Thy-1+, Lyt-1+, Lyt-2-, L3T4+. The functional presence of these cells in the spleens of semiallogeneic, H-2d identical F1 mice indicated that their deficiency in NZB mice was a recessive trait. These data suggest that NZB mice lack an L3T4+ cell present in the spleens of normal mice that is capable of suppressing primary anti-Qa-1 CTL responses

  15. Simultaneous biohydrogen production and starch wastewater treatment in an acidogenic expanded granular sludge bed reactor by mixed culture for long-term operation

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Wan-Qian; Ren, Nan-Qi; Liu, Bing-Feng; Ding, Jie [State Key Lab of Urban Water Resource and Environ, Harbin Institute of Technology, Harbin 150090 (China); Chen, Zhao-Bo [School of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Wang, Xiang-Jing; Xiang, Wen-Sheng [Research Center of Life Science and Biotechnology, Northeast Agricultural University, Harbin 150030 (China)

    2008-12-15

    The biofilm-based expanded granular sludge bed (EGSB) reactor was developed to treat starch-containing wastewater and simultaneously recovery hydrogen by mixed microbial culture. Granular activated carbon (GAC) was used as the support media. Operating at the temperature of 30 C for over 400 days (data not shown), the EGSB reactor presented high efficiency in hydrogen production and COD removal ability. The maximum hydrogen production rate (HPR) was found to be 1.64 L/L.d under the organic loading rate (OLR) of 1.0 g-starch/L.d, pH of 4.42 and HRT of 4 h. The hydrogen yield (HY) peaked at 0.11 L/g-COD, under the OLR of 0.5 g-starch/L.d, pH of 3.95 and HRT of 8 h. Hydrogen volume content was estimated to be 35-65% of the total biogas. The average COD removal rate was 31.1% under the OLR of 0.125 g-starch/L.d and HRT of 24 h. The main dissolved fermentation products were ethanol, acetate and butyrate. The average attached biofilm concentration was estimated to be 8.26 g/L, which favored hydrogen production and COD removal. It is speculated that the low pH operation in the present system would contribute significantly to lower the cost of alkaline amount required for pH control in the continuous operation, especially in the scale-up biohydrogen producing system. A model, built on the back propagation neural network (BPNN) theory and linear regression techniques, was developed for the simulation of EGSB system performance in the biodegradation of starch synthesis-based wastewater and simultaneous hydrogen production. The model well fitted the laboratory data, and could well simulate the removal of COD and the production of hydrogen in the EGSB reactor. (author)

  16. Methane-Fueled Syntrophy through Extracellular Electron Transfer: Uncovering the Genomic Traits Conserved within Diverse Bacterial Partners of Anaerobic Methanotrophic Archaea.

    Science.gov (United States)

    Skennerton, Connor T; Chourey, Karuna; Iyer, Ramsunder; Hettich, Robert L; Tyson, Gene W; Orphan, Victoria J

    2017-08-01

    The anaerobic oxidation of methane by anaerobic methanotrophic (ANME) archaea in syntrophic partnership with deltaproteobacterial sulfate-reducing bacteria (SRB) is the primary mechanism for methane removal in ocean sediments. The mechanism of their syntrophy has been the subject of much research as traditional intermediate compounds, such as hydrogen and formate, failed to decouple the partners. Recent findings have indicated the potential for extracellular electron transfer from ANME archaea to SRB, though it is unclear how extracellular electrons are integrated into the metabolism of the SRB partner. We used metagenomics to reconstruct eight genomes from the globally distributed SEEP-SRB1 clade of ANME partner bacteria to determine what genomic features are required for syntrophy. The SEEP-SRB1 genomes contain large multiheme cytochromes that were not found in previously described free-living SRB and also lack periplasmic hydrogenases that may prevent an independent lifestyle without an extracellular source of electrons from ANME archaea. Metaproteomics revealed the expression of these cytochromes at in situ methane seep sediments from three sites along the Pacific coast of the United States. Phylogenetic analysis showed that these cytochromes appear to have been horizontally transferred from metal-respiring members of the Deltaproteobacteria such as Geobacter and may allow these syntrophic SRB to accept extracellular electrons in place of other chemical/organic electron donors. IMPORTANCE Some archaea, known as anaerobic methanotrophs, are capable of converting methane into carbon dioxide when they are growing syntopically with sulfate-reducing bacteria. This partnership is the primary mechanism for methane removal in ocean sediments; however, there is still much to learn about how this syntrophy works. Previous studies have failed to identify the metabolic intermediate, such as hydrogen or formate, that is passed between partners. However, recent analysis of

  17. Methylovulum psychrotolerans sp. nov., a cold-adapted methanotroph from low-temperature terrestrial environments, and emended description of the genus Methylovulum.

    Science.gov (United States)

    Oshkin, Igor Y; Belova, Svetlana E; Danilova, Olga V; Miroshnikov, Kirill K; Rijpstra, W Irene C; Sinninghe Damsté, Jaap S; Liesack, Werner; Dedysh, Svetlana N

    2016-06-01

    Two isolates of aerobic methanotrophic bacteria, strains Sph1T and Sph2, were obtained from cold methane seeps in a floodplain of the river Mukhrinskaya, Irtysh basin, West Siberia. Another morphologically and phenotypically similar methanotroph, strain OZ2, was isolated from a sediment of a subarctic freshwater lake, Archangelsk region, northern Russia. Cells of these three strains were Gram-stain-negative, light-pink-pigmented, non-motile, encapsulated, large cocci that contained an intracytoplasmic membrane system typical of type I methanotrophs. They possessed a particulate methane monooxygenase enzyme and utilized only methane and methanol. Strains Sph1T, Sph2 and OZ2 were able to grow at a pH range of 4.0-8.9 (optimum at pH 6.0-7.0) and at temperatures between 2 and 36 °C. Although their temperature optimum was at 20-25 °C, these methanotrophs grew well at lower temperatures, down to 4 °C. The major cellular fatty acids were C16 : 1ω5c, C16 : 1ω6c, C16 : 1ω7c, C16 : 1ω8c, C16 : 0 and C14 : 0; the DNA G+C content was 51.4-51.9 mol%. Strains Sph1T, Sph2 and OZ2 displayed nearly identical (99.1-99.7 % similarity) 16S rRNA gene sequences and belonged to the family Methylococcaceae of the class Gammaproteobacteria. The most closely related organism was Methylovulum miyakonense HT12T (96.0-96.5 % 16S rRNA gene sequence similarity and 90 % pmoA sequence similarity). The novel isolates, however, differed from Methylovulum miyakonense HT12T by cell morphology, pigmentation, absence of soluble methane monooxygenase, more active growth at low temperatures, growth over a broader pH range and higher DNA G+C content. On the basis of these differences, we propose a novel species, Methylovulum psychrotolerans sp. nov., to accommodate these methanotrophs. Strain Sph1T (=LMG 29227T=VKM B-3018T) is the type strain.

  18. [Comparative characterization of cultured methane-oxidizing bacteria by serological and molecular methods].

    Science.gov (United States)

    Slobodova, N V; Kolganova, T V; Bulygina, E S; Kuznetsov, B B; Turova, T P; Kravchenko, I K

    2006-01-01

    Three stable methane-oxidizing enrichment cultures, SB26, SB31, and SB31A were analyzed by transmission electron microscopy and by serological and molecular techniques. Electron microscopy revealed the presence of both type I and type II methanotrophs in SB31 and SB31A enrichments; only type II methanotrophs were found in SB26 enrichment. Methylosinus trichosporium was detected in all three enrichments by the application of species-specific antibodies. Additionally, Methylocystis echinoides was found in SB26 culture; Methyloco