[New antibiotics produced by Bacillus subtilis strains].

Science.gov (United States)

Malanicheva, I A; Kozlov, D G; Efimenko, T A; Zenkova, V A; Kastrukha, G S; Reznikova, M I; Korolev, A M; Borshchevskaia, L N; Tarasova, O D; Sineokiĭ, S P; Efremenkova, O V

2014-01-01

Two Bacillus subtilis strains isolated from the fruiting body of a basidiomycete fungus Pholiota squarrosa exhibited a broad range of antibacterial activity, including those against methicillin-resistant Staphylococcus aureus INA 00761 (MRSA) and Leuconostoc mes6nteroides VKPM B-4177 resistant to glycopep-> tide antibiotics, as well as antifungal activity. The strains were identified as belonging to the "B. subtilis" com- plex based on their morphological and physiological characteristics, as well as by sequencing of the 16S rRNA gene fragments. Both strains (INA 01085 and INA 01086) produced insignificant amounts of polyene antibiotics (hexaen and pentaen, respectively). Strain INA 01086 produced also a cyclic polypeptide antibiotic containing Asp, Gly, Leu, Pro, Tyr, Thr, Trp, and Phe, while the antibiotic of strain INA 01085 contained, apart from these, two unidentified nonproteinaceous amino acids. Both polypeptide antibiotics were new compounds efficient against gram-positive bacteria and able to override the natural bacterial antibiotic resistance.

Probiotic Properties of Exopolysaccharide-Producing Lactobacillus Strains Isolated from Tempoyak

Directory of Open Access Journals (Sweden)

Eilaf Suliman Khalil

2018-02-01

Full Text Available Tempoyak is a functional Malaysian food (an acid-fermented condiment which is produced from the pulp of the durian (Durio zibethinus fruit. The current study aimed to isolate and identify potential exopolysaccharide (EPS-producing Lactobacillus strains from tempoyak for potential use as probiotics. Seven isolates (DUR2, DUR4, DUR5, DUR8, DUR12, DUR18, and DUR20 out of 44 were able to produce EPS, and exhibited resistance to acid and bile salt compared to the reference strains Lactobacillus rhmnosus (ATCC53103 and L. plantarum (ATCC8014. The seven isolated strains belonged to five different species—L. plantarum, L. fermentum, L. crispatus, L. reuteri, and L. pentosus—which were identified using API 50 CHL and 16S rRNA gene sequences (Polymerase chain reaction, PCR – based. The seven strains displayed different ability to produce EPS (100–850 mg/L. Isolates exhibited a high survivability to acid (pH 3.0, bile salts (0.3%, and gastrointestinal tract model (<70%. Results showed that the auto-aggregation and cell surface hydrophobicity ranged from 39.98% to 60.09% and 50.80% to 80.53%, respectively, whereas, the highest co-aggregation value (66.44% was observed by L. fermentum (DUR8 with Pseudomonas aeruginosa. The isolates showed good inhibitory activity against tested pathogens, high antioxidant activity (32.29% to 73.36%, and good ability to reduce cholesterol (22.55% to 75.15%. Thus, the seven tested strains have value as probiotics.

Comparison of Biochemical Activities between High and Low Lipid-Producing Strains of Mucor circinelloides: An Explanation for the High Oleaginicity of Strain WJ11.

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Xin Tang

Full Text Available The oleaginous fungus, Mucor circinelloides, is one of few fungi that produce high amounts of γ-linolenic acid (GLA; however, it usually only produces <25% lipid. Nevertheless, a new strain (WJ11 isolated in this laboratory can produce lipid up to 36% (w/w cell dry weight (CDW. We have investigated the potential mechanism of high lipid accumulation in M. circinelloides WJ11 by comparative biochemical analysis with a low lipid-producing strain, M. circinelloides CBS 277.49, which accumulates less than 15% (w/w lipid. M. circinelloides WJ11 produced more cell mass than that of strain CBS 277.49, although with slower glucose consumption. In the lipid accumulation phase, activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in strain WJ11 were greater than in CBS 277.49 by 46% and 17%, respectively, and therefore may provide more NADPH for fatty acid biosynthesis. The activities of NAD+:isocitrate dehydrogenase and NADP+:isocitrate dehydrogenase, however, were 43% and 54%, respectively, lower in WJ11 than in CBS 277.49 and may retard the tricarboxylic acid cycle and thereby provide more substrate for ATP:citrate lyase (ACL to produce acetyl-CoA. Also, the activities of ACL and fatty acid synthase in the high lipid-producing strain, WJ11, were 25% and 56%, respectively, greater than in strain CBS 277.49. These enzymes may therefore cooperatively regulate the fatty acid biosynthesis in these two strains.

Comparison of Biochemical Activities between High and Low Lipid-Producing Strains of Mucor circinelloides: An Explanation for the High Oleaginicity of Strain WJ11.

Science.gov (United States)

Tang, Xin; Chen, Haiqin; Chen, Yong Q; Chen, Wei; Garre, Victoriano; Song, Yuanda; Ratledge, Colin

2015-01-01

The oleaginous fungus, Mucor circinelloides, is one of few fungi that produce high amounts of γ-linolenic acid (GLA); however, it usually only produces <25% lipid. Nevertheless, a new strain (WJ11) isolated in this laboratory can produce lipid up to 36% (w/w) cell dry weight (CDW). We have investigated the potential mechanism of high lipid accumulation in M. circinelloides WJ11 by comparative biochemical analysis with a low lipid-producing strain, M. circinelloides CBS 277.49, which accumulates less than 15% (w/w) lipid. M. circinelloides WJ11 produced more cell mass than that of strain CBS 277.49, although with slower glucose consumption. In the lipid accumulation phase, activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in strain WJ11 were greater than in CBS 277.49 by 46% and 17%, respectively, and therefore may provide more NADPH for fatty acid biosynthesis. The activities of NAD+:isocitrate dehydrogenase and NADP+:isocitrate dehydrogenase, however, were 43% and 54%, respectively, lower in WJ11 than in CBS 277.49 and may retard the tricarboxylic acid cycle and thereby provide more substrate for ATP:citrate lyase (ACL) to produce acetyl-CoA. Also, the activities of ACL and fatty acid synthase in the high lipid-producing strain, WJ11, were 25% and 56%, respectively, greater than in strain CBS 277.49. These enzymes may therefore cooperatively regulate the fatty acid biosynthesis in these two strains.

Quantitative analysis of the lactic acid and acetaldehyde produced by Streptococcus thermophilus and Lactobacillus bulgaricus strains isolated from traditional Turkish yogurts using HPLC.

Science.gov (United States)

Gezginc, Y; Topcal, F; Comertpay, S; Akyol, I

2015-03-01

The present study was conducted to evaluate the lactic acid- and acetaldehyde-producing abilities of lactic acid bacterial species isolated from traditionally manufactured Turkish yogurts using HPLC. The lactic acid bacterial species purified from the yogurts were the 2 most widely used species in industrial yogurt production: Streptococcus thermophilus and Lactobacillus bulgaricus. These bacteria have the ability to ferment hexose sugars homofermentatively to generate lactic acid and some carbonyl compounds, such as acetaldehyde through pyruvate metabolism. The levels of the compounds produced during fermentation influence the texture and the flavor of the yogurt and are themselves influenced by the chemical composition of the milk, processing conditions, and the metabolic activity of the starter culture. In the study, morphological, biochemical, and molecular characteristics were employed to identify the bacteria obtained from homemade yogurts produced in different regions of Turkey. A collection of 91 Strep. thermophilus and 35 L. bulgaricus strains were investigated for their lactic acid- and acetaldehyde-formation capabilities in various media such as cow milk, LM17 agar, and aerobic-anaerobic SM17 agar or de Man, Rogosa, and Sharpe agar. The amounts of the metabolites generated by each strain in all conditions were quantified by HPLC. The levels were found to vary depending on the species, the strain, and the growth conditions used. Whereas lactic acid production ranged between 0 and 77.9 mg/kg for Strep. thermophilus strains, it ranged from 0 to 103.5 mg/kg for L. bulgaricus. Correspondingly, the ability to generate acetaldehyde ranged from 0 to 105.9 mg/kg in Strep. thermophilus and from 0 to 126.9 mg/kg in L. bulgaricus. Our study constitutes the first attempt to determine characteristics of the wild strains isolated from traditional Turkish yogurts, and the approach presented here, which reveals the differences in metabolite production abilities of the

Comparative Genomics of Acetobacterpasteurianus Ab3, an Acetic Acid Producing Strain Isolated from Chinese Traditional Rice Vinegar Meiguichu.

Science.gov (United States)

Xia, Kai; Li, Yudong; Sun, Jing; Liang, Xinle

2016-01-01

Acetobacter pasteurianus, an acetic acid resistant bacterium belonging to alpha-proteobacteria, has been widely used to produce vinegar in the food industry. To understand the mechanism of its high tolerance to acetic acid and robust ability of oxidizing ethanol to acetic acid (> 12%, w/v), we described the 3.1 Mb complete genome sequence (including 0.28 M plasmid sequence) with a G+C content of 52.4% of A. pasteurianus Ab3, which was isolated from the traditional Chinese rice vinegar (Meiguichu) fermentation process. Automatic annotation of the complete genome revealed 2,786 protein-coding genes and 73 RNA genes. The comparative genome analysis among A. pasteurianus strains revealed that A. pasteurianus Ab3 possesses many unique genes potentially involved in acetic acid resistance mechanisms. In particular, two-component systems or toxin-antitoxin systems may be the signal pathway and modulatory network in A. pasteurianus to cope with acid stress. In addition, the large numbers of unique transport systems may also be related to its acid resistance capacity and cell fitness. Our results provide new clues to understanding the underlying mechanisms of acetic acid resistance in Acetobacter species and guiding industrial strain breeding for vinegar fermentation processes.

Supplementary Material for: In silico screening for candidate chassis strains of free fatty acid-producing cyanobacteria

KAUST Repository

Motwalli, Olaa Amin

2017-01-01

Abstract Background Finding a source from which high-energy-density biofuels can be derived at an industrial scale has become an urgent challenge for renewable energy production. Some microorganisms can produce free fatty acids (FFA) as precursors towards such high-energy-density biofuels. In particular, photosynthetic cyanobacteria are capable of directly converting carbon dioxide into FFA. However, current engineered strains need several rounds of engineering to reach the level of production of FFA to be commercially viable; thus new chassis strains that require less engineering are needed. Although more than 120 cyanobacterial genomes are sequenced, the natural potential of these strains for FFA production and excretion has not been systematically estimated. Results Here we present the FFA SC (FFASC), an in silico screening method that evaluates the potential for FFA production and excretion of cyanobacterial strains based on their proteomes. A literature search allowed for the compilation of 64 proteins, most of which influence FFA production and a few of which affect FFA excretion. The proteins are classified into 49 orthologous groups (OGs) that helped create rules used in the scoring/ranking of algorithms developed to estimate the potential for FFA production and excretion of an organism. Among 125 cyanobacterial strains, FFASC identified 20 candidate chassis strains that rank in their FFA producing and excreting potential above the specifically engineered reference strain, Synechococcus sp. PCC 7002. We further show that the top ranked cyanobacterial strains are unicellular and primarily include Prochlorococcus (order Prochlorales) and marine Synechococcus (order Chroococcales) that cluster phylogenetically. Moreover, two principal categories of enzymes were shown to influence FFA production the most: those ensuring precursor availability for the biosynthesis of lipids, and those involved in handling the oxidative stress associated to FFA synthesis

Triacetic acid lactone production in industrial Saccharomyces yeast strains

Science.gov (United States)

Triacetic acid lactone (TAL) is a potential platform chemical that can be produced in yeast. To evaluate the potential for industrial yeast strains to produce TAL, the g2ps1 gene encoding 2-pyrone synthase was transformed into thirteen industrial yeast strains of varied genetic background. TAL produ...

NEW PRODUCER STRAINS OF BIOBUTANOL. І. ISOLATION AND IDENTIFICATION

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O. A. Tigunova

2013-02-01

Full Text Available Getting new, more productive strains of microorganisms that produce butanol is a topical problem. Studing of morphological and physiological characteristics of the isolated strains, improvement of their cultivation conditions, optimization of biobutanol synthesis gives the possibility to organize a cost-effective butanol production technology. The aim of this work was searching new butanol and butyric acid producer strains, their identification and studying the main steps of the selective strains biosynthesis. The objects of this study were microorganisms that had allocated from soils and sludges samples of Kiev’s lakes. Obtained cultures have been screened. Three strains were obtained as promising and identified as C. acetobutylicum, C. tyrobutylicum, C. butylicum. Selective medium have been developed and modified for the microorganisms. Producer’s features were investigated in order to maximize the accumulation of target metabolites.

Selection of tannase-producing Aspergillus niger strains

OpenAIRE

Pinto,Gustavo A.S.; Leite,Selma G.F.; Terzi,Selma C.; Couri,Sonia

2001-01-01

The aim of this work was to select strains of Aspergillus niger for tannase production. Growth of colonies in plates with tannic acid-containing medium indicated their ability to synthesize tannase. Tannase activity was also measured in solid-state fermentation. A. niger 11T25A5 was the best tannase producer (67.5 U.g-1/72 hours of fermentation).

Isolation of gallic acid-producing microorganisms and their use in ...

African Journals Online (AJOL)

A total number of eighty gallic acid producing strains were isolated from forest soil or plant samples. Among these strains, thirteen isolates were selected for gallic acid production and these isolates were Aspergillus niger 1, A. niger 2, A. niger 3, Penicillium canescens (3), P. frequentans (2), P. spinulosum (2), ...

Strain-related acid production by oral streptococci

DEFF Research Database (Denmark)

de Soet, JJ; Nyvad, Bente; Kilian, Mogens

2000-01-01

Acid production, in particular at low pH, is thought to be an important ecological determinant in dental caries. The aim of the present study was to determine the acid producing capability at different pH levels of 47 streptococcal strains, representing 9 species, isolated from human dental plaque....... The bacteria were grown until mid log-phase under anaerobic conditions and acid production was measured in a pH-stat system at pH 7.0, 6.0, 5.5 and 5.0. At all pH values, the mean velocity of acid production (V(ap)) by Streptococcus mutans and S. sobrinus was significantly higher (p... that of the other oral streptococci, including S. mitis, S. oralis, S. gordonii, S. sanguis, S. intermedius, S. anginosus, S. constellatus, and S. vestibularis. However, the V(ap) of some strains of S. mitis biovar 1 and S. oralis, particularly at pH values of 7.0 and 6.0, exceeded that of some strains of S. mutans...

Technological and safety properties of newly isolated GABA-producing Lactobacillus futsaii strains.

Science.gov (United States)

Sanchart, C; Rattanaporn, O; Haltrich, D; Phukpattaranont, P; Maneerat, S

2016-09-01

To evaluate the technological and safety properties of Lactobacillus futsaii CS3 and CS5 isolated from Thai fermented shrimp products (Kung-Som) in order to develop a valuable gamma-aminobutyric acid (GABA)-producing starter culture. Both strains showed a high GABA-producing ability (>8 mg ml(-1) ) in MRS broth containing 20 mg ml(-1) monosodium glutamate (MSG) for 120 h. They also exhibited inhibitory activity against foodborne pathogens and spoilage bacteria. Cell surface hydrophobicity and proteolytic activity were observed in both strains. Strain CS3 survived better under simulated gastrointestinal tract conditions with only 1·5 log-units cell decrease over 8 h. Both strains showed the ability to deconjugate taurocholate and taurodeoxycholate acid. Neither virulence genes nor biogenic amine production was detected. Strain CS3 exhibited susceptibility to all tested antibiotics with the exception of vancomycin, while strain CS5 showed resistance to vancomycin, ampicillin and chloramphenicol. Based on the results obtained, Lact. futsaii CS3 is very promising as a GABA-producing and potentially probiotic starter culture strain for applications in functional fermented foods. This study focuses on the technological and safety characteristics of Lact. futsaii CS3 and CS5 including their high GABA-producing capacity for the first time. This provides a way of replacing chemical GABA by natural GABA using a GABA-producing starter culture candidate, at the same time offering the consumer new attractive food products. © 2016 The Society for Applied Microbiology.

Comparative genomics of citric-acid-producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88

DEFF Research Database (Denmark)

Andersen, Mikael Rørdam; Salazar, Margarita Pena; Schaap, Peter J.

2011-01-01

The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme......-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compel additional exploration. We therefore undertook whole-genome sequencing of the acidogenic A. niger wild-type strain (ATCC 1015) and produced a genome sequence of very high quality. Only 15...

Screening on Gibberellic Acid Producing Activity of Azospirillum Isolates

International Nuclear Information System (INIS)

Shun Lai Ei; Khin Mya Lwin; Myo Myint

2010-12-01

Six strains of Azopirillum spp were isolated from rice, sugarcane, corn, maize, sunflower and pepper roots and screened the gibberellic acid productivity. Only three strains of Azospirillum species showed the activity and were indentified by cultural, biochemical and drug sensitivity patterns. Among them,one strain isolated from rice root can produce microbial gibberellic acid. It showed greenish yellow colour in chromatogram under UV absorption. This screening method was studied from 1 to 14 days incubation. Qualitative measurement of GA productivity was determined by thin layer chromatography.

Comparative genomics of citric-acid-producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88

Science.gov (United States)

Andersen, Mikael R.; Salazar, Margarita P.; Schaap, Peter J.; van de Vondervoort, Peter J.I.; Culley, David; Thykaer, Jette; Frisvad, Jens C.; Nielsen, Kristian F.; Albang, Richard; Albermann, Kaj; Berka, Randy M.; Braus, Gerhard H.; Braus-Stromeyer, Susanna A.; Corrochano, Luis M.; Dai, Ziyu; van Dijck, Piet W.M.; Hofmann, Gerald; Lasure, Linda L.; Magnuson, Jon K.; Menke, Hildegard; Meijer, Martin; Meijer, Susan L.; Nielsen, Jakob B.; Nielsen, Michael L.; van Ooyen, Albert J.J.; Pel, Herman J.; Poulsen, Lars; Samson, Rob A.; Stam, Hein; Tsang, Adrian; van den Brink, Johannes M.; Atkins, Alex; Aerts, Andrea; Shapiro, Harris; Pangilinan, Jasmyn; Salamov, Asaf; Lou, Yigong; Lindquist, Erika; Lucas, Susan; Grimwood, Jane; Grigoriev, Igor V.; Kubicek, Christian P.; Martinez, Diego; van Peij, Noël N.M.E.; Roubos, Johannes A.; Nielsen, Jens; Baker, Scott E.

2011-01-01

The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compel additional exploration. We therefore undertook whole-genome sequencing of the acidogenic A. niger wild-type strain (ATCC 1015) and produced a genome sequence of very high quality. Only 15 gaps are present in the sequence, and half the telomeric regions have been elucidated. Moreover, sequence information from ATCC 1015 was used to improve the genome sequence of CBS 513.88. Chromosome-level comparisons uncovered several genome rearrangements, deletions, a clear case of strain-specific horizontal gene transfer, and identification of 0.8 Mb of novel sequence. Single nucleotide polymorphisms per kilobase (SNPs/kb) between the two strains were found to be exceptionally high (average: 7.8, maximum: 160 SNPs/kb). High variation within the species was confirmed with exo-metabolite profiling and phylogenetics. Detailed lists of alleles were generated, and genotypic differences were observed to accumulate in metabolic pathways essential to acid production and protein synthesis. A transcriptome analysis supported up-regulation of genes associated with biosynthesis of amino acids that are abundant in glucoamylase A, tRNA-synthases, and protein transporters in the protein producing CBS 513.88 strain. Our results and data sets from this integrative systems biology analysis resulted in a snapshot of fungal evolution and will support further optimization of cell factories based on filamentous fungi. PMID:21543515

Nesterenkonia sp. strain F, a halophilic bacterium producing acetone, butanol, and ethanol under aerobic conditions.

Science.gov (United States)

Amiri, Hamid; Azarbaijani, Reza; Parsa Yeganeh, Laleh; Shahzadeh Fazeli, Abolhassan; Tabatabaei, Meisam; Salekdeh, Ghasem Hosseini; Karimi, Keikhosro

2016-01-04

The moderately halophilic bacterium Nesterenkonia sp. strain F, which was isolated from Aran-Bidgol Lake (Iran), has the ability to produce acetone, butanol, and ethanol (ABE) as well as acetic and butyric acids under aerobic and anaerobic conditions. This result is the first report of ABE production with a wild microorganism from a family other than Clostridia and also the first halophilic species shown to produce butanol under aerobic cultivation. The cultivation of Nesterenkonia sp. strain F under anaerobic conditions with 50 g/l of glucose for 72 h resulted in the production of 105 mg/l of butanol, 122 mg/l of acetone, 0.2 g/l of acetic acid, and 2.5 g/l of butyric acid. Furthermore, the strain was cultivated on media with different glucose concentrations (20, 50, and 80 g/l) under aerobic and anaerobic conditions. Through fermentation with a 50 g/l initial glucose concentration under aerobic conditions, 66 mg/l of butanol, 125 mg/l of acetone, 291 mg/l of ethanol, 5.9 g/l of acetic acid, and 1.2 g/l of butyric acid were produced. The enzymes pertaining to the fermentation pathway in the strain were compared with the enzymes of Clostridium spp., and the metabolic pathway of fermentation used by Nesterenkonia sp. strain F was investigated.

Screening local Lactobacilli from Iran in terms of production of lactic acid and identification of superior strains

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Fatemeh Soleimanifard

2015-12-01

Full Text Available Introduction: Lactobacilli are a group of lactic acid bacteria that their final product of fermentation is lactic acid. The objective of this research is selection of local Lactobacilli producing L (+ lactic acid. Materials and methods: In this research the local strains were screened based on the ability to produce lactic acid. The screening was performed in two stages. The first stage was the titration method and the second stage was the enzymatic method. The superior strains obtained from titration method were selected to do enzymatic test. Finally, the superior strains in the second stage (enzymatic which had the ability to produce L(+ lactic acid were identified by biochemical tests. Then, molecular identification of strains was performed by using 16S rRNA sequencing. Results: In this study, the ability of 79 strains of local Lactobacilli in terms of production of lactic acid was studied. The highest and lowest rates of lactic acid production was 34.8 and 12.4 mg/g. Superior Lactobacilli in terms of production of lactic acid ability of producing had an optical isomer L(+, the highest levels of L(+ lactic acid were with 3.99 and the lowest amount equal to 1.03 mg/g. The biochemical and molecular identification of superior strains showed that strains are Lactobacillus paracasei. Then the sequences of 16S rRNA of superior strains were reported in NCBI with accession numbers KF735654، KF735655، KJ508201and KJ508202. Discussion and conclusion: The amounts of lactic acid production by local Lactobacilli were very different and producing some of these strains on available reports showed more products. The results of this research suggest the use of superior strains of Lactobacilli for production of pure L(+ lactic acid.

Isolation of a high malic and low acetic acid-producing sake yeast Saccharomyces cerevisiae strain screened from respiratory inhibitor 2,4-dinitrophenol (DNP)-resistant strains.

Science.gov (United States)

Kosugi, Shingo; Kiyoshi, Keiji; Oba, Takahiro; Kusumoto, Kenichi; Kadokura, Toshimori; Nakazato, Atsumi; Nakayama, Shunichi

2014-01-01

We isolated 2,4-dinitrophenol (DNP)-resistant sake yeast strains by UV mutagenesis. Among the DNP-resistant mutants, we focused on strains exhibiting high malic acid and low acetic acid production. The improved organic acid composition is unlikely to be under the control of enzyme activities related to malic and acetic acid synthesis pathways. Instead, low mitochondrial activity was observed in DNP-resistant mutants, indicating that the excess pyruvic acid generated during glycolysis is not metabolized in the mitochondria but converted to malic acid in the cytosol. In addition, the NADH/NAD(+) ratio of the DNP-resistant strains was higher than that of the parental strain K901. These results suggest that the increased NADH/NAD(+) ratio together with the low mitochondrial activity alter the organic acid composition because malic acid synthesis requires NADH, while acetic acid uses NAD(+). Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Relationship of Quantity of Citric Acid and Protein Content of Mycelia during Citric Acid Production by Three Strains of Aspergillus niger

International Nuclear Information System (INIS)

Abdullah-Al-Mahin; Alamgir Z. Chowdhury; Rehana Begum

2006-01-01

The amount of protein in the surface grown mycelia of three strains of Aspergillus niger (CA16,79/20 and 318) was found to decrease with the increase of citric acid production in sucrose based fermentation medium. Throughout the study period of 6 to 10 days of fermentation, highest amount of citric acid was produced by Aspergillus niger 318 although the amount of protein in mycelia was lowest for this strain. On the other hand, lowest amount of citric acid was produced by the strain CA 16 which in tern produced highest amount of mycelial protein. Aspergillus niger 79/20 produced both intermediate level of protein and citric acid. The Protein was estimated by three commonly used methods namely: Kjeldahl, Biuret and Lowry methods. Kjeldahl and Lowry method gave the highest and lowest results respectively for protein determination in all cases.(authors)

Bio-succinic acid production: Escherichia coli strains design from genome-scale perspectives

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Bashir Sajo Mienda

2017-10-01

Full Text Available Escherichia coli (E. coli has been established to be a native producer of succinic acid (a platform chemical with different applications via mixed acid fermentation reactions. Genome-scale metabolic models (GEMs of E. coli have been published with capabilities of predicting strain design strategies for the production of bio-based succinic acid. Proof-of-principle strains are fundamentally constructed as a starting point for systems strategies for industrial strains development. Here, we review for the first time, the use of E. coli GEMs for construction of proof-of-principles strains for increasing succinic acid production. Specific case studies, where E. coli proof-of-principle strains were constructed for increasing bio-based succinic acid production from glucose and glycerol carbon sources have been highlighted. In addition, a propose systems strategies for industrial strain development that could be applicable for future microbial succinic acid production guided by GEMs have been presented.

Comparative genomics of citric-acid producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88

Energy Technology Data Exchange (ETDEWEB)

Andersen, Mikael R.; Salazar, Margarita; Schaap, Peter; van de Vondervoort, Peter; Culley, David E.; Thykaer, Jette; Frisvad, Jens C.; Nielsen, Kristian F.; Albang, Richard; Albermann, Kaj; Berka, Randy; Braus, Gerhard; Braus-Stromeyer, Susanna A.; Corrochano, Luis; Dai, Ziyu; van Dijck, Piet; Hofmann, Gerald; Lasure, Linda L.; Magnuson, Jon K.; Menke, Hildegard; Meijer, Martin; Meijer, Susan; Nielsen, Jakob B.; Nielsen, Michael L.; van Ooyen, Albert; Pel, Herman J.; Poulsen, Lars; Samson, Rob; Stam, Hein; Tsang, Adrian; van den Brink, Johannes M.; ATkins, Alex; Aerts, Andrea; Shapiro, Harris; Pangilinan, Jasmyn; Salamov, Asaf; Lou, Yigong; Lindquist, Erika; Lucas, Susan; Grimwood, Jane; Grigoriev, Igor V.; Kubicek, Christian P.; Martinez, Diego; van Peij, Noel; Roubos, Johannes A.; Nielsen, Jens B.; Baker, Scott E.

2011-06-01

The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compels additional exploration. We therefore undertook whole genome sequencing of the acidogenic A. niger wild type strain (ATCC 1015), and produced a genome sequence of very high quality. Only 15 gaps are present in the sequence and half the telomeric regions have been elucidated. Moreover, sequence information from ATCC 1015 was utilized to improve the genome sequence of CBS 513.88. Chromosome-level comparisons uncovered several genome rearrangements, deletions, a clear case of strain-specific horizontal gene transfer, and identification of 0.8 megabase of novel sequence. Single nucleotide polymorphisms per kilobase (SNPs/kb) between the two strains were found to be exceptionally high (average: 7.8, maximum: 160 SNPs/kb). High variation within the species was confirmed with exo-metabolite profiling and phylogenetics. Detailed lists of alleles were generated, and genotypic differences were observed to accumulate in metabolic pathways essential to acid production and protein synthesis. A transcriptome analysis revealed up-regulation of the electron transport chain, specifically the alternative oxidative pathway in ATCC 1015, while CBS 513.88 showed significant up regulation of genes associated with biosynthesis of amino acids that are abundant in glucoamylase A, tRNA-synthases and protein transporters.

POTENTIAL PRODUCTION OF CYCLOPIAZONIC ACID BY PENICILLIUM CAMEMBERTI STRAINS ISOLATED FROM CAMEMBERT TYPE CHEESE

Directory of Open Access Journals (Sweden)

Miroslava Císarová

2012-10-01

Full Text Available The aim of this study was to isolate the strains of fungi from Camembert type cheese, identify them and to test isolated strains of Penicillium camemberti for their ability to produce cyclopiazonic acid. The description of micro- and macromorphological features was used for identification of Penicillium camemberti strains. Strains were subsequently in vitro tested on their potential ability to produce mycotoxin cyclopiazonic acid (CPA. All of the 14 strains of Penicillium camemberti, which were obtained from 20 samples of Camembert type cheese, were cultivated 7, 14, 21, 27 and 30 days on CYA medium at 10±1°C, 15±1°C and 25±1°C in the dark. For determination of CPA production ability by P. camemberti isolates in vitro was TLC used. After 7 days of cultivation cyclopiazonic acid was produced only by 5 from 14 strains cultivated at all cultivation temperatures. After 14 and 21 days of cultivation was CPA produced by 6 strains at all of cultivation temperatures. After 27 and 30 days of cultivation was CPA identified in 7 strains cultivated at all temperatures of cultivation. The other strains also produced mycotoxin, however, not at each temperature. The most productive at all temperatures and after all days were 5 out of 14 tested strains (S9, S10, S13, S18 and S19. Strains S6 and S16 did not produce CPA at any temperature. The lowest production after all days of cultivation was found at 10±1 °C (44% and the highest at 25±1 °C (85%.

Genome Sequence of Lactococcus lactis subsp. lactis NCDO 2118, a GABA-Producing Strain

DEFF Research Database (Denmark)

Oliveira, Letícia C; Saraiva, Tessália D L; Soares, Siomar C

2014-01-01

Lactococcus lactis subsp. lactis NCDO 2118 is a nondairy lactic acid bacterium, a xylose fermenter, and a gamma-aminobutyric acid (GABA) producer isolated from frozen peas. Here, we report the complete genome sequence of L. lactis NCDO 2118, a strain with probiotic potential activity....

Characterisation of the exopolysaccharide (EPS)-producing Lactobacillus paraplantarum BGCG11 and its non-EPS producing derivative strains as potential probiotics.

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Nikolic, Milica; López, Patricia; Strahinic, Ivana; Suárez, Ana; Kojic, Milan; Fernández-García, María; Topisirovic, Ljubisa; Golic, Natasa; Ruas-Madiedo, Patricia

2012-08-17

Traditional fermented foods are the best source for the isolation of strains with specific traits to act as functional starters and to keep the biodiversity of the culture collections. Besides, these strains could be used in the formulation of foods claimed to promote health benefits, i.e. those containing probiotic microorganisms. For the rational selection of strains acting as probiotics, several in vitro tests have been proposed. In the current study, we have characterized the probiotic potential of the strain Lactobacillus paraplantarum BGCG11, isolated from a Serbian soft, white, homemade cheese, which is able to produce a "ropy" exopolysaccharide (EPS). Three novobiocin derivative strains, which have lost the ropy phenotype, were characterized as well in order to determine the putative role of the EPS in the probiotic potential. Under chemically gastrointestinal conditions, all strains were able to survive around 1-2% (10(6)-10(7)cfu/ml cultivable bacteria) only when they were included in a food matrix (1% skimmed milk). The strains were more resistant to acid conditions than to bile salts and gastric or pancreatic enzymes, which could be due to a pre-adaptation of the parental strain to acidic conditions in the cheese habitat. The ropy EPS did not improve the survival of the producing strain. On the contrary, the presence of an EPS layer surrounding the strain BGCG11 hindered its adhesion to the three epithelial intestinal cell lines tested, since the adhesion of the three non-ropy derivatives was higher than the parental one and also than that of the reference strain Lactobacillus rhamnosus GG. Aiming to propose a potential target application of these strains as probiotics, the cytokine production of peripheral blood mononuclear cells (PBMC) was analyzed. The EPS-producing L. paraplantarum BGCG11 strain showed an anti-inflammatory or immunosuppressor profile whereas the non-ropy derivative strains induced higher pro-inflammatory response. In addition, when

Simultaneous production of acetic and gluconic acids by a thermotolerant Acetobacter strain during acetous fermentation in a bioreactor.

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Mounir, Majid; Shafiei, Rasoul; Zarmehrkhorshid, Raziyeh; Hamouda, Allal; Ismaili Alaoui, Mustapha; Thonart, Philippe

2016-02-01

The activity of bacterial strains significantly influences the quality and the taste of vinegar. Previous studies of acetic acid bacteria have primarily focused on the ability of bacterial strains to produce high amounts of acetic acid. However, few studies have examined the production of gluconic acid during acetous fermentation at high temperatures. The production of vinegar at high temperatures by two strains of acetic acid bacteria isolated from apple and cactus fruits, namely AF01 and CV01, respectively, was evaluated in this study. The simultaneous production of gluconic and acetic acids was also examined in this study. Biochemical and molecular identification based on a 16s rDNA sequence analysis confirmed that these strains can be classified as Acetobacter pasteurianus. To assess the ability of the isolated strains to grow and produce acetic acid and gluconic acid at high temperatures, a semi-continuous fermentation was performed in a 20-L bioreactor. The two strains abundantly grew at a high temperature (41°C). At the end of the fermentation, the AF01 and CV01 strains yielded acetic acid concentrations of 7.64% (w/v) and 10.08% (w/v), respectively. Interestingly, CV01 was able to simultaneously produce acetic and gluconic acids during acetic fermentation, whereas AF01 mainly produced acetic acid. In addition, CV01 was less sensitive to ethanol depletion during semi-continuous fermentation. Finally, the enzymatic study showed that the two strains exhibited high ADH and ALDH enzyme activity at 38°C compared with the mesophilic reference strain LMG 1632, which was significantly susceptible to thermal inactivation. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Metabolic evolution of Escherichia coli strains that produce organic acids

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Grabar, Tammy; Gong, Wei; Yocum, R Rogers

2014-10-28

This invention relates to the metabolic evolution of a microbial organism previously optimized for producing an organic acid in commercially significant quantities under fermentative conditions using a hexose sugar as sole source of carbon in a minimal mineral medium. As a result of this metabolic evolution, the microbial organism acquires the ability to use pentose sugars derived from cellulosic materials for its growth while retaining the original growth kinetics, the rate of organic acid production and the ability to use hexose sugars as a source of carbon. This invention also discloses the genetic change in the microorganism that confers the ability to use both the hexose and pentose sugars simultaneously in the production of commercially significant quantities of organic acids.

Fate of acid-resistant and non-acid resistant Shiga toxin-producing Escherichia coli strains in experimentally contaminated French fermented raw meat sausages.

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Montet, M P; Christieans, S; Thevenot, D; Coppet, V; Ganet, S; Muller, M L Delignette; Dunière, L; Miszczycha, S; Vernozy-Rozand, C

2009-02-28

Both pathogenic and nonpathogenic E. coli exhibit a stress response to sublethal environmental stresses. Several studies have reported acid tolerance and survival characteristics of E. coli O157:H7 in foodstuffs, but there are few reports about the tolerance of non-O157 serogroups (STEC) to organic acids in foods. The purpose of this study was to examine the effect of the manufacturing process of French fermented raw meat sausages on the growth and survival of acid-resistant (AR) and non-acid resistant (NAR) STEC strains. The six strains, 3 AR and 3 NAR, were inoculated separately into raw sausage mixture at a level of 10(4)-10(5) CFU/g. A total of 19 batches of sausages were manufactured. A rapid and similar decrease in the number of both AR and NAR STEC strains, from less than 1 to 1.5 log(10) CFU/g, was observed during the first 5 days of fermentation at 20-24 degrees C. This rapid decrease was followed by a more gradual but continuous decrease in STEC counts after drying at 13-14 degrees C, up to day 35. The STEC counts were <10 CFU/g after 35 days for the NAR strains and the same concentration for the AR strains on the best before date (day 60). It was not possible to detect any NAR STEC after 60 days. The present study shows that the process used in the manufacture of French sausages results in a complete destruction of NAR STEC strains after 60 days, but it does not have the same effect on the AR STEC strains.

Characterization of volatile compounds produced by Lactobacillus helveticus strains in a hard cheese model.

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Cuffia, Facundo; Bergamini, Carina V; Wolf, Irma V; Hynes, Erica R; Perotti, María C

2018-01-01

Starter cultures of Lactobacillus helveticus used in hard cooked cheeses play an important role in flavor development. In this work, we studied the capacity of three strains of L. helveticus, two autochthonous (Lh138 and Lh209) and one commercial (LhB02), to grow and to produce volatile compounds in a hard cheese extract. Bacterial counts, pH, profiles of organic acids, carbohydrates, and volatile compounds were analyzed during incubation of extracts for 14 days at 37 ℃. Lactobacilli populations were maintained at 10 6 CFU ml -1 for Lh138, while decreases of approx. 2 log orders were found for LhB02 and Lh209. Both Lh209 and LhB02 slightly increased the acetic acid content whereas mild increase in lactic acid was produced by Lh138. The patterns of volatiles were dependent on the strain which reflect their distinct enzymatic machineries: LhB02 and Lh209 produced a greater diversity of compounds, while Lh138 was the least producer strain. Extracts inoculated with LhB02 and Lh 209 were characterized by ketones, esters, alcohols, aldehydes, and acids, whereas in the extracts with Lh138 the main compounds belonged to aromatic, aldehydes, and ketones groups. Therefore, Lh209 and LhB02 could represent the best cheese starters to improve and intensify the flavor, and even a starter composed by combinations of LhB02 or Lh209 with Lh138 could also be a strategy to diversify cheese flavor.

Evaluation of commercial soy sauce koji strains of Aspergillus oryzae for γ-aminobutyric acid (GABA) production.

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Ab Kadir, Safuan; Wan-Mohtar, Wan Abd Al Qadr Imad; Mohammad, Rosfarizan; Abdul Halim Lim, Sarina; Sabo Mohammed, Abdulkarim; Saari, Nazamid

2016-10-01

In this study, four selected commercial strains of Aspergillus oryzae were collected from soy sauce koji. These A. oryzae strains designated as NSK, NSZ, NSJ and NST shared similar morphological characteristics with the reference strain (A. oryzae FRR 1675) which confirmed them as A. oryzae species. They were further evaluated for their ability to produce γ-aminobutyric acid (GABA) by cultivating the spore suspension in a broth medium containing 0.4 % (w/v) of glutamic acid as a substrate for GABA production. The results showed that these strains were capable of producing GABA; however, the concentrations differed significantly (P sauce production.

Gallic acid production under anaerobic submerged fermentation by two bacilli strains.

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Aguilar-Zárate, Pedro; Cruz, Mario A; Montañez, Julio; Rodríguez-Herrera, Raúl; Wong-Paz, Jorge E; Belmares, Ruth E; Aguilar, Cristóbal N

2015-12-30

Tannase is an enzyme that catalyses the breakdown of ester bonds in gallotannins such as tannic acid. In recent years, the interest on bacterial tannases has increased because of its wide applications. The lactic acid bacteria (LAB) plays an important role in food tannin biotransformation, it has the ability of hydrolyse tannins in ruminants intestine. The finding of tannin hydrolysis by LAB has sparked their use as tannase producer. The bacterial strains used in the present work were identified as Bacillus subtilis AM1 and Lactobacillus plantarum CIR1. The maximal tannase production levels were 1400 and 1239 U/L after 32 and 36 h of fermentation respectively, for B. subtilis AM1 and L. plantarum CIR1. Maximum gallic acid release was 24.16 g/L for B. subtilis AM1 and 23.73 g/L for L. plantarum CIR1. HPLC analysis showed the formation of another peaks in the retention time range of 9-14 min, which could be attributed to the formation of di or tri-galloyl glucose. According to database, the strains were identified as Bacillus subtilis AM1 and Lactobacillus plantarum CIR1. In conclusion, both strains had the capability to produce good titres of extracellular tannase and release gallic acid.

Metabolic Engineering of Yeast to Produce Fatty Acid-derived Biofuels: Bottlenecks and Solutions

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Jiayuan eSheng

2015-06-01

Full Text Available Fatty acid-derived biofuels can be a better solution than bioethanol to replace petroleum fuel, since they have similar energy content and combustion properties as current transportation fuels. The environmentally friendly microbial fermentation process has been used to synthesize advanced biofuels from renewable feedstock. Due to their robustness as well as the high tolerance to fermentation inhibitors and phage contamination, yeast strains such as Saccharomyces cerevisiae and Yarrowia lipolytica have attracted tremendous attention in recent studies regarding the production of fatty acid-derived biofuels, including fatty acids, fatty acid ethyl esters, fatty alcohols, and fatty alkanes. However, the native yeast strains cannot produce fatty acids and fatty acid-derived biofuels in large quantities. To this end, we have summarized recent publications in this review on metabolic engineering of yeast strains to improve the production of fatty acid-derived biofuels, identified the bottlenecks that limit the productivity of biofuels, and categorized the appropriate approaches to overcome these obstacles.

Strain improvement and metabolic flux analysis in the wild-type and a mutant Lactobacillus lactis strain for L(+)-lactic acid production.

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Bai, Dong-Mei; Zhao, Xue-Ming; Li, Xin-Gang; Xu, Shi-Min

2004-12-20

The effects of initial glucose concentration and calcium lactate concentration on the lactic acid production by the parent strain, Lactobacillus lactis BME5-18, were studied. The results of the experiments indicated that glucose and lactate repressed the cell growth and the lactic acid production by Lactobacillus lactis BME5-18. A L(+)-lactic acid overproducing strain, Lactobacillus lactis BME5-18M, was screened by mutagenizing the parent strain with ultraviolet (UV) light irradiation and selecting the high glucose and lactate calcium concentration repression resistant mutant. Starting with a concentration of 100g L(-1) glucose, the mutant produced 98.6 g L(-1) lactic acid after 60 h in flasks, 73.9% higher than that of the parent strain. The L(+)-lactic acid purity was 98.1% by weight based on the amount of total lactic acid. The culture of the parent strain could not be analyzed well by conventional metabolic flux analysis techniques, since some pyruvate were accumulated intracellularly. Therefore, a revised flux analysis method was proposed by introducing intracellular pyruvate pool. Further studies demonstrate that there is a high level of NADH oxidase activity (12.11 mmol mg(-1) min(-1)) in the parent strain. The molecular mechanisms of the strain improvement were proposed, i.e., the high level of NADH oxidase activity was eliminated and the uptake rate of glucose was increased from 82.1 C-mmol (g DW h)(-1) to 98.9 C-mmol (g DW h)(-1) by mutagenizing the parent strain with UV, and therefore the mutant strain converts mostly pyruvate to lactic acid with a higher productivity (1.76 g L(-1) h(-1)) than the parent strain (0.95 g L(-1) h(-1)).

The effects of abscisic acid, salicylic acid and jasmonic acid on lipid accumulation in two freshwater Chlorella strains.

Science.gov (United States)

Wu, Guanxun; Gao, Zhengquan; Du, Huanmin; Lin, Bin; Yan, Yuchen; Li, Guoqiang; Guo, Yanyun; Fu, Shenggui; Wei, Gongxiang; Wang, Miaomiao; Cui, Meng; Meng, Chunxiao

2018-03-27

Sustainable renewable energy is being hotly debated globally because the continued use of finite fossil fuels is now widely recognized as being unsustainable. Microalgae potentially offer great opportunities for resolving this challenge. Abscisic acid (ABA), jasmonic acid (JA) and salicylic acid (SA) are involved in regulating many physiological properties and have been widely used in higher plants. To test if phytohormones have an impact on accumulating lipid for microalgae, ABA, JA and SA were used to induce two Chlorella strains in the present study. The results showed 1.0 mg/L ABA, 10 mg/L SA, and 0.5 mg/L JA, led strain C. vulgaris ZF strain to produce a 45%, 42% and 49% lipid content that was 1.8-, 1.7- and 2.0-fold that of controls, respectively. For FACHB 31 (number 31 of the Freshwater Algae Culture Collection at the Institute of Hydrobiology, Chinese Academy of Sciences), the addition of 1.0 mg/L ABA, 10 mg/L SA, and 0.5 mg/L, JA produced 33%, 30% and 38% lipid content, which was 1.8-, 1.6- and 2.1-fold that of controls, respectively. As for lipid productivity, 1.0 mg/L ABA increased the lipid productivity of C. vulgaris ZF strain and FACHB-31 by 123% and 44%; 10 mg/L SA enhanced lipid productivity by 100% and 33%; the best elicitor, 0.5 mg/L JA, augmented lipid productivity by 127% and 75% compared to that of controls, respectively. The results above suggest that the three phytohormones at physiological concentrations play crucial roles in inducing lipid accumulation in Chlorella.

Non-sterilized fermentation of high optically pure D-lactic acid by a genetically modified thermophilic Bacillus coagulans strain.

Science.gov (United States)

Zhang, Caili; Zhou, Cheng; Assavasirijinda, Nilnate; Yu, Bo; Wang, Limin; Ma, Yanhe

2017-11-25

Optically pure D-lactic acid (≥ 99%) is an important precursor of polylactic acid. However, there are relatively few studies on D-lactic acid fermentation compared with the extensive investigation of L-lactic acid production. Most lactic acid producers are mesophilic organisms. Optically pure D-lactic acid produced at high temperature not only could reduce the costs of sterilization but also could inhibit the growth of other bacteria, such as L-lactic acid producers. Thermophilic Bacillus coagulans is an excellent producer of L-lactic acid with capable of growing at 50 °C. In our previous study, the roles of two L-lactic acid dehydrogenases have been demonstrated in B. coagulans DSM1. In this study, the function of another annotated possible L-lactate dehydrogenase gene (ldhL3) was verified to be leucine dehydrogenase with an activity of 0.16 units (μmol/min) per mg protein. Furthermore, the activity of native D-lactate dehydrogenase was too low to support efficient D-lactic acid production, even under the control of strong promoter. Finally, an engineered B. coagulans D-DSM1 strain with the capacity for efficient production of D-lactic acid was constructed by deletion of two L-lactate dehydrogenases genes (ldhL1 and ldhL2) and insertion of the D-lactate dehydrogenase gene (LdldhD) from Lactobacillus delbrueckii subsp. bulgaricus DSM 20081 at the position of ldhL1. This genetically engineered strain produced only D-lactic acid under non-sterilized condition, and finally 145 g/L of D-lactic acid was produced with an optical purity of 99.9% and a high yield of 0.98 g/g. This is the highest optically pure D-lactic acid titer produced by a thermophilic strain.

Global insights into acetic acid resistance mechanisms and genetic stability of Acetobacter pasteurianus strains by comparative genomics

Science.gov (United States)

Wang, Bin; Shao, Yanchun; Chen, Tao; Chen, Wanping; Chen, Fusheng

2015-12-01

Acetobacter pasteurianus (Ap) CICC 20001 and CGMCC 1.41 are two acetic acid bacteria strains that, because of their strong abilities to produce and tolerate high concentrations of acetic acid, have been widely used to brew vinegar in China. To globally understand the fermentation characteristics, acid-tolerant mechanisms and genetic stabilities, their genomes were sequenced. Genomic comparisons with 9 other sequenced Ap strains revealed that their chromosomes were evolutionarily conserved, whereas the plasmids were unique compared with other Ap strains. Analysis of the acid-tolerant metabolic pathway at the genomic level indicated that the metabolism of some amino acids and the known mechanisms of acetic acid tolerance, might collaboratively contribute to acetic acid resistance in Ap strains. The balance of instability factors and stability factors in the genomes of Ap CICC 20001 and CGMCC 1.41 strains might be the basis for their genetic stability, consistent with their stable industrial performances. These observations provide important insights into the acid resistance mechanism and the genetic stability of Ap strains and lay a foundation for future genetic manipulation and engineering of these two strains.

Study on the IAA (Indole acetic acid) Productivity of Soil Yeast Strain Isolats

International Nuclear Information System (INIS)

Nwe Nwe Soe Hlaing; Swe Zin Yu; San San Yu

2011-12-01

Twelve isolated soil yeast were tested in IAA production in peptone yeast glucose broth (PYG). All strains were screened for the Indole Acetic Acid (IAA) producing activity in PYG broth supplemented with or without L-Tryptophan (L-TRP) as precusor. IAA production was assayed calorimetrically using Salkowski's reagent. The concentration of IAA produced by yeast strains was measured by spectrophotometric method at 530nm. Y6 strain was the highest IAA producer (79ppm) at 9 days incubation period without tryptophan. Y3, Y10 and Y12 strains that were incubated without L-TRP also had the higher ability in the production of IAA than other yeast isolates. The selected yeasts having high IAA production activity were characterized by morphological study and biochemical tests including sugar assimilation and fermentation tests.

Effect of γ-Aminobutyric Acid-producing Strain on Laying Performance, Egg Quality and Serum Enzyme Activity in Hy-Line Brown Hens under Heat Stress

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Y. Z. Zhu

2015-07-01

Full Text Available Heat-stress remains a costly issue for animal production, especially for poultry as they lack sweat glands, and alleviating heat-stress is necessary for ensuring animal production in hot environment. A high γ-aminobutyric acid (GABA-producer Lactobacillus strain was used to investigate the effect of dietary GABA-producer on laying performance and egg quality in heat-stressed Hy-line brown hens. Hy-Line brown hens (n = 1,164 at 280 days of age were randomly divided into 4 groups based on the amount of freeze-dried GABA-producer added to the basal diet as follows: i 0 mg/kg, ii 25 mg/kg, iii 50 mg/kg, and iv 100 mg/kg. All hens were subjected to heat-stress treatment through maintaining the temperature and the relative humidity at 28.83±3.85°C and 37% to 53.9%, respectively. During the experiment, laying rate, egg weight and feed intake of hens were recorded daily. At the 30th and 60th day after the start of the experiment, biochemical parameters, enzyme activity and immune activity in serum were measured. Egg production, average egg weight, average daily feed intake, feed conversion ratio and percentage of speckled egg, soft shell egg and misshaped egg were significantly improved (p<0.05 by the increasing supplementation of the dietary GABA-producer. Shape index, eggshell thickness, strength and weight were increased linearly with increasing GABA-producer supplementation. The level of calcium, phosphorus, glucose, total protein and albumin in serum of the hens fed GABA-producing strain supplemented diet was significantly higher (p<0.05 than that of the hens fed the basal diet, whereas cholesterol level was decreased. Compared with the basal diet, GABA-producer strain supplementation increased serum level of glutathione peroxidase (p = 0.009 and superoxide dismutase. In conclusion, GABA-producer played an important role in alleviating heat-stress, the isolated GABA-producer strain might be a potential natural and safe probiotic to use to

Construction of acetoin high-producing Bacillus subtilis strain

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Yanjun Tian

2016-07-01

Full Text Available This paper describes the construction and selection of a high-producing mutant, Bacillus subtilis HB-32, with enhanced acetoin yield and productivity. The mutant was obtained by the protoplast fusion of a Bacillus subtilis mutant TH-49 (Val− producing acetoin and Bacillus licheniformis AD-30 producing α-acetolactate decarboxylase, with the fusogen polyethylene glycol and after the regeneration and selection, etc. of the fusant. The acetoin production reached 49.64 g/L, which is an increase of 61.8% compared to that of B. subtilis strain TH-49. Random amplified polymorphic DNA analysis was performed to determine the mutagenic and protoplast fusion effects and the genomic changes in the acetoin high-producing strain compared to the parent strains at the molecular level. The constructed strain was shown to be promising for large-scale acetoin production. Future studies should focus on the application of the mutant strain in practice.

Deletion of a Chitin Synthase Gene in a Citric Acid Producing Strain of Aspergillus niger

Energy Technology Data Exchange (ETDEWEB)

Rinker, Torri E.; Baker, Scott E.

2007-01-29

Citric acid production by the filamentous fungus Aspergillus niger is carried out in a process that causes the organism to drastically alter its morphology. This altered morphology includes hyphal swelling and highly limited polar growth resulting in clumps of swollen cells that eventually aggregate into pellets of approximately 100 microns in diameter. In this pelleted form, A. niger has increased citric acid production as compared to growth in filamentous form. Chitin is a crucial component of the cell wall of filamentous fungi. Alterations in the deposition or production of chitin may have profound effects on the morphology of the organism. In order to study the role of chitin synthesis in pellet formation we have deleted a chitin synthase gene (csmA) in Aspergillus niger strain ATCC 11414 using a PCR based deletion construct. This class of chitin synthases is only found in filamentous fungi and is not present in yeasts. The csmA genes contain a myosin motor domain at the N-terminus and a chitin synthesis domain at the C-terminus. They are believed to contribute to the specialized polar growth observed in filamentous fungi that is lacking in yeasts. The csmA deletion strain (csmAΔ) was subjected to minimal media with and without osmotic stabilizers as well as tested in citric acid production media. Without osmotic stabilizers, the mutant germlings were abnormally swollen, primarily in the subapical regions, and contained large vacuoles. However, this swelling is ultimately not inhibitory to growth as the germlings are able to recover and undergo polar growth. Colony formation was largely unaffected in the absence of osmotic stabilizers. In citric acid production media csmAΔ was observed to have a 2.5 fold increase in citric acid production. The controlled expression of this class of chitin synthases may be useful for improving production of organic acids in filamentous fungi.

Enhanced L-(+)-lactic acid production by an adapted strain of Rhizopus oryzae using corncob hydrolysate

DEFF Research Database (Denmark)

Bai, Dongmei; Li, S.Z.; Liu, Z.L.

2008-01-01

-added production of a variety of bioproducts. Lactic acid can be used as a precursor for poly-lactic acid production. Although current industrial lactic acid is produced by lactic acid bacteria using enriched medium, production by Rhizopus oryzae is preferred due to its exclusive formation of the......-isomer and a simple nutrition requirement by the fungus. Production of-L-(+)-lactic acid by R. oryzae using xylose has been reported; however, its yield and conversion rate are poor compared with that of using glucose. In this study, we report an adapted R. oryzae strain HZS6 that significantly improved efficiency...... of substrate utilization and enhanced production of L-(+)-lactic acid from corncob hydrolysate. It increased L-(+)-lactic acid final concentration, yield, and volumetric productivity more than twofold compared with its parental strain. The optimized growth and fermentation conditions for Strain HZS6 were...

Cyanobacteria as efficient producers of mycosporine-like amino acids.

Science.gov (United States)

Jain, Shikha; Prajapat, Ganshyam; Abrar, Mustari; Ledwani, Lalita; Singh, Anoop; Agrawal, Akhil

2017-09-01

Mycosporine-like amino acids are the most common group of transparent ultraviolet radiation absorbing intracellular secondary metabolites. These molecules absorb light in the range of ultraviolet-A and -B with a maximum absorbance between 310 and 362 nm. Cyanobacteria might have faced the most deleterious ultraviolet radiation, which leads to an evolution of ultraviolet protecting mycosporine-like amino acids for efficient selection in the environment. In the last 30 years, scientists have investigated various cyanobacteria for novel mycosporine-like amino acids, applying different induction techniques. This review organizes all the cyanobacterial groups that produce various mycosporine-like amino acids. We found out that cyanobacteria belonging to orders Synechococcales, Chroococcales, Oscillatoriales, and Nostocales are frequently studied for the presence of mycosporine-like amino acids, while orders Gloeobacterales, Spirulinales, Pleurocapsales, and Chroococcidiopsidales are still need to be investigated. Nostoc and Anabaena strains are major studied genus for the mycosporine-like amino acids production. Hence, this review will give further insight to the readers about potential mycosporine-like amino acid producing cyanobacterial groups in future investigations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Isolation and characterization of fatty acid methyl ester (FAME)-producing Streptomyces sp. S161 from sheep (Ovis aries) faeces.

Science.gov (United States)

Lu, Y; Wang, J; Deng, Z; Wu, H; Deng, Q; Tan, H; Cao, L

2013-09-01

An actinomycete producing oil-like mixtures was isolated and characterized. The strain was isolated from sheep faeces and identified as Streptomyces sp. S161 based on 16S rRNA gene sequence analysis. The strain showed cellulase and xylanase activities. The (1) H nuclear magnetic resonance (NMR) spectra of the mixtures showed that the mixtures were composed of fatty acid methyl esters (52·5), triglycerides (13·7) and monoglycerides (9·1) (mol.%). Based on the gas chromatography-mass spectrometry (GC-MS) analysis, the fatty acid methyl esters were mainly composed of C14-C16 long-chain fatty acids. The results indicated that Streptomyces sp. S161 could produce fatty acid methyl esters (FAME) directly from starch. To our knowledge, this is the first isolated strain that can produce biodiesel (FAME) directly from starch. © 2013 The Society for Applied Microbiology.

An application in cheddar cheese manufacture for a strain of Lactococcus lactis producing a novel broad-spectrum bacteriocin, lacticin 3147.

Science.gov (United States)

Ryan, M P; Rea, M C; Hill, C; Ross, R P

1996-01-01

Lactococcus lactis DPC3147, a strain isolated from an Irish kefir grain, produces a bacteriocin with a broad spectrum of inhibition. The bacteriocin produced is heat stable, particularly at a low pH, and inhibits nisin-producing (Nip+) lactococci. On the basis of the observation that the nisin structural gene (nisA) does not hybridize to DPC3147 genomic DNA, the bacteriocin produced was considered novel and designated lacticin 3147. The genetic determinants which encode lacticin 3147 are contained on a 63-kb plasmid, which was conjugally mobilized to a commercial cheese starter, L. lactis subsp. cremoris DPC4268. The resultant transconjugant, DPC4275, both produces and is immune to lacticin 3147. The ability of lacticin 3147-producing lactococci to perform as cheddar cheese starters was subsequently investigated in cheesemaking trials. Bacteriocin-producing starters (which included the transconjugant strain DPC4275) produced acid at rates similar to those of commercial strains. The level of lacticin 3147 produced in cheese remained constant over 6 months of ripening and correlated with a significant reduction in the levels of nonstarter lactic acid bacteria. Such results suggest that these starters provide a means of controlling developing microflora in ripened fermented products. PMID:8593062

Effect of γ-Aminobutyric Acid-producing Lactobacillus Strain on Laying Performance, Egg Quality and Serum Enzyme Activity in Hy-Line Brown Hens under Heat Stress.

Science.gov (United States)

Zhu, Y Z; Cheng, J L; Ren, M; Yin, L; Piao, X S

2015-07-01

Heat-stress remains a costly issue for animal production, especially for poultry as they lack sweat glands, and alleviating heat-stress is necessary for ensuring animal production in hot environment. A high γ-aminobutyric acid (GABA)-producer Lactobacillus strain was used to investigate the effect of dietary GABA-producer on laying performance and egg quality in heat-stressed Hy-line brown hens. Hy-Line brown hens (n = 1,164) at 280 days of age were randomly divided into 4 groups based on the amount of freeze-dried GABA-producer added to the basal diet as follows: i) 0 mg/kg, ii) 25 mg/kg, iii) 50 mg/kg, and iv) 100 mg/kg. All hens were subjected to heat-stress treatment through maintaining the temperature and the relative humidity at 28.83±3.85°C and 37% to 53.9%, respectively. During the experiment, laying rate, egg weight and feed intake of hens were recorded daily. At the 30th and 60th day after the start of the experiment, biochemical parameters, enzyme activity and immune activity in serum were measured. Egg production, average egg weight, average daily feed intake, feed conversion ratio and percentage of speckled egg, soft shell egg and misshaped egg were significantly improved (pGABA-producer. Shape index, eggshell thickness, strength and weight were increased linearly with increasing GABA-producer supplementation. The level of calcium, phosphorus, glucose, total protein and albumin in serum of the hens fed GABA-producing strain supplemented diet was significantly higher (plevel was decreased. Compared with the basal diet, GABA-producer strain supplementation increased serum level of glutathione peroxidase (p = 0.009) and superoxide dismutase. In conclusion, GABA-producer played an important role in alleviating heat-stress, the isolated GABA-producer strain might be a potential natural and safe probiotic to use to improve laying performance and egg quality in heat-stressed hens.

Succinic acid production from xylose mother liquor by recombinant Escherichia coli strain.

Science.gov (United States)

Wang, Honghui; Pan, Jiachuan; Wang, Jing; Wang, Nan; Zhang, Jie; Li, Qiang; Wang, Dan; Zhou, Xiaohua

2014-11-02

Succinic acid (1,4-butanedioic acid) is identified as one of important building-block chemicals. Xylose mother liquor is an abundant industrial residue in xylitol biorefining industry. In this study, xylose mother liquor was utilized to produce succinic acid by recombinant Escherichia coli strain SD121, and the response surface methodology was used to optimize the fermentation media. The optimal conditions of succinic acid fermentation were as follows: 82.62 g L -1 total initial sugars, 42.27 g L -1 MgCO 3 and 17.84 g L -1 yeast extract. The maximum production of succinic acid was 52.09 ± 0.21 g L -1 after 84 h with a yield of 0.63 ± 0.03 g g -1 total sugar, approaching the predicted value (53.18 g L -1 ). It was 1.78-fold of the production of that obtained with the basic medium. This was the first report on succinic acid production from xylose mother liquor by recombinant E. coli strains with media optimization using response surface methodology. This work suggested that the xylose mother liquor could be an alternative substrate for the economical production of succinic acid by recombinant E. coli strains.

Utilization of Vinegar for Isolation of Cellulose Producing Acetic Acid Bacteria

International Nuclear Information System (INIS)

Aydin, Y. Andelib; Aksoy, Nuran Deveci

2010-01-01

Wastes of traditionally fermented Turkish vinegar were used in the isolation of cellulose producing acetic acid bacteria. Waste material was pre-enriched in Hestrin-Schramm medium and microorganisms were isolated by plating dilution series on HS agar plates The isolated strains were subjected to elaborate biochemical and physiological tests for identification. Test results were compared to those of reference strains Gluconacetobacter xylinus DSM 46604, Gluconacetobacter hansenii DSM 5602 and Gluconacetobacter liquefaciens DSM 5603. Seventeen strains, out of which only three were found to secrete the exopolysaccharide cellulose. The highest cellulose yield was recorded as 0.263±0.02 g cellulose L -1 for the strain AS14 which resembled Gluconacetobacter hansenii in terms of biochemical tests.

Preliminary Evaluation of Glyceric Acid-producing Ability of Acidomonas methanolica NBRC104435 from Glycerol Containing Methanol.

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Sato, Shun; Kitamoto, Dai; Habe, Hiroshi

2017-06-01

Some acetic acid bacteria produce large amounts of glyceric acid (GA) from glycerol in culture broth. However, methanol, which is a major contaminant of raw glycerol derived from the biodiesel fuel industry, sharply decreases cell growth and GA production [AMB Express, 3, 20, 2013]. Thus, we evaluated the methylotrophic acetic acid bacterium Acidomonas methanolica NBRC104435 for its ability to produce GA from glycerol containing methanol. This strain accumulated GA in its culture broth when 1-3 wt% glycerol was available as a carbon source. We observed improved cell growth and GA accumulation when 1 vol% methanol was added to the 3-5 wt% glycerol medium. The maximum concentration of GA was 12.8 g/L in medium containing 3 wt% glycerol plus 1 vol% methanol. In addition, the enantiomeric excess (ee) of the GA produced was revealed to be 44%, indicating that this strain converted glycerol to d-GA with a lower enantioselectivity than other acetic acid bacteria, which had 70-99% ee.

Isolation of a yeast strain able to produce a polygalacturonase with maceration activity of cassava roots

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María Alicia Martos

2013-06-01

Full Text Available The objective of the present study was the isolation of a yeast strain, from citrus fruit peels, able to produce a polygalacturonase by submerged fermentation with maceration activity of raw cassava roots. Among 160 yeast strains isolated from citrus peels, one strain exhibited the strongest pectinolytic activity. This yeast was identified as Wickerhamomyces anomalus by 5.8S-ITS RFLP analysis and confirmed by amplification of the nucleotide sequence. The yeast produced a polygalacturonase (PG in Erlenmeyer shake flasks containing YNB, glucose, and citrus pectin. PG synthesis occurred during exponential growth phase, reaching 51 UE.mL-1 after 8 hours of fermentation. A growth yield (Yx/s of 0.43 gram of cell dry weight per gram of glucose consumed was obtained, and a maximal specific growth rate (µm of 0.346 h-1 was calculated. The microorganism was unable to assimilate sucrose, galacturonic acid, polygalacturonic acid, or citrus pectin, but it required glucose as carbon and energy source and polygalacturonic acid or citrus pectin as inducers of enzyme synthesis. The crude enzymatic extract of Wickerhamomyces anomalus showed macerating activity of raw cassava. This property is very important in the production of dehydrated mashed cassava, a product of regional interest in the province of Misiones, Argentina.

Antimicrobial properties of Pseudomonas strains producing the antibiotic mupirocin.

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Matthijs, Sandra; Vander Wauven, Corinne; Cornu, Bertrand; Ye, Lumeng; Cornelis, Pierre; Thomas, Christopher M; Ongena, Marc

2014-10-01

Mupirocin is a polyketide antibiotic with broad antibacterial activity. It was isolated and characterized about 40 years ago from Pseudomonas fluorescens NCIMB 10586. To study the phylogenetic distribution of mupirocin producing strains in the genus Pseudomonas a large collection of Pseudomonas strains of worldwide origin, consisting of 117 Pseudomonas type strains and 461 strains isolated from different biological origins, was screened by PCR for the mmpD gene of the mupirocin gene cluster. Five mmpD(+) strains from different geographic and biological origin were identified. They all produced mupirocin and were strongly antagonistic against Staphylococcus aureus. Phylogenetic analysis showed that mupirocin production is limited to a single species. Inactivation of mupirocin production leads to complete loss of in vitro antagonism against S. aureus, except on certain iron-reduced media where the siderophore pyoverdine is responsible for the in vitro antagonism of a mupirocin-negative mutant. In addition to mupirocin some of the strains produced lipopeptides of the massetolide group. These lipopeptides do not play a role in the observed in vitro antagonism of the mupirocin producing strains against S. aureus. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Identification and characterization of thermotolerant acetic acid bacteria strains isolated from coconut water vinegar in Sri Lanka.

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Perumpuli, P A B N; Watanabe, Taisuke; Toyama, Hirohide

2014-01-01

From the pellicle formed on top of brewing coconut water vinegar in Sri Lanka, three Acetobacter strains (SL13E-2, SL13E-3, and SL13E-4) that grow at 42 °C and four Gluconobacter strains (SL13-5, SL13-6, SL13-7, and SL13-8) grow at 37 °C were identified as Acetobacter pasteurianus and Gluconobacter frateurii, respectively. Acetic acid production by the isolated Acetobacter strains was examined. All three strains gave 4% acetic acid from 6% initial ethanol at 37 °C, and 2.5% acetic acid from 4% initial ethanol at 40 °C. Compared with the two other strains, SL13E-4 showed both slower growth and slower acetic acid production. As well as the thermotolerant SKU1108 strain, the activities of the alcohol dehydrogenase and the aldehyde dehydrogenase of SL13E-2 and SL13E-4 were more stable than those of the mesophilic strain. The isolated strains were used to produce coconut water vinegar at higher temperatures than typically used for vinegar production.

Variable characteristics of bacteriocin-producing Streptococcus salivarius strains isolated from Malaysian subjects.

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Abdelahhad Barbour

Full Text Available BACKGROUND: Salivaricins are bacteriocins produced by Streptococcus salivarius, some strains of which can have significant probiotic effects. S. salivarius strains were isolated from Malaysian subjects showing variable antimicrobial activity, metabolic profile, antibiotic susceptibility and lantibiotic production. METHODOLOGY/PRINCIPAL FINDINGS: In this study we report new S. salivarius strains isolated from Malaysian subjects with potential as probiotics. Safety assessment of these strains included their antibiotic susceptibility and metabolic profiles. Genome sequencing using Illumina's MiSeq system was performed for both strains NU10 and YU10 and demonstrating the absence of any known streptococcal virulence determinants indicating that these strains are safe for subsequent use as probiotics. Strain NU10 was found to harbour genes encoding salivaricins A and 9 while strain YU10 was shown to harbour genes encoding salivaricins A3, G32, streptin and slnA1 lantibiotic-like protein. Strain GT2 was shown to harbour genes encoding a large non-lantibiotic bacteriocin (salivaricin-MPS. A new medium for maximum biomass production buffered with 2-(N-morpholinoethanesulfonic acid (MES was developed and showed better biomass accumulation compared with other commercial media. Furthermore, we extracted and purified salivaricin 9 (by strain NU10 and salivaricin G32 (by strain YU10 from S. salivarius cells grown aerobically in this medium. In addition to bacteriocin production, S. salivarius strains produced levan-sucrase which was detected by a specific ESI-LC-MS/MS method which indicates additional health benefits from the developed strains. CONCLUSION: The current study established the bacteriocin, levan-sucrase production and basic safety features of S. salivarius strains isolated from healthy Malaysian subjects demonstrating their potential for use as probiotics. A new bacteriocin-production medium was developed with potential scale up application for

Production of L-lactic acid from metabolically engineered strain of Enterobacter aerogenes ATCC 29007.

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Thapa, Laxmi Prasad; Lee, Sang Jun; Park, Chulhwan; Kim, Seung Wook

2017-07-01

In this study, L-lactic acid production was investigated from metabolically engineered strain of E. aerogenes ATCC 29007. The engineered strain E. aerogenes SUMI01 (Δpta) was generated by the deletion of phosphate acetyltransferase (pta) gene from the chromosome of E. aerogenes ATCC 29007 and deletion was confirmed by colony PCR. Under the optimized fermentation conditions, at 37°C and pH 6 for 84h, the L-lactic acid produced by engineered strain E. aerogenes SUMI01 (Δpta) in flask fermentation using 100g/L mannitol as the carbon source was 40.05g/L as compared to that of the wild type counterpart 20.70g/L. At the end of the batch fermentation in bioreactor the production of L-lactic acid reached to 46.02g/L and yield was 0.41g/g by utilizing 112.32g/L mannitol. This is the first report regarding the production of L-lactic acid from Enterobacter species. We believe that this result may provide valuable guidelines for further engineering Enterobacter strain for the improvement of L-lactic acid production. Copyright © 2017 Elsevier Inc. All rights reserved.

Competitive Dominance by a Bacteriocin-Producing Vibrio harveyi Strain.

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Hoyt, P R; Sizemore, R K

1982-09-01

Vibrio (Beneckea) harveyi, a bioluminescent marine bacterium, has been shown to produce a bacteriocin-like substance the production of which is mediated by a plasmid. This substance is assumed to be proteinaceous because of its sensitivity to certain proteolytic enzymes. It is stable at low temperatures and can be concentrated by ammonium sulfate precipitation or negative-pressure dialysis. The molecular weight of the bacteriocin was determined to be 2.4 x 10 by molecular exclusion chromatography. Competition experiments indicated that bacteriocin-producing strains predominated over cured variants of the same strain in broth culture experiments. We studied several environmental parameters (pH, salinity, temperature, nutrient concentration) to determine their effects on the competitive advantage bestowed on a bacteriocin-producing strain. Under simulated free-living conditions, no competitive advantage attributable to bacteriocin production was observed. In a simulated enteric habitat, a bacteriocin-producing strain showed dramatic (>90%) inhibition of the sensitive strain within 24 h.

Effects of some organic pollutants on the exopolysaccharides (EPSs) produced by some Pseudomonas spp. strains

International Nuclear Information System (INIS)

Onbasli, Dilsad; Aslim, Belma

2009-01-01

In this study, isolation and characterization of exopolysaccharides produced by Pseudomonas aeruginosa B1, P. fluorescens B5, P. stutzeri B11 and P. putida B15 which had been seen to produce exopolymers of potential interest in biotechnological applications were examined. To initiate the observation of the organic pollutants-polymer interactions, the yield and properties of their extracellular polysaccharide were researched. The exopolysaccharide production by these strains during growth in nutrient broth medium (control) was 41-75 mg L -1 . Also, P. aeruginosa B1, P. fluorescens B5, P. stutzeri B11 and P. putida B15 had exhibited high production of EPSs in presence of various organic pollutants (2,4-D, benzene, BTX and gasoline, respectively) in mineral salt medium (MSM) as a sole carbon source. EPS production by the 4 strains ranged from 40 mg L -1 to 8 mg L -1 . Monosaccharide composition of EPS produced by these cultures were analyzed by HPLC. Results indicated that EPSs of strains contained neutral sugars and acetylated amino sugars. The neutral sugars in the EPS were mainly composed of glucose, arabinose, glycerol, ribose. The presence of galactronic acid, N-acetyl-D-galactosamin and N-acetyl-D-glucosamine indicated the acidic nature of the polysaccharide. Glycerol was the basic structural unit of EPS produced by the strains except P. stutzeri B11 (MSM with 1% BTX). Strain B1 (in NB medium) was found to be composed of neutral sugars (100%) while strain B1 [in MSM medium with 0.2% (v/v) 2.4-D] contained neutral sugars (70.0%), acetylated amino sugars (30.0%). Also, EPS content of strain B5 (in the NB medium) was neutral sugars (99.8%), acetylated amino sugars (0.2%) while the strain B5 [in MSM medium containing the 1% (v/v) benzene] was found to contain neutral sugars (99.9%), acetylated amino sugars (0.1%). However, EPS monomer composition by strain B11 was detected as neutral sugars (99.77%), acetylated amino sugars (0.23%) in NB medium while the strain B11

Description of two Enterococcus strains isolated from traditional Peruvian artisanal-produced cheeses with a bacteriocin-like inhibitory activity

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Aguilar Galvez A.

2009-01-01

Full Text Available The aim of this work was to isolate and to characterize strains of lactic acid bacteria (LAB with bacteriocin-like inhibitory activity from 27 traditional cheeses artisanal-produced obtained from different Peruvian regions. Twenty Gram+ and catalasenegative strains among 2,277 isolates exhibited bacteriocin-like inhibitory activity against Listeria monocytogenes CWBIB2232 as target strain. No change in inhibitory activity was observed after organic acid neutralization and treatment with catalase of the cell-free supernatant (CFS. The proteinic nature of the antimicrobial activity was confirmed for the twenty LAB strains by proteolytic digestion of the CFS. Two strains, CWBI-B1431 and CWBI-B1430, with the best antimicrobial activity were selected for further researches. These strains were taxonomically identified by phenotypic and genotypic analyses as Enterococcus mundtii (CWBI-B1431 and Enterococcus faecium (CWBI-B1430. The two strains were sensitive to vancomycin (MIC 2 μg.ml-1 and showed absence of haemolysis.

Organic metabolites produced by Vibrio parahaemolyticus strain ...

African Journals Online (AJOL)

Identification and action of several antibacterial metabolites produced by a fish pathogen Vibrio parahaemolyticus strain An3 from marine ecosystem of Goa has been demonstrated. Antibacterial activity of the crude cell extract of the test bacterium has been evaluated against indicator pathogenic bacterial strains such as ...

ISOLATION AND IDENTIFICATION OF LACTIC ACID PRODUCING BACTERIA FROM CAMEL MILK

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Toqeer Ahmad, Rashida Kanwal, Izhar Hussain Athar1, Najam Ayub

2002-03-01

Full Text Available Lactic acid bacteria (LAB were isolated from camel milk by culturing the camel milk on specific media and pure culture was obtained by sub culturing. Purification of culture was confirmed by Gram's staining and identified by different bio-chemical tests. Camel milk contains lactic acid producing bacteria including Strpptococci such as S. cremoris and S. lactis and Lactobacilli such as L. acidophilus L. acidophilus grows more rapidly in camel milk than others as its growth is supported by camel milk. A variety of food can be preserved by lactic acid fermentation, so starter culture was prepared from strains which were isolated from camel milk. Camel and buffalo's milk cheese was prepared by using starter culture. The strains isolated from camel milk were best for acid production and can coagulate the milk in less lime. Camel milk cheese was prepared and compared with buffalo's milk cheese. It is concluded that cheese can be prepared successfully from camel milk and better results can be obtained by coagulating milk with starter culture.

Effect of Supplementation with n-3 Fatty Acids Extracted from Microalgae on Inflammation Biomarkers from Two Different Strains of Mice

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L. E. Gutiérrez-Pliego

2018-01-01

Full Text Available Background. Diabetes mellitus is considered a chronic noncommunicable disease in which inflammation plays a main role in the progression of the disease and it is known that n-3 fatty acids have anti-inflammatory properties. One of the most recent approaches is the study of the fatty acids of microalgae as a substitute for fish oil and a source rich in fatty acids EPA and DHA. Objective. To analyze the effect of supplementation with n-3 fatty acids extracted from microalgae on the inflammatory markers from two different strains of mice. Methods. Mice of two strains, db/db and CD1, were supplemented with n-3 fatty acids extracted from microalgae in lyophilized form and added to food; the experiment was carried out from week 8 to 16 of life. Flow cytometry was performed to determine the percentage of TCD4+ cells producing Th1 and Th2 cytokines. Results. Supplementation with microalgae fatty acids decreased the percentage of TCD4+ cells producing IFN-γ and TNF-α and increased the ones producing IL-17A and IL-12 in both strains; on the other hand, supplementation decreased percentage of TCD4+ cells producing IL-4 and increased the ones producing TGF-β. Conclusions. Microalgae n-3 fatty acids could be a useful tool in the treatment of diabetes as well as in the prevention of the appearance of health complications caused by inflammatory states.

Symbiotic effectiveness of acid-tolerant Bradyrhizobium strains with ...

African Journals Online (AJOL)

Symbiotic effectiveness of acid-tolerant Bradyrhizobium strains with soybean in low pH soil. C Appunu, B Dhar. Abstract. Eight acid tolerant strains of Bradyrhizobium isolated from soybean plants grown on acid soils in Madhya Pradesh, India, were examined for their ability to survive in soil and YEMB at low pH levels. All the ...

Complete Genome Sequence of the Gamma-Aminobutyric Acid-Producing Strain Streptococcus thermophilus APC151.

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Linares, Daniel M; Arboleya, Silvia; Ross, R Paul; Stanton, Catherine

2017-04-27

Here is presented the whole-genome sequence of Streptococcus thermophilus APC151, isolated from a marine fish. This bacterium produces gamma-aminobutyric acid (GABA) in high yields and is biotechnologically suitable to produce naturally GABA-enriched biofunctional yogurt. Its complete genome comprises 2,097 genes and 1,839,134 nucleotides, with an average G+C content of 39.1%. Copyright © 2017 Linares et al.

Isolation and Identification of L-asparaginase producing Erwinia strains which isolated from Potato Farms

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Arastoo Badoei-Dalfard

2016-09-01

Full Text Available Introduction: L-Asparaginase can be effectively used for the treatment of lymphoblastic leukemia. The rapid growth of cancer cells are needed for L-asparagine abundant storage. L-asparaginase catalyzes the hydrolysis of L-asparagine into L-aspartic acid and ammonia. The purpose of this study was to isolate and identify the L-asparaginase producing Erwinia strains from the potato farms of Jiroft. Materials and methods: Pectolytic Erwinia species isolated from crumbling potato in M9 medium. The desired L-asparaginase producing bacteria were isolated based on the color changes. Biochemical-microbial and the plant pathogenicity tests of these strains were also investigated with potato and geranium. The L-asparaginase production and molecular detection of these Erwinia strains were also investigated. Results: In this study, L-asparaginase producing Erwinia was isolated on the CVP and M9 mediums. The inoculation of Erwinia strains on the potato and geranium plants showed that Er8 and Er11 species have the ability to cause plant pathogenicity. Results showed that the maximum pathogenicity of Er8 and Er11 was observed after 48 and 15 h of inoculation in potato and geranium plants, respectively. 16S rDNA sequencing and phylogenetic analyses exhibited that Er8 and Er11 strains were similar to Erwinia chrysanthemi with 98% homology. Discussion and conclusion: Because of several applications of the Erwinia L-asparaginase in various fields, isolated Erwinia and their L-asparaginase can be suitable for applied utilization.

Key volatile aroma compounds of lactic acid fermented malt based beverages - impact of lactic acid bacteria strains.

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Nsogning Dongmo, Sorelle; Sacher, Bertram; Kollmannsberger, Hubert; Becker, Thomas

2017-08-15

This study aims to define the aroma composition and key aroma compounds of barley malt wort beverages produced from fermentation using six lactic acid bacteria (LAB) strains. Gas chromatography mass spectrometry-olfactometry and flame ionization detection was employed; key aroma compounds were determined by means of aroma extract dilution analysis. Fifty-six detected volatile compounds were similar among beverages. However, significant differences were observed in the concentration of individual compounds. Key aroma compounds (flavor dilution (FD) factors ≥16) were β-damascenone, furaneol, phenylacetic acid, 2-phenylethanol, 4-vinylguaiacol, sotolon, methional, vanillin, acetic acid, nor-furaneol, guaiacol and ethyl 2-methylbutanoate. Furthermore, acetaldehyde had the greatest odor activity value of up to 4266. Sensory analyses revealed large differences in the flavor profile. Beverage from L. plantarum Lp. 758 showed the highest FD factors in key aroma compounds and was correlated to fruity flavors. Therefore, we suggest that suitable LAB strain selection may improve the flavor of malt based beverages. Copyright © 2017 Elsevier Ltd. All rights reserved.

Deoxyribonucleic acid-deficient strains of Candida albicans.

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Olaiya, A F; Steed, J R; Sogin, S J

1980-03-01

We analyzed a series of germ tube-negative variants isolated from Candida albicans 3153A for deoxyribonucleic acid content. As analyzed by flow microfluorometry, the deoxyribonucleic acid level in these variant strains was 50% of that of the parental strain and equivalent to that of haploid Saccharomyces cerevisiae. This finding was confirmed by comparison of survival rates when exposed to the mutagens ultraviolet light, ethyl methane sulfonate, and methyl methane sulfonate. The diameter of the variant cells as compared to the diameter of the parental 3153A strain showed a relationship similar to that of the diameters of haploid versus diploid S. cerevisiae. These results indicate that those strains may be representative of the imperfect stage of C. albicans.

Development of an efficient fungal DNA extraction method to be used in random amplified polymorphic DNA-PCR analysis to differentiate cyclopiazonic acid mold producers.

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Sánchez, Beatriz; Rodríguez, Mar; Casado, Eva M; Martín, Alberto; Córdoba, Juan J

2008-12-01

A variety of previously established mechanical and chemical treatments to achieve fungal cell lysis combined with a semiautomatic system operated by a vacuum pump were tested to obtain DNA extract to be directly used in randomly amplified polymorphic DNA (RAPD)-PCR to differentiate cyclopiazonic acid-producing and -nonproducing mold strains. A DNA extraction method that includes digestion with proteinase K and lyticase prior to using a mortar and pestle grinding and a semiautomatic vacuum system yielded DNA of high quality in all the fungal strains and species tested, at concentrations ranging from 17 to 89 ng/microl in 150 microl of the final DNA extract. Two microliters of DNA extracted with this method was directly used for RAPD-PCR using primer (GACA)4. Reproducible RAPD fingerprints showing high differences between producer and nonproducer strains were observed. These differences in the RAPD patterns did not differentiate all the strains tested in clusters by cyclopiazonic acid production but may be very useful to distinguish cyclopiazonic acid producer strains from nonproducer strains by a simple RAPD analysis. Thus, the DNA extracts obtained could be used directly without previous purification and quantification for RAPD analysis to differentiate cyclopiazonic acid producer from nonproducer mold strains. This combined analysis could be adaptable to other toxigenic fungal species to enable differentiation of toxigenic and non-toxigenic molds, a procedure of great interest in food safety.

DOMESTIC BUTANOL-PRODUCING STRAINS OF THE Clostridium GENUS

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O. O. Tigunova

2017-02-01

Full Text Available The aim of the work was to summarize the results of own research concerning obtaining butanol producing strains of Clostridium genus, to identify them by physiological, morphological and genetic methods. Further study of characteristics and biological features of the strains, and various approaches in biotechnological process of butanol production are discussed. The work includes methods to increase butanol accumulation by producer strains. Perspectives of using chemical mutagenesis in Clostridia as a method of increasing butanol production are considered. The feasibility of using non-food raw material as a substrate for fermentation is discussed. Different methods of pretreatment and their impact on the accumulation of butanol in the liquid medium are compared. Butanol accumulation is shown to increase significantly if the synthesis precursors are added as components of enzymatic medium, and the “reverse bard” is used to reduce waste production without affecting the level of butanol synthesis. The problem of conservation of producing strains is given, and protective medium for microorganisms during the freeze-drying is defined.

An efficient process for lactic acid production from wheat straw by a newly isolated Bacillus coagulans strain IPE22.

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Zhang, Yuming; Chen, Xiangrong; Luo, Jianquan; Qi, Benkun; Wan, Yinhua

2014-04-01

A thermophilic lactic acid (LA) producer was isolated and identified as Bacillus coagulans strain IPE22. The strain showed remarkable capability to ferment pentose, hexose and cellobiose, and was also resistant to inhibitors from lignocellulosic hydrolysates. Based on the strain's promising features, an efficient process was developed to produce LA from wheat straw. The process consisted of biomass pretreatment by dilute sulfuric acid and subsequent SSCF (simultaneous saccharification and co-fermentation), while the operations of solid-liquid separation and detoxification were avoided. Using this process, 46.12 g LA could be produced from 100g dry wheat straw with a supplement of 10 g/L corn steep liquid powder at the cellulase loading of 20 FPU (filter paper activity units)/g cellulose. The process by B. coagulans IPE22 provides an economical route to produce LA from lignocellulose. Copyright © 2014 Elsevier Ltd. All rights reserved.

Production of lactic acid from sucrose: strain selection, fermentation, and kinetic modeling.

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Lunelli, Betânia H; Andrade, Rafael R; Atala, Daniel I P; Wolf Maciel, Maria Regina; Maugeri Filho, Francisco; Maciel Filho, Rubens

2010-05-01

Lactic acid is an important product arising from the anaerobic fermentation of sugars. It is used in the pharmaceutical, cosmetic, chemical, and food industries as well as for biodegradable polymer and green solvent production. In this work, several bacterial strains were isolated from industrial ethanol fermentation, and the most efficient strain for lactic acid production was selected. The fermentation was conducted in a batch system under anaerobic conditions for 50 h at a temperature of 34 degrees C, a pH value of 5.0, and an initial sucrose concentration of 12 g/L using diluted sugarcane molasses. Throughout the process, pulses of molasses were added in order to avoid the cell growth inhibition due to high sugar concentration as well as increased lactic acid concentrations. At the end of the fermentation, about 90% of sucrose was consumed to produce lactic acid and cells. A kinetic model has been developed to simulate the batch lactic acid fermentation results. The data obtained from the fermentation were used for determining the kinetic parameters of the model. The developed model for lactic acid production, growth cell, and sugar consumption simulates the experimental data well.

Optimization of lactic acid production from glucose using geobacillus stearothermophilus strain 15

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Kunasundari, Balakrishnan; Naresh, Sandrasekaran; Safie, Mohammad Farhan Mohd

2017-09-01

This study investigated the conversion efficiency of glucose to lactic acid by Geobacillus stearothermophilus strain 15. Six parameters (temperature, pH, incubation time, agitation speed, carbon and nitrogen concentrations) were screened to identify the most significant factors in affecting lactic acid production using glucose. Three most significant factors (temperature, pH and incubation time) were further optimized in this experiment to determine the optimal production of lactic acid. Numerical optimization gave the point prediction of lactic acid concentration produced at 9.95 g/L with the desirability of 0.979 at 40°C, pH 8.5, 24 h, 100 rpm with 5% glucose and 3% yeast extract.

Enterobacter sp. LU1 as a novel succinic acid producer - co-utilization of glycerol and lactose.

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Podleśny, Marcin; Jarocki, Piotr; Wyrostek, Jakub; Czernecki, Tomasz; Kucharska, Jagoda; Nowak, Anna; Targoński, Zdzisław

2017-03-01

Succinic acid is an important C4-building chemical platform for many applications. A novel succinic acid-producing bacterial strain was isolated from goat rumen. Phylogenetic analysis based on the 16S rRNA sequence and physiological analysis indicated that the strain belongs to the genus Enterobacter. This is the first report of a wild bacterial strain from the genus Enterobacter that is capable of efficient succinic acid production. Co-fermentation of glycerol and lactose significantly improved glycerol utilization under anaerobic conditions, debottlenecking the utilization pathway of this valuable biodiesel waste product. Succinic acid production reached 35 g l -1 when Enterobacter sp. LU1 was cultured in medium containing 50 g l -1 of glycerol and 25 g l -1 of lactose as carbon sources. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Ultraviolet light-induced mutants of Streptococcus lactis subspecies diacetylactis with enhanced acid- or flavor-producing abilities

International Nuclear Information System (INIS)

Kuila, R.K.; Ranganathan, B.

1978-01-01

A strain of Streptococcus lactis subspecies diacetylactis S 1 isolated from fresh milk was exposed to 7200 ergs/mm 2 of ultraviolet radiation. Over 8100 colonies surviving from 7.4 x 10 6 cells exposed to radiation were screened on citrate agar for detection and isolation of mutants with increased flavor and/or acid production. Of the survivors, 960 were type-I mutants that exhibited clear zone on citrate agar after 18 h (presumed to be high diacetyl producers), and 288 were type-II mutants which did not exhibit clear zones on citrate agar for up to 72 h (high acid producers). Type-II mutants produced an average .93 percent titratable acidity which was 34 percent more than the .69 percent of the parent. Reduction in titratable acidity (56 percent less) was considerable in type-I mutants, compared with the parent culture. Diacetyl + acetoin production by type-I mutants was 137.9 ppM which has 4.5 times more than that of the parental strain. Acetaldehyde production in the mutants varied from 1.5 to 34.5 ppM (parent culture 3.0 ppM). The mutants with increased acid and high acetoin plus diacetyl production were stable after 50 subcultures in milk

Characterization of Partially Purified Bacteriocin Like Substance (BLIS Produced by Probiotic Lactobacillus Strains

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Saeed Ismail Khanian

2014-05-01

Full Text Available Background: There is an increasing interest in search for antimicrobial peptides (bacteriocins and bacteriocin-like compounds produced by lactic acid bacteria (LAB because of their potential to be used as antimicrobial agents for improving the safety of food products. Objectives: The main objective of study was to evaluate the antibacterial potential of locally isolated Lactic Acid bacteria (LAB and determine their bacteriocin producing ability in in-vitro conditions. Materials and Methods: The antibacterial activity of 77 isolated LAB strains was tested against a number of pathogens by well-diffusion method. The isolates demonstrating antimicrobial potential were selected and tested for the production of bacteriocin or bacteriocin like substance. The bacteriocin produced by two of the isolates were partially purified and characterized. Results: The results indicated the neutralized supernatant fluid of two of the isolates identified as L. brevis LB32 and L. pentosus LP05, were active against the growth of Listeria monocytogenes, Salmonella enteritidis, Shigella dysenteriae, Staphylococcus aureus and Streptococcus pneumoniae. Additionally, L. brevis LB32 was able to inhibit the growth of Salmonella typhi and Klebsiella pneumoniae, while, S. pnuemoniae and L. monocytogenes appeared to be the most sensitive strain as apparent by highest zone of inhibition against these pathogens, respectively. The antimicrobial activity in the supernatant fluids of the mentioned strains remained unaffected after treating with enzymes catalase, lipase and lysozyme, while were strongly sensitive to the action of proteolytic enzymes, suggesting the presence of bacteriocin like inhibitory substance (BLIS in the two isolates. The inhibitory substance produced by the two isolates appeared heat resistant and tolerated 100˚C and 121˚C for 55 minutes and 20 minutes, respectively. Partial purification of the concentrated culture supernatant fluids of L. brevis LB32 and L

Comparative genomics of citric-acid producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88

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Grigoriev, Igor V.; Baker, Scott E.; Andersen, Mikael R.; Salazar, Margarita P.; Schaap, Peter J.; Vondervoot, Peter J.I. van de; Culley, David; Thykaer, Jette; Frisvad, Jens C.; Nielsen, Kristen F.; Albang, Richard; Albermann, Kaj; Berka, Randy M.; Braus, Gerhard H.; Braus-Stromeyer, Susanna A.; Corrochano, Luis M.; Dai, Ziyu; Dijck, Piet W.M. van; Hofmann, Gerald; Lasure, Linda L.; Magnusson, Jon K.; Meijer, Susan L.; Nielsen, Jakob B.; Nielsen, Michael L.; Ooyen, Albert J.J. van; Panther, Kathyrn S.; Pel, Herman J.; Poulsen, Lars; Samson, Rob A.; Stam, Hen; Tsang, Adrian; Brink, Johannes M. van den; Atkins, Alex; Aerts, Andrea; Shapiro, Harris; Pangilinan, Jasmyn; Salamov, Asaf; Lou, Yigong; Lindquist, Erika; Lucas, Susan; Grimwood, Jane; Kubicek, Christian P.; Martinez, Diego; Peij, Noel N.M.E. van; Roubos, Johannes A.; Nielsen, Jens

2011-04-28

The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compels additional exploration. We therefore undertook whole genome sequencing of the acidogenic A. niger wild type strain (ATCC 1015), and produced a genome sequence of very high quality. Only 15 gaps are present in the sequence and half the telomeric regions have been elucidated. Moreover, sequence information from ATCC 1015 was utilized to improve the genome sequence of CBS 513.88. Chromosome-level comparisons uncovered several genome rearrangements, deletions, a clear case of strain-specific horizontal gene transfer, and identification of 0.8 megabase of novel sequence. Single nucleotide polymorphisms per kilobase (SNPs/kb) between the two strains were found to be exceptionally high (average: 7.8, maximum: 160 SNPs/kb). High variation within the species was confirmed with exo-metabolite profiling and phylogenetics. Detailed lists of alleles were generated, and genotypic differences were observed to accumulate in metabolic pathways essential to acid production and protein synthesis. A transcriptome analysis revealed up-regulation of the electron transport chain, specifically the alternative oxidative pathway in ATCC 1015, while CBS 513.88 showed significant up-regulation of genes relevant to glucoamylase A production, such as tRNA-synthases and protein transporters. Our results and datasets from this integrative systems biology analysis resulted in a snapshot of fungal evolution and will support further optimization of cell factories based on filamentous fungi.[Supplemental materials (10 figures, three text documents and 16 tables) have been made available

The hydrolytic enzymes produced by fungi strains isolated from the sand and soil of recreational areas

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Kurnatowski, Piotr; Wójcik, Anna; Błaszkowska, Joanna; Góralska, Katarzyna

2016-10-01

The pathogenicity of fungi depends on, inter alia, the secretion of hydrolytic enzymes. The aim of this study was to determine the enzymatic activity of yeasts and yeast-like fungi isolated from children’s recreation areas, and compare the results with literature data of strains obtained from patients with mycoses. The enzymatic activity of 96 strains was assessed using an API ZYM kit (bioMerieux, France) and their biotypes were established. The fungal species were found to produce from 16 to 19 hydrolases: the most active were: leucine arylamidase (e5), acid phosphatase (e10), alkaline phosphatase (e1), naphthol-AS-BI-phosphohydrolase (e11), esterase – C4 (e2), β-galac - tosidase (e13) and β-glucosidase (e16). In addition, 13 biotypes characteristic of particular species of fungi were defined. Most strains could be categorized as biotypes C2 – 39.5% and A – 26%. The examined fungal strains isolated from recreational areas have selected biochemical characteristics i.e. production of hydrolases, which demonstrate their pathogenicity. They produce a number of enzymes which are also present in strains isolated from patients with mycoses, including: leucine arylamidase (e5), acid phosphatase (e10), naphthol-AS-BI-phosphohydrolase (e11) and alkaline phosphatase (e1). The biotypes identified in the course of this study (A, B3, B4, C1, C6 and D3) have been also reported in cases of fungal infection. Therefore, the fungi present in the sand and soil of recreational have pathogenic properties and are possible factors of fungal infection among children.

Deoxyribonucleic acid-deficient strains of Candida albicans.

OpenAIRE

Olaiya, A F; Steed, J R; Sogin, S J

1980-01-01

We analyzed a series of germ tube-negative variants isolated from Candida albicans 3153A for deoxyribonucleic acid content. As analyzed by flow microfluorometry, the deoxyribonucleic acid level in these variant strains was 50% of that of the parental strain and equivalent to that of haploid Saccharomyces cerevisiae. This finding was confirmed by comparison of survival rates when exposed to the mutagens ultraviolet light, ethyl methane sulfonate, and methyl methane sulfonate. The diameter of t...

Draft Genome Sequence of Lactobacillus delbrueckii subsp. bulgaricus CRL871, a Folate-Producing Strain Isolated from a Northwestern Argentinian Yogurt.

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Laiño, Jonathan Emiliano; Hebert, Elvira María; Savoy de Giori, Graciela; LeBlanc, Jean Guy

2015-06-25

Lactobacillus delbrueckii subsp. bulgaricus CRL871 is the first strain of L. delbrueckii subsp. bulgaricus reported as a folate-producing strain. We report the draft genome sequence of L. delbrueckii subsp. bulgaricus CRL871 (2,063,981 bp, G+C content of 49.1%). This strain is of great biotechnological importance to the dairy industry because it constitutes an alternative to folic acid fortification. Copyright © 2015 Laiño et al.

Characterization of extracellular vitamin B12 producing Lactobacillus plantarum strains and assessment of the probiotic potentials.

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Li, Ping; Gu, Qing; Yang, Lanlan; Yu, Yue; Wang, Yuejiao

2017-11-01

We investigated extracellular vitamin B 12 -producing Lactobacillus strains and their characteristics in tolerance to environmental stresses, gastric acid and bile salts. Two isolates, Lactobacillus plantarum LZ95 and CY2, showed high extracellular B 12 production, 98±15μg/L and 60±9μg/L respectively. Extracellular B 12 from LZ95 were identified as adenosylcobalamin and methylcobalamin using a combination of solid phase extraction and reverse-phase HPLC, while that from CY2 was adenosylcobalamin. Both strains grew under environmental stresses, and LZ95 exhibited better tolerance to low temperature and high ethanol concentration. LZ95 also showed good viability when exposed to gastric acid (pH 2.0 and 3.0) and bile salts (0.3%) as well as good adhesion to Caco-2 cells. The viability of CY2 was significantly reduced under low pH and exposure to bile salt. Together, extracellular B 12 producer LZ95 with good probiotic properties might be a candidate for in situ B 12 fortification in the food industry. Copyright © 2017 Elsevier Ltd. All rights reserved.

Functionality of exopolysaccharides produced by lactic acid bacteria in an in vitro gastric system.

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Mozzi, F; Gerbino, E; Font de Valdez, G; Torino, M I

2009-07-01

To evaluate whether slime-exopolysaccharides (EPS) or capsular-polysaccharide (CPS) production could protect the polymer-producing strains Streptococcus thermophilus CRL 1190 and Lactobacillus casei CRL 87 against the harsh conditions of an in vitro gastric system (GS). EPS stability on the GS was studied. An in vitro GS model containing human saliva and gastric juice was standardized. Polymer functionality on the cell viability and metabolic activity of the EPS-producing strains in the GS acidic conditions was evaluated. Two isogenic EPS/CPS deficient mutants were used for comparison. EPS or CPS conferred no significant protection on the cell viability of the studied strains after passage through the GS conditions. However, the phospho- and beta-galactosidase activities of the EPS(+) strains were higher than those of the EPS(-). Cytoplasmic alterations in the wild-type and mutant strains and partial degradation of both EPS were detected. The presence of EPS/CPS protected the metabolic activity of the assayed LAB strains, but had no effect on survival at low pH. The presence of EPS/CPS as well as polymer resistance to the harsh conditions of the human GS could impact positively in probiotic strains to exert their properties in the host.

Kinetic analysis of strains of lactic acid bacteria and acetic acid bacteria in cocoa pulp simulation media toward development of a starter culture for cocoa bean fermentation.

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Lefeber, Timothy; Janssens, Maarten; Camu, Nicholas; De Vuyst, Luc

2010-12-01

The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes.

Proteome response of Tribolium castaneum larvae to Bacillus thuringiensis toxin producing strains.

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Estefanía Contreras

Full Text Available Susceptibility of Tribolium castaneum (Tc larvae was determined against spore-crystal mixtures of five coleopteran specific and one lepidopteran specific Bacillus thuringiensis Cry toxin producing strains and those containing the structurally unrelated Cry3Ba and Cry23Aa/Cry37Aa proteins were found toxic (LC(50 values 13.53 and 6.30 µg spore-crystal mixture/µL flour disc, respectively. Using iTRAQ combined with LC-MS/MS allowed the discovery of seven novel differentially expressed proteins in early response of Tc larvae to the two active spore-crystal mixtures. Proteins showing a statistically significant change in treated larvae compared to non-intoxicated larvae fell into two major categories; up-regulated proteins were involved in host defense (odorant binding protein C12, apolipophorin-III and chemosensory protein 18 and down-regulated proteins were linked to metabolic pathways affecting larval metabolism and development (pyruvate dehydrogenase Eα subunit, cuticular protein, ribosomal protein L13a and apolipoprotein LI-II. Among increased proteins, Odorant binding protein C12 showed the highest change, 4-fold increase in both toxin treatments. The protein displayed amino acid sequence and structural homology to Tenebrio molitor 12 kDa hemolymph protein b precursor, a non-olfactory odorant binding protein. Analysis of mRNA expression and mortality assays in Odorant binding protein C12 silenced larvae were consistent with a general immune defense function of non-olfactory odorant binding proteins. Regarding down-regulated proteins, at the transcriptional level, pyruvate dehydrogenase and cuticular genes were decreased in Tc larvae exposed to the Cry3Ba producing strain compared to the Cry23Aa/Cry37Aa producing strain, which may contribute to the developmental arrest that we observed with larvae fed the Cry3Ba producing strain. Results demonstrated a distinct host transcriptional regulation depending upon the Cry toxin treatment. Knowledge

Diversity of Lactobacillus reuteri Strains in Converting Glycerol into 3-Hydroxypropionic Acid.

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Burgé, G; Saulou-Bérion, C; Moussa, M; Pollet, B; Flourat, A; Allais, F; Athès, V; Spinnler, H E

2015-10-01

The present study aims at comparing the performances of three Lactobacillus reuteri strains (DSM 20016, DSM 17938, and ATCC 53608) in producing 3-hydroxypropionic acid (3-HP) from glycerol and at exploring inhibition phenomena during this bioconversion. Differences were highlighted between the three strains in terms of 3-HP production yield, kinetics of substrate consumption, and metabolite production. With a maximal productivity in non-optimal conditions (free pH) around 2 g.L(-1).h(-1) of 3-HP and 4 g.L(-1).h(-1) of 3-hydroxypropionaldehyde (3-HPA) depending on the strain, this study confirmed the potential of L. reuteri for the biotechnological production of 3-HP. Moreover, the molar ratios of 3-HP to 1,3-propanediol (1,3-PDO) obtained for the three strains (comprised between 1.25 and 1.65) showed systematically a higher 3-HP production. From these results, the DSM 17938 strain appeared to be the most promising strain. The impact of glycerol bioconversion on the bacteria's physiological state (a decrease of around 40 % in DSM 17938 cells showing an enzymatic activity after 3 h) and survival (total loss of cultivability after 2 or 3 h depending on the strains) was revealed and discussed. The effect of each metabolite on L. reuteri DSM 17938 was further investigated, displaying a drastic inhibition caused by 3-HPA, while 3-HP induced lower impact and only at acidic pH.

Lactic Acid Production from Pretreated Hydrolysates of Corn Stover by a Newly Developed Bacillus coagulans Strain

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Jiang, Ting; Qiao, Hui; Zheng, Zhaojuan; Chu, Qiulu; Li, Xin; Yong, Qiang; Ouyang, Jia

2016-01-01

An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP) mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH) of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH), condensed acid-catalyzed liquid hot water hydrolysate (CALH) and condensed acid-catalyzed sulfite hydrolysate (CASH) as substrates, the concentration of lactic acid reached 45.39, 16.83, and 18.71 g/L by B. coagulans GKN316, respectively. But for B. coagulans NL01, only CASEH could be directly fermented to produce 15.47 g/L lactic acid. The individual inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF), vanillin, syringaldehyde and p-hydroxybenzaldehyde (pHBal) on xylose utilization by B. coagulans GKN316 was also studied. The strain B. coagulans GKN316 could effectively convert these toxic inhibitors to the less toxic corresponding alcohols in situ. These results suggested that B. coagulans GKN316 was well suited to production of lactic acid from undetoxified lignocellulosic hydrolysates. PMID:26863012

Lactic Acid Production from Pretreated Hydrolysates of Corn Stover by a Newly Developed Bacillus coagulans Strain.

Science.gov (United States)

Jiang, Ting; Qiao, Hui; Zheng, Zhaojuan; Chu, Qiulu; Li, Xin; Yong, Qiang; Ouyang, Jia

2016-01-01

An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP) mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH) of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH), condensed acid-catalyzed liquid hot water hydrolysate (CALH) and condensed acid-catalyzed sulfite hydrolysate (CASH) as substrates, the concentration of lactic acid reached 45.39, 16.83, and 18.71 g/L by B. coagulans GKN316, respectively. But for B. coagulans NL01, only CASEH could be directly fermented to produce 15.47 g/L lactic acid. The individual inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF), vanillin, syringaldehyde and p-hydroxybenzaldehyde (pHBal) on xylose utilization by B. coagulans GKN316 was also studied. The strain B. coagulans GKN316 could effectively convert these toxic inhibitors to the less toxic corresponding alcohols in situ. These results suggested that B. coagulans GKN316 was well suited to production of lactic acid from undetoxified lignocellulosic hydrolysates.

Lactic Acid Production from Pretreated Hydrolysates of Corn Stover by a Newly Developed Bacillus coagulans Strain.

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Ting Jiang

Full Text Available An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH, condensed acid-catalyzed liquid hot water hydrolysate (CALH and condensed acid-catalyzed sulfite hydrolysate (CASH as substrates, the concentration of lactic acid reached 45.39, 16.83, and 18.71 g/L by B. coagulans GKN316, respectively. But for B. coagulans NL01, only CASEH could be directly fermented to produce 15.47 g/L lactic acid. The individual inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF, vanillin, syringaldehyde and p-hydroxybenzaldehyde (pHBal on xylose utilization by B. coagulans GKN316 was also studied. The strain B. coagulans GKN316 could effectively convert these toxic inhibitors to the less toxic corresponding alcohols in situ. These results suggested that B. coagulans GKN316 was well suited to production of lactic acid from undetoxified lignocellulosic hydrolysates.

LYOPHILIZATION EFFECT ON PRODUCTIVITY OF BUTANOL-PRODUCING STRAINS

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O. O. Tigunova

2016-10-01

Full Text Available Investigation of lyophilization effect on the productivity of butanol-producing strains was the aim of our research. For this purpose we used butanol-producing strains; technical glycerol; biomass of switchgrass Panicum virgatum L. Lyophilization was performed using a lyophilization-drying. The effect of the protective medium on residual moisture of freezedrying cultures suspensions depending on the concentration of glucose and sucrose was studed. It was shown that the lowest residual moisture was attained by using glucose and sucrose in amount of 10% and if the samples of freeze-drying bacteria had been saved for one month at 4 οC the productivity did not decrease. As temperature preservation was increased the productivity of the cultures was gradually decreased and it was greatly reduced at 30 οC. So the protective medium composition was optimized for lyophilization of butanol-producing strains as follows: sucrose 10.0%; gelatin 10.0%; agar 0.02%. It was shown that the preservation of samples of freeze-drying bacteria for six months at a temperature of 4 οC did not affect the productivity of strains. It was found that cultures could use glycerol as a carbon source for butanol accumulation before lyophilization.

Individual and co-operative roles of lactic acid and hydrogen peroxide in the killing activity of enteric strain Lactobacillus johnsonii NCC933 and vaginal strain Lactobacillus gasseri KS120.1 against enteric, uropathogenic and vaginosis-associated pathogens.

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Atassi, Fabrice; Servin, Alain L

2010-03-01

The mechanism underlying the killing activity of Lactobacillus strains against bacterial pathogens appears to be multifactorial. Here, we investigate the respective contributions of hydrogen peroxide and lactic acid in killing bacterial pathogens associated with the human vagina, urinary tract or intestine by two hydrogen peroxide-producing strains. In co-culture, the human intestinal strain Lactobacillus johnsonii NCC933 and human vaginal strain Lactobacillus gasseri KS120.1 strains killed enteric Salmonella enterica serovar Typhimurium SL1344, vaginal Gardnerella vaginalis DSM 4944 and urinary tract Escherichia coli CFT073 pathogens. The cell-free culture supernatants (CFCSs) produced the same reduction in SL1344, DSM 4944 and CFT073 viability, whereas isolated bacteria had no effect. The killing activity of CFCSs was heat-stable. In the presence of Dulbecco's modified Eagle's minimum essential medium inhibiting the lactic acid-dependent killing activity, CFCSs were less effective at killing of the pathogens. Catalase-treated CFCSs displayed a strong decreased activity. Tested alone, hydrogen peroxide triggered a concentration-dependent killing activity against all three pathogens. Lactic acid alone developed a killing activity only at concentrations higher than that present in CFCSs. In the presence of lactic acid at a concentration present in Lactobacillus CFCSs, hydrogen peroxide displayed enhanced killing activity. Collectively, these results demonstrate that for hydrogen peroxide-producing Lactobacillus strains, the main metabolites of Lactobacillus, lactic acid and hydrogen peroxide, act co-operatively to kill enteric, vaginosis-associated and uropathogenic pathogens.

Isolation and characterization of a biosurfactant producing strain, Brevibacilis brevis HOB1.

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Haddad, Namir I A; Wang, Ji; Mu, Bozhong

2008-12-01

Biosurfactant-producing bacteria were isolated from the production water of an oil field. Isolates were screened for biosurfactant production using surface tension test. The highest reduction of surface tension was achieved with a bacterial strain which was identified by 16S rRNA gene sequencing as Brevibacilis brevis HOB1. It has been investigated using different carbon and nitrogen sources. It showed that the strain was able to grow and reduce the surface tension of the broth to 29 mN/m on commercial sugar and maltose, and to 32 mN/m on glucose after 72 h of growth. The maximum amount of biosurfactant was obtained when nitrate ions were supplied as nitrogen source. Biosurfactant produced by Brevibacilis brevis HOB1 was confirmed as a lipopeptide class of biosurfactant using TLC test and mass spectra. Lipopeptide isoforms were isolated from cell-free supernatants by acid-precipitation followed by one step of chromatographic separation on solid-phase ODS C18 column. The separation was confirmed by HPLC and ESI Q-TOF MS spectroscopy. Comparing the mass data obtained and the mass numbers reported for the lipopeptide complexes from other strains, it can be concluded that the major lipopeptide product of Brevibacilis brevis HOB1 is the surfactin isoform. This lipopeptide showed strong antibacterial and antifungal activity. It is a candidate for the biocontrol of pathogens in agriculture and other industries.

Water Kefir grain as a source of potent dextran producing lactic acid bacteria

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Davidović Slađana Z.

2015-01-01

Full Text Available Water kefir is abeverage fermented by a microbial consortium captured in kefir grains. The kefir grains matrix is composed of polysaccharide, primarily dextran, whichis produced by members of the microbial consortium. In this study, we have isolated lactic acid bacteria (LAB from non-commercial water kefir grains (from Belgrade, Serbia and screened for dextran production. Among twelve Lisolates threeproduced slime colonies on modified MRS (mMRS agar containing sucrose instead of glucoseand were presumed to produce dextran. Three LABwere identified based on morphological, physiological and biochemical characteristics and 16S rRNA sequencing as Leuconostoc mesenteroides(strains T1 and T3 and Lactobacillus hilgardii (strain T5. The isolated strains were able to synthesize a substantial amount of dextran in mMRS broth containing 5% sucrose. Maximal yields (11.56, 18.00 and 18.46 g/l were obtained after 16h, 20h and 32h for T1, T3 and T5, respectively. Optimal temperature for dextran production was 23oC for two Leuconostoc mesenteroides strains and 30oC for Lactobacillus hilgardii strain. The produced dextrans were identified based on paper chromatography while the main structure characteristics of purified dextranwere observed by FT-IR spectroscopy. Our study shows that water kefir grains are a natural source of potent dextranproducing LAB. [Projekat Ministarstva nauke Republike Srbije, br. TR 31035

The Effect of Phenazine-1-Carboxylic Acid on Mycelial Growth of Botrytis cinerea Produced by Pseudomonas aeruginosa LV Strain

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Ane S. Simionato

2017-06-01

Full Text Available One of the most important postharvest plant pathogens that affect strawberries, grapes and tomatoes is Botrytis cinerea, known as gray mold. The fungus remains in latent form until spore germination conditions are good, making infection control difficult, causing great losses in the whole production chain. This study aimed to purify and identify phenazine-1-carboxylic acid (PCA produced by the Pseudomonas aeruginosa LV strain and to determine its antifungal activity against B. cinerea. The compounds produced were extracted with dichloromethane and passed through a chromatographic process. The purity level of PCA was determined by reversed-phase high-performance liquid chromatography semi-preparative. The structure of PCA was confirmed by nuclear magnetic resonance and electrospray ionization mass spectrometry. Antifungal activity was determined by the dry paper disk and minimum inhibitory concentration (MIC methods and identified by scanning electron microscopy and confocal microscopy. The results showed that PCA inhibited mycelial growth, where MIC was 25 μg mL-1. Microscopic analysis revealed a reduction in exopolysaccharide (EPS formation, showing distorted and damaged hyphae of B. cinerea. The results suggested that PCA has a high potential in the control of B. cinerea and inhibition of EPS (important virulence factor. This natural compound is a potential alternative to postharvest control of gray mold disease.

Biological characterization of lead-enhanced exopolysaccharide produced by a lead resistant Enterobacter cloacae strain P2B.

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Naik, Milind Mohan; Pandey, Anju; Dubey, Santosh Kumar

2012-09-01

A lead resistant bacterial strain isolated from effluent of lead battery manufacturing company of Goa, India has been identified as Enterobacter cloacae strain P2B based on morphological, biochemical characters, FAME profile and 16S rDNA sequence data. This bacterial strain could resist lead nitrate up to 1.6 mM. Significant increase in exopolysaccharide (EPS) production was observed as the production increased from 28 to 108 mg/L dry weight when exposed to 1.6 mM lead nitrate in Tris buffered minimal medium. Fourier-transformed infrared spectroscopy of this EPS revealed presence of several functional groups involved in metal binding viz. carboxyl, hydroxyl and amide groups along with glucuronic acid. Gas chromatography coupled with mass spectrometry analysis of alditol-acetate derivatives of acid hydrolysed EPS produced in presence of 1.6 mM lead nitrate demonstrated presence of several neutral sugars such as rhamnose, arabinose, xylose, mannose, galactose and glucose, which contribute to lead binding hydroxyl groups. Scanning electron microscope coupled with energy dispersive X-ray spectrometric analysis of this lead resistant strain exposed to 1.6 mM lead nitrate interestingly revealed mucous EPS surrounding bacterial cells which sequestered 17 % lead (as weight %) extracellularly and protected the bacterial cells from toxic effects of lead. This lead resistant strain also showed multidrug resistance. Thus these results significantly contribute to better understanding of structure, function and environmental application of lead-enhanced EPSs produced by bacteria. This lead-enhanced biopolymer can play a very important role in bioremediation of several heavy metals including lead.

Megasphaera hexanoica sp. nov., a medium-chain carboxylic acid-producing bacterium isolated from a cow rumen.

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Jeon, Byoung Seung; Kim, Seil; Sang, Byoung-In

2017-07-01

Strain MHT, a strictly anaerobic, Gram-stain-negative, non-spore-forming, spherical coccus or coccoid-shaped microorganism, was isolated from a cow rumen during a screen for hexanoic acid-producing bacteria. The microorganism grew at 30-40 °C and pH 5.5-7.5 and exhibited production of various short- and medium-chain carboxylic acids (acetic acid, butyric acid, pentanoic acid, isobutyric acid, isovaleric acid, hexanoic acid, heptanoic acid and octanoic acid), as well as H2 and CO2 as biogas. Phylogenetic analysis based on 16S rRNA gene sequencing demonstrated that MHT represents a member of the genus Megasphaera, with the closest relatives being Megapsphaera indica NMBHI-10T (94.1 % 16S rRNA sequence similarity), Megasphaera elsdenii DSM 20460T (93.8 %) and Megasphaera paucivorans DSM 16981T (93.8 %). The major cellular fatty acids produced by MHT included C12 : 0, C16 : 0, C18 : 1cis 9, and C18 : 0, and the DNA G+C content of the MHT genome is 51.8 mol%. Together, the distinctive phenotypic and phylogenetic characteristics of MHT indicate that this microorganism represents a novel species of the genus Megasphaera, for which the name Megasphaera hexanoica sp. nov. is herein proposed. The type strain of this species is MHT (=KCCM 43214T=JCM 31403T).

Structural characterization of bioengineered α-D-glucans produced by mutant glucansucrase GTF180 enzymes of lactobacillus reuteri strain 180

NARCIS (Netherlands)

Leeuwen, S.S. van; Kralj, S.; Eeuwema, W.; Gerwig, G.J.; Dijkhuizen, L.; Kamerling, J.P.

2009-01-01

Mutagenesis of specific amino acid residues of the glucansucrase (GTF180) enzyme from Lactobacillus reuteri strain 180 yielded 12 mutant enzymes that produced modified exopolysaccharides (mEPSs) from sucrose. Ethanol-precipitated and purified mEPSs were subjected to linkage analysis, Smith

Structural Characterization of Bioengineered alpha-D-Glucans Produced by Mutant Glucansucrase GTF180 Enzymes of Lactobacillus reuteri Strain 180

NARCIS (Netherlands)

van Leeuwen, Sander S.; Kralj, Slavko; Eeuwema, Wieger; Gerwig, Gerrit J.; Dijkhuizen, Lubbert; Kamerling, Johannis P.

Mutagenesis of specific amino acid residues of the glucansucrase (GTF180) enzyme from Lactobacillus reuteri strain 180 yielded 12 mutant enzymes that produced modified exopolysaccharides (mEPSs) from sucrose. Ethanol-precipitated and purified mEPSs were subjected to linkage analysis, Smith

Improving itaconic acid production through genetic engineering of an industrial Aspergillus terreus strain.

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Huang, Xuenian; Lu, Xuefeng; Li, Yueming; Li, Xia; Li, Jian-Jun

2014-08-11

Itaconic acid, which has been declared to be one of the most promising and flexible building blocks, is currently used as monomer or co-monomer in the polymer industry, and produced commercially by Aspergillus terreus. However, the production level of itaconic acid hasn't been improved in the past 40 years, and mutagenesis is still the main strategy to improve itaconate productivity. The genetic engineering approach hasn't been applied in industrial A. terreus strains to increase itaconic acid production. In this study, the genes closely related to itaconic acid production, including cadA, mfsA, mttA, ATEG_09969, gpdA, ATEG_01954, acoA, mt-pfkA and citA, were identified and overexpressed in an industrial A. terreus strain respectively. Overexpression of the genes cadA (cis-aconitate decarboxylase) and mfsA (Major Facilitator Superfamily Transporter) enhanced the itaconate production level by 9.4% and 5.1% in shake flasks respectively. Overexpression of other genes showed varied effects on itaconate production. The titers of other organic acids were affected by the introduced genes to different extent. Itaconic acid production could be improved through genetic engineering of the industrially used A. terreus strain. We have identified some important genes such as cadA and mfsA, whose overexpression led to the increased itaconate productivity, and successfully developed a strategy to establish a highly efficient microbial cell factory for itaconate protuction. Our results will provide a guide for further enhancement of the itaconic acid production level through genetic engineering in future.

Technological properties of bacteriocin-producing lactic acid bacteria isolated from Pico cheese an artisanal cow's milk cheese.

Science.gov (United States)

Ribeiro, S C; Coelho, M C; Todorov, S D; Franco, B D G M; Dapkevicius, M L E; Silva, C C G

2014-03-01

Evaluate technologically relevant properties from bacteriocin-producing strains to use as starter/adjunct cultures in cheese making. Eight isolates obtained from Pico cheese produced in Azores (Portugal) were found to produce bacteriocins against Listeria monocytogenes and three isolates against Clostridium perfringens. They were identified as Lactococcus lactis and Enterococcus faecalis and submitted to technological tests: growth at different conditions of temperature and salt, acid production, proteolysis, lipolysis, coexistence, enzymatic profile and autolytic capacity. Safety evaluation was performed by evaluating haemolytic, gelatinase and DNase activity, resistance to antibiotics and the presence of virulence genes. Some isolates presented good technological features such as high autolytic activity, acid and diacetyl production. Lactococcus lactis was negative for all virulence genes tested and inhibit the growth of all Lactic acid bacteria (LAB) isolates. Enterococci were positive for the presence of some virulence genes, but none of the isolates were classified as resistant to important antibiotics. The bacteriocin-producing Lc. lactis present good potential for application in food as adjunct culture in cheese production. The study also reveals good technological features for some Enterococcus isolates. Bacteriocin-producing strains presented important technological properties to be exploited as new adjunct culture for the dairy industry, influencing flavour development and improve safety. © 2013 The Society for Applied Microbiology.

Kinetic Analysis of Strains of Lactic Acid Bacteria and Acetic Acid Bacteria in Cocoa Pulp Simulation Media toward Development of a Starter Culture for Cocoa Bean Fermentation ▿

Science.gov (United States)

Lefeber, Timothy; Janssens, Maarten; Camu, Nicholas; De Vuyst, Luc

2010-01-01

The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes. PMID:20889778

Isolation and characterization of lipase-producing Bacillus strains ...

African Journals Online (AJOL)

Bacillus strains (B1 - B5) producing extra cellular lipase were isolated from the soil sample of coconut oil industry. The strains were identified by morphological and biochemical characters. Growth of the organisms and lipase production were measured with varying pH (4 - 9) temperature (27, 37 and 47ºC) and various ...

Breeding study of hyper citric acid strain by progressive heavy ion irradiation

International Nuclear Information System (INIS)

Chen Jihong; Hu Wei; Li Wenjian; Liu Jing; Wang Shuyang; Wei Zihao

2013-01-01

Heavy "1"2C"6"+ ion beams in various high doses were employed to irradiate H3001 strain for screening Aspergillus niger strain for hyper citric acid production. Three high-yield strains were obtained after shaker fermentation test. Among the three strains, the strain hw317 was implemented shaker fermentation for stability test and 10∼100 L pilot fermentation tank for citric acid productive maximization. Acid-base neutralization method was applied to determinate the content of citric acid in fermented liquid. The results showed that: when the secondary heavy ion "1"2C"6"+ dose was 857.8 Gy, both of the fatality rate (94.5%) and the positive mutation rate (8%) were highest. Through the shaker fermentation tests and 10∼100 L pilot fermentation test, one strain hw317 was screened and obtained for hyper citric acid production. Consequently, the final citric acid acidity can reach up to 19.2±0.2% with controlling fermentation cycle for 60 h. (authors)

Characterization of high exopolysaccharide-producing Lactobacillus strains isolated from mustard pickles for potential probiotic applications.

Science.gov (United States)

Huang, Jing-Yao; Kao, Cheng-Yen; Liu, We-Sin; Fang, Tony J

2017-06-01

The aim of this study was to characterize high exopolysaccharide (EPS)-producing lactic acid bacteria (LAB) isolated from mustard pickles in Taiwan for potential probiotic applications. Among 39 collected LAB strains, four most productive EPS-producing strains were selected for further analysis. Comparative analyses of 16S rDNA genes rpoA and pheS sequences demonstrated that these strains were members of Lactobacillus plantarum-group (LPG). NCD 2, NLD 4, SLC 13, and NLD 16 showed survival rates of 95.83% ± 0.49%, 95.07% ± 0.64%, 105.84% ± 0.82%, and 99.65% ± 0.31% under simulated gastrointestinal conditions, respectively. No cytotoxic effects on macrophage RAW 264.7 cells were observed when they were treated with a low dose (1 μg/ml) of stimulants extracted from the tested LAB strains. The production of nitric oxide in RAW 264.7 cells incubated with various LAB stimulants showed a dose-dependent increase. Among the four strains, SLC 13 showed higher inhibitory activity on growth of Enterococcus faecalis (BCRC 12302) and Yersinia enterocolitica (BCRC 10807). NLD 4 showed strong inhibitory activity against Escherichia coli O157:H7 (ATCC 43894) as compared with the other three strains. In summary, our results suggest that Lactobacillus pentosus SLC 13 may be a good candidate for probiotic applications and for development of antibacterial compounds. [Int Microbiol 20(2):75-84 (2017)]. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

Citric acid production from extract of Jerusalem artichoke tubers by the genetically engineered yeast Yarrowia lipolytica strain 30 and purification of citric acid.

Science.gov (United States)

Wang, Ling-Fei; Wang, Zhi-Peng; Liu, Xiao-Yan; Chi, Zhen-Ming

2013-11-01

In this study, citric acid production from extract of Jerusalem artichoke tubers by the genetically engineered yeast Yarrowia lipolytica strain 30 was investigated. After the compositions of the extract of Jerusalem artichoke tubers for citric acid production were optimized, the results showed that natural components of extract of Jerusalem artichoke tubers without addition of any other components were suitable for citric acid production by the yeast strain. During 10 L fermentation using the extract containing 84.3 g L(-1) total sugars, 68.3 g L(-1) citric acid was produced and the yield of citric acid was 0.91 g g(-1) within 336 h. At the end of the fermentation, 9.2 g L(-1) of residual total sugar and 2.1 g L(-1) of reducing sugar were left in the fermented medium. At the same time, citric acid in the supernatant of the culture was purified. It was found that 67.2 % of the citric acid in the supernatant of the culture was recovered and purity of citric acid in the crystal was 96 %.

Use of superoxide dismutase and catalase producing lactic acid bacteria in TNBS induced Crohn's disease in mice.

Science.gov (United States)

LeBlanc, Jean Guy; del Carmen, Silvina; Miyoshi, Anderson; Azevedo, Vasco; Sesma, Fernando; Langella, Philippe; Bermúdez-Humarán, Luis G; Watterlot, Laurie; Perdigon, Gabriela; de Moreno de LeBlanc, Alejandra

2011-02-10

Reactive oxygen species are involved in various aspects of intestinal inflammation and tumor development. Decreasing their levels using antioxidant enzymes, such as catalase (CAT) or superoxide dismutase (SOD) could therefore be useful in the prevention of certain diseases. Lactic acid bacteria (LAB) are ideal candidates to deliver these enzymes in the gut. In this study, the anti-inflammatory effects of CAT or SOD producing LAB were evaluated using a trinitrobenzenesulfonic acid (TNBS) induced Crohn's disease murine model. Engineered Lactobacillus casei BL23 strains producing either CAT or SOD, or the native strain were given to mice before and after intrarectal administration of TNBS. Animal survival, live weight, intestinal morphology and histology, enzymatic activities, microbial translocation to the liver and cytokines released in the intestinal fluid were evaluated. The mice that received CAT or SOD-producing LAB showed a faster recovery of initial weight loss, increased enzymatic activities in the gut and lesser extent of intestinal inflammation compared to animals that received the wild-type strain or those that did not receive bacterial supplementation. Our findings suggest that genetically engineered LAB that produce antioxidant enzymes could be used to prevent or decrease the severity of certain intestinal pathologies. Copyright © 2010 Elsevier B.V. All rights reserved.

Fatty acid-producing hosts

Science.gov (United States)

Pfleger, Brian F; Lennen, Rebecca M

2013-12-31

Described are hosts for overproducing a fatty acid product such as a fatty acid. The hosts include an exogenous nucleic acid encoding a thioesterase and, optionally, an exogenous nucleic acid encoding an acetyl-CoA carboxylase, wherein an acyl-CoA synthetase in the hosts are functionally delected. The hosts prefereably include the nucleic acid encoding the thioesterase at an intermediate copy number. The hosts are preferably recominantly stable and growth-competent at 37.degree. C. Methods of producing a fatty acid product comprising culturing such hosts at 37.degree. C. are also described.

Structure of an extracellular polysaccharide produced by Lactobacillus rhamnosus strain C83

Energy Technology Data Exchange (ETDEWEB)

Vanhaverbeke, C.; Bosso, C.; Colin-Morel, P.; Gey, C.; Heyraud, A. [Centre de Recherches sur les Macromolecules Vegetales, CNRS and Universite Joseph Fourier, B.P.53, F-38041 Grenoble (France); Gamar-Nourani, L.; Blondeau, K.; Simonet, J.-M. [Institut de Genetique et Microbiologie, Laboratoire de Genetique Moleculaire des Bacteries d' Interet Industriel, CNRS URA 2225, Batiment 360, Universite de Paris Sud, F-91405 Orsay (France)

1998-12-31

The extracellular polysaccharide produced by Lactobacillus rhamnosus strain C83 was found to be composed of d-glucose and d-galactose in a molar ratio of 2:3. The primary structure of the polysaccharide was shown by sugar analysis, methylation analysis, FABMS, partial acid hydrolysis and nuclear magnetic resonance (NMR) spectroscopy to consist of a pentasaccharide repeating unit having the following structure:-3)-{alpha}-d-Glcp-(1-2)-{beta}-d-Galf-(1-6)-{alpha}-d-Galp-(1-6) -{alpha}-d-Glcp-(1-3)-{beta}-d-Galf-(1-. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

Structure of an extracellular polysaccharide produced by Lactobacillus rhamnosus strain C83

International Nuclear Information System (INIS)

Vanhaverbeke, C.; Bosso, C.; Colin-Morel, P.; Gey, C.; Heyraud, A.; Gamar-Nourani, L.; Blondeau, K.; Simonet, J.-M.

1998-01-01

The extracellular polysaccharide produced by Lactobacillus rhamnosus strain C83 was found to be composed of d-glucose and d-galactose in a molar ratio of 2:3. The primary structure of the polysaccharide was shown by sugar analysis, methylation analysis, FABMS, partial acid hydrolysis and nuclear magnetic resonance (NMR) spectroscopy to consist of a pentasaccharide repeating unit having the following structure:-3)-α-d-Glcp-(1-2)-β-d-Galf-(1-6)-α-d-Galp-(1-6) -α-d-Glcp-(1-3)-β-d-Galf-(1-. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

Isolation and characterization of exopolysaccharide produced by Vibrio harveyi strain VB23.

Science.gov (United States)

Bramhachari, P V; Dubey, S K

2006-11-01

The aim of the study was to isolate and characterize exopolysaccharide (EPS) produced by Vibrio harveyi strain VB23. Growth and EPS production by V. harveyi strain VB23, was studied in mineral salts medium supplemented with NaCl (1.5%) and glucose (0.2%). The rate of EPS production in batch cultures was highest during the late log phase of growth when compared with stationary growth phase. The exopolymer was recovered from the culture supernatant by using a cold ethanol precipitation-dialysis procedure. Chemical analyses of EPS revealed that it is primarily composed of neutral sugars, uronic acids, proteins and sulfates. The purified EPS revealed prominent functional reactive groups, such as hydroxyl, carboxylic and amides, which correspond to a typical heteropolymeric polysaccharide and the EPS, also possessed good emulsification activity. The gas chromatographic analysis of an alditol acetate-derivatized sample of EPS revealed that it is composed primarily of galactose and glucose. Minor components found were rhamnose, fucose, ribose, arabinose, xylose and mannose. The EPS produced by V. harveyi strain VB23 is a heteropolysaccharide possessing good emulsification activity. EPS was readily isolated from culture supernatants, which suggests that the EPS was a slime-like EPS. This is the first report of EPS characterization in luminous V. harveyi bacteria, which describes the isolation and characterization of an EPS expressed by V. harveyi. The results of the study contributes significantly towards an understanding of the chemical composition and applications of the EPS in environmental biotechnology and bioremediation.

Strain improvement in Streptomyces galilaeus, a producer of anthracycline antibiotics galirubins

International Nuclear Information System (INIS)

Kralovcova, E.; Blumauerova, M.; Vanek, Z.

1977-01-01

The production of epsilon-pyrromycinone glycosides in Streptomyces galilaeus increased 12-fold, with respect to the wild strain, as a result of a sequential procedure including both natural selection and treatment with mutagens (nitrous acid, UV light and γ irradiation). Nitrous acid exhibited the highest mutagenic effect, both in increasing the productivity and in inducing blocked mutants. A mutant strain blocked in the biosynthesis of glycosides and accumulating free epsilon-pyrromycinone as the principal metabolite was obtained. (author)

Purification, biochemical characterization, and genetic cloning of the phytase produced by Burkholderia sp. strain a13.

Science.gov (United States)

Graminho, Eduardo Rezende; Takaya, Naoki; Nakamura, Akira; Hoshino, Takayuki

2015-01-01

A phytase-producing bacterium, Burkholderia sp. a13 (JCM 30421), was isolated from Lake Kasumigaura by enrichment cultivation using minimum medium containing phytic acid as the sole phosphorus source. The phytase production by strain a13 was induced by the presence of phytic acid and repressed by the addition of glucose. The purified enzyme had a molecular weight of 44 kDa and a phytase activity of 174 μmol min(-1) mg(-1). The enzyme showed broad substrate specificity, but the highest activity was observed with phytic acid. The enzyme activity was strongly inhibited by Cu(2+), Zn(2+), Hg(2+), and iodoacetic acid, indicating the requirement of a thiol group for the activity. Genetic cloning reveals that the mature portion of this enzyme consists of 428 amino acids with a calculated molecular weight of 46 kDa. The amino acid sequence showed the highest similarity to the phytase produced by Hafnia alvei with 48% identity; it also contained histidine acid phosphatase (HAP) motifs (RHGXRXP and HD), indicating the classification of this enzyme in the HAP phytase family. We have successfully expressed the cloned gene in Escherichia coli from its putative initiation codon, showing that the gene actually encodes the phytase.

Isolation and characterisation of an enterocin P-producing Enterococcus lactis strain from a fresh shrimp (Penaeus vannamei).

Science.gov (United States)

Ben Braïek, Olfa; Ghomrassi, Hamdi; Cremonesi, Paola; Morandi, Stefano; Fleury, Yannick; Le Chevalier, Patrick; Hani, Khaled; Bel Hadj, Omrane; Ghrairi, Taoufik

2017-06-01

Screening for lactic acid bacteria (LAB) from fresh shrimp samples (Penaeus vannamei) collected from retail seafood markets in the Tunisian's coast, resulted in the isolation of an Enterococcus strain termed Q1. This strain was selected for its antagonistic activity against pathogenic bacteria such as Listeria monocytogenes, Pseudomonas aeruginosa, Lactococcus garvieae and against fungi (Aspergillus niger and Fusarium equiseti). The Q1 strain was characterised using standard morphological and biochemical tests, growth assays at different temperatures, pH and salinity. 16S rRNA, rpoA and pheS gene sequencing, as well as the 16S-23S rRNA intergenic spacer analyses, were combined to identify strain Q1 as a strain of Enterococcus lactis. The bacteriocin produced by E. lactis Q1 is thermostable, active in the pH range from 4.0 to 9.0 and has a bactericidal mode of action. The enterocin P structural gene was detected by specific PCR in strain E. lactis Q1, which is in good agreement with SDS-PAGE data of the purified bacteriocin. A lack of significant antibiotic resistance genes and virulence determinants was confirmed by specific PCRs. This work provides the first description of an enterocin P producer E. lactis strain isolated from a fresh shrimp. Based on its safety properties (absence of haemolytic activity, virulence factors and antibiotic resistance genes), this strain has the potential to be used as a natural additive or adjunct protective culture in food biopreservation and/or probiotic culture.

Divergence in wine characteristics produced by wild and domesticated strains of Saccharomyces cerevisiae

Science.gov (United States)

Hyma, Katie E; Saerens, Sofie M; Verstrepen, Kevin J; Fay, Justin C

2011-01-01

The budding yeast Saccharomyces cerevisiae is the primary species used by wine makers to convert sugar into alcohol during wine fermentation. Saccharomyces cerevisiae is found in vineyards, but is also found in association with oak trees and other natural sources. Although wild strains of S. cerevisiae as well as other Saccharomyces species are also capable of wine fermentation, a genetically distinct group of S. cerevisiae strains is primarily used to produce wine, consistent with the idea that wine making strains have been domesticated for wine production. In this study, we demonstrate that humans can distinguish between wines produced using wine strains and wild strains of S. cerevisiae as well as its sibling species, Saccharomyces paradoxus. Wine strains produced wine with fruity and floral characteristics, whereas wild strains produced wine with earthy and sulfurous characteristics. The differences that we observe between wine and wild strains provides further evidence that wine strains have evolved phenotypes that are distinct from their wild ancestors and relevant to their use in wine production. PMID:22093681

Volatile compounds of Aspergillus strains with different abilities to produce ochratoxin A.

Science.gov (United States)

Jeleń, Henryk H; Grabarkiewicz-Szczesna, Jadwiga

2005-03-09

Volatile compounds emitted by Aspergillus strains having different abilities to produce ochratoxin A were investigated. Thirteen strains of Aspergillus ochraceus, three belonging to the A. ochraceus group, and eight other species of Aspergillus were examined for their abilities to produce volatile compounds and ochratoxin A on a wheat grain medium. The profiles of volatile compounds, analyzed using SPME, in all A. ochraceus strains, regardless of their toxeginicity, were similar and comprised mainly of 1-octen-3-ol, 3-octanone, 3-octanol, 3-methyl-1-butanol, 1-octene, and limonene. The prevailing compound was always 1-octen-3-ol. Mellein, which forms part of the ochratoxin A molecule, was found in both toxigenic and nontoxigenic strains. Volatile compounds produced by other Aspergillus strains were similar to those of A. ochraceus. Incubation temperatures (20, 24, and 27 degrees C) and water content in the medium (20, 30, and 40%) influenced both volatile compounds formation and ochratoxin A biosynthesis efficiency, although conditions providing the maximum amount of volatiles were different from those providing the maximum amount of ochratoxin A. The pattern of volatiles produced by toxigenic A. ochraceus strains does not facilitate their differentiation from nontoxigenic strains.

Production of Conjugated Linoleic and Conjugated α-Linolenic Acid in a Reconstituted Skim Milk-Based Medium by Bifidobacterial Strains Isolated from Human Breast Milk

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María Antonia Villar-Tajadura

2014-01-01

Full Text Available Eight bifidobacterial strains isolated from human breast milk have been tested for their abilities to convert linoleic acid (LA and α-linolenic acid (LNA to conjugated linoleic acid (CLA and conjugated α-linolenic acid (CLNA, respectively. These bioactive lipids display important properties that may contribute to the maintenance and improvement human health. Three selected Bifidobacterium breve strains produced CLA from LA and CLNA from LNA in MRS (160–170 and 210–230 μg mL−1, resp. and, also, in reconstituted skim milk (75–95 and 210–244 μg mL−1, resp.. These bifidobacterial strains were also able to simultaneously produce both CLA (90–105 μg mL−1 and CLNA (290–320 μg mL−1 in reconstituted skim milk. Globally, our findings suggest that these bifidobacterial strains are potential candidates for the design of new fermented dairy products naturally containing very high concentrations of these bioactive lipids. To our knowledge, this is the first study describing CLNA production and coproduction of CLA and CLNA by Bifidobacterium breve strains isolated from human milk in reconstituted skim milk.

Feed Supplementation with Thermo-Tolerant, Lactic Acid-Producing Bacteria as Probiotics for Swine Husbandry

International Nuclear Information System (INIS)

Tongpim, Saowanit; Khammeng, Terdsak; Luanthisong, Pirat; Sakai, Kenji; Piadang, Nattayana

2006-09-01

This research work had an objective to employ the thermo tolerant, lactic acid-producing bacteria, Bacillus coagulans strain NF 1 7 as feed additive for swine raising. The bacterial isolate NF 1 7, kept in the culture collection of Khon Kaen University that could tolerate high temperature and produce lactic acid, was employed in this experiment. Cell suspension of isolate NF 1 7 was exposed to gamma irradiation at various doses (1-5 KGy). The isolated survivors were screened on the basis of forming larger colonies and clear zones than the parent strain NF 1 7 when grown on Glucose- Yeast extract-Peptone (GYP) containing CaCO 3 . We obtained 55 effective isolates which the isolate L 5 I2 to 14(5), designated as K 1 4 was chosen for further experiments. Isolate K 1 4 together with the parent strain were characterized using morphological, physiological and biochemical tests. They were all identified as Bacillus coagulans. All isolates had optimal growth pH of 6.5 and grew best at 42.50 o C. The strain K 1 4 could tolerate the temperature as high as 59 o C and was then employed in the fermentation of food waste that collected from the university cafeteria. It was found that food waste could support growth of Bacillus K 1 4 and produce about 107 to 108 CFU/g food waste within 1-3 days. Nutritional value of the fermented food waste in the form of protein was also increased. When mixing this selected bacterium as feed additive in daily pig rations, it was found that Bacillus K 1 4 helped increase feed conversion ratio and reduced the mortality in weaned piglets. Experiments were also performed with the growing pigs. It showed that Bacillus Sp. K 1 4 significantly improved the feed conversion ratio

Supplementary Material for: In silico screening for candidate chassis strains of free fatty acid-producing cyanobacteria

KAUST Repository

Motwalli, Olaa Amin; Essack, Magbubah; Jankovic, Boris R.; Ji, Boyang; Liu, Xinyao; Ansari, Hifzur; Hoehndorf, Robert; Gao, Xin; Arold, Stefan T.; Mineta, Katsuhiko; Archer, John; Gojobori, Takashi; Mijakovic, Ivan; Bajic, Vladimir B.

2017-01-01

Abstract Background Finding a source from which high-energy-density biofuels can be derived at an industrial scale has become an urgent challenge for renewable energy production. Some microorganisms can produce free fatty acids (FFA) as precursors

Draft Genome Sequence of a Clostridium botulinum Isolate from Water Used for Cooling at a Plant Producing Low-Acid Canned Foods.

Science.gov (United States)

Basavanna, Uma; Gonzalez-Escalona, Narjol; Timme, Ruth; Datta, Shomik; Schoen, Brianna; Brown, Eric W; Zink, Donald; Sharma, Shashi K

2013-01-01

Clostridium botulinum is a pathogen of concern for low-acid canned foods. Here we report draft genomes of a neurotoxin-producing C. botulinum strain isolated from water samples used for cooling low-acid canned foods at a canning facility. The genome sequence confirmed that this strain belonged to C. botulinum serotype B1, albeit with major differences, including thousands of unique single nucleotide polymorphisms (SNPs) compared to other genomes of the same serotype.

Draft Genome Sequence of a Clostridium botulinum Isolate from Water Used for Cooling at a Plant Producing Low-Acid Canned Foods

OpenAIRE

Basavanna, Uma; Gonzalez-Escalona, Narjol; Timme, Ruth; Datta, Shomik; Schoen, Brianna; Brown, Eric W.; Zink, Donald; Sharma, Shashi K.

2013-01-01

Clostridium botulinum is a pathogen of concern for low-acid canned foods. Here we report draft genomes of a neurotoxin-producing C.?botulinum strain isolated from water samples used for cooling low-acid canned foods at a canning facility. The genome sequence confirmed that this strain belonged to C.?botulinum serotype B1, albeit with major differences, including thousands of unique single nucleotide polymorphisms (SNPs) compared to other genomes of the same serotype.

Fusidic acid resistance among staphylococci strains isolated from clinical specimens

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Özcan Deveci

2012-03-01

Full Text Available Objectives: The aim of this study was to investigate in vitrosusceptibility of fusidic acid to clinic isolates of staphylococci.Materials and methods: The forty-one coagulase negativestaphylococci (CNS and 18 Staphylococcus aureusstrains isolated from various clinical specimens were includedin this study. Staphylococci isolates were identifiedby conventional methods such as colony morphologyonto medium, gram staining, catalase and coagulasetests. According to “Clinical and Laboratory Standards Institute(CLSI” criteria, antimicrobial susceptibility testingof isolates was performed by Kirby-Bauer’s disk diffusionmethod.Results: The seventy-two percent of the isolated S.aureuswere defined as methicillin sensitive-S.aureus (MSSA,28% of the isolated S.aureus were defined as methicillinresistant-S.aureus (MRSA. The difference among fusidicacid susceptibility rates of MSSA and MRSA strains wasnot statistically significant (p=0.305. The twenty-nine percentof the isolated CNS were defined as methicillin sensitive-CNS (MS-CNS, 71% of the isolated CNS were definedas methicillin resistant-CNS (MR-CNS. There wasno statistically significant difference between MS-CNSand MR-CNS strains for fusidic acid susceptibility rates(p=0.490. But the difference among fusidic acid susceptibilityrates of CNS and S.aureus strains was statisticallysignificant (p<0.001. CNS strains were found more resistancethan S.aureus strains for fusidic acid.Conclusion: In this study, the resistance rates weredetected to increase for fusidic acid along with methicillinresistance. Among CNS isolates, fusidic acid resistancerates were significantly more elevated than that forS.aureus. Fusidic acid remains as an alternative in thetreatment of infections due to staphylococci.

Overexpression of the NADP+-specific isocitrate dehydrogenase gene (icdA) in citric acid-producing Aspergillus niger WU-2223L.

Science.gov (United States)

Kobayashi, Keiichi; Hattori, Takasumi; Hayashi, Rie; Kirimura, Kohtaro

2014-01-01

In the tricarboxylic acid (TCA) cycle, NADP(+)-specific isocitrate dehydrogenase (NADP(+)-ICDH) catalyzes oxidative decarboxylation of isocitric acid to form α-ketoglutaric acid with NADP(+) as a cofactor. We constructed an NADP(+)-ICDH gene (icdA)-overexpressing strain (OPI-1) using Aspergillus niger WU-2223L as a host and examined the effects of increase in NADP(+)-ICDH activity on citric acid production. Under citric acid-producing conditions with glucose as the carbon source, the amounts of citric acid produced and glucose consumed by OPI-1 for the 12-d cultivation period decreased by 18.7 and 10.5%, respectively, compared with those by WU-2223L. These results indicate that the amount of citric acid produced by A. niger can be altered with the NADP(+)-ICDH activity. Therefore, NADP(+)-ICDH is an important regulator of citric acid production in the TCA cycle of A. niger. Thus, we propose that the icdA gene is a potentially valuable tool for modulating citric acid production by metabolic engineering.

New rifamycins produced by a recombinant strain of Nocardia mediterranei.

Science.gov (United States)

Schupp, T; Traxler, P; Auden, J A

1981-08-01

A recombinant strain of Nocardia mediterranei was found to produce a number of new rifamycins which are structurally related to rifamycin S, rifamycin W and rifamycin G. This strain was derived from two Nocardia mediterranei mutants by intraspecific recombination.

Continuous cultivations of a Penicillium chrysogenum strain expressing the expandase gene from Streptomyces clavuligerus: Kinetics of adipoyl-7-aminodeacetoxycephalosporanic acid and byproduct formations

DEFF Research Database (Denmark)

Robin, Jarno Jacky Christian; Bruheim, P.; Nielsen, M.L.

2003-01-01

The production kinetics of a transformed strain of Penicillium chrysogenum expressing the expandase gene from Streptomyces clavuligerus was investigated in chemostat cultivations. The recombinant strain produces adipoyl-7-aminodeacetoxycephalosporanic acid (ad-7-ADCA) as the major product; however...

A new highly productive Propionibacterium acidipropionici FL-48 strain with increased resistance to propionic acid and the scaling up of its production for industrial bioreactors

Directory of Open Access Journals (Sweden)

M. A. Kartashov

2016-09-01

Full Text Available Propionic acid bacteria, including Propionibacterium acidipropionici, are widely used in the chemical industry to produce propionic acid and also for food and feed preservation. However, the efficiency of the industrial production of these bacteria is limited by their sensitivity to high concentrations of propionic acid excreted into the cultivation medium. Therefore, the development of new biotechnological processes and strains able to overcome this limitation and to improve the profitability of the microbiological production remains  a relevant problem. A new P. acidipropionici FL-48 strain characterized by an increased resistance to 10 g/L of propionic acid (the number of viable cells after 24-h cultivation reached 1.05 × 106 was developed by a two-step induced mutagenesis using UV and diethyl sulphate from the P. acidipropionici VKPM B-5723 strain. The mutant strain exceeded the parental strain in the biomass accumulation rate and the amount of produced propionic and acetic acids by 35%, 20%, and 16%, respectively. The stability of such important characteristics as the biomass accumulation rate and the viability on media containing heightened concentrations of propionic acid was confirmed by three sequential monoclonal subculturings on a medium supplemented with 10 g/L of propionic acid. The optimization of the cultivation technology made it possible to determine the optimum seed inoculum dose (10% of the fermentation medium volume and the best pH level for the active growth stage (6.1 ± 0.1. The scaling up of the fermentation to a 100-L bioreactor under observance of optimum cultivation conditions demonstrated a high biomass growth rate with a sufficient reproducability; after 20 h of fermentation, the number of viable cells in the culture broth exceeded 1 × 1010 CFU/mL. The new strain could be interesting as the component of silage and haylage biopreservatives and also could be used as an efficient producer of propionic acid.

Screening and characterization of Lactobacillus strains producing large amounts of exopolysaccharides

NARCIS (Netherlands)

Geel-Schutten, G.H. van; Flesch, F.; Brink, B. ten; Smith, M.R.; Dijkhuizen, L.

1998-01-01

A total of 182 Lactobacillus strains were screened for production of extracellular polysaccharides (EPS) by a new method: growth in liquid media with high sugar concentrations. Sixty EPS-positive strains were identified; 17 strains produced more than 100 mg/l soluble EPS. Sucrose was an excellent

Efficacy of Peracetic Acid in Inactivating Foodborne Pathogens on Fresh Produce Surface.

Science.gov (United States)

Singh, Prashant; Hung, Yen-Con; Qi, Hang

2018-02-01

Washing treatment with effective sanitizer is one of the critical steps in ensuring fresh produce safety. This study was to evaluate the efficacy of peracetic acid (PAA; VigorOx® 15 F&V), chlorine-based sanitizers (acidic electrolyzed water [AEO], near neutral electrolyzed water and bleach), lactic acid, and deionized (DI) water to reduce Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium DT104 from fresh produce surfaces. A 5-strain cocktail of E. coli O157:H7, L. monocytogenes, and S. Typhimurium DT104 was separately prepared and used for surface inoculation on produce samples (E. coli O157:H7 on romaine lettuce, lemons, tomatoes, and blueberries; L. monocytogenes on romaine lettuce and cantaloupe; S. Typhimurium DT104 on lemons, tomatoes, cantaloupe, and blueberries). PAA at 45, 85, and 100 mg/L; AEO, NNEO, and bleach at 100 mg/L of free chlorine; lactic acid at 2%; and DI water were used for washing inoculated produce in an automated produce washer for 5 min. In general, PAA at 100 mg/L achieved the highest microbial inactivation of E. coli O157:H7 (lettuce, lemon, tomato, and blueberry at 2.2, 5.7, 5.5, and 6.7 log CFU/g, respectively), S. Typhimurium DT104 (lemon, tomato, cantaloupe, blueberry at 5.4, 6.8, 4.5, and 5.9 log CFU/g, respectively), and L. monocytogenes (lettuce and cantaloupe at 2.4 and 4.4 log CFU/g, respectively). Efficacy of sanitizers on produce with coarse surface (for example, lettuce and cantaloupe) was lower than produce with smooth texture (lemon, tomato, and blueberry). Cross-contamination of E. coli O157:H7 among romaine lettuce heads during simulated retail crisping process was greatly reduced by the application of PAA and NNEO. NNEO and PAA showed high efficacy in foodborne pathogen removal from fresh produce. Produce surface texture plays an important role in pathogen removal. NNEO and PAA effectively prevented cross-contamination during the crisping process. © 2018 Institute of Food Technologists®.

Ninety six well microtiter plate as microbioreactors for production of itaconic acid by six Aspergillus terreus strains

Science.gov (United States)

Itaconic acid (IA) is a building block platform chemical that is currently produced industrially from glucose by fermentation with Aspergillus terreus. However, lignocellulosic biomass has the potential to serve as low cost source of sugars for production of IA. Previously, 100 A. terreus strains we...

Isolation and characterization of large spectrum and multiple bacteriocin-producing Enterococcus faecium strain from raw bovine milk.

Science.gov (United States)

Gaaloul, N; ben Braiek, O; Hani, K; Volski, A; Chikindas, M L; Ghrairi, T

2015-02-01

To assess the antimicrobial properties of lactic acid bacteria from Tunisian raw bovine milk. A bacteriocin-producing Enterococcus faecium strain was isolated from raw cow milk with activity against Gram-positive and Gram-negative bacteria. Antimicrobial substances produced by this strain were sensitive to proteolytic enzymes and were thermostable and resistant to a broad range of pH (2-10). Mode of action of antimicrobial substances was determined as bactericidal. Maximum activity was reached at the end of the exponential growth phase when checked against Listeria ivanovii BUG 496 (2366.62 AU ml(-1)). However, maximum antimicrobial activity against Pseudomonas aeruginosa 28753 was recorded at the beginning of the exponential growth phase. Enterococcus faecium GGN7 was characterized as free from virulence factors and was susceptible to tested antibiotics. PCR analysis of the micro-organism's genome revealed the presence of genes coding for enterocins A and B. Mass spectrometry analysis of RP-HPLC active fractions showed molecular masses corresponding to enterocins A (4835.77 Da) and B (5471.56 Da), and a peptide with a molecular mass of 3215.5 Da active only against Gram-negative indicator strains. The latter was unique in the databases. Enterococcus faecium GGN7 produces three bacteriocins with different inhibitory spectra. Based on its antimicrobial properties and safety, Ent. faecium GGN7 is potentially useful for food biopreservation. The results suggest the bacteriocins from GGN7 strain could be useful for food biopreservation. © 2014 The Society for Applied Microbiology.

NEW STRAINS PRODUCER OF BIOBUTANOL. ІІ. RENEWABLE LIGNOCELLULOSE FERMENTATION

Directory of Open Access Journals (Sweden)

Tigunova O. O.

2014-08-01

Full Text Available The purpose of our work was to study generic and specific affinity of domestic strainsproducers, comparative productivity butanol strains-producers screening, fermentation of sugars being a part of renewable lignocelluloses raw materials and to determine the conditions for the butanol yield increasing. The objects of research were strains Clostridium acetobutylicum ІМВ В-7407 (IFBG C6H, IFBG C4B and IFBG C7P from «Collection microorganism’s stains and plants line for food and agriculture biotechnology» of Institute of Food Biotechnology and Genomics of the National Academy of Sciences of Ukraine. It was determined that domestic butanol-producing strains were relatively more productive and might be promising for improvement technology of butanol production.

[Morphological characteristics and physiological properties of aflatoxin B1 producing and non-producing Aspergillus flavus strains].

Science.gov (United States)

Kogbo, W; Lemarinier, S; Boutibonnes, P

1985-09-01

Comparison between about 80 strains of Aspergillus flavus, belonging to the series flavus and oryzae, obtained from international collections but also isolated from French or African substrates revealed the following observations: 1. Cultural and morphological characteristics of toxicogenic and atoxicogenic strains of A. flavus are similar. However, the former produce a diffusible yellow pigment in 83% of isolates. 2. The two groups of conidiospores have the same resistance to UV irradiation (254 nm, 5 and 10 min). All the strains are equally sensitive to 4 antifungal antibiotics: nystatine, ketoconazole, clotrimazole and amphotericine. 3. A difference was seen in the capacity to produce enzymes as alpha-galactosidase, beta-galactosidase and beta-glucosidase, implicated in the glucid metabolism. The specific hydrolytic activity has been confirmed by the characterization of a large amount of beta-galactosidase and by a diauxic growth on glucose medium supplemented by lactose. Possible relationship between these characters and aflatoxin B1 production by A. flavus strains is discussed.

Isolation and identification of a thermophilic strain producing trehalose synthase from geothermal water in China.

Science.gov (United States)

Zhu, Yueming; Zhang, Jun; Wei, Dongsheng; Wang, Yufan; Chen, Xiaoyun; Xing, Laijun; Li, Mingchun

2008-08-01

A slightly thermophilic strain, CBS-01, producing trehalose synthase (TreS), was isolated from geothermal water in this study. According to the phenotypic characteristics and phylogenetic analysis of the 16s rRNA gene sequence, it was identified as Meiothermus ruber. The trehalose synthase gene of Meiothermus ruber CBS-01 was cloned by polymerase chain reaction and sequenced. The TreS gene consisted of 2,895 nucleotides, which specified a 964-amino-acid protein. This novel TreS catalyzed reversible interconversion of maltose and trehalose.

[Distiller Yeasts Producing Antibacterial Peptides].

Science.gov (United States)

Klyachko, E V; Morozkina, E V; Zaitchik, B Ts; Benevolensky, S V

2015-01-01

A new method of controlling lactic acid bacteria contamination was developed with the use of recombinant Saccharomyces cerevisiae strains producing antibacterial peptides. Genes encoding the antibacterial peptides pediocin and plantaricin with codons preferable for S. cerevisiae were synthesized, and a system was constructed for their secretory expression. Recombinant S. cerevisiae strains producing antibacterial peptides effectively inhibit the growth of Lactobacillus sakei, Pediacoccus pentasaceus, Pediacoccus acidilactici, etc. The application of distiller yeasts producing antibacterial peptides enhances the ethanol yield in cases of bacterial contamination. Recombinant yeasts producing the antibacterial peptides pediocin and plantaricin can successfully substitute the available industrial yeast strains upon ethanol production.

Nutritional enrichment of larval fish feed with thraustochytrid producing polyunsaturated fatty acids and xanthophylls.

Science.gov (United States)

Yamasaki, Takashi; Aki, Tsunehiro; Mori, Yuhsuke; Yamamoto, Takeki; Shinozaki, Masami; Kawamoto, Seiji; Ono, Kazuhisa

2007-09-01

In marine aquaculture, rotifers and Artemia nauplii employed as larval fish feed are often nutritionally enriched with forage such as yeast and algal cells supplemented with polyunsaturated fatty acids and xanthophylls, which are required for normal growth and a high survival ratio of fish larvae. To reduce the enrichment steps, we propose here the use of a marine thraustochytrid strain, Schizochytrium sp. KH105, producing docosahexaenoic acid, docosapentaenoic acid, canthaxanthin, and astaxanthin. The KH105 cells prepared by cultivation under optimized conditions were successfully incorporated by rotifers and Artemia nauplii. The contents of docosahexaenoic acid surpassed the levels required in feed for fish larvae, and the enriched Artemia showed an increased body length. The results demonstrate that we have developed an improved method of increasing the dietary value of larval fish feed.

Bacillus coagulans MA-13: a promising thermophilic and cellulolytic strain for the production of lactic acid from lignocellulosic hydrolysate.

Science.gov (United States)

Aulitto, Martina; Fusco, Salvatore; Bartolucci, Simonetta; Franzén, Carl Johan; Contursi, Patrizia

2017-01-01

The transition from a petroleum-based economy towards more sustainable bioprocesses for the production of fuels and chemicals (circular economy) is necessary to alleviate the impact of anthropic activities on the global ecosystem. Lignocellulosic biomass-derived sugars are suitable alternative feedstocks that can be fermented or biochemically converted to value-added products. An example is lactic acid, which is an essential chemical for the production of polylactic acid, a biodegradable bioplastic. However, lactic acid is still mainly produced by Lactobacillus species via fermentation of starch-containing materials, the use of which competes with the supply of food and feed. A thermophilic and cellulolytic lactic acid producer was isolated from bean processing waste and was identified as a new strain of Bacillus coagulans , named MA-13. This bacterium fermented lignocellulose-derived sugars to lactic acid at 55 °C and pH 5.5. Moreover, it was found to be a robust strain able to tolerate high concentrations of hydrolysate obtained from wheat straw pre-treated by acid-catalysed (pre-)hydrolysis and steam explosion, especially when cultivated in controlled bioreactor conditions. Indeed, unlike what was observed in microscale cultivations (complete growth inhibition at hydrolysate concentrations above 50%), B. coagulans MA-13 was able to grow and ferment in 95% hydrolysate-containing bioreactor fermentations. This bacterium was also found to secrete soluble thermophilic cellulases, which could be produced at low temperature (37 °C), still retaining an optimal operational activity at 50 °C. The above-mentioned features make B. coagulans MA-13 an appealing starting point for future development of a consolidated bioprocess for production of lactic acid from lignocellulosic biomass, after further strain development by genetic and evolutionary engineering. Its optimal temperature and pH of growth match with the operational conditions of fungal enzymes hitherto

Purification and amino acid sequence of a bacteriocins produced by Lactobacillus salivarius K7 isolated from chicken intestine

Directory of Open Access Journals (Sweden)

Kenji Sonomoto

2006-03-01

Full Text Available A bacteriocin-producing strain, Lactobacillus K7, was isolated from a chicken intestine. The inhibitory activity was determined by spot-on-lawn technique. Identification of the strain was performed by morphological, biochemical (API 50 CH kit and molecular genetic (16S rDNA basis. Bacteriocin purification processes were carried out by amberlite adsorption, cation exchange and reverse-phase high perform- ance liquid chromatography. N-terminal amino acid sequences were performed by Edman degradation. Molecular mass was determined by electrospray-ionization (ESI mass spectrometry (MS. Lactobacillus K7 showed inhibitory activity against Lactobacillus sakei subsp. sakei JCM 1157T, Leuconostoc mesenteroides subsp. mesenteroides JCM 6124T and Bacillus coagulans JCM 2257T. This strain was identified as Lb. salivarius. The antimicrobial substance was destroyed by proteolytic enzymes, indicating its proteinaceous structure designated as a bacteriocin type. The purification of bacteriocin by amberlite adsorption, cation exchange, and reverse-phase chromatography resulted in only one single active peak, which was designated FK22. Molecular weight of this fraction was 4331.70 Da. By amino acid sequence, this peptide was homology to Abp 118 beta produced by Lb. salivarius UCC118. In addition, Lb. salivarius UCC118 produced 2-peptide bacteriocin, which was Abp 118 alpha and beta. Based on the partial amino acid sequences of Abp 118 beta, specific primers were designed from nucleotide sequences according to data from GenBank. The result showed that the deduced peptide was high homology to 2-peptide bacteriocin, Abp 118 alpha and beta.

Feed Supplementation with Thermo-Tolerant, Lactic Acid-Producing Bacteria as Probiotics for Swine Husbandry

Energy Technology Data Exchange (ETDEWEB)

Tongpim, Saowanit [Dept. of Microbiology, Fac. of Science, Khon Kaen Univ., Khon Kaen (Thailand); Khammeng, Terdsak [Dept. of Animal Science, Fac. of Agriculture, Khon kaen Univ., Khon kaen (Thailand); Luanthisong, Pirat [Rajamangala Univ., of Technology Isan, Karasin Campus, Karasin (Thailand); Sakai, Kenji [Dept. of Agricultural Chemistry, Fac. of Engineering, Oita Univ., Oita (Japan); Piadang, Nattayana [Office of Atoms for Peace, Bangkok (Thailand)

2006-09-15

This research work had an objective to employ the thermo tolerant, lactic acid-producing bacteria, Bacillus coagulans strain NF{sub 1}7 as feed additive for swine raising. The bacterial isolate NF{sub 1}7, kept in the culture collection of Khon Kaen University that could tolerate high temperature and produce lactic acid, was employed in this experiment. Cell suspension of isolate NF{sub 1}7 was exposed to gamma irradiation at various doses (1-5 KGy). The isolated survivors were screened on the basis of forming larger colonies and clear zones than the parent strain NF{sub 1}7 when grown on Glucose- Yeast extract-Peptone (GYP) containing CaCO{sub 3}. We obtained 55 effective isolates which the isolate L{sub 5}I2 to 14(5), designated as K{sub 1}4 was chosen for further experiments. Isolate K{sub 1}4 together with the parent strain were characterized using morphological, physiological and biochemical tests. They were all identified as Bacillus coagulans. All isolates had optimal growth pH of 6.5 and grew best at 42.50 {sup o}C. The strain K{sub 1}4 could tolerate the temperature as high as 59 {sup o}C and was then employed in the fermentation of food waste that collected from the university cafeteria. It was found that food waste could support growth of Bacillus K{sub 1}4 and produce about 107 to 108 CFU/g food waste within 1-3 days. Nutritional value of the fermented food waste in the form of protein was also increased. When mixing this selected bacterium as feed additive in daily pig rations, it was found that Bacillus K{sub 1}4 helped increase feed conversion ratio and reduced the mortality in weaned piglets. Experiments were also performed with the growing pigs. It showed that Bacillus Sp. K{sub 1}4 significantly improved the feed conversion ratio

Selection of the Strain Lactobacillus acidophilus ATCC 43121 and Its Application to Brewers' Spent Grain Conversion into Lactic Acid

Science.gov (United States)

Liguori, Rossana; Soccol, Carlos Ricardo; Vandenberghe, Luciana Porto de Souza; Woiciechowski, Adenise Lorenci; Ionata, Elena; Marcolongo, Loredana; Faraco, Vincenza

2015-01-01

Six Lactobacillus strains were analyzed to select a bacterium for conversion of brewers' spent grain (BSG) into lactic acid. Among the investigated strains, L. acidophilus ATCC 43121 showed the highest yield of lactic acid production (16.1 g/L after 48 hours) when grown in a synthetic medium. It was then analyzed for its ability to grow on the hydrolysates obtained from BSG after acid-alkaline (AAT) or aqueous ammonia soaking (AAS) pretreatment. The lactic acid production by L. acidophilus ATCC 43121 through fermentation of the hydrolysate from AAS treated BSG was 96% higher than that from the AAT treated one, although similar yields of lactic acid per consumed glucose were achieved due to a higher (46%) glucose consumption by L. acidophilus ATCC 43121 in the AAS BSG hydrolysate. It is worth noting that adding yeast extract to the BSG hydrolysates increased both the yield of lactic acid per substrate consumed and the volumetric productivity. The best results were obtained by fermentation of AAS BSG hydrolysate supplemented by yeast extract, in which the strain produced 22.16 g/L of lactic acid (yield of 0.61 g/g), 27% higher than the value (17.49 g/L) obtained in the absence of a nitrogen source. PMID:26640784

Quantitative and qualitative determination of CLA produced by bifidobacterium and lactic acid bacteria by combining spectrophotometric and Ag+-HPLC techniques

OpenAIRE

Rodríguez-Alcalá, Luis M.; Braga, Teresa; Malcata, F. Xavier; Gomes, Ana; Fontecha, Javier

2011-01-01

Bifidobacterium and lactic acid bacteria (LAB), especially from the genera Lactobacillus and Lactococcus, are commonly used in the production of fermented dairy products due to their potential probiotic characteristics. Moreover, some strains of these microorganisms also have the ability to produce conjugated linoleic acid (CLA) from linoleic acid (LA), which has attracted much attention as a novel type of beneficial functional fermented milk. In the present work 22 probiotic bact...

A cost-effective approach to produce 15N-labelled amino acids employing Chlamydomonas reinhardtii CC503.

Science.gov (United States)

Nicolás Carcelén, Jesús; Marchante-Gayón, Juan Manuel; González, Pablo Rodríguez; Valledor, Luis; Cañal, María Jesús; Alonso, José Ignacio García

2017-08-18

The use of enriched stable isotopes is of outstanding importance in chemical metrology as it allows the application of isotope dilution mass spectrometry (IDMS). Primary methods based on IDMS ensure the quality of the analytical measurements and traceability of the results to the international system of units. However, the synthesis of isotopically labelled molecules from enriched stable isotopes is an expensive and a difficult task. Either chemical and biochemical methods to produce labelled molecules have been proposed, but so far, few cost-effective methods have been described. The aim of this study was to use the microalgae Chlamydomonas reinhardtii to produce, at laboratory scale, 15 N-labelled amino acids with a high isotopic enrichment. To do that, a culture media containing 15 NH 4 Cl was used. No kinetic isotope effect (KIE) was observed. The labelled proteins biosynthesized by the microorganism were extracted from the biomass and the 15 N-labelled amino acids were obtained after a protein hydrolysis with HCl. The use of the wall deficient strain CC503 cw92 mt+ is fit for purpose, as it only assimilates ammonia as nitrogen source, avoiding isotope contamination with nitrogen from the atmosphere or the reagents used in the culture medium, and enhancing the protein extraction efficiency compared to cell-walled wild type Chlamydomonas. The isotopic enrichment of the labelled amino acids was calculated from their isotopic composition measured by gas chromatography mass spectrometry (GC-MS). The average isotopic enrichment for the 16 amino acids characterized was 99.56 ± 0.05% and the concentration of the amino acids in the hydrolysate ranged from 18 to 90 µg/mL. Previously reported biochemical methods to produce isotopically labelled proteins have been applied in the fields of proteomics and fluxomics. For these approaches, low amounts of products are required and the isotopic enrichment of the molecules has never been properly determined. So far, only 13

Clostridium botulinum strains producing BoNT/F4 or BoNT/F5.

Science.gov (United States)

Raphael, Brian H; Bradshaw, Marite; Kalb, Suzanne R; Joseph, Lavin A; Lúquez, Carolina; Barr, John R; Johnson, Eric A; Maslanka, Susan E

2014-05-01

Botulinum neurotoxin type F (BoNT/F) may be produced by Clostridium botulinum alone or in combination with another toxin type such as BoNT/A or BoNT/B. Type F neurotoxin gene sequences have been further classified into seven toxin subtypes. Recently, the genome sequence of one strain of C. botulinum (Af84) was shown to contain three neurotoxin genes (bont/F4, bont/F5, and bont/A2). In this study, eight strains containing bont/F4 and seven strains containing bont/F5 were examined. Culture supernatants produced by these strains were incubated with BoNT/F-specific peptide substrates. Cleavage products of these peptides were subjected to mass spectral analysis, allowing detection of the BoNT/F subtypes present in the culture supernatants. PCR analysis demonstrated that a plasmid-specific marker (PL-6) was observed only among strains containing bont/F5. Among these strains, Southern hybridization revealed the presence of an approximately 242-kb plasmid harboring bont/F5. Genome sequencing of four of these strains revealed that the genomic backgrounds of strains harboring either bont/F4 or bont/F5 are diverse. None of the strains analyzed in this study were shown to produce BoNT/F4 and BoNT/F5 simultaneously, suggesting that strain Af84 is unusual. Finally, these data support a role for the mobility of a bont/F5-carrying plasmid among strains of diverse genomic backgrounds.

Intraspecies cellular fatty acids heterogeneity of Lactobacillus plantarum strains isolated from fermented foods in Ukraine.

Science.gov (United States)

Garmasheva, I; Vasyliuk, O; Kovalenko, N; Ostapchuk, A; Oleschenko, L

2015-09-01

The intraspecies heterogeneity of cellular fatty acids composition of Lactobacillus plantarum strains isolated from Ukrainian traditional fermented foods was examined. Seven cellular fatty acids were identified. All Lact. plantarum strains investigated contained C16:0 (from 7·54 to 49·83% of total fatty acids), cC18:1 (3·23-38·67% of total fatty acids) and cycC19:0 acids (9·03-67·68% of total fatty acids) as the major fatty acids. The tC18:1 acid made up 1·47-22·0% of the total fatty acids. The C14:0 and C16:1 acids were present in small amounts (0·22-6·96% and 0·66-7·42% respectively) in most Lact. plantarum strains. Differences in relative contents of some fatty acids between Lact. plantarum strains depending on the source isolation were found. Isolates of dairy origin contained slightly greater levels of the C16:0 and tC18:1 fatty acids and lower levels of the cC18:1 than strains obtained from fermented vegetables. The origin of Lact. plantarum strains affects their fatty acids composition, which in turn, appears to be related to their ability to growth under stress factors. Cellular fatty acids composition is an important chemotaxonomic characteristic of bacterial cells. At the same time cellular fatty acids play a key role in maintaining the viability of micro-organisms in different environmental conditions. In this study, intraspecies heterogeneity of cellular fatty acids composition of Lactobacillus plantarum strains was examined. This work provides novel and important information about a relationship between cellular fatty acids composition of Lact. plantarum strains and source of isolation or stress resistance profile. Our results showed that cellular fatty acids composition is quite diverse among Lact. plantarum strains derived from different sources and may reflect previous cell's history. Our findings should be considered in chemotaxonomic studies of lactic acid bacteria and its ecology. © 2015 The Society for Applied Microbiology.

Comparison of the acidifying activity of Lactococcus lactis subsp. lactis strains isolated from goat's milk and Valdeteja cheese.

Science.gov (United States)

Alonso-Calleja, C; Carballo, J; Capita, R; Bernardo, A; García-López, M L

2002-01-01

This work was carried out to study the acid production by Lactococcus lactis subsp. lactis strains isolated from goat's milk and goat cheese (Valdeteja variety) in order to select a suitable starter culture for industrial goat cheese manufacturing. The titrable acidity of 45 Lactococcus lactis subsp. lactis strains isolated from a home-made batch of Valdeteja cheese with excellent sensory characteristics was measured over a period of 18 h. The strains were divided into two groups depending on the acid production rate: 20 fast acid producer (F) strains and 25 slow acid producer (S) strains. The kinetic parameters (lag phase, maximum acid production rate and value of upper asymptote curve) of the acid production curves for F and S strains were significantly (P titrable acidity of F and S strains were observed after the second hour of incubation. An F strain acetoin producer (Lactococcus lactis subsp. lactis 470Ch2) was selected as autochthonous starter culture for industrial Valdeteja goat cheese manufacturing.

Lichenysin is produced by most Bacillus licheniformis strains.

Science.gov (United States)

Madslien, E H; Rønning, H T; Lindbäck, T; Hassel, B; Andersson, M A; Granum, P E

2013-10-01

The aim of this study was to elucidate the prevalence of lichenysin production in Bacillus licheniformis and to see whether this feature was restricted to certain genotypes. Secondly, we wanted to see whether cytotoxicity reflected the measured levels of lichenysin. Fifty-three genotyped strains of B. licheniformis, representing a wide variety of sources, were included. lchAA gene fragments were detected in all strains by polymerase chain reaction (PCR). All 53 strains produced lichenysins with four molecular masses as confirmed by LC-MS/MS (liquid chromatography-tandem mass spectrometry) analysis. The amounts of lichenysin varied more than two orders of magnitude between strains and were irrespective of genotype. Finally, there was a strong association between lichenysin concentrations and toxicity towards boar spermatozoa, erythrocytes and Vero cells. Lichenysin synthesis was universal among the 53 B. licheniformis strains examined. The quantities varied considerably between strains, but were not specifically associated with genotype. Cytotoxicity was evident at lichenysin concentrations above 10 μg ml(-1) , which is in accordance with previous studies. This study might be of interest to those working on B. licheniformis for commercial use as well as for authorities who make risk assessments of B. licheniformis when used as a food and feed additive. © 2013 The Society for Applied Microbiology.

Identification of exopolysaccharides-producing lactic acid bacteria ...

African Journals Online (AJOL)

Spacer region between 16S and 23 S rRNA genes of thirteen lactic acid bacteria strains from Burkina Faso fermented milk samples were amplified by the polymerase chain reaction (PCR). Lactobacillus delbrueckii, Lactobacillus acidophilus, Lactobacillus fermentum, Streptococcus thermophilus, Pediococcus spp, ...

Screening of Gibberellic Acid Production by Pseudomonas SPP

International Nuclear Information System (INIS)

Khine Zar Wynn Myint; Khin Mya Lwin; Myo Myint

2010-12-01

The microbial gibberellic acid (GA3) production of Pseudomonas spp., was studied and qualitatively indentified by UV spectrophotometer. 20 strains of Pseudomonas spp., were isolated and screened the gibberellic acid productivily in King's B medium. Among them, only four strains can produce microbial gibberellic acid. The Rf values and colour appearance under UV were the same as authentic gibberellic acid. Moreover, the gibberellic acid producer strains were identified as Pseudomonas spp., by cultural, biochemical and drug sensitivity pattern.

Butyric acid fermentation from pre-treated wheat straw by a mutant clostridium tyrobutyricum strain

DEFF Research Database (Denmark)

Baroi, George Nabin; Baumann, Ivan; Westermann, Peter

Only little research on butyric acid fermentation has been carried out in relationship to bio-refinery perspectives involving strain selection, development of adapted strains, physiological analyses for higher yield, productivity and selectivity. However, a major step towards the development...... strain could grow in up to 80% pre-treated wheat straw and can ferment both glucose and xylose. The yield of butyric acid without optimization was 0,37±0,051 g butyric acid/g sugar monomers and the acetate yield was 0,06±0,021 g acetic acid/g sugar monomers. Moreover, the strain could grow without...... addition of yeast extract. Further optimization of yield and productivity is under investigation....

Isolation and characterization of biosurfactant-producing Alcanivorax strains: hydrocarbon accession strategies and alkane hydroxylase gene analysis.

Science.gov (United States)

Olivera, Nelda L; Nievas, Marina L; Lozada, Mariana; Del Prado, Guillermo; Dionisi, Hebe M; Siñeriz, Faustino

2009-01-01

Biosurfactant-producing bacteria belonging to the genera Alcanivorax, Cobetia and Halomonas were isolated from marine sediments with a history of hydrocarbon exposure (Aristizábal and Gravina Peninsulas, Argentina). Two Alcanivorax isolates were found to form naturally occurring consortia with strains closely related to Pseudomonas putida and Microbacterium esteraromaticum. Alkane hydroxylase gene analysis in these two Alcanivorax strains resulted in the identification of two novel alkB genes, showing 86% and 60% deduced amino acid sequence identity with those of Alcanivorax sp. A-11-3 and Alcanivorax dieselolei P40, respectively. In addition, a gene homologous to alkB2 from Alcanivorax borkumensis was present in one of the strains. The consortium formed by this strain, Alcanivorax sp. PA2 (98.9% 16S rRNA gene sequence identity with A. borkumensis SK2(T)) and P. putida PA1 was characterized in detail. These strains form cell aggregates when growing as mixed culture, though only PA2 was responsible for biosurfactant activity. During exponential growth phase of PA2, cells showed high hydrophobicity and adherence to hydrocarbon droplets. Biosurfactant production was only detectable at late growth and stationary phases, suggesting that it is not involved in initiating oil degradation and that direct interfacial adhesion is the main hydrocarbon accession mode of PA2. This strain could be useful for biotechnological applications due to its biosurfactant production, catabolic and aggregation properties.

Synergism between hydrogen peroxide and seventeen acids against six bacterial strains.

Science.gov (United States)

Martin, H; Maris, P

2012-09-01

The objective of this study was to evaluate the bactericidal efficacy of hydrogen peroxide administered in combination with 17 mineral and organic acids authorized for use in the food industry. The assays were performed on a 96-well microplate using a microdilution technique based on the checkerboard titration method. The six selected strains were reference strains and strains representative of contaminating bacteria in the food industry. Each synergistic hydrogen peroxide/acid combination found after 5-min contact time at 20°C in distilled water was then tested in conditions simulating four different use conditions. Thirty-two combinations were synergistic in distilled water; twenty-five of these remained synergistic with one or more of the four mineral and organic interfering substances selected. Hydrogen peroxide/formic acid combination was synergistic for all six bacterial strains in distilled water and remained synergistic with interfering substances. Six other combinations maintained their synergistic effect in the presence of an organic load but only for one or two bacterial strains. Synergistic combinations of disinfectants were revealed, among them the promising hydrogen peroxide/formic acid combination. A rapid screening method was proposed and used to reveal the synergistic potential of disinfectant and/or sanitizer combinations. © 2012 ANSES Fougères Laboratory Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

Quantitative analysis of fatty-acid-based biofuels produced by wild-type and genetically engineered cyanobacteria by gas chromatography-mass spectrometry.

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Guan, Wenna; Zhao, Hui; Lu, Xuefeng; Wang, Cong; Yang, Menglong; Bai, Fali

2011-11-11

Simple and rapid quantitative determination of fatty-acid-based biofuels is greatly important for the study of genetic engineering progress for biofuels production by microalgae. Ideal biofuels produced from biological systems should be chemically similar to petroleum, like fatty-acid-based molecules including free fatty acids, fatty acid methyl esters, fatty acid ethyl esters, fatty alcohols and fatty alkanes. This study founded a gas chromatography-mass spectrometry (GC-MS) method for simultaneous quantification of seven free fatty acids, nine fatty acid methyl esters, five fatty acid ethyl esters, five fatty alcohols and three fatty alkanes produced by wild-type Synechocystis PCC 6803 and its genetically engineered strain. Data obtained from GC-MS analyses were quantified using internal standard peak area comparisons. The linearity, limit of detection (LOD) and precision (RSD) of the method were evaluated. The results demonstrated that fatty-acid-based biofuels can be directly determined by GC-MS without derivation. Therefore, rapid and reliable quantitative analysis of fatty-acid-based biofuels produced by wild-type and genetically engineered cyanobacteria can be achieved using the GC-MS method founded in this work. Copyright © 2011 Elsevier B.V. All rights reserved.

Clostridium scatologenes strain SL1 isolated as an acetogenic bacterium from acidic sediments.

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Küsel, K; Dorsch, T; Acker, G; Stackebrandt, E; Drake, H L

2000-03-01

A strictly anaerobic, H2-utilizing bacterium, strain SL1, was isolated from the sediment of an acidic coal mine pond. Cells of strain SL1 were sporulating, motile, long rods with a multilayer cell wall. Growth was observed at 5-35 degrees C and pH 3.9-7.0. Acetate was the sole end product of H2 utilization and was produced in stoichiometries indicative of an acetyl-CoA-pathway-dependent metabolism. Growth and substrate utilization also occurred with CO/CO2, vanillate, syringate, ferulate, ethanol, propanol, 1-butanol, glycerine, cellobiose, glucose, fructose, mannose, xylose, formate, lactate, pyruvate and gluconate. With most substrates, acetate was the main or sole product formed. Growth in the presence of H2/CO2 or CO/CO2 was difficult to maintain in laboratory cultures. Methoxyl, carboxyl and acrylate groups of various aromatic compounds were O-demethylated, decarboxylated and reduced, respectively. Small amounts of butyrate were produced during the fermentation of sugars. The acrylate group of ferulate was reduced. Nitrate, sulfate, thiosulfate, dimethylsulfoxide and Fe(III) were not utilized as electron acceptors. Analysis of the 16S rRNA gene sequence of strain SL1 demonstrated that it is closely related to Clostridium scatologenes (99.6% sequence similarity), an organism characterized as a fermentative anaerobe but not previously shown to be capable of acetogenic growth. Comparative experiments with C. scatologenes DSM 757T demonstrated that it utilized H2/CO2 (negligible growth), CO/CO2 (negligible growth), formate, ethanol and aromatic compounds according to stoichiometries indicative of the acetyl-CoA pathway. CO dehydrogenase, formate dehydrogenase and hydrogenase activities were present in both strain SL1 and C. scatologenes DSM 757T. These results indicate that (i) sediments of acidic coal mine ponds harbour acetogens and (ii) C. scatologenes is an acetogen that tends to lose its capacity to grow acetogenically under H2/CO2 or CO/CO2 after prolonged

Usefulness of organic acid produced by Exiguobacterium sp. 12/1 on neutralization of alkaline wastewater.

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Kulshreshtha, Niha Mohan; Kumar, Anil; Bisht, Gopal; Pasha, Santosh; Kumar, Rita

2012-01-01

The aim of this study was to investigate the role of organic acids produced by Exiguobacterium sp. strain 12/1 (DSM 21148) in neutralization of alkaline wastewater emanated from beverage industry. This bacterium is known to be able to grow in medium of pH as high as pH 12.0 and to neutralize alkaline industrial wastewater from pH 12.0 to pH 7.5. The initial investigation on the type of functional groups present in medium, carried out using FT-IR spectroscopy, revealed the presence of peaks corresponding to carbonyl group and hydroxyl group, suggesting the release of carboxylic acid or related metabolic product(s). The identification of specific carboxylic group, carried out using RP-HPLC, revealed the presence of a single peak in the culture supernatant with retention time most similar to formic acid. The concentration of acid produced on different carbon sources was studied as a function of time. Although acid was present in same final concentration, the rate of acid production was highest in case of medium supplemented with sucrose followed by fructose and glucose. The knowledge of metabolic products of the bacterium can be considered as a first step towards realization of its potential for large-scale bioremediation of alkaline wastewater from beverage industry.

Usefulness of Organic Acid Produced by Exiguobacterium sp. 12/1 on Neutralization of Alkaline Wastewater

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Niha Mohan Kulshreshtha

2012-01-01

Full Text Available The aim of this study was to investigate the role of organic acids produced by Exiguobacterium sp. strain 12/1 (DSM 21148 in neutralization of alkaline wastewater emanated from beverage industry. This bacterium is known to be able to grow in medium of pH as high as pH 12.0 and to neutralize alkaline industrial wastewater from pH 12.0 to pH 7.5. The initial investigation on the type of functional groups present in medium, carried out using FT-IR spectroscopy, revealed the presence of peaks corresponding to carbonyl group and hydroxyl group, suggesting the release of carboxylic acid or related metabolic product(s. The identification of specific carboxylic group, carried out using RP-HPLC, revealed the presence of a single peak in the culture supernatant with retention time most similar to formic acid. The concentration of acid produced on different carbon sources was studied as a function of time. Although acid was present in same final concentration, the rate of acid production was highest in case of medium supplemented with sucrose followed by fructose and glucose. The knowledge of metabolic products of the bacterium can be considered as a first step towards realization of its potential for large-scale bioremediation of alkaline wastewater from beverage industry.

Antibacterial effect of roselle extracts (Hibiscus sabadariffa), sodium hypochlorite and acetic acid against multidrug-resistant Salmonella strains isolated from tomatoes.

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Gutiérrez-Alcántara, E J; Rangel-Vargas, E; Gómez-Aldapa, C A; Falfan-Cortes, R N; Rodríguez-Marín, M L; Godínez-Oviedo, A; Cortes-López, H; Castro-Rosas, J

2016-02-01

Antibiotic-resistant Salmonella strains were isolated from saladette and red round type tomatoes, and an analysis done of the antibacterial activity of roselle calyx extracts against any of the identified strains. One hundred saladette tomato samples and 100 red round tomato samples were collected from public markets. Each sample consisted of four whole tomatoes. Salmonella was isolated from the samples by conventional culture procedure. Susceptibility to 16 antibiotics was tested for the isolated Salmonella strains by standard test. The antibacterial effect of four roselle calyx extracts (water, methanol, acetone and ethyl acetate), sodium hypochlorite and acetic acid against antibiotic-resistant Salmonella isolates was evaluated on contaminated tomatoes. Twenty-four Salmonella strains were isolated from 12% of each tomato type. Identified Salmonella serotypes were Typhimurium and Typhi. All isolated strains exhibited resistance to at least three antibiotics and some to as many as 12. Over contaminated tomatoes, the roselle calyx extracts produced a greater reduction (2-2·6 log) in antibiotic-resistant Salmonella strain concentration than sodium hypochlorite and acetic acid. The presence of multidrug-resistant Salmonella in vegetables is a significant public health concern. Multidrug-resistant Salmonella strains were isolated from raw tomatoes purchased in public markets in Mexico and challenged with roselle Hibiscus sabdariffa calyx extracts, sodium hypochlorite and acetic acid. On tomatoes, the extracts caused a greater reduction in the concentration of antibiotic-resistant Salmonella strains than sodium hypochlorite and acetic acid. Roselle calyx extracts are a potentially useful addition to disinfection procedures of raw tomatoes in the field, processing plants, restaurants and homes. © 2015 The Society for Applied Microbiology.

Lipid composition in a strain of Bacillus subtilis, a producer of iturin A lipopeptides that are active against uropathogenic bacteria.

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Bernat, Przemysław; Paraszkiewicz, Katarzyna; Siewiera, Paulina; Moryl, Magdalena; Płaza, Grażyna; Chojniak, Joanna

2016-10-01

Urinary tract infections are a common disease in humans. Therefore, new methods are needed to destroy biofilms that are formed by uropathogens. Iturin A lipopeptides (LPs) C14 and C15 are potent biosurfactants synthetized by the Bacillus subtilis I'1a strain. The biological activity of extracted LPs was confirmed by examining extracts from I'1a cultures against uropathogenic bacteria that had been isolated from biofilms on urinary catheters. Compared with cultures of DSM 3257, which produce surfactin at a relatively low level, the extract obtained from strain I'1a exhibited a greater inhibitory effect against both planktonic and sessile forms of Escherichia coli, Serratia marcescens, Enterobacter cloacae, Proteus mirabilis, Citrobacter freundii and Enterococcus faecalis. Moreover, cyclic LP biosurfactants may disturb the integrity of cytoplasmic membranes; therefore, we investigated the effects of synthetized LPs on fatty acids and phospholipids of B. subtilis. LPs and lipids were analyzed using GC-MS, LC-MS/MS and MALDI-TOF/TOF techniques. Compared with B. subtilis DSM 3257, membranes of the I'1a strain were characterized by an increased amount of anteiso fatty acids and a ten-fold higher ratio of phosphatidylglycerol (PG)-to-phosphatidylethanolamine (PE). Interestingly, in cultures of B. subtilis DSM 3257 supplemented with LP extracts of the I'1a strain, the PG-to-PE ratio was fourfold higher, and the amount of anteiso fatty acids was also increased.

BIOCHEMICAL CHARACTERISTICS OF LACTIC ACID PRODUCING BACTERIA AND PREPARATION OF CAMEL MILK CHEESE BY USING STARTER CULTURE

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T. Ahmed and R. Kanwal

2004-04-01

Full Text Available Lactic acid bacteria (LAB were isolated from camel milk by culturing the milk on specific media and pure culture was obtained by sub-culturing. Purification of culture was confirmed by Gram’s staining and identified by different biochemical tests. Camel milk contained lactic acid producing bacteria like Streptococci such as S. cremoris and S. lactis and Lactobacilli such as L. acidophilus. L. acidophilus grew more rapidly in camel milk than others as its growth was supported by camel milk. Ability of each strain was tested to convert lactose of milk into lactic acid. It was observed that 66% lactose was converted by S. lactis 20, whereas S. cremoris 22 and L. acidophilus 23 converted 56 and 74% lactose into lactic acid, respectively. Effect of freeze-drying was also recorded and the results showed that in all cases there was a slight decrease in the cell count before and after the freeze-drying. The decrease was approximately 0.47, 0.078 and 0.86% for S. lactis 20, S. cremoris 22 and L. acidophilus 23, respectively. Starter culture was prepared from strains isolated from camel milk. Camel and buffalo milk cheese was prepared by using starter culture. The strains isolated from camel milk were best for acid production and coagulated the milk in less time. It is concluded that cheese can be prepared successfully from camel milk and better results can be obtained by coagulating milk with starter culture.

Identification and partial characterization of lactic acid bacteria isolated from traditional dairy products produced by herders in the western Tianshan Mountains of China.

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Zuo, F L; Feng, X J; Chen, L L; Chen, S W

2014-11-01

Thirty strains of lactic acid bacteria (LAB) were isolated from herders' traditional dairy products collected from Xinjiang, China. The species Lactobacillus, Lactococcus, Enterococcus, Pediococcus and Leuconostoc were identified by 16S ribosomal RNA gene sequencing analysis and conventional observation. The strains' fermentation characteristics, including milk acidification, proteolysis, autolysis, antimicrobial activity and diacetyl production, were assayed and compared. Strains NL24 and NL31 showed the highest proteolytic activity-2·75 and 2·08 mmol Phe l(-1) milk, respectively. Strains C, NL41, SW2, Z3-11, NL42 and Z2-91 had high autolytic activity. In addition, most of the wild strains produced diacetyl, half of them to high levels. This study provides a clue to LAB biodiversity in traditional dairy foods produced by herders in the western Tianshan Mountains. High-performing strains should be further evaluated for practical application in value-added fermented dairy products. Our results reveal a certain variety of lactic acid bacteria (LAB) in traditional dairy products from Xinjiang. Some of the LAB strains, such as Lactobacillus rhamnosus NL24 and Lactobacillus paracasei SW2, possess excellent functional properties and have the potential for application in indigenous fermented dairy products. Performance of the newly isolated strains in cheese or yogurt manufacturing was further evaluated. Application of the high-performing strains to enrich the flavour of fermented dairy products is highly desirable and holds great commercial potential. © 2014 The Society for Applied Microbiology.

A new class of IMP dehydrogenase with a role in self-resistance of mycophenolic acid producing fungi

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Mortensen Uffe H

2011-09-01

Full Text Available Abstract Background Many secondary metabolites produced by filamentous fungi have potent biological activities, to which the producer organism must be resistant. An example of pharmaceutical interest is mycophenolic acid (MPA, an immunosuppressant molecule produced by several Penicillium species. The target of MPA is inosine-5'-monophosphate dehydrogenase (IMPDH, which catalyses the rate limiting step in the synthesis of guanine nucleotides. The recent discovery of the MPA biosynthetic gene cluster from Penicillium brevicompactum revealed an extra copy of the IMPDH-encoding gene (mpaF embedded within the cluster. This finding suggests that the key component of MPA self resistance is likely based on the IMPDH encoded by mpaF. Results In accordance with our hypothesis, heterologous expression of mpaF dramatically increased MPA resistance in a model fungus, Aspergillus nidulans, which does not produce MPA. The growth of an A. nidulans strain expressing mpaF was only marginally affected by MPA at concentrations as high as 200 μg/ml. To further substantiate the role of mpaF in MPA resistance, we searched for mpaF orthologs in six MPA producer/non-producer strains from Penicillium subgenus Penicillium. All six strains were found to hold two copies of IMPDH. A cladistic analysis based on the corresponding cDNA sequences revealed a novel group constituting mpaF homologs. Interestingly, a conserved tyrosine residue in the original class of IMPDHs is replaced by a phenylalanine residue in the new IMPDH class. Conclusions We identified a novel variant of the IMPDH-encoding gene in six different strains from Penicillium subgenus Penicillium. The novel IMPDH variant from MPA producer P. brevicompactum was shown to confer a high degree of MPA resistance when expressed in a non-producer fungus. Our study provides a basis for understanding the molecular mechanism of MPA resistance and has relevance for biotechnological and pharmaceutical applications.

Enhancement in ex vivo phagocytic capacity of peritoneal leukocytes in mice by oral delivery of various lactic-acid-producing bacteria.

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Lee, Yeonhee; Lee, Taik-Soo

2005-01-01

Lactic-acid-producing bacteria (LABs) are known to have immunomodulating activity. In the current study, various LABs were tested for their immunity-enhancing activity, especially the phagocytic activity of leukocytes. Viable but not heat-killed cells of Weissella kimchii strain PL9001, Lactobacillus fermentum strain PL9005, and L. plantarum strain PL9011 significantly increased the ex vivo phagocytic capacity of mouse peritoneal leukocytes to ingest fluorescein isothiocyanate (FITC)-labeled Escherichia coli in a strain-dependent manner. Results of this and previous studies suggest these LABs as candidates for new probiotics. This is the first report of the enhancement of peritoneal leukocyte activity of these species.

Arabidopsis thaliana defense response to the ochratoxin A-producing strain (Aspergillus ochraceus 3.4412).

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Hao, Junran; Wu, Weihong; Wang, Yan; Yang, Zhuojun; Liu, Yang; Lv, Yangjun; Zhai, Yanan; Yang, Jing; Liang, Zhihong; Huang, Kunlun; Xu, Wentao

2015-05-01

OTA-producing strain Aspergillus ochraceus induced necrotic lesions, ROS accumulation and defense responses in Arabidopsis . Primary metabolic and defense-related proteins changed in proteomics. Ascorbate-glutathione cycle and voltage-dependent anion-selective channel proteins fluctuated. Mycotoxigenic fungi, as widespread contaminants by synthesizing mycotoxins in pre-/post-harvest infected plants and even stored commercial cereals, could usually induce plant-fungi defense responses. Notably, ochratoxin A (OTA) is a nephrotoxic, hepatotoxic, teratogenic, immunotoxic and phytotoxic mycotoxin. Herein, defense responses of model system Arabidopsis thaliana detached leaves to infection of Aspergillus ochraceus 3.4412, an OTA high-producing strain, were studied from physiological, proteomic and transcriptional perspectives. During the first 72 h after inoculation (hai), the newly formed hypersensitive responses-like lesions, decreased chlorophyll content, accumulated reactive oxygen species and upregulated defense genes expressions indicated the defense response was induced in the leaves with the possible earlier motivated jasmonic acid/ethylene signaling pathways and the later salicylic acid-related pathway. Moreover, proteomics using two-dimensional gel electrophoresis 72 hai showed 16 spots with significantly changed abundance and 13 spots corresponding to 12 unique proteins were successfully identified by MALDI-TOF/TOF MS/MS. Of these, six proteins were involved in basic metabolism and four in defense-related processes, which included glutathione-S-transferase F7, voltage-dependent anion-selective channel protein 3 (VDAC-3), osmotin-like protein OSM34 and blue copper-binding protein. Verified from proteomic and/or transcriptional perspectives, it is concluded that the primary metabolic pathways were suppressed with the ascorbate-glutathione cycle fluctuated in response to A. ochraceus and the modulation of VDACs suggested the possibility of structural damage and

Irradiation studies of local Streptomyces strains for higher antibiotic producing capacity. Part of a coordinated programme on radiation microbiology

International Nuclear Information System (INIS)

Kintanar, Q.L.

1978-06-01

The 14 mutants produced by sequential exposure to gamma and ultraviolet irradiation were found to belong to different fundamental types of variants differing in morphology, stability, and metabolite spectra from the parent strain. The first hour mutants, M-1 to M-4 could be considered as belonging to the first category of mutants. Metabolites produced were the same as the parent but differ only in quantity. One was a morphological mutant, M-4 which differed from the parent strain in the production of a brown pigment and conidia, and lack of aerial mycelium. It was found to be most stable and capable of producing high antibiotic yield. The rest of the mutants, M-5 to M-14 could be grouped in the second category. The synthesis of one or more metabolites of the parent strain has been lost by mutation. Unexpectedly, a mutant, M-9 instead of synthesizing either oxytetracycline or tetracycline produced chlortetracycline. Coconut water was found inhibitory to the production of antibiotics by the parent strain and the high and low producing mutants. Modifying the medium by incorporating phosphate and adjusting the initial pH to 4.75 raised the antibiotic yield of the 10% coconut water supplemented medium of M-4 more than the control. Higher pH than the optimum shortened the lag phase but reduced the antibiotic yield while a lower initial pH prevented the growth of the organism giving negligible yield. A reduction of pH to pH 4.5 for the initial 48 hours lengthened the lag phase with almost no adverse effect on the yield. The incorporation of large amounts of coconut water aggravated the amino acid imbalance of the medium

Techno-functional differentiation of two vitamin B12 producing Lactobacillus plantarum strains: an elucidation for diverse future use.

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Bhushan, Bharat; Tomar, S K; Chauhan, Arun

2017-01-01

An appropriate selection of Lactobacillus strain (probiotic/starter/functional) on the basis of its techno-functional characteristics is required before developing a novel fermented functional food. We compared vitamin B 12 (B 12 , cobalamin) producing Lactobacillus plantarum isolates, BHM10 and BCF20, for functional (vitamin over-production, genomic insight to B 12 structural genes, and probiotic attributes) and technological [milks (skim and soy) fermentation and B 12 bio-fortification] characteristics. Addition of B 12 precursors (5-amonolevulinate and dimethylbenzimidazole) to cobalamin-free fermentation medium increased vitamin production in BHM10, BCF20, and DSM20016 (a positive standard) by 3.4-, 4.4-, and 3.86-folds, respectively. Three important B 12 structural genes were detected in L. plantarum species (strains BHM10 and BCF20) by PCR for the first time. The gene sequences were submitted to NCBI GenBank and found phylogenetically closer to respective sequences in B 12 producing Lactobacillus reuteri strains. During comparative probiotic testing, BCF20 showed significantly higher (p < 0.05 to p < 0.001) gastrointestinal tolerance and cell surface hydrophobicity (p < 0.05) than BHM10. Moreover, only BCF20 was found positive for BSH activity and also exhibited comparatively better antagonistic potential against potent pathogens. Conversely, high acid and bile susceptible strain BHM10 displayed significantly higher soy milk fermentation and resultant B 12 bio-fortification abilities during technological testing. Two B 12 quantification techniques, UFLC and competitive immunoassay, confirmed the in vitro and in situ bio-production of bio-available form of B 12 after BHM10 fermentation. Conclusively, techno-functional differentiation of two B 12 producing strains elucidates their diverse future use; BCF20 either for B 12 over-production (in vitro) or as a probiotic candidate, while BHM10 for cobalamin bio-fortification (in situ) in soy milk.

Raw milk traditional Italian ewe cheeses as a source of Lactobacillus casei strains with acid-bile resistance and antigenotoxic properties.

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Corsetti, Aldo; Caldini, Giovanna; Mastrangelo, Mario; Trotta, Francesca; Valmorri, Sara; Cenci, Giovanni

2008-07-31

Twenty-five Lactobacillus casei group strains isolated from ewe cheeses from Abruzzo region, central Italy, were identified by 16S rRNA gene sequencing, differentiated by RAPD-PCR analysis and characterized as in vitro for acid-bile tolerance and antigenotoxic properties. All the strains were very susceptible to simulated gastric fluid (pH 2.0) but most of them recovered viability (ca. 2-3 log-units) when transferred and maintained in simulated intestinal fluid (0.5% w/v bovine bile) for 3 h. Some strains showed potential for deactivating representative genotoxins as highlighted by the SOS-Chromotest. Twelve were active and nine moderately active against 4-nitroquinoline-1-oxide, and one active and only one moderately active against N-methyl-N'-nitro-N-nitrosoguanidine. The active strains produced evident spectroscopic modification of genotoxins after co-incubation. Most isolates with antigenotoxic activity resulted as acid-bile tolerant demonstrating that cheese autochthonous lactobacilli may reach the gut as a viable form and prevent genotoxin DNA damage.

Toxins Produced by Valsa mali var. mali and Their Relationship with Pathogenicity

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Caixia Wang

2014-03-01

Full Text Available Valsa mali var. mali (Vmm, the causal agent of apple tree canker disease, produces various toxic compounds, including protocatechuic acid, p-hydroxybenzoic acid, p-hydroxyacetophenone, 3-(p-hydroxyphenylpropanoic acid and phloroglucinol. Here, we examined the relationship between toxin production and the pathogenicity of Vmm strains and determined their bioactivities in several assays, for further elucidating the pathogenesis mechanisms of Vmm and for developing new procedures to control this disease. The toxins were quantified with the high performance liquid chromatography (HPLC method, and the results showed that the strain with attenuated virulence produced low levels of toxins with only three to four kinds of compounds being detectable. In contrast, higher amounts of toxins were produced by the more aggressive strain, and all five compounds were detected. This indicated a significant correlation between the pathogenicity of Vmm strains and their ability to produce toxins. However, this correlation only existed in planta, but not in vitro. During the infection of Vmm, protocatechuic acid was first detected at three days post inoculation (dpi, and the others at seven or 11 dpi. In addition, all compounds produced noticeable symptoms on host plants at concentrations of 2.5 to 40 mmol/L, with protocatechuic acid being the most effective compound, whereas 3-(p-hydroxyphenylpropanoic acid or p-hydroxybenzoic acid were the most active compounds on non-host plants.

Evaluation of different lactic acid bacterial strains for probiotic characteristics

OpenAIRE

B. Srinu,; T. Madhava Rao,; P. V. Mallikarjuna Reddy; K. Kondal Reddy

2013-01-01

Objective: The objective of the present study was to collect different Lactic acid bacterial strains from culture collection centers and screen their functional probiotic characteristics such as acid tolerance, bile tolerance, antibacterial activity and antibiotic sensitivity for their commercial use. Materials and Methods: Acid and bile tolerence of selected LAB(Lactic acid bacteria) was determined. The antibiotic resistance of Lactobacillus species was assessed using different antibiotic di...

Screening of Non- Saccharomyces cerevisiae Strains for Tolerance to Formic Acid in Bioethanol Fermentation.

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Oshoma, Cyprian E; Greetham, Darren; Louis, Edward J; Smart, Katherine A; Phister, Trevor G; Powell, Chris; Du, Chenyu

2015-01-01

Formic acid is one of the major inhibitory compounds present in hydrolysates derived from lignocellulosic materials, the presence of which can significantly hamper the efficiency of converting available sugars into bioethanol. This study investigated the potential for screening formic acid tolerance in non-Saccharomyces cerevisiae yeast strains, which could be used for the development of advanced generation bioethanol processes. Spot plate and phenotypic microarray methods were used to screen the formic acid tolerance of 7 non-Saccharomyces cerevisiae yeasts. S. kudriavzeii IFO1802 and S. arboricolus 2.3319 displayed a higher formic acid tolerance when compared to other strains in the study. Strain S. arboricolus 2.3319 was selected for further investigation due to its genetic variability among the Saccharomyces species as related to Saccharomyces cerevisiae and availability of two sibling strains: S. arboricolus 2.3317 and 2.3318 in the lab. The tolerance of S. arboricolus strains (2.3317, 2.3318 and 2.3319) to formic acid was further investigated by lab-scale fermentation analysis, and compared with S. cerevisiae NCYC2592. S. arboricolus 2.3319 demonstrated improved formic acid tolerance and a similar bioethanol synthesis capacity to S. cerevisiae NCYC2592, while S. arboricolus 2.3317 and 2.3318 exhibited an overall inferior performance. Metabolite analysis indicated that S. arboricolus strain 2.3319 accumulated comparatively high concentrations of glycerol and glycogen, which may have contributed to its ability to tolerate high levels of formic acid.

Isolation and characterization of new strains of cholesterol-reducing bacteria from baboons.

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Brinkley, A W; Gottesman, A R; Mott, G E

1982-01-01

We isolated and characterized nine new strains of cholesterol-reducing bacteria from feces and intestinal contents of baboons. Cholesterol-brain agar was used for the primary isolation, and subsequent biochemical tests were done in a lecithin-cholesterol broth containing plasmenylethanolamine and various substrates. All strains had similar colony and cell morphology, hydrolyzed the beta-glucosides esculin and amygdalin, metabolized pyruvate, and produced acetate and acetoin. Unlike previously reported strains, the nine new strains did not require cholesterol and an alkenyl ether lipid (e.g., plasmalogen) for growth; however, only two strains reduced cholesterol in the absence of the plasmalogen. These two strains also produced succinate as an end product. Carbohydrate fermentation was variable; some strains produced weak acid (pH 5.5 to 6.0) from only a few carbohydrates, whereas other strains produced strong acid reactions (pH less than or equal to 5.5) from a wide variety of carbohydrates.

Pseudomonas cremoricolorata Strain ND07 Produces N-acyl Homoserine Lactones as Quorum Sensing Molecules

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Nina Yusrina Muhamad Yunos

2014-06-01

Full Text Available Quorum sensing (QS is a bacterial cell-to-cell communication system controlling QS-mediated genes which is synchronized with the population density. The regulation of specific gene activity is dependent on the signaling molecules produced, namely N-acyl homoserine lactones (AHLs. We report here the identification and characterization of AHLs produced by bacterial strain ND07 isolated from a Malaysian fresh water sample. Molecular identification showed that strain ND07 is clustered closely to Pseudomonas cremoricolorata. Spent culture supernatant extract of P. cremoricolorata strain ND07 activated the AHL biosensor Chromobacterium violaceum CV026. Using high resolution triple quadrupole liquid chromatography-mass spectrometry, it was confirmed that P. cremoricolorata strain ND07 produced N-octanoyl-l-homoserine lactone (C8-HSL and N-decanoyl-l-homoserine lactone (C10-HSL. To the best of our knowledge, this is the first documentation on the production of C10-HSL in P. cremoricolorata strain ND07.

Bacteriocin-producing Enterococci from Rabbit Meat

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Szabóová, R.

2012-01-01

Full Text Available Aims: Enterococci are lactic acid bacteria belonging to the division Firmicutes. They occur in different ecosystems, rabbits including. Enterococci can possess probiotic properties and produce antimicrobial substances-bacteriocins. Rabbit meat as nutritionally healthy food offers novel source to study bacteriocin-producing and/or probiotic enterococci. Methodology and results: Enterococci were detected from rabbit meat samples (42. Most of the isolates were allotted to the species Enterococcus faecium by PCR method. The isolates have possessed the structural genes for enterocins A, P, B production. The inhibitory substances produced by the isolated enterococci inhibited the growth of 12 indicators. Of 34 isolates, 15 strains have shown the antimicrobial activity against L. monocytogenes CCM 4699, 12 strains against S. aureus 3A3, 10 strains against S. aureus 5A2 as well as Salmonella enterica serovar Enteritidis PT4. Moreover, enterococci have tolerated 5 % bile, low pH; they have produced lactid acid in the amount from 0.740 ± 0.091 to 1.720 ± 0.095 mmol/l. The isolates were mostly sensitive to antibiotics. Conclusion, significance and impact of study: Bacteriocin-producing strain E. faecium M3a has been selected for more detail characterization of its bacteriocin and probiotic properties with the aim for its further application as an additive.

Screening of wild type Streptomyces isolates able to overproduce clavulanic acid

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Daniela A. Viana Marques

2014-09-01

Full Text Available The selection of new microorganisms able to produce antimicrobial compounds is hoped for to reduce their production costs and the side effects caused by synthetic drugs. Clavulanic acid is a β-lactam antibiotic produced by submerged culture, which is widely used in medicine as a powerful inhibitor of β-lactamases, enzymes produced by bacteria resistant to antibiotics such penicillin and cephalosporin. The purpose of this work was to select the best clavulanic acid producer among strains of Streptomyces belonging to the Microorganism Collection of the Department of Antibiotics of the Federal University of Pernambuco (DAUFPE. Initially, the strains were studied for their capacity to inhibit the action of β-lactamases produced by Klebsiella aerogenes ATCC 15380. From these results, five strains were selected to investigate the batch kinetics of growth and clavulanic acid production in submerged culture carried out in flasks. The results were compared with the ones obtained by Streptomyces clavuligerus ATCC 27064 selected as a control strain. The best clavulanic acid producer was Streptomyces DAUFPE 3060, molecularly identified as Streptomyces variabilis, which increased the clavulanic acid production by 28% compared to the control strain. This work contributes to the enlargement of knowledge on new Streptomyces wild strains able to produce clavulanic acid by submerged culture.

Genome sequence of the thermophilic strain Bacillus coagulans 2-6, an efficient producer of high-optical-purity L-lactic acid.

Science.gov (United States)

Su, Fei; Yu, Bo; Sun, Jibin; Ou, Hong-Yu; Zhao, Bo; Wang, Limin; Qin, Jiayang; Tang, Hongzhi; Tao, Fei; Jarek, Michael; Scharfe, Maren; Ma, Cuiqing; Ma, Yanhe; Xu, Ping

2011-09-01

Bacillus coagulans 2-6 is an efficient producer of lactic acid. The genome of B. coagulans 2-6 has the smallest genome among the members of the genus Bacillus known to date. The frameshift mutation at the start of the d-lactate dehydrogenase sequence might be responsible for the production of high-optical-purity l-lactic acid.

Nematicidal Activity of Kojic Acid Produced by Aspergillus oryzae against Meloidogyne incognita.

Science.gov (United States)

Kim, Tae Yoon; Jang, Ja Yeong; Jeon, Sun Jeong; Lee, Hye Won; Bae, Chang-Hwan; Yeo, Joo Hong; Lee, Hyang Burm; Kim, In Seon; Park, Hae Woong; Kim, Jin-Cheol

2016-08-28

The fungal strain EML-DML3PNa1 isolated from leaf of white dogwood (Cornus alba L.) showed strong nematicidal activity with juvenile mortality of 87.6% at a concentration of 20% fermentation broth filtrate at 3 days after treatment. The active fungal strain was identified as Aspergillus oryzae, which belongs to section Flavi, based on the morphological characteristics and sequence analysis of the ITS rDNA, calmodulin (CaM), and β-tubulin (BenA) genes. The strain reduced the pH value to 5.62 after 7 days of incubation. Organic acid analysis revealed the presence of citric acid (515.0 mg/kg), malic acid (506.6 mg/kg), and fumaric acid (21.7 mg/kg). The three organic acids showed moderate nematicidal activities, but the mixture of citric acid, malic acid, and fumaric acid did not exhibit the full nematicidal activity of the culture filtrate of EML- DML3PNa1. Bioassay-guided fractionation coupled with (1)H- and (13)C-NMR and EI-MS analyses led to identification of kojic acid as the major nematicidal metabolite. Kojic acid exhibited dose-dependent mortality and inhibited the hatchability of M. incognita, showing EC50 values of 195.2 µg/ml and 238.3 µg/ml, respectively, at 72 h postexposure. These results suggest that A. oryzae EML-DML3PNa1 and kojic acid have potential as a biological control agent against M. incognita.

Benefits of combinative application of probiotic, enterocin M-producing strain Enterococcus faecium AL41 and Eleutherococcus senticosus in rabbits.

Science.gov (United States)

Lauková, Andrea; Simonová, Monika Pogány; Chrastinová, Ľubica; Plachá, Iveta; Čobanová, Klaudia; Formelová, Zuzana; Chrenková, Mária; Ondruška, Ľubomír; Strompfová, Viola

2016-03-01

This study presents the effects of the probiotic and enterocin M-producing strain Enterococcus faecium AL41 on microbiota, phagocytic activity (PA), oxidative stress, performance and biochemical parameters when applied individually or in combination with Eleutherococcus senticosus in rabbits. The novelty of the study lies in the use of our non-rabbit-derived strain (AL41 = CCM8558) which produces new enterocin M. Ninety-six post-weaned rabbits (Hyplus breed) aged 5 weeks were divided into three experimental groups, 24 in each: E. senticosus (ES, 30 g/100 kg) in feed, E. faecium AL41 (10(9) CFU/mL marked by rifampicin to differentiate it from other enterococci) in water, and ES + AL. AL41 colonized sufficiently in rabbits to reduce coliforms, staphylococci, pseudomonads and clostridia. Slight decrease in bacteria was also found in the caecum and appendix. Phagocytic activity was significantly increased in the experimental groups compared to the control group (CG) (p < 0.001; p < 0.05). Applications did not evoke oxidative stress. Biochemical parameters in blood and caecal organic acids were slightly influenced. Average daily weight gain was slightly higher in ES and AL + ES. Combinative application of E. faecium with E. senticosus can be beneficial in rabbits. AL41 strain alone and in combination with ES produced reduction in spoilage bacteria; the highest stimulation of PA was in the AL41 + ES group.

[Genetic modification of Methylobacterium extorquens G10 producer strain of polyhydroxybutyrate].

Science.gov (United States)

Fedorov, D N; Zamakhaeva, S A; Ezhov, V A; Doronina, N V; Trotsenko, Iu A

2014-01-01

The effect of the increased copy number of polyhydroxybutyrate (PHB) biosynthesis genes in pink-pigmented methylobacterium Methylobacterium extorquens G10 on properties of the biopolymer was studied. The activity of poly-3-hydroxybutyril-synthase (PHB-synthase) was shown to increase and the molecular weight of synthesized PHB decreases twofold (150 --> 79 kDa) after insertion of extra copies of phaC and phaCAB genes into cells of the producer strain, whereas the physicochemical properties of the plastic changed insignificantly. White mutant M. extorquens G10-W with disrupted synthesis of the carotenoid pigment (defect by the crtI gene, which codes for phytoene desaturase) was established to have the same rate of growth and level of PHB accumulation as the initial strain G10. The G10-W strain is a promising producer of PHB, with decreased expenses for purification and PHB biosynthesis.

Exopolysaccharides produced by lactic acid bacteria

NARCIS (Netherlands)

Caggianiello, Graziano; Kleerebezem, Michiel; Spano, Giuseppe

2016-01-01

A wide range of lactic acid bacteria (LAB) is able to produce capsular or extracellular polysaccharides, with various chemical compositions and properties. Polysaccharides produced by LAB alter the rheological properties of the matrix in which they are dispersed, leading to typically viscous and

Characterization of a bacteriocin-like substance produced from a novel isolated strain of Bacillus subtilis SLYY-3

Science.gov (United States)

Li, Junfeng; Li, Hongfang; Zhang, Yuanyuan; Duan, Xiaohui; Liu, Jie

2014-12-01

In the present research, the strain SLYY-3 was isolated from sediments of Jiaozhou Bay, Qingdao, China. The strain SLYY-3, which produced a bacteriocin-like substance (BLS), was characterized to be a strain of Bacillus subtillis by biochemical profiling and 16S rDNA sequence analysis. It is the first time to report that Bacillus subtilis from Jiaozhou Bay sediments could produce a BLS. The BLS of B. subtillis SLYY-3 exhibited strong inhibitory activity against gram-positive bacteria (including Staphylococcus aureus and B. subtillis) and some fungi (including Penicillium glaucum, Aspergillus niger and Aspergillus flavus). The antimicrobial activity was detected from culture in the exponential growth phase and reached its maximum when culture entered into stationary growth phase. It was thermo-tolerant even when being kept at 100°C for 60 min without losing any activity and stable over a wide pH range from 1.0 to 12.0 while being inactivated by proteolytic enzyme and trypsin, indicating the proteinaceous nature of the BLS. The BLS was purified by precipitation with hydrochloric acid (HCl) and gel filteration (Sephadex G-100). SDS-PAGE analysis of the extracellular peptides of SLYY-3 revealed a bacteriocin-like protein with a molecular mass of 66 kDa. Altogether, these characteristics indicate the potential of the BLS for food industry as a protection against pathogenic and spoilage microorganisms.

Production of itaconic acid from acetate by engineering acid-tolerant Escherichia coli W.

Science.gov (United States)

Noh, Myung Hyun; Lim, Hyun Gyu; Woo, Sung Hwa; Song, Jinyi; Jung, Gyoo Yeol

2018-03-01

Utilization of abundant and cheap carbon sources can effectively reduce the production cost and enhance the economic feasibility. Acetate is a promising carbon source to achieve cost-effective microbial processes. In this study, we engineered an Escherichia coli strain to produce itaconic acid from acetate. As acetate is known to inhibit cell growth, we initially screened for a strain with a high tolerance to 10 g/L of acetate in the medium, and the W strain was selected as the host. Subsequently, the WC strain was obtained by overexpression of cad (encoding cis-aconitate decarboxylase) using a synthetic promoter and 5' UTR. However, the WC strain produced only 0.13 g/L itaconic acid because of low acetate uptake. To improve the production, the acetate assimilating pathway and glyoxylate shunt pathway were amplified by overexpression of pathway genes as well as its deregulation. The resulting strain, WCIAG4 produced 3.57 g/L itaconic acid (16.1% of theoretical maximum yield) after 88 hr of fermentation with rapid acetate assimilation. These efforts support that acetate can be a potential feedstock for biochemical production with engineered E. coli. © 2017 Wiley Periodicals, Inc.

A rapid NMR-based method for discrimination of strain-specific cell wall teichoic acid structures reveals a third backbone type in Lactobacillus plantarum.

Science.gov (United States)

Tomita, Satoru; Tanaka, Naoto; Okada, Sanae

2017-03-01

The lactic acid bacterium Lactobacillus plantarum is capable of producing strain-specific structures of cell wall teichoic acid (WTA), an anionic polysaccharide found in the Gram-positive bacterial cell wall. In this study, we established a rapid, NMR-based procedure to discriminate WTA structures in this species, and applied it to 94 strains of L. plantarum. Six previously reported glycerol- and ribitol-containing WTA subtypes were successfully identified from 78 strains, suggesting that these were the dominant structures. However, the level of structural variety differed markedly among bacterial sources, possibly reflecting differences in strain-level microbial diversity. WTAs from eight strains were not identified based on NMR spectra and were classified into three groups. Structural analysis of a partial degradation product of an unidentified WTA produced by strain TUA 1496L revealed that the WTA was 1-O-β-d-glucosylglycerol. Two-dimensional NMR analysis of the polymer structure showed phosphodiester bonds between C-3 and C-6 of the glycerol and glucose residues, suggesting a polymer structure of 3,6΄-linked poly(1-O-β-d-glucosyl-sn-glycerol phosphate). This is the third WTA backbone structure in L. plantarum, following 3,6΄-linked poly(1-O-α-d-glucosyl-sn-glycerol phosphate) and 1,5-linked poly(ribitol phosphate). © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Fumonisin and Ochratoxin Production in Industrial Aspergillus niger Strains

Science.gov (United States)

Frisvad, Jens C.; Larsen, Thomas O.; Thrane, Ulf; Meijer, Martin; Varga, Janos; Samson, Robert A.; Nielsen, Kristian F.

2011-01-01

Aspergillus niger is perhaps the most important fungus used in biotechnology, and is also one of the most commonly encountered fungi contaminating foods and feedstuffs, and occurring in soil and indoor environments. Many of its industrial applications have been given GRAS status (generally regarded as safe). However, A. niger has the potential to produce two groups of potentially carcinogenic mycotoxins: fumonisins and ochratoxins. In this study all available industrial and many non-industrial strains of A. niger (180 strains) as well as 228 strains from 17 related black Aspergillus species were examined for mycotoxin production. None of the related 17 species of black Aspergilli produced fumonisins. Fumonisins (B2, B4, and B6) were detected in 81% of A. niger, and ochratoxin A in 17%, while 10% of the strains produced both mycotoxins. Among the industrial strains the same ratios were 83%, 33% and 26% respectively. Some of the most frequently used strains in industry NRRL 337, 3112 and 3122 produced both toxins and several strains used for citric acid production were among the best producers of fumonisins in pure agar culture. Most strains used for other biotechnological processes also produced fumonisins. Strains optimized through random mutagenesis usually maintained their mycotoxin production capability. Toxigenic strains were also able to produce the toxins on media suggested for citric acid production with most of the toxins found in the biomass, thereby questioning the use of the remaining biomass as animal feed. In conclusion it is recommended to use strains of A. niger with inactive or inactivated gene clusters for fumonisins and ochratoxins, or to choose isolates for biotechnological uses in related non-toxigenic species such as A. tubingensis, A. brasiliensis, A vadensis or A. acidus, which neither produce fumonisins nor ochratoxins. PMID:21853139

Aflatoxin B1 producing potential of Aspergillus flavus strains isolated ...

African Journals Online (AJOL)

STORAGESEVER

2009-07-20

Jul 20, 2009 ... consumption of aflatoxin contaminated food and feed. (Reddy and ..... intervals by artificial inoculation of A. parasiticus on rice grains. ... additive for culture media for rapid identification of aflatoxin producing. Aspergillus strains ...

Antibacterial activity and optimisation of bacteriocin producing lactic acid bacteria isolated from beef (red meat) samples

International Nuclear Information System (INIS)

Ali, N.M.; Mazhar, B.; Khadija, I.; Kalim, B.

2016-01-01

Bacteriocin producing bacteria are commonly found in meat products to enhance their shelf-life. In the present study, bacterial species were isolated from meat samples (beef) from different localities of Lahore, Pakistan. MRS agar medium was used to isolate lactic acid bacteria (LAB) through spread and streak methods (incubated for 72 h at 37 degree C). Identification of bacteriocinogenic LAB strains was done by using staining techniques, morphology based characteristics and biochemical tests. These strains were BSH 1b, BSH 3a, BIP 4a, BIP 3a, BIP 1b and BRR 3a. Antibacterial activity of LAB was performed against food borne pathogens viz., Escherichia coli and Staphylococcus aureus through paper disc diffusion method. Three bacterial strains showed maximum inhibition and characterised by ribotyping viz., BIP 4a was identified as Lactobacillus curvatures, BIP 3a was Staphylococcus warneri and BIP 1b was Lactobacillus graminis . Optimum pH 5-6.5 and 30-37 degree C temperature for isolated bacterial strains was recorded. Protein concentration measured was 0.07 mg/mL for BSH 1b, 0.065 mg/mL for BSH 3a, 0.057 mg/mL for BIP 4a, 0.062 mg/mL for BIP 1b, 0.065 mg/mL for BIP 3a and for BRR 3a 0.078 mg/mL, respectively. Bacteriocin of all isolates except BIP 3a was found to be sensitive towards pepsin and resistant towards Rnase. Bacteriocin production was stable at between pH 5.0 and 6.0 and resistant temperature was 40 degree C. It was concluded that lactic acid bacteria (LAB) from meat can be helpful as antibacterial agents against food-borne bacterial pathogens because of thermostable producing bacteriocin. (author)

Prevalence and clonal relationship of ESBL-producing Salmonella strains from humans and poultry in northeastern Algeria.

Science.gov (United States)

Djeffal, Samia; Bakour, Sofiane; Mamache, Bakir; Elgroud, Rachid; Agabou, Amir; Chabou, Selma; Hireche, Sana; Bouaziz, Omar; Rahal, Kheira; Rolain, Jean-Marc

2017-05-15

The aims of this study were to investigate Salmonella contamination in broiler chicken farms and slaughterhouses, to assess the antibiotic resistance profile in avian and human Salmonella isolates, and to evaluate the relationship between avian and human Extended Spectrum β-Lactamase (ESBL)-producing isolates. Salmonella was screened in different sample matrices collected at thirty-two chicken farms and five slaughterhouses. The human isolates were recovered from clinical specimens at the University Teaching Hospital of Constantine (UTH). All suspected colonies were confirmed by MALDI-TOF (Matrix Assisted Laser Desorption Ionization Time OF light) and serotyped. Susceptibility testing against 13 antibiotics including, amoxicillin/clavulanic acid, ticarcillin, cefoxitin, cefotaxime, aztreonam, imipenem, ertapenem, gentamicin, amikacin, ciprofloxacin, colistin, trimethoprim/sulfamethoxazole and fosfomycin, was performed using the disk diffusion method on Mueller-Hinton agar. ESBL-production was screened by the double-disk synergy test and confirmed by molecular characterization using PCR (polymerase chain reaction) amplification and sequencing of ESBL encoding genes. Clonality of the avian and human strains was performed using the Multi Locus Sequencing Typing method (MLST). Forty-five isolated avian Salmonella strains and 37 human collected ones were studied. Five S. enterica serotypes were found in avian isolates (mainly Kentucky) and 9 from human ones (essentially Infantis). 51.11% and 26.6% of the avian isolates were resistant to ciprofloxacin and cefotaxime, respectively, whereas human isolates were less resistant to these antibiotics (13.5% to ciprofloxacin and 16.2% to cefotaxime). Eighteen (12 avian and 6 human) strains were found to produce ESBLs, which were identified as bla CTX-M-1 (n = 12), bla CTX-M-15 (n = 5) and bla TEM group (n = 8). Interestingly, seven of the ESBL-producing strains (5 avian and 2 human) were of the same ST (ST15) and

The effect of Aspergillus niger mutagenization on citric acid biosynthesis

Directory of Open Access Journals (Sweden)

Stanisław Walisch

2014-08-01

Full Text Available The industrial A. niger strain producing citric acid was mutagenized with the use of new chemical mutagens: free nitroxyl radicals. Strains of higher citric acid production yield were obtained. Citric acid was produced in a shorter time compared to the initial strain. During 6-12 months of storage most of the strains preserved their positive features which proves that mutants with profitable biotechnological properties were obtained. These mutants are used in industrial process.

Noble strain of Sparassis latifolia produces high content of β-glucan

Directory of Open Access Journals (Sweden)

Dong Ju Lee

2015-08-01

Conclusions: These results indicate that the nucleotide sequences and the amino acid sequences of RPB2 can be used to identify individual Sparassis sp. The Sparassis strain CLM1 may be best for developing a remedy to prevent or treat cancer and other chronic diseases.

Fumonisin and Ochratoxin Production in Industrial Aspergillus niger Strains

DEFF Research Database (Denmark)

Frisvad, Jens Christian; Larsen, Thomas Ostenfeld; Thrane, Ulf

2011-01-01

as safe). However, A. niger has the potential to produce two groups of potentially carcinogenic mycotoxins: fumonisins and ochratoxins. In this study all available industrial and many non-industrial strains of A. niger (180 strains) as well as 228 strains from 17 related black Aspergillus species were...... examined for mycotoxin production. None of the related 17 species of black Aspergilli produced fumonisins. Fumonisins (B(2), B(4), and B(6)) were detected in 81% of A. niger, and ochratoxin A in 17%, while 10% of the strains produced both mycotoxins. Among the industrial strains the same ratios were 83......%, 33% and 26% respectively. Some of the most frequently used strains in industry NRRL 337, 3112 and 3122 produced both toxins and several strains used for citric acid production were among the best producers of fumonisins in pure agar culture. Most strains used for other biotechnological processes also...

Key Process Conditions for Production of C4 Dicarboxylic Acids in Bioreactor Batch Cultures of an Engineered Saccharomyces cerevisiae Strain

NARCIS (Netherlands)

Zelle, R.M.; De Hulster, E.; Kloezen, W.; Pronk, J.T.; Van Maris, A.J.A.

2010-01-01

A recent effort to improve malic acid production by Saccharomyces cerevisiae by means of metabolic engineering resulted in a strain that produced up to 59 g liter(-1) of malate at a yield of 0.42 mol (mol glucose)(-1) in calcium carbonate-buffered shake flask cultures. With shake flasks, process

[GM1-dot-EIA for the detection of toxin-producing Vibrio cholerae strains].

Science.gov (United States)

Markina, O V; Alekseeva, L P; Telesmanich, N R; Chemisova, O S; Akulova, M V; Markin, N V

2011-05-01

A new variant of enzyme immunoassay (EIA) has been developed on the basis of GM1 gangliosides to detect the toxin-producing Vibrio cholerae strains--GM1-dot-EIA. Experiments were run using a nitrocellulose membrane to bind GM1 gangliosides and polyclonal antitoxic serum to detect cholerogen. GM1-dot-EIA testing identified cholera toxin in 11 of 13 supernatants of V. cholerae eltor ctx(+) strains isolated from man and in 3 of 7 supernatants of V. cholerae eltor ctx(+) strains isolated from water. These data agree with those obtained in CM1-EIA. There was no reaction with the supernatants of other microorganisms. The sensitivity of the technique was 10 ng/ml. Thus, the simple and specific GM1-dot-EIA may be recommended to detect toxin-producing V cholerae strains isolated from man and water.

Genome-scale model-driven strain design for dicarboxylic acid production in Yarrowia lipolytica.

Science.gov (United States)

Mishra, Pranjul; Lee, Na-Rae; Lakshmanan, Meiyappan; Kim, Minsuk; Kim, Byung-Gee; Lee, Dong-Yup

2018-03-19

Recently, there have been several attempts to produce long-chain dicarboxylic acids (DCAs) in various microbial hosts. Of these, Yarrowia lipolytica has great potential due to its oleaginous characteristics and unique ability to utilize hydrophobic substrates. However, Y. lipolytica should be further engineered to make it more competitive: the current approaches are mostly intuitive and cumbersome, thus limiting its industrial application. In this study, we proposed model-guided metabolic engineering strategies for enhanced production of DCAs in Y. lipolytica. At the outset, we reconstructed genome-scale metabolic model (GSMM) of Y. lipolytica (iYLI647) by substantially expanding the previous models. Subsequently, the model was validated using three sets of published culture experiment data. It was finally exploited to identify genetic engineering targets for overexpression, knockout, and cofactor modification by applying several in silico strain design methods, which potentially give rise to high yield production of the industrially relevant long-chain DCAs, e.g., dodecanedioic acid (DDDA). The resultant targets include (1) malate dehydrogenase and malic enzyme genes and (2) glutamate dehydrogenase gene, in silico overexpression of which generated additional NADPH required for fatty acid synthesis, leading to the increased DDDA fluxes by 48% and 22% higher, respectively, compared to wild-type. We further investigated the effect of supplying branched-chain amino acids on the acetyl-CoA turn-over rate which is key metabolite for fatty acid synthesis, suggesting their significance for production of DDDA in Y. lipolytica. In silico model-based strain design strategies allowed us to identify several metabolic engineering targets for overproducing DCAs in lipid accumulating yeast, Y. lipolytica. Thus, the current study can provide a methodological framework that is applicable to other oleaginous yeasts for value-added biochemical production.

Aspergillus oryzae-based cell factory for direct kojic acid production from cellulose.

Science.gov (United States)

Yamada, Ryosuke; Yoshie, Toshihide; Wakai, Satoshi; Asai-Nakashima, Nanami; Okazaki, Fumiyoshi; Ogino, Chiaki; Hisada, Hiromoto; Tsutsumi, Hiroko; Hata, Yoji; Kondo, Akihiko

2014-05-18

Kojic acid (5-Hydroxy-2-(hydroxymethyl)-4-pyrone) is one of the major secondary metabolites in Aspergillus oryzae. It is widely used in food, pharmaceuticals, and cosmetics. The production cost, however, is too high for its use in many applications. Thus, an efficient and cost-effective kojic acid production process would be valuable. However, little is known about the complete set of genes for kojic acid production. Currently, kojic acid is produced from glucose. The efficient production of kojic acid using cellulose as an inexpensive substrate would help establish cost-effective kojic acid production. A kojic acid transcription factor gene over-expressing the A. oryzae strain was constructed. Three genes related to kojic acid production in this strain were transcribed in higher amounts than those found in the wild-type strain. This strain produced 26.4 g/L kojic acid from 80 g/L glucose. Furthermore, this strain was transformed with plasmid harboring 3 cellulase genes. The resultant A. oryzae strain successfully produced 0.18 g/L of kojic acid in 6 days of fermentation from the phosphoric acid swollen cellulose. Kojic acid was produced directly from cellulose material using genetically engineered A. oryzae. Because A. oryzae has efficient protein secretion ability and secondary metabolite productivity, an A. oryzae-based cell factory could be a platform for the production of various kinds of bio-based chemicals.

CHARACTERIZATION OF EXTENDED-SPECTRUM Β-LACTAMASE-PRODUCING ESCHERICHIA COLI STRAINS ISOLATED FROM DAIRY PRODUCTS

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Rahem Khoshbakht

2014-02-01

Full Text Available Extended-spectrum β-lactamases (ESBLs are enzymes that hydrolyze the β-lactam ring, and ESBL-producing E. coli has rapidly spread worldwide with pose a serious hazard for humans. The aim of this study was to determine the prevalence of ESBL producing E. coli and molecular evaluation of four ESBL-associated genes among E. coli strains isolated from milk and cheese in southern Iran. Antibiotic susceptibility test was carried out for a total of 150 isolates of E. coli, previously collected from dairy products. ESBL production was screened using a double-disc synergy test (DDST and presence of four ESBL genes (PER, VEB, TEM and CTX-M was tested using PCR. Among 150 E. coli strains 57 (38% isolates were identified as ESBL-producing strains. All ESBL positive isolates could be typed for one or more genes and the most prevalent ESBL-associated gene was CTX-M (80.7%. The PER gene was not present among isolates. Isolates showed high susceptibility to imipe¬nem and cefoxitin. The results showed the high prevalence of ESBL producing E. coli strains among dairy products and high occurrence of CTX-M-associated ESBL activity among isolates indicating the hazards of increasing the strains with antibiotic resistance which can transfer to human trough the dairy food products.

Inactivation of exopolysaccharide and 3-hydroxypropionaldehyde-producing lactic acid bacteria in apple juice and apple cider by enterocin AS-48.

Science.gov (United States)

Martínez-Viedma, Pilar; Abriouel, Hikmate; Omar, Nabil Ben; Valdivia, Eva; López, Rosario Lucas; Gálvez, Antonio

2008-03-01

The bacteriocin enterocin AS-48 was tested against exopolysaccharide producing lactic acid bacteria (LAB) strains of Lactobacillus collinoides, Lactobacillus dioliovorans and Pediococcus parvulus as well as two 3-hydroxypropionaldehyde (3-HPA)-producing Lb. collinoides strains causing apple cider spoilage. In fresh-made apple juice, a bacteriocin concentration of 2.5 microg/ml reduced the LAB viable cell counts below detection levels during the course of incubation at 10 and 22 degrees C for most strains tested, except for Lb. collinoides 5 and Lb. dioliovorans 29. These two strains were significantly inhibited at 10 degrees C by 5 microg/ml AS-48 or completely inactivated at 22 degrees C. In a commercial Basque apple cider, the added bacteriocin (2.5 microg/ml for Lb. collinoides strains 9 and 10, and 5 microg/ml for the rest of strains) completely inactivated all LAB strains tested during storage at 10 as well as 22 degrees C. In the commercial Asturian apple cider tested the LAB strains showed a poor capacity for survival, but the added bacteriocin was equally effective in reducing the numbers of survivors. When a cocktail of the five LAB strains was tested in commercial Basque apple cider, viable cell counts were reduced below detection levels after 2 days for a bacteriocin concentration of 12.5 microg/ml regardless of storage temperature. Comparison of RAPD-PCR profiles revealed that strain Lb. dioliovorans 29 was always the predominant survivor detected in bacteriocin-treated samples.

Characterization of new exopolysaccharides produced by coculturing of L. kefiranofaciens with yoghurt strains.

Science.gov (United States)

Ahmed, Zaheer; Wang, Yanping; Anjum, Nomana; Ahmad, Hajra; Ahmad, Asif; Raza, Mohsin

2013-08-01

This project was designed to study the coculturing affect of exopolysaccharide (EPS) producing strains Lactobacillus kefiranofaciens (L.k) ZW3, with non EPS producing strains L. bulgaricus (L.b) and Streptococcus thermophilus (S.t) in three different combinations: L.k+L.b, L.k+S.t, and L.k+L.b+S.t. FTIR analysis revealed presence of strong stretch in regions of 3400, 2900 and 1647cm(-1) which is characteristic of a typical polysaccharide. Co-cultured EPSs were composed of glucose, galactose, arabinose and xylose; and their sugar compositions were different from ZW3 polysaccharide that was mainly composed of gluco-galactan. Peak temperature for L.k+L.b, L.k+S.t, L.k+S.t+L.b and ZW3 polymers were 90.59, 87.61, 95.18 and 97.38°C, respectively. Thermal analysis revealed degradation temperature of 326.44, 294.6, 296.7 and 299.62°C for L.k+L.b, L.k+S.t, L.k+S.t+L.b and ZW3 polymers, respectively. SEM and AFM analysis divulged that three cocultured EPSs had different surface morphology than ZW3 polymer. Since co-cultured polymers have different structure than the polymer produced exclusively by EPS producing strain, it can be safely concluded from the study that co-culturing can be one way to change the structure of polymers. Coculturing of L. kefiranofaciens with non-EPS producing strains resulted in yoghurt with increased viscosity and delayed syneresis. Copyright © 2013 Elsevier B.V. All rights reserved.

Safety Evaluation of Enterocin Producer Enterococcus sp. Strains Isolated from Traditional Turkish Cheeses.

Science.gov (United States)

Avcı, Mine; Özden Tuncer, Banu

2017-07-06

The purpose of this study was to determine the antimicrobial activity and occurrence of bacteriocin structural genes in Enterococcus spp. isolated from different cheeses and also investigate some of their virulence factors. Enterococcus strains were isolated from 33 different cheeses. Enterococcus faecium (6 strains) and Enterococcus faecalis (5 strains) enterocin-producing strains were identified by 16S rDNA analyses. Structural genes entA, entB, entP and entX were detected in some isolates. Multiple enterocin structural genes were found in 7 strains. None of the tested enterococci demonstrated anyβ-haemolytic activity and only one strain had gelatinase activity. Six strains showed multiple antibiotic resistance patterns and in addition, vanA and several virulence genes were detected in many strains. Only E. faecalis MBE1-9 showed tyrosine decarboxylase activity and tdc gene was detected only in this strain.

Chemical Profile of Monascus ruber Strains

Directory of Open Access Journals (Sweden)

Ahamed M. Moharram

2012-01-01

Full Text Available Chemical profile of Monascus ruber strains has been studied using gas chromatography-mass spectrometry (GC/MS analysis. The colour intensity of the red pigment and secondary metabolic products of two M. ruber strains (AUMC 4066 and AUMC 5705 cultivated on ten different media were also studied. Metabolic products can be classified into four categories: anticholesterol, anticancer, food colouring, and essential fatty acids necessary for human health. Using GC/MS, the following 88 metabolic products were detected: butyric acid and its derivatives (25 products, other fatty acids and their derivatives (19 products, pyran and its derivatives (22 products and other metabolites (22 products. Among these, 32 metabolites were specific for AUMC 4066 strain and 34 for AUMC 5705 strain, whereas 22 metabolites were produced by both strains on different tested substrates. Production of some metabolites depended on the substrate used. High number of metabolites was recorded in the red pigment extract obtained by both strains grown on malt broth and malt agar. Also, 42 aroma compounds were recorded (4 alcohols, 2 benzaldehydes, 27 esters, 3 lactones, 1 phenol, 1 terpenoid, 3 thiol compounds and acetate-3-mercapto butyric acid. Thin layer chromatography and GC/MS analyses revealed no mycotoxin citrinin in any media used for the growth of the two M. ruber strains.

Draft Genome Sequence of Hoeflea sp. Strain BAL378, a Potential Producer of Bioactive Compounds

DEFF Research Database (Denmark)

Bentzon-Tilia, Mikkel; Riemann, Lasse; Gram, Lone

2014-01-01

Some phytoplankton-associated marine bacteria produce bioactive compounds. Members of the genus Hoeflea may be examples of such bacteria; however, data describing their metabolisms are scarce. Here, we report the draft genome sequence of Hoeflea sp. strain BAL378, a putative producer of bacterioc......Some phytoplankton-associated marine bacteria produce bioactive compounds. Members of the genus Hoeflea may be examples of such bacteria; however, data describing their metabolisms are scarce. Here, we report the draft genome sequence of Hoeflea sp. strain BAL378, a putative producer...

Strain diversity of CTX-M-producing Enterobacteriaceae in individual pigs

DEFF Research Database (Denmark)

Hansen, Katrine Hartung; Bortolaia, Valeria; Damborg, Peter Panduro

2014-01-01

of CTX-M-2/97-producing Proteus mirabilis or Providencia rettgeri was observed in two sows and two offspring. At least two genetically unrelated CTX-M-producing E. coli strains were isolated from approximately one fourth of the samples with remarkable differences between isolates obtained by enrichment...

Screening on the high yield validamycin producing strain by implantation with N+ and Ti+ ion source

International Nuclear Information System (INIS)

Yu Long; An Xiao

2007-01-01

In order to compared the mutagenic effects of the validamycin producing the strain (Streptomyces hygroscopicus var. Jingganggensis Yen.) was implanted with two kinds of ion sources. The results showed that when two kinds of ion sources implanted into the strain by turns, more positive mutants and higher yield would be acquired. Using this method, a high-yielding strain B1-3 was obtained, which produce the titer of validamycin A of 21514, and was 54.4% higher than that of the original strain. (authors)

Screening for Glucosyltransferase gene (gtf from exopolysaccahride producing lactic acid bacteria

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Donna M. Ariestanti

2008-04-01

Full Text Available Glucosyltransferase (GTF is an enzyme involved in exopolysaccharide (EPS polymer synthesis in microbes. One example of EPS that has been used in pharmaceutical and medical application is dextran. Dextran has been used in conjugated-drug delivery system as matrix. As a group of microbes producing EPS, lactic acid bacteria (LAB have been well reported carrying sucrase genes glucosyltransferase (gtf, as well as fructosyltransferases (ftf. In an attempt to search for novel gtf genes as the aim of this study, LAB collection isolated from local sources yielded from previous study were screened performing PCR using degenerate primers DegFor and DegRev. An approximately 660 base pairs (bp amplicons were obtained by using genomic DNAs of those LAB isolates as templates with conserved region of gtf genes catalytic domain as target. Two out of 20 LAB strains were yielded no amplicon as observed on agarose gel, while one strain exhibited non-specific amplicon DNA bands with sizes other than 660 bp. The two negative ones were isolated from soil obtained from dairy product waste field and from waste of soy sauce from previous study, while the latter was isolated from waste of soy sauce.

Acid resistance and response to pH-induced stress in two Lactobacillus plantarum strains with probiotic potential.

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Šeme, H; Gjuračić, K; Kos, B; Fujs, Š; Štempelj, M; Petković, H; Šušković, J; Bogovič Matijašić, B; Kosec, G

2015-01-01

Two new Lactobacillus plantarum strains, KR6-DSM 28780 and M5 isolated from sour turnip and traditional dried fresh cheese, respectively, were evaluated for species identity, antibiotic susceptibility, resistance to gastrointestinal conditions and adaptive response to low pH. Resistance mechanisms involved in the adaptation to acid-induced stress in these two strains were investigated by quantitative PCR of the atpA, cfa1, mleS and hisD genes. In addition to absence of antibiotic resistance, the two L. plantarum strains showed excellent survival rates at pH values as low as 2.4. Adaptive response to low pH was clearly observed in both strains; strain KR6 was superior to M5, as demonstrated by its ability to survive during 3 h incubation at pH 2.0 upon adaptation to moderately acidic conditions. In contrast, acid adaptation did not significantly affect the survival rate during simulated passage through the gastrointestinal tract. In both strains, induction of histidine biosynthesis (hisD) was upregulated during the acid adaptation response. In addition, significant upregulation of the cfa1 gene, involved in modulation of membrane fatty acid composition, was observed during the adaptation phase in strain KR6 but not in strain M5. Cells adapted to moderately acidic conditions also showed a significantly increased viability after the lyophilisation procedure, a cross-protection phenomenon providing additional advantage in probiotic application.

NEW STRAIN PRODUCERS OF BIOBUTANOL. III. METHODS OF INCREASED BUTANOL ACCUMULATION FROM BIOMASS OF SWITCHGRASS Panicum virgatum L.

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Tigunova O. O.

2015-08-01

Full Text Available The aim of this work was to enlarge accumulation of butanol from switchgrass Panicum virgatum L. biomass using strains-producers obtained from grounds and silts of Kyiv lakes. The objects of the study were strains of C. acetobutylicum ІМВ B-7407 (IFBG C6H, Clostridium acetobutylicum IFBG C6H 5М and Clostridium tyrobutyricum IFBG C4B from the "Collections of microbial strains and lines of plants for food and agricultural biotechnology" of the Public Institution "Institute of Food Biotechnology and Genomics" of the National Academy of Sciences of Ukraine. Gas chromatography was used to determine the alcohol concentration at the stage of solvent synthesis. To determine the effect of butanol precursors during cultivation, butyric, lactic and acetic acids were used. Optimization of processing parameters, which was based on the needs of cultures, allowed us to increase the yield by 20 and 50% for the initial and mutant strain respectively. Using synthetic precursors (such as lactic, butyric and acetic acid during cultivation increased total concentration of butanol by 1.7 times. To optimize the process, a study was carried out using acetone- butyl grains. Using of acetone-butyl grains in concentrations up to 60% does not affect the synthesis of butanol by C. acetobutylicum IFBG C6H 5M. Increasing the concentration of grains led to decrease in accumulation of butanol. Almost double increase in accumulation of the target product (butanol was achieved using two-stage fermentation and/or precursors of synthesis. It was shown the possibility of using acetone-butyl grains in fermentation. As a result the mass fraction of the waste was reduced.

Analysis of Growth Inhibition and Metabolism of Hydroxycinnamic Acids by Brewing and Spoilage Strains of Brettanomyces Yeast.

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Lentz, Michael; Harris, Chad

2015-10-15

Brettanomyces yeasts are well-known as spoilage organisms in both the wine and beer industries, but also contribute important desirable characters to certain beer styles. These properties are mediated in large part by Brettanomyces ' metabolism of hydroxycinnamic acids (HCAs) present in beverage raw materials. Here we compare growth inhibition by, and metabolism of, HCAs among commercial brewing strains and spoilage strains of B. bruxellensis and B. anomalus . These properties vary widely among the different strains tested and between the HCAs analyzed. Brewing strains showed more efficient metabolism of ferulic acid over p -coumaric acid, a trait not shared among the spoilage strains.

The effect of bacteriocin-producing Lactobacillus plantarum strains on the intracellular pH of sessile and planktonic Listeria monocytongenes single cells

DEFF Research Database (Denmark)

Nielsen, Dennis Sandris; Cho, Gyu-Sung; Hanak, Alexander

2010-01-01

and/or bacteriocin-producing LAB as “natural” food preservatives in foods such as cheese, meat and ready-to-eat products. Some strains of Lactobacillus plantarum produce bacteriocins termed plantaricins. Using a single-cell based approach, the effect on the intracellular pH as a measure......A wide range of lactic acid bacteria (LAB) produce bacteriocins mainly active against other closely related LAB, but some bacteriocins are also active against the food-borne pathogen Listeria monocytogenes. With the aim of increasing food safety it has thus been considered to utilise bacteriocins...

Inhibition of food-related bacteria by antibacterial substances produced by Pseudomonas sp. strains isolated from pasteurized milk

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Ana Beatriz Ferreira Rangel

2013-12-01

Full Text Available In this work, the production of antimicrobial substances by strains of Pseudomonas sp. isolated from pasteurized milk and their potential action against food-related bacteria were investigated. Samples of pasteurized milk were purchased from arbitrarily chosen commercial establishments in the city of Rio de Janeiro, Brazil. Of the four samples analyzed, three presented several typical colonies of Pseudomonas. About 100 colonies were chosen and subjected to biochemical tests for confirmation of their identity. Eighteen strains of the Pseudomonas genus were identified and submitted to tests for the production of antimicrobial substances. Twelve strains (66.7% were identified as Pseudomonas fluorescens, four (22.2% as P. aeruginosa, one (5.5% as P. mendocina and one (5.5% as P. pseudoalcaligenes. Only two P. fluorescens strains were unable to produce any antimicrobial substance against any of the indicator strains tested. Most of the strains presented a broad spectrum of action, inhibiting reference and food-related strains such as Proteus vulgaris, Proteus mirabilis, Hafnia alvei, Yersinia enterocolitica, Escherichia coli and Salmonella typhi. Five antimicrobial substance-producing strains, which presented the broadest spectrum of action, were also tested against Staphylococcus aureus reference strains and 26 Staphylococcus sp. strains isolated from foods, some of which were resistant to antibiotics. The producer strains 8.1 and 8.3, both P. aeruginosa, were able to inhibit all the staphylococcal strains tested. The antimicrobial substances produced by strains 8.1 and 8.3 did not seem to be typical bacteriocins, since they were resistant to the three proteolytic enzymes tested. Experiments involving the characterization of these substances are being carried out in order to evaluate their biotechnological application.

Cyclopiazonic Acid Biosynthesis of Aspergillus flavus and Aspergillus oryzae

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Cyclopiazonic acid (CPA) is an indole-tetramic acid neurotoxin produced by some of the same strains of A. flavus that produce aflatoxins and by some Aspergillus oryzae strains. Despite its discovery 40 years ago, few reviews of its toxicity and biosynthesis have been reported. This review examines w...

Antagonistic effect of chosen lactic acid bacteria strains on Salmonella species in meat and fermented sausages.

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Gomółka-Pawlicka, M; Uradziński, J

2003-01-01

The aim of this study was to determine of influence of 15 strains of lactic acid bacteria on the growth of 7 Salmonella spp. strains in model set-ups, and in meat and ripened fermented sausages. The investigations were performed within the framework of three alternate stages which differed in respect to the products studied, the number of Lactobacillus spp. strains and, partly, methodological approach. The ratio between lactic acid bacteria and Salmonella strains studied was, depending on the alternate, 1:1, 1:2 and 2:1, respectively. The investigations also covered the water activity (a(w)) and pH of the tested products. The results obtained are shown in 12 figures and suggest that all the lactic acid bacteria strains used within the framework of the model set-ups showed antagonistic effect on all the Salmonella spp. strains. However, these abilities were not observed with respect to some lactic acid bacteria strains in meat and fermented sausage. The temperature and length of the incubation period of sausages, but not a(w) and pH, were found to have a distinct influence on the antagonistic interaction between the bacteria.

Mesophilic Lactic Acid Bacteria Diversity Encountered in Brazilian Farms Producing Milk with Particular Interest in Lactococcus lactis Strains.

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Luiz, L M P; Chuat, V; Madec, M N; Araújo, E A; de Carvalho, A F; Valence, F

2016-10-01

The milk produced in regions with different traditions in Brazil is used for artisanal product production, which is characterized by different sensorial characteristics. This study aimed to identify the bacterial ecosystem of farms located in a traditional dairy region in the state of Minas Gerais and to characterize Lactococcus lactis strains, the species of interest in this study, using a multilocus sequence typing (MLST) protocol and pulsed-field gel electrophoresis (PFGE) technique. Samples were collected from raw milk and dairy environment from six farms. A total of 50 isolates were analyzed using 16S rRNA sequencing and species-specific PCR. Five genera were identified: Lactobacillus, Leuconostoc, Lactococcus, Enterococcus, and Staphylococcus, from ten different species. MLST (with six housekeeping genes) and PFGE (with SmaI endonuclease) were used for the characterization of 20 isolates of Lactococcus lactis from a dairy collection in this study. Both methods revealed a high clonal diversity of strains with a higher discriminatory level for PFGE (15 pulsotypes), compared to MLST (12 ST). This study contributes to the preservation of the Brazilian dairy heritage and provides insights into a part of the LAB population found in raw milk and dairy environment.

Novel comprehensive multidimensional liquid chromatography approach for elucidation of the microbosphere of shikimate-producing Escherichia coli SP1.1/pKD15.071 strain.

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Cacciola, Francesco; Mangraviti, Domenica; Rigano, Francesca; Donato, Paola; Dugo, Paola; Mondello, Luigi; Cortes, Hernan J

2018-06-01

Shikimic acid is a intermediate of aromatic amino acid biosynthesis and the preferred starting material for production of the most commonly prescribed anti-influenza drug, Tamiflu. Its six-membered carbocyclic ring is adorned with several chiral centers and various functionalities, making shikimic acid a valuable chiral synthon. When microbially-produced, in addition to shikimic acid, numerous other metabolites are exported out of the cytoplasm and accumulate in the culture medium. This extracellular matrix of metabolites is referred to as the microbosphere. Due to the high sample complexity, in this study, the microbosphere of shikimate-producing Escherichia coli SP1.1/pKD15.071 was analyzed by liquid chromatography and comprehensive two-dimensional liquid chromatography coupled to photodiode array and mass spectrometry detection. GC analysis of the trimethylsilyl derivatives was also carried out in order to support the elucidation of the selected metabolites in the microbosphere. The elucidation of the metabolic fraction of this bacterial strain might be of valid aid for improving, through genetic changes, the concentration and yield of shikimic acid synthesized from glucose. Graphical abstract.

Direct lactic acid fermentation of Jerusalem artichoke tuber extract using Lactobacillus paracasei without acidic or enzymatic inulin hydrolysis.

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Choi, Hwa-Young; Ryu, Hee-Kyoung; Park, Kyung-Min; Lee, Eun Gyo; Lee, Hongweon; Kim, Seon-Won; Choi, Eui-Sung

2012-06-01

Lactic acid fermentation of Jerusalem artichoke tuber was performed with strains of Lactobacillus paracasei without acidic or enzymatic inulin hydrolysis prior to fermentation. Some strains of L. paracasei, notably KCTC13090 and KCTC13169, could ferment hot-water extract of Jerusalem artichoke tuber more efficiently compared with other Lactobacillus spp. such as L. casei type strain KCTC3109. The L. paracasei strains could utilize almost completely the fructo-oligosaccharides present in Jerusalem artichoke. Inulin-fermenting L. paracasei strains produced c.a. six times more lactic acid compared with L. casei KCTC3109. Direct lactic fermentation of Jerusalem artichoke tuber extract at 111.6g/L of sugar content with a supplement of 5 g/L of yeast extract by L. paracasei KCTC13169 in a 5L jar fermentor produced 92.5 ce:hsp sp="0.25"/>g/L of lactic acid with 16.8 g/L fructose equivalent remained unutilized in 72 h. The conversion efficiency of inulin-type sugars to lactic acid was 98% of the theoretical yield. Copyright © 2012 Elsevier Ltd. All rights reserved.

Analysis of antimicrobial and immunomodulatory substances produced by heterofermentative Lactobacillus reuteri.

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Greifová, Gabriela; Májeková, Hyacinta; Greif, Gabriel; Body, Patrik; Greifová, Maria; Dubničková, Martina

2017-11-01

Antimicrobial and immunomodulatory potential of various Lactobacillus reuteri strains is closely connected to their metabolite production profile under given cultivation conditions. We determined the in vitro production of antimicrobial substances such as organic acids, ethanol, and reuterin by four strains of L. reuteri (L. reuteri E, L. reuteri KO5, L. reuteri CCM 3625, and L. reuteri ATCC 55730). All studied L. reuteri strains showed the ability to produce lactic acid, acetic acid, and ethanol with concominant consumption of glucose and together with phenyllactic acid-a potent antifungal compound-with concominant consumption of phenylalanine. The reuterin production from glycerol was confirmed for all analyzed lactobacilli strains except L. reuteri CCM 3625. Production of organic acids, ethanol, and reuterin is significantly involved in antimicrobial activity of lactobacilli which was determined using the dual-culture overlay diffusion method against six indicator bacteria and five indicator moulds. In comparison to the referential L. reuteri ATCC 55730, the highest inhibition potential was observed against Escherichia coli CCM 3988 and Pseudomonas aeruginosa CCM 3955. Among analyzed indicators of moulds, the growth of Alternaria alternata CCM F-128 was the most inhibited by all four analyzed L. reuteri strains. Finally, the immunomodulatory potential of analyzed lactobacilli were proven by the determination of the in vitro production of biogenic amines histamine and tyramine. L. reuteri CCM 3625 was able to produce tyramine, and L. reuteri E and L. reuteri KO5 were able to produce histamine under given cultivation conditions.

Employing a Recombinant Strain of Advenella mimigardefordensis for Biotechnical Production of Homopolythioesters from 3,3′-Dithiodipropionic Acid

Science.gov (United States)

Xia, Yongzhen; Wübbeler, Jan Hendrik; Qi, Qingsheng

2012-01-01

Advenella mimigardefordensis strain DPN7T was genetically modified to produce poly(3-mercaptopropionic acid) (PMP) homopolymer by exploiting the recently unraveled process of 3,3′-dithiodipropionic acid (DTDP) catabolism. Production was achieved by systematically engineering the metabolism of this strain as follows: (i) deletion of its inherent 3MP dioxygenase-encoding gene (mdo), (ii) introduction of the buk-ptb operon (genes encoding the butyrate kinase, Buk, and the phosphotransbutyrylase, Ptb, from Clostridium acetobutylicum), and (iii) overexpression of its own polyhydroxyalkanoate synthase (phaCAm). These measures yielded the potent PMP production strain A. mimigardefordensis strain SHX22. The deletion of mdo was required for adequate synthesis of PMP due to the resulting accumulation of 3MP during utilization of DTDP. Overexpression of the plasmid-borne buk-ptb operon caused a severe growth repression. This effect was overcome by inserting this operon into the genome. Polyhydroxyalkanoate (PHA) synthases from different origins were compared. The native PHA synthase of A. mimigardefordensis (phaCAm) was obviously the best choice to establish homopolythioester production in this strain. In addition, the cultivation conditions, including an appropriate provision of the carbon source, were further optimized to enhance PMP production. The engineered strain accumulated PMP up to approximately 25% (wt/wt) of the cell dry weight when cultivated in mineral salts medium containing glycerol as the carbon source in addition to DTDP as the sulfur-providing precursor. According to our knowledge, this is the first report of PMP homopolymer production by a metabolically engineered bacterium using DTDP, which is nontoxic, as the precursor substrate. PMID:22344658

Modulation of allergic immune responses by mucosal application of recombinant lactic acid bacteria producing the major birch pollen allergen Bet v 1.

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Daniel, C; Repa, A; Wild, C; Pollak, A; Pot, B; Breiteneder, H; Wiedermann, U; Mercenier, A

2006-07-01

Probiotic lactic acid bacteria (LAB) are able to modulate the host immune system and clinical trials have demonstrated that specific strains have the capacity to reduce allergic symptoms. Therefore, we aimed to evaluate the potential of recombinant LAB producing the major birch pollen allergen Bet v 1 for mucosal vaccination against birch pollen allergy. Recombinant Bet v 1-producing Lactobacillus plantarum and Lactococcus lactis strains were constructed. Their immunogenicity was compared with purified Bet v 1 by subcutaneous immunization of mice. Intranasal application of the live recombinant strains was performed to test their immunomodulatory potency in a mouse model of birch pollen allergy. Bet v 1 produced by the LAB was recognized by monoclonal anti-Bet v 1 and IgE antibodies from birch pollen-allergic patients. Systemic immunization with the recombinant strains induced significantly lower IgG1/IgG2a ratios compared with purified Bet v 1. Intranasal pretreatment led to reduced allergen-specific IgE vs enhanced IgG2a levels and reduced interleukin (IL)-5 production of splenocytes in vitro, indicating a shift towards non-allergic T-helper-1 (Th1) responses. Airway inflammation, i.e. eosinophils and IL-5 in lung lavages, was reduced using either Bet v 1-producing or control strains. Allergen-specific secretory IgA responses were enhanced in lungs and intestines after pretreatment with only the Bet v 1-producing strains. Mucosal vaccination with live recombinant LAB, leading to a shift towards non-allergic immune responses along with enhanced allergen-specific mucosal IgA levels offers a promising approach to prevent systemic and local allergic immune responses.

Analysis of Growth Inhibition and Metabolism of Hydroxycinnamic Acids by Brewing and Spoilage Strains of Brettanomyces Yeast

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Michael Lentz

2015-10-01

Full Text Available Brettanomyces yeasts are well-known as spoilage organisms in both the wine and beer industries, but also contribute important desirable characters to certain beer styles. These properties are mediated in large part by Brettanomyces’ metabolism of hydroxycinnamic acids (HCAs present in beverage raw materials. Here we compare growth inhibition by, and metabolism of, HCAs among commercial brewing strains and spoilage strains of B. bruxellensis and B. anomalus. These properties vary widely among the different strains tested and between the HCAs analyzed. Brewing strains showed more efficient metabolism of ferulic acid over p-coumaric acid, a trait not shared among the spoilage strains.

Selection of lactic acid bacteria able to ferment inulin hydrolysates

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Octavian BASTON

2012-12-01

Full Text Available Eight homofermentative lactic acid bacteria isolates were tested for lactic acid production using chicory and Jerusalem artichoke hydrolysate as substrate. The pH, lactic acid yield and productivity were used to select the best homolactic bacteria for lactic acid production. The selected strains produced lactic acid at maximum yield after 24 hours of fermentation and the productivity was greater at 24 hours of fermentation. From all studied strains, Lb1 and Lb2 showed the best results regarding lactic acid yields andproductivity. After 48 hours of chicory and Jerusalem artichhoke hydrolysates fermentation, from all the studied strains, Lb2 produced the highest lactic acid yield (0.97%. Lb2 produced after 48 hours of fermentation the lowest pH value of 3.45±0.01. Lb2 showed greater lactic acid productivity compared to the other studied lactic acid bacteria, the highest values, 0.13 g·L-1·h-1fromJerusalem artichoke hydrolysate and 0.11g·L-1·h-1 from chicory hydrolysate, being produced after 24 hours of fermentation.

Molecular Detection of Aflatoxin Producing Strains of Aspergillus Flavus from Peanut (Arachis Hypogaea

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Adeela Hussain

2015-02-01

Full Text Available Aflatoxins are the potential carcinogens produced as secondary metabolites by Aspergillus flavus. They have the ability to contaminate large number of food which ultimately affect the human population. Malt extract agar was selected for the growth of control stains of fungus. The aim of the study was to develop a reliable and quick method for the detection of aflatoxin producing strains in peanuts by using molecular approaches. Total 80 samples of infected peanuts were collected from four different cities of Punjab and checked for their aflatoxin contamination. For aflatoxin detection, three target genes nor1, ver1 and aflR were selected which was involved in the aflatoxin biosynthesis. In all examined cases, 24 out of 80 (30% samples successfully amplified all three genes indicating aflatoxigenic activity. Discrimination between aflatoxigenic and non-aflatoxigenic strains were also determined on the basis of amplification of these three target DNA fragments. In this study, it was also demonstrated that only specific strains were able to produce the aflatoxin contamination in peanuts.

Bioremediation of acid mine drainage using algae strains: A review

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J.K. Bwapwa

2017-12-01

Full Text Available Acid mine drainage (AMD causes massive environmental concerns worldwide. It is highly acidic and contains high levels of heavy metals causing environmental damage. Conventional treatment methods may not be effective for AMD. The need for environmental remediation requires cost effective technologies for efficient removal of heavy metals. In this study, algae based systems were reviewed and analyzed to point out the potentials and gaps for future studies. Algae strains such as Spirulina sp., Chlorella, Scenedesmus, Cladophora, Oscillatoria, Anabaena, Phaeodactylum tricornutum have showed the capacity to remove a considerable volume of heavy metals from AMD. They act as “hyper-accumulators” and “hyper-adsorbents” with a high selectivity for different elements. In addition, they generate high alkalinity which is essential for precipitation of heavy metals during treatment. However, algae based methods of abating AMD are not the ultimate solution to the problem and there is room for more studies. : The bioremediation of acid mine drainage is achievable with the use of microalgae. Keywords: Acid mine drainage, Algae strains, Contamination, Heavy metals, Bioremediation

Acid and bile tolerance of spore-forming lactic acid bacteria.

Science.gov (United States)

Hyronimus, B; Le Marrec, C; Sassi, A H; Deschamps, A

2000-11-01

Criteria for screening probiotics such as bile tolerance and resistance to acids were studied with 13 spore-forming lactic acid producing bacteria. Different strains of Sporolactobacillus, Bacillus laevolacticus, Bacillus racemilacticus and Bacillus coagulans grown in MRS broth were subjected to low pH conditions (2, 2.5 and 3) and increasing bile concentrations. Among these microorganisms, Bacillus laevolacticus DSM 6475 and all Sporolactobacillus strains tested except Sporolactobacillus racemicus IAM 12395, were resistant to pH 3. Only Bacillus racemilacticus and Bacillus coagulans strains were tolerant to bile concentrations over 0.3% (w/v).

Use of Fatty Acid Methyl Ester Profiles to Compare Copper-Tolerant and Copper-Sensitive Strains of Pantoea ananatis.

Science.gov (United States)

Nischwitz, C; Gitaitis, R; Sanders, H; Langston, D; Mullinix, B; Torrance, R; Boyhan, G; Zolobowska, L

2007-10-01

ABSTRACT A survey was conducted to evaluate differences in fatty acid methyl ester (FAME) profiles among strains of Pantoea ananatis, causal agent of center rot of onion (Allium cepa), isolated from 15 different onion cultivars in three different sites in Georgia. Differences in FAME composition were determined by plotting principal components (PCs) in two-dimensional plots. Euclidean distance squared (ED(2)) values indicated a high degree of similarity among strains. Plotting of PCs calculated from P. ananatis strains capable of growing on media amended with copper sulfate pentahydrate (200 mug/ml) indicated that copper-tolerant strains grouped into tight clusters separate from clusters formed by wild-type strains. However, unlike copper-sensitive strains, the copper-tolerant strains tended to cluster by location. A total of 80, 60, and 73% of the strains from Tift1, Tift2, and Tattnall, respectively, exhibited either confluent growth or partial growth on copper-amended medium. However, all strains were sensitive to a mixture of copper sulfate pentahydrate (200 mug/ml) and maneb (40 mug/ml). When copper-tolerant clones were analyzed and compared with their wild-type parents, in all cases the plotting of PCs developed from copper-tolerant clones formed tight clusters separate from clusters formed by the parents. Eigenvalues generated from these tests indicated that two components provided a good summary of the data, accounting for 98, 98, and 96% of the standardized variance for strains Pna 1-15B, Pna 1-12B, and Pna 2-5A, respectively. Furthermore, feature 4 (cis-9-hexadecenoic acid/2-hydroxy-13-methyltetradecanoic acid) and feature 7 (cis-9/trans-12/cis-7-octadecenoic acid) were the highest or second highest absolute values for PC1 in all three strains of the parents versus copper-tolerant clones, and hexadecanoic acid was the highest absolute value for PC2 in all three strains. Along with those fatty acids, dodecanoic acid and feature 3 (3-hydroxytetradecanoic

Highly Efficient Biotransformation of Eugenol to Ferulic Acid and Further Conversion to Vanillin in Recombinant Strains of Escherichia coli

Science.gov (United States)

Overhage, Jörg; Steinbüchel, Alexander; Priefert, Horst

2003-01-01

The vaoA gene from Penicillium simplicissimum CBS 170.90, encoding vanillyl alcohol oxidase, which also catalyzes the conversion of eugenol to coniferyl alcohol, was expressed in Escherichia coli XL1-Blue under the control of the lac promoter, together with the genes calA and calB, encoding coniferyl alcohol dehydrogenase and coniferyl aldehyde dehydrogenase of Pseudomonas sp. strain HR199, respectively. Resting cells of the corresponding recombinant strain E. coli XL1-Blue(pSKvaomPcalAmcalB) converted eugenol to ferulic acid with a molar yield of 91% within 15 h on a 50-ml scale, reaching a ferulic acid concentration of 8.6 g liter−1. This biotransformation was scaled up to a 30-liter fermentation volume. The maximum production rate for ferulic acid at that scale was 14.4 mmol per h per liter of culture. The maximum concentration of ferulic acid obtained was 14.7 g liter−1 after a total fermentation time of 30 h, which corresponded to a molar yield of 93.3% with respect to the added amount of eugenol. In a two-step biotransformation, E. coli XL1-Blue(pSKvaomPcalAmcalB) was used to produce ferulic acid from eugenol and, subsequently, E. coli(pSKechE/Hfcs) was used to convert ferulic acid to vanillin (J. Overhage, H. Priefert, and A. Steinbüchel, Appl. Environ. Microbiol. 65:4837-4847, 1999). This process led to 0.3 g of vanillin liter−1, besides 0.1 g of vanillyl alcohol and 4.6 g of ferulic acid liter−1. The genes ehyAB, encoding eugenol hydroxylase of Pseudomonas sp. strain HR199, and azu, encoding the potential physiological electron acceptor of this enzyme, were shown to be unsuitable for establishing eugenol bioconversion in E. coli XL1-Blue. PMID:14602615

MUTANT STRAIN of Bacillus subtilis IFBG MC-1 WITH INCREASED TRYPTOPHAN SYNTHESIS

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A. F. Tkachenko

2013-12-01

Full Text Available Scientific research of essential amino acids biotechnology is directed both to create optimum conditions for producer’s cultivation and economically viable raw materials selection for these technologies, so as breeding the more productive microorganisms strains capable of extracellular producing amino acids. For successful microbial synthesis it is necessary to have an excellent crop’s metabolism knowledge and ensure that the composition of growth medium have no repressing substances. Bacterial cultures from «Collection microorganism’s stains and plants line for food and agriculture biotechnology» from Institute of Food Biotechnology and Genomics of National Academy of Sciences of Ukraine have been studied. Tryptophan producer Bacillus subtilis have been selected, which accumulated the greatest amount of this amino acid in the cultivation liquid. The optimal culture producer conditions were selected. Using selection methods, namely mutagenesis with UV irradiation and sequential stepwise selection, mutant strain Bacillus subtilis IFBG MC-1 were obtained which produced nearly 50% more tryptophan (13.9 g/l than the parent strain.

Citric acid production and citrate synthase genes in distinct strains of ...

African Journals Online (AJOL)

Citric acid is an important organic acid, multifunctional with a wide array of uses. The objectives of this study were the isolation and selection strains of the genus Aspergillus, investigating the solubilization of phosphate of these isolates, verifying the expression rate of genes involved in the identification of isolates, and ...

Fatty acid production by four strains of Mucor hiemalis grown in plant ...

African Journals Online (AJOL)

SERVER

2007-08-06

Aug 6, 2007 ... Four Mucor hiemalis strains (M1, M2, M3 and M4), isolated from soil at a depth of 0 - 15 ... Plant oils were inhibitors of fatty acid production by these strains. .... The procedure was adapted from Kates (1982) and Kennedy et al.

Revealing differences in metabolic flux distributions between a mutant strain and its parent strain Gluconacetobacter xylinus CGMCC 2955.

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Cheng Zhong

Full Text Available A better understanding of metabolic fluxes is important for manipulating microbial metabolism toward desired end products, or away from undesirable by-products. A mutant strain, Gluconacetobacter xylinus AX2-16, was obtained by combined chemical mutation of the parent strain (G. xylinus CGMCC 2955 using DEC (diethyl sulfate and LiCl. The highest bacterial cellulose production for this mutant was obtained at about 11.75 g/L, which was an increase of 62% compared with that by the parent strain. In contrast, gluconic acid (the main byproduct concentration was only 5.71 g/L for mutant strain, which was 55.7% lower than that of parent strain. Metabolic flux analysis indicated that 40.1% of the carbon source was transformed to bacterial cellulose in mutant strain, compared with 24.2% for parent strain. Only 32.7% and 4.0% of the carbon source were converted into gluconic acid and acetic acid in mutant strain, compared with 58.5% and 9.5% of that in parent strain. In addition, a higher flux of tricarboxylic acid (TCA cycle was obtained in mutant strain (57.0% compared with parent strain (17.0%. It was also indicated from the flux analysis that more ATP was produced in mutant strain from pentose phosphate pathway (PPP and TCA cycle. The enzymatic activity of succinate dehydrogenase (SDH, which is one of the key enzymes in TCA cycle, was 1.65-fold higher in mutant strain than that in parent strain at the end of culture. It was further validated by the measurement of ATPase that 3.53-6.41 fold higher enzymatic activity was obtained from mutant strain compared with parent strain.

Lactic Acid Production from Pretreated Hydrolysates of Corn Stover by a Newly Developed Bacillus coagulans Strain

OpenAIRE

Jiang, Ting; Qiao, Hui; Zheng, Zhaojuan; Chu, Qiulu; Li, Xin; Yong, Qiang; Ouyang, Jia

2016-01-01

An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP) mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH) of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH), condensed acid-catalyzed liquid hot water hydrolysate (CALH) and condensed acid-...

In vitro evaluation of immunological properties of extracellular polysaccharides produced by Lactobacillus delbrueckii strains.

Science.gov (United States)

Kishimoto, Mana; Nomoto, Ryohei; Osawa, Ro

2015-01-01

We investigated the variation in immunological properties of the extracellular polysaccharides (EPSs) produced by different Lactobacillus delbrueckii strains as well as that of their monosaccharide composition. The monosaccharide composition of each EPS produced by L. delbrueckii strains, as determined by thin layer chromatography (TLC), showed an appreciable variation in a strain-dependent manner, which could be broadly assigned to 4 TLC groups. Meanwhile, the immunological properties of the EPSs produced by 10 L. delbrueckii strains were evaluated in a semi-intestinal model using a Transwell co-culture system, which employed human intestinal epithelial Caco-2 cells on the apical side and murine macrophage RAW264.7 cells on the basolateral side. Each EPS was added to the apical side to allow direct contact with Caco-2 cells and incubated for 6 hr. After incubation, the amounts of TNF-α and several cytokines that had been released by either RAW264.7 or Caco-2 cells were then quantified by cytotoxic activity on L929 cells or the RT-PCR method. It was found that the EPS-stimulated RAW264.7 cells express different profiles of cytokine production via Caco-2 cells but that the profile difference could not be related to the above TLC grouping. The evidence suggests that the EPSs of L. delbrueckii strains are diverse not only in their biochemical structure but also in their immunological properties.

Producing Acetic Acid of Acetobacter pasteurianus by Fermentation Characteristics and Metabolic Flux Analysis.

Science.gov (United States)

Wu, Xuefeng; Yao, Hongli; Liu, Qing; Zheng, Zhi; Cao, Lili; Mu, Dongdong; Wang, Hualin; Jiang, Shaotong; Li, Xingjiang

2018-03-19

The acetic acid bacterium Acetobacter pasteurianus plays an important role in acetic acid fermentation, which involves oxidation of ethanol to acetic acid through the ethanol respiratory chain under specific conditions. In order to obtain more suitable bacteria for the acetic acid industry, A. pasteurianus JST-S screened in this laboratory was compared with A. pasteurianus CICC 20001, a current industrial strain in China, to determine optimal fermentation parameters under different environmental stresses. The maximum total acid content of A. pasteurianus JST-S was 57.14 ± 1.09 g/L, whereas that of A. pasteurianus CICC 20001 reached 48.24 ± 1.15 g/L in a 15-L stir stank. Metabolic flux analysis was also performed to compare the reaction byproducts. Our findings revealed the potential value of the strain in improvement of industrial vinegar fermentation.

CHARACTERIZATION OF A NEW BACILLUS-STEAROTHERMOPHILUS ISOLATE - A HIGHLY THERMOSTABLE ALPHA-AMYLASE-PRODUCING STRAIN

NARCIS (Netherlands)

WIND, RD; BUITELAAR, RM; EGGINK, G; HUIZING, HJ; DIJKHUIZEN, L

A novel strain of Bacillus stearothermophilus was isolated from samples of a potato-processing industry. Compared to known alpha-amylases from other B. stearothermophilus strains, the isolate was found to produce a highly thermostable alpha-amylase. The half-time of inactivation of this

Purification of bacteriocins produced by lactic acid bacteria.

Science.gov (United States)

Saavedra, Lucila; Castellano, Patricia; Sesma, Fernando

2004-01-01

Bacteriocins are antibacterial substances of a proteinaceous nature that are produced by different bacterial species. Lactic acid bacteria (LAB) produce biologically active peptides or protein complexes that display a bactericidal mode of action almost exclusively toward Gram-positive bacteria and particularly toward closely related species. Generally they are active against food spoilage and foodborne pathogenic microorganisms including Bacillus cereus, Clostridium perfringens, Staphylococcus aureus, and Listeria monocytogenes. There is an increased tendency to use natural occurring metabolites to prevent the growth of undesirable flora in foodstuffs. These metabolites could replace the use of chemical additives such as sorbic acid, sulfur dioxide, nitrite, nitrate, and others. For instance, bacteriocins produced by LAB may be promising for use as bio-preservaties. Bacteriocins of lactic acid bacteria are typically cationic, hydrophobic peptides and differ widely in many characteristics including molecular weight, presence of particular groups of amino acids, pI, net positive charge, and post-translational modifications of certain amino acids. This heterogeneity within the LAB bacteriocins may explain the different procedures for isolation and purification developed so far. The methods most frequently used for isolation, concentration, and purification involve salt precipitation of bacteriocins from culture supernatants, followed by various combinations of gel filtration, ion-exchange chromatography, and reverse-phase high-performance liquid chromatography (RP-HPLC). In this chapter, a protocol is described that combines several methods used in our laboratory for the purification of two cationic bacteriocins, Lactocin 705AL and Enterocin CRL10, produced by Lactobacillus casei CRL705 and Enterococcus mundtii CRL10, respectively.

Polyamic Acid Nanofibers Produced by Needleless Electrospinning

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Oldrich Jirsak

2010-01-01

Full Text Available The polyimide precursor (polyamic acid produced of 4,4′-oxydiphthalic anhydride and 4,4′-oxydianiline was electrospun using needleless electrospinning method. Nonwoven layers consisting of submicron fibers with diameters in the range about 143–470 nm on the polypropylene spunbond supporting web were produced. Filtration properties of these nanofiber layers on the highly permeable polypropylene support—namely filtration effectivity and pressure drop—were evaluated. Consequently, these polyamic acid fibers were heated to receive polyimide nanofibers. The imidization process has been studied using IR spectroscopy. Some comparisons with the chemically identical polyimide prepared as the film were made.

Malic acid production from thin stillage by Aspergillus species.

Science.gov (United States)

West, Thomas P

2011-12-01

The ability of Aspergillus strains to utilize thin stillage to produce malic acid was compared. The highest malic acid was produced by Aspergillus niger ATCC 9142 at 17 g l(-1). Biomass production from thin stillage was similar with all strains but ATCC 10577 was the highest at 19 g l(-1). The highest malic acid yield (0.8 g g(-1)) was with A. niger ATCC 9142 and ATCC 10577 on the stillage. Thus, thin stillage has the potential to act as a substrate for the commercial production of food-grade malic acid by the A. niger strains. © Springer Science+Business Media B.V. 2011

Probiotic properties of endemic strains of lactic acid bacteria

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Flora N. Tkhruni

2013-01-01

Full Text Available Strains of lactic acid bacteria (LAB isolated from various samples of matsun, yogurt and salted cheese from natural farms of Armenia were studied. They have high antimicrobial and probiotic activities, growth rate and differ by their resistance to enzymes. Supernatants of LAB retain bactericidal activity at рН 3.0-8.0 and inhibit growth of various microflora. The application of different methods of identification and LAB genotyping (API 50 CH, 16S rRNA sequencing, GS-PCR, RAPD PCR showed that isolated LAB evidenced a 99.9% similarity with L. rhamnosus, L. plantarum and L. pentosus species and coccoid forms of Streptococcus and Enterococcus species. It can be concluded, that some strains of lactic acid bacteria, isolated from dairy products from natural farms of Armenia, can be properly used for biopreservation of some foodstuffs. On the basis of experimental data, the LAB can be used as basis for obtaining the new products of functional nutrition.

Morphological characterization of recombinant strains of Aspergillus oryzae producing alpha-amylase during batch cultivations

DEFF Research Database (Denmark)

Spohr, Anders Bendsen; Carlsen, Morten; Nielsen, Jens Bredal

1997-01-01

Three alpha-amylase producing strains of Aspergillus oryzae used for recombinant protein production have been studied with respect to growth and protein production. By comparing the three strains with respect to morphology and protein production it is shown that a morphological mutant with a more...

Physiological characterization of the high malic acid-producing Aspergillus oryzae strain 2103a-68

DEFF Research Database (Denmark)

Knuf, Christoph; Nookaew, Intawat; Remmers, Ilse

2014-01-01

Malic acid is a C4 dicarboxylic acid that is currently mainly used in the food and beverages industry as an acidulant. Because of the versatility of the group of C4 dicarboxylic acids, the chemical industry has a growing interest in this chemical compound. As malic acid will be considered as a bulk...

Potential of Rhodococcus strains for biotechnological vanillin production from ferulic acid and eugenol.

Science.gov (United States)

Plaggenborg, Rainer; Overhage, Jörg; Loos, Andrea; Archer, John A C; Lessard, Philip; Sinskey, Anthony J; Steinbüchel, Alexander; Priefert, Horst

2006-10-01

The potential of two Rhodococcus strains for biotechnological vanillin production from ferulic acid and eugenol was investigated. Genome sequence data of Rhodococcus sp. I24 suggested a coenzyme A-dependent, non-beta-oxidative pathway for ferulic acid bioconversion, which involves feruloyl-CoA synthetase (Fcs), enoyl-CoA hydratase/aldolase (Ech), and vanillin dehydrogenase (Vdh). This pathway was proven for Rhodococcus opacus PD630 by physiological characterization of knockout mutants. However, expression and functional characterization of corresponding structural genes from I24 suggested that degradation of ferulic acid in this strain proceeds via a beta-oxidative pathway. The vanillin precursor eugenol facilitated growth of I24 but not of PD630. Coniferyl aldehyde was an intermediate of eugenol degradation by I24. Since the genome sequence of I24 is devoid of eugenol hydroxylase homologous genes (ehyAB), eugenol bioconversion is most probably initiated by a new step in this bacterium. To establish eugenol bioconversion in PD630, the vanillyl alcohol oxidase gene (vaoA) from Penicillium simplicissimum CBS 170.90 was expressed in PD630 together with coniferyl alcohol dehydrogenase (calA) and coniferyl aldehyde dehydrogenase (calB) genes from Pseudomonas sp. HR199. The recombinant strain converted eugenol to ferulic acid. The obtained data suggest that genetically engineered strains of I24 and PD630 are suitable candidates for vanillin production from eugenol.

Synergism between hydrogen peroxide and seventeen acids against five agri-food-borne fungi and one yeast strain.

Science.gov (United States)

Martin, H; Maris, P

2012-12-01

The objective of this study was to evaluate fungicidal efficacy of hydrogen peroxide administered in combination with 17 mineral and organic acids authorized for use in the food industry. The assays were performed on a 96-well microplate using a microdilution technique based on the checkerboard titration method. The six selected strains (one yeast and five fungi) were reference strains and strains representative of contaminating fungi found in the food industry. Each synergistic hydrogen peroxide/acid combination found after fifteen minutes contact time at 20 °C in distilled water was then tested in conditions simulating four different use conditions. Twelve combinations were synergistic in distilled water, eleven of these remained synergistic with one or more of the four mineral and organic interfering substances selected. Hydrogen peroxide/formic acid combination remained effective against four strains and was never antagonistic against the other two fungi. Combinations with propionic acid and acetic acid stayed synergistic against two strains. Those with oxalic acid and lactic acid kept their synergism only against Candida albicans. No synergism was detected against Penicillium cyclopium. Synergistic combinations of disinfectants were revealed, among them the promising hydrogen peroxide/formic acid combination. A rapid screening method developed in our laboratory for bacteria was adapted to fungi and used to reveal the synergistic potential of disinfectants and/or sanitizers combinations. © 2012 The Society for Applied Microbiology.

Modeling of the stress-strain state of the ground mass contaminated with peracetic acid

Directory of Open Access Journals (Sweden)

Levenko Anna

2017-01-01

Full Text Available None of the methods described previously provides a solution to the problem that deals with the SSS evaluation of the ground mass which is under the influence of chemically active substances and, in particular, under the influence of peracetic acid. The stress-strain state of the ground mass contaminated with peracetic acid was estimated. Stresses occurring in the ground mass in the natural state were determined after the entry of acid into it and after the chemical fixation of it with sodium silicate. All the parameters of the stress-strain state of the ground mass were obtained under a number of physical and mechanical conditions. It was determined that following the work on the silicatization of the ground mass contaminated with peracetic acid the quantity of strain decreased by 26.11 to 48.9%. The comparison of the results of stress calculations indicates the stress reduction in the ground mass in 1.8 – 2.6 times after its fixing.

Genealogy profiling through strain improvement by using metabolic network analysis: metabolic flux genealogy of several generations of lysine-producing corynebacteria.

Science.gov (United States)

Wittmann, Christoph; Heinzle, Elmar

2002-12-01

A comprehensive approach of metabolite balancing, (13)C tracer studies, gas chromatography-mass spectrometry, matrix-assisted laser desorption ionization-time of flight mass spectrometry, and isotopomer modeling was applied for comparative metabolic network analysis of a genealogy of five successive generations of lysine-producing Corynebacterium glutamicum. The five strains examined (C. glutamicum ATCC 13032, 13287, 21253, 21526, and 21543) were previously obtained by random mutagenesis and selection. Throughout the genealogy, the lysine yield in batch cultures increased markedly from 1.2 to 24.9% relative to the glucose uptake flux. Strain optimization was accompanied by significant changes in intracellular flux distributions. The relative pentose phosphate pathway (PPP) flux successively increased, clearly corresponding to the product yield. Moreover, the anaplerotic net flux increased almost twofold as a consequence of concerted regulation of C(3) carboxylation and C(4) decarboxylation fluxes to cover the increased demand for lysine formation; thus, the overall increase was a consequence of concerted regulation of C(3) carboxylation and C(4) decarboxylation fluxes. The relative flux through isocitrate dehydrogenase dropped from 82.7% in the wild type to 59.9% in the lysine-producing mutants. In contrast to the NADPH demand, which increased from 109 to 172% due to the increasing lysine yield, the overall NADPH supply remained constant between 185 and 196%, resulting in a decrease in the apparent NADPH excess through strain optimization. Extrapolated to industrial lysine producers, the NADPH supply might become a limiting factor. The relative contributions of PPP and the tricarboxylic acid cycle to NADPH generation changed markedly, indicating that C. glutamicum is able to maintain a constant supply of NADPH under completely different flux conditions. Statistical analysis by a Monte Carlo approach revealed high precision for the estimated fluxes, underlining the

New fermentation processes for producing itaconic acid and citric acid for industrial uses

Science.gov (United States)

Itaconic acid is an important industrial chemical that we have produced by fermentation of simple sugars using the yeast Pseudozyma antarctica. Itaconic acid is priced at ~$4 per kg and has an annual market volume of about 15,000 metric tons. Itaconic acid is used in the polymer industry and for m...

Bacillus spp. produce antibacterial activities against lactic acid bacteria that contaminate fuel ethanol plants.

Science.gov (United States)

Manitchotpisit, Pennapa; Bischoff, Kenneth M; Price, Neil P J; Leathers, Timothy D

2013-05-01

Lactic acid bacteria (LAB) frequently contaminate commercial fuel ethanol fermentations, reducing yields and decreasing profitability of biofuel production. Microorganisms from environmental sources in different geographic regions of Thailand were tested for antibacterial activity against LAB. Four bacterial strains, designated as ALT3A, ALT3B, ALT17, and MR1, produced inhibitory effects on growth of LAB. Sequencing of rRNA identified these strains as species of Bacillus subtilis (ALT3A and ALT3B) and B. cereus (ALT17 and MR1). Cell mass from colonies and agar samples from inhibition zones were analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The spectra of ALT3A and ALT3B showed a strong signal at m/z 1,060, similar in mass to the surfactin family of antimicrobial lipopeptides. ALT3A and ALT3B were analyzed by zymogram analysis using SDS-PAGE gels placed on agar plates inoculated with LAB. Cell lysates possessed an inhibitory protein of less than 10 kDa, consistent with the production of an antibacterial lipopeptide. Mass spectra of ALT17 and MR1 had notable signals at m/z 908 and 930 in the whole cell extracts and at m/z 687 in agar, but these masses do not correlate with those of previously reported antibacterial lipopeptides, and no antibacterial activity was detected by zymogram. The antibacterial activities produced by these strains may have application in the fuel ethanol industry as an alternative to antibiotics for prevention and control of bacterial contamination.

Metabolic engineering of a haploid strain derived from a triploid industrial yeast for producing cellulosic ethanol.

Science.gov (United States)

Kim, Soo Rin; Skerker, Jeffrey M; Kong, In Iok; Kim, Heejin; Maurer, Matthew J; Zhang, Guo-Chang; Peng, Dairong; Wei, Na; Arkin, Adam P; Jin, Yong-Su

2017-03-01

Many desired phenotypes for producing cellulosic biofuels are often observed in industrial Saccharomyces cerevisiae strains. However, many industrial yeast strains are polyploid and have low spore viability, making it difficult to use these strains for metabolic engineering applications. We selected the polyploid industrial strain S. cerevisiae ATCC 4124 exhibiting rapid glucose fermentation capability, high ethanol productivity, strong heat and inhibitor tolerance in order to construct an optimal yeast strain for producing cellulosic ethanol. Here, we focused on developing a general approach and high-throughput screening method to isolate stable haploid segregants derived from a polyploid parent, such as triploid ATCC 4124 with a poor spore viability. Specifically, we deleted the HO genes, performed random sporulation, and screened the resulting segregants based on growth rate, mating type, and ploidy. Only one stable haploid derivative (4124-S60) was isolated, while 14 other segregants with a stable mating type were aneuploid. The 4124-S60 strain inherited only a subset of desirable traits present in the parent strain, same as other aneuploids, suggesting that glucose fermentation and specific ethanol productivity are likely to be genetically complex traits and/or they might depend on ploidy. Nonetheless, the 4124-60 strain did inherit the ability to tolerate fermentation inhibitors. When additional genetic perturbations known to improve xylose fermentation were introduced into the 4124-60 strain, the resulting engineered strain (IIK1) was able to ferment a Miscanthus hydrolysate better than a previously engineered laboratory strain (SR8), built by making the same genetic changes. However, the IIK1 strain showed higher glycerol and xylitol yields than the SR8 strain. In order to decrease glycerol and xylitol production, an NADH-dependent acetate reduction pathway was introduced into the IIK1 strain. By consuming 2.4g/L of acetate, the resulting strain (IIK1A

Complete genome sequence of Lactobacillus plantarum LZ95, a potential probiotic strain producing bacteriocins and B-group vitamin riboflavin.

Science.gov (United States)

Li, Ping; Gu, Qing

2016-07-10

Lactobacillus plantarum LZ95 is a potential probiotic isolated from newborn infant fecal and it is identified to produce riboflavin with great antimicrobial activity. The complete genome sequence of this strain was reported in the present study. The genome contains a 3,261,418-bp chromosome and two plasmids. Genes, related to the biosynthesis of bacteriocins and riboflavin, were identified. This work will facilitate to reveal the biosynthetic mechanism of bacteriocins and B-group vitamins in lactic acid bacteria and provide evidence for its potential application in food industry. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of Jerusalem artichoke resource for efficient one-step fermentation of poly-(γ-glutamic acid) using a novel strain Bacillus amyloliquefaciens NX-2S.

Science.gov (United States)

Qiu, Yibin; Sha, Yuanyuan; Zhang, Yatao; Xu, Zongqi; Li, Sha; Lei, Peng; Xu, Zheng; Feng, Xiaohai; Xu, Hong

2017-09-01

This study aimed to develop non-food fermentation for the cost-effective production of poly-(γ-glutamic acid) (γ-PGA) using a novel strain of Bacillus amyloliquefaciens NX-2S. The new isolate assimilated inulin more efficiently than other carbohydrates from Jerusalem artichoke, without hydrolytic treatment. To investigate the effect of inulin on γ-PGA production, the transcript levels of γ-PGA synthetase genes (pgsB, pgsC, pgsA), regulatory genes (comA, degQ, degS), and the glutamic acid biosynthesis gene (glnA) were analyzed; inulin addition upregulated these key genes. Without exogenous glutamate, strain NX-2S could produce 6.85±0.22g/L of γ-PGA during fermentation. Exogenous glutamate greatly enhances the γ-PGA yield (39.4±0.38g/L) and productivity (0.43±0.05g/L/h) in batch fermentation. Our study revealed a potential method of non-food fermentation to produce high-value products. Copyright © 2017. Published by Elsevier Ltd.

Identification of an itaconic acid degrading pathway in itaconic acid producing Aspergillus terreus.

Science.gov (United States)

Chen, Mei; Huang, Xuenian; Zhong, Chengwei; Li, Jianjun; Lu, Xuefeng

2016-09-01

Itaconic acid, one of the most promising and flexible bio-based chemicals, is mainly produced by Aspergillus terreus. Previous studies to improve itaconic acid production in A. terreus through metabolic engineering were mainly focused on its biosynthesis pathway, while the itaconic acid-degrading pathway has largely been ignored. In this study, we used transcriptomic, proteomic, bioinformatic, and in vitro enzymatic analyses to identify three key enzymes, itaconyl-CoA transferase (IctA), itaconyl-CoA hydratase (IchA), and citramalyl-CoA lyase (CclA), that are involved in the catabolic pathway of itaconic acid in A. terreus. In the itaconic acid catabolic pathway in A. terreus, itaconic acid is first converted by IctA into itaconyl-CoA with succinyl-CoA as the CoA donor, and then itaconyl-CoA is hydrated into citramalyl-CoA by IchA. Finally, citramalyl-CoA is cleaved into acetyl-CoA and pyruvate by CclA. Moreover, IctA can also catalyze the reaction between citramalyl-CoA and succinate to generate succinyl-CoA and citramalate. These results, for the first time, identify the three key enzymes, IctA, IchA, and CclA, involved in the itaconic acid degrading pathway in itaconic acid producing A. terreus. The results will facilitate the improvement of itaconic acid production by metabolically engineering the catabolic pathway of itaconic acid in A. terreus.

Importance of the Long-Chain Fatty Acid Beta-Hydroxylating Cytochrome P450 Enzyme YbdT for Lipopeptide Biosynthesis in Bacillus subtilis Strain OKB105

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Michael J. McInerney

2011-03-01

Full Text Available Bacillus species produce extracellular, surface-active lipopeptides such as surfactin that have wide applications in industry and medicine. The steps involved in the synthesis of 3-hydroxyacyl-coenzyme A (CoA substrates needed for surfactin biosynthesis are not understood. Cell-free extracts of Bacillus subtilis strain OKB105 synthesized lipopeptide biosurfactants in presence of L-amino acids, myristic acid, coenzyme A, ATP, and H2O2, which suggested that 3-hydroxylation occurs prior to CoA ligation of the long chain fatty acids (LCFAs. We hypothesized that YbdT, a cytochrome P450 enzyme known to beta-hydroxylate LCFAs, functions to form 3-hydroxy fatty acids for lipopeptide biosynthesis. An in-frame mutation of ybdT was constructed and the resulting mutant strain (NHY1 produced predominantly non-hydroxylated lipopeptide with diminished biosurfactant and beta-hemolytic activities. Mass spectrometry showed that 95.6% of the fatty acids in the NHY1 biosurfactant were non-hydroxylated compared to only ~61% in the OKB105 biosurfactant. Cell-free extracts of the NHY1 synthesized surfactin containing 3-hydroxymyristic acid from 3-hydroxymyristoyl-CoA at a specific activity similar to that of the wild type (17 ± 2 versus 17.4 ± 6 ng biosurfactant min−1·ng·protein−1, respectively. These results showed that the mutation did not affect any function needed to synthesize surfactin once the 3-hydroxyacyl-CoA substrate was formed and that YbdT functions to supply 3-hydroxy fatty acid for surfactin biosynthesis. The fact that YbdT is a peroxidase could explain why biosurfactant production is rarely observed in anaerobically grown Bacillus species. Manipulation of LCFA specificity of YbdT could provide a new route to produce biosurfactants with activities tailored to specific functions.

Screening and Evaluation of Polyhydroxybutyrate-Producing Strains from Indigenous Isolate Cupriavidus taiwanensis Strains

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Om-Murugan Janarthanan

2011-01-01

Full Text Available Polyhydroxyalkanoate (PHA is a biodegradable material with many potential biomedical applications, including medical implants and drug delivery. This study developed a system for screening production strains in order to optimize PHA production in Cupriavidus taiwanensis 184, 185, 186, 187, 204, 208, 209 and Pseudomona oleovorans ATCC 29347. In this study, Sudan black B staining, Infrared (IR and Gas Chromatography (GC analysis indicated that the best strain for PHA synthesis is C. taiwanensis 184, which obtains polyhydroxybutyrate (PHB. Cultivation of C. taiwanensis 184 under a pH of 7.0, at 30 °C, and at an agitation rate of 200 rpm, obtained a PHB content of 10% and PHB production of 0.14 g/L. The carbon and nitrogen types selected for analysis of PHB production by C. taiwanensis 184 were gluconic acid and NH4Cl, respectively. Optimal carbon/nitrogen ratio for PHB production was also determined. This study demonstrated a PHB content of 58.81% and a PHB production of 2.44 g/L when the carbon/nitrogen ratio of 8/1 was selected for C. taiwanensis 184. A two‑stage fermentation strategy significantly enhanced PHB content and PHB production. Under a two-stage fermentation strategy with nutrient‑limited conditions, C. taiwanensis 184 obtained a PHB content of 72% and a PHB concentration of 7 g/L. Finally, experimental results confirmed that optimizing the growth medium and fermentation conditions for cultivating the indigenous C. taiwanensis 184 strain substantially elevated PHB content from 10% to 72% and PHB production from 0.14 g/L to 7 g/L, respectively.

Preliminary characterization of wild lactic acid bacteria and their abilities to produce flavour compounds in ripened model cheese system.

Science.gov (United States)

Randazzo, C L; De Luca, S; Todaro, A; Restuccia, C; Lanza, C M; Spagna, G; Caggia, C

2007-08-01

The aim of this work was to preliminary characterize wild lactic acid bacteria (LAB), previously isolated during artisanal Pecorino Siciliano (PS) cheese-making for technological and flavour formation abilities in a model cheese system. Twelve LAB were studied for the ability to grow at 10 and 45 degrees C, to coagulate and acidify both reconstituted skim milk and ewe's milk. Moreover, the capacity of the strains to generate aroma compounds was evaluated in a model cheese system at 30- and 60-day ripening. Flavour compounds were screened by sensory analysis and throughout gas chromatography (GC)-mass spectrometry (MS). Most of the strains were able to grow both at 10 and 45 degrees C and exhibited high ability to acidify and coagulate ewes' milk. Sensory evaluation revealed that the wild strains produced more significant flavour attributes than commercial strains in the 60-day-old model cheese system. GC-MS data confirmed the results of sensory evaluations and showed the ability of wild lactobacilli to generate key volatile compounds. Particularly, three wild lactobacilli strains, belonging to Lactobacillus casei, Lb. rhamnosus and Lb. plantarum species, generated both in 60- and 30-day-old model cheeses system, the 3-methyl butan(al)(ol) compound, which is associated with fruity taste. The present work preliminarily demonstrated that the technological and flavour formation abilities of the wild strains are strain-specific and that wild lactobacilli, which produced key flavour compounds during ripening, could be used as tailor-made starters. This study reports the technological characterization and flavour formation ability of wild LAB strains isolated from artisanal Pecorino cheese and highlights that the catabolic activities were highly strain dependent. Hence, wild lactobacilli could be selected as tailor-made starter cultures for the PS cheese manufacture.

Survival of Four Probiotic Strains in Acid, Bile Salt and After Spray Drying

OpenAIRE

Rawichar Chaipojjana; Suttipong Phosuksirikul; Arunsri Leejeerajumnean

2014-01-01

The objective of the study was to select the survival of probiotic strains when exposed to acidic and bile salts condition. Four probiotic strains Lactobacillus casei subsp. rhamnosus TISTR 047, Lactobacillus casei TISTR 1500, Lactobacillus acidophilus TISTR 1338 and Lactobacillus plantarum TISTR 1465 were cultured in MRS broth and incubated at 35ºC for 15 hours before being inoculated into acidic condition 5 M HCl, pH 2 for 2 hours and bile salt 0.3%, pH 5.8 for 8 hour. ...

Antimicrobial activity of gallic acid against thermophilic Campylobacter is strain specific and associated with a loss of calcium ions.

Science.gov (United States)

Sarjit, Amreeta; Wang, Yi; Dykes, Gary A

2015-04-01

Gallic acid has been suggested as a potential antimicrobial for the control of Campylobacter but its effectiveness is poorly studied. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of gallic acid against Campylobacter jejuni (n = 8) and Campylobacter coli (n = 4) strains was determined. Gallic acid inhibited the growth of five C. jejuni strains and three C. coli strains (MIC: 15.63-250 μg mL(-1)). Gallic acid was only bactericidal to two C. coli strains (MBC: 125 and 62.5 μg mL(-1)). The mechanism of the bactericidal effect against these two strains (and selected non-susceptible controls) was investigated by determining decimal reduction times and by monitoring the loss of cellular content and calcium ions, and changes in cell morphology. Gallic acid did not result in a loss of cellular content or morphological changes in the susceptible strains as compared to the controls. Gallic acid resulted in a loss of calcium ions (0.58-1.53 μg mL(-1) and 0.54-1.17 μg mL(-1), respectively, over a 180 min period) from the susceptible strains but not the controls. Gallic acid is unlikely to be an effective antimicrobial against Campylobacter in a practical sense unless further interventions to ensure an effective bactericidal mode of action against all strains are developed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Isolation and Selection of Microalgal Strains from Natural Water Sources in Viet Nam with Potential for Edible Oil Production.

Science.gov (United States)

Thao, Tran Yen; Linh, Dinh Thi Nhat; Si, Vo Chi; Carter, Taylor W; Hill, Russell T

2017-06-23

Industrial vegetable oil production in Viet Nam depends on oil seeds and crude plant oils that are currently more than 90% imported. As the first step in investigating the feasibility of using microalgae to provide Viet Nam with a domestic source of oil for food and edible oil industries, fifty lipid-producing microalgae were isolated and characterized. The microalgae were isolated from water sources ranging from freshwater to brackish and marine waters from a wide geographic distribution in Viet Nam. Initial analyses showed that 20 of the 50 strains had good growth rates, produced high biomass and had high lipid content, ranging up to 50% of dry weight biomass. 18S rRNA gene sequence analyses of the 50 strains showed a great diversity in this assemblage of microalgae, comprising at least 38 species and representatives of 25 genera : Chlamydomonas , Poterioochromonas , Scenedesmus , Desmodesmus , Chlorella , Bracteacoccus , Monoraphidium , Selenastrum , Acutodesmus , Mychonastes , Ankistrodesmus , Kirchneriella , Raphidocelis , Dictyosphaerium , Coelastrella , Schizochlamydella , Oocystidium , Nannochloris , Auxenochlorella , Chlorosarcinopsis , Stichococcus , Picochlorum , Prasinoderma , Chlorococcum , and Marvania. Some of the species are closely related to well-known lipid producers such as Chlorella sorokiniana , but some other strains are not closely related to the strains found in public sequence databases and likely represent new species. Analysis of oil quality showed that fatty acid profiles of the microalgal strains were very diverse and strain-dependent. Fatty acids in the microalgal oils comprised saturated fatty acids (SFAs), poly-unsaturated fatty acids (PUFAs), and mono-unsaturated fatty acids (MUFAs). The main SFA was palmitic acid. MUFAs and PUFAs were dominated by oleic acid, and linoleic and linolenic acids, respectively. Some strains were especially rich in the essential fatty acid α-linolenic acid (ALA), which comprised more than 20% of the

Strains of Lactococcus lactis with a partial pyrimidine requirement show sensitivity toward aspartic acid

DEFF Research Database (Denmark)

Wadskov-Hansen, Steen Lyders Lerche; Martinussen, Jan

2009-01-01

The growth rate of the widely used laboratory strain Lactococcus lactis subsp. cremoris LM0230 was reduced if aspartic acid were present in the growth medium. The strain LM0230 is a plasmid- and phage-cured derivative of L. lactis subsp. cremoris C2, the ancestor of the original dairy isolate L...... with the wild-type strain, and this varied with the concentration of aspartic acid. The observed effect of aspartate could be explained by the accumulation of the toxic pyrimidine de novo pathway intermediate, carbamoyl aspartate. Assays of the pyrimidine biosynthetic enzymes of L. lactis LM0230 showed...... that the partial pyrimidine requirement can be explained by a low specific activity of the pyrimidine biosynthetic enzymes. In conclusion, L. lactis LM0230 during the process of plasmid- and prophage-curing has acquired a partial pyrimidine requirement resulting in sensitivity toward aspartic acid....

Antimicrobial Properties of Copper Nanoparticles and Amino Acid Chelated Copper Nanoparticles Produced by Using a Soya Extract

Science.gov (United States)

DeAlba-Montero, I.; Morales-Sánchez, Elpidio; Araujo-Martínez, Rene

2017-01-01

This paper reports a comparison of the antibacterial properties of copper-amino acids chelates and copper nanoparticles against Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis. These copper-amino acids chelates were synthesized by using a soybean aqueous extract and copper nanoparticles were produced using as a starting material the copper-amino acids chelates species. The antibacterial activity of the samples was evaluated by using the standard microdilution method (CLSI M100-S25 January 2015). In the antibacterial activity assays copper ions and copper-EDTA chelates were included as references, so that copper-amino acids chelates can be particularly suitable for acting as an antibacterial agent, so they are excellent candidates for specific applications. Additionally, to confirm the antimicrobial mechanism on bacterial cells, MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) was carried out. A significant enhanced antimicrobial activity and a specific strain were found for copper chelates over E. faecalis. Its results would eventually lead to better utilization of copper-amino acids chelate for specific application where copper nanoparticles can be not used. PMID:28286459

Degradation of 2,4-dichlorophenoxyacetic acid by a halotolerant strain of Penicillium chrysogenum: antibiotic production.

Science.gov (United States)

Ferreira-Guedes, Sumaya; Mendes, Benilde; Leitão, Ana Lúcia

2012-01-01

The extensive use of pesticides in agriculture has prompted intensive research on chemical and biological methods in order to protect contamination of water and soil resources. In this paper the degradation of the pesticide 2,4-dichlorophenoxyacetic acid by a Penicillium chrysogenum strain previously isolated from a salt mine was studied in batch cultures. Co-degradation of 2,4-dichlorophenoxyacetic acid with additives such as sugar and intermediates of pesticide metabolism was also investigated. Penicillium chrysogenum in solid medium was able to grow at concentrations up to 1000 mg/L of 2,4-dichlorophenoxyacetic acid (2,4-D) with sucrose. Meanwhile, supplementation of the solid medium with glucose and lactose led to fungal growth at concentrations up to 500 mg/L of herbicide. Batch cultures of 2,4-D at 100 mg/L were developed under aerobic conditions with the addition of glucose, lactose and sucrose, showing sucrose as the best additional carbon source. The 2,4-D removal was quantified by liquid chromatography. The fungus was able to use 2,4-D as the sole carbon and energy source under 0%, 2% and 5.9% NaCl. The greatest 2,4-D degradation efficiency was found using alpha-ketoglutarate and ascorbic acid as co-substrates under 2% NaCl at pH 7. Penicillin production was evaluated in submerged cultures by bioassay, and higher amounts of beta-lactam antibiotic were produced when the herbicide was alone. Taking into account the ability of P. chrysogenum CLONA2 to degrade aromatic compounds, this strain could be an interesting tool for 2,4-D herbicide remediation in saline environments.

Lactic acid production from xylose by Geobacillus stearothermophilus strain 15

Science.gov (United States)

Kunasundari, B.; Naresh, S.; Chu, J. E.

2017-09-01

Lactic acid is an important compound with a wide range of industrial applications. The present study tested the efficiency of xylose, as a sole carbon source to be converted to lactic acid by Geobacillus stearothermophilus strain 15. To the best of our knowledge, limited information is available on the directed fermentation of xylose to lactic acid by this bacterium. The effects of different parameters such as temperature, pH, incubation time, agitation speed, concentrations of nitrogen and carbon sources on the lactic acid production were investigated statistically. It was found that the bacterium exhibited poor assimilation of xylose to lactic acid. Temperature, agitation rate and incubation time were determined to improve the lactic acid production slightly. The highest lactic acid yield obtained was 8.9% at 45°C, 300 RPM, 96 h, pH of 6.0 with carbon and nitrogen source concentrations were fixed at 5% w/v.

Draft Genome Sequence of the Efficient Bioflocculant-Producing Bacterium Paenibacillus sp. Strain A9

Science.gov (United States)

Liu, Jin-liang; Hu, Xiao-min

2013-01-01

Paenibacillus sp. strain A9 is an important bioflocculant-producing bacterium, isolated from a soil sample, and is pale pink-pigmented, aerobic, and Gram-positive. Here, we report the draft genome sequence and the initial findings from a preliminary analysis of strain A9, which is a novel species of Paenibacillus. PMID:23618713

Indole-3-Acetic Acid-Producing Yeasts in the Phyllosphere of the Carnivorous Plant Drosera indica L

Science.gov (United States)

Shin, Li-Ying; Wei, Jyuan-Yu; Fu, Shih-Feng; Chou, Jui-Yu

2014-01-01

Yeasts are widely distributed in nature and exist in association with other microorganisms as normal inhabitants of soil, vegetation, and aqueous environments. In this study, 12 yeast strains were enriched and isolated from leaf samples of the carnivorous plant Drosera indica L., which is currently threatened because of restricted habitats and use in herbal industries. According to similarities in large subunit and small subunit ribosomal RNA gene sequences, we identified 2 yeast species in 2 genera of the phylum Ascomycota, and 5 yeast species in 5 genera of the phylum Basidiomycota. All of the isolated yeasts produced indole-3-acetic acid (IAA) when cultivated in YPD broth supplemented with 0.1% L-tryptophan. Growth conditions, such as the pH and temperature of the medium, influenced yeast IAA production. Our results also suggested the existence of a tryptophan-independent IAA biosynthetic pathway. We evaluated the effects of various concentrations of exogenous IAA on yeast growth and observed that IAA produced by wild yeasts modifies auxin-inducible gene expression in Arabidopsis. Our data suggest that yeasts can promote plant growth and support ongoing prospecting of yeast strains for inclusion into biofertilizer for sustainable agriculture. PMID:25464336

Inhibitory effect of bacteriocin-producing lactic acid bacteria against histamine-forming bacteria isolated from Myeolchi-jeot

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Eun-Seo Lim

2016-12-01

Full Text Available Abstract The objectives of this study were to identify the histamine-forming bacteria and bacteriocin- producing lactic acid bacteria (LAB isolated from Myeolchi-jeot according to sequence analysis of the 16S rRNA gene, to evaluate the inhibitory effects of the bacteriocin on the growth and histamine accumulation of histamine-forming bacteria, and to assess the physico-chemical properties of the bacteriocin. Based on 16S rRNA gene sequences, histamine-forming bacteria were identified as Bacillus licheniformis MCH01, Serratia marcescens MCH02, Staphylococcus xylosus MCH03, Aeromonas hydrophila MCH04, and Morganella morganii MCH05. The five LAB strains identified as Pediococcus acidilactici MCL11, Leuconostoc mesenteroides MCL12, Enterococcus faecium MCL13, Lactobacillus sakei MCL14, and Lactobacillus acidophilus MCL15 were found to produce an antibacterial compound with inhibitory activity against the tested histamine-producing bacteria. The inhibitory activity of these bacteriocins obtained from the five LAB remained stable after incubation at pH 4.0–8.0 and heating for 10 min at 80 °C; however, the bacteriocin activity was destroyed after treatment with papain, pepsin, proteinase K, α-chymotrypsin, or trypsin. Meanwhile, these bacteriocins produced by the tested LAB strains also exhibited histamine-degradation ability. Therefore, these antimicrobial substances may play a role in inhibiting histamine formation in the fermented fish products and preventing seafood-related food-borne disease caused by bacterially generated histamine.

Adaptive laboratory evolution of ethanologenic Zymomonas mobilis strain tolerant to furfural and acetic acid inhibitors.

Science.gov (United States)

Shui, Zong-Xia; Qin, Han; Wu, Bo; Ruan, Zhi-yong; Wang, Lu-shang; Tan, Fu-Rong; Wang, Jing-Li; Tang, Xiao-Yu; Dai, Li-Chun; Hu, Guo-Quan; He, Ming-Xiong

2015-07-01

Furfural and acetic acid from lignocellulosic hydrolysates are the prevalent inhibitors to Zymomonas mobilis during cellulosic ethanol production. Developing a strain tolerant to furfural or acetic acid inhibitors is difficul by using rational engineering strategies due to poor understanding of their underlying molecular mechanisms. In this study, strategy of adaptive laboratory evolution (ALE) was used for development of a furfural and acetic acid-tolerant strain. After three round evolution, four evolved mutants (ZMA7-2, ZMA7-3, ZMF3-2, and ZMF3-3) that showed higher growth capacity were successfully obtained via ALE method. Based on the results of profiling of cell growth, glucose utilization, ethanol yield, and activity of key enzymes, two desired strains, ZMA7-2 and ZMF3-3, were achieved, which showed higher tolerance under 7 g/l acetic acid and 3 g/l furfural stress condition. Especially, it is the first report of Z. mobilis strain that could tolerate higher furfural. The best strain, Z. mobilis ZMF3-3, has showed 94.84% theoretical ethanol yield under 3-g/l furfural stress condition, and the theoretical ethanol yield of ZM4 is only 9.89%. Our study also demonstrated that ALE method might also be used as a powerful metabolic engineering tool for metabolic engineering in Z. mobilis. Furthermore, the two best strains could be used as novel host for further metabolic engineering in cellulosic ethanol or future biorefinery. Importantly, the two strains may also be used as novel-tolerant model organisms for the genetic mechanism on the "omics" level, which will provide some useful information for inverse metabolic engineering.

Assessing the potential of fatty acids produced by filamentous fungi as feedstock for biodiesel production.

Science.gov (United States)

Rivaldi, Juan Daniel; Carvalho, Ana Karine F; da Conceição, Leyvison Rafael V; de Castro, Heizir F

2017-11-26

Increased costs and limited availability of traditional lipid sources for biodiesel production encourage researchers to find more sustainable feedstock at low prices. Microbial lipid stands out as feedstock replacement for vegetable oil to convert fatty acid esters. In this study, the potential of three isolates of filamentous fungi (Mucor circinelloides URM 4140, M. hiemalis URM 4144, and Penicillium citrinum URM 4126) has been assessed as single-cell oil (SCO) producers. M. circinelloides 4140 had the highest biomass concentration with lipid accumulation of up to 28 wt% at 120 hr of cultivation. The profile of fatty acids revealed a high content of saturated (SFA) and monounsaturated fatty acids (MUFA), including palmitic (C16:0, 33.2-44.1 wt%) and oleic (C18:1, 20.7-31.2 wt%) acids, with the absence of polyunsaturated fatty acids (PUFA) having more than four double bonds. Furthermore, the predicted properties of biodiesel generated from synthesized SCOs have been estimated by using empirical models which were in accordance with the limits imposed by the USA (ASTM D6715), European Union (EN 14214), and Brazilian (ANP 45/2014) standards. These results suggest that the assessed filamentous fungus strains can be considered as alternative feedstock sources for high-quality biofuel production.

Clonality and Resistome analysis of KPC-producing Klebsiella pneumoniae strain isolated in Korea using whole genome sequencing.

Science.gov (United States)

Lee, Yangsoon; Kim, Bong-Soo; Chun, Jongsik; Yong, Ji Hyun; Lee, Yeong Seon; Yoo, Jung Sik; Yong, Dongeun; Hong, Seong Geun; D'Souza, Roshan; Thomson, Kenneth S; Lee, Kyungwon; Chong, Yunsop

2014-01-01

We analyzed the whole genome sequence and resistome of the outbreak Klebsiella pneumoniae strain MP14 and compared it with those of K. pneumoniae carbapenemase- (KPC-) producing isolates that showed high similarity in the NCBI genome database. A KPC-2-producing multidrug-resistant (MDR) K. pneumoniae clinical isolate was obtained from a patient admitted to a Korean hospital in 2011. The strain MP14 was resistant to all tested β-lactams including monobactam, amikacin, levofloxacin, and cotrimoxazole, but susceptible to tigecycline and colistin. Resistome analysis showed the presence of β-lactamase genes including bla KPC-2, bla SHV-11, bla TEM-169, and bla OXA-9. MP14 also possessed aac(6'-)Ib, aadA2, and aph(3'-)Ia as aminoglycoside resistance-encoding genes, mph(A) for macrolides, oqxA and oqxB for quinolone, catA1 for phenicol, sul1 for sulfonamide, and dfrA12 for trimethoprim. Both SNP tree and cgMLST analysis showed the close relatedness with the KPC producers (KPNIH strains) isolated from an outbreak in the USA and colistin-resistant strains isolated in Italy. The plasmid-scaffold genes in plasmids pKpQil, pKpQil-IT, pKPN3, or pKPN-IT were identified in MP14, KPNIH, and Italian strains. The KPC-2-producing MDR K. pneumoniae ST258 stain isolated in Korea was highly clonally related with MDR K. pneumoniae strains from the USA and Italy. Global spread of KPC-producing K. pneumoniae is a worrying phenomenon.

Clonality and Resistome Analysis of KPC-Producing Klebsiella pneumoniae Strain Isolated in Korea Using Whole Genome Sequencing

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Yangsoon Lee

2014-01-01

Full Text Available We analyzed the whole genome sequence and resistome of the outbreak Klebsiella pneumoniae strain MP14 and compared it with those of K. pneumoniae carbapenemase- (KPC- producing isolates that showed high similarity in the NCBI genome database. A KPC-2-producing multidrug-resistant (MDR K. pneumoniae clinical isolate was obtained from a patient admitted to a Korean hospital in 2011. The strain MP14 was resistant to all tested β-lactams including monobactam, amikacin, levofloxacin, and cotrimoxazole, but susceptible to tigecycline and colistin. Resistome analysis showed the presence of β-lactamase genes including blaKPC-2, blaSHV-11, blaTEM-169, and blaOXA-9. MP14 also possessed aac(6′-Ib, aadA2, and aph(3′-Ia as aminoglycoside resistance-encoding genes, mph(A for macrolides, oqxA and oqxB for quinolone, catA1 for phenicol, sul1 for sulfonamide, and dfrA12 for trimethoprim. Both SNP tree and cgMLST analysis showed the close relatedness with the KPC producers (KPNIH strains isolated from an outbreak in the USA and colistin-resistant strains isolated in Italy. The plasmid-scaffold genes in plasmids pKpQil, pKpQil-IT, pKPN3, or pKPN-IT were identified in MP14, KPNIH, and Italian strains. The KPC-2-producing MDR K. pneumoniae ST258 stain isolated in Korea was highly clonally related with MDR K. pneumoniae strains from the USA and Italy. Global spread of KPC-producing K. pneumoniae is a worrying phenomenon.

Effect of riboflavin-producing bacteria against chemically induced colitis in mice.

Science.gov (United States)

Levit, R; Savoy de Giori, G; de Moreno de LeBlanc, A; LeBlanc, J G

2018-01-01

To assess the anti-inflammatory effect associated with individual probiotic suspensions of riboflavin-producing lactic acid bacteria (LAB) in a colitis murine model. Mice intrarectally inoculated with trinitrobenzene sulfonic acid (TNBS) were orally administered with individual suspensions of riboflavin-producing strains: Lactobacillus (Lact.) plantarum CRL2130, Lact. paracasei CRL76, Lact. bulgaricus CRL871 and Streptococcus thermophilus CRL803; and a nonriboflavin-producing strain or commercial riboflavin. The extent of colonic damage and inflammation and microbial translocation to liver were evaluated. iNOs enzyme was analysed in the intestinal tissues and cytokine concentrations in the intestinal fluids. Animals given either one of the four riboflavin-producing strains showed lower macroscopic and histologic damage scores, lower microbial translocation to liver, significant decreases of iNOs+ cells in their large intestines and decreased proinflammatory cytokines, compared with mice without treatment. The administration of pure riboflavin showed similar benefits. Lact. paracasei CRL76 accompanied its anti-inflammatory effect with increased IL-10 levels demonstrating other beneficial properties in addition to the vitamin production. Administration of riboflavin-producing strains prevented the intestinal damage induced by TNBS in mice. Riboflavin-producing phenotype in LAB represents a potent tool to select them for preventing/treating IBD. © 2017 The Society for Applied Microbiology.

Bioconversion of ferulic acid to vanillin by combined action of ...

African Journals Online (AJOL)

Ability of 10 fungi strains for the degradation of ferulic acid and production of vanillic acid was examined. The findings suggested that all the fungi were able to degrade ferulic acid via different pathways producing variety of products. Vanillic acid was the main bioconversion product for all the fungi strains. Aspergillus niger ...

Detection and transmission of extracellular fac-tor producing Streptococcus suis serotype 2 strains in pigs

NARCIS (Netherlands)

Swildens, B.

2009-01-01

DETECTION AND TRANSMISSION OF EXTRACELLULAR FACTOR PRODUCING STREPTOCOCCUS SUIS SEROTYPE 2 STRAINS IN PIGS INTRODUCTION Streptococcus suis (S.suis) has been implicated in the etiology of many diseases among which meningitis in pigs. The virulent extracellular factor-positive strains of S.suis

Mutant breeding of Aspergillus niger irradiated by 12C6+ for hyper citric acid

International Nuclear Information System (INIS)

Hu Wei; Li Wenjian; Chen Jihong; Liu Jing; Wang Shuyang; Wang Jufang; Lu Dong

2014-01-01

In this study, strains of Aspergillus niger No.4 for hyper citric acid were irradiated to different doses by 80 MeV/u 12 C 6+ ion beams. Seven mutant strains showed marked citric acid over-production records and faster productivity than initial Aspergillus niger No.4 by shaking flash fermentation. The maximum product yield was 132.8 gL -1 (the H4002 strain) being a 8.8% increase to the initial strain. The scale-up experiment was carried out in a 100 L bioreactor. The mutant H4002 can accumulate 187gL -1 product yield of citric acid from starch liquefying supernatant. The productivity of citric acid was 2.75 g L -1 h -1 . So, the mutant H4002 possesses rapid sugar katabolism for producing citric acid. Meanwhile, the pellet morphology kept compact and round during the whole submerged fermentation, which was suited to produce citric acid. The results indicate that mutant H4002 has potential ability to produce citric acid rapidly. (authors)

Genomic analysis of thermophilic Bacillus coagulans strains: efficient producers for platform bio-chemicals.

Science.gov (United States)

Su, Fei; Xu, Ping

2014-01-29

Microbial strains with high substrate efficiency and excellent environmental tolerance are urgently needed for the production of platform bio-chemicals. Bacillus coagulans has these merits; however, little genetic information is available about this species. Here, we determined the genome sequences of five B. coagulans strains, and used a comparative genomic approach to reconstruct the central carbon metabolism of this species to explain their fermentation features. A novel xylose isomerase in the xylose utilization pathway was identified in these strains. Based on a genome-wide positive selection scan, the selection pressure on amino acid metabolism may have played a significant role in the thermal adaptation. We also researched the immune systems of B. coagulans strains, which provide them with acquired resistance to phages and mobile genetic elements. Our genomic analysis provides comprehensive insights into the genetic characteristics of B. coagulans and paves the way for improving and extending the uses of this species.

Conjugated Linoleic Acid Production by Bifidobacteria: Screening, Kinetic, and Composition

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Stefano Raimondi

2016-01-01

Full Text Available Conjugated linoleic acids (CLA are positional and geometric isomers of linoleic acid involved in a number of health aspects. In humans, CLA production is performed by gut microbiota, including some species of potential probiotic bifidobacteria. 128 strains of 31 Bifidobacterium species were screened with a spectrophotometric assay to identify novel CLA producers. Most species were nonproducers, while producers belonged to B. breve and B. pseudocatenulatum. GC-MS revealed that CLA producer strains yielded 9cis,11trans-CLA and 9trans,11trans-CLA, without any production of other isomers. Hydroxylated forms of LA were absent in producer strains, suggesting that the myosin-cross-reactive antigen (MCRA protein that exerts hydratase activity is not involved in LA isomerization. Moreover, both CLA producer and nonproducer species bear a MCRA homologue. The strain B. breve WC 0421 was the best CLA producer, converting LA into 68.8% 9cis,11trans-CLA and 25.1% 9trans,11trans-CLA. Production occurred mostly during the lag and the exponential phase. For the first time, production and incorporation of CLA in biomass were assessed. B. breve WC 0421 stored CLA in the form of free fatty acids, without changing the composition of the esterified fatty acids, which mainly occurred in the plasmatic membrane.

Use of octaketide synthases to produce kermesic acid and flavokermesic acid

DEFF Research Database (Denmark)

2017-01-01

A method for producing an octaketide derived aromatic compound of interest (e.g. carminic acid), wherein the method comprises (I): heterologous expression of a recombinantly introduced Type III polyketide synthase (PKS) gene encoding an octaketide synthase (OKS) to obtain non-reduced octaketide...... in vivo within the recombinant host cell and (II): converting in vivo the non-reduced octaketide of step (I) into a C14-C34 aromatic compound of interest (e.g. carminic acid)....

Use of octaketide synthases to produce kermesic acid and flavokermesic acid

DEFF Research Database (Denmark)

2016-01-01

A method for producing an octaketide derived aromatic compound of interest (e.g. carminic acid), wherein the method comprises (I): heterologous expression of a recombinantly introduced Type III polyketide synthase (PKS) gene encoding an octaketide synthase (OKS) to obtain non-reduced octaketide...... in vivo within the recombinant host cell and (II): converting in vivo the non-reduced octaketide of step (I) into a C14-C34 aromatic compound of interest (e.g. carminic acid)....

Indole-3-acetic acid biosynthesis in Fusarium delphinoides strain GPK, a causal agent of Wilt in Chickpea.

Science.gov (United States)

Kulkarni, Guruprasad B; Sanjeevkumar, S; Kirankumar, B; Santoshkumar, M; Karegoudar, T B

2013-02-01

Fusarium delphinoides (Ascomycota; Nectriaceae) is an indole-3-acetic acid (IAA) producing plant pathogen and a causal agent of wilt in chickpea. The IAA biosynthetic pathway in F. delphinoides strain GPK (FDG) was examined by analyzing metabolic intermediates and by feeding experiments. Gas chromatograph (GC) analysis of FDG culture filtrates showed the presence of metabolic intermediates of indole-3-pyruvic acid (IPyA), indole-3-acetamide (IAM), and tryptamine (TRA) pathways. The different IAA biosynthetic pathways were further confirmed by identifying the presence of different enzymes of these pathways. Substrate specificity study of aromatic amino acid aminotransferase revealed that the enzyme is highly specific for tryptophan (Trp) and α-ketoglutarate (α-kg) as amino group donor and acceptor, respectively. Furthermore, the concentration-dependent effect of exogenous IAA on fungal growth was established. Low concentration of exogenous IAA increases the fungal growth and at high concentration it decreases the growth of FDG.

Evaluation of different lactic acid bacterial strains for probiotic characteristics

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B. Srinu,

2013-08-01

Full Text Available Objective: The objective of the present study was to collect different Lactic acid bacterial strains from culture collection centers and screen their functional probiotic characteristics such as acid tolerance, bile tolerance, antibacterial activity and antibiotic sensitivity for their commercial use. Materials and Methods: Acid and bile tolerence of selected LAB(Lactic acid bacteria was determined. The antibiotic resistance of Lactobacillus species was assessed using different antibiotic discs on de Mann Rogosa Sharpe broth (MRS agar plates seeded with the test probiotic organism. The antibacterial activity of LAB was assessed by using well diffusion method.Results: Among the six probiotic strains tested, all showed good survivability at high bile salt concentration (0.3 to 2.0 % oxgall and good growth at a low pH of 1.5 to 3.5. These probiotic species showed good survival abilities in acidic pH of 2.0 to 3.5 except Lactobacillus delbrueckii subspp. bulgaricus 281 which did not grown at pH of 2.0. Lactobacillus fermentum 141 was able to grow even at pH of 1.5 also. Among the six lactic acid species, Lactobacillus fermentum 141 (except Tetracycline, Lactobacillus delbrueckii subspp. Bulgaricus 281 except (Cefpodoxime and all other LAB were resistant to all the antibiotics tested (Ampicillin, Nalidixic acid , Ciprofloxacin ,Co-Trimoxazole, Gentamicin and Cefpodoxime. All these probiotic organisms were screened for their in vitro inhibition ability against pathogenic microorganisms namely, E.coli ATCC (American type culture collection centre, Pseudomonas aeruginosa, Salmonella paratyphi, Staphylococcus aureus. Lactobacillus delbrueckii subspp. bulgaricus 281, Lactobacillus casei 297 and Lactobacillus fermentum 141 inhibited the growth of all the pathogenic bacteria used in the study. Conclusion: The study indicated Lactobacillus fermentum 141 and Lactobacillus casei 297 as potential functional probiotics for future in vivo studies for

Lactobacillus plantarum CIDCA 8327: An α-glucan producing-strain isolated from kefir grains.

Science.gov (United States)

Gangoiti, M V; Puertas, A I; Hamet, M F; Peruzzo, P J; Llamas, M G; Medrano, M; Prieto, A; Dueñas, M T; Abraham, A G

2017-08-15

Lactobacillus plantarum CIDCA 8327 is an exopolysaccharide (EPS)-producer strain isolated from kefir with promising properties for the development of functional foods. The aim of the present study was to characterize the structure of the EPS synthesized by this strain grown in skim milk or semidefined medium (SDM). Additionally, genes involved in EPS synthesis were detected by PCR. L. plantarum produces an EPS with a molecular weight of 10 4 Da in both media. When grown in SDM produce an heteropolysaccharide composed mainly of glucose, glucosamine and rhamnose meanwhile the EPS produced in milk was composed exclusively of glucose indicating the influence of the sugar source. FTIR spectra of this EPS showed signals attributable to an α-glucan. Both by 1 H NMR and methylation analysis it was possible to determine that this polysaccharide is a branched α-(1→4)-d-glucan composed of 80% linear α-(1→4)-d-glucopyranosyl units and 19% (1→4)-d-glucopyranosyl units substituted at O-3 by single α-d-glucopyranosil residues. Copyright © 2017 Elsevier Ltd. All rights reserved.

Polyamic Acid Nanofibers Produced by Needleless Electro spinning

International Nuclear Information System (INIS)

Jirsak, O.; Sanetrnik, F.; Hruza, J.; Chaloupek, J.; Sysel, P.

2010-01-01

The polyimide precursor (polyamic acid) produced of 4,4'-oxydiphthalic anhydride and 4,4'-oxydianiline was electrospun using needleless electrospinning method. Nonwoven layers consisting of submicron fibers with diameters in the range about 143-470 nm on the polypropylene spunbond supporting web were produced. Filtration properties of these nanofiber layers on the highly permeable polypropylene support namely filtration effectivity and pressure drop were evaluated. Consequently, these polyamic acid fibers were heated to receive polyimide nanofibers. The imidization process has been studied using IR spectroscopy. Some comparisons with the chemically identical polyimide prepared as the film were made.

Purification and characterization of hyaluronic acid produced by Streptococcus zooepidemicus strain 3523-7

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K. Jagadeeswara Reddy

2013-01-01

Full Text Available Hyaluronic acid (HA is a hydrated gel and comprises repeating units of glucuronic acid and N-acetylglucosamine. Production and recovery of HA has gained great importance due to its vast clinical applications. In pursuit of obtaining highly pure HA, we have developed a fed-batch fermentation process using Streptococcus zooepidemicus in a 25 L bioreactor that resulted in a maximum yield of 2.3 g/L HA. In addition, we have devised an efficient method for separation and recovery of hyaluronic acid from a highly viscous broth by treating with trichloroacetic acid (0.1% and charcoal (1-2%, passing through filtration (0.45 μm and ultrafiltration that resulted in recovery of 72.2% of clinical grade HA with molecular weight of 2.5×106 Da. We have also characterized our purified HA using FTIR and NMR spectroscopy. These studies revealed the similarity in both the FTIR spectrum as well as NMR spectrum of both reference standard and purified HA from S. zooepidemicus indicating that the reported process is more efficient in terms of better yield and high quality (99.2%.

Pediocin PA-1 and a pediocin producing Lactobacillus plantarum strain do not change the HMA rat microbiota

DEFF Research Database (Denmark)

Bernbom, Nete; Jelle, N.B.; Brogren, C.-H.

2009-01-01

microbiota was in all treatments dominated by lactic acid bacteria and coliforms and no changes in the rat commensal microbiota were detected after ingestion of either of the two L plantarum strains as determined by both culturable methods and molecular methods (DGGE). Both strains were detected...

Esterase activities of intracellular extracts of wild strains of lactic acid bacteria isolated from Serra da Estrela cheese

OpenAIRE

Macedo, Angela C.; Tavares, Tânia G.; Malcata, F. Xavier

2003-01-01

Lactococcus lactis subsp. lactis strain ESB110019 and Lactobacillus plantarum strain ESB5004, novel strains that were previously isolated from the wild adventitious microflora of certified Serra da Estrela cheeses, were assayed for esterase activity using, as substrates, ortho- and para-nitrophenyl derivatives of fatty acids. Both strains preferentially hydrolyzed short-chain fatty acids; L. lactis ESB110019 exhibited a stronger esterase activity than Lb. plantarum ESB5004 and cleaved the p-n...

Characterization of rhizobacteria associated to maize crop in IAA, siderophores and salicylic acid metabolite production

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Annia Hernández

2004-01-01

Full Text Available It has been demonstrated that rhizobacteria are able to produce metabolites having agricultural interest, including salicylic acid, the siderophores and phytohormones. Indol acetic acid (IAA is the most well-known and studied auxin, playing a governing role in culture growth. The object of this work was to characterise rhizobacteria associated with the maize crop in terms of producing IAA, siderophores and salicylic acid metabolites. Burkholderia cepacia and Pseudomonas fluorescens strains previously isolated from maize Francisco variety rhizosphere were used. Colorimetric and chromatographic techniques for detecting these metabolites were studied; multi-variable analysis of hierarchic conglomerate and complete ligament were used for selecting the best strains for producing metabolites of interest. These results demonstrated that all rhizobacteria strains studied produced IAA, siderophores and salicylic acid metabolites. Burkholderia cepacia MBf21, MBp1, MBp2, MBf22, MBp3, MBf20, MBf 15 and Pseudomonas fluorescens MPp4strains have presented the greatest production of these metabolites, showing that these strains could be used in promoting vegetal growth in economically important cultures. Key words: Pseudomonas fluorescens, Burkholderia cepacia, IAA, siderophore, salicylic acid.

Topochemical approach to efficiently produce main-chain poly(bile acid)s with high molecular weights.

Science.gov (United States)

Li, Weina; Li, Xuesong; Zhu, Wei; Li, Changxu; Xu, Dan; Ju, Yong; Li, Guangtao

2011-07-21

Based on a topochemical approach, a strategy for efficiently producing main-chain poly(bile acid)s in the solid state was developed. This strategy allows for facile and scalable synthesis of main-chain poly(bile acid)s not only with high molecular weights, but also with quantitative conversions and yields.

Effect of acclimation medium on cell viability, membrane integrity and ability to consume malic acid in synthetic wine by oenological Lactobacillus plantarum strains.

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Bravo-Ferrada, B M; Tymczyszyn, E E; Gómez-Zavaglia, A; Semorile, L

2014-02-01

The aim of this work was to evaluate the effect of acclimation on the viability, membrane integrity and the ability to consume malic acid of three oenological strains of Lactobacillus plantarum. Cultures in the stationary phase were inoculated in an acclimation medium (Accl.) containing 0, 6 or 10% v/v ethanol and incubated 48 h at 28°C. After incubation, cells were harvested by centrifugation and inoculated in a synthetic wine, containing 14% v/v ethanol and pH 3.5 at 28°C. Viability and membrane integrity were determined by flow cytometry (FC) using carboxyfluorescein diacetate (cFDA) and propidium iodide. Bacterial growth and malic acid consumption were monitored in a synthetic wine during 15 days. In nonacclimated strains, the damage of bacterial membranes produced a dramatic decrease in microbial viability in synthetic wine. In contrast, survival of strains previously acclimated in Accl. with 6 and 10% v/v ethanol was noticeable higher. Therefore, acclimation with ethanol increased the cultivability in synthetic wine and consequently, the consumption of l-malic acid after 15 days of growth. Acclimation of oenological strains in media containing ethanol prior to wine inoculation significantly decreases the membrane damage and improves viability in the harsh wine conditions. The role of membrane integrity is crucial to warrant the degradation of l-malic acid. The efficiency of multiparametric FC in monitoring viability and membrane damage along with the malic acid consumption has a strong impact on winemaking because it represents a useful tool for a quick and highly reliable evaluation of oenological parameters. © 2013 The Society for Applied Microbiology.

Exopolysaccharide-forming Weissella strains as starter cultures for sorghum and wheat sourdoughs.

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Galle, Sandra; Schwab, Clarissa; Arendt, Elke; Gänzle, Michael

2010-05-12

The addition of sourdough fermented with lactic acid bacteria synthesizing organic acids and oligo- and exopolysaccharides (EPS) from sucrose enhances texture, nutritional value, shelf life, and machinability of wheat, rye, and gluten-free bread. This study compared acetate, mannitol, and oligosaccharide formation of EPS-producing strains of Weissella and Leuconostoc spp. to the traditional sourdough starter Lactobacillus sanfranciscensis. In broth, Leuconostoc strains generally formed acetate and mannitol, whereas Weissella produced only small amounts of acetate and no mannitol in the presence of sucrose. In the presence of sucrose and maltose, Weissella and Leuconostoc strains synthesized glucooligosaccharides and EPS. Strains of Weissella were employed as starter cultures for wheat and sorghum sourdough and formed 0.8-8 g kg(-1) EPS and gluco-oligosaccharides but only low amounts of acetate and mannitol. In contrast, the formation of EPS from sucrose led to the production of high amounts of acetate and mannitol by L. sanfranciscensis LTH 2950 in wheat sourdough. This study indicates that Weissella strains are suitable starter cultures for wheat and sorghum sourdoughs and efficiently produce gluco-oligosaccharides and EPS.

The prevalence of ESBL-producing E-coli and Klebsiella strains in the Copenhagen area of Denmark

DEFF Research Database (Denmark)

Kjerulf, A.; Hansen, D.S.; Sandvang, D.

2008-01-01

The main purpose of the study was to investigate the frequency of ESBL-producing E. coli and Klebsiella strains in the Greater Copenhagen area. Four collections of strains were investigated: A) 380 consecutive E. coli and Klebsiella isolates primarily from urine, B) 200 gentamicin-resistant E. coli...... and Klebsiella isolates primarily from urine, C) 210 consecutive E. coli isolates from blood cultures, and D) 68 cefuroxime-resistant E. coli and Klebsiella isolates primarily from urine. Only one strain per patient was included. Strains with a zone diameter for cefpodoxime ...). In conclusion, the frequency of ESBL-producing E. coli and Klebsiella isolates was low in the Copenhagen area of Denmark (0.8 %). The most common ESBL genes found in our study were ctx-m and shv genes Udgivelsesdato: 2008/2...

Screening and kinetics of glutaminase and glutamate decarboxylase producing lactic acid bacteria from fermented Thai foods

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Sasimar Woraharn

2014-12-01

Full Text Available L-glutaminase and glutamic acid decarboxylase (GAD catalyzes the hydrolysis of L-glutamine and glutamate, respectively. L-glutaminase widely used in cancer therapy along with a combination of other enzymes and most importantly these enzymes were used in food industries, as a major catalyst of bioconversion. The current investigation was aimed to screen and select L-glutaminase, and GAD producing lactic acid bacteria (LAB. A total of 338 LAB were isolated from fermented meat, fermented fish, fermented soya bean, fermented vegetables and fruits. Among 338 isolates, 22 and 237 LAB has been found to be positive for L-glutaminase and GAD, respectively. We found that 30 days of incubation at 35 ºC and pH 6.0 was the optimum condition for glutaminase activity by G507/1. G254/2 was found to be the best for GAD activity with the optimum condition of pH 6.5, temperature 40 ºC and ten days of incubation. These LAB strains, G507/1 and G254/2, were identified as close relative of Lactobacillus brevis ATCC 14869 and Lactobacillus fermentum NBRC 3956, respectively by 16S rRNA sequencing. Further, improvements in up-stream of the fermentation process with these LAB strains are currently under development.

Identification, purification and characterization of laterosporulin, a novel bacteriocin produced by Brevibacillus sp. strain GI-9.

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Pradip Kumar Singh

Full Text Available BACKGROUND: Bacteriocins are antimicrobial peptides that are produced by bacteria as a defense mechanism in complex environments. Identification and characterization of novel bacteriocins in novel strains of bacteria is one of the important fields in bacteriology. METHODOLOGY/FINDINGS: The strain GI-9 was identified as Brevibacillus sp. by 16 S rRNA gene sequence analysis. The bacteriocin produced by strain GI-9, namely, laterosporulin was purified from supernatant of the culture grown under optimal conditions using hydrophobic interaction chromatography and reverse-phase HPLC. The bacteriocin was active against a wide range of Gram-positive and Gram-negative bacteria. MALDI-TOF experiments determined the precise molecular mass of the peptide to be of 5.6 kDa and N-terminal sequencing of the thermo-stable peptide revealed low similarity with existing antimicrobial peptides. The putative open reading frame (ORF encoding laterosporulin and its surrounding genomic region was fished out from the draft genome sequence of GI-9. Sequence analysis of the putative bacteriocin gene did not show significant similarity to any reported bacteriocin producing genes in database. CONCLUSIONS: We have identified a bacteriocin producing strain GI-9, belonging to the genus Brevibacillus sp. Biochemical and genomic characterization of laterosporulin suggests it as a novel bacteriocin with broad spectrum antibacterial activity.

Identification, purification and characterization of laterosporulin, a novel bacteriocin produced by Brevibacillus sp. strain GI-9.

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Singh, Pradip Kumar; Chittpurna; Ashish; Sharma, Vikas; Patil, Prabhu B; Korpole, Suresh

2012-01-01

Bacteriocins are antimicrobial peptides that are produced by bacteria as a defense mechanism in complex environments. Identification and characterization of novel bacteriocins in novel strains of bacteria is one of the important fields in bacteriology. The strain GI-9 was identified as Brevibacillus sp. by 16 S rRNA gene sequence analysis. The bacteriocin produced by strain GI-9, namely, laterosporulin was purified from supernatant of the culture grown under optimal conditions using hydrophobic interaction chromatography and reverse-phase HPLC. The bacteriocin was active against a wide range of Gram-positive and Gram-negative bacteria. MALDI-TOF experiments determined the precise molecular mass of the peptide to be of 5.6 kDa and N-terminal sequencing of the thermo-stable peptide revealed low similarity with existing antimicrobial peptides. The putative open reading frame (ORF) encoding laterosporulin and its surrounding genomic region was fished out from the draft genome sequence of GI-9. Sequence analysis of the putative bacteriocin gene did not show significant similarity to any reported bacteriocin producing genes in database. We have identified a bacteriocin producing strain GI-9, belonging to the genus Brevibacillus sp. Biochemical and genomic characterization of laterosporulin suggests it as a novel bacteriocin with broad spectrum antibacterial activity.

Co-fermentation of the main sugar types from a beechwood organosolv hydrolysate by several strains of Bacillus coagulans results in effective lactic acid production

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Robert Glaser

2018-06-01

Full Text Available Bacillus coagulans is an interesting facultative anaerobic microorganism for biotechnological production of lactic acid that arouses interest. To determine the efficiency of biotechnological production of lactic acid from lignocellulosic feedstock hydrolysates, five Bacillus coagulans strains were grown in lignocellulose organosolv hydrolysate from ethanol/water-pulped beechwood. Parameter estimation based on a Monod-type model was used to derive the basic key parameters for a performance evaluation of the batch process. Three of the Bacillus coagulans strains, including DSM No. 2314, were able to produce lactate, primarily via uptake of glucose and xylose. Two other strains were identified as having the ability of utilizing cellobiose to a high degree, but they also had a lower affinity to xylose. The lactate yield concentration varied from 79.4 ± 2.1 g/L to 93.7 ± 1.4 g/L (85.4 ± 4.7 % of consumed carbohydrates from the diluted organosolv hydrolysate.

An Interspecies Signaling System Mediated by Fusaric Acid Has Parallel Effects on Antifungal Metabolite Production by Pseudomonas protegens Strain Pf-5 and Antibiosis of Fusarium spp.

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Quecine, Maria Carolina; Kidarsa, Teresa A.; Goebel, Neal C.; Shaffer, Brenda T.; Henkels, Marcella D.; Zabriskie, T. Mark

2015-01-01

Pseudomonas protegens strain Pf-5 is a rhizosphere bacterium that suppresses soilborne plant diseases and produces at least seven different secondary metabolites with antifungal properties. We derived mutants of Pf-5 with single and multiple mutations in biosynthesis genes for seven antifungal metabolites: 2,4-diacetylphoroglucinol (DAPG), pyrrolnitrin, pyoluteorin, hydrogen cyanide, rhizoxin, orfamide A, and toxoflavin. These mutants were tested for inhibition of the pathogens Fusarium verticillioides and Fusarium oxysporum f. sp. pisi. Rhizoxin, pyrrolnitrin, and DAPG were found to be primarily responsible for fungal antagonism by Pf-5. Previously, other workers showed that the mycotoxin fusaric acid, which is produced by many Fusarium species, including F. verticillioides, inhibited the production of DAPG by Pseudomonas spp. In this study, amendment of culture media with fusaric acid decreased DAPG production, increased pyoluteorin production, and had no consistent influence on pyrrolnitrin or orfamide A production by Pf-5. Fusaric acid also altered the transcription of biosynthetic genes, indicating that the mycotoxin influenced antibiotic production by Pf-5 at the transcriptional level. Addition of fusaric acid to the culture medium reduced antibiosis of F. verticillioides by Pf-5 and derivative strains that produce DAPG but had no effect on antibiosis by Pf-5 derivatives that suppressed F. verticillioides due to pyrrolnitrin or rhizoxin production. Our results demonstrated the importance of three compounds, rhizoxin, pyrrolnitrin, and DAPG, in suppression of Fusarium spp. by Pf-5 and confirmed that an interspecies signaling system mediated by fusaric acid had parallel effects on antifungal metabolite production and antibiosis by the bacterial biological control organism. PMID:26655755

Selected wild strains of Agaricus bisporus produce high yields of mushrooms at 25°C.

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Navarro, Pilar; Savoie, Jean-Michel

2015-01-01

To cultivate the button mushroom Agaricus bisporus in warm countries or during summer in temperate countries, while saving energy, is a challenge that could be addressed by using the biological diversity of the species. The objective was to evaluate the yield potential of eight wild strains previously selected in small scale experiments for their ability to produce mature fruiting bodies at 25°C and above. Culture units of 8 kg of compost were used. The yield expressed as weight or number per surface unit and earliness of fruiting were recorded during cultivation in climatic rooms at 17, 25 or 30°C. Only strains of A. bisporus var. burnettii were able to fruit at 30°C. At 25°C they produced the highest yields (27 kg m(-2)) and had best earliness. The yields at 25°C for the strains of A. bisporus var. bisporus ranged from 12 to 16 kg m(-2). The yield ratios 25°C/17°C ranged from 0.8 to 1.2. The variety burnettii originated in the Sonoran Desert in California showed adaptation for quickly producing fruiting bodies at high temperature when humidity conditions were favorable. Strains of the variety bisporus showed interesting potentials for their ability to produce mature fruiting bodies at higher temperature than present cultivars and might be used in breeding programs. Copyright © 2012 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Biofortification of folates in white wheat bread by selection of yeast strain and process.

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Hjortmo, Sofia; Patring, Johan; Jastrebova, Jelena; Andlid, Thomas

2008-09-30

We here demonstrate that folate content in yeast fermented food can be dramatically increased by using a proper (i) yeast strain and (ii) cultivation procedure for the selected strain prior to food fermentation. Folate levels were 3 to 5-fold higher in white wheat bread leavened with a Saccharomyces cerevisiae strain CBS7764, cultured in defined medium and harvested in the respiro-fermentative phase of growth prior to dough preparation (135-139 microg/100 dry matter), compared to white wheat bread leavened with commercial Baker's yeast (27-43 microg/100 g). The commercial Baker's yeast strain had been industrially produced, using a fed-batch process, thereafter compressed and stored in the refrigerator until bakings were initiated. This strategy is an attractive alternative to fortification of bread with synthetically produced folic acid. By using a high folate producing strain cultured a suitable way folate levels obtained were in accordance with folic acid content in fortified cereal products.

Biotechnological conversion of waste cooking olive oil into lipid-rich biomass using Aspergillus and Penicillium strains.

Science.gov (United States)

Papanikolaou, S; Dimou, A; Fakas, S; Diamantopoulou, P; Philippoussis, A; Galiotou-Panayotou, M; Aggelis, G

2011-05-01

In this study, we have investigated the biochemical behaviour of Aspergillus sp. (five strains) and Penicillium expansum (one strain) fungi cultivated on waste cooking olive oil. The production of lipid-rich biomass was the main target of the work. In parallel, the biosynthesis of other extracellular metabolites (organic acids) and enzyme (lipase) and the substrate fatty acid specificity of the strains were studied. Carbon-limited cultures were performed on waste oil, added in the growth medium at 15g l(-1) , and high biomass quantities were produced (up to c.18g l(-1) , conversion yield of c. 1·0 g of dry biomass formed per g of fat consumed or higher). Cellular lipids were accumulated in notable quantities in almost all cultures. Aspergillus sp. ATHUM 3482 accumulated lipid up to 64·0% (w/w) in dry fungal mass. In parallel, extracellular lipase activity was quantified, and it was revealed to be strain and fermentation time dependent, with a maximum quantity of 645 U ml(-1) being obtained by Aspergillus niger NRRL 363. Storage lipid content significantly decreased at the stationary growth phase. Some differences in the fatty acid composition of both cellular and residual lipids when compared with the initial substrate fat used were observed; in various cases, cellular lipids more saturated and enriched with arachidic acid were produced. Aspergillus strains produced oxalic acid up to 5·0 g l(-1) . Aspergillus and Penicillium strains are able to convert waste cooking olive oil into high-added-value products.   Increasing fatty wastes amounts are annually produced. The current study provided an alternative way of biovalourization of these materials, by using them as substrates, to produce added-value compounds. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

Rewiring a secondary metabolite pathway towards itaconic acid production in Aspergillus niger.

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Hossain, Abeer H; Li, An; Brickwedde, Anja; Wilms, Lars; Caspers, Martien; Overkamp, Karin; Punt, Peter J

2016-07-28

The industrially relevant filamentous fungus Aspergillus niger is widely used in industry for its secretion capabilities of enzymes and organic acids. Biotechnologically produced organic acids promise to be an attractive alternative for the chemical industry to replace petrochemicals. Itaconic acid (IA) has been identified as one of the top twelve building block chemicals which have high potential to be produced by biotechnological means. The IA biosynthesis cluster (cadA, mttA and mfsA) has been elucidated in its natural producer Aspergillus terreus and transferred to A. niger to enable IA production. Here we report the rewiring of a secondary metabolite pathway towards further improved IA production through the overexpression of a putative cytosolic citrate synthase citB in a A. niger strain carrying the IA biosynthesis cluster. We have previously shown that expression of cadA from A. terreus results in itaconic acid production in A. niger AB1.13, albeit at low levels. This low-level production is boosted fivefold by the overexpression of mttA and mfsA in itaconic acid producing AB1.13 CAD background strains. Controlled batch cultivations with AB1.13 CAD + MFS + MTT strains showed increased production of itaconic acid compared with AB1.13 CAD strain. Moreover, preliminary RNA-Seq analysis of an itaconic acid producing AB1.13 CAD strain has led to the identification of the putative cytosolic citrate synthase citB which was induced in an IA producing strain. We have overexpressed citB in a AB1.13 CAD + MFS + MTT strain and by doing so hypothesize to have targeted itaconic acid production to the cytosolic compartment. By overexpressing citB in AB1.13 CAD + MFS + MTT strains in controlled batch cultivations we have achieved highly increased titers of up to 26.2 g/L IA with a productivity of 0.35 g/L/h while no CA was produced. Expression of the IA biosynthesis cluster in Aspergillus niger AB1.13 strain enables IA production. Moreover, in the AB1.13 CAD

Efficient production of lignocellulolytic enzymes xylanase, β-xylosidase, ferulic acid esterase and β-glucosidase by the mutant strain Aspergillus awamori 2B.361 U2/1

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Leda Maria Fortes Gottschalk

2013-01-01

Full Text Available The production of xylanase, β-xylosidase, ferulic acid esterase and β-glucosidase by Aspergillus awamori 2B.361 U2/1, a hyper producer of glucoamylase and pectinase, was evaluated using selected conditions regarding nitrogen nutrition. Submerged cultivations were carried out at 30 ºC and 200 rpm in growth media containing 30 g wheat bran/L as main carbon source and either yeast extract, ammonium sulfate, sodium nitrate or urea, as nitrogen sources; in all cases it was used a fixed molar carbon to molar nitrogen concentration of 10.3. The use of poor nitrogen sources favored the accumulation of xylanase, β-xylosidase and ferulic acid esterase to a peak concentrations of 44,880; 640 and 118 U/L, respectively, for sodium nitrate and of 34,580, 685 and 170 U/L, respectively, for urea. However, the highest β-glucosidase accumulation of 10,470 U/L was observed when the rich organic nitrogen source yeast extract was used. The maxima accumulation of filter paper activity, xylanase, β-xylosidase, ferulic acid esterase and β-glucosidase by A. awamori 2B.361 U2/1 was compared to that produced by Trichoderma reesei Rut-C30. The level of β-glucosidase was over 17-fold higher for the Aspergillus strain, whereas the levels of xylanase and β-xylosidase were over 2-fold higher. This strain also produced ferulic acid esterase (170 U/L, which was not detected in the T. reesei culture.

Construction and evaluation of an exopolysaccharide-producing engineered bacterial strain by protoplast fusion for microbial enhanced oil recovery.

Science.gov (United States)

Sun, Shanshan; Luo, Yijing; Cao, Siyuan; Li, Wenhong; Zhang, Zhongzhi; Jiang, Lingxi; Dong, Hanping; Yu, Li; Wu, Wei-Min

2013-09-01

Enterobacter cloacae strain JD, which produces water-insoluble biopolymers at optimal temperature of 30°C, and a thermophilic Geobacillus strain were used to construct an engineered strain for exopolysaccharide production at high temperatures by protoplast fusion. The obtained fusant strain ZR3 produced exopolysaccharides at up to 45°C with optimal growth temperature at 35°C. The fusant produced exopolysaccharides of approximately 7.5 g/L or more at pH between 7.0 and 9.0. The feasibility of the enhancement of crude oil recovery with the fusant was tested in a sand-packed column at 40°C. The results demonstrated that bioaugmentation of the fusant was promising approach for MEOR. Mass growth of the fusant was confirmed in fermentor tests. Copyright © 2013 Elsevier Ltd. All rights reserved.

Purification and genetic characterisation of the novel bacteriocin LS2 produced by the human oral strain Lactobacillus salivarius BGHO1.

Science.gov (United States)

Busarcevic, Milos; Dalgalarrondo, Michèle

2012-08-01

The aim of this study was to investigate the antimicrobial potential of Lactobacillus salivarius BGHO1, a human oral strain with probiotic characteristics and a broad inhibitory spectrum both against Gram-positive and Gram-negative pathogens. Here we present the bacteriocin LS2, an extremely pH- and heat-stable peptide with antilisterial activity. LS2 is a novel member of the class IId bacteriocins, unique among all currently characterised bacteriocins. It is somewhat similar to putative bacteriocins from several oral streptococci, including the cariogenic Streptococcus mutans. LS2 is a 41-amino-acid, highly hydrophobic cationic peptide of 4115.1Da that is sensitive to proteolytic enzymes. LS2 was purified from cells of strain BGHO1 by solvent extraction and reverse-phase chromatography. Mass spectrometry was used to determine the molecular mass of the purified peptide. N-terminal amino acid sequencing enabled identification of the LS2 structural gene bacls2 by a reverse genetics approach. Downstream of the bacls2 gene, two bacteriocin-like genes were found, named blp1a and blp1b, and one putative bacteriocin immunity gene named bimlp. We also present the identification of the 242-kb megaplasmid pMPHO1 by pulsed-field gel electrophoresis, which harbours the genes bacls2, blp1a, blp1b and bimlp. Two peptides with antimicrobial activity, whose approximate sizes corresponded to those of blp1a and blp1b, were identified only after culturing strain BGHO1 in a chemically defined medium. This study demonstrated the capacity of Lactobacillus salivarius BGHO1 to produce multiple bacteriocins and further established this strain as a promising probiotic candidate. Copyright © 2012 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

CrdR function in a curdlan-producing Agrobacterium sp. ATCC31749 strain.

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Yu, Xiaoqin; Zhang, Chao; Yang, Liping; Zhao, Lamei; Lin, Chun; Liu, Zhengjie; Mao, Zichao

2015-02-10

Agrobacterium sp. ATCC31749 is an efficient curdlan producer at low pH and under nitrogen starvation. The helix-turn-helix transcriptional regulatory protein (crdR) essential for curdlan production has been analyzed, but whether crdR directly acts to cause expression of the curdlan biosynthesis operon (crdASC) is uncertain. To elucidate the molecular function of crdR in curdlan biosynthesis, we constructed a crdR knockout mutant along with pBQcrdR and pBQNcrdR vectors with crdR expression driven by a T5 promoter and crdR native promoter, respectively. Also, we constructed a pAG with the green fluorescent protein (GFP) gene driven by a curdlan biosynthetic operon promoter (crdP) to measure the effects of crdR expression on curdlan biosynthesis. Compared with wild-type (WT) strain biomass production, the biomass of the crdR knockout mutant was not significantly different in either exponential or stationary phases of growth. Mutant cells were non-capsulated and planktonic and produced significantly less curdlan. WT cells were curdlan-capsulated and aggregated in the stationery phase. pBQcrdR transformed to the WT strain had a 38% greater curdlan yield and pBQcrdR and pBQNcrdR transformed to the crdR mutant strain recovered 18% and 105% curdlan titers of the WT ATCC31749 strain, respectively. Consistent with its function of promoting curdlan biosynthesis, curdlan biosynthetic operon promoter (crdP) controlled GFP expression caused the transgenic strain to have higher GFP relative fluorescence in the WT strain, and no color change was observed with low GFP relative fluorescence in the crdR mutant strain as evidenced by fluorescent microscopy and spectrometric assay. q-RT-PCR revealed that crdR expression in the stationary phase was greater than in the exponential phase, and crdR overexpression in the WT strain increased crdA, crdS, and crdC expression. We also confirmed that purified crdR protein can specifically bind to the crd operon promoter region, and we inferred

Enhanced saturated fatty acids accumulation in cultures of newly-isolated strains of Schizochytrium sp. and Thraustochytriidae sp. for large-scale biodiesel production.

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Wang, Qiuzhen; Sen, Biswarup; Liu, Xianhua; He, Yaodong; Xie, Yunxuan; Wang, Guangyi

2018-08-01

Heterotrophic marine protists (Thraustochytrids) have received increasingly global attention as a renewable, sustainable and alternative source of biodiesel because of their high ability of saturated fatty acids (SFAs) accumulation. Yet, the influence of extrinsic factors (nutrients and environmental conditions) on thraustochytrid culture and optimal conditions for high SFAs production are poorly described. In the present study, two different thraustochytrid strains, Schizochytrium sp. PKU#Mn4 and Thraustochytriidae sp. PKU#Mn16 were studied for their growth and SFAs production profiles under various conditions (carbon, nitrogen, temperature, pH, KH 2 PO 4 , salinity, and agitation speed). Of the culture conditions, substrates (C and N) source and conc., temperature, and agitation speed significantly influenced the cell growth and SFAs production of both strains. Although both the strains were capable of growth and SFAs production in the broad range of culture conditions, their physiological responses to KH 2 PO 4 , pH, and salinity were dissimilar. Under their optimal batch culture conditions, peak SFAs productions of 3.3g/L and 2.2g/L with 62% and 49% SFAs contents (relative to total fatty acids) were achieved, respectively. The results of 5-L fed-batch fermentation under optimal conditions showed a nearly 4.5-fold increase in SFAs production (i.e., 7.5g/L) by both strains compared to unoptimized conditions. Of the two strains, the quality of biodiesel produced from the fatty acids of PKU#Mn4 met the biodiesel standard defined by ASTM6751. This study, to the knowledge of the authors, is the first comprehensive report of optimal fermentation conditions demonstrating enhanced SFAs production by strains belonging to two different thraustochytrid genera and provides the basis for large-scale biodiesel production. Copyright © 2018. Published by Elsevier B.V.

Isolation and characterization of novel 1,3-propanediol-producing Lactobacillus panis PM1 from bioethanol thin stillage.

Science.gov (United States)

Khan, Nurul H; Kang, Tae Sun; Grahame, Douglas A S; Haakensen, Monique C; Ratanapariyanuch, Kornsulee; Reaney, Martin J; Korber, Darren R; Tanaka, Takuji

2013-01-01

Conversion of glycerol to 1,3-propanediol (1,3-PDO) is an attractive option to increase the economic efficiency of the biofuel industry. A bacterial strain that produced 1,3-PDO in the presence of glycerol was isolated from thin stillage, the fermentation residue of bioethanol production. This 1,3-PDO-producing organism was identified as Lactobacillus panis through biochemical characteristics and by 16S rRNA sequencing. Characterization of the L. panis strain hereafter designated as PM1 revealed it was an aerotolerant acidophilic anaerobe able to grow over a wide range of temperatures; tolerant to high concentrations of sodium chloride, ethanol, acetic acid, and lactic acid; and resistant to many common antibiotics. L. panis PM1 could utilize glucose, lactose, galactose, maltose, xylose, and arabinose, but could not grow on sucrose or fructose. Production of 1,3-PDO by L. panis PM1 occurred only when glucose was available as the carbon source in the absence of oxygen. These metabolic characteristics strongly suggested NADH recycling for glucose metabolism is achieved through 1,3-PDO production by this strain. These characteristics classified L. panis PM1 within the group III heterofermentative lactic acid bacteria, which includes the well-characterized 1,3-PDO-producing strain, Lactobacillus reuteri. Metabolite production profiles showed that L. panis PM1 produced considerable amounts of succinic acid (~11-12 mM) from normal MRS medium, which distinguishes this strain from L. reuteri strains.

Succinic Acid: Technology Development and Commercialization

Directory of Open Access Journals (Sweden)

Nhuan P. Nghiem

2017-06-01

Full Text Available Succinic acid is a precursor of many important, large-volume industrial chemicals and consumer products. It was once common knowledge that many ruminant microorganisms accumulated succinic acid under anaerobic conditions. However, it was not until the discovery of Anaerobiospirillum succiniciproducens at the Michigan Biotechnology Institute (MBI, which was capable of producing succinic acid up to about 50 g/L under optimum conditions, that the commercial feasibility of producing the compound by biological processes was realized. Other microbial strains capable of producing succinic acid to high final concentrations subsequently were isolated and engineered, followed by development of fermentation processes for their uses. Processes for recovery and purification of succinic acid from fermentation broths were simultaneously established along with new applications of succinic acid, e.g., production of biodegradable deicing compounds and solvents. Several technologies for the fermentation-based production of succinic acid and the subsequent conversion to useful products are currently commercialized. This review gives a summary of the development of microbial strains, their fermentation, and the importance of the down-stream recovery and purification efforts to suit various applications in the context of their current commercialization status for biologically derived succinic acid.

Isolation and identification of a Candida digboiensis strain from an extreme acid mine drainage of the Lignite Mine, Gujarat.

Science.gov (United States)

Patel, Mitesh J; Tipre, Devayani R; Dave, Shailesh R

2009-12-01

An extremely acidic mine drainage (AMD) water sample was collected in 1998 and 2008 from Panandhro lignite mine, Gujarat, India. The yeast isolated from this sample was identified using mini API identification system, as a member of genus Candida. The major cellular fatty acids detected by FAME from the isolate are C(16:0) and C(18:2) (cis 9,12)/C(18:0alpha) as 25.23 and 19.5%, respectively. The isolate was identified as Candida digboiensis by 18S rRNA gene sequence analysis and designated as Candida digboiensis SRDyeast1. Phylogenetic analysis using D1/D2 variable domains showed that the closest relative of this strain is Candida blankii with 3% divergence. This organism has been reported for the first time from the lignite mine AMD sample, and for cellular fatty acid analysis. This yeast is able to survive in the AMD sample preserved at 10-42 degrees C temperature since last 10 years along with iron oxidizing microorganisms. It can grow in the presence of 40% glucose, 10% NaCl and in the pH range of 1 to 10. The isolate is capable of producing enzymes like protease and lipase. This isolate differs from the type strain Candida digboiensis in as many as six physiological and metabolic characteristics.

Genetic Diversity Among Botulinum Neurotoxin Producing Clostridial Strains

Energy Technology Data Exchange (ETDEWEB)

Hill, K K; Smith, T J; Helma, C H; Ticknor, L O; Foley, B T; Svennson, R T; Brown, J L; Johnson, E A; Smith, L A; Okinaka, R T; Jackson, P J; Marks, J D

2006-07-06

Clostridium botulinum is a taxonomic designation for many diverse anaerobic spore forming rod-shaped bacteria which have the common property of producing botulinum neurotoxins (BoNTs). The BoNTs are exoneurotoxins that can cause severe paralysis and even death in humans and various other animal species. A collection of 174 C. botulinum strains were examined by amplified fragment length polymorphism (AFLP) analysis and by sequencing of the 16S rRNA gene and BoNT genes to examine genetic diversity within this species. This collection contained representatives of each of the seven different serotypes of botulinum neurotoxins (BoNT A-G). Analysis of the16S rRNA sequences confirmed earlier reports of at least four distinct genomic backgrounds (Groups I-IV) each of which has independently acquired one or more BoNT serotypes through horizontal gene transfer. AFLP analysis provided higher resolution, and can be used to further subdivide the four groups into sub-groups. Sequencing of the BoNT genes from serotypes A, B and E in multiple strains confirmed significant sequence variation within each serotype. Four distinct lineages within each of the BoNT A and B serotypes, and five distinct lineages of serotype E strains were identified. The nucleotide sequences of the seven serotypes of BoNT were compared and show varying degrees of interrelatedness and recombination as has been previously noted for the NTNH gene which is linked to BoNT. These analyses contribute to the understanding of the evolution and phylogeny within this species and assist in the development of improved diagnostics and therapeutics for treatment of botulism.

Selection of daunorubicin-producing strain S. Coeruleorubidus by plasma radiation technology

International Nuclear Information System (INIS)

Jiang Shichun; Wu Jianping; Bai Hua

2001-01-01

The authors reported the results of mutagenesis by nitrogen plasma radiation with energy from 65 to 80 keV and dose from 9.6 x 10 9 to 1.5 x 10 11 /cm 2 in antineoplastic antibiotics daunorubicin-producing S. Coeruleorubidus. The relationship between death rate and radiation dose was formulated by computer and the formula. It was fit to a biological single-hit curve. The obtained high-producing mutagenic strain 137 was tested for its production property. The result showed that it could increase the daunorubicin potency by 25.8% in productive tanks of fermentation

Characterization of a novel biosurfactant produced by Staphylococcus sp. strain 1E with potential application on hydrocarbon bioremediation.

Science.gov (United States)

Eddouaouda, Kamel; Mnif, Sami; Badis, Abdelmalek; Younes, Sonia Ben; Cherif, Slim; Ferhat, Samira; Mhiri, Najla; Chamkha, Mohamed; Sayadi, Sami

2012-08-01

A biosurfactant-producing bacterium (Staphylococcus sp. strain 1E) was isolated from an Algerian crude oil contaminated soil. Biosurfactant production was tested with different carbon sources using the surface tension measurement and the oil displacement test. Olive oil produced the highest reduction in surface tension (25.9 dynes cm(-1)). Crude oil presented the best substrate for 1E biosurfactant emulsification activity. The biosurfactant produced by strain 1E reduced the growth medium surface tension below 30 dynes cm(-1). This reduction was also obtained in cell-free filtrates. Biosurfactant produced by strain 1E showed stability in a wide range of pH (from 2 to 12), temperature (from 4 to 55 °C) and salinity (from 0 to 300 g l(-1)) variations. The biosurfactant produced by strain 1E belonged to lipopeptide group and also constituted an antibacterial activity againt the pathogenic bacteria such as Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis. Phenanthrene solubility in water was enhanced by biosurfactant addition. Our results suggest that the 1E biosurfactant has interesting properties for its application in bioremediation of hydrocarbons contaminated sites. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lasiojasmonates A-C, three jasmonic acid esters produced by Lasiodiplodia sp., a grapevine pathogen.

Science.gov (United States)

Andolfi, Anna; Maddau, Lucia; Cimmino, Alessio; Linaldeddu, Benedetto T; Basso, Sara; Deidda, Antonio; Serra, Salvatorica; Evidente, Antonio

2014-07-01

In this study, a strain (BL 101) of a species of Lasiodiplodia, not yet formally described, which was isolated from declining grapevine plants showing wedge-shaped cankers, was investigated for its ability to produce in vitro bioactive secondary metabolites. From culture filtrates of this strain three jasmonic acid esters, named lasiojasmonates A-C and 16-O-acetylbotryosphaerilactones A and C were isolated together with (1R,2R)-jasmonic acid, its methyl ester, botryosphaerilactone A, (3S,4R,5R)-4-hydroxymethyl-3,5-dimethyldihydro-2-furanone and (3R,4S)-botryodiplodin. The structures of lasiojasmonates A-C were established by spectroscopic methods as (1R*,2R*,3'S*,4'R*,5'R*)-4-hydroxymethyl-3,5-dimethyldihydro-2-furanone, (1R*,2R*,3'S*,4'R*,5'R*,10'R*,12'R*,13'R*,14'S*) and (1R*,2R*,3'S*,4'R*,5'R*,10'S*,12'R*,13'R*,14'S*)-4-(4-hydroxymethyl-3,5-dimethyltetrahydro-furan-2-yloxymethyl)-3,5-dimethyldihydro-2-furanones jasmonates (1, 4 and 5). The structures of 16-O-acetylbotryosphaerilactones A and C were determined by comparison of their spectral data with those of the corresponding acetyl derivatives obtained by acetylation of botryosphaerilactone A. The metabolites isolated, except 4 and 5, were tested at 1mg/mL on leaves of grapevine cv. Cannonau and cork oak using the leaf puncture assay. They were also tested on detached grapevine leaves at 0.5mg/mL and tomato cuttings at 0.1mg/mL. In all phytotoxic assays only jasmonic acid was found to be active. All metabolites were inactive in the zootoxic assay at 50 μg/mL. Copyright © 2014. Published by Elsevier Ltd.

Mutant E. coli strain with increased succinic acid production

Science.gov (United States)

Donnelly, Mark; Millard, Cynthia S.; Stols, Lucy

2001-09-25

A method for isolating succinic acid producing bacteria is provided comprising increasing the biomass of an organism which lacks the ability to catabolize pyruvate, and then subjecting the biomass to glucose-rich medium in an anaerobic environment to enable pyruvate-catabolizing mutants to grow. The invention also provides for a mutant that produces high amounts of succinic acid, which has been derived from a parent which lacked the genes for pyruvate formate lyase and lactate dehydrogenase, and which belongs to the E.coli Group of Bacteria.

Mutant E. coli strain with increased succinic acid production

Science.gov (United States)

Donnelly, Mark; Millard, Cynthia S.; Stols, Lucy

1998-01-01

A method for isolating succinic acid producing bacteria is provided comprising increasing the biomass of an organism which lacks the ability to catabolize pyruvate, and then subjecting the biomass to glucose-rich medium in an anaerobic environment to enable pyruvate-catabolizing mutants to grow. The invention also provides for a mutant that produces high amounts of succinic acid, which as been derived from a parent which lacked the genes for pyruvate formate lyase and lactate dehydrogenase, and which belongs to the E.coli Group of Bacteria.

Lactic acid bacteria from raw milk as potentially beneficial strains to prevent bovine mastitis.

Science.gov (United States)

Espeche, M Carolina; Pellegrino, Matías; Frola, Ignacio; Larriestra, Alejandro; Bogni, Cristina; Nader-Macías, M E Fátima

2012-02-01

Bovine mastitis produces a wide variety of problems in the dairy farm. The treatment of this disease is based on the use of antibiotics which are not always effective. These drugs are also responsible for the presence of residues in the milk and the increase of antibiotic-resistant strains. Probiotic products were proposed as a valid alternative to antibiotic therapies and are also useful for the prevention of infectious syndromes. With the aim of designing a probiotic product to prevent bovine mastitis, lactic acid bacteria (LAB) were isolated from foremilk samples from different dairy farms in Córdoba-Argentina. One hundred and seventeen LAB were isolated and their beneficial characteristics such as the production of inhibitory substances, surface properties and production of exopolysaccharides (EPS) were assessed. Most of them displayed low degree of hydrophobicity, autoaggregation, EPS negative phenotype and were identified as Enterococcus hirae and Pediococcus pentosaceus. Nine LAB strains inhibited three indicator bacteria. Some isolates were pre-selected and genetically identified according to the results obtained. Antibiotic resistance and virulence factors were studied for the assessment of the safety of the strains. The results obtained were compared to those reported previously from samples obtained in the North-western area of the country and some differences were found. Copyright © 2012 Elsevier Ltd. All rights reserved.

Oleanolic acid alters bile acid metabolism and produces cholestatic liver injury in mice

Energy Technology Data Exchange (ETDEWEB)

Liu, Jie, E-mail: JLiu@kumc.edu [University of Kansas Medical Center, Kansas City, KS 66160 (United States); Zunyi Medical College, Zunyi 563003 (China); Lu, Yuan-Fu [University of Kansas Medical Center, Kansas City, KS 66160 (United States); Zunyi Medical College, Zunyi 563003 (China); Zhang, Youcai; Wu, Kai Connie [University of Kansas Medical Center, Kansas City, KS 66160 (United States); Fan, Fang [Cytopathology, University of Kansas Medical Center, Kansas City, KS 66160 (United States); Klaassen, Curtis D. [University of Kansas Medical Center, Kansas City, KS 66160 (United States)

2013-11-01

Oleanolic acid (OA) is a triterpenoids that exists widely in plants. OA is effective in protecting against hepatotoxicants. Whereas a low dose of OA is hepatoprotective, higher doses and longer-term use of OA produce liver injury. This study characterized OA-induced liver injury in mice. Adult C57BL/6 mice were given OA at doses of 0, 22.5, 45, 90, and 135 mg/kg, s.c., daily for 5 days, and liver injury was observed at doses of 90 mg/kg and above, as evidenced by increases in serum activities of alanine aminotransferase and alkaline phosphatase, increases in serum total bilirubin, as well as by liver histopathology. OA-induced cholestatic liver injury was further evidenced by marked increases of both unconjugated and conjugated bile acids (BAs) in serum. Gene and protein expression analysis suggested that livers of OA-treated mice had adaptive responses to prevent BA accumulation by suppressing BA biosynthetic enzyme genes (Cyp7a1, 8b1, 27a1, and 7b1); lowering BA uptake transporters (Ntcp and Oatp1b2); and increasing a BA efflux transporter (Ostβ). OA increased the expression of Nrf2 and its target gene, Nqo1, but decreased the expression of AhR, CAR and PPARα along with their target genes, Cyp1a2, Cyp2b10 and Cyp4a10. OA had minimal effects on PXR and Cyp3a11. Taken together, the present study characterized OA-induced liver injury, which is associated with altered BA homeostasis, and alerts its toxicity potential. - Highlights: • Oleanolic acid at higher doses and long-term use may produce liver injury. • Oleanolic acid increased serum ALT, ALP, bilirubin and bile acid concentrations. • OA produced feathery degeneration, inflammation and cell death in the liver. • OA altered bile acid homeostasis, affecting bile acid synthesis and transport.

Screening of mutant strains producing phytase from A. niger by 60Co γ-ray irradiation

International Nuclear Information System (INIS)

Yang Pingping; Wang Yan; Tao Wenyi

2004-01-01

60 Co γ-ray was used to irradiate Aspergillus niger 447-92 for screening the mutant strain of producing phytase, and the effects of mutation induction were determined and analyzed. A mutant strain A. niger 496-1 with high level of phytase was selected, the phytase properties of A. niger 496-1 were analyzed

Effects of phosphoenolpyruvate carboxylase desensitization on glutamic acid production in Corynebacterium glutamicum ATCC 13032.

Science.gov (United States)

Wada, Masaru; Sawada, Kazunori; Ogura, Kotaro; Shimono, Yuta; Hagiwara, Takuya; Sugimoto, Masakazu; Onuki, Akiko; Yokota, Atsushi

2016-02-01

Phosphoenolpyruvate carboxylase (PEPC) in Corynebacterium glutamicum ATCC13032, a glutamic-acid producing actinobacterium, is subject to feedback inhibition by metabolic intermediates such as aspartic acid and 2-oxoglutaric acid, which implies the importance of PEPC in replenishing oxaloacetic acid into the TCA cycle. Here, we investigated the effects of feedback-insensitive PEPC on glutamic acid production. A single amino-acid substitution in PEPC, D299N, was found to relieve the feedback control by aspartic acid, but not by 2-oxoglutaric acid. A simple mutant, strain R1, having the D299N substitution in PEPC was constructed from ATCC 13032 using the double-crossover chromosome replacement technique. Strain R1 produced glutamic acid at a concentration of 31.0 g/L from 100 g/L glucose in a jar fermentor culture under biotin-limited conditions, which was significantly higher than that of the parent, 26.0 g/L (1.19-fold), indicative of the positive effect of desensitized PEPC on glutamic acid production. Another mutant, strain DR1, having both desensitized PEPC and PYK-gene deleted mutations, was constructed in a similar manner using strain D1 with a PYK-gene deleted mutation as the parent. This mutation had been shown to enhance glutamic acid production in our previous study. Although marginal, strain D1 produced higher glutamic acid, 28.8 g/L, than ATCC13032 (1.11-fold). In contrast, glutamic acid production by strain DR-1 was elevated up to 36.9 g/L, which was 1.42-fold higher than ATCC13032 and significantly higher than the other three strains. The results showed a synergistic effect of these two mutations on glutamic acid production in C. glutamicum. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Detection and Characterization of Histamine-Producing Strains of Photobacterium damselae subsp. damselae Isolated from Mullets

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Marcello Trevisani

2017-06-01

Full Text Available Photobacterium damselae subsp. damselae (Pdd is considered to be an emerging pathogen of marine fish and has also been implicated in cases of histamine food poisoning. In this study, eight strains isolated from mullets of the genera Mugil and Liza captured in the Ligurian Sea were characterized, and a method to detect histamine-producing Pdd from fish samples was developed. The histamine-producing potential of the strains was evaluated in culture media (TSB+ using a histamine biosensor. Subsequently, two strains were used to contaminate mackerel fillets (4 or 40 CFU/g, simulating a cross-contamination on the selling fish stalls. Sample homogenates were enriched in TSB+. The cultures were then inoculated on thiosulfate-citrate-bile salts-sucrose agar (TCBS and the dark green colonies were cultured on Niven agar. The violet isolates were characterized using specific biochemical and PCR based tests. All Pdd strains were histamine producers, yielding concentration varying from 167 and 8977 µg/mL in TSB+ cultures incubated at 30 °C for 24 h. Pdd colonies were detected from the inoculated mackerel samples and their histidine decarboxylase gene was amplified using species-specific primer pairs designed for this study. The results indicate that mullets can be source of Pdd and the fish retailers needs to evaluate the risk posed by cross-contamination on the selling fish stalls.

Isolation, Fermentation Optimization and Performance Studies of a Novel Biosurfactant Producing Strain Bacillus amyloliquefaciens

OpenAIRE

Zhang, W.; Zhang, X.; Cui, H.

2015-01-01

In this research, biosurfactant-producing bacteria were isolated from the outlet sludge of a canteen and one promising strain was identified through 16S rDNA sequence as Bacillus amyloliquefaciens. This strain can utilize water-soluble carbon source and the FT-IR analysis indicated the biosurfactant was probably glycolipids. Further factors (fermentation time, temperature, carbon source, nitrogen source, ion concentration) affecting the biosurfactant production were determined. The optimum fe...

Antagonistic effect of chosen lactic acid bacteria strains on Yersinia enterocolitica species in model set-ups, meat and fermented sausages.

Science.gov (United States)

Gomółka-Pawlicka, M; Uradziński, J

2003-01-01

The present study was aimed at determining the influence of 15 strains of lactic acid bacteria on the growth of 8 Yersinia enterocolitica strains in model set-ups, and in meat and ageing fermented sausages. The investigations were performed within the framework of three alternate stages which differed in respect to the products studied, the number of Lactobacillus sp. strains and, partly, methodological approach. The ratio between lactic acid bacteria and Yersinia enterocolitica strains studied was, depending on the variant of experiment, 1:1, 1:2 and 2:1, respectively. The study also considered water activity (aw) and pH of the products investigated. The results suggest that all the lactic acid bacteria strains used within the framework of the model set-ups had antagonistic effect on all the Salmonella sp. strains. However, this ability was not observed with respect to of tested lactic acid bacteria strains in meat and fermented sausage. This ability was possessed by one of the strains investigated--Lactobacillus helveticus T 78. The temperature and time of the incubation of sausages, but not aw and pH, were found to have a distinct influence on the antagonistic interaction between the bacteria tested.

Comparative transcriptome and phenotype analysis of acid-stressed Bacillus cereus strain ATCC 14579

NARCIS (Netherlands)

Mols, J.M.; Kranenburg, van Richard; Melis, van Clint; Moezelaar, Roy; Abee, Tjakko

2009-01-01

The food-borne human pathogen Bacillus cereus is found in environments that often have a low pH, such as food and soil. The physiological response upon exposure to several levels of acidity were investigated of B. cereus model strain ATCC 14579, to elucidate the response of B. cereus to acid stress.

Comparative transcriptome and phenotype analysis of acid-stressed Bacillus cereus strain ATCC 10987

NARCIS (Netherlands)

Mols, J.M.; Kranenburg, van Richard; Melis, van Clint; Moezelaar, Roy; Abee, Tjakko

2009-01-01

The food-borne human pathogen Bacillus cereus is found in environments that often have a low pH, such as food and soil. The physiological response upon exposure to several levels of acidity were investigated of B. cereus model strain ATCC 10987, to elucidate the response of B. cereus to acid stress.

Detection and characterization of bacteriocin-producing Lactococcus lactis strains Detecção e caracterização de Lactococcus lactis produtores de bacteriocinas

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Izildinha Moreno

1999-04-01

Full Text Available One hundred sixty seven strains of Lactococcus lactis were screened for bacteriocin production by well diffusion assay of GM17 agar. Fourteen (8.4% produced antimicrobial activity other than organic acids, bacteriophages or hydrogen peroxide. The frequency of bacteriocin production ranged from 2% in L. lactis subsp. cremoris up to 12% in L. lactis subsp. lactis. Antimicrobial activities were not observed in any strain of L. lactis subsp. lactis var. diacetylactis. Among thirteen bacteriocin-producing strains and two nisin-producing strains (L. lactis subsp. lactis ATCC 11454 and L. lactis subsp. lactis CNRZ 150, eight (53% were characterized as lactose-positive (Lac+ and proteinase-negative (Prt-. The bacteriocin-producing cultures were also characterized on the basis of plasmid content. All strains had 2 to 7 plasmids with molecular weights varying from 0.5 to 28.1 Mdal. Four strains (ITAL 435, ITAL 436, ITAL 437 and ITAL 438 showed identical profiles and the other were quite distinct.Um total de 167 linhagens de L. lactis foi selecionado para os testes de produção de bacteriocinas pelo método de difusão em poços em agar GM17. Desse total, 14 (8.4% produziram substâncias inibidoras que não foram associadas com ácidos orgânicos, peróxido de hidrogênio e bacteriófagos. A frequência de produção de bacteriocinas variou de 2% em L. lactis subsp. cremoris a 12% em L. lactis subsp. lactis. Nenhuma das linhagens de L. lactis subsp. lactis var. diacetylactis produziu substâncias inibidoras. De 13 linhagens produtoras de bacteriocinas e duas de nisina (L. lactis subsp. lactis ATCC 11454 e L. lactis subsp. lactis CNRZ 150, 8 (53% foram caracterizadas como lactose-positivas (Lac+ e proteinase-negativas (Prt-. As linhagens produtoras de bacteriocinas também foram caracterizadas no seu conteúdo de plasmídios. Elas apresentaram de 2 a 7 plasmídios, com pesos moleculares aproximados de 0.5 a 28.1 Mdal. Quatro linhagens (ITAL 435, ITAL 436

Primary Screening of 10 - Hydroxy - 2 - Decenoic Acid Productive Strains

Institute of Scientific and Technical Information of China (English)

无

2002-01-01

In this paper, eleven strains, which vere screened strictly from raw royal.jelly, soil and honeycomb etc. by means of dilution plate and spread plate methods, were cultured at 28°C for60 h with shaking. To determine whether they could yield 10-Hydroxy-2-decenoic acid during fermentation, gas chromatography and gas chromatography-mass spectrometry methods were used. The results showed that the strains BH002 and BH004. were both identified as Crvtococcaceae. where BH002 was primarily classified into Candida for possessing the abilities. The 10-HDA productivity of Candida BH002 and that of BH004 were 0.327% and 0.2648% respectively.

An Interspecies Signaling System Mediated by Fusaric Acid Has Parallel Effects on Antifungal Metabolite Production by Pseudomonas protegens Strain Pf-5 and Antibiosis of Fusarium spp.

Science.gov (United States)

Quecine, Maria Carolina; Kidarsa, Teresa A; Goebel, Neal C; Shaffer, Brenda T; Henkels, Marcella D; Zabriskie, T Mark; Loper, Joyce E

2015-12-11

Pseudomonas protegens strain Pf-5 is a rhizosphere bacterium that suppresses soilborne plant diseases and produces at least seven different secondary metabolites with antifungal properties. We derived mutants of Pf-5 with single and multiple mutations in biosynthesis genes for seven antifungal metabolites: 2,4-diacetylphoroglucinol (DAPG), pyrrolnitrin, pyoluteorin, hydrogen cyanide, rhizoxin, orfamide A, and toxoflavin. These mutants were tested for inhibition of the pathogens Fusarium verticillioides and Fusarium oxysporum f. sp. pisi. Rhizoxin, pyrrolnitrin, and DAPG were found to be primarily responsible for fungal antagonism by Pf-5. Previously, other workers showed that the mycotoxin fusaric acid, which is produced by many Fusarium species, including F. verticillioides, inhibited the production of DAPG by Pseudomonas spp. In this study, amendment of culture media with fusaric acid decreased DAPG production, increased pyoluteorin production, and had no consistent influence on pyrrolnitrin or orfamide A production by Pf-5. Fusaric acid also altered the transcription of biosynthetic genes, indicating that the mycotoxin influenced antibiotic production by Pf-5 at the transcriptional level. Addition of fusaric acid to the culture medium reduced antibiosis of F. verticillioides by Pf-5 and derivative strains that produce DAPG but had no effect on antibiosis by Pf-5 derivatives that suppressed F. verticillioides due to pyrrolnitrin or rhizoxin production. Our results demonstrated the importance of three compounds, rhizoxin, pyrrolnitrin, and DAPG, in suppression of Fusarium spp. by Pf-5 and confirmed that an interspecies signaling system mediated by fusaric acid had parallel effects on antifungal metabolite production and antibiosis by the bacterial biological control organism. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Bacillus amyloliquefaciens SUBSP. plantarum PROBIOTIC STRAINS AS PROTEASE PRODUCERS

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E. V. Маtseliukh

2015-04-01

Full Text Available Proteases from probiotic strains of the genus Bacillus, just like the antibiotics, bacteriocins and other hydrolytic enzymes, are one of the main factors that determine their biological activity. The aim of this work was to study the synthesis and biochemical properties of proteases from two strains Bacillus amyloliquefaciens subsp. plantarum UCM B-5139 and UCM B-5140 that included in the probiotic Endosporin. The cultivation of strains was carried out in flasks under rotating for two days. The influence of physico-chemical parameters of the reaction medium on proteolytic activity was studied on partially purified protease preparations. Lytic activity was determined by turbidimetric method. On the second day of cultivation B. amyloliquefaciens subsp. plantarum UCM В-5139 and UCM В-5140 synthesized the metal-dependent peptidase and serine protease, respectively. The optimum conditions of their action were the following: temperature 37–40 °C and pH 6.5–7.0. Isolated proteases are able to lyse the living cells of Staphylococcus aureus and Candida albicans. Thus we demonstrated that B. amyloliquefaciens subsp. plantarum UCM B-5140 and UCM B-5139, included in the probiotic veterinary preparation Endosporin, produced proteolytic enzymes that hydrolyze the native insoluble proteins (elastin, fibrin and collagen. These enzymes belong to the group of neutral metal-dependent and serine proteases. They are active under physiological conditions against gram-positive bacteria and yeasts. The application of these proteases in biotechnology is considered.

Volatile fatty acids influence on the structure of microbial communities producing PHAs

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Slawomir Ciesielski

2014-06-01

Full Text Available Polyhydroxyalkanoates (PHAs can be produced by microorganisms and are a biodegradable alternative to fossil-fuel based plastics. Currently, the focus is on reducing production costs by exploring alternative substrates for PHAs production, and on producing copolymers which are less brittle than monomers. Accordingly, this study used a substrate consisting of wastewater from waste-glycerol fermentation, supplemented with different amounts of acetic and propionic acids. These substrates were used to feed mixed microbial communities enriched from activated sludge in a sequencing batch reactor. A reactor supplemented with 2 mL of acetic acid produced 227.8 mg/L of a homopolymer of hydroxybutyrate (3HB; 4 mL of acetic acid produced 279.8 mg/L 3HB; whereas 4 mL of propionic acid produced 673.0 mg/L of a copolymer of 3HB and 3HV (hydroxyvalerate. Ribosomal Intergenic Spacer Analysis (RISA was used to show the differences between the communities created in the reactors. Thauera species predominated in biomass that produced 3HB; Paracoccus denitrificans in the biomass that produced 3HB-co-3HV. Because P. denitrificans produced the more desirable copolymer, it may be advantageous to promote its growth in PHAs-producing reactors by adding propionate.

Characterization, production, and purification of carnocin H, a bacteriocin produced by Carnobacterium 377.

Science.gov (United States)

Blom, H; Katla, T; Nissen, H; Holo, H

2001-10-01

Carnocin H, a bacteriocin produced by a Carnobacterium sp., inhibited lactic acid bacteria, clostridia, enterococci, and some Staphylococcus aureus strains. Some strains of Listeria and Pediococcus were also sensitive to carnocin H. The bacteriocin was produced during the late stationary growth phase. Carnocin H was purified by cation exchange chromatography and reverse phase chromatography. Amino acid sequence and composition indicate that carnocin H is a novel bacteriocin belonging to the class II bacteriocins. The bacteriocin consists of approximately 75 amino acid residues with a highly cationic N-terminal containing six succeeding lysines. Activity, as measured by agar diffusion zones, was reduced at increased pH values, levels of indicator bacteria, NaCl, agar, and soy oil.

Whole-Genome Characterization and Strain Comparison of VT2f-Producing Escherichia coli Causing Hemolytic Uremic Syndrome

Science.gov (United States)

Michelacci, Valeria; Bondì, Roslen; Gigliucci, Federica; Franz, Eelco; Badouei, Mahdi Askari; Schlager, Sabine; Minelli, Fabio; Tozzoli, Rosangela; Caprioli, Alfredo; Morabito, Stefano

2016-01-01

Verotoxigenic Escherichia coli infections in humans cause disease ranging from uncomplicated intestinal illnesses to bloody diarrhea and systemic sequelae, such as hemolytic uremic syndrome (HUS). Previous research indicated that pigeons may be a reservoir for a population of verotoxigenic E. coli producing the VT2f variant. We used whole-genome sequencing to characterize a set of VT2f-producing E. coli strains from human patients with diarrhea or HUS and from healthy pigeons. We describe a phage conveying the vtx2f genes and provide evidence that the strains causing milder diarrheal disease may be transmitted to humans from pigeons. The strains causing HUS could derive from VT2f phage acquisition by E. coli strains with a virulence genes asset resembling that of typical HUS-associated verotoxigenic E. coli. PMID:27584691

Draft Genome Sequence of the Microbispora sp. Strain ATCC-PTA-5024, Producing the Lantibiotic NAI-107

DEFF Research Database (Denmark)

Sosio, M.; Gallo, G.; Pozzi, R.

2014-01-01

We report the draft genome sequence of Microbispora sp. strain ATCC-PTA-5024, a soil isolate that produces NAI-107, a new lantibiotic with the potential to treat life-threatening infections caused by multidrug-resistant Gram-positive pathogens. The draft genome of strain Microbispora sp. ATCC...

Phylogenetic analysis of Bacillus subtilis strains applicable to natto (fermented soybean) production

Science.gov (United States)

Spore-forming Bacillus strains that produce extracellular poly-'-glutamic acid were screened for their application to natto (fermented soybean food) fermentation. Among the 365 strains, including B. subtilis and B. amyloliquefaciens, which we isolated from rice straw, 59 were capable of fermenting n...

Enhancing Fatty Acid Production of Saccharomyces cerevisiae as an Animal Feed Supplement.

Science.gov (United States)

You, Seung Kyou; Joo, Young-Chul; Kang, Dae Hee; Shin, Sang Kyu; Hyeon, Jeong Eun; Woo, Han Min; Um, Youngsoon; Park, Chulhwan; Han, Sung Ok

2017-12-20

Saccharomyces cerevisiae is used for edible purposes, such as human food or as an animal feed supplement. Fatty acids are also beneficial as feed supplements, but S. cerevisiae produces small amounts of fatty acids. In this study, we enhanced fatty acid production of S. cerevisiae by overexpressing acetyl-CoA carboxylase, thioesterase, and malic enzyme associated with fatty acid metabolism. The enhanced strain pAMT showed 2.4-fold higher fatty acids than the wild-type strain. To further increase the fatty acids, various nitrogen sources were analyzed and calcium nitrate was selected as an optimal nitrogen source for fatty acid production. By concentration optimization, 672 mg/L of fatty acids was produced, which was 4.7-fold higher than wild-type strain. These results complement the low level fatty acid production and make it possible to obtain the benefits of fatty acids as an animal feed supplement while, simultaneously, maintaining the advantages of S. cerevisiae.

Isolation and Fatty Acid Profile of Selected Microalgae Strains from the Red Sea for Biofuel Production

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Khalid M. Abu-Salah

2013-05-01

Full Text Available The isolation of lipid-rich autochthonous strains of microalgae is a crucial stage for the development of a microalgae-based biofuel production plant, as these microalgae already have the necessary adaptations to withstand competition, predation and the temperatures observed at each production site. This is particularly important in extreme climates such as in Saudi Arabia. Resorting to fluorescence activated cell sorting (FACS we screened for and isolated several microalgal strains from samples collected from the Red Sea. Relying on the fluorescence of BODIPY 505/515 (4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diazasindacene and growth performance, four promising candidates were identified and the total lipid content and fatty acid profile was assessed for biofuels production. Selected isolates were classified as chlorophytes, belonging to three different genera: Picochlorum, Nannochloris and Desmochloris. The lipid contents were assessed microscopically by means of BODIPY 505/515-associated fluorescence to detect intracellular lipid bodies, which revealed several lipid drops in all selected strains. This result was confirmed by lipid gravimetric determination, which demonstrated that all strains under study presented inner cell lipid contents ranging from 20% to 25% of the biomass dry weight. Furthermore, the fatty acid methyl esters profile of all strains seems ideal for biodiesel production due to a low degree of polyunsaturated fatty acid methyl esters and high amount of palmitic and oleic acids.

Analisa Asam Organik Dan Asam Amino Pada Natto Yang Difermentasi Oleh 7 Strain Bacillus Natto

OpenAIRE

SULISTYO, JOKO

1986-01-01

JOKO SUUSTYO. 1986. Analysis of organic acid and amino acid in natto fermented by 7 strains of Bacillus natto. Berita Biologi 3 (6): 277 - 282. The ability of seven strains of Bacillus natto produced a number of organic and amino acid components in natto were investigated. Raw, submerced and autoclaved soybeans for natto contained 1.15% 0.46% and 0.77% in organic acid and 0.19%, 0.30% and 0.30% in amino acid, while after fermentation those range were 0.36 - 0.90% in organic acid and 2.86 -6.0...

Effect of chromium on the fatty acid composition of two strains of Euglena gracilis

Energy Technology Data Exchange (ETDEWEB)

Rocchetta, Iara [Departamento de Biodiversidad y Biologia Experimental, Universidad de Buenos Aires, Pab. II, Ciudad Universitaria, 1428 Buenos Aires (Argentina)]. E-mail: rocchetta@bg.fcen.uba.ar; Mazzuca, Marcia [Departamento de Quimica, Facultad de Ciencias Naturales, Universidad de Patagonia, Comodoro Rivadavia, Chubut (Argentina); Conforti, Visitacion [Departamento de Biodiversidad y Biologia Experimental, Universidad de Buenos Aires, Pab. II, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Ruiz, Laura [Departamento de Biodiversidad y Biologia Experimental, Universidad de Buenos Aires, Pab. II, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Balzaretti, Vilma [Departamento de Quimica, Facultad de Ciencias Naturales, Universidad de Patagonia, Comodoro Rivadavia, Chubut (Argentina); Rios de Molina, Maria del Carmen [Departamento de Quimica Biologica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pab. II, Ciudad Universitaria, 1428 Buenos Aires (Argentina)

2006-05-15

The effect of hexavalent chromium on fatty acid composition was studied in two strains of Euglena gracilis; UTEX 753 (from the Culture Collection of Algae of Texas University, USA) and MAT (isolated from a highly polluted River). Both were grown in photoauxotrophic and photoheterotrophic conditions and exposed to two metal concentrations, one below and one above IC{sub 5}. The high malondialdehyde (MDA) levels (3 to 7-fold) obtained with chromium concentration above IC{sub 5}, suggested the existence of metal-induced lipid peroxidation. Total lipid content increased only with concentration below IC{sub 5}, whereas it was inhibited by higher metal concentration. Photoheterotrophic control strains exhibited a significantly higher proportion of saturated and polyunsaturated fatty acids. Polyunsaturated acids were most affected by chromium, especially those related to chloroplast structures. Ultra-structure studies showed clear thylakoid disorganization in all treated cells. The results indicate that hexavalent chromium affects levels of fatty acids, especially those related to photosynthetic activity. - Fatty acid evaluation in the presence of chromium in Euglena gracilis grown in different culture conditions.

Effect of chromium on the fatty acid composition of two strains of Euglena gracilis

International Nuclear Information System (INIS)

Rocchetta, Iara; Mazzuca, Marcia; Conforti, Visitacion; Ruiz, Laura; Balzaretti, Vilma; Rios de Molina, Maria del Carmen

2006-01-01

The effect of hexavalent chromium on fatty acid composition was studied in two strains of Euglena gracilis; UTEX 753 (from the Culture Collection of Algae of Texas University, USA) and MAT (isolated from a highly polluted River). Both were grown in photoauxotrophic and photoheterotrophic conditions and exposed to two metal concentrations, one below and one above IC 5 . The high malondialdehyde (MDA) levels (3 to 7-fold) obtained with chromium concentration above IC 5 , suggested the existence of metal-induced lipid peroxidation. Total lipid content increased only with concentration below IC 5 , whereas it was inhibited by higher metal concentration. Photoheterotrophic control strains exhibited a significantly higher proportion of saturated and polyunsaturated fatty acids. Polyunsaturated acids were most affected by chromium, especially those related to chloroplast structures. Ultra-structure studies showed clear thylakoid disorganization in all treated cells. The results indicate that hexavalent chromium affects levels of fatty acids, especially those related to photosynthetic activity. - Fatty acid evaluation in the presence of chromium in Euglena gracilis grown in different culture conditions

Acid Evolution of Escherichia coli K-12 Eliminates Amino Acid Decarboxylases and Reregulates Catabolism.

Science.gov (United States)

He, Amanda; Penix, Stephanie R; Basting, Preston J; Griffith, Jessie M; Creamer, Kaitlin E; Camperchioli, Dominic; Clark, Michelle W; Gonzales, Alexandra S; Chávez Erazo, Jorge Sebastian; George, Nadja S; Bhagwat, Arvind A; Slonczewski, Joan L

2017-06-15

Acid-adapted strains of Escherichia coli K-12 W3110 were obtained by serial culture in medium buffered at pH 4.6 (M. M. Harden, A. He, K. Creamer, M. W. Clark, I. Hamdallah, K. A. Martinez, R. L. Kresslein, S. P. Bush, and J. L. Slonczewski, Appl Environ Microbiol 81:1932-1941, 2015, https://doi.org/10.1128/AEM.03494-14). Revised genomic analysis of these strains revealed insertion sequence (IS)-driven insertions and deletions that knocked out regulators CadC (acid induction of lysine decarboxylase), GadX (acid induction of glutamate decarboxylase), and FNR (anaerobic regulator). Each acid-evolved strain showed loss of one or more amino acid decarboxylase systems, which normally help neutralize external acid (pH 5 to 6) and increase survival in extreme acid (pH 2). Strains from populations B11, H9, and F11 had an IS 5 insertion or IS-mediated deletion in cadC , while population B11 had a point mutation affecting the arginine activator adiY The cadC and adiY mutants failed to neutralize acid in the presence of exogenous lysine or arginine. In strain B11-1, reversion of an rpoC (RNA polymerase) mutation partly restored arginine-dependent neutralization. All eight strains showed deletion or downregulation of the Gad acid fitness island. Strains with the Gad deletion lost the ability to produce GABA (gamma-aminobutyric acid) and failed to survive extreme acid. Transcriptome sequencing (RNA-seq) of strain B11-1 showed upregulated genes for catabolism of diverse substrates but downregulated acid stress genes (the biofilm regulator ariR , yhiM , and Gad). Other strains showed downregulation of H 2 consumption mediated by hydrogenases ( hya and hyb ) which release acid. Strains F9-2 and F9-3 had a deletion of fnr and showed downregulation of FNR-dependent genes ( dmsABC , frdABCD , hybABO , nikABCDE , and nrfAC ). Overall, strains that had evolved in buffered acid showed loss or downregulation of systems that neutralize unbuffered acid and showed altered regulation of

Genomic mutational analysis of the impact of the classical strain improvement program on β-lactam producing Penicillium chrysogenum

NARCIS (Netherlands)

Salo, Oleksandr V; Ries, Marco; Medema, Marnix H; Lankhorst, Peter P; Vreeken, Rob J; Bovenberg, Roel A L; Driessen, Arnold J M

2015-01-01

BACKGROUND: Penicillium chrysogenum is a filamentous fungus that is employed as an industrial producer of β-lactams. The high β-lactam titers of current strains is the result of a classical strain improvement program (CSI) starting with a wild-type like strain more than six decades ago. This

Metabolic engineering of Pseudomonas fluorescens for the production of vanillin from ferulic acid.

Science.gov (United States)

Di Gioia, Diana; Luziatelli, Francesca; Negroni, Andrea; Ficca, Anna Grazia; Fava, Fabio; Ruzzi, Maurizio

2011-12-20

Vanillin is one of the most important flavors in the food industry and there is great interest in its production through biotechnological processes starting from natural substrates such as ferulic acid. Among bacteria, recombinant Escherichia coli strains are the most efficient vanillin producers, whereas Pseudomonas spp. strains, although possessing a broader metabolic versatility, rapidly metabolize various phenolic compounds including vanillin. In order to develop a robust Pseudomonas strain that can produce vanillin in high yields and at high productivity, the vanillin dehydrogenase (vdh)-encoding gene of Pseudomonas fluorescens BF13 strain was inactivated via targeted mutagenesis. The results demonstrated that engineered derivatives of strain BF13 accumulate vanillin if inactivation of vdh is associated with concurrent expression of structural genes for feruloyl-CoA synthetase (fcs) and hydratase/aldolase (ech) from a low-copy plasmid. The conversion of ferulic acid to vanillin was enhanced by optimization of growth conditions, growth phase and parameters of the bioconversion process. The developed strain produced up to 8.41 mM vanillin, which is the highest final titer of vanillin produced by a Pseudomonas strain to date and opens new perspectives in the use of bacterial biocatalysts for biotechnological production of vanillin from agro-industrial wastes which contain ferulic acid. Copyright © 2011 Elsevier B.V. All rights reserved.

Ruminant and industrially produced trans fatty acids

DEFF Research Database (Denmark)

Stender, Steen; Astrup, Arne; Dyerberg, Jørn

2008-01-01

% of the fatty acids in trans form compared to the content in ruminant fat which generally does not exceed 6%. In Western Europe, including Scandinavia, the average daily intake of IP-TFA has decreased during the recent decade due to societal pressure and a legislative ban, whereas the intake of RP-TFA has......Fatty acids of trans configuration in our food come from two different sources - industrially produced partially hydrogenated fat (IP-TFA) used in frying oils, margarines, spreads, and in bakery products, and ruminant fat in dairy and meat products (RP-TFA). The first source may contain up to 60...

Growth characteristics and enzyme production optimization of lipase Producing Strain

Science.gov (United States)

Zheng, Chaocheng

2018-01-01

55 samples from different regions were selected and screened by Rhodamine B flat transparent circle method to observe lipase producing effect, among which, LHY-1, identified as Serratia sp. has the characteristics of fast growth, high enzyme production and stable ability. The colony of this strain is white, the edge is smooth and tidy, the surface is moist, the cell is straight, rod-shaped, gram negative, 0.1-0.2 μm in diameter and, length 0.3-0.5 μm in length.

Influence of gastrointestinal system conditions on adhesion of exopolysaccharide-producing Lactobacillus delbrueckii subsp. bulgaricus strains to caco-2 cells

Directory of Open Access Journals (Sweden)

Derya Onal Darilmaz

2011-10-01

Full Text Available This study aimed to assess the transit tolerance of potential probiotic dairy Lactobacillus strains in human uppergastrointestinal tract in vitro, and to evaluate the effect of EPS production on the viability and adhesion of these strains. Survival and adhesion of two exopolysaccharide (EPS-producing L. delbrueckii subsp. bulgaricus strains (B3 and B2 and E. coli ATCC11229 were assessed after the exposure of different pH (gastric juice and gastric plus pancreatic juice challenges. In the artificial gastric juice (pH 2, both the viability of the strain B3 and B2 was decreased. Artificial juice treatments significantly reduced the adhesion to caco-2 cells (P< 0.05. High EPS-producing B3 survived better in the adverse gastrointestinal conditions and showed better ability of adhesion to Caco-2 cells when assessed for competition with E. coli ATCC 11229 compared to low EPS-producing B2. This investigation showed that EPS production could be affected or be involved in the viability, adherence and competition of L. delbrueckii subsp. bulgaricus strains and support the potential of B3 strain for development of new probiotic products.

Characterization of ESBL-producing Escherichia coli and Klebsiella pneumoniae strains isolated from urine of nonhospitalized patients in the Zagreb region

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Branka Bedenić,

2010-02-01

Full Text Available Aim To determine the prevalence of ESBL-producing Escherichia coli and Klebsiella pneumoniae strains isolated from urine of nonhospitalized patients during a three-year period, to determine their antibiotic susceptibility, investigate the transfer of ESBL genes with cotransfer of resistance and to characterize isolated beta-lactamases. Methods Antimicrobial susceptibility was determined by disk diffusion and broth microdilution methods. The double-disk test was used for ESBL detection. Transfer of resistance was performed by broth mating method and characterization of isolated beta-lactamases by polymerase chain reaction. Results The prevalence of ESBL-producing E. coli was 1.5% and of K. pneumoniae 4.1% with its different distribution according to patients`age and gender. ESBL-producing K. pneumoniae showed high resistance rates to aminoglycosides, cotrimoxazole, nitrofurantoin and quinolones while ESBL-producing E. coli isolates, with exception of high aminoglycoside resistance, showed low resistance rates to other antibiotics. Successful conjugation of ESBL genes was obtained with 25% E. coli and 76.2% K. pneumoniae strains. Comparing to E. coli, K. pneumoniae strains showed higher rates of aminoglycosideand cotrimoxazole resistance cotransfer. Beta-lactamases of investigated strains belonged to TEM, SHV and CTX-M families.Conclusion The existence of multiple-resistant ESBL-producing E. coli and K. pneumoniae strains was confirmed in observed outpatient population. ESBL-producing K. pneumoniae isolates, in contrast toESBL-producing E. coli, showed higher resistance rates to non-beta-lactam antibiotics, probably caused by cotransfer of resistance genes located on the same plasmid as ESBL genes. It is important to monitor the prevalence of such strains and their possible spreading in the outpatient population of the Zagreb region

Olsenella scatoligenes sp. nov., a 3-methylindole- (skatole) and 4-methylphenol- (p-cresol) producing bacterium isolated from pig faeces

DEFF Research Database (Denmark)

Li, Xiaoqiong; Jensen, Rikke Lassen; Højberg, Ole

2015-01-01

Strain SK9K4T, which is a strictly anaerobic, non-motile, non-sporulating, Gram-stain-positive, saccharolytic coccobacillus, was isolated from pig faeces. SK9K4T metabolized indol-3-acetic acid to 3-methylindole (skatole), which is the main contributor to boar taint; it also produced 4-methylphenol......+C content was 62.1 mol% and the major cellular fatty acids (constituting .10% of the total) were C14 : 0 and C18 : 1v9c. The major end product of glucose fermentation was lactic acid, with minor amounts of acetic acid and formic acid; no H2 was produced. Discrepancies in the fatty acid profiles, the MALDI...... (p-cresol) from p-hydroxyphenylacetic acid. Phylogenetic analyses, based on 16S rRNA gene sequences, revealed that the isolate represented a new lineage within the genus Olsenella of the family Atopobiaceae. Strain SK9K4T was most closely related to the type strains of the three species of the genus...

Exploring the Saccharomyces cerevisiae Volatile Metabolome: Indigenous versus Commercial Strains

Science.gov (United States)

Alves, Zélia; Melo, André; Figueiredo, Ana Raquel; Coimbra, Manuel A.; Gomes, Ana C.; Rocha, Sílvia M.

2015-01-01

Winemaking is a highly industrialized process and a number of commercial Saccharomyces cerevisiae strains are used around the world, neglecting the diversity of native yeast strains that are responsible for the production of wines peculiar flavours. The aim of this study was to in-depth establish the S. cerevisiae volatile metabolome and to assess inter-strains variability. To fulfill this objective, two indigenous strains (BT2652 and BT2453 isolated from spontaneous fermentation of grapes collected in Bairrada Appellation, Portugal) and two commercial strains (CSc1 and CSc2) S. cerevisiae were analysed using a methodology based on advanced multidimensional gas chromatography (HS-SPME/GC×GC-ToFMS) tandem with multivariate analysis. A total of 257 volatile metabolites were identified, distributed over the chemical families of acetals, acids, alcohols, aldehydes, ketones, terpenic compounds, esters, ethers, furan-type compounds, hydrocarbons, pyrans, pyrazines and S-compounds. Some of these families are related with metabolic pathways of amino acid, carbohydrate and fatty acid metabolism as well as mono and sesquiterpenic biosynthesis. Principal Component Analysis (PCA) was used with a dataset comprising all variables (257 volatile components), and a distinction was observed between commercial and indigenous strains, which suggests inter-strains variability. In a second step, a subset containing esters and terpenic compounds (C10 and C15), metabolites of particular relevance to wine aroma, was also analysed using PCA. The terpenic and ester profiles express the strains variability and their potential contribution to the wine aromas, specially the BT2453, which produced the higher terpenic content. This research contributes to understand the metabolic diversity of indigenous wine microflora versus commercial strains and achieved knowledge that may be further exploited to produce wines with peculiar aroma properties. PMID:26600152

Lignocellulose-Adapted Endo-Cellulase Producing Streptomyces Strains for Bioconversion of Cellulose-Based Materials.

Science.gov (United States)

Ventorino, Valeria; Ionata, Elena; Birolo, Leila; Montella, Salvatore; Marcolongo, Loredana; de Chiaro, Addolorata; Espresso, Francesco; Faraco, Vincenza; Pepe, Olimpia

2016-01-01

Twenty-four Actinobacteria strains, isolated from Arundo donax, Eucalyptus camaldulensis and Populus nigra biomass during natural biodegradation and with potential enzymatic activities specific for the degradation of lignocellulosic materials, were identified by a polyphasic approach. All strains belonged to the genus Streptomyces ( S .) and in particular, the most highly represented species was Streptomyces argenteolus representing 50% of strains, while 8 strains were identified as Streptomyces flavogriseus (synonym S. flavovirens ) and Streptomyces fimicarius (synonyms Streptomyces acrimycini, Streptomyces baarnensis, Streptomyces caviscabies , and Streptomyces flavofuscus ), and the other four strains belonged to the species Streptomyces drozdowiczii, Streptomyces rubrogriseus, Streptomyces albolongus , and Streptomyces ambofaciens . Moreover, all Streptomyces strains, tested for endo and exo-cellulase, cellobiase, xylanase, pectinase, ligninase, peroxidase, and laccase activities using qualitative and semi-quantitative methods on solid growth medium, exhibited multiple enzymatic activities (from three to six). The 24 strains were further screened for endo-cellulase activity in liquid growth medium and the four best endo-cellulase producers ( S. argenteolus AE58P, S. argenteolus AE710A, S. argenteolus AE82P, and S. argenteolus AP51A) were subjected to partial characterization and their enzymatic crude extracts adopted to perform saccharification experiments on A. donax pretreated biomass. The degree of cellulose and xylan hydrolysis was evaluated by determining the kinetics of glucose and xylose release during 72 h incubation at 50°C from the pretreated biomass in the presence of cellulose degrading enzymes (cellulase and β-glucosidase) and xylan related activities (xylanase and β-xylosidase). The experiments were carried out utilizing the endo-cellulase activities from the selected S. argenteolus strains supplemented with commercial β-gucosidase and

Complete Genome Sequence of a thermotolerant sporogenic lactic acid bacterium, Bacillus coagulans strain 36D1

Energy Technology Data Exchange (ETDEWEB)

Xie, Gary [Los Alamos National Laboratory (LANL); Dalin, Eileen [U.S. Department of Energy, Joint Genome Institute; Tice, Hope [U.S. Department of Energy, Joint Genome Institute; Chertkov, Olga [Los Alamos National Laboratory (LANL); Land, Miriam L [ORNL

2011-01-01

Bacillus coagulans is a ubiquitous soil bacterium that grows at 50-55 C and pH 5.0 and fer-ments various sugars that constitute plant biomass to L (+)-lactic acid. The ability of this sporogenic lactic acid bacterium to grow at 50-55 C and pH 5.0 makes this organism an attractive microbial biocatalyst for production of optically pure lactic acid at industrial scale not only from glucose derived from cellulose but also from xylose, a major constituent of hemi-cellulose. This bacterium is also considered as a potential probiotic. Complete genome squence of a representative strain, B. coagulans strain 36D1, is presented and discussed.

Proteomics analysis of high lipid-producing strain Mucor circinelloides WJ11: an explanation for the mechanism of lipid accumulation at the proteomic level.

Science.gov (United States)

Tang, Xin; Zan, Xinyi; Zhao, Lina; Chen, Haiqin; Chen, Yong Q; Chen, Wei; Song, Yuanda; Ratledge, Colin

2016-02-11

The oleaginous fungus, Mucor circinelloides, is attracting considerable interest as it produces oil rich in γ-linolenic acid. Nitrogen (N) deficiency is a common strategy to trigger the lipid accumulation in oleaginous microorganisms. Although a simple pathway from N depletion in the medium to lipid accumulation has been elucidated at the enzymatic level, global changes at protein levels upon N depletion have not been investigated. In this study, we have systematically analyzed the changes at the levels of protein expression in M. circinelloides WJ11, a high lipid-producing strain (36 %, lipid/cell dry weight), during lipid accumulation. Proteomic analysis demonstrated that N depletion increased the expression of glutamine synthetase, involved in ammonia assimilation, for the supply of cellular nitrogen but decreased the metabolism of amino acids. Upon N deficiency, many proteins (e.g., fructose-bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, enolase, pyruvate kinase) involved in glycolytic pathway were up-regulated while proteins involved in the tricarboxylic acid cycle (e.g., isocitrate dehydrogenase, succinyl-CoA ligase, succinate dehydrogenase, fumarate hydratase) were down-regulated, indicating this activity was retarded thereby leading to a greater flux of carbon into fatty acid biosynthesis. Moreover, glucose-6-phosphate dehydrogenase, transaldolase and transketolase, which participate in the pentose phosphate pathway, were up-regulated, leading to the increased production of NADPH, the reducing power for fatty acid biosynthesis. Furthermore, protein and nucleic acid metabolism were down-regulated and some proteins involved in energy metabolism, signal transduction, molecular chaperone and redox homeostasis were up-regulated upon N depletion, which may be the cellular response to the stress produced by the onset of N deficiency. N limitation increased those expressions of the proteins involved in ammonia assimilation but decreased that

Enhanced D-lactic acid production from renewable resources using engineered Lactobacillus plantarum.

Science.gov (United States)

Zhang, Yixing; Vadlani, Praveen V; Kumar, Amit; Hardwidge, Philip R; Govind, Revathi; Tanaka, Tsutomu; Kondo, Akihiko

2016-01-01

D-lactic acid is used as a monomer in the production of poly-D-lactic acid (PDLA), which is used to form heat-resistant stereocomplex poly-lactic acid. To produce cost-effective D-lactic acid by using all sugars derived from biomass efficiently, xylose-assimilating genes encoding xylose isomerase and xylulokinase were cloned into an L-lactate-deficient strain, Lactobacillus plantarum. The resulting recombinant strain, namely L. plantarum NCIMB 8826 ∆ldhL1-pLEM-xylAB, was able to produce D-lactic acid (at optical purity >99 %) from xylose at a yield of 0.53 g g(-1). Simultaneous utilization of glucose and xylose to produce D-lactic acid was also achieved by this strain, and 47.2 g L(-1) of D-lactic acid was produced from 37.5 g L(-1) glucose and 19.7 g L(-1) xylose. Corn stover and soybean meal extract (SBME) were evaluated as cost-effective medium components for D-lactic acid production. Optimization of medium composition using response surface methodology resulted in 30 % reduction in enzyme loading and 70 % reduction in peptone concentration. In addition, we successfully demonstrated D-lactic acid fermentation from corn stover and SBME in a fed-batch fermentation, which yielded 61.4 g L(-1) D-lactic acid with an overall yield of 0.77 g g(-1). All these approaches are geared to attaining high D-lactic acid production from biomass sugars to produce low-cost, highly thermostable biodegradable plastics.

Effectiveness of 5-Pyrrolidone-2-carboxylic Acid and Copper Sulfate Pentahydrate Association against Drug Resistant Staphylococcus Strains.

Science.gov (United States)

Governa, Paolo; Miraldi, Elisabetta; De Fina, Gianna; Biagi, Marco

2016-04-01

Bacterial resistance is an ongoing challenge for pharmacotherapy and pharmaceutical chemistry. Staphylococcus aureus is the bacterial species which makes it most difficult to treat skin and soft tissue infections and it is seen in thousands of hospitalization cases each year. Severe but often underrated infectious diseases, such as complicated nasal infections, are primarily caused by MRSA and S. epidermidis too. With the aim of studying new drugs with antimicrobial activity and effectiveness on drug resistant Staphylococcus strains, our attention in this study was drawn on the activity of a new association between two natural products: 5-pyrrolidone-2-carboxylic acid (PCA), naturally produced by certain Lactobacillus species, and copper sulfate pentahydrate (CS). The antimicrobial susceptibility test was conducted taking into account 12 different Staphylococcus strains, comprising 6 clinical isolates and 6 resistant strains. PCA 4%, w/w, and CS 0.002%, w/w, association in distilled water solution was found to have bactericidal activity against all tested strains. Antimicrobial kinetics highlighted that PCA 4%, w/w, and CS 0.002% association could reduce by 5 log10 viable bacterial counts of MRSA and oxacillin resistant S. epidennidis in less than 5 and 3 minutes respectively. Microscopic investigations suggest a cell wall targeting mechanism of action. Being very safe and highly tolerated, the natural product PCA and CS association proved to be a promising antimicrobial agent to treat Staphylococcus related infections.

Improved production, purification, and characterization of biosurfactants produced by Serratia marcescens SM3 and its isogenic SMRG-5 strain.

Science.gov (United States)

Rosas-Galván, Nashbly Sarela; Martínez-Morales, Fernando; Marquina-Bahena, Silvia; Tinoco-Valencia, Raunel; Serrano-Carreón, Leobardo; Bertrand, Brandt; León-Rodríguez, Renato; Guzmán-Aparicio, Josefina; Alvaréz-Berber, Laura; Trejo-Hernández, María R

2018-02-19

In this study, the biosurfactants (Bs) production of two Serratia marcescens strains (SM3 and its isogenic SMRG-5 strain) was improved and the tenso-active agents were purified and characterized. A 2 3 factorial design was used to evaluate the effect of nitrogen and carbon sources on the surface tension (ST) reduction and emulsion index (EI 24 ) of the produced Bs. Optimum Bs production by SM3 was achieved at high concentrations of carbon and nitrogen, reducing ST to 26.5 ± 0.28 dynes/cm, with an EI 24 of 79.9 ± 0.2%. Meanwhile, the best results for SMRG-5 were obtained at low concentrations, reducing the ST to 25.2 ± 0.2 dynes/cm, with an EI 24 of 89.7 ± 0.28%. The optimal conditions for Bs production were scaled up in a 2-L reactor, yielding 4.8 and 5.2 g/L for SM3 and SMRG-5, respectively. Gas Chromatography-Mass Spectrometry (GC-MS) analysis revealed the presence of two different lipopeptides (hidrofobic fractions: octadecanoic and hexadecanoic acid for SM3 and SMRG5, respectively). Both strains were capable of benzo [a] pyrene removal (59% after 72 H of culture). © 2018 International Union of Biochemistry and Molecular Biology, Inc.

[Co-occurence of indol-producing bacterial strains in the vagina of women infected with Chlamydia trachomatis].

Science.gov (United States)

Romanik, Małgorzata; Martirosian, Gayane; Wojciechowska-Wieja, Anna; Cieślik, Katarzyna; Kaźmierczak, Wojciech

2007-08-01

The aim of this study was to determine if cervicitis, caused by Chlamydia trachomatis (C. trachomatis), has an influence on the frequency of occurrence of selected aerobic and anaerobic bacterial strains, connected with etiology of aerobic vaginitis (AV) and bacterial vaginosis (BV). Indole-producing bacteria have received particular attention due to their possibly inductive role in chronic cervicitis caused by C. trachomatis. The swabs from vagina and cervical canal have been obtained from 122 women (aged 18-40). The presence of C. trachomatis antigen had been detected and diagnosed with the help of direct immunofluorescence, BV with Amesl and Nugent criteria, whereas the AV with Donders criteria. The identification of the bacterial strains isolated from vagina has been performed according to classical microbiological diagnostics. Disruption of vaginal microflora (4-10 in Nugent score) was determined in 11,5% of observed women. AV was diagnosed in 4.5% women with chlamydial cervicitis, BV was diagnosed in 10.9% and 5.45% of these women, on the basis of Amsel and Nugent criteria respectively. Indole-producing bacterial strains connected with BV and AV (Peptostreptococcus anaerobius, Propionibacterium acnes, Escherichia coli) have been isolated significantly more often from vagina of women infected with C trachomatis (p = 0.0405, chi2 = 4.20) and these findings confirm co-importance of indole-producing bacterial strains in cervicitis caused by C trachomatis .

Branched-chain fatty acid biosynthesis in a branched-chain amino acid aminotransferase mutant of Staphylococcus carnosus

DEFF Research Database (Denmark)

Beck, Hans Christian

2005-01-01

Fatty acid biosynthesis by a mutant strain of Staphylococcus carnosus deficient in branched-chain amino acid aminotransferase (IlvE) activity was analysed. This mutant was unable to produce the appropriate branched-chain alpha-ketoacid precursors for branched-chain fatty acid biosynthesis from...... in rich medium and growth in defined medium supplemented with 2-methylpropanoic acid lead to extensive alteration of the fatty acid composition in the cell membrane. In rich medium, a change from 51.7% to 17.1% anteiso-C15:0, and from 3.6% to 33.9% iso-C14:0 fatty acids as compared to the wild-type strain...... for 2-methylpropanoic acid production, revealing that the IlvE protein plays an important, but not essential role in the biosynthesis of branched-chain fatty acids and secondary metabolites in S. carnosus....

Structural identification of lipopeptide biosurfactants produced by Bacillus subtilis strains grown on the media obtained from renewable natural resources.

Science.gov (United States)

Paraszkiewicz, Katarzyna; Bernat, Przemysław; Kuśmierska, Anna; Chojniak, Joanna; Płaza, Grażyna

2018-03-01

The aim of the study was to identify and characterize lipopeptide (LP) biosurfactants produced by two Bacillus subtilis strains (KP7 and I'-1a) grown on various media prepared from renewable natural resources: two different brewery wastewaters (BW#4 and BW#6), 2% beet molasses (M), apple peels extract (APE) supplemented with 0.25% of yeast extract (YE) or 0.25% peptone (P), and similarly supplemented carrot peels extract (CPE). In all used media both strains retained their individual LP production signature characterized by surfactin and iturin overproduction exhibited by KP7 and I'-1a strain, respectively. The production level and the structural diversity of synthesized LPs were dependent on the medium composition. In the CPE+YE medium it was higher than the yield obtained in Luria-Bertani (140.6 and 100.3 mg L -1 , respectively). Surfactins were produced by both strains as a mixture of four homologues (C13-C16) with the domination of variant C14. All other broths prepared from renewable resources strongly stimulated the iturin production by I'-1a strain with the exception of BW media. The highest iturin concentration (428.7 mg L -1 ) obtained in the CPE+P culture of I'-1a strain was about seven-fold higher than in LB. In all cultures only iturin A was identified. Among four iturin homologues (C13-16) produced by I'-1a strain, the highest relative contents of C16 variant (70-80%) were calculated for samples obtained from APE+P and CPE+P media. The obtained data indicate that the waste composition has an influence on both the types and amounts of biosurfactants produced by studied B. subtilis strains. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparative Genomic and Phylogenetic Analysis of a Shiga Toxin Producing Shigella sonnei (STSS Strain

Directory of Open Access Journals (Sweden)

Domonkos Sváb

2017-05-01

Full Text Available Shigella strains are important agents of bacillary dysentery, and in recent years Shigella sonnei has emerged as the leading cause of shigellosis in industrialized and rapidly developing countries. More recently, several S. sonnei and Shigella flexneri strains producing Shiga toxin (Stx have been reported from sporadic cases and from an outbreak in America. In the present study we aimed to shed light on the evolution of a recently identified Shiga toxin producing S. sonnei (STSS isolated in Europe. Here we report the first completely assembled whole genome sequence of a multidrug resistant (MDR Stx-producing S. sonnei (STSS clinical strain and reveal its phylogenetic relations. STSS 75/02 proved to be resistant to ampicillin, streptomycin, tetracycline, chloramphenicol, thrimetoprim, and sulfomethoxazol. The genome of STSS 75/02 contains a 4,891,717 nt chromosome and seven plasmids including the 214 kb invasion plasmid (pInv harboring type III secretion system genes and associated effectors. The chromosome harbors 23 prophage regions including the Stx1 converting prophage. The genome carries all virulence determinants necessary for an enteroinvasive lifestyle, as well as the Stx1 encoding gene cluster within an earlier described inducible converting prophage. In silico SNP genotyping of the assembled genome as well as 438 complete or draft S. sonnei genomes downloaded from NCBI GenBank revealed that S. sonnei 75/02 belongs to the more recently diverged global MDR lineage (IIIc. Targeted screening of 1131 next-generation sequencing projects taken from NCBI Short Read Archive of confirms that only a few S. sonnei isolates are Stx positive. Our results suggest that the acquisition of Stx phages could have occurred in different environments as independent events and that multiple horizontal transfers are responsible for the appearance of Stx phages in S. sonnei strains.

Progress of succinic acid production from renewable resources: Metabolic and fermentative strategies.

Science.gov (United States)

Jiang, Min; Ma, Jiangfeng; Wu, Mingke; Liu, Rongming; Liang, Liya; Xin, Fengxue; Zhang, Wenming; Jia, Honghua; Dong, Weiliang

2017-12-01

Succinic acid is a four-carbon dicarboxylic acid, which has attracted much interest due to its abroad usage as a precursor of many industrially important chemicals in the food, chemicals, and pharmaceutical industries. Facing the shortage of crude oil supply and demand of sustainable development, biological production of succinic acid from renewable resources has become a topic of worldwide interest. In recent decades, robust producing strain selection, metabolic engineering of model strains, and process optimization for succinic acid production have been developed. This review provides an overview of succinic acid producers and cultivation technology, highlight some of the successful metabolic engineering approaches. Copyright © 2017 Elsevier Ltd. All rights reserved.