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Sample records for scenedesmus obliquus chlorophyceae

  1. Grazer-induced defense in Scenedesmus obliquus (Chlorophyceae)

    NARCIS (Netherlands)

    Lürling, M.

    2000-01-01

    The non-spiny Scenedesmus obliquus may express considerable phenotypic plasticity in response to changes in their environment. When exposed to chemicals released from the grazer Ceriodaphnia, unicellular S. obliquus populations were rapidly transformed into colonial ones. The morphological response

  2. Extractable substances (anionic surfactants) from membrane filters induce morphological changes in the green alga Scenedesmus obliquus (Chlorophyceae)

    NARCIS (Netherlands)

    Lürling, M.; Beekman, W.

    2002-01-01

    The effect of filtration of medium through different kinds of filters (glass fiber, mixed esters of cellulose and nitrocellulose) on the morphology in the green alga Scenedesmus obliquus was examined. Several compounds potentially released from membrane filters were further investigated, and among

  3. Extractable substances (anionic surfactants) from membrane filters induce morphological changes in the green alga Scenedesmus Obliquus (Chlorophyceae)

    NARCIS (Netherlands)

    Lürling, M.; Beekman, W.

    2002-01-01

    The effect of filtration of medium through different kinds of filters (glass fiber, mixed esters of cellulose and nitrocellulose) on the morphology in the green alga Scenedesmus obliquus was examined. Several compounds potentially released from membrane filters were further investigated, and among

  4. Herbicides interfere with antigrazer defenses in Scenedesmus obliquus.

    Science.gov (United States)

    Zhu, Xuexia; Sun, Yunfei; Zhang, Xingxing; Heng, Hailu; Nan, Haihong; Zhang, Lu; Huang, Yuan; Yang, Zhou

    2016-11-01

    The extensive application of herbicides has led to a serious threat of herbicide contamination to aquatic ecosystem. Herbicide exposure affects aquatic communities not only by exerting toxicity on single species but also by changing interspecific interactions. This study investigated the antigrazer defenses of the common green alga Scenedesmus obliquus against different herbicides [glyphosate, 2,4-dichlorophenoxyacetic acid (2,4-D), and atrazine] at various concentrations (0-2.0 mg L(-1)). In the presence of grazer (Daphnia)-derived cues, S. obliquus populations without herbicides formed high proportions of multicelled (e.g., four- and eight-celled) colonies. This result confirms that S. obliquus exhibits a morphological defense against grazing risk. At the low concentration range of 0.002-0.02 mg L(-1), the three herbicides exerted no influence on the growth and photosynthetic efficiency of S. obliquus, and multicelled colonies showed constant proportions. At the high concentration range of 0.20-2.0 mg L(-1), atrazine significantly inhibited the algal growth and photosynthesis whereas glyphosate or 2,4-D did not. Nonetheless, these levels of glyphosate or 2,4-D remarkably decreased the proportion of multicelled colonies, with reduced numbers of cells per particle in Daphnia filtrate-treated population. No eight-celled colony was formed after treatment with atrazine at 0.20-2.0 mg L(-1) despite the addition of Daphnia filtrate. These results suggest that herbicide exposure impairs antigrazer colonial morphs in phytoplankton although it is not sufficient to hamper algal growth. This phenomenon can increase the risk of predation by herbivores, thereby disrupting the inducible phytoplankton community. Furthermore, the predator-prey interactions between herbivores and phytoplankton can be potentially changed more seriously than previously considered. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Acute and chronic toxic effects of chloramphenicol on Scenedesmus obliquus and Chlorella pyrenoidosa.

    Science.gov (United States)

    Zhang, Wei; Sun, Wenfang; An, Shuai; Xiong, Bang; Lin, Kuangfei; Cui, Xinhong; Guo, Meijin

    2013-08-01

    The acute and chronic toxicological effects of Chloramphenicol (CAP) on Scenedesmus obliquus and Chlorella pyrenoidosa are not well understood. The indoor experiments were carried to observe and analyze the CAP induced changes. Results of the observations have showed that CAP exposure could significantly inhibit the growth of Scenedesmus obliquus in almost all the treated groups, while Chlorella pyrenoidosa exhibited less sensitivity. Chlorophyll-a syntheses of Scenedesmus obliquus were all inhibited by CAP exposure, while Chlorella pyrenoidosa displayed obvious stimulation effect. Catalase (CAT) and Superoxide dismutase (SOD) activities of both algae were promoted in all the treatments. The experimental results indicated that the growth and Chlorophyll-a syntheses of Scenedesmus obliquus were more sensitive in response to CAP exposure than that of Chlorella pyrenoidosa. While for CAT and SOD activities, Chlorella pyrenoidosa showed more susceptible. This research provides a basic understanding of CAP toxicity to aquatic organisms.

  6. Sequence analysis of the its-2 region: a tool to identify strains of Scenedesmus (Chlorophyceae)

    NARCIS (Netherlands)

    Van Hannen, E.J.; Lürling, M.; Van Donk, E.

    2000-01-01

    The genetic distances between several strains of Senedesmus obliquus (Turp,) Kutz,, S, acutus Hortobagyi, and S, naegelii Chod. calculated from ITS-2 sequences were found to be smaller than the genetic distances within other strains of Scenedesmus-that is, in S, acuminatus (Lagerh,) Chod, and S,

  7. Nitrogen budget in Scenedesmus obliquus cultures with artificial wastewater.

    Science.gov (United States)

    Nuñez, V J; Voltolina, D; Nieves, M; Piña, P; Medina, A; Guerrero, M

    2001-06-01

    Semicontinuous cultures of Scenedesmus obliquus in artificial wastewater, recycled into proteins about 33% and 25% of the dissolved nitrogen missing from the medium 24 h after harvesting 50% and 70% of the culture, and replacing the volume harvested with fresh medium. The residual dissolved nitrogen concentrations were 25% and 43% of the initial, respectively, with an imbalance in the mass budget close to 17 and 20 mg N l(-1) d-1. Most or all the nitrogen missing was found in an ammonia trap located at the air vent of the closed cultures, showing that an important role of microalgae in wastewater treatment is that of favouring NH3 stripping due to the photosynthesis-induced pH increases.

  8. Grazer-induced morphological defense in Scenedesmus obliquus is affected by competition against Microcystis aeruginosa.

    Science.gov (United States)

    Zhu, Xuexia; Wang, Jun; Lu, Yichun; Chen, Qinwen; Yang, Zhou

    2015-07-30

    The green alga Scenedesmus is known for its phenotypic plasticity in response to grazing risk. However, the benefits of colony formation induced by infochemicals from zooplankton should come with costs. That is, a tradeoff in benefit-to-cost ratios is likely under complex environmental conditions. In this study, we hypothesized that the coexistence of Scenedesmus and its competitors decreases the formation of anti-grazer colonies in Scenedesmus. Results demonstrated that the presence of a competitor Microcystis aeruginosa inhibited inducible defensive colony formation of Scenedesmus obliquus, and the established defensive colonies negatively affected the competitive ability of S. obliquus. The proportion of induced defensive colonies in cultures was dependent on the relative abundance of competitors. Under low competition intensity, large amount of eight-celled colonies were formed but at the cost of decreased competitive inhibition on M. aeruginosa. By contrast, defensive colony formation of S. obliquus slacked in the presence of high competition intensity to maintain a high displacement rate (competitive ability). In conclusion, S. obliquus exhibited different responses to potential grazing pressure under different intensities of competition, i.e., Scenedesmus morphological response to grazing infochemicals was affected by competition against Microcystis.

  9. "Rational" management of dichlorophenols biodegradation by the microalga Scenedesmus obliquus.

    Science.gov (United States)

    Papazi, Aikaterini; Kotzabasis, Kiriakos

    2013-01-01

    The microalga Scenedesmus obliquus exhibited the ability to biodegrade dichlorophenols (dcps) under specific autotrophic and mixotrophic conditions. According to their biodegradability, the dichlorophenols used can be separated into three distinct groups. Group I (2,4-dcp and 2,6 dcp - no meta-substitution) consisted of quite easily degraded dichlorophenols, since both chloride substituents are in less energetically demanding positions. Group II (2,3-dcp, 2,5-dcp and 3,4-dcp - one meta-chloride) was less susceptible to biodegradation, since one of the two substituents, the meta one, required higher energy for C-Cl-bond cleavage. Group III (3,5-dcp - two meta-chlorides) could not be biodegraded, since both chlorides possessed the most energy demanding positions. In general, when the dcp-toxicity exceeded a certain threshold, the microalga increased the energy offered for biodegradation and decreased the energy invested for biomass production. As a result, the biodegradation per cell volume of group II (higher toxicity) was higher, than group I (lower toxicity) and the biodegradation of dichlorophenols (higher toxicity) was higher than the corresponding monochlorophenols (lower toxicity). The participation of the photosynthetic apparatus and the respiratory mechanism of microalga to biodegrade the group I and the group II, highlighted different bioenergetic strategies for optimal management of the balance between dcp-toxicity, dcp-biodegradability and culture growth. Additionally, we took into consideration the possibility that the intermediates of each dcp-biodegradation pathway could influence differently the whole biodegradation procedures. For this reason, we tested all possible combinations of phenolic intermediates to check cometabolic interactions. The present contribution bring out the possibility of microalgae to operate as "smart" bioenergetic "machines", that have the ability to continuously "calculate" the energy reserves and "use" the most energetically

  10. Biodiesel Production by the Green Microalga Scenedesmus obliquus in a Recirculatory Aquaculture System

    Science.gov (United States)

    Mandal, Shovon

    2012-01-01

    Biodiesel production was examined with Scenedesmus obliquus in a recirculatory aquaculture system with fish pond discharge and poultry litter to couple with waste treatment. Lipid productivity of 14,400 liter ha−1 year−1 was projected with 11 cultivation cycles per year. The fuel properties of the biodiesel produced adhered to Indian and international standards. PMID:22660702

  11. Green compressed fluid technologies for downstream processing of Scenedesmus obliquus in a biorefinery approach

    NARCIS (Netherlands)

    Gilbert-López, Bienvenida; Mendiola, José A.; Broek, van den Lambertus A.M.; Houweling-Tan, Bwee; Sijtsma, Lolke; Cifuentes, Alejandro; Herrero, Miguel; Ibáñez, Elena

    2017-01-01

    The fractionation of algae biomass in several high-value compounds that can be used as ingredients in other applications sets the basis of the algae biorefinery approach. The present study aimed at the extraction and fractionation of bioactive compounds from the microalga Scenedesmus obliquus, by

  12. Low temperature and Daphnia-associated infochemicals promote colony formation of Scenedesmus obliquus and its harvesting.

    Science.gov (United States)

    Zhu, Xuexia; Yang, Jingwen; Zhang, Xingxing; Zhang, Lu; Wang, Xiaojun; Huang, Yuan; Yang, Zhou

    2017-01-01

    To explore the combined effects of temperature and Daphnia-associated infochemicals on colony formation of Scenedesmus obliquus to faciliate harvesting the algal biomass. A three-parameter modified Gaussian model fitted the changes of the number of cells per particle in S. obliquus induced by Daphnia culture filtrate well under any temperature. Decreases in temperature enhanced the induced-colony formation of Scenedesmus. The maximum colony size at 15-25 °C was significantly larger than those at 30-35 °C. An additional 1 or 2 days at low temperature was needed to reach the maximum colony size, which indicates the best harvest time for algal biomass. Induced-colony formation of Scenedesmus by Daphnia culture filtrate at 15-25 °C is recommended to settle algal cells. This condition facilitates harvesting the biomass.

  13. Supercritical fluid extraction and characterization of lipids from algae Scenedesmus obliquus

    Science.gov (United States)

    Choi, K. J.; Nakhost, Z.; Krukonis, V. J.; Karel, M.

    1987-01-01

    Lipids were extracted from a protein concentrate of green algae (Scenedesmus obliquus), using a one-step supercritical carbon dioxide extraction procedure in presence of ethanol as an entrainer, and were characterized. The compositions of neutral lipids, glycolipids, and phospholipids, separated into individual components by column, thin-layer, and gas-liquid chromatography procedures, are presented. Fatty acid composition patterns indicated that the major fatty acids were 16:0, 16:1, 16:2, 16:3, 16:4, 18:1, 18:2, and 18:3. The lipids of S. obliquus were found to contain relatively high concentrations of polyunsaturated fatty acids and essential fatty acids.

  14. Factors Affecting Infection of Scenedesmus obliquus by a Chytridium sp. in Sewage Oxidation Ponds.

    Science.gov (United States)

    Abeliovich, A; Dikbuck, S

    1977-12-01

    In a high-rate oxidation pond, 0.1 to 1.0% of the algal population of Scenedesmus obliquus was found to be infected by a chytrid. When suitable conditions developed, these infections burst into massive epidemics that killed most of the algae. The major factors triggering massive infections were optimal oxygen concentration and low concentrations of potassium and magnesium cations. The fungicide Benomyl was effective in preventing infection at a concentration of 1 mg/liter.

  15. Nitrogen source, an important determinant of fatty acid accumulation and profile in scenedesmus obliquus

    OpenAIRE

    Yılancıoğlu, Kaan; Yilancioglu, Kaan; Tekin, H. O.; Çetiner, Selim; Cetiner, Selim

    2016-01-01

    The potential of algae-based fuel technologies for manufacturing renewable biofuels has been attracting interest from the scientific community. Biomass productivity and cellular lipid content are important parameters affecting the feasibility of using algae oil for biodiesel production. This study compares utilization of NaNO3, NH4Cland urea as different nitrogen sources in terms of their effects on biomass productivity, fatty acid profile and accumulation in Scenedesmus obliquus. Cell...

  16. Acute and chronic toxic effects of bisphenol A on Chlorella pyrenoidosa and Scenedesmus obliquus.

    Science.gov (United States)

    Zhang, Wei; Xiong, Bang; Sun, Wen-Fang; An, Shuai; Lin, Kuang-Fei; Guo, Mei-Jin; Cui, Xin-Hong

    2014-06-01

    The acute and chronic toxic effects of Bisphenol A (BPA) on Chlorella pyrenoidosa (C. pyrenoidosa) and Scenedesmus obliquus (S. obliquus) were not well understood. The indoor experiments were carried out to observe and analyze the BPA-induced changes. Results of the observations showed that in acute tests BPA could significantly inhibit the growth of both algae, whereas chronic exposure hardly displayed similar trend. Superoxide dismutase (SOD) and Catalase (CAT) activities of both algae were promoted in all the treatments. Chlorophyll a synthesis of the two algae exhibited similar inhibitory trend in short-term treatments, and in chronic tests C. pyrenoidosa hardly resulted in visible influence, whereas in contrast, dose-dependent inhibitory effects of S. obliquus could be clearly observed. The experimental results indicated that the growth and Chlorophyll a syntheses of S.obliquus were more sensitive in response to BPA than that of C. pyrenoidosa, whereas for SOD andCAT activities, C. pyrenoidosa was more susceptible. This research provides a basic understanding of BPA toxicity to aquatic organisms. Copyright © 2012 Wiley Periodicals, Inc.

  17. Comparison of different physiological parameter responses in Lemna minor and Scenedesmus obliquus exposed to herbicide flumioxazin

    Energy Technology Data Exchange (ETDEWEB)

    Geoffroy, Laure; Frankart, Cecile; Eullaffroy, Philippe

    2004-09-01

    The sensitivity of different physiological parameters in Scenedesmus obliquus and Lemna minor exposed to herbicide (flumioxazin) was investigated to indicate the most convenient and sensitive parameter. To assess toxicity of flumioxazin, we used a panel of biomarkers: pigment contents, chlorophyll fluorescence parameters and antioxidative enzyme activities. Algae and duckweed were exposed to 48-h IC{sub 50} for growth rate. In L. minor, the sensitivity of the parameters was as follows: Q{sub N}>Oxygen emission>PHIs{sub PSII}>Q{sub P}>PHI{sub PSII}>CAT, GR>Pigment>APO>Growth. For S. obliquus, this ranking was as follows: CAT>Oxygen emission>Q{sub P}>APO>GR>Pigment>PHIs{sub PSII}>Growth>PHI{sub PSII}>Q{sub N} (from the greatest to the least sensitive). The results demonstrated that the observed toxicity is related not only to interspecific variations but also to the selected parameter.

  18. Graphene oxide alleviates the ecotoxicity of copper on the freshwater microalga Scenedesmus obliquus.

    Science.gov (United States)

    Hu, Changwei; Hu, Naitao; Li, Xiuling; Zhao, Yongjun

    2016-10-01

    The extensive industrial application of graphene oxide (GO), has increased its exposure risk to various aquatic organisms and its potential to affect the toxicity of other environmental pollutants. In this study, we investigated the combined toxicity of GO and copper on the freshwater microalga Scenedesmus obliquus, using the MIXTOX model. The effects of low concentration (1mg/L) exposure to GO were investigated with environmentally relevant concentrations of copper by using a 12-d subacute toxicity test, with pre- and post-GO treatment. Results showed that there were significant antagonistic effects between GO and copper on S. obliquus, and GO was found to reduce ecotoxicity of copper even at low and environmentally relevant concentrations (1mg/L). Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Produccion de Biomasa de Scenedesmus Obliquus en diferentes medios de cultivo.

    OpenAIRE

    Martínez, V.; Pellón, A.; Pérez, E; O. Correa; Escobedo, R.; Y. Madruga; A. Oña; Arencibia, R.

    2005-01-01

    Los nutrientes son factores fundamentales que afectan el rendimiento de los cultivos de microalgas, de ahí la importancia de llevar a cabo estudios a escala de laboratorio con cepas de interés científico y comercial. El objetivo del trabajo fue investigar la producción de biomasa de Scenedesmus obliquus en diferentes medios de cultivo. Se utilizaron dos reactores tipo columnas de 2 L de capacidad empleando medio Extracto de Suelo, y medio Albañal Sintético respectivamente, a los cuales se les...

  20. The ghost of herbivory past: slow defence relaxation in the chlorophyte Scenedesmus obliquus

    Directory of Open Access Journals (Sweden)

    Jacobus VIJVERBERG

    2009-08-01

    Full Text Available The freshwater chlorophyte Scenedesmus obliquus (Turpin Kützing produces colonies as an inducible defence against herbivores. We investigated the dynamics of Scenedesmus colony formation and disintegration in response to the density of the herbivorous rotifer Brachionus calyciflorus in large-scale mesocosms. Additional bioassays were performed to investigate Scenedesmus colony disintegration under different light regimes. In the mesocosm experiment, colony formation took place rapidly, but relaxation towards the initial size took relatively long (>10 d after cessation of herbivory. In the bioassays, in the absence of infochemicals, colonies disintegrated almost immediately in the dark (1-1.5 d, within 4 d under a photoperiod of 16:8 (L:D and between 8 and 12 days under full light. Colony disintegration times in the mesocosm experiment were substantially longer as compared to treatments with the same photoperiod (L:D 16:8 in the bioassays. So after a peak of herbivory, the 'ghost of herbivory past', i.e. the remaining infochemicals, may continue to induce colony formation, causing an additional lengthening of colony disintegration times and associated fitness costs (higher sedimentation loss rates. This indicates that costs of colony formation are not only important during the induction phase, but may be even more important during the relaxation phase. We compared these sedimentation costs to the costs of herbivory for differently sized Scenedesmus, and found a clear trade-off pattern for these costs.

  1. Wastewater treatment and biodiesel production by Scenedesmus obliquus in a two-stage cultivation process.

    Science.gov (United States)

    Álvarez-Díaz, P D; Ruiz, J; Arbib, Z; Barragán, J; Garrido-Pérez, M C; Perales, J A

    2015-04-01

    The microalga Scenedesmus obliquus was cultured in two cultivation stages: (1) in batch with real wastewater; (2) maintaining the stationary phase with different conditions of CO2, light and salinity according to a factorial design in order to improve the lipid content. The presence of the three factors increased lipid content from 35.8% to 49% at the end of the second stage; CO2 presence presented the highest direct effect increasing lipid content followed by light presence and salt presence. The ω-3 fatty acids content increased with CO2 and light presence acting in isolation, nevertheless, when both factors acted together the interaction effect was negative. The ω-3 eicosapentaenoic acid content of the oil from S. obliquus slightly exceeded the 1% maximum to be used as biodiesel source (EU normative). Therefore, it is suggested the blend with other oils or the selective extraction of the ω-3 fatty acids from S. obliquus oil. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Optimization of aeration for biodiesel production by Scenedesmus obliquus grown in municipal wastewater.

    Science.gov (United States)

    Han, Song-Fang; Jin, Wenbiao; Tu, Renjie; Abomohra, Abd El-Fatah; Wang, Zhi-Han

    2016-07-01

    Despite the significant breakthroughs in research on microalgae as a feedstock for biodiesel, its production cost is still much higher than that of fossil diesel. One possible solution to overcome this problem is to optimize algal growth and lipid production in wastewater. The present study examines the optimization of pretreatment of municipal wastewater and aeration conditions in order to enhance the lipid productivity of Scenedesmus obliquus. Results showed that no significant differences were recorded in lipid productivity of S. obliquus grown in primary settled or sterilized municipal wastewater; however, ultrasound pretreatment of wastewater significantly decreased the lipid production. Whereas, aeration rates of 0.2 vvm significantly increased lipid content by 51 %, with respect to the non-aerated culture, which resulted in maximum lipid productivity (32.5 mg L(-1) day(-1)). Furthermore, aeration enrichment by 2 % CO2 resulted in increase of lipid productivity by 46 % over the CO2 non-enriched aerated culture. Fatty acid profile showed that optimized aeration significantly enhanced monounsaturated fatty acid production, composed mainly of C18:1, by 1.8 times over the non-aerated S. obliquus culture with insignificant changes in polyunsaturated fatty acid proportion; suggesting better biodiesel characteristics for the optimized culture.

  3. Effect of food wastewater on biomass production by a green microalga Scenedesmus obliquus for bioenergy generation.

    Science.gov (United States)

    Ji, Min-Kyu; Yun, Hyun-Shik; Park, Sanghyun; Lee, Hongkyun; Park, Young-Tae; Bae, Sunyoung; Ham, Jungyeob; Choi, Jaeyoung

    2015-03-01

    Effect of food wastewater (FW) on the biomass, lipid and carbohydrate production by a green microalga Scenedesmus obliquus cultivated in Bold's Basal Medium (BBM) was investigated. Different dilution ratios (0.5-10%) of BBM either with FW or salt solution (NaCl) or sea water (SW) were evaluated. S. obliquus showed the highest growth (0.41 g L(-1)), lipid productivity (13.3 mg L(-1) day L(-1)), carbohydrate productivity (14.7 mg L(-1) day L(-1)) and nutrient removal (38.9 mg TN L(-1) and 12.1 mg TP L(-1)) with 1% FW after 6 days of cultivation. The FW promoted algal autoflocculation due to formation of inorganic precipitates at an alkali pH. Fatty acid methyl ester analysis revealed that the palmitic and oleic acid contents were increased up to 8% with FW. Application of FW improved the growth, lipid/carbohydrate productivity and biomass recovery efficiency of S. obliquus, which can be exploited for cost effective production of microalgae biomass. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Toxicity evaluation of pharmaceutical wastewaters using the alga Scenedesmus obliquus and the bacterium Vibrio fischeri.

    Science.gov (United States)

    Yu, Xin; Zuo, Jiane; Tang, Xinyao; Li, Ruixia; Li, Zaixing; Zhang, Fei

    2014-02-15

    The toxicity of pharmaceutical wastewaters has recently been the focus of the public in China. This study aimed to evaluate the conventional pollution parameters and toxicities of different raw and treated pharmaceutical wastewaters to algae Scenedesmus obliquus and bacteria Vibrio fischeri. Wastewater samples were collected from 16 pharmaceutical wastewater treatment plants in China. The results of the conventional parameters analysis indicated that the total suspended solids, chemical oxygen demand (COD), ammonia (NH3-N), and total phosphorus (TP) were largely removed after treatment. Pharmaceutical effluents were mainly polluted with organics and phosphorus as indicated by the average COD (388 mg/L) and TP (3.16 mg/L) concentrations. The toxicity test results indicated that the influent samples were toxic to both test species. Although the toxicities could be remarkably reduced after treatment, 10 out of the 16 effluent samples exceeded the acute toxicity discharge limit of the Chinese national standards. Spearman rank correlation coefficients indicated a significantly positive correlation between the toxicity values of S. obliquus and V. fischeri. Compared with S. obliquus, V. fischeri detected more pharmaceutical effluent samples with toxicities. Meanwhile, the toxicity indicators were significantly and positively correlated with the COD and NH3-N concentrations based on a Spearman rank correlation analysis. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Utilization of xylose as a carbon source for mixotrophic growth of Scenedesmus obliquus.

    Science.gov (United States)

    Yang, Suling; Liu, Guijun; Meng, Youting; Wang, Ping; Zhou, Sijing; Shang, Hongzhong

    2014-11-01

    Mixotrophic cultivation is one potential mode for microalgae production, and an economically acceptable and environmentally sustainable organic carbon source is essential. The potential use of xylose for culturing Scenedesmus obliquus in a mixotrophic mode and physiological features of xylose-grown S. obliquus were studied. S. obliquus had a certain xylose tolerance, and was capable of utilizing xylose for growth. At a xylose concentration of 4gL(-1), the maximal cell density was 2.2gL(-1), being 2.9-fold of that under photoautotrophic condition and arriving to the level of mixotrophic growth using 4gL(-1) glucose. No changes in cellular morphology of the cells grown with or without xylose were detected. Fluorescence emission from photosystem II (PS II) relative to photosystem I (PS I) was decreased in mixotrophic cells, implying that the PSII activity was decreased. The biomass lipid content was enhanced and carbohydrate concentration was decreased, in relation to photoautotrophic controls. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Isothermal and non-isothermal torrefaction characteristics and kinetics of microalga Scenedesmus obliquus CNW-N.

    Science.gov (United States)

    Chen, Wei-Hsin; Wu, Zih-Ying; Chang, Jo-Shu

    2014-03-01

    Isothermal and non-isothermal torrefaction characteristics and kinetics of microalga Scenedesmus obliquus (S. obliquus) CNW-N are studied using thermogravimetric analysis. The pyrolysis of S. obliquus CNW-N with increasing temperature is characterized by four-stage decomposition. Depending on the torrefaction temperature, light, mild, and severe torrefaction from the weight loss and the maximum decomposition rate of the microalga can be classified. Under the same average temperature and torrefaction duration, non-isothermal torrefaction gives more severe pretreatment than the isothermal one. Increasing the heating rate of non-isothermal torrefaction also intensifies the pretreatment severity. Therefore, microalgae can be torrefied via non-isothermal torrefaction in a shorter time under the same pretreatment extent. The atomic H/C ratio in the microalga decreases with increasing torrefaction severity, whereas the atomic O/C ratio rises. The analysis suggests that the activation energy of isothermal torrefaction is 57.52×10(3)Jmol(-1), while it is between 40.14×10(3) and 88.41×10(3)Jmol(-1) for non-isothermal torrefaction. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Isolation and partial characterization of mutants with elevated lipid content in Chlorella sorokiniana and Scenedesmus obliquus.

    Science.gov (United States)

    Vigeolas, Hélène; Duby, Francéline; Kaymak, Esra; Niessen, Guillaume; Motte, Patrick; Franck, Fabrice; Remacle, Claire

    2012-11-30

    This paper describes the isolation and partial biomass characterization of high triacylglycerol (TAG) mutants of Chlorella sorokiniana and Scenedesmus obliquus, two algal species considered as potential source of biodiesel. Following UV mutagenesis, 2000 Chlorella and 2800 Scenedesmus colonies were screened with a method based on Nile Red fluorescence. Several mutants with high Nile Red fluorescence were selected by this high-throughput method in both species. Growth and biomass parameters of the strongest mutants were analyzed in detail. All of the four Chlorella mutants showed no significant changes in growth rate, cell weight, cell size, protein and chlorophyll contents on a per cell basis. Whereas all contained elevated total lipid and TAG content per unit of dry weight, two of them were also affected for starch metabolism, suggesting a change in biomass/storage carbohydrate composition. Two Scenedesmus mutants showed a 1.5 and 2-fold increased cell weight and larger cells compared to the wild type, which led to a general increase of biomass including total lipid and TAG content on a per cell basis. Such mutants could subsequently be used as commercial oleaginous algae and serve as an alternative to conventional petrol. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Effects of artificial sweeteners on metal bioconcentration and toxicity on a green algae Scenedesmus obliquus.

    Science.gov (United States)

    Hu, Hongwei; Deng, Yuanyuan; Fan, Yunfei; Zhang, Pengfei; Sun, Hongwen; Gan, Zhiwei; Zhu, Hongkai; Yao, Yiming

    2016-05-01

    The ecotoxicity of heavy metals depends much on their speciation, which is influenced by other co-existing substances having chelating capacity. In the present study, the toxic effects of Cd(2+) and Cu(2+) on a green algae Scenedesmus obliquus were examined in the presence of two artificial sweeteners (ASs), acesulfame (ACE) and sucralose (SUC) by comparing the cell specific growth rate μ and pulse-amplitude-modulated (PAM) parameters (maximal photosystem II photochemical efficiency Fv/Fm, actual photochemical efficiency Yield, and non-photochemical quenching NPQ) of the algae over a 96-h period. Simultaneously, the bioconcentration of the metals by the algal cells in the presence of the ASs was measured. The presence of ACE enhanced the growth of S. obliquus and promoted the bioconcentration of Cd(2+) in S. obliquus, while the impacts of SUC were not significant. Meanwhile, EC50 values of Cd(2+) on the growth of S. obliquus increased from 0.42 mg/L to 0.54 mg/L and 0.48 mg/L with the addition of 1.0 mg/L ACE and SUC, respectively. As for Cu(2+), EC50 values increased from 0.13 mg/L to 0.17 mg/L and 0.15 mg/L with the addition of 1.0 mg/L ACE and SUC, respectively. In summary, the two ASs reduced the toxicity of the metals on the algae, with ACE showing greater effect than SUC. Although not as sensitive as the cell specific growth rate, PAM parameters could disclose the mechanisms involved in metal toxicity at subcellular levels. This study provides the first evidence for the possible impact of ASs on the ecotoxicity of heavy metals. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Biodiesel quality and biochemical changes of microalgae Chlorella pyrenoidosa and Scenedesmus obliquus in response to nitrate levels.

    Science.gov (United States)

    Wu, Hongqin; Miao, Xiaoling

    2014-10-01

    Biodiesel quality associated with biochemical components of Chlorella pyrenoidosa and Scenedesmus obliquus under different nitrate levels were investigated. The highest lipid contents of 54.5% for C. pyrenoidosa and 47.7% for S. obliquus were obtained in nitrate absence. Carbohydrate peaked at 0.3gL(-1) with values of 40.7% for C. pyrenoidosa and 42.5% for S. obliquus. Protein content seemed species dependent, which decreased substantially to 11.2% in C. pyrenoidosa and 8.8% in S. obliquus under nitrate absence in present research. Better biodiesel quality (e.g. cetane number >58, iodine value microalgae grown in the presence of nitrogen may limit biodiesel quality. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Combined ecotoxicity of binary zinc oxide and copper oxide nanoparticles to Scenedesmus obliquus.

    Science.gov (United States)

    Ye, Nan; Wang, Zhuang; Fang, Hao; Wang, Se; Zhang, Fan

    2017-05-12

    A combined ecotoxicity study was carried out with nano-zinc oxide (nZnO) and nano-copper oxide (nCuO) to freshwater algae Scenedesmus obliquus. Concentration-response analysis indicated that the dissolved metal fraction was not the major source of individual and combined toxicity of the metal-oxide nanoparticles (MONPs). Moreover, the contribution of the nCuO (based on metallic mass) to the combined toxicity was greater than that of the nZnO. The observed combined toxicity can be predicted by the pharmacological concepts of concentration addition (CA) and independent action (IA). Combined toxicity prediction (in terms of median effect concentration) based on both concepts tends to overestimate the overall observed toxicity of the MONP mixtures. CA was more accurate for predicting the combined toxicity than IA. It may be concluded that CA gives a valid estimation of the overall ecotoxicity for mixtures comprising of similar acting MONPs.

  11. Change in Photosystem II Photochemistry During Algal Growth Phases of Chlorella vulgaris and Scenedesmus obliquus.

    Science.gov (United States)

    Oukarroum, Abdallah

    2016-06-01

    Sensitivity of photosynthetic processes towards environmental stress is used as a bioanalytical tool to evaluate the responses of aquatic plants to a changing environment. In this paper, change of biomass density, chlorophyll a fluorescence and photosynthetic parameters during growth phases of two microalgae Chlorella vulgaris and Scenedesmus obliquus were studied. The photosynthetic growth behaviour changed significantly with cell age and algae species. During the exponential phase of growth, the photosynthesis capacity reached its maximum and decreased in ageing algal culture during stationary phase. In conclusion, the chlorophyll a fluorescence OJIP method and the derived fluorescence parameters would be an accurate method for obtaining information on maximum photosynthetic capacities and monitoring algal cell growth. This will contribute to more understanding, for example, of toxic actions of pollutants in microalgae test.

  12. Accumulation of dieldrin in an alga (Scenedesmus obliquus), Daphnia magna, and the guppy (Poecilia reticulata)

    Science.gov (United States)

    Reinert, Robert E.

    1972-01-01

    Scenedesmus obliquus, Daphnia magna, and Poecilia reticulata accumulated dieldrin directly from water; average concentration factors (concentration in organism, dry weight, divided by concentration in water) were 1282 for the alga, 13,954 for D. magna, and 49,307 (estimated) for the guppy. The amount accumulated by each species at equilibrium (after about 1.5, 3-4, and 18 days, respectively) was directly proportional to the concentration of dieldrin in the water. Daphnia magna and guppies accumulated more dieldrin from water than from food that had been exposed to similar concentrations in water. When guppies were fed equal daily rations of D. magna containing different concentrations of insecticide, the amounts of dieldrin accumulated by the fish were directly proportional to the concentration in D. magna; when two lots of guppies were fed different quantities of D. magna (10 and 20 organisms per day) containing identical concentrations of dieldrin, however, the amounts accumulated did not differ substantially.

  13. Effect of nutrients on total lipid content and fatty acids profile of Scenedesmus obliquus

    Directory of Open Access Journals (Sweden)

    Behrouz Zarei Darki

    2017-05-01

    Full Text Available ABSTRACT The effect of nutrients on the total lipid content and fatty acid profile of Scenedesmus obliquus isolated from the south coast of the Caspian Sea was evaluated. The nutritional compositions of the media impacted the growth rate and biomass of S. obliquus that ranged from 0.175 day-1 to 0.209 day-1and 0.92 gr·l-1 to 1.79 gr·l-1, respectively. The alga grew better in the medium which was characterized by higher levels of sodium and trace elements such as Fe, Mn, Mo, and Co and poor in N and P as compared with the other media. The highest level of the total lipid (32% and the highest values of saturated fatty acids, in particular palmitic acid also were positively correlated with these nutrients. Peaks in polyunsaturated fatty acids (43.7 %, especially α-linolenic acid (28.4% were related to N and P, but its correlation with K and Mg was more evident. The most important factors correlated with high amount of monounsaturated fatty acids were also N and P, followed by K and Mg to a lesser extent. This study demonstrated that the same algal strain may be a source of different amount of fatty acids, depending on the composition of the culture medium.

  14. Enhancing lutein productivity of an indigenous microalga Scenedesmus obliquus FSP-3 using light-related strategies.

    Science.gov (United States)

    Ho, Shih-Hsin; Chan, Ming-Chang; Liu, Chen-Chun; Chen, Chun-Yen; Lee, Wen-Lung; Lee, Duu-Jong; Chang, Jo-Shu

    2014-01-01

    Lutein, one of the main photosynthetic pigments, is a promising natural product with both nutritional and pharmaceutical applications. In this study, light-related strategies were applied to enhance the cell growth and lutein production of a lutein-rich microalga Scenedesmus obliquus FSP-3. The results demonstrate that using white LED resulted in better lutein production efficiency when compared to the other three monochromatic LEDs (red, blue, and green). The lutein productivity of S. obliquus FSP-3 was further improved by adjusting the type of light source and light intensity. The optimal lutein productivity of 4.08 mg/L/d was obtained when using a TL5 fluorescent lamp at a light intensity of 300 μmol/m(2)/s, and this performance is better than that reported in most related studies. Moreover, the time-course profile of lutein accumulation in the microalga shows that the maximal lutein content and productivity were obtained at the onset of nitrogen depletion. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Bioethanol production from Scenedesmus obliquus sugars. The influence of photobioreactors and culture conditions on biomass production

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, J.R.; Passarinho, P.C.; Gouveia, L. [Laboratorio Nacional de Energia e Geologia (LNEG), Lisbon (Portugal). Unidade de Bioenergia

    2012-10-15

    A closed-loop vertical tubular photobioreactor (PBR), specially designed to operate under conditions of scarce flat land availability and irregular solar irradiance conditions, was used to study the potential of Scenedesmus obliquus biomass/sugar production. The results obtained were compared to those from an open-raceway pond and a closed-bubble column. The influence of the type of light source and the regime (natural vs artificial and continuous vs light/dark cycles) on the growth of the microalga and the extent of the sugar accumulation was studied in both PBRs. The best type of reactor studied was a closed-loop PBR illuminated with natural light/dark cycles. In all the cases, the relationship between the nitrate depletion and the sugar accumulation was observed. The microalga Scenedesmus was cultivated for 53 days in a raceway pond (4,500 L) and accumulated a maximum sugar content of 29 % g/g. It was pre-treated for carrying out ethanol fermentation assays, and the highest ethanol concentration obtained in the hydrolysate fermented by Kluyveromyces marxianus was 11.7 g/L. (orig.)

  16. Bioenergetic Strategy for the Biodegradation of p-Cresol by the Unicellular Green Alga Scenedesmus obliquus

    Science.gov (United States)

    Papazi, Aikaterini; Assimakopoulos, Konstantinos; Kotzabasis, Kiriakos

    2012-01-01

    Cultures from the unicellular green alga Scenedesmus obliquus biodegrade the toxic p-cresol (4-methylphenol) and use it as alternative carbon/energy source. The biodegradation procedure of p-cresol seems to be a two-step process. HPLC analyses indicate that the split of the methyl group (first step) that is possibly converted to methanol (increased methanol concentration in the growth medium), leading, according to our previous work, to changes in the molecular structure and function of the photosynthetic apparatus and therefore to microalgal biomass increase. The second step is the fission of the intermediately produced phenol. A higher p-cresol concentration results in a higher p-cresol biodegradation rate and a lower total p-cresol biodegradability. The first biodegradation step seems to be the most decisive for the effectiveness of the process, because methanol offers energy for the further biodegradation reactions. The absence of LHCII from the Scenedesmus mutant wt-lhc stopped the methanol effect and significantly reduced the p-cresol biodegradation (only 9%). The present contribution deals with an energy distribution between microalgal growth and p-cresol biodegradation, activated by p-cresol concentration. The simultaneous biomass increase with the detoxification of a toxic phenolic compound (p-cresol) could be a significant biotechnological aspect for further applications. PMID:23251641

  17. Grazer-induced defenses in Scenedesmus (Chlorococcales; Chlorophyceae): coenobium and spine formation

    NARCIS (Netherlands)

    Lürling, M.; Beekman, W.

    1999-01-01

    Three strains of the nonspiny Scenedesmus acutus Meyen, one strain of the nonspiny S. falcatus Chodat, and three strains of the spined Scenedesmus quadricauda (Turpin) Brebisson were cultured in standard medium and in medium containing filtered water from a culture of the grazer Daphnia. Nonspiny

  18. Photoacclimation of Scenedesmus protuberans (Chlorophyceae) to fluctuating irradiances simulating vertical mixing

    NARCIS (Netherlands)

    Flameling, I.A.; Kromkamp, J.C.

    1997-01-01

    Photoacclimation of Scenedesmus protuberans Fritsch to fluctuating irradiances, simulating vertical mixing, was studied in light-limited continuous cultures. The algae were exposed to a simple sinusoidal light regime simulating diurnal irradiance, and two fluctuating regimes in which light

  19. Enantioselective toxicities of chiral ionic liquids 1-alkyl-3-methyl imidazolium tartrate on Scenedesmus obliquus.

    Science.gov (United States)

    Liu, Huijun; Zhang, Xiaoqiang; Dong, Ying; Chen, Caidong; Zhu, Shimin; Ma, Xiangjuan

    2015-12-01

    Ionic liquids (ILs) are being used in various industries during the last few decades, while the good solubility and high stability of ILs may pose a potential threat to the aquatic environment. Effect of chiral ionic liquids (CILs) 1-alkyl-3-methyl imidazolium tartrate (RMIM T) on Scenedesmus obliquus (S.obliquus) was studied. The growth rate inhibition and cell membrane permeability increased with increasing RMIM T concentration and increasing alkyl chain lengths. The IC50 values of D-(-)-tartrate 1-hexyl-3-methyl imidazolium (D-(-)-HMIM T) were 28.30, 12.23,10.15 and 14.41 mg/L, respectively, at 24, 48, 72 and 96h. While that of L-(+)-tartrate 1-hexyl-3-methyl imidazolium (L-(+)-HMIM T) were 15.97, 7.91, 9.43 and 12.04 mg/L respectively. The concentration of chl a, chl b and chl (a+b) decreased with increasing RMIM T concentration. The chlorophyll fluorescence parameters (F0, Fv/Fm, Fv/F0, Y(II), ETR and NPQ) were affected by RMIM T, indicating that the RMIM T will damage the PSII, inhibit the transmission of excitation energy, decrease the efficiency of photosynthesis. The results showed that there were enantioselective toxicity of RMIM T to algae, and the toxicity of L-(+)-RMIM T was greater than that of D-(-)-RMIM T, but the enantioselective difference becomes smaller with increasing exposure time, and with the increasing carbon chain length of cation, indicating that cation properties may have a larger effect on toxicity than anion properties. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Expression of type 2 diacylglycerol acyltransferse gene DGTT1 from Chlamydomonas reinhardtii enhances lipid production in Scenedesmus obliquus.

    Science.gov (United States)

    Chen, Chun-Yen; Kao, Ai-Ling; Tsai, Zheng-Chia; Chow, Te-Jin; Chang, Hsin-Yueh; Zhao, Xin-Qing; Chen, Po-Ting; Su, Hsiang-Yen; Chang, Jo-Shu

    2016-03-01

    Microalgal strains of Scenedesmus obliquus have the great potential for the production of biofuels, CO2 fixation, and bioremediation. However, metabolic engineering of S. obliquus to improve their useful phenotypes are still not fully developed. In this study, S. obliquus strain CPC2 was genetically engineered to promote the autotrophic growth and lipid productivity. The overexpression plasmid containing the type 2 diacylglycerol acyltransferse (DGAT) gene DGTT1 from Chlamydomonas reinhardtii was constructed and transformed into S. obliquus CPC2, and the positive transformants were obtained. The expression of DGTT1 gene was confirmed by reverse transcription PCR analysis. Enhanced lipid content of the transformant S. obliquus CPC2-G1 by nearly two-fold was observed. The biomass concentration of the recombinant strains was also 29% higher than that of the wild-type strain. Furthermore, the recombinant strain CPC2-G1 was successfully grown in 40 L tubular type photobioreactor and open pond system in an outdoor environment. The lipid content, biomass concentration, and biomass productivity obtained from 40 L tubular PBR were 127.8% 20.0%, and 232.6% higher than those obtained from the wild-type strain. The major aim of this work is to develop a tool to genetically engineer an isolated S. obliquus strain for the desired purpose. This is the first report that genetic engineering of S. obliquus has been successful employed to improve both the microalgal cell growth and the lipid production. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Effects of imidazolium chloride ionic liquids and their toxicity to Scenedesmus obliquus.

    Science.gov (United States)

    Liu, Huijun; Zhang, Xiaoqiang; Chen, Caidong; Du, Shaoting; Dong, Ying

    2015-12-01

    The low volatility of ionic liquids effectively eliminates a major pathway for environmental release and contamination; however, the good solubility, low degree of environmental degradation and biodegradation of ILs may pose a potential threat to the aquatic environment. The growth inhibition of the green alga Scenedesmus obliquus by five 1-alkyl-3-methylimidazolium chloride ionic liquids (ILs) ([Cnmim]Cl, n=6, 8, 10, 12, 16) was investigated, and the effect on cellular membrane permeability and the ultrastructural morphology by ILs ([Cnmim]Cl, n=8, 12, 16) were studied. The results showed that the growth inhibition rate increased with increasing IL concentration and increasing alkyl chain lengths. The relative toxicity was determined to be [C6mim]Cl<[C8mim]Cl<[C10mim]Cl<[C12mim]Cl<[C16mim]Cl. The algae were most sensitive to imidazolium chloride ILs at 48 h according to the results from the growth inhibition rate and cellular membrane permeability tests. The ultrastructural morphology showed that the ILs had negative effects on the cellular morphology and structure of the algae. The cell wall of treated algae became wavy and separated from the cell membrane. Chloroplast grana lamellae became obscure and loose, osmiophilic material was deposited in the chloroplast, and mitochondria and their cristae swelled. Additionally, electron-dense deposits were observed in the vacuoles. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Effect of static magnetic field on the oxygen production of Scenedesmus obliquus cultivated in municipal wastewater.

    Science.gov (United States)

    Tu, Renjie; Jin, Wenbiao; Xi, Tingting; Yang, Qian; Han, Song-Fang; Abomohra, Abd El-Fatah

    2015-12-01

    Algal-bacterial symbiotic system, with biological synergism of physiological functions of both algae and bacteria, has been proposed for cultivation of microalgae in municipal wastewater for biomass production and wastewater treatment. The algal-bacterial symbiotic system can enhance dissolved oxygen production which enhances bacterial growth and catabolism of pollutants in wastewater. Therefore, the oxygen production efficiency of microalgae in algal-bacterial systems is considered as the key factor influencing the wastewater treatment efficiency. In the present study, we have proposed a novel approach which uses static magnetic field to enhance algal growth and oxygen production rate with low operational cost and non-toxic secondary pollution. The performance of oxygen production with the magnetic field was evaluated using Scenedesmus obliquus grown in municipal wastewater and was calculated based on the change in dissolved oxygen concentration. Results indicated that magnetic treatment stimulates both algal growth and oxygen production. Application of 1000 GS of magnetic field once at logarithmic growth phase for 0.5 h increased the chlorophyll-a content by 11.5% over the control after 6 days of growth. In addition, magnetization enhanced the oxygen production rate by 24.6% over the control. Results of the study confirmed that application of a proper magnetic field could reduce the energy consumption required for aeration during the degradation of organic matter in municipal wastewater in algal-bacterial symbiotic systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Reduced graphene oxide induces cytotoxicity and inhibits photosynthetic performance of the green alga Scenedesmus obliquus.

    Science.gov (United States)

    Du, Shaoting; Zhang, Peng; Zhang, Ranran; Lu, Qi; Liu, Lin; Bao, Xiaowei; Liu, Huijun

    2016-12-01

    Increased use of graphene materials might ultimately lead to their release into the environment. However, only a few studies have investigated the impact of graphene-based materials on green plants. In this study, the impact of reduced graphene oxide (RGO) on the microalgae Scenedesmus obliquus was evaluated to determine its phytotoxicity. Treatment with RGO suppressed the growth of the microalgae. The 72-h IC50 values of RGO evaluated using the logistic and Gompertz models were 148 and 151 mg L-1, respectively. RGO significantly inhibited Chl a and Chl a/b levels in the algal cells. Chlorophyll a fluorescence analysis showed that RGO significantly down-regulated photosystem II activity. The mechanism of how RGO inhibited algal growth and photosynthetic performance was determined by analyzing the alterations in ultrastructural morphology. RGO adhered to the algal cell surface as a semitranslucent coating. Cell wall damage and membrane integrity loss occurred in the treated cells. Moreover, nuclear chromatin clumping and starch grain number increase were noted. These changes might be attributed to the increase in malondialdehyde and reactive oxygen species levels, which might have exceeded the scavenging ability of antioxidant enzymes (including peroxidase and superoxide dismutase). RGO impaired the extra- and intra-cellular morphology and increased oxidative stress and thus inhibited algal growth and photosynthesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Utilization of seawater for cost-effective cultivation and harvesting of Scenedesmus obliquus.

    Science.gov (United States)

    Jung, Joo-Young; Lee, Hansol; Shin, Won-Sub; Sung, Min-Gyu; Kwon, Jong-Hee; Yang, Ji-Won

    2015-03-01

    Microalgae hold great promise as a source of biofuels and biochemicals. The main obstacles to their industrial application are the high cultivation and downstream costs related to media and harvesting. In the work, we explored the multiple potentials of seawater to address key issues relating to the cultivation of Scenedesmus obliquus. Seawater can sufficiently replace some of the key elements in BG11 medium such as MgSO4, CaCl2, and NaCO3, and its use can significantly reduce the quantity of water required for the preparation of culture media. Among our results, the total chlorophyll content in cells grown in modified BG11 using 10 % (v/v) seawater was increased 1.47-fold without sacrificing biomass or lipid production. More than 70 % of the total algal biomass was auto-flocculated within one hour when cells were grown in seawater-supplemented media, which compares very favorably with a yield of only 3 % from cells grown in BG11.

  5. Unraveling the molecular mechanism of photosynthetic toxicity of highly fluorescent silver nanoclusters to Scenedesmus obliquus.

    Science.gov (United States)

    Zhang, Li; Goswami, Nirmal; Xie, Jianping; Zhang, Bo; He, Yiliang

    2017-11-27

    While the discovery of numerous attractive properties of silver at the nanoscale has increased their demand in many sectors including medicine, optics, sensing, painting and cosmetics, it has also raised wide public concerns about their effect on living organisms in aquatic environment. Despite the continuous effort to understand the various aspects of the toxicity of silver nanomaterials, the molecular level understanding on their cytotoxicity mechanism to biological organisms has remained unclear. Herein, we demonstrated the underlying mechanism of the photosynthetic toxicity against green algae namely, Scenedesmus obliquus by using an emerging silver nanomaterial, called silver nanoclusters (defined as r-Ag NCs). By exploiting the unique fluorescence properties of r-Ag NCs along with various other analytical/biological tools, we proposed that the photosynthetic toxicity of r-Ag NCs was largely attributed to the "joint-toxicity" effect of particulate form of r-Ag NCs and its released Ag + , which resulted in the disruption of the electron transport chain of light reaction and affected the content of key enzymes (RuBP carboxylase/ oxygenase) of Calvin cycle of algae cells. We believe that the present study can also be applied to the assessment of the ecological risk derived from other metal nanoparticles.

  6. Oil extraction from Scenedesmus obliquus using a continuous microwave system--design, optimization, and quality characterization.

    Science.gov (United States)

    Balasubramanian, Sundar; Allen, James D; Kanitkar, Akanksha; Boldor, Dorin

    2011-02-01

    A 1.2 kW, 2450 MHz resonant continuous microwave processing system was designed and optimized for oil extraction from green algae (Scenedesmus obliquus). Algae-water suspension (1:1 w/w) was heated to 80 and 95°C, and subjected to extraction for up to 30 min. Maximum oil yield was achieved at 95°C and 30 min. The microwave system extracted 76-77% of total recoverable oil at 20-30 min and 95°C, compared to only 43-47% for water bath control. Extraction time and temperature had significant influence (p<0.0001) on extraction yield. Oil analysis indicated that microwaves extracted oil containing higher percentages of unsaturated and essential fatty acids (indicating higher quality). This study validates for the first time the efficiency of a continuous microwave system for extraction of lipids from algae. Higher oil yields, faster extraction rates and superior oil quality demonstrate this system's feasibility for oil extraction from a variety of feedstock. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. Removal of K+, Na+, Ca2+, and Mg2+ from saline-alkaline water using the microalga Scenedesmus obliquus

    Science.gov (United States)

    Yao, Zongli; Ying, Chengqi; Lu, Jianxue; Lai, Qifang; Zhou, Kai; Wang, Hui; Chen, Ling

    2013-11-01

    The capability of Scenedesmus obliquus to remove cations (K+, Na+, Ca2+, Mg2+) from saline-alkaline water was investigated at different salinities (0, 5, 10, 15, 20, 25) and carbonate alkalinities (0, 5, 10, 15, 20, 25, 30, 35 mmol/L). K+, Na+, Ca2+, and Mg2+ in saline-alkaline water were efficiently removed by S. obliquus. The maximum removal of the cations (29.37 mg for K+, 185.85 mg for Na+, 23.07 mg for Ca2+, 66.14 mg for Mg2+) occurred at salinity 25. The maximum removal of K+ (2.28 mg), Na+ (6.62 mg), Ca2+ (1.01 mg), and Mg2+ (0.62 mg) occurred at carbonate alkalinities of 25 mmol/L for K+, 35 mmol/L for Na+, 20 mmol/L for Ca2+, and 25 mmol/L for Mg2+, respectively. Under a salinity stress, the concentration of Na+ in S. obliquus increased significantly, while that of K+ decreased significantly. The concentrations of Ca2+ and Mg2+ decreased as well. The ratios of K+/Na+, Ca2+/Na+, and Mg2+/Na+ were significantly lower in all salinity treatments than those of the control. Under alkaline stress, the concentrations of Na+ and K+ in S. obliquus decreased significantly and the ratios of K+/Na+, Ca2+/Na+, and Mg2+/Na+ were significantly higher in all treatments than in the control. Moreover, the concentrations of Ca2+ and Mg2+ in S. obliquus at alkalinities of 5-10 mmol/L were significantly higher than those of the other treatments. The removal of Na+ by S. obliquus mainly occurs through biosorption, and Mg2+ and Ca2+ were removed through both biosorption and bioaccumulation.

  8. Effect of grazing-associated infochemicals on growth and morphological, development in Scenedesmus acutus (Chlorophyceae)

    NARCIS (Netherlands)

    Lürling, M.

    1998-01-01

    Populations of the phenotypically plastic alga Scenedesmus acutus Meyen were cultured in standard medium or in medium with filtered water from a Daphnia culture to examine the expression of ecomorphs in both water types. A rapid formation of four- and eight-celled coenobia was observed in the

  9. Investigations on the isoprenoid biosynthesis in the green alga Scenedesmus obliquus by using the {sup 13}C-labelling technique; Untersuchungen zur Biosynthese der Isoprenoide bei der Gruenalge Scenedesmus obliquus mittels {sup 13}C-Isotopenmarkierung

    Energy Technology Data Exchange (ETDEWEB)

    Schwender, J.

    1995-12-31

    The biosynthesis of several prenyllipids (isoprenoid lipids) of the green alga Scendesmus obliquus was investigated. The aim was to verify, whether the biosynthesis of isopentenyl diphosphate (IPP) in Scenedesmus proceeds according to the classical acetate mevalonate pathway or to an alternative pathway. An alternative pathway for IPP formation has recently been detected in some eubacteria by the group of Prof. M. Rohmer. Some inhibition tests were performed with mevinolin, a specific inhibitor of HMG-CoA reductase which yields mevalonic acid. Mevinolin should block the biosynthesis of such isoprenoids which are formed via the acetate mevalonate pathway. Scenedesmus was grown heterotrophically on {sup 13}C-labelled glucose or acetate. After isolation and purification of {sup 13}C-labelled phytol (side chains of chlorophylls), {beta}-carotene, lutein, plastoquinone-9 and three sterol compounds, the enrichment of {sup 13}C at different carbon-positions of the labelled compounds was determined. This was achieved by the {sup 13}C-NMR technique in cooperation with Miriam Seemann of the group of Prof. M. Rohmer in Mullhouse/France. (orig.) [Deutsch] Die Biosynthese verschiedener Isoprenoide und Prenyllipide der Gruenalge Scenedesmus obliquus wurde mittels eines Hemmtests und mittels spezifischen {sup 13}C-Markierungsexperimenten und NMR-Analysen untersucht. Es wurde in Sterilkulturen geprueft, ob der neue bakterielle Biosyntheseweg des Isopentenylpyrosphosphat (IPP), der nach Rohmer et al. bei einigen Eubakterien vorhanden ist und nicht ueber den klassischen Acetal-Mevalonat-Weg verlaeuft, bei Scenedesmus vorhanden ist. Zunaechst wurde mit Mevinolin, einem spezifischer Hemmstoff der HMG-CoA-Reduktase, versucht, das Wachstum oder die Isoprenoidbiosynthese einer autotroph wachsenden Scenedesmus-Kultur zu hemmen. Ausserdem wurden Medien entwickelt, mit denen Scenedesmus auf Glucose und auf Acetat heterotroph und ohne Hefeextrakt wachsen kann, um eine moeglichst effiziente

  10. Plutonium uptake by the green alga Scenedesmus obliquus (Turp) Kutz, as a function of isotope and oxidation state

    Energy Technology Data Exchange (ETDEWEB)

    Tkacik, M.F.

    1977-01-01

    This study was designed to determine the effect of plutonium chemical valence state on the availability of small concentrations of /sup 238/Pu and /sup 239/Pu to algae. The uptake experiments involved the green alga Scenedesmus obliquus, grown in batch cultures. Plutonium concentrations accumulated by this alga were linearly related to plutonium concentrations. There was no significant difference (rho = 0.05) in algal plutonium accumulations, on a mass basis, of either /sup 238/Pu or /sup 239/Pu in either Pu/sup +4/ or Pu/sup +6/ oxidation state at the concentrations studied.

  11. Kinetics of the oxyhydrogen reaction in the presence and absence of carbon dioxide in Scenedesmus obliquus

    Energy Technology Data Exchange (ETDEWEB)

    Erbes, D.L.; Gibbs, M.

    1981-01-01

    The oxyhydrogen reaction in the presence and absence of CO/sub 2/ was studied in H/sub 2/-adapted Scenedesmus obliquus by monitoring the initial rates of H/sub 2/, O/sub 2/, and /sup 14/CO/sub 2/ uptake and the effect of inhibitors on these rates with gas-sensing electrodes and isotopic techniques. In the presence of 0.02 atmosphere O/sub 2/, the pH/sub 2/ was varied from 0 to 1 atmosphere. Whereas the rate of O/sub 2/ uptake increased by only 30%, the rate of H/sub 2/ uptake increased severalfold over the range of pH/sub 2/ values. At 0.1 atmosphere H/sub 2/ and 0.02 atmosphere O/sub 2/, rates for H/sub 2/ and O/sub 2/ uptake were between 15 and 25 micromoles per milligram chlorophyll per hour. As the pH/sub 2/ was changed from 0 to 1 atmosphere, the quotient H/sub 2/:O/sub 2/ changed from 0 to roughly 2. This change may reflect the competition between H/sub 2/ and the endogenous respiratory electron donors. Respiration in the presence of glucose and acetate was also competitive with H/sub 2/ uptake. KCN inhibited equally respiration (O/sub 2/ uptake in the absence of H/sub 2/) and the oxyhydrogen reaction in the presence and absence of CO/sub 2/. The uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone accelerated the rate of respiration and the oxyhydrogen reaction to a similar extent. It was concluded that the oxyhydrogen reaction both in the presence and absence of CO/sub 2/ has properties in common with components of respiration and photosynthesis. Participation of these two processes in the oxyhydrogen reaction would require a closely linked shuttle between mitochondrion and chloroplast.

  12. Kinetics of the Oxyhydrogen Reaction in the Presence and Absence of Carbon Dioxide in Scenedesmus obliquus.

    Science.gov (United States)

    Erbes, D L; Gibbs, M

    1981-01-01

    The oxyhydrogen reaction in the presence and absence of CO(2) was studied in H(2)-adapted Scenedesmus obliquus by monitoring the initial rates of H(2), O(2), and (14)CO(2) uptake and the effect of inhibitors on these rates with gas-sensing electrodes and isotopic techniques. In the presence of 0.02 atmosphere O(2), the pH(2) was varied from 0 to 1 atmosphere. Whereas the rate of O(2) uptake increased by only 30%, the rate of H(2) uptake increased severalfold over the range of pH(2) values. At 0.1 atmosphere H(2) and 0.02 atmosphere O(2), rates for H(2) and O(2) uptake were between 15 and 25 micromoles per milligram chlorophyll per hour. As the pH(2) was changed from 0 to 1 atmosphere, the quotient H(2):O(2) changed from 0 to roughly 2. This change may reflect the competition between H(2) and the endogenous respiratory electron donors. Respiration in the presence of glucose and acetate was also competitive with H(2) uptake. KCN inhibited equally respiration (O(2) uptake in the absence of H(2)) and the oxyhydrogen reaction in the presence and absence of CO(2). The uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone accelerated the rate of respiration and the oxyhydrogen reaction to a similar extent. It was concluded that the oxyhydrogen reaction both in the presence and absence of CO(2) has properties in common with components of respiration and photosynthesis. Participation of these two processes in the oxyhydrogen reaction would require a closely linked shuttle between mitochondrion and chloroplast.

  13. The effect of discontinuous airlift mixing in outdoor flat panel photobioreactors on growth of Scenedesmus obliquus.

    Science.gov (United States)

    Leupold, Marco; Hindersin, Stefan; Kerner, Martin; Hanelt, Dieter

    2013-11-01

    Discontinuous airlift mixing was realized by injecting pressured air at time intervals with a frequency between 0.033 and 0.25 Hz (at 80 kPa; i.e., every 4-30 s; valve opening time 800 ms) into outdoor flat panel photobioreactors ([Formula: see text]). This caused a flow velocity between 2 and 20 cm s(-1) of the culture medium within the photobioreactor and the mixing time was between 38 and 103.5 s, requiring 0.175-1.340 L(gas volume) L(photobioreactor volume)(-1) min(-1) pressured air. In order to detect the effect on growth of Scenedesmus obliquus during outdoor experiments and to be able to compare obtained results, a batch run with an airlift frequency of 0.25 Hz was simultaneously used as control. Growth at different airlift frequencies was measured by the increase of cell dry weight (CDW) during 3-5 days and biomass yield on light energy was calculated. With increasing airlift frequencies, growth increased from 52 to 91 % compared to the control. When CDW was at around 1.0-1.5 g L(-1), airlift frequency had no effect on growth, indicating that mass transfer gradients of nutrients and gas were not the limiting factors of growth. Above 1.5 g CDW L(-1), growth increased with increasing airlift frequency and light limitation for a single cell occurred. This effect was observed during low and high irradiance and it is concluded that a higher mean flow causes a better light distribution, resulting in an enhanced growth. Biomass productivity and demand of pressured air are correlated logarithmically, which enables to save mixing energy during cultivation.

  14. The cell-wall glycoproteins of the green alga Scenedesmus obliquus. The predominant cell-wall polypeptide of Scenedesmus obliquus is related to the cell-wall glycoprotein gp3 of Chlamydomonas reinhardtii.

    Science.gov (United States)

    Voigt, Jürgen; Stolarczyk, Adam; Zych, Maria; Malec, Przemysław; Burczyk, Jan

    2014-02-01

    The green alga Scenedesmus obliquus contains a multilayered cell wall, ultrastructurally similar to that of Chlamydomonas reinhardtii, although its proportion of hydroxyproline is considerably lower. Therefore, we have investigated the polypeptide composition of the insoluble and the chaotrope-soluble wall fractions of S. obliquus. The polypeptide pattern of the chaotrope-soluble wall fraction was strongly modified by chemical deglycosylation with anhydrous hydrogen fluoride (HF) in pyridine indicating that most of these polypeptides are glycosylated. Polypeptide constituents of the chaotrope-soluble cell-wall fraction with apparent molecular masses of 240, 270, 265, and 135 kDa cross-reacted with a polyclonal antibody raised against the 100 kDa deglycosylation product of the C. reinhardtii cell-wall glycoprotein GP3B. Chemical deglycosylation of the chaotrope-soluble wall fraction resulted in a 135 kDa major polypeptide and a 106 kDa minor component reacting with the same antibody. This antibody recognized specific peptide epitopes of GP3B. When the insoluble wall fraction of S. obliquus was treated with anhydrous HF/pyridine, three polypeptides with apparent molecular masses of 144, 135, and 65 kDa were solubilized, which also occured in the deglycosylated chaotrope-soluble wall fraction. These findings indicate that theses glycoproteins are cross-linked to the insoluble wall fraction via HF-sensitive bonds. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  15. Effects of an anionic surfactant (FFD-6) on the energy and information flow between a primary producer (Scenedesmus obliquus) and a consumer (Daphnia magna)

    NARCIS (Netherlands)

    Lürling, M.; de Lange, H.J.; Peeters, E.T.H.M.

    2011-01-01

    The effects of a commercially available anionic surfactant solution (FFD-6) on growth and morphology of a common green alga (Scenedesmus obliquus) and on survival and clearance rates of the water flea Daphnia magna were studied. The surfactant-solution elicited a morphological response (formation of

  16. Importance of nutrient competition and allelopathic effects in suppression of the green alga Scenedesmus obliquus by the macrophytes Chara, Elodea and Myriophyllum

    NARCIS (Netherlands)

    Lürling, M.; Van Geest, G.J.; Scheffer, M.

    2006-01-01

    Possible allelopathic effects of substances released from the macrophytes Chara globularis, Elodea canadensis, Myriophyllum spicatum on the common green alga Scenedesmus obliquus were tested in the laboratory with plastic plants and untreated medium as controls. A two-phase approach was used in

  17. High Yields of Hydrogen Production Induced by Meta-Substituted Dichlorophenols Biodegradation from the Green Alga Scenedesmus obliquus

    Science.gov (United States)

    Papazi, Aikaterini; Andronis, Efthimios; Ioannidis, Nikolaos E.; Chaniotakis, Nikolaos; Kotzabasis, Kiriakos

    2012-01-01

    Hydrogen is a highly promising energy source with important social and economic implications. The ability of green algae to produce photosynthetic hydrogen under anaerobic conditions has been known for years. However, until today the yield of production has been very low, limiting an industrial scale use. In the present paper, 73 years after the first report on H2-production from green algae, we present a combinational biological system where the biodegradation procedure of one meta-substituted dichlorophenol (m-dcp) is the key element for maintaining continuous and high rate H2-production (>100 times higher than previously reported) in chloroplasts and mitochondria of the green alga Scenedesmus obliquus. In particular, we report that reduced m-dcps (biodegradation intermediates) mimic endogenous electron and proton carriers in chloroplasts and mitochondria, inhibit Photosystem II (PSII) activity (and therefore O2 production) and enhance Photosystem I (PSI) and hydrogenase activity. In addition, we show that there are some indications for hydrogen production from sources other than chloroplasts in Scenedesmus obliquus. The regulation of these multistage and highly evolved redox pathways leads to high yields of hydrogen production and paves the way for an efficient application to industrial scale use, utilizing simple energy sources and one meta-substituted dichlorophenol as regulating elements. PMID:23145057

  18. Biodegradation of carbamazepine using freshwater microalgae Chlamydomonas mexicana and Scenedesmus obliquus and the determination of its metabolic fate.

    Science.gov (United States)

    Xiong, Jiu-Qiang; Kurade, Mayur B; Abou-Shanab, Reda A I; Ji, Min-Kyu; Choi, Jaeyoung; Kim, Jong Oh; Jeon, Byong-Hun

    2016-04-01

    This study evaluated the toxicity and cellular stresses of carbamazepine (CBZ) on Chlamydomonas mexicana and Scenedesmus obliquus, and its biodegradation by both microalgal species. The growth of both microalgal species decreased with increase of CBZ concentration. The growth of S. obliquus was significantly inhibited (97%) at 200 mg CBZ L(-1), as compared to the control after 10days; whereas, C. mexicana showed 30% inhibition at the same experimental conditions. Biochemical characteristics including total chlorophyll, carotenoid contents and enzyme activities (SOD and CAT) for both species were affected by CBZ at relatively high concentration. C. mexicana and S. obliquus could achieve a maximum of 35% and 28% biodegradation of CBZ, respectively. Two metabolites (10,11-dihydro-10,11-expoxycarbamazepine and n-hydroxy-CBZ) were identified by UPLC-MS, as a result of CBZ biodegradation by C. mexicana. This study demonstrated that C. mexicana was more tolerant to CBZ and could be used for treatment of CBZ contaminated wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Growth and lipid accumulation characteristics of Scenedesmus obliquus in semi-continuous cultivation outdoors for biodiesel feedstock production.

    Science.gov (United States)

    Feng, Pingzhong; Yang, Kang; Xu, Zhongbin; Wang, Zhongming; Fan, Lu; Qin, Lei; Zhu, Shunni; Shang, Changhua; Chai, Peng; Yuan, Zhenhong; Hu, Lei

    2014-12-01

    In an effort to identify suitable microalgal species for biodiesel production, seven species were isolated from various habitats and their growth characteristics were compared. The results demonstrated that a green alga Scenedesmus obliquus could grow more rapidly and synthesize more lipids than other six microalgal strains. S. obliquus grew well both indoors and outdoors, and reached higher μmax indoors than that outdoors. However, the cells achieved higher dry weight (4.36 g L(-1)), lipid content (49.6%) and productivity (183 mg L(-1) day(-1)) outdoors than in indoor cultures. During the 61 days semi-continuous cultivation outdoors, high biomass productivities (450-550 mg L(-1) day(-1)) and μmax (1.05-1.44 day(-1)) were obtained. The cells could also achieve high lipid productivities (151-193 mg L(-1) day(-1)). These results indicated that S. obliquus was promising for lipids production in semi-continuous cultivation outdoors. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Effect of Nano-Al₂O₃ on the Toxicity and Oxidative Stress of Copper towards Scenedesmus obliquus.

    Science.gov (United States)

    Li, Xiaomin; Zhou, Suyang; Fan, Wenhong

    2016-06-09

    Nano-Al₂O₃ has been widely used in various industries; unfortunately, it can be released into the aquatic environment. Although nano-Al₂O₃ is believed to be of low toxicity, it can interact with other pollutants in water, such as heavy metals. However, the interactions between nano-Al₂O₃ and heavy metals as well as the effect of nano-Al₂O₃ on the toxicity of the metals have been rarely investigated. The current study investigated copper toxicity in the presence of nano-Al₂O₃ towards Scenedesmus obliquus. Superoxide dismutase activity and concentration of glutathione and malondialdehyde in cells were determined in order to quantify oxidative stress in this study. Results showed that the presence of nano-Al₂O₃ reduced the toxicity of Cu towards S. obliquus. The existence of nano-Al₂O₃ decreased the growth inhibition of S. obliquus. The accumulation of copper and the level of oxidative stress in algae were reduced in the presence of nano-Al₂O₃. Furthermore, lower copper accumulation was the main factor that mitigated copper toxicity with the addition of nano-Al₂O₃. The decreased copper uptake could be attributed to the adsorption of copper onto nanoparticles and the subsequent decrease of available copper in water.

  1. Metagenome changes in the mesophilic biogas-producing community during fermentation of the green alga Scenedesmus obliquus.

    Science.gov (United States)

    Wirth, Roland; Lakatos, Gergely; Böjti, Tamás; Maróti, Gergely; Bagi, Zoltán; Kis, Mihály; Kovács, Attila; Ács, Norbert; Rákhely, Gábor; Kovács, Kornél L

    2015-12-10

    A microalgal biomass offers a potential alternative to the maize silage commonly used in biogas technology. In this study, photoautotrophically grown Scenedesmus obliquus was used as biogas substrate. This microalga has a low C/N ratio of 8.5 relative to the optimum 20-30. A significant increase in the ammonium ion content was not observed. The methane content of the biogas generated from Sc. obliquus proved to be higher than that from maize silage, but the specific biogas yield was lower. Semi-continuous steady biogas production lasted for 2 months. Because of the thick cell wall of Sc. obliquus, the biomass-degrading microorganisms require additional time to digest its biomass. The methane concentration in the biogas was also high, in co-digestion (i.e., 52-56%) as in alga-fed anaerobic digestion (i.e., 55-62%). These results may be related to the relative predominance of the order Clostridiales in co-digestion and to the more balanced C/N ratio of the mixed algal-maize biomass. Predominance of the order Methanosarcinales was observed in the domain Archaea, which supported the diversity of metabolic pathways in the process. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  2. Enantioselective oxidative stress and oxidative damage caused by Rac- and S-metolachlor to Scenedesmus obliquus.

    Science.gov (United States)

    Liu, Huijun; Xia, YiLu; Cai, Weidan; Zhang, Yina; Zhang, Xiaoqiang; Du, Shaoting

    2017-04-01

    The rational use and environmental security of chiral pesticides has gained the interest of many researchers. The enantioselective effects of Rac- and S-metolachlor on oxidative stress in Scenedesmus obliquus were determined in this study. Stronger green fluorescence was observed in response to S-metolachlor treatment than to Rac-metolachlor treatment, suggesting that more reactive oxygen species (ROS) were stimulated by S-metolachlor. ROS levels following S-metolachlor treatment were 1.92-, 8.31-, and 1.08-times higher than those observed following Rac-metolachlor treatment at 0.1, 0.2, and 0.3 mg/L, respectively. Superoxide dismutase (SOD) and catalase (CAT) were stimulated with increasing herbicide concentrations, with S-metolachlor exhibiting a greater effect. Oxidative damage in terms of chlorophyll (Chl) content, cellular membrane permeability, and cellular ultrastructures of S. obliquus were investigated. Chla and Chlb contents in algae treated with Rac-metolachlor were 2-6-fold higher than those in algae treated with S-metolachlor at 0.1, 0.2, and 0.3 mg/L. The cellular membrane permeability of algae exposed to 0.3 mg/L Rac- and S-metolachlor was 6.19- and 42.5-times that of the control. Correlation analysis implied that ROS are the major factor responsible for the oxidative damage caused by Rac- and S-metolachlor. Damage to the chloroplasts and cell membrane of S. obliquus, low production of starch granules, and an increased number of vacuoles were observed upon ultrastructural morphology analysis by transmission electron microscope. These results indicate that S-metolachlor has a greater effect on S. obliquus than Rac-metolachlor. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. “Rational” Management of Dichlorophenols Biodegradation by the Microalga Scenedesmus obliquus

    Science.gov (United States)

    Papazi, Aikaterini; Kotzabasis, Kiriakos

    2013-01-01

    The microalga Scenedesmus obliquus exhibited the ability to biodegrade dichlorophenols (dcps) under specific autotrophic and mixotrophic conditions. According to their biodegradability, the dichlorophenols used can be separated into three distinct groups. Group I (2,4-dcp and 2,6 dcp – no meta-substitution) consisted of quite easily degraded dichlorophenols, since both chloride substituents are in less energetically demanding positions. Group II (2,3-dcp, 2,5-dcp and 3,4-dcp – one meta-chloride) was less susceptible to biodegradation, since one of the two substituents, the meta one, required higher energy for C-Cl-bond cleavage. Group III (3,5-dcp – two meta-chlorides) could not be biodegraded, since both chlorides possessed the most energy demanding positions. In general, when the dcp-toxicity exceeded a certain threshold, the microalga increased the energy offered for biodegradation and decreased the energy invested for biomass production. As a result, the biodegradation per cell volume of group II (higher toxicity) was higher, than group I (lower toxicity) and the biodegradation of dichlorophenols (higher toxicity) was higher than the corresponding monochlorophenols (lower toxicity). The participation of the photosynthetic apparatus and the respiratory mechanism of microalga to biodegrade the group I and the group II, highlighted different bioenergetic strategies for optimal management of the balance between dcp-toxicity, dcp-biodegradability and culture growth. Additionally, we took into consideration the possibility that the intermediates of each dcp-biodegradation pathway could influence differently the whole biodegradation procedures. For this reason, we tested all possible combinations of phenolic intermediates to check cometabolic interactions. The present contribution bring out the possibility of microalgae to operate as “smart” bioenergetic “machines”, that have the ability to continuously “calculate” the energy reserves and

  4. Effects of nitrogen source availability and bioreactor operating strategies on lutein production with Scenedesmus obliquus FSP-3.

    Science.gov (United States)

    Ho, Shih-Hsin; Xie, Youping; Chan, Ming-Chang; Liu, Chen-Chun; Chen, Chun-Yen; Lee, Duu-Jong; Huang, Chieh-Chen; Chang, Jo-Shu

    2015-05-01

    In this study, the effects of the type and concentration of nitrogen sources on the cell growth and lutein content of an isolated microalga Scenedesmus obliquus FSP-3 were investigated. With batch culture, the highest lutein content (4.61 mg/g) and lutein productivity (4.35 mg/L/day) were obtained when using 8.0 mM calcium nitrate as the nitrogen source. With this best nitrogen source condition, the microalgae cultivation was performed using two bioreactor strategies (namely, semi-continuous and two-stage operations) to further enhance the lutein content and productivity. Using semi-continuous operation with a 10% medium replacement ratio could obtain the highest biomass productivity (1304.8 mg/L/day) and lutein productivity (6.01 mg/L/day). This performance is better than most related studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Photosynthesis of Scenedesmus obliquus in outdoor open thin-layer cascade system in high and low CO2 in Belgium.

    Science.gov (United States)

    de Marchin, Thomas; Erpicum, Michel; Franck, Fabrice

    2015-12-10

    Two outdoor open thin-layer cascade systems operated as batch cultures with the alga Scenedesmus obliquus were used to compare the productivity and photosynthetic acclimations in control and CO2 supplemented cultures in relation with the outdoor light irradiance. We found that the culture productivity was limited by CO2 availability. In the CO2 supplemented culture, we obtained a productivity of up to 24gdwm(-2)day(-1) and found a photosynthetic efficiency (value based on the PAR solar radiation energy) of up to 5%. In the CO2 limited culture, we obtained a productivity of up to 10gdwm(-2)day(-1) while the photosynthetic efficiency was up to 3.3% and decreased to 2.1% when the integrated daily PAR increased. Fluorescence and oxygen evolution measurements showed that ETR and oxygen evolution light saturation curves, as well as light-dependent O2 uptake were similar in algal samples from both cultures when the CO2 limitation was removed. In contrast, we found that CO2 limitation conducted to a decreased PSII photochemical efficiency and an increased light-induced heat-dissipation in the control culture compared to the CO2 supplemented culture. These features are in line with a lower light use efficiency and may therefore contribute to the lower productivity observed in absence of CO2 supplementation in outdoor mass cultures of S. obliquus. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. A MULTISTAGE GRADUAL NITROGENREDUCTION STRATEGY FOR INCREASED LIPID PRODUCTIVITY AND NITROGEN REMOVAL IN WASTEWATER USING Chlorella vulgaris AND Scenedesmus obliquus

    Directory of Open Access Journals (Sweden)

    J. C. Robles-Heredia

    2015-06-01

    Full Text Available AbstractChlorella vulgaris and Scenedesmus obliquuswere grown in artificial-wastewater using a new nitrogen-limitation strategy aimed at increasing lipid productivity. This strategy consisted in a multi-stage process with sequential reduction of N-NH4 concentration (from 90 to 60, 40, and 20 mg.L-1 to promote a balance between cell growth and lipid accumulation. Lipid productivity was compared against a reference process consisting of nitrogen reduction in two stages, where the nitrogen concentration was suddenly reduced from 90 mg.L-1 to three different concentrations (10, 20, and 30 mg.L-1. In the multi-stage mode, only C. vulgaris exhibited a net lipid-productivity increase. Lipid content of S. obliquus did not present a significant increase, thus decreasing lipid productivity. The highest lipid productivities were observed in the two-stage mode for both S. obliquus and C. vulgaris (194.9 and 133.5 mg.L-1.d-1, respectively, and these values are among the highest reported in the literature to date.

  7. Effect of flue gas CO2 on the growth, carbohydrate and fatty acid composition of a green microalga Scenedesmus obliquus for biofuel production.

    Science.gov (United States)

    Ji, Min-Kyu; Yun, Hyun-Shik; Hwang, Jae-Hoon; Salama, El-Sayed; Jeon, Byong-Hun; Choi, Jaeyoung

    2017-08-01

    Effect of various flue gas CO2 concentrations (5%, 10% and 14.1%) on growth rate and biochemical properties of a green microalga Scenedesmus obliquus was investigated. S. obliquus showed the highest biomass production and growth rate (0.36 g L(-1) and μmax = 1.00 day(-1)), total inorganic carbon removal (35.8 mg L(-1)), lipid productivity (9.9 mg L(-1) day) and carbohydrate productivity (10.3 mg L(-1) day) with 14.1% CO2 after 8 days of cultivation. Fatty acid methyl ester analysis revealed that the palmitic and oleic acid contents were increased up to 5% and 7% with 14.1% CO2, respectively. Application of flue gas CO2 enhanced the growth along with lipid and carbohydrate productivity of S. obliquus, which can be exploited for reducing the CO2 concentration.

  8. Effect of subcellular distribution on nC₆₀ uptake and transfer efficiency from Scenedesmus obliquus to Daphnia magna.

    Science.gov (United States)

    Chen, Qiqing; Hu, Xialin; Yin, Daqiang; Wang, Rui

    2016-06-01

    The potential uptake and trophic transfer ability of nanoparticles (NPs) in aquatic organisms have not been well understood yet. There has been an increasing awareness of the subcellular fate of NPs in organisms, but how the subcellular distribution of NPs subsequently affects the trophic transfer to predator remains to be answered. In the present study, the food chain from Scenedesmus obliquus to Daphnia magna was established to simulate the trophic transfer of fullerene aqueous suspension (nC60). The nC60 contaminated algae were separated into three fractions: cell wall (CW), cell organelle (CO), and cell membrane (CM) fractions, and we investigated the nC60 uptake amounts and trophic transfer efficiency to the predator through dietary exposure to algae or algal subcellular fractions. The nC60 distribution in CW fraction of S. obliquus was the highest, following by CO and CM fractions. nC60 uptake amounts in D. magna were found to be mainly relative to the NPs' distribution in CW fraction and daphnia uptake ability from CW fraction, whereas the nC60 trophic transfer efficiency (TE) were mainly in accordance with the transfer ability of NPs from the CO fraction. CW fed group possessed the highest uptake amount, followed by CO and CM fed groups, but the presence of humic acid (HA) significantly decreased the nC60 uptake from CW fed group. The CO fed groups acquired high TE values for nC60, while CM fed groups had low TE values. Moreover, even though CW fed group had a high TE value; it decreased significantly with the presence of HA. This study contributes to the understanding of fullerene NPs' dietary exposure to aquatic organisms, suggesting that NPs in different food forms are not necessarily equally trophically available to the predator. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. RISING WATER TEMPERATURES ALTER LIPID DYNAMICS AND REDUCE N-3 ESSENTIAL FATTY ACID CONCENTRATIONS IN SCENEDESMUS OBLIQUUS (CHLOROPHYTA)(1).

    Science.gov (United States)

    Fuschino, Jenny R; Guschina, Irina A; Dobson, Gary; Yan, Norman D; Harwood, John L; Arts, Michael T

    2011-08-01

    The biosynthesis of nutritionally important polyunsaturated fatty acids (PUFAs) in phytoplankton is influenced by environmental temperature. We investigated the potential of climate warming to alter lipid dynamics of Scenedesmus obliquus (Turpin) Kütz. by comparing lipid and fatty acid (FA) profiles as well as FA metabolism (using [1-(14) C] acetate) at 20°C and 28°C. We documented an overall decline (53%-37%) in the proportion of n-3 PUFA (in particular, of α-linolenic acid [ALA; 18:3n-3]), and a concomitant increase in saturated fatty acids (SAFAs) in total lipids (TLs) at 28°C, consistent with enhanced incorporation of radioactivity from [1-(14) C] acetate into total 16:0, 18:1, and decreased incorporation into 18:2 and 18:3 FA (from 36% to 22% of the total) at 28°C. Glycerophospholipids were also affected by warming; ALA and stearidonic acids (SDAs; 18:4n-3) both decreased (by 13% and 15%, respectively) in phosphatidylcholine (PC) and (by 24% and 20%, respectively) in phosphatidylethanolamine (PE). The characteristic FA in phosphatidylglycerol (PG; 16:1n-13t) increased (by 22%) at 28°C. The activities of desaturases, which add double bonds to FA moieties, comprised the major suite of reactions affected by the temperature increase in TL and polar lipid (PL) classes. Climate modelers predict an increase in the number of extreme heat days in summer at temperate latitudes, with parallel projected increases in water temperatures of shallow water bodies. Our results suggest that the overall decrease in the essential n-3 FA ALA in S. obliquus at higher water temperatures may lower food quality for higher tropic levels, adding another climate-warming stress. Her Majesty the Queen in Right of Canada [2011].

  10. Metribuzin impairs the unicell-colony transformation in the green alga Scenedesmus obliquus

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.

    2011-01-01

    Active growth is a prerequisite for the formation of grazing-protective, mostly eight-celled colonies by the ubiquitous green alga Scenedesmus in response to chemical cues from zooplankton. Colonies can also be evoked by chemically quite similar manmade anionic surfactants, such as FFD-6. In this

  11. Cultivation of Scenedesmus obliquus in liquid hydrolysate from flash hydrolysis for nutrient recycling.

    Science.gov (United States)

    Barbera, Elena; Sforza, Eleonora; Kumar, Sandeep; Morosinotto, Tomas; Bertucco, Alberto

    2016-05-01

    The production of biofuels from microalgae is associated with high demands of nutrients (nitrogen and phosphorus) required for growth. Recycling nutrients from the residual biomass is essential to obtain a sustainable production. In this work, the aqueous phase obtained from flash hydrolysis of Scenedesmus sp. was used as cultivation medium for a microalga of the same genus, to assess the feasibility of this technique for nutrient recycling purposes. Batch and continuous cultivations were carried out, to determine growth performances in this substrate compared to standard media, and verify if a stable biomass production could be obtained. In continuous experiments, the effect of hydrolysate inlet concentration and of residence time were assessed to optimize nutrient supply in relation to productivity. Results obtained show that nutrient recycling is feasible by treating biomass with flash hydrolysis, and Scenedesmus is capable of recycling large amounts of recovered nutrients. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Influence of carbon dioxide, temperature, medium kind and light intensity on the growth of algae Chlamydomonas reinhardtii and Scenedesmus obliquus

    Directory of Open Access Journals (Sweden)

    Olejnik Przemysław Piotr

    2016-01-01

    Full Text Available Microalgae attracts the attention of scientists because of the possibility of using in the energy industry as one of the substrates for the production of renewable energy. So far, the greatest emphasis was put on attempts to obtain strains, and technologies of their culturing, in order to efficiently acquire fat from cells and its further conversion to biodiesel using transesterification reaction. Increasingly, algae are considered also as an efficient biomass producer, which can be used as a substrate for methane production in biogas plants. In this study the influence of different physical and chemical conditions, on the growth of two algae species: Chlamydomonasreinhardtii and Scenedesmus obliquus was investigated. Based on the literature and the data obtained for the algae growth on the standard medium and the digestate remaining after fermentation, one may suggest further investigations on the use of other liquid waste from agriculture and industry for algae breeding, including chemical. analysis and supplementation of these mediums so as to provide the best conditions for their growth.

  13. Fixed-bed biosorption of cadmium using immobilized Scenedesmus obliquus CNW-N cells on loofa (Luffa cylindrica) sponge.

    Science.gov (United States)

    Chen, Bor-Yann; Chen, Chun-Yen; Guo, Wan-Qian; Chang, Hao-Wei; Chen, Wen-Ming; Lee, Duu-Jong; Huang, Chieh-Chen; Ren, Nan-Qi; Chang, Jo-Shu

    2014-05-01

    A continuous fixed-bed biosorption process was established for cadmium (Cd) removal by Scenedesmus obliquus CNW-N (isolated from southern Taiwan) cells immobilized onto loofa sponge. This immobilized-cell biosorption process allows better recovery and reusability of the microalgal biomass. The growth of microalgae on the matrix support with appropriate nutrient supplementation could enhance the overall metal removal activity. Major operating parameters (e.g., feeding flow rate, cycle number of medium replacement, and particle diameter of the sponge) were studied for treatability evaluation. The most promising cell growth on the sponge support was obtained at a flow rate of 0.284 bed volume (BV)/min, sponge particle diameter of 1 cm, and with one cycle of medium replacement. The performance of fixed-bed biosorption (adsorption capacity of 38.4 mg, breakthrough time at 15.5 h) was achieved at a flow rate of 5 ml/min with an influent concentration of 7.5 mg Cd/l. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Effects of an anionic surfactant (FFD-6) on the energy and information flow between a primary producer (Scenedesmus obliquus) and a consumer (Daphnia magna).

    Science.gov (United States)

    Lürling, M; de Lange, H J; Peeters, E T H M

    2011-11-01

    The effects of a commercially available anionic surfactant solution (FFD-6) on growth and morphology of a common green alga (Scenedesmus obliquus) and on survival and clearance rates of the water flea Daphnia magna were studied. The surfactant-solution elicited a morphological response (formation of colonies) in Scenedesmus at concentrations of 10-100 μl l(-1) that were far below the No Observed Effect Concentration (NOEC) value of 1,000 μl l(-1) for growth inhibition. The NOEC-value of FFD-6 for colony-induction was 3 μl l(-1). Daphnia survival was strongly affected by FFD-6, yielding LC(50-24h) and LC(50-48 h) of 148 and 26 μl l(-1), respectively. In addition, clearance rates of Daphnia feeding on unicellular Scenedesmus were inhibited by FFD-6, yielding a 50% inhibition (EC(50-1.5h)) at 5.2 μl l(-1) with a NOEC of 0.5 μl l(-1). When Daphnia were offered FFD-6-induced food in which eight-celled colonies (43 × 29 μm) were most abundant, clearance rates (~0.14 ml ind.(-1) h(-1)) were only 25% the rates of animals that were offered non-induced unicellular (15 × 5 μm) Scenedesmus (~0.56 ml ind.(-1) h(-1)). As FFD-6 concentrations in the treated food used in the experiments were far below the NOEC for clearance rate inhibition, it is concluded that the feeding rate depression was caused by the altered morphology of the Scenedesmus moving them out of the feeding window of the daphnids. The surfactant evoked a response in Scenedesmus that is similar to the natural chemically induced defensive reaction against grazers and could disrupt the natural information conveyance between these plankton organisms.

  15. Kinetics of the Oxyhydrogen Reaction in the Presence and Absence of Carbon Dioxide in Scenedesmus obliquus1

    Science.gov (United States)

    Erbes, David L.; Gibbs, Martin

    1981-01-01

    The oxyhydrogen reaction in the presence and absence of CO2 was studied in H2-adapted Scenedesmus obliquus by monitoring the initial rates of H2, O2, and 14CO2 uptake and the effect of inhibitors on these rates with gas-sensing electrodes and isotopic techniques. In the presence of 0.02 atmosphere O2, the pH2 was varied from 0 to 1 atmosphere. Whereas the rate of O2 uptake increased by only 30%, the rate of H2 uptake increased severalfold over the range of pH2 values. At 0.1 atmosphere H2 and 0.02 atmosphere O2, rates for H2 and O2 uptake were between 15 and 25 micromoles per milligram chlorophyll per hour. As the pH2 was changed from 0 to 1 atmosphere, the quotient H2:O2 changed from 0 to roughly 2. This change may reflect the competition between H2 and the endogenous respiratory electron donors. Respiration in the presence of glucose and acetate was also competitive with H2 uptake. KCN inhibited equally respiration (O2 uptake in the absence of H2) and the oxyhydrogen reaction in the presence and absence of CO2. The uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone accelerated the rate of respiration and the oxyhydrogen reaction to a similar extent. It was concluded that the oxyhydrogen reaction both in the presence and absence of CO2 has properties in common with components of respiration and photosynthesis. Participation of these two processes in the oxyhydrogen reaction would require a closely linked shuttle between mitochondrion and chloroplast. PMID:16661612

  16. Mixotrophic cultivation of a microalga Scenedesmus obliquus in municipal wastewater supplemented with food wastewater and flue gas CO2 for biomass production.

    Science.gov (United States)

    Ji, Min-Kyu; Yun, Hyun-Shik; Park, Young-Tae; Kabra, Akhil N; Oh, In-Hwan; Choi, Jaeyoung

    2015-08-15

    The biomass and lipid/carbohydrate production by a green microalga Scenedesmus obliquus under mixotrophic condition using food wastewater and flue gas CO2 with municipal wastewater was investigated. Different dilution ratios (0.5-2%) of municipal wastewater with food wastewater were evaluated in the presence of 5, 10 and 14.1% CO2. The food wastewater (0.5-1%) with 10-14.1% CO2 supported the highest growth (0.42-0.44 g L(-1)), nutrient removal (21-22 mg TN L(-1)), lipid productivity (10-11 mg L(-1)day(-1)) and carbohydrate productivity (13-16 mg L(-1)day(-1)) by S. obliquus after 6 days of cultivation. Food wastewater increased the palmitic and oleic acid contents up to 8 and 6%, respectively. Thus, application of food wastewater and flue gas CO2 can be employed for enhancement of growth, lipid/carbohydrate productivity and wastewater treatment efficiency of S. obliquus under mixotrophic condition, which can lead to development of a cost effective strategy for microalgal biomass production. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. How DNA barcoding can be more effective in microalgae identification: a case of cryptic diversity revelation in Scenedesmus (Chlorophyceae)

    Science.gov (United States)

    Zou, Shanmei; Fei, Cong; Wang, Chun; Gao, Zhan; Bao, Yachao; He, Meilin; Wang, Changhai

    2016-01-01

    Microalgae identification is extremely difficult. The efficiency of DNA barcoding in microalgae identification involves ideal gene markers and approaches employed, which however, is still under the way. Although Scenedesmus has obtained much research in producing lipids its identification is difficult. Here we present a comprehensive coalescent, distance and character-based DNA barcoding for 118 Scenedesmus strains based on rbcL, tufA, ITS and 16S. The four genes, and their combined data rbcL + tufA + ITS + 16S, rbcL + tufA and ITS + 16S were analyzed by all of GMYC, P ID, PTP, ABGD, and character-based barcoding respectively. It was apparent that the three combined gene data showed a higher proportion of resolution success than the single gene. In comparison, the GMYC and PTP analysis produced more taxonomic lineages. The ABGD generated various resolution in discrimination among the single and combined data. The character-based barcoding was proved to be the most effective approach for species discrimination in both single and combined data which produced consistent species identification. All the integrated results recovered 11 species, five out of which were revealed as potential cryptic species. We suggest that the character-based DNA barcoding together with other approaches based on multiple genes and their combined data could be more effective in microalgae diversity revelation. PMID:27827440

  18. Cadmium tolerance, cysteine and thiol peptide levels in wild type and chromium-tolerant strains of Scenedesmus acutus (Chlorophyceae)

    Energy Technology Data Exchange (ETDEWEB)

    Torricelli, Elena; Gorbi, Gessica; Pawlik-Skowronska, Barbara; Di Toppi, Luigi Sanita; Corradi, Maria Grazia

    2004-07-14

    Two strains of the unicellular green alga Scenedesmus acutus with different sensitivity to hexavalent chromium were compared for their tolerance of cadmium, by means of growth and recovery tests, and determination of cysteine, reduced glutathione and phytochelatin content, after short-term exposure to various cadmium concentrations (from 1.125 to 27 {mu}M). Growth experiments showed that, after 7-day treatments with cadmium, the chromium-tolerant strain reached a significantly higher cell density and, after 24-h exposure to Cd, was able to resume growth significantly better than the wild type. Constitutive level of cysteine was higher in the chromium-tolerant strain, while glutathione levels were similar in the two strains. The higher content of cysteine and the maintenance of both reduced glutathione and phytochelatin high levels in the presence of cadmium, support the higher cadmium co-tolerance of the chromium-tolerant strain in comparison with the wild type one.

  19. High pH-induced flocculation-sedimentation and effect of supernatant reuse on growth rate and lipid productivity of Scenedesmus obliquus and Chlorella vulgaris.

    Science.gov (United States)

    Castrillo, M; Lucas-Salas, L M; Rodríguez-Gil, C; Martínez, D

    2013-01-01

    High pH-induced flocculation-sedimentation of Scenedesmus obliquus and Chlorella vulgaris was studied with the objective of improving the efficiency of microalgae harvesting, since it is one of the most expensive steps of production of microalgae. Desired pH values were achieved by addition of NaOH and Ca(OH)(2). Growth rate and lipid productivity in fresh media prepared with tap water and with analytical-grade water, and in reused media prepared with culture centrifuged supernatant and the supernatant from high pH-induced flocculation-sedimentation were compared. Since the growth rates for reused media were about 1.7 times higher than in fresh media, and the lipid productivities were about 25 and 26 mg L(-1) d(-1) in flocculated and centrifuged reused media respectively, medium reuse is a suitable method of saving water and nutrients. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Impacts of dissolved organic matter on aqueous behavior of nano/micron-titanium nitride and their induced enzymatic/non-enzymatic antioxidant activities in Scenedesmus obliquus.

    Science.gov (United States)

    Zhang, Xin; Wang, Zhuang; Wang, Se; Fang, Hao; Zhang, Fan; Wang, De-Gao

    2017-01-02

    Freshwater dispersion stability and ecotoxicological effects of titanium nitride (TiN) with particle size of 20 nm, 50 nm, and 2-10 μm in the presence of dissolved organic matter (DOM) at various concentrations were studied. The TiN particles that had a more negative zeta potential and smaller hydrodynamic size showed more stable dispersion in an aqueous medium when DOM was present than when DOM was absent. Biochemical assays indicated that relative to the control, the TiN particles in the presence of DOM alleviated to some extent the antioxidative stress enzyme activity in Scenedesmus obliquus. In addition, it was found that the TiN with a primary size of 50 nm at a high concentration presented a significant impact on non-enzymatic antioxidant defense in algal cells.

  1. Effect of Solvent System on Extractability of Lipidic Components of Scenedesmus obliquus (M2-1) and Gloeothece sp. on Antioxidant Scavenging Capacity Thereof

    Science.gov (United States)

    Amaro, Helena M.; Fernandes, Fátima; Valentão, Patrícia; Andrade, Paula B.; Sousa-Pinto, I.; Malcata, F. Xavier; Guedes, A. Catarina

    2015-01-01

    Microalgae are well known for their biotechnological potential, namely with regard to bioactive lipidic components—especially carotenoids and polyunsaturated fatty acids (PUFA), well-known for therapeutic applications based on their antioxidant capacity. The aim of this work was to evaluate the influence of four distinct food-grade solvents upon extractability of specific lipidic components, and on the antioxidant capacity exhibited against both synthetic (2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS+•)) and biological reactive species (O2•− and •NO−). A eukaryotic microalga (Scenedesmus obliquus (M2-1)) and a prokaryotic one (Gloeothece sp.) were used as case studies. Concerning total antioxidant capacity, the hexane:isopropanol (3:2) and acetone extracts of Sc. obliquus (M2-1) were the most effective against DPPH• and ABTS+•, respectively. Gloeothece sp. ethanol extracts were the most interesting scavengers of O2•−, probably due the high content of linolenic acid. On the other hand, acetone and hexane:isopropanol (3:2) extracts were the most interesting ones in •NO− assay. Acetone extract exhibited the best results for the ABTS assay, likely associated to its content of carotenoids, in both microalgae. Otherwise, ethanol stood out in PUFA extraction. Therefore, profiles of lipidic components extracted are critical for evaluating the antioxidant performance—which appears to hinge, in particular, on the balance between carotenoids and PUFAs. PMID:26492257

  2. Effect of Solvent System on Extractability of Lipidic Components of Scenedesmus obliquus (M2-1 and Gloeothece sp. on Antioxidant Scavenging Capacity Thereof

    Directory of Open Access Journals (Sweden)

    Helena M. Amaro

    2015-10-01

    Full Text Available Microalgae are well known for their biotechnological potential, namely with regard to bioactive lipidic components—especially carotenoids and polyunsaturated fatty acids (PUFA, well-known for therapeutic applications based on their antioxidant capacity. The aim of this work was to evaluate the influence of four distinct food-grade solvents upon extractability of specific lipidic components, and on the antioxidant capacity exhibited against both synthetic (2,2-diphenyl-1-picrylhydrazyl (DPPH• and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS+• and biological reactive species (O2•- and •NO-. A eukaryotic microalga (Scenedesmus obliquus (M2-1 and a prokaryotic one (Gloeothece sp. were used as case studies. Concerning total antioxidant capacity, the hexane:isopropanol (3:2 and acetone extracts of Sc. obliquus (M2-1 were the most effective against DPPH• and ABTS+•, respectively. Gloeothece sp. ethanol extracts were the most interesting scavengers of O2•-, probably due the high content of linolenic acid. On the other hand, acetone and hexane:isopropanol (3:2 extracts were the most interesting ones in •NO- assay. Acetone extract exhibited the best results for the ABTS assay, likely associated to its content of carotenoids, in both microalgae. Otherwise, ethanol stood out in PUFA extraction. Therefore, profiles of lipidic components extracted are critical for evaluating the antioxidant performance—which appears to hinge, in particular, on the balance between carotenoids and PUFAs.

  3. The toxicity of ionic liquid 1-decylpyridinium bromide to the algae Scenedesmus obliquus: Growth inhibition, phototoxicity, and oxidative stress.

    Science.gov (United States)

    Liu, Dingdong; Liu, Huijun; Wang, Shengtao; Chen, Jiazheng; Xia, Yilu

    2017-10-18

    Although ionic liquids (ILs) are unlikely to act as air contaminants, their high solubility and slow degradation make them a potential threat to the aquatic environment. The IL 1-decylpyridinium bromide ([DPy]Br) is a common type of pyridine IL, which has varied applications such as in extraction, separation, and catalytic synthesis. Herein, the toxicity of [DPy]Br to S. obliquus is determined. Growth was inhibited by high-concentration [DPy]Br, whereas it had a hormetic effect at low concentrations. The IC50-96h was approximately 0.06mg/L. The cell membrane permeability of S. obliquus increased with [DPy]Br concentration, indicating that [DPy]Br can cause damage to the algae cell structure. Chlorophyll content decreased at high [DPy]Br concentration; chlorophyll fluorescence parameters, such as the maximum effective quantum yield of PSII (Fv/Fm), potential activity of PSII (Fv/F0), yield of the photochemical quantum [Y(II)], and the non-photochemical quenching coefficient (NPQ) were affected, suggesting that [DPy]Br can damage PSII. The ROS fluorescent images revealed that the morphology of cells changed gradually from fusiform to round. High ROS levels were observed with high concentrations of [DPy]Br, indicating that [DPy]Br induced oxidative stress on S. obliquus. The SOD and CAT activities increased when the concentration was lower than IC50, whereas they decreased when the concentration was higher than IC50. The relative ROS content was significantly correlated with growth inhibition rate, cell membrane permeability, chlorophyll content, and SOD and CAT activities. The increase of ROS content in algal cells is an important toxicological mechanism of [DPy]Br to S. obliquus. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. The synergistic effects for the co-cultivation of oleaginous yeast-Rhodotorula glutinis and microalgae-Scenedesmus obliquus on the biomass and total lipids accumulation.

    Science.gov (United States)

    Yen, Hong-Wei; Chen, Pin-Wen; Chen, Li-Juan

    2015-05-01

    In this co-culture of oleaginous yeast-Rhodotorula glutinis and microalgae-Scenedesmus obliquus, microalgae potentially acts as an oxygen generator for the growth of aerobic yeast while the yeast mutually provides CO2 to the microalgae as both carry out the production of lipids. To explore the synergistic effects of co-cultivation on the cells growth and total lipids accumulation, several co-culture process parameters including the carbon source concentration, temperature and dissolved oxygen level would be firstly investigated in the flask trials. The results of co-culture in a 5L photobioreactor revealed that about 40-50% of biomass increased and 60-70% of total lipid increased was observed as compared to the single culture batches. Besides the synergistic effects of gas utilization, the providing of trace elements to each other after the natural cells lysis was believed to be another benefit to the growth of the overall co-culture system. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Enhanced CO2 sequestration by a novel microalga: Scenedesmus obliquus SA1 isolated from bio-diversity hotspot region of Assam, India.

    Science.gov (United States)

    Basu, Samarpita; Roy, Abhijit Sarma; Mohanty, Kaustubha; Ghoshal, Aloke K

    2013-09-01

    The present study aimed to isolate a high CO2 and temperature tolerant microalga capable of sequestering CO2 from flue gas. Microalga strain SA1 was isolated from a freshwater body of Assam and identified as Scenedesmus obliquus (KC733762). At 13.8±1.5% CO2 and 25 °C, maximum biomass (4.975±0.003 g L(-1)) and maximum CO2 fixation rate (252.883±0.361 mg L(-1) d(-1)) were obtained which were higher than most of the relevant studies. At elevated temperature (40 °C) and 13.8±1.5% CO2 maximum biomass (0.883±0.001 g L(-1)) was obtained. The carbohydrate, protein, lipid, and chlorophyll content of the CO2 treated SA1 were 30.87±0.64%, 9.48±1.65%, 33.04±0.46% and 6.03±0.19% respectively, which were higher than previous reports. Thus, SA1 could prove to be a potential candidate for CO2 sequestration from flue gas as well as for the production of value added substances. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Growth modeling of the green microalga Scenedesmus obliquus in a hybrid photobioreactor as a practical tool to understand both physical and biochemical phenomena in play during algae cultivation.

    Science.gov (United States)

    Tramontin, Deise P; Gressler, Pablo D; Rörig, Leonardo R; Derner, Roberto B; Pereira-Filho, Jurandir; Radetski, Claudemir M; Quadri, Marintho B

    2017-12-02

    In recent years, numerous studies have justified the use of microalgae as a sustainable alternative for the generation of different types of fuels, food supplementation, and cosmetics, as well as bioremediation processes. To improve the cost/benefit ratio of microalgae mass production, many culture systems have been built and upgraded. Mathematical modeling the growth of different species in different systems has become an efficient and practical tool to understand both physical and biochemical phenomena in play during algae cultivation. In addition, growth modeling can guide design changes that lead to process optimization. In the present work, growth of the green microalga Scenedesmus obliquus was modeled in a hybrid photobioreactor that combines the characteristics of tubular photobioreactors (TPB) with thin-layer cascades (TLC). The system showed productivity greater than 8.0 g m-2 day-1 (dry mass) for CO2 -fed cultures, and the model proved to be an accurate representation of experimental data with R2 greater than 0.7 for all cases under variable conditions of temperature and irradiance to determine subsystem efficiency. Growth modeling also allowed growth prediction relative to the operating conditions of TLC, making it useful for estimating the system given other irradiance and temperature conditions, as well as other microalgae species. © 2017 Wiley Periodicals, Inc.

  7. Temperature-dependent sensitivity of growth and photosynthesis of Scenedesmus obliquus, Navicula pelliculosa and two strains of Microcystis aeruginosa to the herbicide atrazine.

    Science.gov (United States)

    Chalifour, Annie; Juneau, Philippe

    2011-05-01

    The temperature-dependent sensitivities of two algal species and two strains of cyanobacteria to the photosynthesis-inhibiting herbicide atrazine were evaluated in order to understand how the interaction between acclimation temperature and herbicide will affect growth and photosynthesis of aquatic microorganisms. The green alga Scenedesmus obliquus, the diatom Navicula pelliculosa and a toxic and non-toxic strain of Microcystis aeruginosa were acclimated to three different temperatures (10, 15 and 25°C) and exposed to five concentrations of the herbicide atrazine (0-0.15μM) for 72h. Growth, photosynthetic yields, energy fluxes within photosystem II and pigment content were then measured as potential responses to each treatment. With the exception of N. pelliculosa, the toxicity of atrazine was higher when microorganisms were acclimated to lower temperatures. N. pelliculosa was not only the most tolerant to atrazine, but also had a similar sensitivity to this herbicide at every temperature. The observed differences in growth sensitivity to atrazine at low temperature are associated with the ability of algae and cyanobacteria to cope with high excitation pressure, by increasing its protective carotenoid content and non-photochemical energy dissipation. Our results demonstrate that future guidelines for the protection of aquatic life should consider water temperature as an important factor influencing the toxicity of atrazine to aquatic microorganisms. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  8. The effect of light color on the nucleocytoplasmic and chloroplast cycle of the green chlorococcal alga Scenedesmus obliquus

    Czech Academy of Sciences Publication Activity Database

    Cepák, Vladislav; Přibyl, Pavel; Vítová, Milada

    2006-01-01

    Roč. 51, č. 4 (2006), s. 342-348 ISSN 0015-5632 R&D Projects: GA ČR(CZ) GA204/03/1113; GA MŠk(CZ) 1M0571 Institutional research plan: CEZ:AV0Z60050516; CEZ:AV0Z50200510 Keywords : color lights * cell cycle * Scenedesmus Subject RIV: EF - Botanics Impact factor: 0.963, year: 2006

  9. Modulatory effects of Zn2+ ions on the toxicity of citrate- and PVP-capped gold nanoparticles towards freshwater algae, Scenedesmus obliquus.

    Science.gov (United States)

    Iswarya, V; Johnson, J B; Parashar, Abhinav; Pulimi, Mrudula; Chandrasekaran, N; Mukherjee, Amitava

    2017-02-01

    Gold nanoparticles (GNPs) are widely used for medical purposes, both in diagnostics as well as drug delivery, and hence are prone to release and distribution in the environment. Thus, we have explored the effects of GNPs with two distinct surface capping (citrate and PVP), and three different sizes (16, 27, and 37 nm) at 0.01-, 0.1-, and 1-mg L-1 concentrations on a predominant freshwater alga Scenedesmus obliquus in the sterile freshwater matrix. We have also investigated how an abundant metal ion from freshwater, i.e., Zn2+ ions may modulate the effects of the selected GNPs (40 nm, citrate, and PVP capped). Preliminary toxicity results revealed that gold nanoparticles were highly toxic in comparison to zinc ions alone. A significant modulation in the toxicity of Zn ions was not noticed in the presence of GNPs. In contrast, zinc ions minimized the toxicity produced by GNPs (both CIT-37 and PVP-37), despite its individual toxicity. Approximately, about 42, 33, and 25% toxicity reduction was noted at 0.05-, 0.5-, and 5-mg L-1 Zn ions, respectively, for CIT-37 GNPs, while 31% (0.05 mg L-1), 24% (0.5 mg L-1), and 9% (5 mg L-1) of toxicity reduction were noted for PVP-37 GNPs. Maximum toxicity reduction was seen at 0.05 mg L-1 of Zn ions. Abbott modeling substantiated antagonistic effects offered by Zn2+ ions on GNPs. Stability and sedimentation data revealed that the addition of zinc ions gradually induced the aggregation of NPs and in turn significantly reduced the toxicity of GNPs. Thus, the naturally existing ions like Zn2+ have an ability to modulate the toxicity of GNPs in a real-world environment scenario.

  10. Feasibility of CO2 mitigation and carbohydrate production by microalga Scenedesmus obliquus CNW-N used for bioethanol fermentation under outdoor conditions: effects of seasonal changes.

    Science.gov (United States)

    Ho, Shih-Hsin; Chen, Yi-Di; Chang, Ching-Yu; Lai, Yen-Ying; Chen, Chun-Yen; Kondo, Akihiko; Ren, Nan-Qi; Chang, Jo-Shu

    2017-01-01

    Although outdoor cultivation systems have been widely used for mass production of microalgae at a relatively low cost, there are still limited efforts on outdoor cultivation of carbohydrate-rich microalgae that were further used as feedstock for fermentative bioethanol production. In particular, the effects of seasonal changes on cell growth, CO2 fixation, and carbohydrate production of the microalgae have not been well investigated. This work demonstrates the feasibility of using outdoor tubular photobioreactors (PBR) for whole-year-round cultivation of a carbohydrate-rich microalga Scenedesmus obliquus CNW-N in southern Taiwan. Time-course profile of the carbohydrate content under nitrogen-deficient conditions was monitored to assess the seasonal changes. The optimal CO2 fixation rate and carbohydrate productivity were 430.2 mg L(-1) d(-1)and 111.8 mg L(-1)d(-1), respectively, which were obtained during the summer time. Under nitrogen starvation, the microalgal biomass can accumulate nearly 45-50% of carbohydrates, mainly composed of glucose that accounted for 70-80% of the total carbohydrates in the microalgal cells. This glucose-rich microalgal biomass is apparently a very suitable carbon source for bioethanol fermentation. This work shows the feasibility of combining CO2 fixation and bioethanol production using microalgae grown in outdoor photobioreactors as feedstock. The understanding of the seasonal changes in the carbohydrate productivity makes this approach more practically viable. The novel strategy proposed in this study could be a promising alternative to the existing technology dealing with CO2 mitigation and biofuels production.

  11. Impact of tetracycline on the toxic effects of titanium dioxide (TiO2) nanoparticles towards the freshwater algal species, Scenedesmus obliquus.

    Science.gov (United States)

    Iswarya, V; Sharma, Vineet; Chandrasekaran, N; Mukherjee, Amitava

    2017-12-01

    Titanium dioxide nanoparticles (TiO2 NPs) are the most risk assessed nanoparticles in the aquatic environment due to their increased usage in the various sectors from electronics to consumer products. The natural aquatic system also comprises of numerous toxicants like antibiotics, whose impact on the toxicity of nanoparticles are less assessed. Hence, it is essential to determine the effect of other toxicants on the TiO2 NP toxicity. In the current study, the impact of antibiotic (tetracycline, TC) on the toxic effect of TiO2 NPs was studied on a freshwater alga, Scenedesmus obliquus. The median effective concentrations (EC50) of TiO2 NPs and TC were noted to be 136.88±2.30μM and 0.63±0.02μM, respectively. Based on the EC50 obtained, three different concentrations of TC, such as 0.34, 0.68, and 1.36μM have been selected to evaluate their effect on the toxicity of 18.75, 37.5, and 75μM of TiO2 NPs. Existence of TC provoked the growth inhibition of TiO2 NPs at their lower concentrations. In contrast, a reduction in the growth inhibition was noted as the concentrations of TC and TiO2 NPs were increased. Abbott modeling confirmed the additive and antagonistic effects noted. The stability profile of TiO2 NPs elucidated the aggregation of NPs with an increase in time. Even though a similar trend has been followed for TiO2 NPs+TC, a significant difference in the aggregation has not been observed in most cases when compared with TiO2 NPs alone. The presence of TC lowered the Ti uptake by the algal cells, which portrayed the dominance of TC in the toxic effect of TiO2 NPs to be either additive or antagonistic. The SEM images of the algal cells upon exposure to TiO2 NPs, TC, and their mixture elucidated the aggregation of algal cells, cellular deformations like compromised cell membrane, and vacuole formation, etc. In addition, the release of algal exudates was also noticed as a protective layer over the cells to counteract the stress. EPS secretion in response to Ti

  12. Cytotoxicity of ZnO NPs towards fresh water algae Scenedesmus obliquus at low exposure concentrations in UV-C, visible and dark conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bhuvaneshwari, M.; Iswarya, V. [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India); Archanaa, S. [Department of Biotechnology, IIT Madras (India); Madhu, G.M. [Department of Chemical Engineering, M.S. Ramaiah Institute of Technology, Bangalore (India); Kumar, G.K. Suraish [Department of Biotechnology, IIT Madras (India); Nagarajan, R. [Department of Chemical Engineering, IIT Madras (India); Chandrasekaran, N. [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India); Mukherjee, Amitava, E-mail: amit.mookerjea@gmail.com [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India)

    2015-05-15

    Highlights: • The cytotoxicity of ZnO NPs with two hydrodynamic sizes towards freshwater algae. • Size dependent toxicity under UV-C, dark and visible light conditions. • Cytotoxicity principally due to ZnO NPs not the released Zn{sup 2+} ions. • The internalization of ZnO NPs leads to membrane damage and ROS production. - Abstract: Continuous increase in the usage of ZnO nanoparticles in commercial products has exacerbated the risk of release of these particles into the aquatic environment with possible harmful effects on the biota. In the current study, cytotoxic effects of two types of ZnO nanoparticles, having different initial effective diameters in filtered and sterilized lake water medium [487.5 ± 2.55 nm for ZnO-1 NPs and 616.2 ± 38.5 nm for ZnO-2 NPs] were evaluated towards a dominant freshwater algal isolate Scenedesmus obliquus in UV-C, visible and dark conditions at three exposure concentrations: 0.25, 0.5 and 1 mg/L. The toxic effects were found to be strongly dependent on the initial hydrodynamic particle size in the medium, the exposure concentrations and the irradiation conditions. The loss in viability, LDH release and ROS generation were significantly enhanced in the case of the smaller sized ZnO-1 NPs than in the case of ZnO-2 NPs under comparable test conditions. The toxicity of both types of ZnO NPs was considerably elevated under UV-C irradiation in comparison to that in dark and visible light conditions, the effects being more enhanced in case of ZnO-1 NPs. The size dependent dissolution of the ZnO NPs in the test medium and possible toxicity due to the released Zn{sup 2+} ions was also noted. The surface adsorption of the nanoparticles was substantiated by scanning electron microscopy. The internalization/uptake of the NPs by the algal cells was confirmed by fluorescence microscopy, transmission electron microscopy, and elemental analyses.

  13. Genealogy in Microspora (Chlorophyceae)

    NARCIS (Netherlands)

    Jong, de Y.S.D.M.; Lokhorst, G.M.; Kruijer, J.D.

    2000-01-01

    The genealogical relationships in the green algal genus Microspora (Chlorophyceae) are determined by phylogenetic analysis based on 15 ecological, morphological and reproductive characters. It is found that the traditional defining characters like cell shape and distinctness of the H-shaped pieces

  14. Genealogy in Microspora (Chlorophyceae)

    OpenAIRE

    de Jong,; Lokhorst, G.M.; Kruijer, J.D.

    2000-01-01

    The genealogical relationships in the green algal genus Microspora (Chlorophyceae) are determined by phylogenetic analysis based on 15 ecological, morphological and reproductive characters. It is found that the traditional defining characters like cell shape and distinctness of the H-shaped pieces (composing the cell wall) play a major role in rooting of the cladograms and that species – forming a prominent rope-like growth habit in rapid streams – are closely related. It is suggested that th...

  15. Changes in food quality of the green alga Scenedesmus induced by Daphnia infochemicals: biochemical composition and morphology

    NARCIS (Netherlands)

    Lürling, M.; De Lange, H.J.; Van Donk, E.

    1997-01-01

    1. The effects of Daphnia infochemicals on the morphology and biochemical composition of Scenedesmus were studied and subsequently their influence on Daphnia life history. Three species of Scenedesmus (S. acutus, S. obliquus and S. subspicatus) were tested for Daphnia-induced colony formation. Life

  16. Waste Utilization and Biodiesel Production by the Green Microalga Scenedesmus obliquus▿

    Science.gov (United States)

    Mandal, Shovon; Mallick, Nirupama

    2011-01-01

    Scenedesmus obliquus was cultivated in three types of waste discharges to couple waste treatment with biodiesel production. The lipid pool accumulation was boosted to 1.0 g liter−1 against 0.1 g liter−1 for the control. The waste-grown S. obliquus showed an increase in the content of the saturated fatty acid pool, which is desirable for good-quality biodiesel. PMID:21057012

  17. The dynamics of oil accumulation in Scenedesmus obliquus

    NARCIS (Netherlands)

    Breuer, G.

    2015-01-01

    .Abstract long Global demands for food and biofuels increase rapidly, together with an increase of concerns for depleting fossil resources and climate change. New sustainable sources of vegetable oil, from now on referred to as triacylglycerol (TAG), are therefore highly desired.

  18. Effects of food type on the life history of Daphnia clones from lakes differing in trophic state. I. Daphnia galeata feeding on Scenedesmus and Oscillatoria

    NARCIS (Netherlands)

    Repka, S.

    1997-01-01

    1. Effects of the green alga Scenedesmus obliquus and the filamentous cyanobacterium Oscillatoria limnetica as food sources on the growth and reproduction of nine Daphnia galeata clones were studied. A high concentration of these two algae species was fed to Daphnia clones collected from four lakes

  19. On the way to cyanobacterial blooms: impact of the herbicide metribuzin on the competition between a green alga (Scenedesmus) and a cyanobacterium (Microcystis)

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.; Roessink, I.

    2006-01-01

    The hypothesis that exposure to a common and widely applied photosynthesis-inhibiting herbicide, metribuzin, would alter the outcome of the competitive battle between susceptible green algae (Scenedesmus obliquus) and tolerant cyanobacteria (Microcystis aeruginosa) was tested. In a long-term (17d)

  20. Costs and trade-offs of grazer-induced defenses in Scenedesmus under deficient resource

    Science.gov (United States)

    Zhu, Xuexia; Wang, Jun; Chen, Qinwen; Chen, Ge; Huang, Yuan; Yang, Zhou

    2016-03-01

    The green alga Scenedesmus obliquus can form inducible defensive morphs under grazing threat. Costs and trade-offs of inducible defense are expected to accompany the benefits of defensive morphs, but are hard to detect under nutrient-sufficient experimental conditions. To test the existence of costs associated with inducible defense, we cultured S. obliquus along resource availability gradients in the presence or absence of infochemical cues from Daphnia, and measured the strength of defensive colony formation and fitness characters. Under the lowest phosphorous concentration, the expression of inducible defensive colony resulted in decreased growth rate, which provides direct evidence for physiological costs. Along the gradient reduction of phosphorous concentration or light intensity, inducible defense in S. obliquus showed a decreasing trend. However, the photosynthetic efficiency of S. obliquus was barely affected by its defense responses, suggesting that the negative correlations between resource availability and colony formation of this alga may be due to resource-based trade-offs in the allocation of limited resources. Thus, our results indicated that expression of inducible defense of S. obliquus was impaired under insufficient phosphorus or light. Furthermore, under severe phosphate deficiency, obvious physiological costs of inducible defense could be detected even though defensive colony formation also decreased significantly.

  1. Harvesting of freshwater microalgae biomass by Scenedesmus sp. as bioflocculant

    Science.gov (United States)

    Rinanti, A.; Purwadi, R.

    2018-01-01

    This study is particularly expected to provide information on the diversity of microalgae as the flocculant agent that gives the highest biomass yield. Bioflocculation was done by using one of the flocculating microalgae i.e. Scenedesmus obliquus to concentrate on non-flocculating microalgae Chlorella vulgaris. The freshwater microalgae S. obliquus tested it ability to harvest other non-flocculating microalgae, increased sedimentation rate in the flocculation process and increased biomass yield. The flocculation of biomass microalgae with chemical flocculant as comparison was done by adding alum (K2SO4·Al2 (SO4)3·24H2O). The addition of alum (K2SO4·Al2 (SO4)3·24H2O) as flocculant at pH 11 and S. obliquus sp. as bioflocculant caused significant alteration of nutrition of microalgae. Overall, the essential content produced by flocculation method with addition of alum or with bioflocculation (%, mg/100 mg dry weight) are lipid 31,64; 38,69, protein 30,79; 38.50%, and chlorophyll 0.6253; 0.8420). Harvesting with bioflocculation methods conducted at the end of the cultivation period increase the amount of biomass significantly and can accelerate the settling time of biomass. Harvesting microalgae cells by bioflocculation method becomes an economically competitive harvesting method compared to alum as a chemical flocculant because of the cheaper cost of flocculant, not toxic so it does not require further water treatment after harvesting due to the use of alum as chemical flocculants.

  2. Effects of linear alkylbenzene sulfonate (LAS) on the interspecific competition between Microcystis and Scenedesmus.

    Science.gov (United States)

    Zhu, Wei; Chen, Huaimin; Guo, Lili; Li, Ming

    2016-08-01

    The widespread use of detergents increases the concentration of surfactant in lakes and reservoirs. High surfactant loads produces toxicity to algae; however, the influence of the increasing surfactant on the competition between algae is not clear. In this paper, different amounts of linear alkylbenzene sulfonate (LAS) were added to test the effects of LAS on the competition between Microcystis aeruginosa and Scenedesmus obliquus under eutrophic condition. In single culture, the growth of S. obliquus was promoted under lower LAS concentrations (1 and 20 mg L(-1)), but cell density of S. obliquus reduced when treated with higher LAS concentration (100 mg L(-1)). The growth of M. aeruginosa was inhibited markedly with 20 and 100 mg L(-1) LAS. Compared with single culture, the result was opposite in co-cultures and the cell density of S. obliquus increased significantly when treated with LAS of 1, 20, and 100 mg L(-1). The specific growth rates of S. obliquus and M. aeruginosa in both cultures were 0.4-0.5 day(-1) and 0.6-0.7 day(-1), respectively, except that the specific growth rate of M. aeruginosa in both cultures treated with 100 mg L(-1) LAS was about 0.2 day(-1). M. aeruginosa dominated over S. obliquus in the co-culture without LAS, while the competition was completely opposite with the addition of 20 mg L(-1) LAS. The growth of S. obliquus treated with 20 mg L(-1) LAS was not affected significantly in single culture but was promoted by 75 % in co-culture. Moreover, the growth of S. obliquus in co-culture treated with 100 mg L(-1) LAS was promoted by more than 97 %. These results suggested that the increasing LAS would overturn the competition of algae in freshwater ecosystems.

  3. Quality characteristics of rice inoculated with Inonotus obliquus ...

    African Journals Online (AJOL)

    latif

    2013-08-14

    Aug 14, 2013 ... This study was performed to investigate the quality characteristics of Inonotus obliquus mycelia rice incubated with I. obliquus (KCTC 256152). Different volumes of mycelial culture of I. obliquus were used for production of I. obliquus mycelia rice. Twenty percent of the mycelial culture was added to rice and.

  4. Kultivasi Scenedesmus SP. Pada Medium Air Limbah

    OpenAIRE

    Kawaroe, Mujizat

    2011-01-01

    Proses fotosintesis pada mikroalga membutuhkan CO2 dan cahaya matahari serta nutrien untuk pertumbuhannya. Kultivasi Scenedesmus sp. pada medium air limbah bertujuan guna mencukupi kebutuhan mikroalga akan nutrien dan mengurangi masukan dari bahan kimia yang terkandung dalam air limbah tersebut ke lingkungan. Kultivasi Scenedesmus sp. dilakukan selama tujuh hari pada medium air limbah industri tanpa penambahan nutri...

  5. New records of Scenedesmus Meyen from China

    Directory of Open Access Journals (Sweden)

    ZHU Yaru

    2012-08-01

    Full Text Available One species,four variant and one forma of Chlorophyta Scenedesmus are first reported in China,they are Scenedesmus ecornis var.disciformis,S.acutus f.alternans,S.ginzbergeri,S.intermedius var. bicaudatus,S.opoliensis var. polycostatus and S.opoliensis var.bicaudatus.The taxonomic characters were described for each taxon by micro-photography and pictures.

  6. Detection and imaging of lipids ofScenedesmus obliquusbased on confocal Raman microspectroscopy.

    Science.gov (United States)

    Shao, Yongni; Fang, Hui; Zhou, Hong; Wang, Qi; Zhu, Yiming; He, Yong

    2017-01-01

    In this study, confocal Raman microspectroscopy was used to detect lipids in microalgae rapidly and non-destructively. Microalgae cells were cultured under nitrogen deficiency. The accumulation of lipids in Scenedesmus obliquus was observed by Nile red staining, and the total amount of lipids accumulated in the cells was measured by gravimetric method. The signals from different microalgae cells were collected by confocal Raman microspectroscopy to establish a prediction model of intracellular lipid content, and surface scanning signals for drawing pseudo color images of lipids distribution. The images can show the location of pyrenoid and lipid accumulation in cells. Analyze Raman spectrum data and build PCA-LDA model using four different bands (full bands, pigments, lipids, and mixed features). Models of full bands or pigment characteristic bands were capable of identifying S. obliquus cells under different nitrogen stress culture time. The prediction accuracy of model of lipid characteristic bands is relatively low. The correlation between the fatty acid content measured by the gravimetric method and the integral Raman intensity of the oil characteristic peak (1445 cm -1 ) measured by Raman spectroscopy was analyzed. There was significant correlation ( R 2  = 0.83), which means that Raman spectroscopy is applicable to semi-quantitative detection of microalgal lipid content.

  7. Antitumor and immunomodulatory activity of Inonotus obliquus

    Directory of Open Access Journals (Sweden)

    Staniszewska Justyna

    2017-06-01

    Full Text Available The article presents the antitumor and immunomodulatory activity of compounds and extracts from Inonotus obliquus. Polysaccharides isolated from sclerotium have a direct antitumor effect due to protein synthesis inhibition in tumor cells. Polysaccharides derived from the mycelium function by activating the immune system. Due to the limited toxicity of these substances, both extracts as well as isolated and purified chemicals may be a good alternative to current chemotherapy and play a role in cancer prevention. In vitro experiments have shown the inhibition of inflammation with the influence of action of I. obliquus extracts; however, in vivo experiments on animals implanted with tumor cells of different types have shown the activation of the host immune system. This led to decrease in tumor mass and prolonged survival. The immunomodulatory mechanism of action is complex and it seems that stimulation of macrophages and induction of apoptosis in cancer cells is of great importance.

  8. Comparative analyses of chloroplast genome data representing nine green algae in Sphaeropleales (Chlorophyceae, Chlorophyta

    Directory of Open Access Journals (Sweden)

    Karolina Fučíková

    2016-06-01

    Full Text Available The chloroplast genomes of green algae are highly variable in their architecture. In this article we summarize gene content across newly obtained and published chloroplast genomes in Chlorophyceae, including new data from nine of species in Sphaeropleales (Chlorophyceae, Chlorophyta. We present genome architecture information, including genome synteny analysis across two groups of species. Also, we provide a phylogenetic tree obtained from analysis of gene order data for species in Chlorophyceae with fully sequenced chloroplast genomes. Further analyses and interpretation of the data can be found in “Chloroplast phylogenomic data from the green algal order Sphaeropleales (Chlorophyceae, Chlorophyta reveal complex patterns of sequence evolution” (Fučíková et al., In review [1].

  9. Productivity and biochemical composition of Tetradesmus obliquus and Phaeodactylum tricornutum

    NARCIS (Netherlands)

    Buono, Silvia; Colucci, Antonella; Angelini, Antonella; Langellotti, Antonio Luca; Massa, Marina; Martello, Anna; Fogliano, Vincenzo; Dibenedetto, Angela

    2016-01-01

    The present work evaluated biomass productivity, carbon dioxide fixation rate, and biochemical composition of two microalgal species, Phaeodactylum tricornutum (Bacillariophyta) and Tetradesmus obliquus (Chlorophyta), cultivated indoors in high-technology photobioreactors (HT-PBR) and outdoors

  10. Carotenoid distribution in living cells of Haematococcus pluvialis (Chlorophyceae.

    Directory of Open Access Journals (Sweden)

    Aaron M Collins

    Full Text Available Haematococcus pluvialis is a freshwater unicellular green microalga belonging to the class Chlorophyceae and is of commercial interest for its ability to accumulate massive amounts of the red ketocarotenoid astaxanthin (3,3'-dihydroxy-β,β-carotene-4,4'-dione. Using confocal Raman microscopy and multivariate analysis, we demonstrate the ability to spectrally resolve resonance-enhanced Raman signatures associated with astaxanthin and β-carotene along with chlorophyll fluorescence. By mathematically isolating these spectral signatures, in turn, it is possible to locate these species independent of each other in living cells of H. pluvialis in various stages of the life cycle. Chlorophyll emission was found only in the chloroplast whereas astaxanthin was identified within globular and punctate regions of the cytoplasmic space. Moreover, we found evidence for β-carotene to be co-located with both the chloroplast and astaxanthin in the cytosol. These observations imply that β-carotene is a precursor for astaxanthin and the synthesis of astaxanthin occurs outside the chloroplast. Our work demonstrates the broad utility of confocal Raman microscopy to resolve spectral signatures of highly similar chromophores in living cells.

  11. Carotenoid Distribution in Living Cells of Haematococcus pluvialis (Chlorophyceae)

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Aaron M.; Jones, Howland D. T.; Han, Danxiang; Hu, Qiang; Beechem, Thomas E.; Timlin, Jerilyn A.; Evens, Terence

    2011-09-06

    Haematococcus pluvialis is a freshwater unicellular green microalga belonging to the class Chlorophyceae and is of commercial interest for its ability to accumulate massive amounts of the red ketocarotenoid astaxanthin (3,3'-dihydroxy-β,β-carotene-4,4'-dione). Using confocal Raman microscopy and multivariate analysis, we demonstrate the ability to spectrally resolve resonance–enhanced Raman signatures associated with astaxanthin and β-carotene along with chlorophyll fluorescence. By mathematically isolating these spectral signatures, in turn, it is possible to locate these species independent of each other in living cells of H. pluvialis in various stages of the life cycle. Chlorophyll emission was found only in the chloroplast whereas astaxanthin was identified within globular and punctate regions of the cytoplasmic space. Moreover, we found evidence for β-carotene to be co-located with both the chloroplast and astaxanthin in the cytosol. These observations imply that β-carotene is a precursor for astaxanthin and the synthesis of astaxanthin occurs outside the chloroplast. Finally, our work demonstrates the broad utility of confocal Raman microscopy to resolve spectral signatures of highly similar chromophores in living cells.

  12. The use of natural infochemicals for sustainable and efficient harvesting of the microalgae Scenedesmus spp. for biotechnology: insights from a meta-analysis.

    Science.gov (United States)

    Roccuzzo, Sebastiana; Beckerman, Andrew P; Pandhal, Jagroop

    2016-12-01

    Open raceway ponds are regarded as the most economically viable option for large-scale cultivation of microalgae for low to mid-value bio-products, such as biodiesel. However, improvements are required including reducing the costs associated with harvesting biomass. There is now a growing interest in exploiting natural ecological processes within biotechnology. We review how chemical cues produced by algal grazers induce colony formation in algal cells, which subsequently leads to their sedimentation. A statistical meta-analysis of more than 80 studies reveals that Daphnia grazers can induce high levels of colony formation and sedimentation in Scenedesmus obliquus and that these natural, infochemical induced sedimentation rates are comparable to using commercial chemical equivalents. These data suggest that natural ecological interactions can be co-opted in biotechnology as part of a promising, low energy and clean harvesting method for use in large raceway systems.

  13. Access the toxic effect of the antibiotic cefradine and its UV light degradation products on two freshwater algae.

    Science.gov (United States)

    Chen, J Q; Guo, R X

    2012-03-30

    Two common freshwater algae Microcystis aeruginosa and Scenedesmus obliquus were employed as test organism to evaluate the toxic effects of the widely used antibiotic, cefradine. In general, cefradine had significantly toxic effect on population growth and chlorophyll-a accumulation of two algae and the cyanophyceae was more sensitive than the chlorophyceae. In addition, cefradine UV light degraded products had adverse effect on M. aeruginosa's growth and chlorophyll-a accumulation. In comparison, even if S. obliquus had growth ability when exposed to cefradine UV light-degradation products, the algal photosynthesis function was also disrupted. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Chloroplast DNA sequence of the green alga Oedogonium cardiacum (Chlorophyceae: Unique genome architecture, derived characters shared with the Chaetophorales and novel genes acquired through horizontal transfer

    Directory of Open Access Journals (Sweden)

    Lemieux Claude

    2008-06-01

    Full Text Available Abstract Background To gain insight into the branching order of the five main lineages currently recognized in the green algal class Chlorophyceae and to expand our understanding of chloroplast genome evolution, we have undertaken the sequencing of chloroplast DNA (cpDNA from representative taxa. The complete cpDNA sequences previously reported for Chlamydomonas (Chlamydomonadales, Scenedesmus (Sphaeropleales, and Stigeoclonium (Chaetophorales revealed tremendous variability in their architecture, the retention of only few ancestral gene clusters, and derived clusters shared by Chlamydomonas and Scenedesmus. Unexpectedly, our recent phylogenies inferred from these cpDNAs and the partial sequences of three other chlorophycean cpDNAs disclosed two major clades, one uniting the Chlamydomonadales and Sphaeropleales (CS clade and the other uniting the Oedogoniales, Chaetophorales and Chaetopeltidales (OCC clade. Although molecular signatures provided strong support for this dichotomy and for the branching of the Oedogoniales as the earliest-diverging lineage of the OCC clade, more data are required to validate these phylogenies. We describe here the complete cpDNA sequence of Oedogonium cardiacum (Oedogoniales. Results Like its three chlorophycean homologues, the 196,547-bp Oedogonium chloroplast genome displays a distinctive architecture. This genome is one of the most compact among photosynthetic chlorophytes. It has an atypical quadripartite structure, is intron-rich (17 group I and 4 group II introns, and displays 99 different conserved genes and four long open reading frames (ORFs, three of which are clustered in the spacious inverted repeat of 35,493 bp. Intriguingly, two of these ORFs (int and dpoB revealed high similarities to genes not usually found in cpDNA. At the gene content and gene order levels, the Oedogonium genome most closely resembles its Stigeoclonium counterpart. Characters shared by these chlorophyceans but missing in members

  15. Phytochemical analysis of Cyrtanthus obliquus bulbs from the ...

    African Journals Online (AJOL)

    Background: Cyrtanthus obliquus is a medicinal plant commonly known by the locals in South Africa as Umathunga. It is used in traditional South African medicine for the treatment of scrofula, chronic coughs and headaches and is also used to prepare the popular decoction known as Imbiza. Materials and methods: The ...

  16. Phytochemical analysis of Cyrtanthus obliquus bulbs from the ...

    African Journals Online (AJOL)

    Proff.Adewunmi

    PHYTOCHEMICAL ANALYSIS OF CYRTANTHUS OBLIQUUS BULBS FROM THE INFORMAL STREET. MARKET OF KWAZULU-NATAL, SOUTH AFRICA. Nomfundo T. ..... traditional herbal medicines, some mycotoxins, naphthalene and styrene. IARC Press: France. pp. 43 – 68. 13. Mander, M. (1998). Marketing of ...

  17. Influence of carbon dioxide, temperature, medium kind and light intensity on the growth of algae Chlamydomonas reinhardtii and Scenedesmus obliquus

    OpenAIRE

    Olejnik Przemysław Piotr; Lewicki Andrzej; Boniecki Piotr; Lewicka Aleksandra; Janczak Damian; Czekała Wojciech

    2016-01-01

    Microalgae attracts the attention of scientists because of the possibility of using in the energy industry as one of the substrates for the production of renewable energy. So far, the greatest emphasis was put on attempts to obtain strains, and technologies of their culturing, in order to efficiently acquire fat from cells and its further conversion to biodiesel using transesterification reaction. Increasingly, algae are considered also as an efficient biomass producer, which can be used as a...

  18. Effect of Nano-Al2O3 on the Toxicity and Oxidative Stress of Copper towards Scenedesmus obliquus

    OpenAIRE

    Xiaomin Li; Suyang Zhou; Wenhong Fan

    2016-01-01

    Nano-Al2O3 has been widely used in various industries; unfortunately, it can be released into the aquatic environment. Although nano-Al2O3 is believed to be of low toxicity, it can interact with other pollutants in water, such as heavy metals. However, the interactions between nano-Al2O3 and heavy metals as well as the effect of nano-Al2O3 on the toxicity of the metals have been rarely investigated. The current study investigated copper toxicity in the presence of nano-Al2O3 towards Scenedesm...

  19. Effect of light intensity, pH, and temperature on triacylglycerol (TAG) accumulation induced by nitrogen starvation in Scenedesmus obliquus

    NARCIS (Netherlands)

    Breuer, G.; Lamers, P.P.; Martens, D.E.; Draaisma, R.B.; Wijffels, R.H.

    2013-01-01

    Microalgae-derived lipids in the form of triacylglycerols (TAGs) are considered an alternative resource for the production of biofuels and food commodities. Large scale production of microalgal TAGs is currently uneconomical. The cost price could be reduced by improving the areal and volumetric TAG

  20. Quality characteristics of rice inoculated with Inonotus obliquus ...

    African Journals Online (AJOL)

    The higher contents for β-1,3-glucan, betulin, polyphenol, and DPPH radical scavenging were found in 30% mycelial culture treatment, showing the best condition for the production of I. obliquus mycelia. Aspartic acid (10.28 to 29.44 μg/100 g), threonine (5.43 to 11.00 μg/100 g), serine (8.84 to 14.53 μg/100 g), glutamic acid ...

  1. Chemical characterization and biological activity of Chaga (Inonotus obliquus) a medicinal "mushroom"

    NARCIS (Netherlands)

    Glamoclija, J.; Ciric, A.; Nikolic, M.; Fernandes, A.; Barros, L.; Calhelha, R.C.; Ferreira, I.C.F.R.; Sokovic, M.; Griensven, van L.J.L.D.

    2015-01-01

    ETHNOPHARMACOLOGICAL RELEVANCE: In Russian traditional medicine, an extract from the mushroom Inonotus obliquus (Fr.) Pil´at is used as an anti-tumor medicine and diuretic. It has been reported that Inonotus obliquus has therapeutic effects, such as anti-inflammatory, immuno-modulatory and

  2. Plastomes of the green algae Hydrodictyon reticulatum and Pediastrum duplex (Sphaeropleales, Chlorophyceae

    Directory of Open Access Journals (Sweden)

    Hilary A. McManus

    2017-05-01

    Full Text Available Background Comparative studies of chloroplast genomes (plastomes across the Chlorophyceae are revealing dynamic patterns of size variation, gene content, and genome rearrangements. Phylogenomic analyses are improving resolution of relationships, and uncovering novel lineages as new plastomes continue to be characterized. To gain further insight into the evolution of the chlorophyte plastome and increase the number of representative plastomes for the Sphaeropleales, this study presents two fully sequenced plastomes from the green algal family Hydrodictyaceae (Sphaeropleales, Chlorophyceae, one from Hydrodictyon reticulatum and the other from Pediastrum duplex. Methods Genomic DNA from Hydrodictyon reticulatum and Pediastrum duplex was subjected to Illumina paired-end sequencing and the complete plastomes were assembled for each. Plastome size and gene content were characterized and compared with other plastomes from the Sphaeropleales. Homology searches using BLASTX were used to characterize introns and open reading frames (orfs ≥ 300 bp. A phylogenetic analysis of gene order across the Sphaeropleales was performed. Results The plastome of Hydrodictyon reticulatum is 225,641 bp and Pediastrum duplex is 232,554 bp. The plastome structure and gene order of H. reticulatum and P. duplex are more similar to each other than to other members of the Sphaeropleales. Numerous unique open reading frames are found in both plastomes and the plastome of P. duplex contains putative viral protein genes, not found in other Sphaeropleales plastomes. Gene order analyses support the monophyly of the Hydrodictyaceae and their sister relationship to the Neochloridaceae. Discussion The complete plastomes of Hydrodictyon reticulatum and Pediastrum duplex, representing the largest of the Sphaeropleales sequenced thus far, once again highlight the variability in size, architecture, gene order and content across the Chlorophyceae. Novel intron insertion sites and unique

  3. Plastocyanin microheterogeneity in Scenedesmus acutus MT8.

    Science.gov (United States)

    Dimitrov, Mitko I; Donchev, Anthony A; Toromanov, Georgi R; Getov, Vladimir I; Toncheva-Panova, Tonka G

    2008-10-01

    Two total plastocyanin (PC) fractions - loosely bound (lPC) and strongly bound (sPC) were extracted (84% and 16%, respectively) from the homogenate of Scenedesmus acutus MT8. Two-fold isolation-purification procedure including DE-52 chromatography separated IPC into a smaller oxidized [IPC (II)] and a larger reduced [IPC(I)] fractions, in contrast to sPC, where sPC(ll) greatly dominated over sPC(I). Analytical isoelectric focusing (IEF) separated IPC(II) into two main fractions only in the presence of 8 M urea, implying microheterogeneity. Preparative IEF in immobiline pH-gradient of 3.2-4.1 separated IPC(II) into two blue fractions - a more alkaline IPC(II) and a more acidic IPC"(II), which were probably stereoisomers. Their UV-Vis spectra exhibited rarely observed tryptophane (291.5 nm) and some differences at 270 and 287 nm. The exact molecular masses of apo-/holo-lPC (10131 Da/10194 Da) were determined by mass spectrometry. The number of -SH groups was determined from the mass difference between alkylated with 4-vinylpyridine (4-VP) and non-alkylated protein. Additionally, a simple procedure for simultaneous separation of both primary structure and stereoisomers of PC was developed.

  4. Empleo de microalga Scenedesmus obliquas en la eliminación de cromo presente en aguas residuales galvánicas

    Directory of Open Access Journals (Sweden)

    Pellón, A.

    2003-02-01

    Full Text Available Dumping wastewaters from plating industry with a high content in chromium is a potential hazard for people and environment. It is known that some metals, including the heavy metals, at low concentrations participate in different metabolic routes, but at high concentration are toxic for many living organisms. Some microorganism taking the heavy metals from the environment are capable of concentrating and accumulating large quantities of them in different citoplasmatic structures with no-toxic effects. Microalgae have affinity by the polyvalent metals making possible their use as depollutant agent in waters that contains dissolved metallic ions as alternative methods when others methods of recycle are unusable. In this report a chromium removal study from a plating wastewater, using scenedesmus obliquus culture was made. The removal efficiency of Cr (VI was 12 % and Cr (III was 27 % and for condition of algae's immobilization removal of Cr (III was 95 %.

    El vertido de aguas residuales con alto contenido de cromo, procedentes de las industrias galvanoplásticas, es un peligro potencial que se le presenta a la población y al medio ambiente. Se conoce que algunos metales, incluyendo los pesados, a concentraciones bajas participan en diferentes rutas metabólicas, pero en altas concentraciones pueden ser tóxicos para muchos organismos vivos. Algunos microorganismos toman los metales pesados del medio ambiente, siendo capaces de concentrar y acumular grandes cantidades de los mismos en diferentes estructuras citoplasmáticas, sin que lleguen a ocasionar efectos tóxicos en los mismos. Las microalgas son un ejemplo de este comportamiento, ya que tienen afinidad por los metales polivalentes, de ahí la posibilidad de su aplicación como agentes descontaminantes en aguas que contengan iones metálicos disueltos como método alternativo cuando no se pueda utilizar otro método de recuperación. En este trabajo se realizó un estudio de

  5. Growth rate of Scenedesmus acutus in laboratory cultures exposed ...

    African Journals Online (AJOL)

    ... examined in unialgal cultures of freshwater green algae, Scenedesmus acutus through 96 h acute toxicity tests. S. acutus was exposed to different concentrations of diazinon (1, 2, 4, 8, 16 and 32 μl) in the laboratory maintained at 23 ± 1°C and 16:8 light : dark regime. Cell numbers were determined daily and growth rates ...

  6. Anaerobic Co-Digestion of the Microalgae Scenedesmus Sp.

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Suarez, J. L.; Carreras, N.

    2011-06-07

    Microalgae biomass has been widely studied for biogas production over the last years and results show that anaerobic digestion is often limited by the low C/N ratio of this type of biomass. Therefore, codigestion with substrates of high C/N ratio is necessary. The objectives of this study are to set up an experimental method that ease reproducibility and control of anaerobic digestion processes in laboratory conditions and to determine the biodegradability and biogas production potential of the co-digestion process of microalgae Scenedesmus sp. and energy crop Opuntia ficus indica (L.) Miller. Results obtained showed that higher C/N ratios are preferred in order to maximize methane production. Highest methane yield obtained was 0.252m3CH4/Kg VS and degradability expressed as percentage COD reduced is around 30% for the ideal mixture found, made up of 75% O. ficus-indica and 25% Scenedesmus sp. in VS basis. A laboratory setup using MicroOxymax respirometer, after its adaptation to work under anaerobic conditions, can be used for the monitoring of anaerobic digestion processes. Scenedesmus sp. as sole substrate for anaerobic digestion does not give good results due to low C/N ratio. However, when codigesting it with O. ficus-indica methane production is satisfactory. Best mixture was made up of 75% O. ficus-indica and 25% Scenedesmus sp. in VS basis. (Author)

  7. Sedimentation losses of Scenedesmus in relation to mixing depth

    NARCIS (Netherlands)

    Visser, PM; Massaut, L; Mur, LR

    In Lake Nieuwe Meer, artificial mixing led to replacement of cyanobacterial dominance by a dominance of non-buoyant algae. In this study, sedimentation losses of Scenedesmus in the mixed lake are compared with those in the stratified lake. Sedimentation losses were much lower in the mixed lake and

  8. Life history and culture studies of Monostroma oxyspermum (Kutz.) Doty (Monostromataceae, Chlorophyceae) growing in estuarine conditions along the central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Deshmukhe, G.V.; Dhargalkar, V.K.; Untawale, A.G.

    The specimen of Monostroma oxyspermum (Chlorophyceae) were collected in Indian waters from mangrove ecosystem of Shirgao Creek, Ratnagiri, Maharashtra; Terekhol Creek, Goa; and Kali Estuary, Karwar Karnataka. The life history of these were studied...

  9. Effect of isomers of hydroxybenzoic acid on the growth and metabolism of Chlorella vulgaris Beijerinck (Chlorophyceae

    Directory of Open Access Journals (Sweden)

    Andrzej Bajguz

    2014-01-01

    Full Text Available The isomers o-, m-, and p- of hydroxybenzoic acid (HBA in the concentration range 10-1-10-4 M in the unicellular green alga Chlorella vulgaris (Chlorophyceae display marked biological activity. The o-HBA isomer, commonly known as salicylic acid, in a concentration of 10-4 M exerted the most stimulating effect on the parameters analysed (the number of cells, dry mass, the content of chlorophylls a and h, carotenoids, soluble proteins and their secretion, monosaccharides, DNA and RNA whereas p-HBA had weak stimulating properties. On the other hand, m-HBA had a weak inhibitory effect on the growth of C. vulgaris and all the biochemical parameters analysed in comparison with the control culture of algae devoid of HBA isomers.

  10. Colony formation in Scenedesmus: No contribution of urea in induction by a lipophilic Daphnia exudate

    OpenAIRE

    Lurling, M.F.L.L.W.; Elert, von, E.

    2001-01-01

    The common green alga Scenedesmus may respond morphologically to numerous environmental factors. The formation of colonies in Scenedesmus resulting from exposure to grazer (Daphnia) excreta is of particular interest since the induced colony formation may be an induced defense. Recent studies suggested that unicell-colony transformation in Scenedesmus could result from urea released by actively feeding Daphnia and/or by a more lipophilic substance that could be retained by lipophilic solid pha...

  11. Growth of microalgae Scenedesmus sp in ethanol vinasse

    OpenAIRE

    Ramirez, Nelzy Neyza Vargas; Farenzena, Marcelo; Trierweiler, Jorge Otávio

    2014-01-01

    This study evaluated the feasibility of using vinasse as a nutrient source for microalgae cultivation. The Scenedesmus sp was grown in a medium supplemented with vinasse and process variables were optimized using a factorial design and a Central Composite Design (CCD). The factorial design results showed that it was possible to cultivate microalgae at concentrations of up to 40% of vinasse in the culture medium. The CCD results showed that the light intensity and vinasse concentration influen...

  12. Phycoremediation of Tannery Wastewater Using Microalgae Scenedesmus Species.

    Science.gov (United States)

    Ajayan, Kayil Veedu; Selvaraju, Muthusamy; Unnikannan, Pachikaran; Sruthi, Palliyath

    2015-01-01

    A number of microalgae species are efficient in removing toxicants from wastewater. Many of these potential species are a promising, eco-friendly, and sustainable option for tertiary wastewater treatment with a possible advantage of improving the economics of microalgae cultivation for biofuel production. The present study deals with the phycoremediation of tannery wastewater (TWW) using Scenedesmus sp. isolated from a local habitat. The test species was grown in TWW under laboratory conditions and harvested on the 12th day. The results revealed that the algal biomass during the growth period not only reduced the pollution load of heavy metals (Cr-81.2-96%, Cu-73.2-98%, Pb-75-98% and Zn-65-98%) but also the nutrients (NO3 >44.3% and PO4 >95%). Fourier Transform Infrared (FTIR) spectrums of Scenedesmus sp. biomass revealed the involvement of hydroxyl amino, carboxylic and carbonyl groups. The scanning electron micrograph (SEM) and Energy Dispersive X-ray Spectroscopic analysis (EDS) revealed the surface texture, morphology and element distribution of the biosorbent. Furthermore, the wastewater generated during wet-blue tanning process can support dense population of Scenedesmus sp., making it a potential growth medium for biomass production of the test alga for phycoremediation of toxicants in tannery wastewaters.

  13. Colony formation in Scenedesmus: No contribution of urea in induction by a lipophilic Daphnia exudate

    NARCIS (Netherlands)

    Lurling, M.F.L.L.W.; Elert, von E.

    2001-01-01

    The common green alga Scenedesmus may respond morphologically to numerous environmental factors. The formation of colonies in Scenedesmus resulting from exposure to grazer (Daphnia) excreta is of particular interest since the induced colony formation may be an induced defense. Recent studies

  14. Colony formation in Scenedesmus: no contribution of urea in induction by a lipophilic Daphnia exudate

    NARCIS (Netherlands)

    Lürling, M.; Von Elert, E.

    2001-01-01

    The common green alga Scenedesmus may respond morphologically to numerous environmental factors. The formation of colonies in Scenedesmus resulting from exposure to grazer (Daphnia) excreta is of particular interest since the induced colony formation may be an induced defense. Recent studies

  15. Accurate and robust phylogeny estimation based on profile distances: a study of the Chlorophyceae (Chlorophyta

    Directory of Open Access Journals (Sweden)

    Rahmann Sven

    2004-06-01

    Full Text Available Abstract Background In phylogenetic analysis we face the problem that several subclade topologies are known or easily inferred and well supported by bootstrap analysis, but basal branching patterns cannot be unambiguously estimated by the usual methods (maximum parsimony (MP, neighbor-joining (NJ, or maximum likelihood (ML, nor are they well supported. We represent each subclade by a sequence profile and estimate evolutionary distances between profiles to obtain a matrix of distances between subclades. Results Our estimator of profile distances generalizes the maximum likelihood estimator of sequence distances. The basal branching pattern can be estimated by any distance-based method, such as neighbor-joining. Our method (profile neighbor-joining, PNJ then inherits the accuracy and robustness of profiles and the time efficiency of neighbor-joining. Conclusions Phylogenetic analysis of Chlorophyceae with traditional methods (MP, NJ, ML and MrBayes reveals seven well supported subclades, but the methods disagree on the basal branching pattern. The tree reconstructed by our method is better supported and can be confirmed by known morphological characters. Moreover the accuracy is significantly improved as shown by parametric bootstrap.

  16. Molecular systematics of Volvocales (Chlorophyceae, Chlorophyta) based on exhaustive 18S rRNA phylogenetic analyses.

    Science.gov (United States)

    Nakada, Takashi; Misawa, Kazuharu; Nozaki, Hisayoshi

    2008-07-01

    The taxonomy of Volvocales (Chlorophyceae, Chlorophyta) was traditionally based solely on morphological characteristics. However, because recent molecular phylogeny largely contradicts the traditional subordinal and familial classifications, no classification system has yet been established that describes the subdivision of Volvocales in a manner consistent with the phylogenetic relationships. Towards development of a natural classification system at and above the generic level, identification and sorting of hundreds of sequences based on subjective phylogenetic definitions is a significant step. We constructed an 18S rRNA gene phylogeny based on 449 volvocalean sequences collected using exhaustive BLAST searches of the GenBank database. Many chimeric sequences, which can cause fallacious phylogenetic trees, were detected and excluded during data collection. The results revealed 21 strongly supported primary clades within phylogenetically redefined Volvocales. Phylogenetic classification following PhyloCode was proposed based on the presented 18S rRNA gene phylogeny along with the results of previous combined 18S and 26S rRNA and chloroplast multigene analyses.

  17. Investigation of three lignin complexes with antioxidant and immunological capacities from Inonotus obliquus.

    Science.gov (United States)

    Niu, Hong; Song, Dan; Mu, Haibo; Zhang, Wuxia; Sun, Feifei; Duan, Jinyou

    2016-05-01

    Mushroom Inonotus obliquus (I. obliquus), a folk medicine, has been widely used to treat several human malicious tumors since 16th century. In this study, three homogenous biomolecules (designated IOA1, IOA2 and IOA3) were prepared from the alkali extract of I. obliquus. Their molecular weights were measured to be 6.1 × 10(4), 2.9 × 10(4) and 3.5 × 10(4) g/mol respectively and all of them were characterized as lignin-carbohydrate complexes mainly comprised lignin as well as -25% carbohydrates. Antioxidant assays indicated that all of them exhibited pronounced reductive power and strong scavenging activities on DPPH and hydroxyl radicals in vitro. Immunological tests showed that they could also significantly stimulate nitric oxide production and phagocytic activity in RAW 264.7 macrophages. These results implied that the lignin-carbohydrate complexes extracted from I. obliquus might be used as novel natural antioxidants or immunostimulants in functional foods or pharmaceutical candidates. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Fossil Scenedesmus (Chlorococcales) from the Raton Formation, Colorado and New Mexico, U.S.A.

    Science.gov (United States)

    Farley, Fleming R.

    1989-01-01

    Fossilized coenobia of the alga Scenedesmus (Chlorococcales) were recovered in palynomorph assemblages from a lower Paleocene mudstone in the Upper Cretaceous and Paleocene Raton Formation of Colorado and New Mexico. This is the first description of fossil Scenedesmus from Tertiary rocks. Two species, Scenedesmus tschudyi sp. nov. and Scenedesmus hanleyi sp. nov., are present in the assemblages. Coenobia of S. tschudyi sp. nov. are characterized by lunate terminal cells and fusiform median cells. As in species of modern Scenedesmus, coenobia of S. tschudyi sp. nov. occur with four or eight cells. Coenobia of S. hanleyi sp. nov. have four oval cells and are smaller than coenobia of S. tschudyi sp. nov. Fossil coenobia of Scenedesmus co-occur with the fossil alga Pediastrum in Raton Formation mudstones. Because these genera co-occur in modern lakes and ponds, the co-occurrence of fossil Scenedesmus and Pediastrum in ancient nonmarine rocks is interpreted to indicate deposition of sediment in freshwater lakes and ponds. ?? 1989.

  19. Proliferation of group II introns in the chloroplast genome of the green alga Oedocladium carolinianum (Chlorophyceae

    Directory of Open Access Journals (Sweden)

    Jean-Simon Brouard

    2016-10-01

    Full Text Available Background The chloroplast genome sustained extensive changes in architecture during the evolution of the Chlorophyceae, a morphologically and ecologically diverse class of green algae belonging to the Chlorophyta; however, the forces driving these changes are poorly understood. The five orders recognized in the Chlorophyceae form two major clades: the CS clade consisting of the Chlamydomonadales and Sphaeropleales, and the OCC clade consisting of the Oedogoniales, Chaetophorales, and Chaetopeltidales. In the OCC clade, considerable variations in chloroplast DNA (cpDNA structure, size, gene order, and intron content have been observed. The large inverted repeat (IR, an ancestral feature characteristic of most green plants, is present in Oedogonium cardiacum (Oedogoniales but is lacking in the examined members of the Chaetophorales and Chaetopeltidales. Remarkably, the Oedogonium 35.5-kb IR houses genes that were putatively acquired through horizontal DNA transfer. To better understand the dynamics of chloroplast genome evolution in the Oedogoniales, we analyzed the cpDNA of a second representative of this order, Oedocladium carolinianum. Methods The Oedocladium cpDNA was sequenced and annotated. The evolutionary distances separating Oedocladium and Oedogonium cpDNAs and two other pairs of chlorophycean cpDNAs were estimated using a 61-gene data set. Phylogenetic analysis of an alignment of group IIA introns from members of the OCC clade was performed. Secondary structures and insertion sites of oedogonialean group IIA introns were analyzed. Results The 204,438-bp Oedocladium genome is 7.9 kb larger than the Oedogonium genome, but its repertoire of conserved genes is remarkably similar and gene order differs by only one reversal. Although the 23.7-kb IR is missing the putative foreign genes found in Oedogonium, it contains sequences coding for a putative phage or bacterial DNA primase and a hypothetical protein. Intergenic sequences are 1.5-fold

  20. Evaluation of anaerobic digestates from different feedstocks as growth media for Tetradesmus obliquus, Botryococcus braunii, Phaeodactylum tricornutum and Arthrospira maxima

    NARCIS (Netherlands)

    Massa, Marina; Buono, Silvia; Langellotti, Antonio Luca; Castaldo, Luigi; Martello, Anna; Paduano, Antonello; Sacchi, Raffaele; Fogliano, Vincenzo

    2017-01-01

    In this paper, two freshwater microalgae (Tetradesmus obliquus and Botryococcus braunii), a marine diatom (Phaeodactylum tricornutum) and a photosynthetic cyanobacterium (Arthrospira maxima) were investigated for their ability to grow on liquid digestates (LDs). Three LDs were obtained from

  1. Wastewater nutrient removal by Chlorella pyrenoidosa and Scenedesmus sp.

    Science.gov (United States)

    Tam, N F; Wong, Y S

    1989-01-01

    Two different species of photosynthetic microalgae, Chlorella pyrenoidosa and Scenedesmus sp., were grown in settled and activated sewage filtrates at two different inoculum sizes, aimed to reduce nutrient load from wastewater. Higher growth rates were recorded in cultures with higher inoculum size, and algal cells usually grew better in settled sewage than in activated sewage. As algae started to grow and multiply, both nitrogen and phosphorus content in wastewater decreased significantly. The removal rate was rapid during the first week of growth and more than 2/3 of wastewater N and P was reduced. After the initial period, the removal rate slowed down. At the end of this study, more than 80% of total-P and inorganic N present in settled sewage were reduced but such removal efficiency was lower in activated sewage. In general, high inoculum size of algal cells provided more N and P removal than low inoculum, and Chlorella cells performed better than Scenedesmus. These results suggest that cultivation of Chlorella seems to be one of the feasible methods to reduce the amount of nitrogen and phosphorus entering the nearby coastal water, thus preventing the eutrophication problem. It is also clear that algal ponds with high inoculum size might be more suitable to be installed as a secondary rather than a tertiary treatment process.

  2. Effects of different types of herbicides and insecticides on population of green microalgae Scenedesmus quadricauda

    Directory of Open Access Journals (Sweden)

    Ahmadreza Pirali Zefrei

    2017-03-01

    Discussion and conclusion: According to the results of this study, (Scenedesmus quadricauda can be used as a biological indicator in aquatic ecosystems while it needs more extensive and intensive studies.

  3. Domestic wastewater treatment and biofuel production by using microalga Scenedesmus sp. ZTY1.

    Science.gov (United States)

    Zhang, Tian-Yuan; Wu, Yin-Hu; Hu, Hong-Ying

    2014-01-01

    Cultivation of microalgae for biomass production is a promising way to dispose of wastewater and recover nutrients simultaneously. The properties of nutrient removal and biomass production in domestic wastewater of a newly isolated microalga Scenedesmus sp. ZTY1 were investigated in this study. Scenedesmus sp. ZTY1, which was isolated from a wastewater treatment plant in Beijing, grew well in both the primary and secondary effluents of a wastewater treatment plant during the 21-day cultivation, with a maximal algal density of 3.6 × 10(6) and 1.9 × 10(6) cells · mL(-1), respectively. The total phosphorus concentrations in both effluents could be efficiently removed by over 97% after the cultivation. A high removal rate (over 90%) of total nitrogen (TN) was also observed. After cultivation in primary effluent for 21 days, the lipid content of Scenedesmus sp. ZTY1 in dry weight had reached about 32.2%. The lipid and triacylglycerol (TAG) production of Scenedesmus sp. ZTY1 was increased significantly with the extension of cultivation time. The TAG production of Scenedesmus sp. ZTY1 increased from 32 mg L(-1) at 21 d to 148 mg L(-1) at 45 d in primary effluent. All the experiments were carried out in non-sterilized domestic wastewater and Scenedesmus sp. ZTY1 showed good adaptability to the domestic wastewater environment.

  4. Aeration strategy for biofilm cultivation of the microalga Scenedesmus dimorphus.

    Science.gov (United States)

    Ji, Chunli; Wang, Junfeng; Liu, Tianzhong

    2015-10-01

    Biofilm cultivation of microalgae may be useful for biofuel production. However, many aspects for this cultivation method have not been well assessed. Accordingly, aeration strategy for biofilm cultivation of Scenedesmus dimorphus has been explored. Biomass, lipid and triacylglycerol (TAG) productivity in increased S. dimorphus as the CO2 concentration increased within 0.038-0.5% and kept constant with further increases. The biomass, lipid and TAG productivity increased with the speed increasing and an obvious threshold point was observed at 6.6 ml(-2) min(-1). The lipid and TAG content was unaffected by the aeration rate. Both the CO2 concentration as well as aeration speed affected the growth of S. dimorphus in biofilm cultivation. The optimized aeration strategy for biofilm cultivation was continuous air flow enriched with 1% CO2 (v/v) at 6.6 ml(-2) min(-1).

  5. Scenedesmus dimorphus biofilm: Photoefficiency and biomass production under intermittent lighting

    Science.gov (United States)

    Toninelli, Andrea Efrem; Wang, Junfeng; Liu, Mingshen; Wu, Hong; Liu, Tianzhong

    2016-01-01

    This study investigated the effect of intermittent lighting on the growth performances of a Scenedesmus dimorphus biofilm. Flashing light effect (FLE) is common in traditional suspended cultures of microalgae; yet, publications about this phenomenon, in the context of biofilm cultivation, are scarce. In this work we demonstrate that, thanks to intermittent illumination, it is possible for attached cultivations to fulfill FLE, improve photoefficiency and productivity as well as providing protection from photoinhibition using much lower flashing light frequencies than those usually required with suspended cultures. Medium frequency intermittent lighting (0.1 Hz) guaranteed excellent light integration resulting in 9.13 g m−2 d−1 biomass productivity, which was 8.9% higher than with continuous lighting. Results showed that a light fraction value of 0.5 always improved photoefficiency values as related to continuous light with a 118.8% maximum increase. PMID:27561323

  6. Isolation of New Aliphatic Sulfates and Sulfamate as the Daphnia Kairomones Inducing Morphological Change of a Phytoplankton Scenedesmus gutwinskii

    National Research Council Canada - National Science Library

    Yasumoto, Ko; Nishigami, Akinori; Aoi, Hiroaki; Tsuchihashi, Chise; Kasai, Fumie; Kusumi, Takenori; Ooi, Takashi

    2008-01-01

    New aliphatic sulfates and sulfamates were isolated from Daphnia pulex as the Daphnia kairomones that induced morphological defense of a freshwater phytoplankton Scenedesmus gutwinskii var. heterospina (NIES-802...

  7. Effect of salinity stress on growth, lipid productivity, fatty acid composition, and biodiesel properties in Acutodesmus obliquus and Chlorella vulgaris.

    Science.gov (United States)

    Pandit, Priti Raj; Fulekar, Madhusudan H; Karuna, Mallampalli Sri Lakshmi

    2017-05-01

    Two microalgae strains including Chlorella vulgaris and Acutodesmus obliquus were grown on BG11 medium with salinity stress ranging from 0.06 to 0.4 M NaCl. Highest lipid content in C. vulgaris and A. obliquus was 49 and 43% in BG11 amended with 0.4 M NaCl. The microalgal strains C. vulgaris and A. obliquus grow better at 0.06 M NaCl concentration than control condition. At 0.06 M NaCl, improved dry biomass content in C. vulgaris and A. obliquus was 0.92 and 0.68 gL-1, respectively. Stress biomarkers like reactive oxygen species, antioxidant enzyme catalase, and ascorbate peroxidase were also lowest at 0.06 M NaCl concentration revealing that both the microalgal strains are well acclimatized at 0.06 M NaCl concentration. The fatty acid composition of the investigated microalgal strains was also improved by increased NaCl concentration. At 0.4 M NaCl, palmitic acid (37%), oleic acid (15.5%), and linoleic acid (20%) were the dominant fatty acids in C. vulgaris while palmitic acid (54%) and stearic acid (26.6%) were major fatty acids found in A. obliquus. Fatty acid profiling of C. vulgaris and A. obliquus significantly varied with salinity concentration. Therefore, the study showed that salt stress is an effective stress that could increase not only the lipid content but also improved the fatty acid composition which could make C. vulgaris and A. obliquus potential strains for biodiesel production.

  8. Occurrence of non-hydrolysable amides in the macromolecular constituent of Scenedesmus quadricauda cell wall as revealed by 15N NMR: Origin of n-alkylnitriles in pyrolysates of ultralaminae-containing kerogens

    Science.gov (United States)

    Derenne, S.; Largeau, C.; Taulelle, F.

    1993-02-01

    New structures, termed ultralaminae, were recently shown to occur in kerogens from numerous oil shales and source rocks. Morphological and chemical studies revealed that ultralaminae originate from the selective preservation of the non-hydrolysable biomacromolecules (algaenans) building up the thin outer walls of several Chlorophyceae (green microalgae) including the cosmopolitan genera Scenedesmus and Chlorella. The chemical correlation between such algaenans and fossil ultralaminae was mainly based on the production, on pyrolysis, of nitrogen compounds, n-alkylnitriles, with specific distributions depending on the lacustrine or marine origin of the considered samples. In addition, these bioand geopolymers were characterized by quite high N levels. Solid-state 15N NMR was carried out on 15N-enriched algaenan (isolated from Scenesdesmus quadricauda grown with 15NO 3- as sole nitrogen source) and revealed that amides are the most abundant nitrogen groups in this material. Minor amounts of two other nitrogen groups, amines and probably Nalkyl substituted pyrroles (indoles, carbazoles), are also observed. Amines are unlikely to contribute to the macromolecular structure but could simply correspond to trapped compounds. A part of the tentatively identified N-alkyl substituted pyrroles is released during pyrolysis, but a large fraction of these moieties is retained in the insoluble residue while their N-alkyl substituents are eliminated. The predominant amide groups associated with long polymethylenic chains, occurring in S. quadricauda algaenan, are eliminated during pyrolysis and lead, after a fast dehydration, to the formation of n-alkylnitriles. This study provides, to our knowledge, the first example of non-hydrolysable amide moieties in a biomacromolecule. This unusual resistance is probably due to steric protection within the macromolecular network. Such a protection also allows amide groups in chlorophycean algaenans to survive diagenesis and accounts for the

  9. New Design Strategy for Development of Specific Primer Sets for PCR-Based Detection of Chlorophyceae and Bacillariophyceae in Environmental Samples▿ †

    OpenAIRE

    Valiente Moro, Claire; Crouzet, Olivier; Rasconi, Séréna; Thouvenot, Antoine; Coffe, Gérard; Batisson, Isabelle; Bohatier, Jacques

    2009-01-01

    Studying aquatic microalgae is essential for monitoring biodiversity and water quality. We designed new sets of 18S rRNA PCR primers for Chlorophyceae and Bacillariophyceae by using the ARB software and implementing a virtual PCR program. The results of specificity analysis showed that most of the targeted algal families were identified and nontargeted organisms, such as fungi or ciliates, were excluded. These newly developed PCR primer sets were also able to amplify microalgal rRNA genes fro...

  10. Carbon dioxide fixation and lipid storage by Scenedesmus obtusiusculus.

    Science.gov (United States)

    Toledo-Cervantes, Alma; Morales, Marcia; Novelo, Eberto; Revah, Sergio

    2013-02-01

    An indigenous microalga was isolated from the springs in Cuatro Ciénegas, México. It was morphologically identified as Scenedesmus obtusiusculus and cultivated in bubble-column photobioreactors in batch operation mode. This microalga grows at 10% of carbon dioxide (CO(2)) showing a maximum CO(2) fixation rate of 970gm(-3)d(-1). The microalga, without any nutrient limitation, contained 20% of nonpolar lipids with a biomass productivity of 500gm(-3)d(-1) and a maximum biomass concentration of around 6,000gm(-3) at 5% CO(2) and irradiance of 134μmolm(-2)s(-1). Furthermore, it was observed that the microalga stored 55.7% of nonpolar lipids when 5% CO(2) was fed at 0.8vvm and 54.7μmolm(-2)s(-1) under nitrogen starvation. The lipid profile included C16:0, C18:0, C18:1n9t, C18:1n9c, C18:3n6 with a productivity of 200g lipid m(-3)d(-1). Therefore, the microalga may have biotechnological potential producing lipids for biodiesel. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Morpho-physiological effects of ibuprofen on Scenedesmus rubescens.

    Science.gov (United States)

    Moro, Isabella; Matozzo, Valerio; Piovan, Anna; Moschin, Emanuela; Vecchia, Francesca Dalla

    2014-09-01

    The pollution of aquatic bodies by drugs is an emerging environmental problem, because of their extensive use in animal and human context. Ibuprofen, 2-[4-(2-methylpropyl)phenyl]propanoic acid, is the non-steroidal anti-inflammatory drug mainly present both in wastewater and in rivers and lakes in Europe. Since in literature there is little information about the effects of ibuprofen on microalgae, in this paper we presented the results on the effects of this molecule at different concentrations (62.5μgL(-1), 250μgL(-1) and 1000μgL(-1)) on cultures of the freshwater microalga Scenedesmus rubescens (P.J.L. Dangeard) E. Kesslet et al. Ibuprofen effects on the alga were assayed at first through analyses of the growth curve. Moreover, analyses of cell morphology, ultrastructure, and photosynthetic pigments were additionally performed. The first negative effect of the drug was on the microalga growth, suggesting a drug action dose-dependent mechanism type, more evident at the concentration of 1000μgL(-1) ibuprofen and in the last phase of the growth curve. In support of this, following ibuprofen exposure, the cells exhibited morphological and ultrastructural alterations, mainly consisting in large cytoplasmic inclusions, probably of lipids and/or carotenoids. The decrease of chlorophyll amounts and, on the contrary, the increase of carotenoids were correlated with a stressful condition induced by drug. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Evaluation of anaerobic digestates from different feedstocks as growth media for Tetradesmus obliquus, Botryococcus braunii, Phaeodactylum tricornutum and Arthrospira maxima.

    Science.gov (United States)

    Massa, Marina; Buono, Silvia; Langellotti, Antonio Luca; Castaldo, Luigi; Martello, Anna; Paduano, Antonello; Sacchi, Raffaele; Fogliano, Vincenzo

    2017-05-25

    In this paper, two freshwater microalgae (Tetradesmus obliquus and Botryococcus braunii), a marine diatom (Phaeodactylum tricornutum) and a photosynthetic cyanobacterium (Arthrospira maxima) were investigated for their ability to grow on liquid digestates (LDs). Three LDs were obtained from anaerobic digestion of different organic wastes: zootechnical (ZW LD), vegetable biomass (VW LD) and the organic fraction of municipal solid wastes (MW LD). All the strains showed the same growth performance on VW LD as on the respective standard media (SM), while ZW LD was efficient only for growth of T. obliquus and B. braunii. MW LD was the poorest growth medium for all the strains. Data on nutrient removal efficiency showed that A. maxima and T. obliquus made the best use of NH4(+)-N with removal values ranging between 98.9-99.8%, while P. tricornutum and B. braunii showed values of 79.0 and 88.5% respectively. Applying repeated batch cultivation in photobioreactors, the biochemical composition of A. maxima and T. obliquus biomass grown on ZW LD and VW LD, showed an increase of lipid, carbohydrates and ash in both microalgae. Biomass biochemical profiles suggest possible applications in feed, chemicals and energy sectors. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Optimization of hydroxyl radical scavenging activity of exopolysaccharides from Inonotus obliquus in submerged fermentation using response surface methodology

    NARCIS (Netherlands)

    Chen, H.; Xu, X.; Zhu, Y.

    2010-01-01

    The objectives of this study were to investigate the effect of fermentation medium on the hydroxyl radical scavenging activity of exopolysaccharides from Inonotus obliquus by response surface methodology (RSM). A two-level fractional factorial design was used to evaluate the effect of different

  14. Growth of Scenedesmus dimorphus in different algal media and pH ...

    African Journals Online (AJOL)

    This study designates the bold basal medium as advantageous one for S. dimorphus and also reveals that production of metabolites by the same algal strain depends mostly on the nature of constituents of media and might have different influence on the pH. Keywords: Scenedesmus dimorphus, bold basal medium, algal ...

  15. Morphological changes in Scenedesmus induced by infochemicals released in situ from zooplankton grazers

    NARCIS (Netherlands)

    Lürling, M.; Van Donk, E.

    1997-01-01

    Biochemical substances released from Daphnia galeata induced colony formation in the green alga Scenedesmus acutus. Normally this strain consisted mainly of single cells in cultures. However, if exposed for 48 h to either water with live Daphnia or to O.1-mu m filtered water from a culture with

  16. Scenedesmus sp. NJ-1 isolated from Antarctica: a suitable renewable lipid source for biodiesel production.

    Science.gov (United States)

    Chen, Zhuo; Gong, Yangmin; Fang, Xiantao; Hu, Hanhua

    2012-11-01

    Microalgal lipids are promising alternative feedstocks for biodiesel production. Scenedesmus sp. NJ-1, an oil-rich freshwater microalga isolated from Antarctica, was identified to be a suitable candidate to produce biodiesel in this study. This strain could grow at temperatures ranging from 4 to 35 °C. With regular decrease in nitrate concentration in the medium, large quantities of triacylglycerols accumulated under batch culture conditions detected by thin layer chromatography and BODIPY 505/515 fluorescent staining. Scenedesmus sp. NJ-1 achieved the average biomass productivity of 0.105 g l⁻¹ d⁻¹ (dry weight) and nearly the highest lipid content (35 % of dry cell weight) was reached at day 28 in the batch culture. Neutral lipids accounted for 78 % of total lipids, and C18:1 (n-9), C16:0 were the major fatty acids in total lipids, composing 37 and 20 % of total fatty acids of Scenedesmus sp. NJ-1 grown for 36 days, respectively. These results suggested that Scenedesmus sp. NJ-1 was a good source of microalgal oils for biodiesel production.

  17. Influences of external factors on the energy conversion and productivity of Scenedesmus sp. in mass culture

    NARCIS (Netherlands)

    Wesselius, J.C.

    1973-01-01

    Experiments about the influence of external factors on the energy conversion in mass cultures of Scenedesmus are described in this thesis. Several types of culture vessels were used in the laboratory as well as in the open. Demonstration models of Miele washing

  18. Effect of herbicides on photosynthetic electron transport and on the growth of the alga Scenedesmus quadricauda

    Directory of Open Access Journals (Sweden)

    W. Hendrich

    2015-01-01

    Full Text Available The inhibitory effect of herbicides on the Hill reaction (with 2,6-dichloro-phenol-indophenol as acceptor and their influence on development of the alga Scenedesmus quadricauda was studied. The following herbicides were tested: 2,4-D, Gramoxone, Afalon, Kresamone, CIPC and Simazine. The results are discussed in terms of the mechanism of action of the investigated herbicides.

  19. Responses of respiration and photosynthesis of Scenedesmus protuberans Fritsch to gradual and steep salinity increases

    NARCIS (Netherlands)

    Flameling, I.A.; Kromkamp, J.C.

    1994-01-01

    The effect of an increase in salinity on the physiology of the halotolerant chlorophyte Scenedesmus protuberans was studied in light-limited continuous cultures. It was observed that a gradual, as well as a steep increase in salinity resulted in lower biomass. However, the mechanisms by which this

  20. Chemical structure of algaenans from the freshwater algae Tetraedron minimum, Scenedesmus communis and Pediastrum boryanum

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Blokker, P.; Schouten, S.; Ende, H. van den; Hatcher, P.G.

    1998-01-01

    The cell walls of the fresh water green microalgae Tetraedron minimum, Scenedesmus communis and Pediastrum boryanum are composed of highly resistant, non-hydrolyzable aliphatic biopolymers as revealed by 13C-NMR, FTIR and thermal and chemical degradations. The biopolymers are composed of long-chain

  1. Grazer-induced colony formation in Scenedesmus: are there costs to being colonial?

    NARCIS (Netherlands)

    Lürling, M.; Van Donk, E.

    2000-01-01

    Grazer-induced colony formation in the common green alga Scenedesmus acutus may be interpreted as an anti-grazer defense. Costs are to be expected because otherwise the protected colonial morph would be the norm. Analysis of growth rates, light harvesting in terms of photosystem II (PSII) efficiency

  2. Screening and Evaluation of Some Green Algal Strains (Chlorophyceae Isolated from Freshwater and Soda Lakes for Biofuel Production

    Directory of Open Access Journals (Sweden)

    Ramganesh Selvarajan

    2015-07-01

    Full Text Available Microalgae are photosynthetic microorganisms that can produce lipids, proteins and carbohydrates in large amounts and within short periods of time and these can be processed into both biofuels and other useful commercial products. Due to this reason microalgae are considered as a potential source of renewable energy; and one of the most important decisions in obtaining oil from microalgae is the choice of species. In this study, the potential of Chlorophyceae species isolated from freshwater and soda lakes in Hungary and Romania (Central Europe were characterized and evaluated by determining their biomass accumulation, lipid productivity, fatty acid profiles, and biodiesel properties besides protein and carbohydrate productivity. Out of nine strains tested, three accumulated more than 40% dry weight of protein, four accumulated more than 30% dry weight of carbohydrate and the strain Chlorella vulgaris LC8 accumulated high lipid content (42.1% ± 2.6% with a favorable C16-C18 fatty acid profile (77.4% as well as suitable biodiesel properties of high cetane number (57.3, low viscosity (4.7 mm2/s, lower iodine number (75.18 g I2/100 g, relative cloud point (8.8 °C and negative cold filter plugging point (−6.5 °C. Hence the new strain, Chlorella vulgaris LC8 has potential as a feedstock for the production of excellent quality biodiesel.

  3. The effect of hip abduction on the EMG activity of vastus medialis obliquus, vastus lateralis longus and vastus lateralis obliquus in healthy subjects

    Directory of Open Access Journals (Sweden)

    Arakaki Juliano

    2006-07-01

    Full Text Available Abstract Study design Controlled laboratory study. Objectives The purposes of this paper were to investigate (d whether vastus medialis obliquus (VMO, vastus lateralis longus (VLL and vastus lateralis obliquus (VLO EMG activity can be influenced by hip abduction performed by healthy subjects. Background Some clinicians contraindicate hip abduction for patellofemoral patients (with based on the premise that hip abduction could facilitate the VLL muscle activation leading to a VLL and VMO imbalance Methods and measures Twenty-one clinically healthy subjects were involved in the study, 10 women and 11 men (aged X = 23.3 ± 2.9. The EMG signals were collected using a computerized EMG VIKING II, with 8 channels and three pairs of surface electrodes. EMG activity was obtained from MVIC knee extension at 90° of flexion in a seated position and MVIC hip abduction at 0° and 30° with patients in side-lying position with the knee in full extension. The data were normalized in the MVIC knee extension at 50° of flexion in a seated position, and were submitted to ANOVA test with subsequent application of the Bonferroni multiple comparisons analysis test. The level of significance was defined as p ≤ 0.05. Results The VLO muscle demonstrated a similar pattern to the VMO muscle showing higher EMG activity in MVIC knee extension at 90° of flexion compared with MVIC hip abduction at 0° and 30° of abduction for male (p Conclusion The results showed that no selective EMG activation was observed when comparison was made between the VMO, VLL and VLO muscles while performing MVIC hip abduction at 0° and 30° of abduction and MVIC knee extension at 90° of flexion in both male and female subjects. Our findings demonstrate that hip abduction do not facilitated VLL and VLO activity in relation to the VMO, however, this study included only healthy subjects performing maximum voluntary isometric contraction contractions, therefore much remains to be discovered by

  4. Effect of indigo dye effluent on the growth, biomass production and phenotypic plasticity of Scenedesmus quadricauda (Chlorococcales).

    Science.gov (United States)

    Chia, Mathias A; Musa, Rilwan I

    2014-03-01

    The effect of indigo dye effluent on the freshwater microalga Scenedesmus quadricauda ABU12 was investigated under controlled laboratory conditions. The microalga was exposed to different concentrations of the effluent obtained by diluting the dye effluent from 100 to 175 times in bold basal medium (BBM). The growth rate of the microalga decreased as indigo dye effluent concentration increased (p Scenedesmus, which means it can be considered an important biomarker for toxicity testing.

  5. New design strategy for development of specific primer sets for PCR-based detection of Chlorophyceae and Bacillariophyceae in environmental samples.

    Science.gov (United States)

    Moro, Claire Valiente; Crouzet, Olivier; Rasconi, Séréna; Thouvenot, Antoine; Coffe, Gérard; Batisson, Isabelle; Bohatier, Jacques

    2009-09-01

    Studying aquatic microalgae is essential for monitoring biodiversity and water quality. We designed new sets of 18S rRNA PCR primers for Chlorophyceae and Bacillariophyceae by using the ARB software and implementing a virtual PCR program. The results of specificity analysis showed that most of the targeted algal families were identified and nontargeted organisms, such as fungi or ciliates, were excluded. These newly developed PCR primer sets were also able to amplify microalgal rRNA genes from environmental samples with accurate specificity. These tools could be of great interest for studying freshwater microalgal ecology and for developing bioindicators of the health status of aquatic environments.

  6. New Design Strategy for Development of Specific Primer Sets for PCR-Based Detection of Chlorophyceae and Bacillariophyceae in Environmental Samples▿ †

    Science.gov (United States)

    Valiente Moro, Claire; Crouzet, Olivier; Rasconi, Séréna; Thouvenot, Antoine; Coffe, Gérard; Batisson, Isabelle; Bohatier, Jacques

    2009-01-01

    Studying aquatic microalgae is essential for monitoring biodiversity and water quality. We designed new sets of 18S rRNA PCR primers for Chlorophyceae and Bacillariophyceae by using the ARB software and implementing a virtual PCR program. The results of specificity analysis showed that most of the targeted algal families were identified and nontargeted organisms, such as fungi or ciliates, were excluded. These newly developed PCR primer sets were also able to amplify microalgal rRNA genes from environmental samples with accurate specificity. These tools could be of great interest for studying freshwater microalgal ecology and for developing bioindicators of the health status of aquatic environments. PMID:19592531

  7. LED light stress induced biomass and fatty acid production in microalgal biosystem, Acutodesmus obliquus

    Science.gov (United States)

    Choi, Yong-Keun; Kumaran, Rangarajulu Senthil; Jeon, Hyeon Jin; Song, Hak-Jin; Yang, Yung-Hun; Lee, Sang Hyun; Song, Kyung-Guen; Kim, Kwang Jin; Singh, Vijay; Kim, Hyung Joo

    2015-06-01

    Microbial algal system can serve as a potential source for the production of much high value bioproducts and biofuels. The quality and intensity of light are the key elements to optimize the production of algal biomass and fatty acid contents. This study presents the effect of differential LED flashing light conditions on the growth of microalgae, Acutodesmus obliquus. The induced light stress was optimized for its biomass and fatty acid content. The microalgae are exposed to various frequency of intermittent LED flashing light (blue and red lights) at three different phases in the 18 day cell growth (log, lag and stationary phase). The frequency of light flashing rate was adjusted to 120, 10, 5, 3.75, and 1 times per min. The effect of light stress on growth and fatty acids composition of A. obliquus induced an increase in algae growth and fatty acid production. Different optimal timing for light stress was subjected to elucidate the effect of light stress on algae growth and fatty acid production. The results showed an increase in the algae growth (1.2 mg/L of chl a content) under light stress condition at FT10 (flashing time, 10 times per min) from the initial day (log phase) compared with the control experiment (0.4 mg/L of chl a content). However, the total fatty acids (71 mg/g) and volumetric FAME production (9.4 ml/l) level was found to be significant under FT5 (flashing time, 5 times per min), adopting flashing light from day 10 (stationary phase). TEM studies also revealed the deposition of lipid to be largest in the 18 day old cells under flashing light (FT5) condition, representing maximum accumulation of lipids bodies (up to 770 nm diameter in particle size) occupying approximately 42% of the total area of the cell.

  8. LED light stress induced biomass and fatty acid production in microalgal biosystem, Acutodesmus obliquus.

    Science.gov (United States)

    Choi, Yong-Keun; Kumaran, Rangarajulu Senthil; Jeon, Hyeon Jin; Song, Hak-Jin; Yang, Yung-Hun; Lee, Sang Hyun; Song, Kyung-Guen; Kim, Kwang Jin; Singh, Vijay; Kim, Hyung Joo

    2015-06-15

    Microbial algal system can serve as a potential source for the production of much high value bioproducts and biofuels. The quality and intensity of light are the key elements to optimize the production of algal biomass and fatty acid contents. This study presents the effect of differential LED flashing light conditions on the growth of microalgae, Acutodesmus obliquus. The induced light stress was optimized for its biomass and fatty acid content. The microalgae are exposed to various frequency of intermittent LED flashing light (blue and red lights) at three different phases in the 18 day cell growth (log, lag and stationary phase). The frequency of light flashing rate was adjusted to 120, 10, 5, 3.75, and 1 times per min. The effect of light stress on growth and fatty acids composition of A. obliquus induced an increase in algae growth and fatty acid production. Different optimal timing for light stress was subjected to elucidate the effect of light stress on algae growth and fatty acid production. The results showed an increase in the algae growth (1.2mg/L of chl a content) under light stress condition at FT10 (flashing time, 10 times per min) from the initial day (log phase) compared with the control experiment (0.4 mg/L of chl a content). However, the total fatty acids (71 mg/g) and volumetric FAME production (9.4 ml/l) level was found to be significant under FT5 (flashing time, 5 times per min), adopting flashing light from day 10 (stationary phase). TEM studies also revealed the deposition of lipid to be largest in the 18 day old cells under flashing light (FT5) condition, representing maximum accumulation of lipids bodies (up to 770 nm diameter in particle size) occupying approximately 42% of the total area of the cell. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Effect of phytohormones on the growth of Scenedesmus quadricauda (Turp. Bréh

    Directory of Open Access Journals (Sweden)

    Ewa Tatkowska

    2014-01-01

    Full Text Available Studies were made an the effect of indole-3-acetic acid (IAA, gibberellic acid (GA, kinetin (Kin, and various combinations of these substances upon dry matter increments, soluble protein content, and chlorophyll levels in the cultures of Scenedesmus quadricauda (Turp. Bréb. It was found that all these phytohormones, added separately to the medium, stimulated dry matter increment and protein content, although their effect depended on the concentration and the duration of culture. Addition of various combinations of the substances under study into the medium resulted in a less pronounced increment of dry matter, whereas the content of soluble protein significantly increased. The results reflect positive reaction of Scenedesmus quadricauda to the addition of phytohormones into the medium. They also suggest some differences in the action of particular hormones.

  10. Influence of nitrogen sources on biomass productivity of microalgae Scenedesmus bijugatus.

    Science.gov (United States)

    Arumugam, Muthu; Agarwal, Ankur; Arya, Mahesh Chandra; Ahmed, Zakwan

    2013-03-01

    The influence of different nitrogen source of varying concentrations on biomass production of green algae Scenedesmus was investigated. The result revealed that there was a significant difference among nitrogen sources in promoting algal biomass growth at lower concentrations of 5 and 10 mM. Nitrate was found to be a preferred form of nitrogen source and potassium (0.32 g/L) and sodium nitrates (0.28 g/L) performed better for biomass growth of Scenedesmus. Among the ammonical forms, urea (0.25 g/L) resulted in almost equal biomass as nitrates, making it an economical substitute for nitrogen source in large scale culturing of algae being commercially available. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Studies on reduction of inorganic pollutants from wastewater by Chlorella pyrenoidosa and Scenedesmus abundans

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    B. Lekshmi

    2015-12-01

    Full Text Available The aim of this study was to identify the potential for cultivation of Chlorella pyrenoidosa and Scenedesmus abundans in raw and autoclaved domestic wastewater (sewage for nutrient removal, in a batch process. The growth was observed by measuring chlorophyll content. The inoculum size of 10% and 20% was used and the growth of microalgae and nutrient removal was monitored on daily basis. The maximum removal of ammonium nitrogen, phosphate and nitrates by Chlorella pyrenoidosa in raw samples was observed as 99%, 96% and 80%, respectively, whereas the maximum removal of ammonium nitrogen, phosphate and nitrates by Scenedesmus abundans in raw samples was observed as 98%, 95% and 83%, respectively. The maximum chlorophyll content was observed as 11.33 mg/l and 7.23 mg/l for C. pyrenoidosa and S. abundans, respectively, in raw samples. The experimental results reveal that both the microalgae are capable to grow and remove the nutrients from domestic wastewater.

  12. Hiding in plain sight: Koshicola spirodelophila gen. et sp. nov. (Chaetopeltidales, Chlorophyceae), a novel green alga associated with the aquatic angiosperm Spirodela polyrhiza.

    Science.gov (United States)

    Watanabe, Shin; Fučíková, Karolina; Lewis, Louise A; Lewis, Paul O

    2016-05-01

    Discovery and morphological characterization of a novel epiphytic aquatic green alga increases our understanding of Chaetopeltidales, a poorly known order in Chlorophyceae. Chloroplast genomic data from this taxon reveals an unusual architecture previously unknown in green algae. Using light and electron microscopy, we characterized the morphology and ultrastructure of a novel taxon of green algae. Bayesian phylogenetic analyses of nuclear and plastid genes were used to test the hypothesized membership of this taxon in order Chaetopeltidales. With next-generation sequence data, we assembled the plastid genome of this novel taxon and compared its gene content and architecture to that of related species to further investigate plastid genome traits. The morphology and ultrastructure of this alga are consistent with placement in Chaetopeltidales (Chlorophyceae), but a distinct trait combination supports recognition of this alga as a new genus and species-Koshicola spirodelophila gen. et sp. nov. Its placement in the phylogeny as a descendant of a deep division in the Chaetopeltidales is supported by analysis of molecular data sets. The chloroplast genome is among the largest reported in green algae and the genes are distributed on three large (rather than a single) chromosome, in contrast to other studied green algae. The discovery of Koshicola spirodelophila gen. et sp. nov. highlights the importance of investigating even commonplace habitats to explore new microalgal diversity. This work expands our understanding of the morphological and chloroplast genomic features of green algae, and in particular those of the poorly studied Chaetopeltidales. © 2016 Botanical Society of America.

  13. Cultivation of Microalgae Chlorella sp. and Scenedesmus sp. as a Potentional Biofuel Feedstock

    OpenAIRE

    Andrulevičiūtė, Vaida; Skorupskaitė, Virginija; Kasperovičienė, Jūratė; Makareviciene, Prof. dr. Violeta

    2011-01-01

    The growth of two robust algae strains Chlorella sp. and Scenedesmus sp. growing in Lithuanian lakes was investigated with the aim to obtain optimum conditions for biomass cultivation for biofuel production in the Lithuanian environment. Samples were taken from different nitrogen sources and of different concentrations, with addition of various concentrations of CO2 and in the presence of salt. The best biomass productivity was achieved using urea as a nitrogen source or modified growing medi...

  14. Glutamate dehydrogenase of the unicellular green alga Scenedesmus acutus : Substrate-induced conformational transition.

    Science.gov (United States)

    Shatilov, V R; Sund, H

    1983-07-01

    The coenzyme-non-specific glutamate dehydrogenase (EC 1.4.1.3) from Scenedesmus acutus in inhibited by p-hydroxymercuribenzoate only in the deamination reaction. From this result and from its stability in the presence of urea it is concluded that this enzyme exhibits and equilibrium between three conformations: aminating and deaminating conformations induced by NADH-2-oxoglutarate and NAD(+)-glutamate, respectively, and the "native" conformation in the absence of substrates.

  15. The toxic effects of lead on the freshwater green algae Chlorella and Scenedesmus

    OpenAIRE

    Dao, Ly Hai Thi

    2017-01-01

    This thesis examines the effects of lead on two freshly-isolated freshwater green algae from the genera Chlorella and Scenedesmus. Effects on growth, photosynthetic characteristics and macromolecular composition were dependent on the duration of treatment and species as well as on the pH of the environment. The thesis contributes to our understanding of the ways in which heavy metals can affect the algae that are the basis of aquatic food chains.

  16. Chemical properties and antioxidant activity of exopolysaccharides fractions from mycelial culture of Inonotus obliquus in a ground corn stover medium.

    Science.gov (United States)

    Xiang, Yuling; Xu, Xiangqun; Li, Juan

    2012-10-15

    The medicinal mushroom Inonotus obliquus has been a folk remedy for a long time in East-European and Asian countries. We first reported the enhancement in production and antioxidant activity of exopolysaccharides by I. obliquus culture under lignocellulose decomposition. In this study, the two different sources of exopolysaccharides from the control medium and the lignocellulose (corn stover) containing medium by I. obliquus in submerged fermentation were fractionated and purified by chromatography. The exopolysaccharides from the corn stover-containing medium presented significantly stronger hydroxyl and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity than the control. Three fractions from the control medium and the corn stover-containing medium were isolated respectively. The fraction of DEPL3 from the corn stover-containing medium with the highest protein content (38.3%), mannose content (49.6%), and the lowest molecular weight (29 kDa) had the highest antioxidant activity with the lowest IC50 values. In conclusion, lignocellulose decomposition changed the chemical characterisation and significantly enhanced the antioxidant activity of exopolysaccharide fractions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Insulin-sensitizing and beneficial lipid-metabolic effects of the water-soluble melanin complex extracted from Inonotus obliquus.

    Science.gov (United States)

    Lee, Jung-Han; Hyun, Chang-Kee

    2014-09-01

    Inonotus obliquus has been traditionally used for treatment of metabolic diseases; however, the mechanism remains to be elucidated. In this study, we found that the water-soluble melanin complex extracted from I. obliquus improved insulin sensitivity and reduced adiposity in high fat (HF)-fed obese mice. When the melanin complex was treated to 3T3-L1 adipocytes, insulin-stimulated glucose uptake was increased significantly, and its phosphoinositide 3-kinase-dependent action was proven with wortmannin treatment. Additionally, dose-dependent increases in Akt phosphorylation and glucose transporter 4 translocation into the plasma membrane were observed in melanin complex-treated cells. Adiponectin gene expression in 3T3-L1 cells incubated with melanin complex increased which was corroborated by increased AMP-activated protein kinase phosphorylation in HepG2 and C2C12 cells treated with conditioned media from the 3T3-L1 culture. Melanin complex-treated 3T3-L1 cells showed no significant change in expression of several lipogenic genes, whereas enhanced expressions of fatty acid oxidative genes were observed. Similarly, the epididymal adipose tissue of melanin complex-treated HF-fed mice had higher expression of fatty acid oxidative genes without significant change in lipogenic gene expression. Together, these results suggest that the water-soluble melanin complex of I. obliquus exerts antihyperglycemic and beneficial lipid-metabolic effects, making it a candidate for promising antidiabetic agent. Copyright © 2014 John Wiley & Sons, Ltd.

  18. Identification and characterization of a freshwater microalga Scenedesmus SDEC-8 for nutrient removal and biodiesel production.

    Science.gov (United States)

    Song, Mingming; Pei, Haiyan; Hu, Wenrong; Zhang, Shuo; Ma, Guixia; Han, Lin; Ji, Yan

    2014-06-01

    The selection of the right strains is of fundamental important to the success of the algae-based oil industry. From the six newly isolated microalgae strains tested for growth, fatty acid methyl ester (FAME) profiles and biodiesel properties, Scenedesmus SDEC-8, with favorable C16:0 fatty acids (73.43%), showed the best combined results. Then, morphological and molecular identification were examined. From the three wastewaters samples, Scenedesmus SDEC-8 showed good ability to yield oil and remove nutrients, which were comparable with other reports. In b artificial wastewater (TN 40 mg L(-1), TP 8 mg L(-1)), Scenedesmus SDEC-8 achieved the highest value of lipid productivity (53.84 mg L(-1) d(-1)), MUFA content (35.35%) and total FAME content (59.57±0.02 mg g(-1) DW), besides higher removal efficiencies of TN (99.18%) and TP (98.86%) helped effluent directly discharge and smaller dilution factor of N, P (3.3 and 9) which was good for lessening water utilization. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Characterization and Screening of Native Scenedesmus sp. Isolates Suitable for Biofuel Feedstock.

    Science.gov (United States)

    Gour, Rakesh Singh; Chawla, Aseem; Singh, Harvinder; Chauhan, Rajinder Singh; Kant, Anil

    2016-01-01

    In current study isolates of two native microalgae species were screened on the basis of growth kinetics and lipid accumulation potential. On the basis of data obtained on growth parameters and lipid accumulation, it is concluded that Scenedesmus dimorphus has better potential as biofuel feedstock. Two of the isolates of Scenedesmus dimorphus performed better than other isolates with respect to important growth parameters with lipid content of ~30% of dry biomass. Scenedesmus dimorphus was found to be more suitable as biodiesel feedstock candidate on the basis of cumulative occurrence of five important biodiesel fatty acids, relative occurrence of SFA (53.04%), MUFA (23.81%) and PUFA (19.69%), and more importantly that of oleic acid in its total lipids. The morphological observations using light and Scanning Electron Microscope and molecular characterization using amplified 18S rRNA gene sequences of microalgae species under study were also performed. Amplified 18S rRNA gene fragments of the microalgae species were sequenced, annotated at the NCBI website and phylogenetic analysis was done. We have published eight 18S rRNA gene sequences of microalgae species in NCBI GenBank.

  20. Salinity induced oxidative stress enhanced biofuel production potential of microalgae Scenedesmus sp. CCNM 1077.

    Science.gov (United States)

    Pancha, Imran; Chokshi, Kaumeel; Maurya, Rahulkumar; Trivedi, Khanjan; Patidar, Shailesh Kumar; Ghosh, Arup; Mishra, Sandhya

    2015-01-01

    Microalgal biomass is considered as potential feedstock for biofuel production. Enhancement of biomass, lipid and carbohydrate contents in microalgae is important for the commercialization of microalgal biofuels. In the present study, salinity stress induced physiological and biochemical changes in microalgae Scenedesmus sp. CCNM 1077 were studied. During single stage cultivation, 33.13% lipid and 35.91% carbohydrate content was found in 400 mM NaCl grown culture. During two stage cultivation, salinity stress of 400 mM for 3 days resulted in 24.77% lipid (containing 74.87% neutral lipid) along with higher biomass compared to single stage, making it an efficient strategy to enhance biofuel production potential of Scenedesmus sp. CCNM 1077. Apart from biochemical content, stress biomarkers like hydrogen peroxide, lipid peroxidation, ascorbate peroxidase, proline and mineral contents were also studied to understand the role of reactive oxygen species (ROS) mediated lipid accumulation in microalgae Scenedesmus sp. CCNM 1077. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Protein and Lipid Content of Microalgae Scenedesmus sp. Biomass Grown in Wet Market Wastewater

    Directory of Open Access Journals (Sweden)

    Apandi Najeeha Mohd

    2017-01-01

    Full Text Available Microalgae biomass is a type of organism that has various advantages and often used for variety of uses not only for wastewater treatment purposes but also serve as bio-based products development. Because of high in protein and lipid accumulation, this freshwater microalgae Scenedesmus sp. was selected for the present study. In this study, microalgae Scenedesmus sp. was grown in four concentrations of wet market wastewater (10%WM, 15%WM, 20%WM and 25%WM in comparison with the Bold Basal Medium (BBM as a control. The result shows that the highest protein content (50.72% was in 10%WM followed by 15%WM, 20%WM, 25%WM and BBM. As for lipid content, the best concentration was obtained in the 25%WM with the value of 26.7% compared to other concentrations and BBM. Therefore, the result indicates that microalgae Scenedesmus sp. biomass cultured using wet market wastewater has a great potential in producing protein-rich and lipid content which significantly could be used as a fish feed product.

  2. Evolution of rbcL group IA introns and intron open reading frames within the colonial Volvocales (Chlorophyceae).

    Science.gov (United States)

    Nozaki, Hisayoshi; Takahara, Manabu; Nakazawa, Atsushi; Kita, Yoko; Yamada, Takashi; Takano, Hiroyoshi; Kawano, Shigeyuki; Kato, Masahiro

    2002-06-01

    Mobile group I introns sometimes contain an open reading frame (ORF) possibly encoding a site-specific DNA endonuclease. However, previous phylogenetic studies have not clearly deduced the evolutionary roles of the group I intron ORFs. In this paper, we examined the phylogeny of group IA2 introns inserted in the position identical to that of the chloroplast-encoded rbcL coding region (rbcL-462 introns) and their ORFs from 13 strains of five genera (Volvox, Pleodorina, Volvulina, Astrephomene, and Gonium) of the colonial Volvocales (Chlorophyceae) and a related unicellular green alga, Vitreochlamys. The rbcL-462 introns contained an intact or degenerate ORF of various sizes except for the Gonium multicoccum rbcL-462 intron. Partial amino acid sequences of some rbcL-462 intron ORFs exhibited possible homology to the endo/excinuclease amino acid terminal domain. The distribution of the rbcL-462 introns is sporadic in the phylogenetic trees of the colonial Volvocales based on the five chloroplast exon sequences (6021 bp). Phylogenetic analyses of the conserved intron sequences resolved that the G. multicoccum rbcL-462 intron had a phylogenetic position separate from those of other colonial volvocalean rbcL-462 introns, indicating the recent horizontal transmission of the intron in the G. multicoccum lineage. However, the combined data set from conserved intron sequences and ORFs from most of the rbcL-462 introns resolved robust phylogenetic relationships of the introns that were consistent with those of the host organisms. Therefore, most of the extant rbcL-462 introns may have been vertically inherited from the common ancestor of their host organisms, whereas such introns may have been lost in other lineages during evolution of the colonial Volvocales. In addition, apparently higher synonymous substitutions than nonsynonymous substitutions in the rbcL-462 intron ORFs indicated that the ORFs might evolve under functional constraint, which could result in homing of the

  3. Efecto del nitrógeno inorgánico (NO-3 sobre el crecimiento y la composición bioquímica de la microalga Scenedesmus sp. Cepa Laun 0001

    Directory of Open Access Journals (Sweden)

    Chaparro de Valencia Martha

    2004-12-01

    Full Text Available Se evaluó el efecto de seis concentraciones de nitrógeno en forma de nitrato, sobre el crecimiento y la composición bioquímica de la microalga cepa LAUN 0001 de Scenedesmus sp. (Chlorophyceae, aislada en el laboratorio de cultivo de microalgas de la Universidad Nacional de Colombia, en un
    lote de cultivos discontinuos, aireados permanentemente. Se estableció que en la razón de 3,5:1 de N:P, se obtiene el mejor rendimiento celular (18.280.000 + 2.820.000 células/ml con una tasa de crecimiento neta alta (2,9 a los siete días. La tasa de crecimiento instantánea no presentó diferencias significativas en los valores para cada tratamiento aplicado, pero se observó una tendencia general de incremento en los tratamientos con mayor concentración. La forma colonial de cuatro células por cenobio predominó en todos los tratamientos aplicados. La concentración de lípidos y carbohidratos se incrementó significativamente en los tratamientos con baja concentración
    de nitrógeno (61-77 pg/célula, mientras que en la  concentración de proteínas y clorofila no se observaron cambios significativos. La concentración de clorofila b fue levemente mayor con respecto a la clorofila a (2,65-3,42 contra 2,33-2,8 pg/célula; la concentración de carotenos fue baja en todos los tratamientos (0,62-0,76 pg/célula aumentando  significativamente en el tratamiento donde la razón de N:P es de 14:1 (1,03 pg/célula. Los valores altos registrados en los diferentes parámetros evaluados y el fácil manejo de la cepa, hacen de esta un modelo promisorio para la realización de estudios a nivel ecológico o biotecnológico.

  4. Inhibitory effects of soluble algae products (SAP) released by Scenedesmus sp. LX1 on its growth and lipid production.

    Science.gov (United States)

    Zhang, Tian-Yuan; Yu, Yin; Wu, Yin-Hu; Hu, Hong-Ying

    2013-10-01

    Soluble algal products (SAP) accumulated in culture medium via water reuse may affect the growth of microalga during the cultivation. Scenedesmus sp. LX1, a freshwater microalga, was used in this study to investigate the effect of SAP on growth and lipid production of microalga. Under the SAP concentrations of 6.4-25.8 mg L(-1), maximum algal density (K) and maximum growth rate (Rmax) of Scenedesmus sp. LX1 were decreased by 50-80% and 35-70% compared with the control group, respectively. The effect of SAP on lipid accumulation of Scenedesmus sp. LX1 was non-significant. According to hydrophilic-hydrophobic and acid-base properties, SAP was fractionized into six fractions. All of the fractions could inhibit the growth of Scenedesmus sp. LX1. Organic bases (HIB, HOB) and hydrophilic acids (HIA) showed the strongest inhibition. HIA could also decrease the lipid content of Scenedesmus sp. LX1 by 59.2%. As the inhibitory effect, SAP should be seriously treated before water reuse. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Anti-diabetic effects of Inonotus obliquus polysaccharides in streptozotocin-induced type 2 diabetic mice and potential mechanism via PI3K-Akt signal pathway.

    Science.gov (United States)

    Wang, Jia; Wang, Cong; Li, Shuqin; Li, Weiwei; Yuan, Guoqi; Pan, Yuxiang; Chen, Haixia

    2017-11-01

    Polysaccharides are the main components of mushroom Inonotus obliquus (I. obliquus) with antihyperglycemic activities. This study was aimed to investigate the anti-diabetic effects and the potential mechanism of I. obliquus polysaccharides (IOPS) in high fat diet and STZ-induced type 2 diabetic mice. Results showed that oral administration of IOPS (900mg/kg) could significantly restore the body and fat mass weight, reduce fasting blood glucose levels, improve glucose tolerance ability, increase hepatic glycogen level and ameliorate insulin resistance compared to those of the control diabetic mice (Pdiabetic mice. The results suggested that IOPS might be a promising functional food or drug candidate for diabetes treatment. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  6. Bicarbonate supplementation enhanced biofuel production potential as well as nutritional stress mitigation in the microalgae Scenedesmus sp. CCNM 1077.

    Science.gov (United States)

    Pancha, Imran; Chokshi, Kaumeel; Ghosh, Tonmoy; Paliwal, Chetan; Maurya, Rahulkumar; Mishra, Sandhya

    2015-10-01

    The aim of the present study was to find out the optimum sodium bicarbonate concentration to produce higher biomass with higher lipid and carbohydrate contents in microalgae Scenedesmus sp. CCNM 1077. The role of bicarbonate supplementation under different nutritional starvation conditions was also evaluated. The results clearly indicate that 0.6 g/L sodium bicarbonate was optimum concentration resulting in 20.91% total lipid and 25.56% carbohydrate along with 23% increase in biomass production compared to normal growth condition. Addition of sodium bicarbonate increased the activity of nutrient assimilatory enzymes, biomass, lipid and carbohydrate contents under different nutritional starvation conditions. Nitrogen starvation with bicarbonate supplementation resulted in 54.03% carbohydrate and 34.44% total lipid content in microalgae Scenedesmus sp. CCNM 1077. These findings show application of bicarbonate grown microalgae Scenedesmus sp. CCNM 1077 as a promising feedstock for biodiesel and bioethanol production. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Inonotus obliquus polysaccharide regulates gut microbiota of chronic pancreatitis in mice.

    Science.gov (United States)

    Hu, Yang; Teng, Chunying; Yu, Sumei; Wang, Xin; Liang, Jinsong; Bai, Xin; Dong, Liying; Song, Tao; Yu, Min; Qu, Juanjuan

    2017-12-01

    Polysaccharide is efficient in attenuation of metabolic ailments and modulation of gut microbiota as prebiotics. The therapeutic effect of Inonotus obliquus polysaccharide (IOP) on chronic pancreatitis (CP) in mice has been validated in our previous study. However, it is not clear whether IOP is conducive to maintaining the homeostasis between gut microbiota and host. The aim of this study is to testify the potential effects of IOP on gut microbiota composition and diversity in mice with CP. The changes in glutathione peroxidase (GSH-P X ), total antioxidant capacity (TAOC), tumor necrosis factor alpha (TNF-α), transforming growth factor beta (TGF-β), lipase and trypsin levels were measured by commercial assay kits, meanwhile the gut microbiota composition and diversity were analyzed by high throughput sequencing. The IOP treatment increased GSH-P X and TAOC levels, and decreased TNF-α, TGF-β, lipase and trypsin levels in CP mice. It was also observed that gut microbiota in IOP treated groups were less diverse than others in terms of lower Shannon diversity index and Chao 1 estimator. IOP increased the proportion of Bacteroidetes and decreased that of Firmicutes at phylum level. Bacteroidetes was found positively correlated with GSH-P X and TAOC, and Firmicutes correlated with TNF-α, TGF-β, and lipase. In conclusion, administration of IOP could regulate gut microbiota composition and diversity to a healthy profile in mice with CP, and some bacterial phylum significantly correlated with characteristic parameters.

  8. Vastus Medialis Obliquus Muscle Morphology in Primary and Recurrent Lateral Patellar Instability

    Directory of Open Access Journals (Sweden)

    Peter Balcarek

    2014-01-01

    Full Text Available The morphology of the vastus medialis obliquus (VMO muscle in the anatomical setting of an unstable patella has not been described. Therefore, the purpose of this study was to investigate the morphological parameters of the VMO muscle that delineate its importance in the maintenance of patellofemoral joint stability. Eighty-two consecutive subjects were prospectively enrolled in this study. The groups were composed of thirty patients with an acute primary patellar dislocation, thirty patients with recurrent patellar dislocation, and twenty-two controls. Groups were adjusted according to sex, age, body mass index, and physical activity. Magnetic resonance imaging was used to measure the VMO cross-sectional area, muscle-fiber angulation, and the craniocaudal extent of the muscle in relation to the patella. No significant difference was found with respect to all measured VMO parameters between primary dislocation, recurrent dislocation, and control subjects with a trend noted for only the VMO cross-sectional area and the VMO muscle-fiber angulation. This finding is notable in that atrophy of the VMO has often been suggested to play an important role in the pathophysiology of an unstable patellofemoral joint.

  9. The Growth of Monoraphidium sp. and Scenedesmus sp. Cells in the Presence of Thorium

    Directory of Open Access Journals (Sweden)

    Juliana Cristina de Queiroz

    2012-01-01

    Full Text Available Toxicity of thorium by Monoraphidium sp. and Scenedesmus sp. was studied. Microalgal cultures were inoculated in ASM-1 medium in presence and absence of thorium. Its effect was monitored by direct counting on Fuchs-Rosenthal chamber and with software. The toxicity of thorium over the species was observed for concentrations over 50.0 mg/L. After 30 days, Monoraphidium cells decreased their concentration from 4.23×106 to 4.27×105 and 8.57×105 cells/mL, in the presence of 50.0 and 100.0 mg/L of thorium, respectively. Scenedesmus sp. cells were more resistant to thorium: for an initial cell concentration of 7.65×104 cells/mL it was observed a change to 5.25×105 and 5.12×105 cells/mL, in the presence of thorium at 50.0 and 100.0 mg/L, respectively. This is an indication that low concentrations of the radionuclide favored the growth, and that Scenedesmus cells are more resistant to thorium than Monoraphidium cells. The software used for comparison with direct count method proved to be useful for the improvement of accuracy of the results obtained, a decrease in the uncertainty and allowed recording of the data. The presence of thorium suggests that low concentrations have a positive effect on the growth, due to the presence of the nitrate, indicating its potential for ecotoxicological studies.

  10. The Growth of Monoraphidium sp. and Scenedesmus sp. Cells in the Presence of Thorium

    Science.gov (United States)

    de Queiroz, Juliana Cristina; Ferreira, Ana Cristina de Melo; da Costa, Antonio Carlos Augusto

    2012-01-01

    Toxicity of thorium by Monoraphidium sp. and Scenedesmus sp. was studied. Microalgal cultures were inoculated in ASM-1 medium in presence and absence of thorium. Its effect was monitored by direct counting on Fuchs-Rosenthal chamber and with software. The toxicity of thorium over the species was observed for concentrations over 50.0 mg/L. After 30 days, Monoraphidium cells decreased their concentration from 4.23 × 106 to 4.27 × 105 and 8.57 × 105 cells/mL, in the presence of 50.0 and 100.0 mg/L of thorium, respectively. Scenedesmus sp. cells were more resistant to thorium: for an initial cell concentration of 7.65 × 104 cells/mL it was observed a change to 5.25 × 105 and 5.12 × 105 cells/mL, in the presence of thorium at 50.0 and 100.0 mg/L, respectively. This is an indication that low concentrations of the radionuclide favored the growth, and that Scenedesmus cells are more resistant to thorium than Monoraphidium cells. The software used for comparison with direct count method proved to be useful for the improvement of accuracy of the results obtained, a decrease in the uncertainty and allowed recording of the data. The presence of thorium suggests that low concentrations have a positive effect on the growth, due to the presence of the nitrate, indicating its potential for ecotoxicological studies. PMID:22649297

  11. Maximizing biomass productivity and CO2 biofixation of microalga, Scenedesmus sp. by using sodium hydroxide.

    Science.gov (United States)

    Nayak, Manoranjan; Rath, Swagat S; Thirunavoukkarasu, Manikkannan; Panda, Prasanna K; Mishra, Barada K; Mohanty, Rama C

    2013-09-28

    A series of experiments were carried out with three native strains of microalgae to measure growth rates, biomass, and lipid productivities. Scenedesmus sp. IMMTCC-6 had better biomass growth rate and higher lipid production. The growth, lipid accumulation, and carbon dioxide (CO2) consumption rate of Scenedesmus sp. IMMTCC-6 were tested under different NaOH concentrations in modified BBM. The algal strain showed the maximum specific growth rate (0.474/day), biomass productivity (110.9 mg l(-1) d(-1)), and CO2 consumption rate (208.4 mg l(-1) d(-1)) with an NaOH concentration of 0.005 M on the 8(th) day of cultivation. These values were 2.03-, 6.89-, and 6.88-fold more than the algal cultures grown in control conditions (having no NaOH and CO2). The CO2 fixing efficiency of the microalga with other alternative carbon sources like Na2CO3 and NaHCO3 was also investigated and compared. The optimized experimental parameters at shake-flask scale were implemented for scaling up the process in a self-engineered photobioreactor. A significant increase in lipid accumulation (14.23% to 31.74%) by the algal strain from the logarithmic to stationary phases was obtained. The algal lipids were mainly composed of C16/C18 fatty acids, and are desirable for biodiesel production. The study suggests that microalga Scenedesmus sp. IMMTCC-6 is an efficient strain for biodiesel production and CO2 biofixation using stripping solution of NaOH in a cyclic process.

  12. Prevent the degradation of algicidal ability in Scenedesmus-lysing bacteria using optimized cryopreservation.

    Science.gov (United States)

    Liao, Chunli; Liu, Xiaobo

    2016-03-01

    With the anthropogenic nutrient loading increasing, the frequency and impacts of harmful algal blooms (HABs) have intensified in recent years. To biocontrol HABs, many corresponding algal-lysing bacteria have been exploited successively. However, there are few studies on an effective algal-lysing culture collection to prevent cells from death and particularly the degradation of algicidal ability to their hosts. An optimized cryopreservation was developed and experiments on the validation of this method on preventing algicidal degradation and effects of this optimized cryopreservation on the survival rate of Scenedesmus-lysing bacterium, Enterobacter NP23, isolated from Scenedesmus sp. community, China, on the algicidal dynamic of Scenedesmus wuhanensis was investigated. The optimized cryoprotectant composition consists of 30.0 g/L gelatin, 48.5 g/L sucrose, and 28.4 g/L glycerol, respectively. Using this approach, the survival rate of NP23 cells can still maintain above 90 % and the algal-lysing rate only decline 4 % after the 18-month cryoprotection. Moreover, the 16 generations' passage experiment showed a significant (p < 0.05) genetic stability of algicidal capacity after 18 months. The growth dynamic of S. wuhanensis was investigated in a 5-L bioreactor during 132 h in the absence or presence of NP23. As a result, NP23 has a significant (p < 0.05) inhibition to S. wuhanensis growth when injected into algal culture in the exponential phase at 60th hour. In addition, S. wuhanensis culture initially with NP23 exhibited a slow growth, performing a prolonged lag phase without a clear stationary phase and then rapidly decreased. Our findings, combined with the capacity of preventing the degradation of algicidal ability collectively suggest that the use of this opitimized cryopreservation may be a promising strategy for maintaining algicidal cells.

  13. A Green Algae Mixture of Scenedesmus and Schroederiella Attenuates Obesity-Linked Metabolic Syndrome in Rats

    OpenAIRE

    Senthil Arun Kumar; Marie Magnusson; Leigh C. Ward; Nicholas A. Paul; Lindsay Brown

    2015-01-01

    This study investigated the responses to a green algae mixture of Scenedesmus dimorphus and Schroederiella apiculata (SC) containing protein (46.1% of dry algae), insoluble fibre (19.6% of dry algae), minerals (3.7% of dry algae) and omega-3 fatty acids (2.8% of dry algae) as a dietary intervention in a high carbohydrate, high fat diet-induced metabolic syndrome model in four groups of male Wistar rats. Two groups were fed with a corn starch diet containing 68% carbohydrates as polysaccharide...

  14. Reaction engineering analysis of Scenedesmus ovalternus in a flat-plate gas-lift photobioreactor.

    Science.gov (United States)

    Koller, Anja Pia; Wolf, Lara; Weuster-Botz, Dirk

    2017-02-01

    Microalgal strains of the genus Scenedesmus are a promising resource for commercial biotechnological applications. The temperature-, pH- and light-dependent growth of Scenedesmus ovalternus has been investigated on a laboratory scale. Best batch process performance was obtained at 30°C, pH 8.0 and an incident photon flux density of 1300μmolphotonsm-2s-1 using a flat-plate gas-lift photobioreactor. Highest growth rate (0.11h-1) and space-time yield (1.7±0.1gCDWL-1d-1) were observed when applying these reaction conditions. Biomass concentrations of up to 7.5±0.1gCDWL-1 were achieved within six days (25.0±0.5gCDWm-2d-1). The light-dependent growth kinetics of S. ovalternus was identified using Schuster's light transfer model and Andrews' light inhibition model (KS=545μmolphotonsm-2s-1; KI=2744μmolphotonsm-2s-1; μmax=0.21h-1). The optimal mean integral photon flux density for growth of S. ovalternus was estimated to be 1223μmolphotonsm-2s-1. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Optimization of Medium Using Response Surface Methodology for Lipid Production by Scenedesmus sp.

    Directory of Open Access Journals (Sweden)

    Fangfang Yang

    2014-03-01

    Full Text Available Lipid production is an important indicator for assessing microalgal species for biodiesel production. In this work, the effects of medium composition on lipid production by Scenedesmus sp. were investigated using the response surface methodology. The results of a Plackett–Burman design experiment revealed that NaHCO3, NaH2PO4·2H2O and NaNO3 were three factors significantly influencing lipid production, which were further optimized by a Box–Behnken design. The optimal medium was found to contain 3.07 g L−1 NaHCO3, 15.49 mg L−1 NaH2PO4·2H2O and 803.21 mg L−1 NaNO3. Using the optimal conditions previously determined, the lipid production (304.02 mg·L−1 increased 54.64% more than that using the initial medium, which agreed well with the predicted value 309.50 mg L−1. Additionally, lipid analysis found that palmitic acid (C16:0 and oleic acid (C18:1 dominantly constituted the algal fatty acids (about 60% of the total fatty acids and a much higher content of neutral lipid accounted for 82.32% of total lipids, which strongly proved that Scenedesmus sp. is a very promising feedstock for biodiesel production.

  16. Sensitivity to fuel diesel oil and cell wall structure of some Scenedesmus (Chlorococcales strains

    Directory of Open Access Journals (Sweden)

    Zbigniew Tukaj

    2014-01-01

    Full Text Available Sensitivity of three Scenedesmus strains exposed to aqueous fuel-oil extract (AFOE is strongly strain-dependent S. quadricauda is the most resistant, S. armatus moderately tolerant whereas the most sensitive appears to be S. microspina. The sensitivity of tested species increases parallel with decreasing of cell size and cell number in coenobium. The values of the cell surface/cell volumes ratios only partly explain the above relationships. Electron microscope investigations reveal that the sensitivity may depend on cell wall structure of the strains. Cell wall of all here investigated strains is built of two layers: the inner so-called cellulosic layer and the outer one showing a three-laminar structure (TLS. The latter contains an acetolysis-resistant biopolymer (ARB. These two layers are similar in thickness in the three strains tested, but the surface of Scenedesmus is covered with various epistructures that are characteristic of strains. Some of them as the tightly fitting warty layer of S. armatus and especially the loosely fitting reticulate layer of S. quadricauda may contribute to lower permeability of cell wall. The structure of the rosettes also appears to be correlated with the sensitivity of strains. Presence of invaginations of plasmalemma in areas under rosettes indicates their role in transport processes inside/outside the cells.

  17. Nitrogen stress triggered biochemical and morphological changes in the microalgae Scenedesmus sp. CCNM 1077.

    Science.gov (United States)

    Pancha, Imran; Chokshi, Kaumeel; George, Basil; Ghosh, Tonmoy; Paliwal, Chetan; Maurya, Rahulkumar; Mishra, Sandhya

    2014-03-01

    The aim of present study was to investigate the effects of nitrogen limitation as well as sequential nitrogen starvation on morphological and biochemical changes in Scenedesmus sp. CCNM 1077. The results revealed that the nitrogen limitation and sequential nitrogen starvation conditions significantly decreases the photosynthetic activity as well as crude protein content in the organism, while dry cell weight and biomass productivity are largely unaffected up to nitrate concentration of about 30.87mg/L and 3 days nitrate limitation condition. Nitrate stress was found to have a significant effect on cell morphology of Scenedesmus sp. CCNM 1077. Total removal of nitrate from the growth medium resulted in highest lipid (27.93%) and carbohydrate content (45.74%), making it a potential feed stock for biodiesel and bio-ethanol production. This is a unique approach to understand morphological and biochemical changes in freshwater microalgae under nitrate limitation as well as sequential nitrate removal conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Optimization of Medium Using Response Surface Methodology for Lipid Production by Scenedesmus sp.

    Science.gov (United States)

    Yang, Fangfang; Long, Lijuan; Sun, Xiumei; Wu, Hualian; Li, Tao; Xiang, Wenzhou

    2014-01-01

    Lipid production is an important indicator for assessing microalgal species for biodiesel production. In this work, the effects of medium composition on lipid production by Scenedesmus sp. were investigated using the response surface methodology. The results of a Plackett–Burman design experiment revealed that NaHCO3, NaH2PO4·2H2O and NaNO3 were three factors significantly influencing lipid production, which were further optimized by a Box–Behnken design. The optimal medium was found to contain 3.07 g L−1 NaHCO3, 15.49 mg L−1 NaH2PO4·2H2O and 803.21 mg L−1 NaNO3. Using the optimal conditions previously determined, the lipid production (304.02 mg·L−1) increased 54.64% more than that using the initial medium, which agreed well with the predicted value 309.50 mg L−1. Additionally, lipid analysis found that palmitic acid (C16:0) and oleic acid (C18:1) dominantly constituted the algal fatty acids (about 60% of the total fatty acids) and a much higher content of neutral lipid accounted for 82.32% of total lipids, which strongly proved that Scenedesmus sp. is a very promising feedstock for biodiesel production. PMID:24663113

  19. Enhancement of lipid production in Scenedesmus sp. by UV mutagenesis and hydrogen peroxide treatment.

    Science.gov (United States)

    Sivaramakrishnan, Ramachandran; Incharoensakdi, Aran

    2017-07-01

    The high potential UV mutagenized Scenedesmus sp. was obtained in which the cells had a higher biomass and lipid content than the wild type with an increase from 1.9 to 2.4g/L and from 40 to 55% of dry cell weight respectively after 12days. Oxidative stress imposed by H2O2 treatment decreased the biomass of both the wild type and the mutant. The H2O2 treated mutant when grown in BG11 medium showed an increase in biomass which was in contrast to a decreased biomass observed in the H2O2 treated wild type. A 3-fold increase in lipid yield of 1.63g/L was obtained in the oxidative stress-induced mutant compared to the wild type. Overall results indicate that prior treatment of UV-mutagenized Scenedesmus with oxidative stress can increase the total lipid production which, due to its derived methyl ester having acceptable biodiesel properties, can be potentially utilized for biodiesel production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Development of nitrogen supply strategy for Scenedesmus rubescens attached cultivation toward growth and lipid accumulation.

    Science.gov (United States)

    Cheng, Pengfei; Wang, Yan; Osei-Wusu, David; Wang, Yuanzhu; Liu, Tianzhong

    2017-12-11

    In this study, the microalgae Scenedesmus rubescens were cultivated under the following nitrogen sources, nitrogen concentrations, and nitrogen feeding times (NFTs). This was to help assess biomass and lipid productivity. Scenedesmus rubescens can grow well by adhering to the cellulose acetate membrane in five kinds of nitrogen medium: KNO3, urea, NaNO3, (NH4)2CO3, and NH4NO3. Under the criteria of bio-productivity and lipid productivity, urea was the optimal nitrogen source. Among different urea concentrates, biomass productivity and lipid content of S. rubescens cultivated in 0.27 g/L urea medium were optimized at 8.8 g/(m2 day) and 31.1%, respectively. With attached cultivation, the highest biomass of 9.4 g/m2 was obtained at NFTs of 4 days. These results showed that culturing S. rubescens using urea as sole nitrogen source by improving nitrogen uptake with attached cultivation is more efficient.

  1. Action of some herbicides in photosynthesis of Scenedesmus as studied by their effects on oxygen evolution and cyclic photophosphorylation

    NARCIS (Netherlands)

    Rensen, van J.J.S.

    1971-01-01

    The mode of action of some herbicides, viz., DCMU, simetone, and diquat, was investigated by studying their effects upon oxygen evolution and cyclic photophosphorylation in the unicellular green alga, Scenedesmus spec.

    Oxygen evolution was measured with the aid of the WARBURG

  2. Phenotypic plasticity in the green algae Desmodesmus and Scenedesmus with special reference to the introduction of defensive morphology

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.

    2003-01-01

    Organisms belonging to the green algal genera Desmodesmus and Scenedesmus are characterized by a high degree of flexibility allowing them to be true cosmopolitans and to withstand harsh conditions. The environmental conditions determine which phenotypes are being produced and one of the most

  3. [Growth, removal of nitrogen and phosphorus, and lipid accumulation property of Scenedesmus sp. LX1 in aquaculture wastewater].

    Science.gov (United States)

    Ma, Hong-Fang; Li, Xin; Hu, Hong-Ying; Yu, Yin; Wu, Yin-Hu

    2012-06-01

    Treating wastewater by high-lipid-content microalgae, which can couple with wastewater treatment and biodiesel production, has become a new research direction in the wastewater treatment field. A high-lipid-content freshwater microalgae, Scenedesmus sp. LX1 was studied concerning its growth, removal efficiencies of nitrogen and phosphorus, and lipid accumulation property while growing in aquaculture wastewater. Results showed that the specific growth rate, maximum population density and maximum population growth rate of Scenedesmus sp. LX1 were 0.44 d(-1), 7.46 x 10(6) cells x mL(-1) and 0.82 x 10(6) cells x (mL x d)(-1), respectively. At stationary phase of training, removal efficiencies of ammonia, nitrite, nitrate and phosphorus by Scenedesmus sp. LX1 were 95.5%, 96.3%, 85.8% and 98.8%, respectively. It's biomass [dry weight] was 0.38 g x L(-1), algae lipid content was up to 31.6%. In general, Scenedesmus sp. LX1 has larger advantage in aquaculture wastewater depuration and resource utilization respect, and it can be used as the preferred algae species for coupling process.

  4. Effects of fish silage on growth and biochemical characteristics of fresh water microalga Scenedesmus sp. MB 23

    Directory of Open Access Journals (Sweden)

    Jasmin Kaippilliparambil Abdulsamad

    2017-08-01

    Full Text Available Scenedesmus sp. MB 23 was cultivated in fish silage to study the effects of different concentrations on the growth and biochemical characteristics, particularly the protein, carbohydrate and lipid properties. Fish silage with 12% concentration was most effective for the growth and biomass production of Scenedesmus sp. The microalga reached maximum cell density (2433.89 × 104 cells/mL, chlorophyll-a concentration (2.766 μg/mL, specific growth rate (0.48/d and biomass (2.73 g/L on this medium. In mass culture, enhanced production of protein (123.87 mg/g dry weight of alga, carbohydrate (44.904 mg/g dry weight of alga and lipid (84.21 mg/g dry weight of alga was found using 9% fish silage. The effective reduction (up to 90% in the concentrations of nitrate, phosphorus and ammonia in the final fish silage medium proved the removal efficiency of Scenedesmus sp. The enhanced production of Scenedesmus sp. MB 23 indicated that effective bioremediation of fish waste can be conducted using algal mass production in fish silage. The study also proved that microalgae grown in fish silage have great industrial potential and can be used as a source of feed and biofuel.

  5. Preliminary Assessment of Growth Rates on Different Concentration of Microalgae Scenedesmus sp. in Industrial Meat Food Processing Wastewater

    Directory of Open Access Journals (Sweden)

    Latiffi Nur Atikah Ahmad

    2017-01-01

    Full Text Available This study is aimed to evaluate and access the growth rates and biomass productivity in different concentrations of microalgae Scenedesmus sp. using Industrial Meat Food Processing Wastewater as a media. The focus of this study is to determine the best concentrations of microalgae Scenedesmus sp. in raw wastewater in terms of kinetics of cells growth rates. The study verified that concentration of 1×106 cells/ml of microalgae gives the highest specific growth rates of biomass at 0.4488 day-1 and 1720 cells/ml/day compare to the other concentrations, while the lowest occurred at concentration of 1×103 cells/ml at 0.4108 day-1 and 14.9 cells/ml/day. The result shows the different concentration of microalgae Scenedesmus sp. culturing in Industrial Food Processing Wastewater influence the cells growth of biomass and the optimum were obtained at concentration of 1×106 cells/ml which suggested use for Industrial Meat Food Processing Wastewater Treatment purposed. With this finding, it should be seemly to adopt and applied efficiently in treating the wastewater especially for Scenedesmus sp. type of microalgae.

  6. Efficacy of Chlorella pyrenoidosa and Scenedesmus abundans for Nutrient Removal in Rice Mill Effluent (Paddy Soaked Water).

    Science.gov (United States)

    Abinandan, S; Bhattacharya, Ribhu; Shanthakumar, S

    2015-01-01

    Microalgae are product of sustainable development owing to its ability to treat variety of wastewater effluents and thus produced biomass can serve as value added product for various commercial applications. This paper deals with the cultivation of microalgae species namely Chlorella pyrenoidosa and Scenedesmus abundans in rice mill effluent (i.e., paddy soaked water) for nutrient removal. In order to investigate the nutrient removal capability, microalgae are subjected to cultivation in both raw and autoclaved samples. The maximum phosphate removal by Scenedesmus abundans and Chlorella pyrenoidosa in raw sample was 98.3% and 97.6%, respectively, whereas, the removal of ammoniacal nitrogen by Scenedesmus abundans and Chlorella pyrenoidosa in raw sample was 92% and 90.3%, respectively. The growth (measured in terms of chlorophyll content) of Scenedesmus abundans and Chlorella pyrenoidosa in raw sample was 3.88 mg/l and 5.55 mg/l, respectively. The results indicate the suitability of microalgae cultivation in rice mill effluent treatment for nutrient removal.

  7. Investigation of a rotifer (Brachionus calyciflorus) - green alga (Scenedesmus pectinatus) interaction under non- and nutrient-limited conditions

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.

    2006-01-01

    Two-day life cycle tests with the rotifer Brachiomus calyciflorus were run to study the nutritional quality effects to rotifers of Scenedesmus pectinatus grown under non-limiting nitrogen limiting and phosphorus limiting conditions and the feedback of the rotifers oil the Food algae. Under

  8. Inhibitory and Acceleratory Effects of Inonotus obliquus on Tyrosinase Activity and Melanin Formation in B16 Melanoma Cells

    Directory of Open Access Journals (Sweden)

    Zheng-Fei Yan

    2014-01-01

    Full Text Available The aim of the present study is to preliminarily investigate the antimelanogenesis effect of Inonotus obliquus extracts by cell-free mushroom tyrosinase assay. It was found that petroleum ether and n-butanol extracts might contain unknown potential tyrosinase inhibitors, while its ethyl acetate extract might contain some unknown accelerators. Six compounds were isolated and their structures were identified by interpretation of NMR data and nicotinic acid was first discovered in Inonotus obliquus. In cells testing, betulin and trametenolic acid decreased tyrosinase activity and melanin content, while inotodiol and lanosterol significantly increased tyrosinase activity and melanin content, showing an AC⁡50 of 9.74 and 8.43 μM, respectively. Nicotinie acid, 3β,22,25-trihydroxy-lanosta-8-ene, had a little or no effect on tyrosinase. Betulin exhibited a mode of noncompetitive inhibition with a KI=KIS of 0.4 μM on tyrosinase activity showing an IC50 of 5.13 μM and being more effective than kojic acid (6.43 μM, and trametenolic acid exhibited a mode of mixed inhibition with a KI of 0.9 μM, KIS of 0.5 μM, and an IC50 of 7.25 μM. We proposed betulin and trametenolic acid as a new candidate of potent tyrosinase inhibitors and inotodiol and lanosterol as accelerators that could be used as therapeutic agent.

  9. Carotenogénesis de cinco cepas del alga Dunaliella sp. (Chlorophyceae aisladas de lagunas hipersalinas de Venezuela

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    Miguel Guevara

    2005-09-01

    . (Chlorophyceae isolated from Venezuelan hypersaline lagoons. We evaluated discontinuous cultures (Algal medium at 0.5 mM of NaNO3 , and 27% NaCl of five strains of Dunaliella sp. isolated from Venezuelan hypersaline lagoons (Araya, Coche, Peonía, Cumaraguas, and Boca Chica and one strain from a reference collection (Dunaliella salina, LB1644. Cultures were maintained to 25±1 °C, with constant aeration, photoperiod 12:12, and two light intensities (195 and 390 µE.m-2 .s-1 during 30 days. Cell count was recorded on a daily basis using a Neubaüer camera. Totals of chlorophyll a and carotenoids were measured at the end of the experiment. The largest cellular densities were measured during the smallest light intensities. The strain with the largest cellular density was isolated from Boca Chica (8 x10(6 and 2.5 x10(6 cel.ml-1 a 390 and 195µE.m-2 .s-1, respectively. The increment of light intensity produced a significant reduction of growth rates in all strains. Totals of carotenoids by volume were as large as 390 µE.m-2 .s-1. Strains LB1644, from Coche and Araya were those that produced the largest amount of carotenoids (38.4; 32.8 and 21.0 µg.ml-1 , respectively. Differences total carotenoids by cell between treatments were significant. The largest concentration was 390 µE.m-2 .s-1 . The strains LB1644 and Coche produced the highest values of carotenes (137.14 and 106.06 pg.cel-1, respectively. Differences in the relation carotenoid:chlorophyll a between the strains at various light intensities was significant. Strains LB1644 presented the largest value of the relation carotenoids:chlorophyll a (20:1 at 195 µE.m-2 .s-1. No significant differences were detected in the strain Coche (15:1. All the other strains showed relations lower than one. Our results suggest that the strains of Coche and Araya show potential to be used in the biotechnology of carotenoids production. Rev. Biol. Trop. 53(3-4: 331-337. Epub 2005 Oct 3.

  10. Thorium (IV) toxicity of green microalgae from Scenedesmus and Monoraphidium genera; Toxicidade do torio (IV) para microalgas verdes dos generos Monoraphidium e Scenedesmus

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Juliana Cristina de

    2009-07-01

    The toxicity of thorium by two green microalgae species, Monoraphidium sp. and Scenedesmus sp was studied. During the toxicity tests, the microalgae cultures were inoculated in ASM-I culture medium in the presence and absence of thorium (cultures at pH 8.0 and 6.0 in the absence of thorium, - control - and at pH 6.0 for thorium concentrations ranging from 0.5 to 100.0 mg/L Th). Its effect was monitored by direct counting on Fuchs-Rosenthal chamber and with the help of software developed by the group during the experiments. The difference in pH value in the culture medium did not affect the growth of the microalgae, and pH 6.0 was chosen as a reference in order not to compromise solubility and speciation of thorium in solution. The toxicity of the metal over the species was observed just for thorium concentrations over 50.0 mg/L. A Monoraphidium sp. culture containing 6.25x10{sup 5} microorganisms/mL reached a final concentration of 5.52x10{sup 7} microorganisms/mL in the presence of thorium in the concentration of 10.0 mg/L. If we consider the 100.0 ppm thorium solution reached a final concentration of 8.57x10{sup 6} microorganisms/mL. Control tests indicated a final concentration of 2.51x10{sup 7} microorganisms/mL at the end of the growth. Scenedesmus sp. cells proved to be more resistant to the presence of thorium in solution. Low concentrations of the radionuclide favored the growth of these microalgae. A culture containing 7.65x10{sup 5} microorganisms/mL reached a final concentration of 2.25x10{sup 6} microorganisms/mL, in the absence of thorium in the medium. Toxicological tests indicated a final culture concentration of 5.87x10{sup 6} microorganisms/mL in the presence of 0.5 mg/L thorium. The software used for comparison of direct count method proved to be very useful for the improvement of accuracy of the results obtained and a decrease in the uncertainty in counting. Beyond these advantages it also allowed recording of the data. From the present results

  11. Role of Geitlerinema sp. DE2011 and Scenedesmus sp. DE2009 as Bioindicators and Immobilizers of Chromium in a Contaminated Natural Environment.

    Science.gov (United States)

    Millach, Laia; Solé, Antoni; Esteve, Isabel

    2015-01-01

    The aim of this work was to study the potential of the two phototrophic microorganisms, both isolated from Ebro Delta microbial mats, to be used as bioindicators and immobilizers of chromium. The results obtained indicated that (i) the Minimum Metal Concentration (MMC) significantly affecting Chlorophyll a intensity in Geitlerinema sp. DE2011 and Scenedesmus sp. DE2009 was 0.25 µM and 0.75 µM, respectively, these values being lower than those established by current legislation, and (ii) Scenedesmus sp. DE2009 was able to immobilize chromium externally in extracellular polymeric substances (EPS) and intracellularly in polyphosphate (PP) inclusions. Additionally, this microorganism maintained high viability, including at 500 µM. Based on these results, we postulate that Geitlerinema sp. DE2011 and Scenedesmus sp. DE2009 are good chromium-indicators of cytotoxicity and, further, that Scenedesmus sp. DE2009 plays an important role in immobilizing this metal in a contaminated natural environment.

  12. Clorofíceas marinhas bentônicas da Praia de Serrambi, Pernambuco, Brasil Benthic marine Chlorophyceae from Serrambi Beach, Pernambuco, Brazil

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    Sônia Maria Barreto Pereira

    1998-04-01

    Full Text Available É apresentado o levantamento florístico sobre as clorofíceas marinhas bentônicas encontradas na Praia de Serrambi, litoral Sul do Estado de Pernambuco. O material estudado foi coletado em três estações, as quais foram visitadas mensalmente durante o período de abril de 1986 a setembro de 1987. As clorofíceas foram representadas na flora local por 39 espécies, três variedades e uma forma, pertencentes às ordens Ulotrichales, Ulvales, Siphonocladales, Cladophorales, Caulerpales e Dasycladales. Acetabularia calyculus Quoy & Gaimard. In Freycinet, Bryopsis pennata Lamouroux, Bryopsis plumosa (Hudson C. Agardh, Caulerpa ambigua Okamura, Caulerpa serrulata (Forsskål J. Agardh emend Børgesen, Chaetomorpha brachygona Harvey, Cladophora coelothrix Kützing, Cladophoropsis membranacea (C. Agardh Børgesen, Codium intertextum Collins & Hervey, Ernodesmis verticillata (Kützing Børgesen são novas referências para a flora do litoral de Pernambuco. Pringsheimiella scutata (Reinke von Höhnel ex Marchewianka o é também para o litoral continental do Brasil. Halimeda opuntia (L. Lamouroux foi hospedeira de maior número de epífitas, enquanto Bryopsis plumosa, quando epífita, foi a que cresceu sobre maior número de hospedeiros.This survey presents studies about benthics marine chlorophyceae found in the Serrambi Beach, South coast of Pernambuco. The material studied was collected in three stations, which were visited monthly during the period from April, 1986 to September, 1987. The chlorophyceae were represented in this flora by 39 species, three varieties and one form, from orders Ulotrichales, Ulvales, Siphonocladales, Cladophorales, Caulerpales and Dasycladales. Acetabularia calyculus Quoy & Gaimard. In Freycinet, Bryopsis pennata Lamouroux, Bryopsis plumosa (Hudson C. Agardh, Caulerpa ambigua Okamura, Caulerpa serrulata (Forsskål J. Agardh emend Børgesen, Chaetomorpha brachygona Harvey, Cladophora coelothrix Kützing, Cladophoropsis

  13. Bioaccumulation and toxicity of selenium compounds in the green alga Scenedesmus quadricauda

    Science.gov (United States)

    Umysová, Dáša; Vítová, Milada; Doušková, Irena; Bišová, Kateřina; Hlavová, Monika; Čížková, Mária; Machát, Jiří; Doucha, Jiří; Zachleder, Vilém

    2009-01-01

    Background Selenium is a trace element performing important biological functions in many organisms including humans. It usually affects organisms in a strictly dosage-dependent manner being essential at low and toxic at higher concentrations. The impact of selenium on mammalian and land plant cells has been quite extensively studied. Information about algal cells is rare despite of the fact that they could produce selenium enriched biomass for biotechnology purposes. Results We studied the impact of selenium compounds on the green chlorococcal alga Scenedesmus quadricauda. Both the dose and chemical forms of Se were critical factors in the cellular response. Se toxicity increased in cultures grown under sulfur deficient conditions. We selected three strains of Scenedesmus quadricauda specifically resistant to high concentrations of inorganic selenium added as selenite (Na2SeO3) – strain SeIV, selenate (Na2SeO4) – strain SeVI or both – strain SeIV+VI. The total amount of Se and selenomethionine in biomass increased with increasing concentration of Se in the culturing media. The selenomethionine made up 30–40% of the total Se in biomass. In both the wild type and Se-resistant strains, the activity of thioredoxin reductase, increased rapidly in the presence of the form of selenium for which the given algal strain was not resistant. Conclusion The selenium effect on the green alga Scenedesmus quadricauda was not only dose dependent, but the chemical form of the element was also crucial. With sulfur deficiency, the selenium toxicity increases, indicating interference of Se with sulfur metabolism. The amount of selenium and SeMet in algal biomass was dependent on both the type of compound and its dose. The activity of thioredoxin reductase was affected by selenium treatment in dose-dependent and toxic-dependent manner. The findings implied that the increase in TR activity in algal cells was a stress response to selenium cytotoxicity. Our study provides a new

  14. Bioaccumulation and toxicity of selenium compounds in the green alga Scenedesmus quadricauda

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    Doucha Jiří

    2009-05-01

    Full Text Available Abstract Background Selenium is a trace element performing important biological functions in many organisms including humans. It usually affects organisms in a strictly dosage-dependent manner being essential at low and toxic at higher concentrations. The impact of selenium on mammalian and land plant cells has been quite extensively studied. Information about algal cells is rare despite of the fact that they could produce selenium enriched biomass for biotechnology purposes. Results We studied the impact of selenium compounds on the green chlorococcal alga Scenedesmus quadricauda. Both the dose and chemical forms of Se were critical factors in the cellular response. Se toxicity increased in cultures grown under sulfur deficient conditions. We selected three strains of Scenedesmus quadricauda specifically resistant to high concentrations of inorganic selenium added as selenite (Na2SeO3 – strain SeIV, selenate (Na2SeO4 – strain SeVI or both – strain SeIV+VI. The total amount of Se and selenomethionine in biomass increased with increasing concentration of Se in the culturing media. The selenomethionine made up 30–40% of the total Se in biomass. In both the wild type and Se-resistant strains, the activity of thioredoxin reductase, increased rapidly in the presence of the form of selenium for which the given algal strain was not resistant. Conclusion The selenium effect on the green alga Scenedesmus quadricauda was not only dose dependent, but the chemical form of the element was also crucial. With sulfur deficiency, the selenium toxicity increases, indicating interference of Se with sulfur metabolism. The amount of selenium and SeMet in algal biomass was dependent on both the type of compound and its dose. The activity of thioredoxin reductase was affected by selenium treatment in dose-dependent and toxic-dependent manner. The findings implied that the increase in TR activity in algal cells was a stress response to selenium cytotoxicity

  15. Renal Protective Effects of Low Molecular Weight of Inonotus obliquus Polysaccharide (LIOP on HFD/STZ-Induced Nephropathy in Mice

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    Yen-Jung Chou

    2016-09-01

    Full Text Available Diabetic nephropathy (DN is the leading cause of end-stage renal disease in diabetes mellitus. Oxidative stress, insulin resistance and pro-inflammatory cytokines have been shown to play an important role in pathogeneses of renal damage on type 2 diabetes mellitus (DM. Inonotus obliquus (IO is a white rot fungus that belongs to the family Hymenochaetaceae; it has been used as an edible mushroom and exhibits many biological activities including anti-tumor, anti-oxidant, anti-inflammatory and anti-hyperglycemic properties. Especially the water-soluble Inonotus obliquus polysaccharides (IOPs have been previously reported to significantly inhibit LPS-induced inflammatory cytokines in mice and protect from streptozotocin (STZ-induced diabetic rats. In order to identify the nephroprotective effects of low molecular weight of IOP fraction (LIOP, from the fruiting bodies of Inonotus obliquus, high-fat diet (HFD plus STZ-induced type 2-like diabetic nephropathy C57BL/6 mice were investigated in this study. Our data showed that eight weeks of administration of 10–100 kDa, LIOP (300 mg/kg had progressively increased their sensitivity to glucose (less insulin tolerance, reduced triglyceride levels, elevated the HDL/LDL ratio and decreased urinary albumin/creatinine ratio(ACR compared to the control group. By pathological and immunohistochemical examinations, it was indicated that LIOP can restore the integrity of the glomerular capsules and increase the numbers of glomerular mesangial cells, associated with decreased expression of TGF-β on renal cortex in mice. Consistently, three days of LIOP (100 μg/mL incubation also provided protection against STZ + AGEs-induced glucotoxicity in renal tubular cells (LLC-PK1, while the levels of NF-κB and TGF-β expression significantly decreased in a dose-dependent manner. Our findings demonstrate that LIOP treatment could ameliorate glucolipotoxicity-induced renal fibrosis, possibly partly via the inhibition of NF

  16. Development of genetic transformation methodologies for an industrially-promising microalga: Scenedesmus almeriensis.

    Science.gov (United States)

    Dautor, Yasmeen; Úbeda-Mínguez, Patricia; Chileh, Tarik; García-Maroto, Federico; Alonso, Diego López

    2014-12-01

    The development of the microalgal industry requires advances in every aspect of microalgal biotechnology. In this regard, the availability of genetic engineering tools for industrially-promising species is key. As Scenedesmus almeriensis has promise for industrial use, we describe here an Agrobacterium-based methodology that allows stable genetic transformation of it for the first time, thus opening the way to its genetic manipulation. Transformation was accomplished using two different antibiotic resistance genes [hygromicine phophotransferase (hpt) and Shble] and it is credited by PCR amplification of both hpt/Shble and GUS genes and by the β-glucuronidase activity of transformed cells. Nevertheless, the single 35S promoter seems unable to direct gene expression to a convenient level in S. almeriensis as suggested by the low GUS enzymatic activity. Temperature was critical for the transformation efficiency.

  17. Effects of pulsed electric field treatment on enhancing lipid recovery from the microalga, Scenedesmus.

    Science.gov (United States)

    Lai, YenJung Sean; Parameswaran, Prathap; Li, Ang; Baez, Maria; Rittmann, Bruce E

    2014-12-01

    Chloroform and methanol are superior solvents for lipid extraction from photosynthetic microorganisms, because they can overcome the resistance offered by the cell walls and membranes, but they are too toxic and expensive to use for large-scale fuel production. Biomass from the photosynthetic microalga Scenedesmus, subjected to a commercially available pre-treatment technology called Focused-Pulsed® (FP), yielded 3.1-fold more crude lipid and fatty acid methyl ester (FAME) after extraction with a range of solvents. FP treatment increased the FAME-to-crude-lipid ratio for all solvents, which means that the extraction of non-lipid materials was minimized, while the FAME profile itself was unchanged compared to the control. FP treatment also made it possible to use only a small proportion of chloroform and methanol, along with isopropanol, to obtain equivalent yields of lipid and FAME as with 100% chloroform plus methanol. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Chronic effects of the ionic liquid [C4mim][Cl] towards the microalga Scenedesmus quadricauda.

    Science.gov (United States)

    Deng, Yun; Beadham, Ian; Wu, Jie; Chen, Xiao-Di; Hu, Lan; Gu, Jun

    2015-09-01

    Chronic effects of the ionic liquid [C4mim][Cl] (mp 73 °C) towards the microalga, Scenedesmus quadricauda were studied by flow cytometry, monitoring multiple endpoints of cell density, esterase activity, membrane integrity, reactive oxygen species and chlorophyll fluorescence. Toxicity was clearly in evidence, and although increased esterase activity indicated hormesis during initial exposure to [C4mim][Cl], inhibition of both esterase activity and chlorophyll fluorescence became apparent after 3 days. Cell density was also decreased by culturing with [C4mim][Cl], but this effect was clearly concentration-dependent and only became significant during the second half of the experiment. In contrast, [C4mim][Cl] had only a modest effect on reactive oxygen species (ROS) and caused little damage to cell membranes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Effect of nitrogen source on growth and lipid accumulation in Scenedesmus abundans and Chlorella ellipsoidea.

    Science.gov (United States)

    González-Garcinuño, Álvaro; Tabernero, Antonio; Sánchez-Álvarez, José Ma; Martin Del Valle, Eva M; Galán, Miguel A

    2014-12-01

    Discovering microalgae strains containing a high lipid yield and adequate fatty acid composition is becoming a crucial fact in algae-oil factories. In this study, two unknown strains, named Scenedesmus abundans and Chlorella ellipsoidea, have been tested for their response to different nitrogen sources, in order to determine its influence in the production of lipids. For S. abundans, autotrophic culture with ammonium nitrate offers the maximum lipid yield, obtaining up to 3.55 mg L(-1) d(-1). For C. ellipsoidea, heterotrophic culture with ammonium nitrate has been shown to be the best condition, reaching a lipid production of 9.27 mg L(-1) d(-1). Moreover, fatty acid composition obtained from these cultures meets international biodiesel standards with an important amount of C18:1, achieving 70% of total fatty acids and thus representing a potential use of these two strains at an industrial scale. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. The mechanism of lipids extraction from wet microalgae Scenedesmus sp. by ionic liquid assisted subcritical water

    Science.gov (United States)

    Yu, Zhuanni; Chen, Xiaolin; Xia, Shuwei

    2016-06-01

    In this paper, the total sugar concentration, protein concentration, lipid yield and morphology characteristics of the algae residue were determined to explain the mechanism of lipids extraction from wet microalgae Scenedesmus sp. by ionic liquid assisted subcritical water. The results showed similar variation for the sugar, protein and lipid. However, the total sugar was more similar to lipids yield, so the results showed that the reaction between ionic liquid and cellulose and hemicellulose in cell wall was the most important step which determined the lipids extration directly. And the total sugar variation may be representing the lipids yield. For later lipids extraction, we can determine the total sugar concentration to predict the extraction end product.

  1. Biodiesel production from Scenedesmus bijuga grown in anaerobically digested food wastewater effluent.

    Science.gov (United States)

    Shin, Dong Yun; Cho, Hyun Uk; Utomo, Joseph Christian; Choi, Yun-Nam; Xu, Xu; Park, Jong Moon

    2015-05-01

    Microalgae, Scenedesmus bijuga, was cultivated in anaerobically digested food wastewater effluent (FWE) to treat the wastewater and produce biodiesel simultaneously. Three different mixing ratios with municipal wastewater were compared for finding out proper dilution ratio in biodiesel production. Of these, 1/20 diluted FWE showed the highest biomass production (1.49 g/L). Lipid content was highest in 1/10 diluted FWE (35.06%), and the lipid productivity showed maximum value in 1/20 diluted FWE (15.59 mg/L/d). Nutrient removal was also measured in the cultivation. FAME compositions were mainly composed of C16-C18 (Over 98.94%) in S. bijuga. In addition, quality of FAMEs was evaluated by Cetane Number (CN) and Bis-allylic Position Equivalent (BAPE). Copyright © 2015. Published by Elsevier Ltd.

  2. Synergistic Effect of Hormones and Biosolids on Scenedesmus abundans for Eliciting Total Biolipids.

    Science.gov (United States)

    Chellamboli, Chelladurai; Perumalsamy, Muthiah

    2016-12-01

      This study states an integrated approach to grow Scenedesmus abundans in the presence of biostimulants as a robust flourishing organism pertaining to attain the maximum yield of the biodiesel through transesterification. These assessments are especially targeted to achieve the appreciable profit on biodiesel using three biostimulants such as, Indole 3-acetic acid (3 IAA), 6-Benzylaminopurine (6 BAP), and Gibberellic acid (GA) hormones. The proposed schema proved a rise in biomass; as well as lipid content, compared with an alga grown in the absence of hormones. The harvested S. abundans was exposed to many physio-chemical analyses for characterization of formulating microalgae cells. S. abundans cultivated in the 6-BAP hormone exhibit 2.17, 0.95, 1.745, and 15.6 fold increase in biomass, protein, carbohydrate and lipid content. Therefore, S. abundans was emphatically an apt species for the production of biodiesel.

  3. The influence of gibberellic acid and kinetin on the growth of Scenedesmus quadricauda (Turp. Breb.

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    J. Buczek

    2015-01-01

    Full Text Available The influence of gibberellic acid (GA3 and of kinetin (6-furfurylamino purine on the increment of cell number increase in dry weight and upon protein level in Scenedesmus quadricauda (Turp. Bréb. was studied. It was found that 10-7 M GA3 stimulates at the same time cell growth and dry weight increase of the algae. No influence of GA3 upon the protein content was observed. Kinetin of 10- M concentration stimulates in the initial growth phase cell multiplication and increases the protein level. This substance promotes the increment in dry weight however in the later phase of growth. Furthermore kinetin prolongs the viability of algae, extending the growth phase.

  4. Biodegradation of naproxen by freshwater algae Cymbella sp. and Scenedesmus quadricauda and the comparative toxicity.

    Science.gov (United States)

    Ding, Tengda; Lin, Kunde; Yang, Bo; Yang, Mengting; Li, Juying; Li, Wenying; Gan, Jay

    2017-08-01

    Naproxen is one of the most prevalent pharmaceuticals and of great environment concern. Information about bioremediation of naproxen by algae remains limited and no study has been reported on the degradation mechanism and the toxicity of NPX on algae. In this study, both Cymbella sp. and Scenedesmus quadricauda showed complete growth inhibition (100%) at 100mgL-1 within 24h. Biochemical characteristics including chlorophyll a, carotenoid contents and enzyme activities for these two microalgae were affected by NPX at relatively high concentrations after 4d of exposure. Degradation of naproxen was accelerated by both algae species. Cymbella sp. showed a more satisfactive effect in the bioremediation of NPX with higher removal efficiency. A total of 12 metabolites were identified by LC-MS/MS and the degradation pathways of naproxen in two algae were proposed. Hydroxylation, decarboxylation, demethylation, tyrosine conjunction and glucuronidation contributed to naproxen transformation in algal cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. The Effects of Different Light Qualities on Gamma Ray-Treated Scenedesmus

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    Adoracion Arañez

    1992-06-01

    Full Text Available Unialgal culture of Scenedesmus quadricauda (Turp. Breb. suspended in distilled water was treated with 0 Gy (control, 40 Gy, 80 Gy, and 120 Gy gamma rays from a to 60Co source at Philippine Nuclear Research Institute, placed in one-liter flasks, enough Bold basal medium added to give a transmittance of 97% determined by using a spectrophotometer, kept in the dark for 24 hrs., then placed in vials and distributed equally in three growth chambers with white light, red light, and blue light. The lighting was continuous with algae subjected to the same light intensity, and the temperature maintained at 30±1° C. A sterile regimen was followed.For the first two weeks, the growth rates of algae under white light were highest, followed by those under red light, while those grown under blue light had the lowest growth rate. After the second week, differences in growth rates were not significant anymore. During the first week, generally low doses of gamma radiation had stimulating effects on growth rates while high doses had inhibitory effects on growth. The abnormal Scenedesmus observed were enlarged cells of normal shape in coenobia of two cells and four cells, enlarged cells that were not forming coenobia, coenobia composed of enlarged cells of abnormal shape, coenobia composed of enlarged cells of different sizes, cells with kidney-shape chloroplast, coenobia with cells that were not in alignment as in the normal ones, and cells that were colorless. Percentage of coenobia with enlarged cells determined one week after the treatment showed that higher doses generally produced more enlarged cells than lower doses. Treated algae grown in red light and blue light which showed lesser growth rates than those under white light had higher percentage of enlarged cells. Enlarged cells of normal shape were successfully propagated for more than ten generations.

  6. DESCRIPTION OF TWO NEW MONOECIOUS SPECIES OF VOLVOX SECT. VOLVOX (VOLVOCACEAE, CHLOROPHYCEAE), BASED ON COMPARATIVE MORPHOLOGY AND MOLECULAR PHYLOGENY OF CULTURED MATERIAL(1).

    Science.gov (United States)

    Isaka, Nanako; Kawai-Toyooka, Hiroko; Matsuzaki, Ryo; Nakada, Takashi; Nozaki, Hisayoshi

    2012-06-01

    Species of Volvox sect. Volvox (Volvocaceae, Chlorophyceae) are unique because they have thick cytoplasmic bridges between somatic cells and spiny-walled zygotes. This section is taxonomically important because the genus Volvox is polyphyletic. However, taxonomic studies of species in Volvox sect. Volvox have not been carried out on cultured material. Here, we performed a taxonomic study of monoecious species of Volvox sect. Volvox based on the comparative morphology and molecular phylogeny of chloroplast genes and the internal transcribed spacer (ITS) regions of nuclear rDNA using various strains originating from Japan and two preserved strains from the USA. The strains were clearly divided into four species, V. globator L., V. barberi W. Shaw, V. kirkiorum sp. nov., and V. ferrisii sp. nov., on the basis of differences in numbers of zygotes (eggs) in the sexual spheroids, form of zygote wall, and somatic cell shape. Sequences for ITS of nuclear rDNA resolved that the two new species have phylogenetic positions separated from V. globator, V. barberi, V. capensis F. Rich et Pocock, and V. rousseletii G. S. West UTEX 1862 within Volvox sect. Volvox. © 2012 Phycological Society of America.

  7. Cultivation of Monoraphidium sp., Chlorella sp. and Scenedesmus sp. algae in Batch culture using Nile tilapia effluent.

    Science.gov (United States)

    Guerrero-Cabrera, Luis; Rueda, José A; García-Lozano, Hiram; Navarro, A Karin

    2014-06-01

    Monoraphidium sp., Chlorella sp. and Scenedesmus sp. algae were cultured in three volumes of Tilapia Effluent Medium (TEM) in comparison with the Bold Basal Medium (BBM) (Nichols and Bold, 1965). Specific growth rate (μ'), biomass dry productivity (Q), volumetric productivity (Qv) as well as lipid and protein content were measured. Then, volumetric productivities for both lipids and proteins were calculated (QVL and QVP). In Scenedesmus sp., BBM produced higher μ' and Qv than TEM in 1.5L volume. Chlorella sp. showed a higher QVL for BBM than TEM. Any observed difference in protein or lipid productivities among volumes was in favor of a greater productivity for 1.5L volume. Even when TEM had a larger protein content in Chlorella sp. than BBM, QVP was not different. Current results imply that TEM can be used as an alternative growth medium for algae when using Batch cultures, yet productivity is reduced. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Maximizing the productivity of the microalgae Scenedesmus AMDD cultivated in a continuous photobioreactor using an online flow rate control.

    Science.gov (United States)

    McGinn, Patrick J; MacQuarrie, Scott P; Choi, Jerome; Tartakovsky, Boris

    2017-01-01

    In this study, production of the microalga Scenedesmus AMDD in a 300 L continuous flow photobioreactor was maximized using an online flow (dilution rate) control algorithm. To enable online control, biomass concentration was estimated in real time by measuring chlorophyll-related culture fluorescence. A simple microalgae growth model was developed and used to solve the optimization problem aimed at maximizing the photobioreactor productivity. When optimally controlled, Scenedesmus AMDD culture demonstrated an average volumetric biomass productivity of 0.11 g L-1 d-1 over a 25 day cultivation period, equivalent to a 70 % performance improvement compared to the same photobioreactor operated as a turbidostat. The proposed approach for optimizing photobioreactor flow can be adapted to a broad range of microalgae cultivation systems.

  9. Differential effects of P25 TiO2 nanoparticles on freshwater green microalgae: Chlorella and Scenedesmus species.

    Science.gov (United States)

    Roy, Rajdeep; Parashar, Abhinav; Bhuvaneshwari, M; Chandrasekaran, N; Mukherjee, Amitava

    2016-07-01

    P25 TiO2 nanoparticles majorly used in cosmetic products have well known detrimental effects towards the aquatic environment. In a freshwater ecosystem, Chlorella and Scenedesmus are among the most commonly found algal species frequently used to study the effects of metal oxide nanoparticles. A comparative study has been conducted herein to investigate differences in the toxic effects caused by these nanoparticles towards the two algae species. The three different concentrations of P25 TiO2 NPs (0.01, 0.1 & 1μg/mL, i.e., 0.12, 1.25 and 12.52μM) were selected to correlate surface water concentrations of the nanoparticles, and filtered and sterilized fresh water medium was used throughout this study. There was significant increase (pScenedesmus under only visible light (pScenedesmus species, which could easily be correlated with the uptake of the NPs. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Studies on toxicity of aluminum oxide (Al2O3) nanoparticles to microalgae species: Scenedesmus sp. and Chlorella sp.

    Science.gov (United States)

    Sadiq, I. Mohammed; Pakrashi, Sunandan; Chandrasekaran, N.; Mukherjee, Amitava

    2011-08-01

    In view of increasing commercial applications of metal oxide nanoparticles their toxicity assessment becomes important. Alumina (Al2O3) nanoparticles have wide range of applications in industrial as well as personal care products. In the absence of prior report on toxicological impact of alumina nanoparticles to microalgae, the principal objective of this study was to demonstrate the effect of the nanoparticles on microalgae isolated from aquatic environment ( Scenedesmus sp. and Chlorella sp.). The growth inhibitory effect of alumina nanoparticles was observed for both the species (72 h EC50 value, 45.4 mg/L for Chlorella sp.; 39.35 mg/L for Scenedesmus sp.). Bulk alumina also showed toxicity though to a lesser extent (72 h EC50 value, 110.2 mg/L for Chlorella sp.; 100.4 mg/L for Scenedesmus sp.). A clear decrease in chlorophyll content was observed in the treated cells compared to the untreated ones, more effect being notable in the case of nanoparticles. Preliminary results based on FT-IR studies, optical and scanning electron microscopic images suggest interaction of the nanoparticles with the cell surface.

  11. Scenedesmus-based treatment of nitrogen and phosphorus from effluent of anaerobic digester and bio-oil production.

    Science.gov (United States)

    Kim, Ga-Yeong; Yun, Yeo-Myeong; Shin, Hang-Sik; Kim, Hee-Sik; Han, Jong-In

    2015-11-01

    In this study, a microalgae-based technology was employed to treat wastewater and produce biodiesel at the same time. A local isolate Scenedesmus sp. was found to be a well suited species, particularly for an effluent from anaerobic digester (AD) containing low carbon but high nutrients (NH3-N=273mgL(-1), total P=58.75mgL(-1)). This algae-based treatment was quite effective: nutrient removal efficiencies were over 99.19% for nitrogen and 98.01% for phosphorus. Regarding the biodiesel production, FAME contents of Scenedesmus sp. were found to be relatively low (8.74% (w/w)), but overall FAME productivity was comparatively high (0.03gL(-1)d(-1)) due to its high biomass productivity (0.37gL(-1)d(-1)). FAMEs were satisfactory to the several standards for the biodiesel quality. The Scenedesmus-based technology may serve as a promising option for the treatment of nutrient-rich wastewater and especially so for the AD effluent. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Effect of Light Intensity for Optimum Biomass and Lipid Production from Scenedesmus dimorphus (Turpin) Kützing

    Science.gov (United States)

    Kurniawati, F. N.; Mahajoeno, E.; Sunarto; Sari, S. L. A.

    2017-07-01

    One source of alternative energy substitute for petroleum raw materials is renewable vegetable oils known as biodiesel. Biodiesel can be produced from microalgae, since it was more efficient and environmentally friendly. Scenedesmus dimorphus (Turpin) Kützing was developed as a source of biodiesel since it had potential of high lipid production. The aims of this research were to know the rate of growth of Scenedesmus dimorphus in different lighting and the optimimum light intensity for biomass and lipid production. This research used a completely randomized design consisting of 3 treatments with 3 replications. Treatments in this research were the light intensity, i.e. 7,500, 10,000, and 12,500 lux. Scenedesmus dimorphus was grew in Bold’s Basal Medium (BBM). Parameters observed in this research were the cell number, biomass and lipid production of S. dimorphus. Data were analyzed by ANOVA followed by DMRT 5%. The results showed that the optimum growth rate of S. dimorphus was in the intensity of 12,500 lux that was 100.80 x 106 cells.ml-1. The optimum production of biomass and lipids was in treatment 12,500 lux i.e; 1.1407 g.L-1 and 0.2520 g.L-1 (22.28% dry weight).

  13. [Effect of inorganic carbon supplement on the growth and lipid accumulation properties of Scenedesmus sp. LX1].

    Science.gov (United States)

    Li, Xin; Hu, Hong-Ying; Zhang, Yu-Ping

    2011-08-01

    With secondary effluent as growth medium, the growth and lipid accumulation properties of Scenedesmus sp. LX1 in the control and carbon supplement (Na2CO3, NaHCO3 and CO2) groups were compared. After 14 days of cultivation, there was no significant difference in growth and lipid accumulation of Scenedesmus sp. LX1 among the 4 groups. The algal biomass, lipid and triacylglycerols production were 0.70-0.77 g x L(-1), 0.27-0.34 g x L(-1) and 0.029-0.033 g x L(-1), respectively, and the lipid content per algal biomass was 35% - 45%. The microalgal photosynthesis would increase the water's pH to about 9.2, which could induce CO2 transferring into secondary effluent. In control group, the amount of CO2 transferring from atmosphere into secondary effluent was 1.0 g x L(-1), occupying 97% of total fixed CO2 by microalga. Calculation shows that, the CO2 transferring from atmosphere into secondary effluent is enough to support microalgal growth and lipid accumulation. Therefore, to cultivate Scenedesmus sp. LX1 in secondary effluent, there is no need of carbon supplement.

  14. In vitro antitumor activity and structure characterization of ethanol extracts from wild and cultivated Chaga medicinal mushroom, Inonotus obliquus (Pers.:Fr.) Pilát (Aphyllophoromycetideae).

    Science.gov (United States)

    Sun, Yong; Yin, Ting; Chen, Xian-Hui; Zhang, Gong; Curtis, Rempel B; Lu, Zhan-Hui; Jiang, Ji-Hong

    2011-01-01

    Inonotus obliquus (Pers.:Fr.) Pilát has been traditionally used as a folk remedy for treatment of cancers, cardiovascular disease and diabetes in Russia, Poland, and most of the Baltic countries, but natural reserves of this fungus have nearly been exhausted. This study was designed to investigate the artificial cultivation of I. obliquus and the antitumor activity of its tissues. The ethanol extract of cultivated sclerotium had the highest cell growth inhibitory rate (74.6%) as determined by an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. 78% of the bags produced sclerotia and only 6.17 g/bag of sclerotium was obtained. Extracts of the cultivated fruiting body showed 44.2% inhibitory activity against tumor cells. However, the yield was as high as 18.24 g/bag, and 98% of the bags produced fruiting body. The results of gas chromatography-mass spectroscopy (GC-MS) showed that similar compounds were extracted from the wild and cultivated samples. The principal compounds observed were lanosterol, inotodiol, and ergosterol. Their percentages of the mass fraction were 86.1, 59.9, and 71.8% of the total, for the wild sclerotium, cultivated sclerotium, and cultivated fruiting body, respectively. Ergosterol was found to be much higher (27.32%) in cultivated fruiting body. We conclude that cultivated fruiting body of I. obliquus obtained by inoculation of the substrate with spawn mycelium of the fifth generation could serve as an ideal substitute for the wild I. obliquus.

  15. Beneficial effects of the ethanol extract from the dry matter of a culture broth of Inonotus obliquus in submerged culture on the antioxidant defence system and regeneration of pancreatic beta-cells in experimental diabetes in mice.

    Science.gov (United States)

    Xu, Hong-Yu; Sun, Jun-En; Lu, Zhen-Ming; Zhang, Xiao-Mei; Dou, Wen-Fang; Xu, Zheng-Hong

    2010-04-01

    The antihyperglycaemic and antilipidperoxidative effects of the ethanol extract from the dry matter of a culture broth (DMCB) of Inonotus obliquus were investigated in alloxan-induced diabetic mice and the possible mechanism of action was also discussed. In alloxan-induced diabetic mice, treatment with the ethanol extract from DMCB of I. obliquus (30 and 60 mg kg(-1) body weight (b.w.) for 21 days) showed a significant decrease in blood glucose level: the percentage reductions on the 7th day were 11.54 and 11.15%, respectively. However, feeding of this drug for three weeks produced reduction of 22.51 and 24.32%. Furthermore, the ethanol extract from the DMCB of I. obliquus treatment significantly decreased serum contents of free fatty acids, total cholesterol, triglycerides and low-density lipoprotein-cholesterol, whereas it effectively increased high-density lipoprotein-cholesterol, insulin levels and hepatic glycogen contents in livers of diabetic mice. Besides this, the ethanol extracts from the DMCB treatment significantly increased catalase, superoxide dismutase and glutathione peroxidase activities, except for decreasing the maleic dialdehyde level in diabetic mice. Histological morphology examination showed that the ethanol extract from the DMCB of I. obliquus restored the damage of pancreatic tissues in mice with diabetes mellitus. The results showed that the ethanol extract from the DMCB of I. obliquus possesses significant antihyperglycaemic, antilipidperoxidative and antioxidant effects in alloxan-induced diabetic mice.

  16. Age affects not only metabolome but also metal toxicity in Scenedesmus quadricauda cultures.

    Science.gov (United States)

    Kováčik, Jozef; Klejdus, Bořivoj; Babula, Petr; Hedbavny, Josef

    2016-04-05

    Responses of Scenedesmus quadricauda grown in vitro and differing in age (old culture-13 months, young culture-1 month) to short-term cadmium (Cd) or nickel (Ni) excess (24h) were compared. Higher age of the culture led to lower amount of chlorophylls, ascorbic acid and glutathione but higher signal of ROS. Surprisingly, sucrose was detected using DART-Orbitrap MS in both old and young culture and subsequent quantification confirmed its higher amount (ca. 3-times) in the old culture. Cd affected viability and ROS amount more negatively than Ni that could arise from excessive Cd uptake which was also higher in all treatments than in respective Ni counterparts. Surprisingly, nitric oxide was not extensively different in response to age or metals. Strong induction of phytochelatin 2 is certainly Cd-specific response while Ni also elevated ascorbate content. Krebs cycle acids were more accumulated in the young culture but they were rather elevated in the old culture (citric acid under Ni excess). We conclude that organic solid 'Milieu Bristol' medium we tested is suitable for long-term storage of unicellular green algae (also successfully tested for Coccomyxa sp. and Parachlorella sp.) and the impact of age on metal uptake may be useful for bioremediation purposes. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Enhancement of Lipid Extraction from Marine Microalga, Scenedesmus Associated with High-Pressure Homogenization Process

    Directory of Open Access Journals (Sweden)

    Seok-Cheol Cho

    2012-01-01

    Full Text Available Marine microalga, Scenedesmus sp., which is known to be suitable for biodiesel production because of its high lipid content, was subjected to the conventional Folch method of lipid extraction combined with high-pressure homogenization pretreatment process at 1200 psi and 35°C. Algal lipid yield was about 24.9% through this process, whereas only 19.8% lipid can be obtained by following a conventional lipid extraction procedure using the solvent, chloroform : methanol (2 : 1, v/v. Present approach requires 30 min process time and a moderate working temperature of 35°C as compared to the conventional extraction method which usually requires >5 hrs and 65°C temperature. It was found that this combined extraction process followed second-order reaction kinetics, which means most of the cellular lipids were extracted during initial periods of extraction, mostly within 30 min. In contrast, during the conventional extraction process, the cellular lipids were slowly and continuously extracted for >5 hrs by following first-order kinetics. Confocal and scanning electron microscopy revealed altered texture of algal biomass pretreated with high-pressure homogenization. These results clearly demonstrate that the Folch method coupled with high-pressure homogenization pretreatment can easily destruct the rigid cell walls of microalgae and release the intact lipids, with minimized extraction time and temperature, both of which are essential for maintaining good quality of the lipids for biodiesel production.

  18. Batch sedimentation studies for freshwater green alga Scenedesmus abundans using combination of flocculants

    Science.gov (United States)

    Moorthy, Raghu K.; Premalatha, M.; Arumugam, Muthu

    2017-06-01

    Microalga is the only feedstock that has the theoretical potential to completely replace the energy requirements derived from fossil fuels. However, commercialization of this potential source for fuel applications is hampered due to many technical challenges with harvesting of biomass being the most energy intensive process among them. The fresh water microalgal species, Scenedesmus abundans, has been widely recognized as a potential feedstock for production of biodiesel (Mandotra et al., 2014). The present work deals with sedimentation of algal biomass using extracted chitosan and natural bentonite clay powder as flocculant. The effect of flocculant combination and different factors such as temperature, pH and concentration of algal biomass on sedimentation rates has been analyzed. A high flocculation efficiency of 76.22 + 7.81% was obtained at an algal biomass concentration of 1 + 0.05 g/L for a settling time of 1 hour at 50 + 5oC with a settling velocity of 103.2 + 0.6 cm/h and a maximum surface conductivity of 2260 + 2 µS/cm using an optimal design in response surface methodology (RSM). Biopolymer flocculant such as chitosan exhibited better adsorption property along with bentonite clay powder that reduced the settling time significantly.

  19. A Green Algae Mixture of Scenedesmus and Schroederiella Attenuates Obesity-Linked Metabolic Syndrome in Rats

    Science.gov (United States)

    Kumar, Senthil Arun; Magnusson, Marie; Ward, Leigh C.; Paul, Nicholas A.; Brown, Lindsay

    2015-01-01

    This study investigated the responses to a green algae mixture of Scenedesmus dimorphus and Schroederiella apiculata (SC) containing protein (46.1% of dry algae), insoluble fibre (19.6% of dry algae), minerals (3.7% of dry algae) and omega-3 fatty acids (2.8% of dry algae) as a dietary intervention in a high carbohydrate, high fat diet-induced metabolic syndrome model in four groups of male Wistar rats. Two groups were fed with a corn starch diet containing 68% carbohydrates as polysaccharides, while the other two groups were fed a diet high in simple carbohydrates (fructose and sucrose in food, 25% fructose in drinking water, total 68%) and fats (saturated and trans fats from beef tallow, total 24%). High carbohydrate, high fat-fed rats showed visceral obesity with hypertension, insulin resistance, cardiovascular remodelling, and nonalcoholic fatty liver disease. SC supplementation (5% of food) lowered total body and abdominal fat mass, increased lean mass, and attenuated hypertension, impaired glucose and insulin tolerance, endothelial dysfunction, infiltration of inflammatory cells into heart and liver, fibrosis, increased cardiac stiffness, and nonalcoholic fatty liver disease in the high carbohydrate, high fat diet-fed rats. This study suggests that the insoluble fibre or protein in SC helps reverse diet-induced metabolic syndrome. PMID:25875119

  20. Optimization of Alkaline Flocculation for Harvesting of Scenedesmus quadricauda #507 and Chaetoceros muelleri #862

    Directory of Open Access Journals (Sweden)

    Shuhao Huo

    2014-09-01

    Full Text Available A response surface methodology (RSM was used to evaluate the effects of pH and microalgal biomass concentration (BC on alkaline flocculating activity for harvesting one freshwater green algae Scenedesmus quadricauda #507 and one marine diatom Chaetoceros muelleri #862. The pH value and BC were in range of 9.0–12.0 and 0.20–2.30 g/L, respectively. Very high regression coefficient between the variables and the response indicates excellent evaluation of experimental data by second-order regressions. Optimum conditions for flocculating activity were estimated as follows: (i pH 11.6, BC 0.54 g/L for strain #507 and (ii pH 11.5, BC 0.42 g/L for strain #862. The maximum flocculating activity was around 94.7% and 100%, respectively. Furthermore, the addition of synthetic ocean water (SOW to the freshwater #507 culture can increase the flocculating activity from 82.13%–88.79% in low algae concentration (0.52 g/L and 82.92%–95.60% in high concentration (2.66 g/L.

  1. Low light intensity and nitrogen starvation modulate the chlorophyll content of Scenedesmus dimorphus.

    Science.gov (United States)

    Ferreira, V S; Pinto, R F; Sant'Anna, C

    2016-03-01

    Chlorophyll is a photosynthetic pigment found in plants and algal organisms and is a bioproduct with human health benefits and a great potential for use in the food industry. The chlorophyll content in microalgae strains varies in response to environmental factors. In this work, we assessed the effect of nitrogen depletion and low light intensity on the chlorophyll content of the Scenedesmus dimorphus microalga. The growth of S. dimorphus under low light intensity led to a reduction in cell growth and volume as well as increased cellular chlorophyll content. Nitrogen starvation led to a reduction in cell growth and the chlorophyll content, changes in the yield and productivity of chlorophylls a and b. Transmission electron microscopy was used to investigate the ultrastructural changes in the S. dimorphus exposed to nitrogen and light deficiency. In contrast to nitrogen depletion, low light availability was an effective mean for increasing the total chlorophyll content of green microalga S. dimorphus. The findings acquired in this work are of great biotechnological importance to extend knowledge of choosing the right culture condition to stimulate the effectiveness of microalgae strains for chlorophyll production purposes. © 2015 The Society for Applied Microbiology.

  2. Feasibility of using brewery wastewater for biodiesel production and nutrient removal by Scenedesmus dimorphus.

    Science.gov (United States)

    Lutzu, Giovanni Antonio; Zhang, Wei; Liu, Tianzhong

    2016-01-01

    This work investigates the potential use of a brewery wastewater as a medium for the cultivation of the oleaginous species Scenedesmus dimorphus with the double aim of removing nutrients and to produce biomass as feedstock for biodiesel. For this purpose, effects of nitrogen (61.8-247 mg L(-1)), phosphorous (1.4-5.5 mg L(-1)), and iron (1.5-6 mg L(-1)) concentrations on growth, nutrients uptake, lipid accumulation, and fatty acids profile of this microalga were investigated. Results showed that brewery wastewater can be used as a culture medium even if nitrogen and phosphorous concentrations should have been modified to improve both biomass (6.82 g L(-1)) and lipid accumulation (44.26%). The analysis revealed a C16-C18 composition of 93.47% fatty acids methyl esters with a relative high portion of unsaturated ones (67.24%). High removal efficiency (>99%) for total nitrogen and total phosphorous and a reduction of up to 65% in chemical oxygen demand were achieved, respectively. The final microalgae biomass, considering its high lipid content as well as its compliance with the standards for the quality of biodiesel, and considering also the high removal efficiencies obtained for macronutrients and organic carbon, makes the brewery wastewater a viable option as a priceless medium for the cultivation of microalgae.

  3. Zinc-induced differential oxidative stress and antioxidant responses in Chlorella sorokiniana and Scenedesmus acuminatus.

    Science.gov (United States)

    Hamed, Seham M; Zinta, Gaurav; Klöck, Gerd; Asard, Han; Selim, Samy; AbdElgawad, Hamada

    2017-06-01

    Algae are frequently exposed to toxic metals, and zinc (Zn) is one of the major toxicants present. We exposed two green microalgae, Chlorella sorokiniana and Scenedesmus acuminatus, to sub-lethal concentrations (1.0 and 0.6mM) of Zn for seven days. Algal responses were analysed at the level of growth, oxidative stress, and antioxidants. Growth parameters such as cell culture yield and pigment content were less affected by Zn in C. sorokiniana, despite the fact that this alga accumulated more zinc than S. acuminatus. Also, C. sorokiniana, but not S. acuminatus, was able to acclimatize during long-term exposure to toxic concentrations of the test metals (specific growth rate (µ) was 0.041/day and total chlorophyll was 14.6mg/mL). Although, Zn induced oxidative stress in both species, C. sorokiniana experienced less stress than S. acuminatus. This could be explained by a higher accumulation of antioxidants in C. sorokiniana, where flavonoids, polyphenols, tocopherols, glutathione (GSH) and ascorbate (ASC) content increased. Moreover, antioxidant enzymes glutathione S transferase (GST), glutathione reductase (GR), superoxide dismutase (SOD), peroxidase (POX) and ascorbate peroxidase (APX), showed increased activities in C. sorokiniana. In addition to, and probably also underlying, the higher Zn tolerance in C. sorokiniana, this alga also showed higher Zn biosorption capacity. Use of C. sorokiniana as a bio-remediator, could be considered. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Batch Sedimentation Studies for Freshwater Green Alga Scenedesmus abundans Using Combination of Flocculants

    Directory of Open Access Journals (Sweden)

    Raghu K. Moorthy

    2017-06-01

    Full Text Available Microalga is the only feedstock that has the theoretical potential to completely replace the energy requirements derived from fossil fuels. However, commercialization of this potential source for fuel applications is hampered due to many technical challenges with harvesting of biomass being the most energy intensive process among them. The fresh water microalgal species, Scenedesmus abundans, has been widely recognized as a potential feedstock for production of biodiesel (Mandotra et al., 2014. The present work deals with sedimentation of algal biomass using extracted chitosan and natural bentonite clay powder as flocculant. The effect of flocculant combination and different factors such as temperature, pH, and concentration of algal biomass on sedimentation rates has been analyzed. A high flocculation efficiency of 76.22 ± 7.81% was obtained at an algal biomass concentration of 1 ± 0.05 g/L for a settling time of 1 h at 50 ± 5°C with a settling velocity of 103.2 ± 0.6 cm/h and a maximum surface conductivity of 2,260 ± 2 μS/cm using an optimal design in response surface methodology (RSM. Biopolymer flocculant such as chitosan exhibited better adsorption property along with bentonite clay powder that reduced the settling time significantly.

  5. Fresh water green microalga Scenedesmus abundans: A potential feedstock for high quality biodiesel production.

    Science.gov (United States)

    Mandotra, S K; Kumar, Pankaj; Suseela, M R; Ramteke, P W

    2014-03-01

    Present investigation studied the potential of fresh water green microalga Scenedesmus abundans as a feedstock for biodiesel production. To study the biomass and lipid yield, the culture was grown in BBM, Modified CHU-13 and BG-11 medium. Among the tested nitrogen concentration using Modified CHU-13 medium, the highest biomass and lipid yield of 1.113±0.05g/L and 489±23mg/L respectively was found in the culture medium with 0.32g/L of nitrogen (KNO3). Different lipid extraction as well as transesterification methods were also tested. Fatty acid profile of alga grown in large scale indigenous made photobioreactor has shown abundance of fatty acids with carbon chain length of C16 and C18. Various biodiesel properties such as cetane number, iodine value and saponification value were found to be in accordance with Brazilian National Petroleum Agency (ANP255) and European biodiesel standard EN14214 which makes S. abundans as a potential feedstock for biodiesel production. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Enhancement of Lipid Extraction from Marine Microalga, Scenedesmus Associated with High-Pressure Homogenization Process

    Science.gov (United States)

    Cho, Seok-Cheol; Choi, Woon-Yong; Oh, Sung-Ho; Lee, Choon-Geun; Seo, Yong-Chang; Kim, Ji-Seon; Song, Chi-Ho; Kim, Ga-Vin; Lee, Shin-Young; Kang, Do-Hyung; Lee, Hyeon-Yong

    2012-01-01

    Marine microalga, Scenedesmus sp., which is known to be suitable for biodiesel production because of its high lipid content, was subjected to the conventional Folch method of lipid extraction combined with high-pressure homogenization pretreatment process at 1200 psi and 35°C. Algal lipid yield was about 24.9% through this process, whereas only 19.8% lipid can be obtained by following a conventional lipid extraction procedure using the solvent, chloroform : methanol (2 : 1, v/v). Present approach requires 30 min process time and a moderate working temperature of 35°C as compared to the conventional extraction method which usually requires >5 hrs and 65°C temperature. It was found that this combined extraction process followed second-order reaction kinetics, which means most of the cellular lipids were extracted during initial periods of extraction, mostly within 30 min. In contrast, during the conventional extraction process, the cellular lipids were slowly and continuously extracted for >5 hrs by following first-order kinetics. Confocal and scanning electron microscopy revealed altered texture of algal biomass pretreated with high-pressure homogenization. These results clearly demonstrate that the Folch method coupled with high-pressure homogenization pretreatment can easily destruct the rigid cell walls of microalgae and release the intact lipids, with minimized extraction time and temperature, both of which are essential for maintaining good quality of the lipids for biodiesel production. PMID:22969270

  7. Effects of simulated flue gas on components of Scenedesmus raciborskii WZKMT.

    Science.gov (United States)

    Li, Xie-kun; Xu, Jing-liang; Guo, Ying; Zhou, Wei-zheng; Yuan, Zhen-hong

    2015-08-01

    Scenedesmus raciborskii WZKMT cultured with simulated flue gas was investigated. Cellular components, including total sugar, starch, chlorophyll, protein and lipid, were compared between simulated flue gas and 7% (v/v) CO2. Dissolution of SO2 and NO in simulated flue gas led to pH decrease and toxicity to microalgae cells. Furthermore, the death or aging of microalgae cells reduced the buffer capacity and caused decrease of simulated flue gas absorption. With 7% CO2, the highest total sugar and starch content could attain to 66.76% and 53.16%, respectively, which indicated S. raciborskii WZKMT is a desired feedstock candidate for bioethanol production. Microalgae growth and starch accumulation was inhibited, while cells produced more chlorophyll, protein and lipid when simulated flue gas was the carbon source. Fatty acids composition analysis indicated that there was no significant distinction on fatty acids relative content (fatty acid/TFA) between cells aerated using simulated flue gas and 7% CO2. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Two stage heterotrophy/photoinduction culture of Scenedesmus incrassatulus: potential for lutein production.

    Science.gov (United States)

    Flórez-Miranda, Liliana; Cañizares-Villanueva, Rosa Olivia; Melchy-Antonio, Orlando; Martínez-Jerónimo, Fernando; Flores-Ortíz, Cesar Mateo

    2017-11-20

    A biomass production process including two stages, heterotrophy/photoinduction (TSHP), was developed to improve biomass and lutein production by the green microalgae Scenedesmus incrassatulus. To determine the effects of different nitrogen sources (yeast extract and urea) and temperature in the heterotrophic stage, experiments using shake flask cultures with glucose as the carbon source were carried out. The highest biomass productivity and specific pigment concentrations were reached using urea+vitamins (U+V) at 30°C. The first stage of the TSHP process was done in a 6L bioreactor, and the inductions in a 3L airlift photobioreactor. At the end of the heterotrophic stage, S. incrassatulus achieved the maximal biomass concentration, increasing from 7.22gL-1 to 17.98gL-1 with an increase in initial glucose concentration from 10.6gL-1 to 30.3gL-1. However, the higher initial glucose concentration resulted in a lower specific growth rate (μ) and lower cell yield (Yx/s), possibly due to substrate inhibition. After 24h of photoinduction, lutein content in S. incrassatulus biomass was 7 times higher than that obtained at the end of heterotrophic cultivation, and the lutein productivity was 1.6 times higher compared with autotrophic culture of this microalga. Hence, the two-stage heterotrophy/photoinduction culture is an effective strategy for high cell density and lutein production in S. incrassatulus. Copyright © 2017. Published by Elsevier B.V.

  9. Batch Sedimentation Studies for Freshwater Green Alga Scenedesmus abundans Using Combination of Flocculants.

    Science.gov (United States)

    Moorthy, Raghu K; Premalatha, M; Arumugam, Muthu

    2017-01-01

    Microalga is the only feedstock that has the theoretical potential to completely replace the energy requirements derived from fossil fuels. However, commercialization of this potential source for fuel applications is hampered due to many technical challenges with harvesting of biomass being the most energy intensive process among them. The fresh water microalgal species, Scenedesmus abundans, has been widely recognized as a potential feedstock for production of biodiesel (Mandotra et al., 2014). The present work deals with sedimentation of algal biomass using extracted chitosan and natural bentonite clay powder as flocculant. The effect of flocculant combination and different factors such as temperature, pH, and concentration of algal biomass on sedimentation rates has been analyzed. A high flocculation efficiency of 76.22 ± 7.81% was obtained at an algal biomass concentration of 1 ± 0.05 g/L for a settling time of 1 h at 50 ± 5°C with a settling velocity of 103.2 ± 0.6 cm/h and a maximum surface conductivity of 2,260 ± 2 μS/cm using an optimal design in response surface methodology (RSM). Biopolymer flocculant such as chitosan exhibited better adsorption property along with bentonite clay powder that reduced the settling time significantly.

  10. Batch Sedimentation Studies for Freshwater Green Alga Scenedesmus abundans Using Combination of Flocculants

    Science.gov (United States)

    Moorthy, Raghu K.; Premalatha, M.; Arumugam, Muthu

    2017-01-01

    Microalga is the only feedstock that has the theoretical potential to completely replace the energy requirements derived from fossil fuels. However, commercialization of this potential source for fuel applications is hampered due to many technical challenges with harvesting of biomass being the most energy intensive process among them. The fresh water microalgal species, Scenedesmus abundans, has been widely recognized as a potential feedstock for production of biodiesel (Mandotra et al., 2014). The present work deals with sedimentation of algal biomass using extracted chitosan and natural bentonite clay powder as flocculant. The effect of flocculant combination and different factors such as temperature, pH, and concentration of algal biomass on sedimentation rates has been analyzed. A high flocculation efficiency of 76.22 ± 7.81% was obtained at an algal biomass concentration of 1 ± 0.05 g/L for a settling time of 1 h at 50 ± 5°C with a settling velocity of 103.2 ± 0.6 cm/h and a maximum surface conductivity of 2,260 ± 2 μS/cm using an optimal design in response surface methodology (RSM). Biopolymer flocculant such as chitosan exhibited better adsorption property along with bentonite clay powder that reduced the settling time significantly. PMID:28674686

  11. Enhancement of nutrient removal from swine wastewater digestate coupled to biogas purification by microalgae Scenedesmus spp.

    Science.gov (United States)

    Prandini, Jean Michel; da Silva, Márcio Luís Busi; Mezzari, Melissa Paola; Pirolli, Mateus; Michelon, William; Soares, Hugo Moreira

    2016-02-01

    This work investigated the effects of swine wastewater-derived biogas on microalgae biomass production and nutrient removal rates from piggery wastewater concomitantly with biogas filtration. Photobioreactors with dominant Scenedesmus spp. were prepared using non-sterile digestate and exposed to different photoperiods. In the presence of biogas and autotrophic conditions microalgae yield of 1.1±0.2 g L(-1) (growth rate of 141.8±3.5 mg L(-1) d(-1)) was obtained leading to faster N-NH3 and P-PO4(3-) assimilation rate of 21.2±1.2 and 3.5±2.5 mg L(-1) d(-1), respectively. H2S up to 3000 ppmv was not inhibitory and completely removed. Maximum CO2 assimilation of 219±4.8 mg L(-1) d(-1) was achieved. Biological consumption of CH4 up to 18% v/v was verified. O2 up to 22% v/v was controlled by adding acetate to exacerbate oxygen demand by microorganisms. Microalgae-based wastewater treatment coupled to biogas purification accelerates nutrient removal concomitantly producing valuable biomass and biomethane. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Sorption Capacity Measurement of Chlorella Vulgaris and Scenedesmus Acutus to Remove Chromium from Tannery Waste Water

    Science.gov (United States)

    Ardila, Liliana; Godoy, Rubén; Montenegro, Luis

    2017-08-01

    Tanning process is a polluting activity due to the release of toxic agents into the environment. One of the most important of those toxic chemicals is chromium. Different alternatives have been proposed for the removal of this metal from tanning waste water which include the optimization of the productive processes, physicochemical and biochemical waste water treatment. In this study, the biological adsorption process of trivalent chromium was carried out in synthetic water and tannery waste water through two types of native green microalgae, called Chlorella vulgaris and Scenedesmus acutus in Free State and immobilized in PVA state. This, considering that cellular wall of microalgae has functional groups like amines and carboxyl that might bind with trivalent chromium. Statistical significance of variables as pH temperature, chromium and algae concentrations was evaluated just like bio sorption capacity of different types of water and kind of bioadsorbent was calculated to determine if this process is a competitive solution comparing to other heavy metal removal processes.

  13. Effect of cadmium on cellular viability in two species of microalgae (Scenedesmus sp. and Dunaliella viridis).

    Science.gov (United States)

    Marcano, Letty Beatriz C; Carruyo, Ingrid M; Montiel, Xiomara M; Morales, Carolina B; de Soto, Patricia Moreno

    2009-07-01

    We determined the effect of several concentrations of cadmium (0, 5, 10, and 20 microg/l) on cellular viability in the microalgae Scenedesmus sp. and Dunaliella viridis, by measuring growth at 0, 24, 48, 72, and 96 h and pigment production at 10 days. Algae were obtained from the Nonvascular Plant Laboratory collection, in the Facultad Experimental de Ciencias, Universidad del Zulia, Venezuela. Growth was measured by cellular counting, while pigment content was evaluated using conventional spectrophotometric techniques. Growth of both species decreased in the exposed cultures comparing with the control, but its behavior was similar, because in both control and exposed cultures, its was observed an adaptive phase in the first hours, as well as a growth phase after 72 h. Cadmium concentrations above 10 microg/l produced an adverse effect on pigment production, depending on the concentration and/or exhibition time. However, even though cadmium inhibited growth and pigment production, levels of both parameters indicated cellular viability, demonstrating the adaptability of the algae cultures when they were exposed to the metal.

  14. A Green Algae Mixture of Scenedesmus and Schroederiella Attenuates Obesity-Linked Metabolic Syndrome in Rats

    Directory of Open Access Journals (Sweden)

    Senthil Arun Kumar

    2015-04-01

    Full Text Available This study investigated the responses to a green algae mixture of Scenedesmus dimorphus and Schroederiella apiculata (SC containing protein (46.1% of dry algae, insoluble fibre (19.6% of dry algae, minerals (3.7% of dry algae and omega-3 fatty acids (2.8% of dry algae as a dietary intervention in a high carbohydrate, high fat diet-induced metabolic syndrome model in four groups of male Wistar rats. Two groups were fed with a corn starch diet containing 68% carbohydrates as polysaccharides, while the other two groups were fed a diet high in simple carbohydrates (fructose and sucrose in food, 25% fructose in drinking water, total 68% and fats (saturated and trans fats from beef tallow, total 24%. High carbohydrate, high fat-fed rats showed visceral obesity with hypertension, insulin resistance, cardiovascular remodelling, and nonalcoholic fatty liver disease. SC supplementation (5% of food lowered total body and abdominal fat mass, increased lean mass, and attenuated hypertension, impaired glucose and insulin tolerance, endothelial dysfunction, infiltration of inflammatory cells into heart and liver, fibrosis, increased cardiac stiffness, and nonalcoholic fatty liver disease in the high carbohydrate, high fat diet-fed rats. This study suggests that the insoluble fibre or protein in SC helps reverse diet-induced metabolic syndrome.

  15. Cultivating Chlorella vulgaris and Scenedesmus quadricauda microalgae to degrade inorganic compounds and pesticides in water.

    Science.gov (United States)

    Baglieri, Andrea; Sidella, Sarah; Barone, Valeria; Fragalà, Ferdinando; Silkina, Alla; Nègre, Michèle; Gennari, Mara

    2016-09-01

    This work evaluates the possibility of cultivating Scenedesmus quadricauda and Chlorella vulgaris microalgae in wastewater from the hydroponic cultivation of tomatoes with the aim of purifying the water. S. quadricauda and C. vulgaris were also used in purification tests carried out on water contaminated by the following active ingredients: metalaxyl, pyrimethanil, fenhexamid, iprodione, and triclopyr. Fifty-six days after the inoculum was placed, a reduction was found in the concentration of nitric nitrogen, ammonia nitrogen, and soluble and total phosphorus. The decrease was 99, 83, 94, and 94 %, respectively, for C. vulgaris and 99, 5, 88, and 89 %, respectively, for S. quadricauda. When the microalgae were present, all the agrochemicals tested were removed more quickly from the water than from the sterile control (BG11). The increase in the rate of degradation was in the order metalaxyl > fenhexamid > iprodione > triclopyr > pyrimethanil. It was demonstrated that there was a real degradation of fenhexamid, metalaxyl, triclopyr, and iprodione, while in the case of pyrimethanil, the active ingredient removed from the substrate was absorbed onto the cells of the microalgae. It was also found that the agrochemicals used in the tests had no significant effect on the growth of the two microalgae. The experiment highlighted the possibility of using cultivations of C. vulgaris and S. quadricauda as purification systems for agricultural wastewater which contains eutrophic inorganic compounds such as nitrates and phosphates and also different types of pesticides.

  16. Biomass production of a Scenedesmus sp. under phosphorous-starvation cultivation condition.

    Science.gov (United States)

    Yin-Hu, Wu; Yin, Yu; Xin, Li; Hong-Ying, Hu; Zhen-Feng, Su

    2012-05-01

    Microalgae-based bioenergy has gained extensive attention, but the consumption of non-renewable resource such as phosphorous is inevitable in the production of its feedstock. In this work, the minimal phosphorous consumption for algal biomass production of Scenedesmus sp. LX1 was investigated by monitoring the growth and nutrient uptake under two different cultivation modes: phosphorous-starvation and luxury-nutrient. The results showed that continuous nitrogen and phosphorous feeding in luxury-nutrient mode had no stimulating effect on biomass productivity at the nutrient level in this study, TN: 245 mg L(-1), TP: 5.4 mg L(-1). However, the sustained growth of biomass after the exhaust of phosphate in phosphorous-starvation mode led to significant increase in the biomass yield of phosphorous up to 160 g biomass/g -P, which was nearly six times more than that with nutrient feeding. To minimize phosphorous resource consumption in production of algal biomass, a phosphorous-starvation cultivation mode is proposed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Selective degradation of the recalcitrant cell wall of Scenedesmus quadricauda CASA CC202.

    Science.gov (United States)

    Reshma, Ragini; Arumugam, Muthu

    2017-07-06

    An eco-friendly cell wall digestion strategy was developed to enhance the availability of nutritionally important bio molecules of edible microalgae and exploit them for cloning, transformation, and expression of therapeutic proteins. Microalgae are the source for many nutritionally important bioactive compounds and potential drugs. Even though edible microalgae are rich in nutraceutical, bioavailability of all these molecules is very less due to their rigid recalcitrant cell wall. For example, the cell wall of Scenedesmus quadricauda CASA CC202 is made up of three layers comprising of rigid outer pectin and inner cellulosic layer separated by a thin middle layer. In the present investigation, a comprehensive method has been developed for the selective degradation of S. quadricauda CASA CC202 cell wall, by employing both mechanical and enzymatic treatments. The efficiency of cell wall removal was evaluated by measuring total reducing sugar (TRS), tannic acid-ferric chloride staining, calcoflour white staining, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) analysis. It was confirmed that the yield of TRS increased from 129.82 mg/g in 14 h from pectinase treatment alone to 352.44 mg/g by combined sonication and enzymatic treatment within 12 h. As a result, the combination method was found to be effective for the selective degradation of S. quadricauda CASA CC202 cell wall. This study will form a base for our future works, where this will help to enhance the digestibility and availability of nutraceutically important proteins.

  18. o-PHENANTHROLINE AND DERIVATIVES OF VITAMIN K AS STABILIZERS OF PHOTOREDUCTION IN SCENEDESMUS.

    Science.gov (United States)

    Gaffron, H

    1945-01-20

    It is known that with increasing concentrations of hydroxylamine the rate of photoreduction in the alga Scenedesmus drops to about one-half of the normal rate. From then on photoreduction remains insensitive to hydroxylamine. The present experiments prove that this strange effect is not specific for hydroxylamine. It can be produced with substances having quite different chemical properties, such as o-phenanthroline, 2-methyl-1,4-naphthoquinone (vitamin K), or 2-oxy-3-methyl-naphthoquinone (phthiocol). Once the rate of photoreduction has been brought down to the limit of exactly one-half by a sufficient dose of any one of these substances, the reaction is also stabilized against reversion under the influence of strong light. At saturation intensities the rate of the stabilized photoreduction may be several times that at which the unpoisoned cells revert to photosynthesis. The ratio of one-half between the rates of the stabilized and the normal photoreduction is found at very low light intensities. This indicates a change in the photochemical process. Since the assimilatory quotient remains unaltered, it is the quantum yield which is cut in half under the influence of the poisons. To explain these observations it is assumed that either just one-half of the primary photoproducts are lost, or that they react back entirely while causing a reduction of carbon dioxide in a way similar to that brought about by the oxyhydrogen reaction in the dark.

  19. Enhanced biofuel production potential with nutritional stress amelioration through optimization of carbon source and light intensity in Scenedesmus sp. CCNM 1077.

    Science.gov (United States)

    Pancha, Imran; Chokshi, Kaumeel; Mishra, Sandhya

    2015-03-01

    Microalgal mixotrophic cultivation is one of the most potential ways to enhance biomass and biofuel production. In the present study, first of all ability of microalgae Scenedesmus sp. CCNM 1077 to utilize various carbon sources under mixotrophic growth condition was evaluated followed by optimization of glucose concentration and light intensity to obtain higher biomass, lipid and carbohydrate contents. Under optimized condition i.e. 4 g/L glucose and 150 μmol m(-2) s(-1) light intensity, Scenedesmus sp. CCNM 1077 produced 1.2g/L dry cell weight containing 23.62% total lipid and 42.68% carbohydrate. Addition of glucose shown nutritional stress ameliorating effects and around 70% carbohydrate and 25% total lipid content was found with only 21% reduction in dry cell weight under nitrogen starved condition. This study shows potential application of mixotrophically grown Scenedesmus sp. CCNM 1077 for bioethanol and biodiesel production feed stock. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Delayed onset of electromyographic activity of vastus medialis obliquus relative to vastus lateralis in subjects with patellofemoral pain syndrome.

    Science.gov (United States)

    Cowan, S M; Bennell, K L; Hodges, P W; Crossley, K M; McConnell, J

    2001-02-01

    To determine whether electromyographic (EMG) onsets of vastus medialis obliquus (VMO) and vastus lateralis (VL) are altered in the presence of patellofemoral pain syndrome (PFPS) during the functional task of stair stepping. Cross-sectional. University laboratory. Thirty-three subjects with PFPS and 33 asymptomatic controls. Subjects ascended and descended a set of stairs-2 steps, each 20-cm high-at usual stair-stepping pace. EMG readings of VMO and VL taken on middle stair during step up (concentric contraction) and step down (eccentric contraction). Relative difference in onset of surface EMG activity of VMO compared with VL during a stair-stepping task. EMG onsets were determined by using a computer algorithm and were verified visually. In the PFPS population, the EMG onset of VL occurred before that of VMO in both the step up and step down phases of the stair-stepping task (p EMG activity of VMO and VL in either phase of the task for the control subjects. This finding supports the hypothesized relationship between changes in the timing of activity of the vastimuscles and PFPS. This finding provides theoretical rationale to support physiotherapy treatment commonly used in the management of PFPS.

  1. Use of scenedesmus for the removal of nutrients and heavy metals from waste waters of the textile industry

    OpenAIRE

    Pérez Silva, Karen Rocío; Vega Bolaños, Asly Michell; Hernández Rodríguez, Luisa Carolina; Parra Ospina, David Alejandro; Ballen Segura, Miguel Ángel

    2016-01-01

    Introduction: This article is a derivative research product from the project “Use of waste waters as alternative substrate to generate microalgae biomass”, developed by the Environmental and Bioprocessing Engineering Research Incubator (SIIAB) of the Universidad Sergio Arboleda. The project was implemented during the year 2015. The objective of the research was to evaluate the use microalgae Scenedesmus sp. as a processing tool of industrial waste waters produced in a textile company located ...

  2. Differential effects of P25 TiO{sub 2} nanoparticles on freshwater green microalgae: Chlorella and Scenedesmus species

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Rajdeep; Parashar, Abhinav; Bhuvaneshwari, M.; Chandrasekaran, N.; Mukherjee, Amitava, E-mail: amit.mookerjea@gmail.com

    2016-07-15

    Highlights: • Differential effects of P25 TiO{sub 2} NPs on Chlorella and Scenedesmus. • Concentration dependent effects in morphology and viability. • Increased ROS, catalase activity & LPO release with loss in SOD & GSH activity. • Dose dependent differential TiO{sub 2} NPs uptake affected by colonization of algae. - Abstract: P25 TiO{sub 2} nanoparticles majorly used in cosmetic products have well known detrimental effects towards the aquatic environment. In a freshwater ecosystem, Chlorella and Scenedesmus are among the most commonly found algal species frequently used to study the effects of metal oxide nanoparticles. A comparative study has been conducted herein to investigate differences in the toxic effects caused by these nanoparticles towards the two algae species. The three different concentrations of P25 TiO{sub 2} NPs (0.01, 0.1 & 1 μg/mL, i.e., 0.12, 1.25 and 12.52 μM) were selected to correlate surface water concentrations of the nanoparticles, and filtered and sterilized fresh water medium was used throughout this study. There was significant increase (p < 0.001) in hydrodynamic diameter of nanoparticles with respect to both, time (0, 24, 48 and 72 h) as well as concentration under all the exposure conditions. Although, significant dose-dependent morphological (surface area & biovolume) interspecies variations were not observed, it was evident at the highest concentration of exposure within individuals. At 1 μg/mL exposure concentration, a significant difference in toxicity was noted between Chlorella and Scenedesmus under only visible light (p < 0.001) and UVA (p < 0.01) irradiation conditions. The viability data were well supported by the results obtained for oxidative stress induced by NPs on the cells. At the highest exposure concentration, superoxide dismutase and reduced glutathione activities were assessed for both the algae under all the irradiation conditions. Increased catalase activity and LPO release complemented the cytotoxic

  3. Probing the elastic response of microalga Scenedesmus dimorphus in dry and aqueous environments through atomic force microscopy

    Science.gov (United States)

    Warren, K. M.; Mpagazehe, J. N.; LeDuc, P. R.; Higgs, C. F.

    2014-10-01

    With the re-emergence of microalgae as a replacement feedstock for petroleum-derived oils, researchers are working to understand its chemical and mechanical behavior. In this work, the mechanical properties of microalgae, Scenedesmus dimorphus, were investigated at the subcellular level to determine the elastic response of cells that were in an aqueous and dried state using nano-scale indentation through atomic force microscopy. The elastic modulus of single-celled S. dimorphus cells increased over tenfold from an aqueous state to a dried state, which allows us to better understand the biophysical response of microalgae to stress.

  4. Probing the elastic response of microalga Scenedesmus dimorphus in dry and aqueous environments through atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Warren, K. M.; Mpagazehe, J. N.; Higgs, C. F., E-mail: prl@andrew.cmu.edu, E-mail: higgs@andrew.cmu.edu [Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, Pennsylvania 15213 (United States); LeDuc, P. R., E-mail: prl@andrew.cmu.edu, E-mail: higgs@andrew.cmu.edu [Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, Pennsylvania 15213 (United States); Departments of Biomedical Engineering and Biological Sciences, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213 (United States)

    2014-10-20

    With the re-emergence of microalgae as a replacement feedstock for petroleum-derived oils, researchers are working to understand its chemical and mechanical behavior. In this work, the mechanical properties of microalgae, Scenedesmus dimorphus, were investigated at the subcellular level to determine the elastic response of cells that were in an aqueous and dried state using nano-scale indentation through atomic force microscopy. The elastic modulus of single-celled S. dimorphus cells increased over tenfold from an aqueous state to a dried state, which allows us to better understand the biophysical response of microalgae to stress.

  5. Cultivo de las microalgas dulceacuícolas Kirchneriella obesa, Scenedesmus quadricauda y Chlorococcum infusorium empleando tres medios de cultivo

    OpenAIRE

    Ortega-Salas, A. A.; Reyes-Bustamante, H.

    2012-01-01

    Se cultivaron las microalgas dulceacuícolas Kirchneriella obesa (G. S. West) Schmidle 1893, Scenedesmus quadricauda (Chodat, Turpin) Bréb 1835 y Chlorococcum infusorium (Schrank) Meneghini 1842, con el propósito comparar las tasas de crecimiento y su rendimiento en tres medios de cultivo, el F/2 de Guillard, Fert I y Fert II. El agua utilizada se pasó en filtros de cinco, uno y 0.45 mm, y se trató con luz ultravioleta. La temperatura varió de 24 a 25°C. Se cultivaron en un sistema de volumen ...

  6. Cultivation of Scenedesmus dimorphus using anaerobic digestate as a nutrient medium.

    Science.gov (United States)

    Abu Hajar, Husam A; Riefler, R Guy; Stuart, Ben J

    2017-08-01

    In this study, the microalga Scenedesmus dimorphus was cultivated phototrophically using unsterilized anaerobic digestate as a nutrient medium. A bench-scale experiment was conducted by inoculating the microalga S. dimorphus with 0.05-10% dilutions of the anaerobic digestate supernatant. It was found that 1.25-2.5% dilutions, which is equivalent to 50-100 mg N/L total nitrogen concentrations and 6-12 mg P/L total phosphorus concentrations, provided sufficient nutrients to maximize the growth rate along with achieving high concentrations of algal biomass. The microalgae cultivation was scaled up to 100 L open raceway ponds, where the effect of paddlewheel mixing on the growth was investigated. It was concluded that 0.3 m/s water surface velocity yielded the highest specific growth rate and biomass concentration compared to 0.1 and 0.2 m/s. The microalga S. dimorphus was then cultivated in the raceway ponds using 2.5% diluted anaerobic digestate at 317 and 454 μmol/(m2 × s) average incident light intensities and 1.25% diluted anaerobic digestate at 234 and 384 μmol/(m2 × s) average incident light intensities. The maximum biomass concentration was 446 mg/L which was achieved in the 2.5% dilution and 454 μmol/(m2 × s) light intensity culture. Moreover, nitrogen, phosphorus, and COD removal efficiencies from the nutrient media were 65-72, 63-100, and 78-82%, respectively, whereas ammonia was completely removed from all cultures. For a successful and effective cultivation in open raceway ponds, light intensity has to be increased considerably to overcome the attenuation caused by the algal biomass as well as the suspended solids from the digestate supernatant.

  7. Cultivation of Scenedesmus dimorphus with domestic secondary effluent and energy evaluation for biodiesel production.

    Science.gov (United States)

    Zhang, S S; Liu, H; Fan, J F; Yu, H

    2015-01-01

    Microalgae cultivation in wastewater has gained significant attention as a cost-saving means for algae-based biofuel production. To evaluate the performance of Scenedesmus dimorphus cultivated in a 100-L continuously operated photobioreactor using domestic secondary effluent (DSE), algal growth, nutrients removal and energy evaluation were conducted in four scenarios. Prior to the application of continuous cultivation, S. dimorphus was grown in a batch operated 1.5-L bubble column photobioreactor to test the growth feasibility and lipids accumulation of S. dimorphus in DSE. The highest biomass achieved in DSE was 244 mg L(-1)with lipid content at 26.06%. Simultaneously, 98.72% of total phosphorus (TP) and 98.04% of total nitrogen (TN) in DSE were removed. Then, S. dimorphus were inoculated in the 100-L continuously operated photobioreactor using BG11, unsterilized DSE, N, P-added DSE and UV-sterilized DSE as the medium, respectively. Results showed that the highest biomass gained were 567, 174, 276 and 198 mg L(-1), respectively. TP removal rates in four scenarios were all above 90%. With adjustment to DSE, the overall TN removal rates increased up to 80%. Finally, energy evaluation demonstrated that although the case of BG11 as the medium provided the most energy production, the case using DSE with N and P supplementation was of the highest net energy rate, suggesting that microalgae cultivation for biodiesel production by DSE is of obvious potential and advantage over the synthesis medium like BG11.

  8. Age affects not only metabolome but also metal toxicity in Scenedesmus quadricauda cultures

    Energy Technology Data Exchange (ETDEWEB)

    Kováčik, Jozef, E-mail: jozkovacik@yahoo.com [Institute of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemědělská 1, 613 00 Brno (Czech Republic); CEITEC—Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, 613 00 Brno (Czech Republic); Klejdus, Bořivoj [Institute of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemědělská 1, 613 00 Brno (Czech Republic); CEITEC—Central European Institute of Technology, Mendel University in Brno, Zemědělská 1, 613 00 Brno (Czech Republic); Babula, Petr [Department of Physiology, Faculty of Medicine, Masaryk University, Kamenice 753/5, 625 00 Brno (Czech Republic); Hedbavny, Josef [Institute of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemědělská 1, 613 00 Brno (Czech Republic)

    2016-04-05

    Highlights: • Vitality was lower in old than in young culture and amount of sucrose differed. • Cd stimulated ROS more than Ni in both cultures but NO was not extensively affected. • Cd accumulated more than Ni but old culture contained more Cd and Ni than young. • Phytochelatin 2 strongly increased under Cd and ascorbic acid under Cd and high Ni. • Young culture contained more acids and mainly citrate differed under metal excess. - Abstract: Responses of Scenedesmus quadricauda grown in vitro and differing in age (old culture—13 months, young culture—1 month) to short-term cadmium (Cd) or nickel (Ni) excess (24 h) were compared. Higher age of the culture led to lower amount of chlorophylls, ascorbic acid and glutathione but higher signal of ROS. Surprisingly, sucrose was detected using DART-Orbitrap MS in both old and young culture and subsequent quantification confirmed its higher amount (ca. 3-times) in the old culture. Cd affected viability and ROS amount more negatively than Ni that could arise from excessive Cd uptake which was also higher in all treatments than in respective Ni counterparts. Surprisingly, nitric oxide was not extensively different in response to age or metals. Strong induction of phytochelatin 2 is certainly Cd-specific response while Ni also elevated ascorbate content. Krebs cycle acids were more accumulated in the young culture but they were rather elevated in the old culture (citric acid under Ni excess). We conclude that organic solid ‘Milieu Bristol’ medium we tested is suitable for long-term storage of unicellular green algae (also successfully tested for Coccomyxa sp. and Parachlorella sp.) and the impact of age on metal uptake may be useful for bioremediation purposes.

  9. Effect of temperature on growth and fatty acids profile of the biodiesel producing microalga Scenedesmus acutus

    Directory of Open Access Journals (Sweden)

    El-Sheekh, M.

    2017-01-01

    Full Text Available Description of the subject. The present study examined the effect of temperature (15, 20, 25, 30, 35 and 40 °C on biomass, esterified fatty acids content and fatty acid productivity of Scenedesmus acutus. Objectives. This work aimed to study the effect of variation in temperature on lipid productivity and fatty acid profiles of S. acutus as a feedstock for biodiesel production. Method. The alga was grown under different temperatures and its biomass, as well as fatty acid content and composition, were determined. Results. The maximum growth rate of S. acutus was achieved at 30 °C , but there was no significant difference in biomass productivity at 25 and 30 °C (0.41 and 0.42 g·l-1·d-1, respectively. The highest fatty acid content (104.1 mg·g-1 CDW was recorded at low temperature (15 °C and decreased with increasing temperature. As a result of high biomass production, fatty acids productivity showed the highest values (41.27 and 42.10 mg·l-1·d-1 at 25 and 30 °C, respectively. The proportion of saturated and mono-unsaturated fatty acids increased from 13.72 to 23.79% and from 11.13 to 33.10% of total fatty acids when the incubation temperature was raised from 15 to 40 °C, respectively. The increase of temperature from 15 to 40 °C decreased the poly-unsaturated fatty acids from 75.15% to 43.10% of total fatty acids, respectively. Conclusions. The present study concluded that incubation temperature was a critical parameter for quantitative and qualitative fatty acid compositions of S. acutus. In addition, the type and proportion of individual fatty acids, which interfere with biodiesel quality, can be modified using different incubation temperatures in order to meet the biodiesel international standards.

  10. Microalga Scenedesmus sp.: A potential low-cost green machine for silver nanoparticle synthesis.

    Science.gov (United States)

    Jena, Jayashree; Pradhan, Nilotpala; Nayak, Rati Ranjan; Dash, Bishnu P; Sukla, Lala Behari; Panda, Prasanna K; Mishra, Barada K

    2014-04-01

    Bionanotechnology has revolutionized nanomaterial synthesis by providing a green synthetic platform using biological systems. Among such biological systems, microalgae have tremendous potential to take up metal ions and produce nanoparticles by a detoxification process. The present study explores the intracellular and extracellular biogenic syntheses of silver nanoparticles (SNPs) using the unicellular green microalga Scenedesmus sp. Biosynthesized SNPs were characterized by AAS, UV-Vis spectroscopy, TEM, XRD, FTIR, DLS, and TGA studies and finally checked for antibacterial activity. Intracellular nanoparticle biosynthesis was initiated by a high rate of Ag(+) ion accumulation in the microalgal biomass and subsequent formation of spherical crystalline SNPs (average size, 15-20 nm) due to the biochemical reduction of Ag(+) ions. The synthesized nanoparticles were intracellular, as confirmed by the UV-Vis spectra of the outside medium. Furthermore, extracellular synthesis using boiled extract showed the formation of well scattered, highly stable, spherical SNPs with an average size of 5-10 nm. The size and morphology of the nanoparticles were confirmed by TEM. The crystalline nature of the SNPs was evident from the diffraction peaks of XRD and bright circular ring pattern of SAED. FTIR and UV-Vis spectra showed that biomolecules, proteins and peptides, are mainly responsible for the formation and stabilization of SNPs. Furthermore, the synthesized nanoparticles exhibited high antimicrobial activity against pathogenic gram-negative and gram-positive bacteria. Use of such a microalgal system provides a simple, cost-effective alternative template for the biosynthesis of nanomaterials in a large-scale system that could be of great use in biomedical applications.

  11. Carbon dioxide consumption of the microalga Scenedesmus obtusiusculus under transient inlet CO2 concentration variations.

    Science.gov (United States)

    Cabello, Juan; Morales, Marcia; Revah, Sergio

    2017-04-15

    The extensive microalgae diversity offers considerable versatility for a wide range of biotechnological applications in environmental and production processes. Microalgal cultivation is based on CO2 fixation via photosynthesis and, consequently, it is necessary to evaluate, in a short time and reliable way, the effect of the CO2 gas concentration on the consumption rate and establish the tolerance range of different strains and the amount of inorganic carbon that can be incorporated into biomass in order to establish the potential for industrial scale application. Dynamic experiments allow calculating the short-term microalgal photosynthetic activity of strains in photobioreactors. In this paper, the effect of step-changes in CO2 concentration fed to a 20L bubble column photobioreactor on the CO2 consumption rate of Scenedesmus obtusiusculus was evaluated at different operation times. The highest apparent CO2 consumption rate (336μmolm(-2)s(-1) and 5.6% of CO2) was 6530mgCO2gb(-1)d(-1) and it decreased to 222mgCO2gb(-1)d(-1) when biomass concentration increased of 0.5 to 3.1gbL(-1) and 5.6% of CO2 was fed. For low CO2 concentrations (<3.8%) the pH remained close to the optimal value (7.5 and 8). The CO2 consumption rates show that S. obtusiusculus was not limited by CO2 availability for concentrations above of 3.8%. The CO2 mass balance showed that 90% of the C-CO2 transferred was used for S. obtusiusculus growth. Copyright © 2017. Published by Elsevier B.V.

  12. KOMBINASI TEKNIK MULLIGAN DAN FASILITASI VASUS MEDIALIS OBLIQUUS LEBIH EFEKTIF MENINGKATKAN AKTIVITAS FUNGSIONAL DARIPADA APLIKASI KINESIO TAPING PADA SINDROMA NYERI SENDI PATELLOFEMORAL

    Directory of Open Access Journals (Sweden)

    Atika Yulianti

    2013-11-01

    Full Text Available Patellofemoral pain syndrome is complained of knee pain by young adults who are productive oftenly, syndrome characterized by pain that is felt around the kneecap, and aggravated the activity squat and stand, up and down stairs, and change the position of the knee after a long standstill ( stand up after sitting for a long time. This is due to the weakness of the thigh muscles especially vasus medialis obliquus. Reinforcement of weak muscle in particular strengthening of the vastus medialis  oblique an appropriate treatment to increase the functional activity of the syndrome. The study was a randomized experiment with pre and post-test group design. This study aimed to compare the combining of mulligan techniques and facilitate of vasus medialis obliquus with application of kinesio taping to increase the functional activity of the lower extremities. In this study, 11 respondents were given a combination of mulligan techniques and facilitation of vastus medialis oblique for 5 weeks with a frequency of exercise 3 times a week, and 11 respondents provided application of kinesio taping for 5 weeks with 3 days and replaced with a new taping. Each treatment was measured by the Lower Extremity Fungtional Scale before and after 5 weeks. Statistical analysis parametric paired sample t-test results is the influence of a combining of mulligan techniques and facilitate of vastus medialis oblique and application of kinesio taping to increase the functional activity of the lower extremities with p<0.05. Test of different with the independent sample t-test with a result there are significant difference between the combining of techniques mulligan and facilitation of vasus medialis obliquus with application of kinesio taping values with  p <0.05. Conclusions in this study that a combining of mulligan techniques and facilitation of vasus medialis obliquus, 3 times a week for 5 weeks effectively to increase the functional activity of the lower extremities of

  13. Effect of indigo dye effluent on the growth, biomass production and phenotypic plasticity of Scenedesmus quadricauda (Chlorococcales

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    MATHIAS A. CHIA

    2014-03-01

    Full Text Available The effect of indigo dye effluent on the freshwater microalga Scenedesmus quadricauda ABU12 was investigated under controlled laboratory conditions. The microalga was exposed to different concentrations of the effluent obtained by diluting the dye effluent from 100 to 175 times in bold basal medium (BBM. The growth rate of the microalga decreased as indigo dye effluent concentration increased (p <0.05. The EC50 was found to be 166 dilution factor of the effluent. Chlorophyll a, cell density and dry weight production as biomarkers were negatively affected by high indigo dye effluent concentration, their levels were higher at low effluent concentrations (p <0.05. Changes in coenobia size significantly correlated with the dye effluent concentration. A shift from large to small coenobia with increasing indigo dye effluent concentration was obtained. We conclude that even at low concentrations; effluents from textile industrial processes that use indigo dye are capable of significantly reducing the growth and biomass production, in addition to altering the morphological characteristics of the freshwater microalga S. quadricauda. The systematic reduction in the number of cells per coenobium observed in this study further confirms that environmental stress affects coenobium structure in the genus Scenedesmus, which means it can be considered an important biomarker for toxicity testing.

  14. Enhancement of biodiesel production from marine alga, Scenedesmus sp. through in situ transesterification process associated with acidic catalyst.

    Science.gov (United States)

    Kim, Ga Vin; Choi, Woonyong; Kang, Dohyung; Lee, Shinyoung; Lee, Hyeonyong

    2014-01-01

    The aim of this study was to increase the yield of biodiesel produced by Scenedesmus sp. through in situ transesterification by optimizing various process parameters. Based on the orthogonal matrix analysis for the acidic catalyst, the effects of the factors decreased in the order of reaction temperature (47.5%) > solvent quantity (26.7%) > reaction time (17.5%) > catalyst amount (8.3%). Based on a Taguchi analysis, the effects of the factors decreased in the order of solvent ratio (34.36%) > catalyst (28.62%) > time (19.72%) > temperature (17.32%). The overall biodiesel production appeared to be better using NaOH as an alkaline catalyst rather than using H2SO4 in an acidic process, at 55.07 ± 2.18% (based on lipid weight) versus 48.41 ± 0.21%. However, in considering the purified biodiesel, it was found that the acidic catalyst was approximately 2.5 times more efficient than the alkaline catalyst under the following optimal conditions: temperature of 70 °C (level 2), reaction time of 10 hrs (level 2), catalyst amount of 5% (level 3), and biomass to solvent ratio of 1 : 15 (level 2), respectively. These results clearly demonstrated that the acidic solvent, which combined oil extraction with in situ transesterification, was an effective catalyst for the production of high-quantity, high-quality biodiesel from a Scenedesmus sp.

  15. Development of an oven drying protocol to improve biodiesel production for an indigenous chlorophycean microalga Scenedesmus sp.

    Science.gov (United States)

    Bagchi, Sourav Kumar; Rao, Pavuluri Srinivasa; Mallick, Nirupama

    2015-03-01

    Drying of wet algal biomass is a major bottleneck in viable commercial production of the microalgal biodiesel. In the present investigation, an oven drying protocol was standardized for drying of wet Scenedesmus biomass at 60, 80 and 100°C with initial sample thickness of 5.0, 7.5 and 10.0mm. The optimum drying temperature was found to be 80°C with a maximum lipid yield of 425.0±5.9mgg(-1) at 15h drying time for 5.0mm thick samples with 0.033kWh power consumption. Partial drying at 80°C up to 10% residual moisture content was efficient showing 93% lipid recovery with 8h drying and a power consumption of 0.017kWh. Scenedesmus biomass was also found to be rich in saturated and mono-unsaturated fatty acids. Thus, the drying protocol demonstrates its suitability to improve the downstream processing of biodiesel production by significantly lowering the power consumption and the drying time. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Inmovilización de las microalgas Scenedesmus ovalternus (Scenedesmaceae y Chlorella vulgaris (Chlorellaceae en esferas de alginato de calcio.

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    Mario Andres Forero-Cujiño

    2016-05-01

    Full Text Available En este trabajo se describe la técnica de inmovilización de microalgas en esferas de alginato de calcio. Se emplearon las especies Scenedesmus ovalternus y Chlorella vulgaris, se determinó la estabilidad de las esferas, la cinética de crecimiento y la concentración de las microalgas en el interior de las esferas. Chlorella vulgaris alcanzó mayores densidades poblacionales y tasas de crecimiento más altas cuando se inmovilizó en concentraciones del 10 % v/v con el alginato (1,31*106 cél/ml. Para Scenedesmus ovalternus se observó una mayor densidad poblacional y una mayor tasa de crecimiento cuando se inmovilizó en concentraciones del 20 % v/v (7,06*105 cél/ml. Estos resultados son útiles para aplicaciones prácticas de las algas encapsuladas, tales como el biomonitoreo o la biorremediación.

  17. Enhancement of Biodiesel Production from Marine Alga, Scenedesmus sp. through In Situ Transesterification Process Associated with Acidic Catalyst

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    Ga Vin Kim

    2014-01-01

    Full Text Available The aim of this study was to increase the yield of biodiesel produced by Scenedesmus sp. through in situ transesterification by optimizing various process parameters. Based on the orthogonal matrix analysis for the acidic catalyst, the effects of the factors decreased in the order of reaction temperature (47.5% > solvent quantity (26.7% > reaction time (17.5% > catalyst amount (8.3%. Based on a Taguchi analysis, the effects of the factors decreased in the order of solvent ratio (34.36% > catalyst (28.62% > time (19.72% > temperature (17.32%. The overall biodiesel production appeared to be better using NaOH as an alkaline catalyst rather than using H2SO4 in an acidic process, at 55.07 ± 2.18% (based on lipid weight versus 48.41 ± 0.21%. However, in considering the purified biodiesel, it was found that the acidic catalyst was approximately 2.5 times more efficient than the alkaline catalyst under the following optimal conditions: temperature of 70°C (level 2, reaction time of 10 hrs (level 2, catalyst amount of 5% (level 3, and biomass to solvent ratio of 1 : 15 (level 2, respectively. These results clearly demonstrated that the acidic solvent, which combined oil extraction with in situ transesterification, was an effective catalyst for the production of high-quantity, high-quality biodiesel from a Scenedesmus sp.

  18. Enhancement of Biodiesel Production from Marine Alga, Scenedesmus sp. through In Situ Transesterification Process Associated with Acidic Catalyst

    Science.gov (United States)

    Kim, Ga Vin; Choi, WoonYong; Kang, DoHyung; Lee, ShinYoung; Lee, HyeonYong

    2014-01-01

    The aim of this study was to increase the yield of biodiesel produced by Scenedesmus sp. through in situ transesterification by optimizing various process parameters. Based on the orthogonal matrix analysis for the acidic catalyst, the effects of the factors decreased in the order of reaction temperature (47.5%) > solvent quantity (26.7%) > reaction time (17.5%) > catalyst amount (8.3%). Based on a Taguchi analysis, the effects of the factors decreased in the order of solvent ratio (34.36%) > catalyst (28.62%) > time (19.72%) > temperature (17.32%). The overall biodiesel production appeared to be better using NaOH as an alkaline catalyst rather than using H2SO4 in an acidic process, at 55.07 ± 2.18% (based on lipid weight) versus 48.41 ± 0.21%. However, in considering the purified biodiesel, it was found that the acidic catalyst was approximately 2.5 times more efficient than the alkaline catalyst under the following optimal conditions: temperature of 70°C (level 2), reaction time of 10 hrs (level 2), catalyst amount of 5% (level 3), and biomass to solvent ratio of 1 : 15 (level 2), respectively. These results clearly demonstrated that the acidic solvent, which combined oil extraction with in situ transesterification, was an effective catalyst for the production of high-quantity, high-quality biodiesel from a Scenedesmus sp. PMID:24689039

  19. Role of Geitlerinema sp. DE2011 and Scenedesmus sp. DE2009 as Bioindicators and Immobilizers of Chromium in a Contaminated Natural Environment

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    Laia Millach

    2015-01-01

    Full Text Available The aim of this work was to study the potential of the two phototrophic microorganisms, both isolated from Ebro Delta microbial mats, to be used as bioindicators and immobilizers of chromium. The results obtained indicated that (i the Minimum Metal Concentration (MMC significantly affecting Chlorophyll a intensity in Geitlerinema sp. DE2011 and Scenedesmus sp. DE2009 was 0.25 µM and 0.75 µM, respectively, these values being lower than those established by current legislation, and (ii Scenedesmus sp. DE2009 was able to immobilize chromium externally in extracellular polymeric substances (EPS and intracellularly in polyphosphate (PP inclusions. Additionally, this microorganism maintained high viability, including at 500 µM. Based on these results, we postulate that Geitlerinema sp. DE2011 and Scenedesmus sp. DE2009 are good chromium-indicators of cytotoxicity and, further, that Scenedesmus sp. DE2009 plays an important role in immobilizing this metal in a contaminated natural environment.

  20. The effect of ozone on photosynthesis and respiration of Scenedesmus obtusiusculus Chod., with a general discussion of effects of air pollutants in plants

    NARCIS (Netherlands)

    Verkroost, M.

    1974-01-01

    In the present study the mode of action of the air pollutant ozone was investigated by studying its effects on photosynthesis, respiration and some biochemical and structural properties of the unicellular alga, Scenedesmus obtusiusculus CHOD.

    In chapter 1, an

  1. Extraction and anticoagulant activity of sulfated polysaccharides from Caulerpa cupressoides var. lycopodium (Vahl C. Agardh (Chlorophyceae - doi: 10.4025/actascibiolsci.v33i2.6243 Extraction and anticoagulant activity of sulfated polysaccharides from Caulerpa cupressoides var. lycopodium (Vahl C. Agardh (Chlorophyceae - doi: 10.4025/actascibiolsci.v33i2.6243

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    Norma Maria Barros Benevides

    2011-05-01

    Full Text Available The reportedly low standard quality of heparin (HEP for use in cardiac surgeries has led to concern in the Brazilian and international markets. Sulfated polysaccharides (SPs from seaweeds have been regarded as promising substitutes for HEP. The aim of this study was to sequentially extract total SPs (TSPs from Caulerpa cupressoides (Chlorophyceae with papain in 100 mM sodium acetate buffer (pH 5.0 containing 5 mM cysteine and 5 mM EDTA, followed by fractionation by ion-exchange chromatography (DEAE-cellulose, and then evaluate the anticoagulant potential of SP fractions by activated partial thromboplastin time (APTT using normal human plasma and compare it to standard HEP (193 IU mg-1. The obtained fractions were chemically characterized by chemical composition and agarose gel electrophoresis. The yield was 4.61%, and three fractions of SP (F I, F II and F III eluted with 0.50, 0.75 and 1.00 M of NaCl, respectively, were observed on chromatography profiles; however, differences in charge densities patterns and degree of resolution among them were revealed by electrophoresis. SPs were capable of modifying APTT only in fractions eluted with 0.75 M of NaCl, whose activities were 23.37 and 25.76 IU mg-1, respectively, and the charge density was prerequisite to activity. Therefore, C. cupressoides is a source of SPs possessing low anticoagulant potential compared to HEP.The reportedly low standard quality of heparin (HEP for use in cardiac surgeries has led to concern in the Brazilian and international markets. Sulfated polysaccharides (SPs from seaweeds have been regarded as promising substitutes for HEP. The aim of this study was to sequentially extract total SPs (TSPs from Caulerpa cupressoides (Chlorophyceae with papain in 100 mM sodium acetate buffer (pH 5.0 containing 5 mM cysteine and 5 mM EDTA, followed by fractionation by ion-exchange chromatography (DEAE-cellulose, and then evaluate the anticoagulant potential of SP fractions by activated

  2. Responses of photosystems I and II of Acutodesmus obliquus to chemical stress caused by the use of recycled nutrients.

    Science.gov (United States)

    Patzelt, Dominik J; Hindersin, Stefan; Kerner, Martin; Hanelt, Dieter

    2016-01-01

    Nutrients derived from hydrothermal gasification of Acutodesmus obliquus were tested on its biological compatibility to support growth of the same microalgae. Photosynthetic parameters of photosystems I and II (PS I and PS II) were investigated to study physiological effects on the microalgal cell. The nutrients were collected as liquid residues. Dilutions of 1:500 showed no effect on both photosystems. Lower dilutions affected PS II initially and later also PS I. Cyclic electron flow around PS I compensated for loss of electrons due to partially inhibited PS II. The highest tested concentration of liquid residue erased any photosynthetic activity of PS II after 28 min and onwards. In contrast, PS I remained active. The results suggest that PS I is less susceptible than PS II and that the mixture of chemicals in the liquid residue did not directly affect PS I but PS II. The toxicants in the residues seemed to interfere with linear electron flow of PS II even though light-driven formation of radicals and subsequent damage to one of the photosystems can be excluded as demonstrated in darkness. Lowered photosynthetic activity of PS I during actinic irradiation was caused due to lack of supply of electrons from PS II. The cyclic electron flow might play a key role in delivering the energy needed to restore PS II activity and to biodegrade the toxicants when linear electron flow failed. These negative effects of liquid residue towards microalgal cells require a remediation step for direct application of the liquid residue to substitute commercial fertilizers in microalgal mass cultures.

  3. An easy PCR-based genome-walking method for getting the unknown 5’ flanking region of a Scenedesmus sp.

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    Ahmed Elsayed Gomma

    2015-05-01

    Full Text Available Objective: To develop the current single primer PCR-based genome-walking method with Scenedesmus sp. Methods: The unknown 5’ and/or 3’ flanking regions for a specific conserved sequence were optimized and the current single primer PCR-based genome-walking method were developed. Alignment was between the related species of microalga and Scenedesmus sp. For 18S rDNA, we selected the species Scenedesmus sp., Chlorella sp., and Chlamydomonas sp. For the rbcL gene from the chloroplast genome, alignment was done between Scenedesmus sp., and Chlamydomonas sp. Results: Obtaining a small conserved sequence for any gene family is something that can be achieved quite easily. However, identifying the whole gene is often difficult. After investigating and testing, some of the current protocols using to get the unknown 5’ and/or 3’ flanking regions for a specific conserved sequence, we developed the current single primer PCR-based genome-walking method. We performed two consecutive PCR reactions; band extraction and the PCR product were sequenced. We got our results by testing the method on three genes from the total DNA of Scenedesmus sp.; two genes had a fully known sequence in gene bank (18S rDNA and rbcL, but the third one has not yet been identified (rbcS. We designed our primers based on the alignment between the related species and to each other. We also tested two different DNA polymerases Ex Taq and TLA polymerase. Conclusions: Results from our study suggest that Ex Taq is the most suitable polymerase for the current protocol.

  4. Model-supported phototrophic growth studies with Scenedesmus obtusiusculus in a flat-plate photobioreactor.

    Science.gov (United States)

    Koller, Anja Pia; Löwe, Hannes; Schmid, Verena; Mundt, Sabine; Weuster-Botz, Dirk

    2017-02-01

    Light-dependent growth of microalgae can vary remarkably depending on the cultivation system and microalgal strain. Cell size and the pigmentation of each strain, as well as reactor geometry have a great impact on absorption and scattering behavior within a photobioreactor. In this study, the light-dependent, cell-specific growth kinetics of a novel green algae isolate, Scenedesmus obtusiusculus, was studied in a LED-illuminated flat-plate photobioreactor on a lab-scale (1.8 L, 0.09 m2 ). First, pH-controlled batch processes were performed with S. obtusiusculus at different constant incident photon flux densities. The best performance was achieved by illuminating S. obtusiusculus with 1400 μmol photons m-2  s-1 at the surface of the flat-plate photobioreactor, resulting in the highest biomass concentration (4.95 ± 0.16 gCDW  L-1 within 3.5 d) and the highest specific growth rate (0.22 h-1 ). The experimental data were used to identify the kinetic parameters of different growth models considering light inhibition for S. obtusiusculus. Light attenuation within the flat-plate photobioreactor was considered by varying light transfer models. Based on the identified kinetic growth model of S. obtusiusculus, an optimum growth rate of 0.22 h-1 was estimated at a mean integral photon flux density of 1072 μmol photons m-2  s-1 with the Beer-Lambert law and 1590 μmol photons m-2  s-1 with Schuster's light transfer model in the flat-plate photobioreactor. LED illumination was, thus, increased to keep the identified optimum mean integral photon flux density constant in the batch process assuming Schuster's light transfer model. Compared to the same constant incident photon flux density (1590 μmol photons m-2  s-1 ), biomass concentration was up to 24% higher using the lighting profile until a dry cell mass concentration of 14.4 ± 1.4 gCDW  L-1 was reached. Afterward, the biomass concentration remained constant, whereas cell growth

  5. Anti-diabetic effects of Inonotus obliquus polysaccharides-chromium (III) complex in type 2 diabetic mice and its sub-acute toxicity evaluation in normal mice.

    Science.gov (United States)

    Wang, Cong; Chen, Zhongqin; Pan, Yuxiang; Gao, Xudong; Chen, Haixia

    2017-10-01

    Polysaccharides are important bioactive ingredients from Inonotus obliquus. This study aimed to synthesize and characterize a novel I. obliquus polysaccharides-chromium (III) complex (UIOPC) and investigate the anti-diabetic effects in streptozotocin (STZ) induced type 2 diabetes mellitus (T2DM) mice and sub-acute toxicity in normal mice. The molecular weight of UIOPC was about 11.5 × 10 4 Da with the chromium content was 13.01% and the chromium was linked with polysaccharides through coordination bond. After treatment of UIOPC for four weeks, the body weight, fasting blood glucose (FBG) levels, plasma insulin levels of the diabetic mice were significantly reduced when compared with those of the diabetic mice (p < 0.05). The results on serum profiles and antioxidant enzymes activities revealed that UIOPC had a positive effect on hypoglycemic and antioxidant ability. Histopathology results showed that UIOPC could effectively alleviate the STZ-lesioned tissues in diabetic mice. Furthermore, high dose administration of UIOPC had no obviously influence on serum profiles levels and antioxidant ability of the normal mice and the organ tissues maintained organized and integrity in the sub-acute toxicity study. These results suggested that UIOPC might be a good candidate for the functional food or pharmaceuticals in the treatment of T2DM. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Preparation of Chaga medicinal mushroom, Inonotus obliquus-fermented rice using solid-state fermentation and its taste quality and antioxidant property.

    Science.gov (United States)

    Lin, Shin-Yi; Yeh, Chan-Chun; Liang, Chih-Hung; Mau, Jeng-Leun

    2012-01-01

    Chaga medicinal mushroom, Inonotus obliquus (Pers.:Fr.) Pilat, was inoculated into cooked embryo rice and the mycelial growth in I. obliquus-fermented embryo rice (IER) was monitored. Besides, nonvolatile taste components and antioxidant properties of fruiting bodies, mycelia, IER, and embryo rice were studied. The optimal conditions for mycelial growth were determined to be: 30°C, an inoculation rate of 1 mL/15 g, water supplementation of 60%, and no extra nitrogen source added. IER showed similar proximate composition to embryo rice but contained a substantial amount of ergothioneine (101 mg/kg dry weight). IER contained higher amounts of soluble sugars and polyols, and umami taste components, including monosodium glutamate (MSG)-like components and flavor 5'-nucleotides, than embryo rice. Besides, IER showed a second level of equivalent umami concentrations (223.73 g MSG/100 g). Fruiting bodies did not contain umami components but showed the most effective antioxidant properties. Although some of EC50 values of IER were less than those of mycelia and embryo rice, IER still showed effective antioxidant properties. Based on the results obtained, IER will be a novel functional food.

  7. Nitrogen recycling from fuel-extracted algal biomass: residuals as the sole nitrogen source for culturing Scenedesmus acutus.

    Science.gov (United States)

    Gu, Huiya; Nagle, Nick; Pienkos, Philip T; Posewitz, Matthew C

    2015-05-01

    In this study, the reuse of nitrogen from fuel-extracted algal residues was investigated. The alga Scenedesmus acutus was found to be able to assimilate nitrogen contained in amino acids, yeast extracts, and proteinaceous alga residuals. Moreover, these alternative nitrogen resources could replace nitrate in culturing media. The ability of S. acutus to utilize the nitrogen remaining in processed algal biomass was unique among the promising biofuel strains tested. This alga was leveraged in a recycling approach where nitrogen is recovered from algal biomass residuals that remain after lipids are extracted and carbohydrates are fermented to ethanol. The protein-rich residuals not only provided an effective nitrogen resource, but also contributed to a carbon "heterotrophic boost" in subsequent culturing, improving overall biomass and lipid yields relative to the control medium with only nitrate. Prior treatment of the algal residues with Diaion HP20 resin was required to remove compounds inhibitory to algal growth. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Growth and biomass productivity of Scenedesmus vacuolatus on a twin layer system and a comparison with other types of cultivations.

    Science.gov (United States)

    Carbone, Dora Allegra; Olivieri, Giuseppe; Pollio, Antonino; Gabriele; Melkonian, Michael

    2017-12-01

    Scenedesmus is a genus of microalgae employed for several industrial uses. Industrial cultivations are performed in open ponds or in closed photobioreactors (PBRs). In the last years, a novel type of PBR based on immobilized microalgae has been developed termed porous substrate photobioreactors (PSBR) to achieve significant higher biomass density during cultivation in comparison to classical PBRs. This work presents a study of the growth of Scenedesmus vacuolatus in a Twin Layer System PSBR at different light intensities (600 μmol photons m-2 s-1 or 1000 μmol photons m-2 s-1), different types and concentrations of the nitrogen sources (nitrate or urea), and at two CO2 levels in the gas phase (2% or 0.04% v/v). The microalgal growth was followed by monitoring the attached biomass density as dry weight, the specific growth rate and pigment accumulation. The highest productivity (29 g m-2 d-1) was observed at a light intensity of 600 μmol photons m-2 s-1 and 2% CO2. The types and concentrations of nitrogen sources did not influence the biomass productivity. Instead, the higher light intensity of 1000 μmol photons m-2 s-1 and an ambient CO2 concentration (0.04%) resulted in a significant decrease of productivity to 18 and 10-12 g m-2 d-1, respectively. When compared to the performance of similar cultivation systems (15-30 g m-2 d-1), these results indicate that the Twin Layer cultivation System is a competitive technique for intensified microalgal cultivation in terms of productivity and, at the same time, biomass density.

  9. Wpływ niektórych detergentów na przyrost biomasy Solanum lycopersicum i Scenedesmus quadricauda oraz na akumulację składników mineralnych u tych roślin [The effect of some detergents on the increase in biomass and the accumulation of mineral components in Solanum lycopersicum and Scenedesmus quadricauda

    Directory of Open Access Journals (Sweden)

    St. Gumiński

    2015-01-01

    Full Text Available The investigation on water cultures of tomato seedlings and Scenedesmus quadricauda colonies have shown that low doses of the detergents stimulate the growth of these plants. An intensified accumulation of N, P, Ca, Mg, Fe and a reduced accumulation of K-ions have been observed.

  10. Quantum chemistry based quantitative structure-activity relationships for modeling the (sub)acute toxicity of substituted mononitrobenzenes in aquatic systems

    NARCIS (Netherlands)

    Zvinavashe, E.; Murk, A.J.; Vervoort, J.; Soffers, A.E.M.F.; Freidig, A.; Rietjens, I.M.C.M.

    2006-01-01

    Fifteen experimental literature data sets on the acute toxicity of substituted nitrobenzenes to algae (Scenedesmus obliquus, Chlorella pyrenoidosa, C. vulgaris), daphnids (Daphnia magna, D. carinata), fish (Cyprinus carpio, Poecilia reticulata), protozoa (Tetrahymena pyriformis), bacteria

  11. Beating the blues: Is there any music in fighting cyanobacteria with ultrasound?

    NARCIS (Netherlands)

    Lurling, Miquel; Tolman, Yora

    2014-01-01

    The hypothesis that cyanobacteria can be controlled by commercially available ultrasound transducers was tested in laboratory experiments with cultures of the cyanobacteria Anabaena sp., Cylindrospermopsis raciborskii and Microcystis aeruginosa and the green alga Scenedesmus obliquus that were grown

  12. Effect of Temperature and Nutrient Limitation on the Growth and Lipid Content of Three Selected Microalgae (Dunaliella tertiolecta, Nannochloropsis sp. and Scenedesmus sp.) for Biodiesel Production

    OpenAIRE

    Nita Rukminasari

    2013-01-01

    Microalgae is one of potential source for biodiesel due to high efficiency of solar energy conversion to chemical energy. Several microalgae also have high lipid content per dry weight of biomass. The aims of the present work to study the effects of temperature and nutrient depletion on the growth and lipid content of three selected microalgae (Dunaliella tertiolecta, Nannochloropsis sp. and Scenedesmus sp.) in view of their possible utilization as raw materials for biodiesel production. In ...

  13. [A study of the antiherpetic activity of the chaga mushroom (Inonotus obliquus) extracts in the Vero cells infected with the herpes simplex virus].

    Science.gov (United States)

    Polkovnikova, M V; Nosik, N N; Garaev, T M; Kondrashina, N G; Finogenova, M P; Shibnev, V A

    2014-01-01

    The chaga mushroom (Inonotus obliquus) contains a wide range of excellent bioactive compounds. However, limited information exists on the antiviral activity of the compounds extracted from chaga. A number of subfractions of chaga were obtained using different solvents and different procedures. The subfractions of chaga extracted with water, alcohol, alkali were tested for their toxicity for the Vero cell culture and antiviral effect in the Vero cells infected with the Herpes simplex virus (HSV), Type 1. It was shown that most of the subfractions were not toxic for the Vero cells and had protective effect on the Vero cells infected with HSV. The subfraction IV in the concentration 5 microg/ml protected the Vero cells from cytodestructive action of HSV and no viral DNA was detected in infected cells treated with chaga extracts. Best protective effect was observed when compound was added before or within one hour after the Vero cells were infected with HSV.

  14. Nutritional status response of Daphania laevis and Moina micura from a tropical reservoir to different algal diets: Scenedesmus quadricauda and Ankistrodesmus gracilis

    Directory of Open Access Journals (Sweden)

    MACEDO C. F.

    2001-01-01

    Full Text Available The accumulation of lipid reserves was investigated in two common cladoceran species typical of neotropical freshwaters. Experiments were performed in order to measure differential accumulation of lipid reserves in response to two algal diets, S. quadricauda and A. gracilis. The larger D. laevis fed with the Ankistrodesmus diet accumulated a higher amount of total lipids. The average lipid content for both diets was 11.1% and 22.1% dry weight for Scenedesmus and Ankistrodemsus, respectively. This difference was found to be highly significant. The superior nutritional quality of A. gracilis was confirmed by the experiments using the smaller Moina micrura. This cladoceran accumulated 11.4% and 19.9% of the average dry weight of lipids from Scenedesmus and Ankistrodesmus, respectively. The study also found that most lipid reserves are concentrated as triacylglycerols in both cladocerans. The relative contribution of this class of lipids also varied according to the diet. For Daphnia, for instance, the average triacylglycerol levels varied from 6.2 to 11.0 with the Scenedesmus and Ankistrodesmus diets, respectively.

  15. The influence of ultrasound frequency and power, on the algal species Microcystis aeruginosa, Aphanizomenon flos-aquae, Scenedesmus subspicatus and Melosira sp.

    Science.gov (United States)

    Purcell, Diane; Parsons, Simon A; Jefferson, Bruce

    2013-01-01

    We report on the effectiveness of sonication on controlling the growth of four problematic algal species which are morphologically different and from three algal divisions. Two cyanobacterial species Microcystis aeruginosa (unicellular) and Aphanizomenon flos-aquae (filamentous), one green alga Scenedesmus subspicatus (colonial) and lastly a diatom species Melosira sp. (filamentous) were subjected to ultrasound of selected low to high frequencies ranging from 20 to 1144 kHz. Microcystis aeruginosa and Scenedesmus subspicatus highest cell removal rates were 16 +/- 2% and 20 +/- 3% when treated with the same ultrasound frequency of 862 kHz but differing energy levels of 133 and 67 kWh m(-3), respectively. Aphanizomenon flos-aquae best removal rate was 99 +/- 1% after 862 kHz and 133 kWh m(-3) of energy, with Melosira sp. achieving its highest cell removal at 83% subsequent to ultrasound of 20 kHz and 19 kWh m(-3). Microcystis aeruginosa and Scenedesmus subspicatus are considered non-susceptible species to ultrasound treatment from a water treatment perspective due to their low cell removal rates; however, photosynthetic activity reduction of 65% for Microcystis aeruginosa does indicate the possible utilization of ultrasound to control bloom growth, rather than bloom elimination. Conversely, Aphanizomenon flos-aquae and Melosira sp. are deemed species highly susceptible to ultrasound. Morphological differences in shape (filamentous/non-filamentous) and cell wall structure (silica/peptidoglycan), and presence of gas vacuoles are probable reasons for these differing levels of susceptibility to ultrasound.

  16. Vernalophrys algivore gen. nov., sp. nov. (Rhizaria: Cercozoa: Vampyrellida), a New Algal Predator Isolated from Outdoor Mass Culture of Scenedesmus dimorphus.

    Science.gov (United States)

    Gong, Yingchun; Patterson, David J; Li, Yunguang; Hu, Zixuan; Sommerfeld, Milton; Chen, Yongsheng; Hu, Qiang

    2015-06-15

    Microbial contamination is the main cause of loss of biomass yield in microalgal cultures, especially under outdoor environmental conditions. Little is known about the identities of microbial contaminants in outdoor mass algal cultures. In this study, a new genus and species of vampyrellid amoeba, Vernalophrys algivore, is described from cultures of Scenedesmus dimorphus in open raceway ponds and outdoor flat-panel photobioreactors. This vampyrellid amoeba was a significant grazer of Scenedesmus and was frequently associated with a very rapid decline in algal numbers. We report on the morphology, subcellular structure, feeding behavior, molecular phylogeny, and life cycle. The new amoeba resembles Leptophrys in the shape of trophozoites and pseudopodia and in the mechanism of feeding (mainly by engulfment). It possesses two distinctive regions in helix E10_1 (nucleotides 117 to 119, CAA) and E23_1 (nucleotides 522 and 523, AG) of the 18S rRNA gene. It did not form a monophyletic group with Leptophrys in molecular phylogenetic trees. We establish a new genus, Vernalophrys, with the type species Vernalophrys algivore. The occurrence, impact of the amoeba on mass culture of S. dimorphus, and means to reduce vampyrellid amoeba contamination in Scenedesmus cultures are addressed. The information obtained from this study will be useful for developing an early warning system and control measures for preventing or treating this contaminant in microalgal mass cultures. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  17. Nutritional status response of Daphania laevis and Moina micura from a tropical reservoir to different algal diets: Scenedesmus quadricauda and Ankistrodesmus gracilis

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    C. F. MACEDO

    Full Text Available The accumulation of lipid reserves was investigated in two common cladoceran species typical of neotropical freshwaters. Experiments were performed in order to measure differential accumulation of lipid reserves in response to two algal diets, S. quadricauda and A. gracilis. The larger D. laevis fed with the Ankistrodesmus diet accumulated a higher amount of total lipids. The average lipid content for both diets was 11.1% and 22.1% dry weight for Scenedesmus and Ankistrodemsus, respectively. This difference was found to be highly significant. The superior nutritional quality of A. gracilis was confirmed by the experiments using the smaller Moina micrura. This cladoceran accumulated 11.4% and 19.9% of the average dry weight of lipids from Scenedesmus and Ankistrodesmus, respectively. The study also found that most lipid reserves are concentrated as triacylglycerols in both cladocerans. The relative contribution of this class of lipids also varied according to the diet. For Daphnia, for instance, the average triacylglycerol levels varied from 6.2 to 11.0 with the Scenedesmus and Ankistrodesmus diets, respectively.

  18. Selective fermentation of carbohydrate and protein fractions of Scenedesmus, and biohydrogenation of its lipid fraction for enhanced recovery of saturated fatty acids.

    Science.gov (United States)

    Lai, YenJung Sean; Parameswaran, Prathap; Li, Ang; Aguinaga, Alyssa; Rittmann, Bruce E

    2016-02-01

    Biofuels derived from microalgae have promise as carbon-neutral replacements for petroleum. However, difficulty extracting microalgae-derived lipids and the co-extraction of non-lipid components add major costs that detract from the benefits of microalgae-based biofuel. Selective fermentation could alleviate these problems by managing microbial degradation so that carbohydrates and proteins are hydrolyzed and fermented, but lipids remain intact. We evaluated selective fermentation of Scenedesmus biomass in batch experiments buffered at pH 5.5, 7, or 9. Carbohydrates were fermented up to 45% within the first 6 days, protein fermentation followed after about 20 days, and lipids (measured as fatty acid methyl esters, FAME) were conserved. Fermentation of the non-lipid components generated volatile fatty acids, with acetate, butyrate, and propionate being the dominant products. Selective fermentation of Scenedesmus biomass increased the amount of extractable FAME and the ratio of FAME to crude lipids. It also led to biohydrogenation of unsaturated FAME to more desirable saturated FAME (especially to C16:0 and C18:0), and the degree of saturation was inversely related to the accumulation of hydrogen gas after fermentation. Moreover, the microbial communities after selective fermentation were enriched in bacteria from families known to perform biohydrogenation, i.e., Porphyromonadaceae and Ruminococcaceae. Thus, this study provides proof-of-concept that selective fermentation can improve the quantity and quality of lipids that can be extracted from Scenedesmus. © 2015 Wiley Periodicals, Inc.

  19. Demography of zooplankton (Anuraeopsis fissa, Brachionus rubens and Moina macrocopa fed Chlorella vulgaris and Scenedesmus acutus cultured on different media

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    Jesús Morales-Ventura

    2012-09-01

    Full Text Available Generally zooplankton growth is often limited by the quality of their algal diet. A cheaper common practice in aquaculture, is to culture algae with fertilizers; however, the demography of zooplankton when fed these algae has not yet been evaluated. We studied the population growth and life table demography of the rotifers Anuraeopsis fissa and Brachionus rubens, and the cladoceran Moina macrocopa. For this, the algae Scenedesmus acutus or Chlorella vulgaris were cultured on defined (Bold’s basal medium or the commercial liquid fertilizer (Bayfolan. Experiments were conducted at one algal concentration 1.0x10(6cells/mL of C. vulgaris or its equivalent dry weight of 0.5x10(6cells/mL of S. acutus. The population dynamics were tested at 23±1ºC in 100mL transparent jars, each with 50mL of the test medium, with an initial density of 0.5indiv/mL, for a total of 48 test jars (3 zooplankton 2 algal species x 2 culture media x 4 replicates. For the life table experiments with M. macrocopa, we introduced 10 neonates (Generalmente el crecimiento del zooplancton está a menudo limitado por la calidad de su dieta de algas. La demografía del zooplancton durante la alimentación con algas no ha sido estudiada, a pesar de que el cultivo de algas con fertilizantes es una práctica económica común en acuacultura. Se analizó la demografía de Anuraeopsis fissa y Brachionus rubens (rotíferos y Moina macrocopa (cladóceros, alimentados con las algas verdes Scenedesmus acutus o Chlorella vulgaris cultivadas en medio Bold o fertilizante líquido comercial (Bayfolan, de Bayer. En los rotíferos no se observaron diferencias significativas en el promedio de vida, sin embargo, este parámetro en M. macrocopa con S. acutus cultivada en Medio Bold, fue significativamente menor que en otras dietas. Las tasas de reproducción bruta y neta de A. fissa fueron significativamente mayores con C. vulgaris cultivada en medio Bold, que con el fertilizante; estas tasas en B

  20. Efeito caotrópico do íon lítio na permeabilidade da cápsula polissacarídica da microalga Ankistrodesmus gracilis (Reinsch Korsikov (Chlorophyceae Chaotropic effect of lithium íon on permeability of polysaccharide capsule of the microalga Ankistrodesmus gracilis (Reinsch Korsikov (Chlorophyceae

    Directory of Open Access Journals (Sweden)

    Cristina Souza Freire Nordi

    2006-06-01

    Full Text Available O objetivo deste trabalho foi investigar o efeito caotrópico do íon Li+ na cápsula polissacarídica da microalga colonial Ankistrodesmus gracilis. Esta microalga possui uma cápsula extensa e contínua que envolve completamente as células. Neste estudo, foram utilizados a técnica de Ressonância Paramagnética Eletrônica (RPE e o marcador de spin - Tempo (2,2,6,6-tetrametilpiperidine-1-oxil, de natureza não reativa. A técnica de RPE é utilizada para monitorar o tempo de difusão dos marcadores de spin através da cápsula polissacarídica, parede e membrana celular, até o interior da célula, onde eles perdem suas propriedades paramagnéticas. O íon Li+ utilizado tem a propriedade de provocar a desorganização estrutural da cápsula e, em conseqüência, a modificação do tempo de difusão do marcador de spin. Observou-se que os tempos de decaimento do sinal paramagnético nas células tratadas com Li+ são sempre menores do que nas células não expostas ao Li+ e que os tempos de difusão diminuem com o aumento da concentração de LiCl . As fotomicrografias das algas mostram que a partir da concentração de LiCl 1,0 M, as cápsulas são totalmente retiradas, resultando em células que se aglutinam formando grumos. Também foi constatada a morte das células acima quando expostas a concentração de LiCl acima de 1,0 M.The aim of this study was to investigate the role of chaotropic effect of Li+ on the polysaccharide sheath of the microalga Ankistrodesmus gracilis (Chlorophyceae, Chlorococales in the selective permeability and transport of molecules in the interior of the cell. The colonial microalga Ankistrodesmus gracilis has a relatively large and continuous mucilaginous sheath. The Electron Paramagnetic Resonance (EPR was applied using the spin label- Tempo 2,2,6,6-tetramethylpiperidine-1-oxyl of non-reactive nature to study its diffusion coefficients across the polysaccharide envelope. The EPR technique is used to monitor the

  1. Removal of Nitrate and Phosphate from Municipal Wastewater Sludge by Chlorella vulgaris, Spirulina platensis and Scenedesmus quadricauda

    Directory of Open Access Journals (Sweden)

    Jalal K.C.A

    2011-12-01

    Full Text Available Nitrate and phosphorus in wastewater contribute to health and environmental threats as they are linked to illnesses as well as ecosystem disruption via algal blooms in contaminated water bodies. Based on above perspectives a comparative study was conducted on three local freshwater microalgae:Chlorella vulgaris, Spirulina platensis and Scenedesmus quadricauda to evaluate their effects on nitrate and phosphorus removal from municipal wastewater sludge (MWS. Algae performance in removing nitrate and phosphorus was evaluated by measuring nitrate and phosphorus content of MWS incubated with the strains for 7 days. Instantaneous readings were taken every 48 hours to determine periodic levels of the nutrients phosphate and nitrate. BOD5 was also evaluated to identify the strain with the most robust growth that would demand for oxygen the most in the dark. Spirulina platensis was shown as the most efficient microalgae to reduce nitrate in MWS and the best-growing among the three strains, while Chlorella vulgaris removed phosphorus the most effectively. Thus Spirulina and Chlorella could be potential candidates by showing their intrinsic merit for the reduction of phosphate and nitrate in wastewater treatment.ABSTRAK: Nitrat dan fosforus dalam air sisa menggugat kesihatan dan mengancam alam sekitar memandangkan ia berkait dengan penyakit-penyakit serta gangguan terhadap ekosistem melalui pembiakan alga dalam air yang tercemar. Berdasarkan perspektif di atas, satu kajian perbandingan telah dijalankan terhadap tiga mikro alga air tawar tempatan : Chlorella vulgaris, Spirulina platensis dan Scenedesmus quadricauda untuk dinilai kesannya terhadap penyingkiran nitrat dan fosforus dari enap cemar air sisa bandaran (municipal wastewater sludge (MWS. Kebolehan alga dalam penyingkiran nitrat dan fosforus dikaji dengan menyukat kandungan nitrat dan fosforus dalam MWS yang dieramkan dengan strain ini selama 7 hari. Bacaan serta-merta diambil setiap 48 jam untuk

  2. Demography of zooplankton (Anuraeopsis fissa, Brachionus rubens and Moina macrocopa) fed Chlorella vulgaris and Scenedesmus acutus cultured on different media.

    Science.gov (United States)

    Morales-Ventura, Jesús; Nandini, S; Sarma, S S S; Castellanos-Páez, Maria Elena

    2012-09-01

    Generally zooplankton growth is often limited by the quality of their algal diet. A cheaper common practice in aquaculture, is to culture algae with fertilizers; however, the demography of zooplankton when fed these algae has not yet been evaluated. We studied the population growth and life table demography of the rotifers Anuraeopsis fissa and Brachionus rubens, and the cladoceran Moina macrocopa. For this, the algae Scenedesmus acutus or Chlorella vulgaris were cultured on defined (Bold's basal) medium or the commercial liquid fertilizer (Bayfolan). Experiments were conducted at one algal concentration 1.0 x 10(6) cells/mL of C. vulgaris or its equivalent dry weight of 0.5 x 10(6) cells/mL of S. acutus. The population dynamics were tested at 23 +/- 1 degrees C in 100 mL transparent jars, each with 50mL of the test medium, with an initial density of 0.5indiv/mL, for a total of 48 test jars (3 zooplankton 2 algal species x 2 culture media x 4 replicates). For the life table experiments with M. macrocopa, we introduced 10 neonates (vulgaris cultured in Bold medium. Regardless of the culture medium, Chlorella resulted in significantly higher gross and net reproductive rates for B. rubens than S. acutus diets. The reproductive rates of M. macrocopa were significantly higher in all the tested diets except when fed with S. acutus in Bold medium. The population increase rate, derived from growth experiments of A. fissa and B. rubens, ranged from 0.1-0.25/d and were significantly higher on C vulgaris cultured in liquid fertilizer as compared to the other diets. The growth rates of M. macrocopa ranged from 0.1 to 0.38/d, and were highest with diets of C. vulgaris cultured in Bold medium and S. acutus cultured in fertilizer. Thus, regardless of the culture medium used, the growth rates of the evaluated zooplankton species were higher with Chlorella than with Scenedesmus. The peak population density was highest (2 800ind/mL) for A. fissa fed Chlorella that was cultured on

  3. Toxic effects of some major polyaromatic hydrocarbons found in crude oil and aquatic sediments on Scenedesmus subspicatus

    Energy Technology Data Exchange (ETDEWEB)

    Djomo, J.E. [Universite de Dschang Cameroun, Toulouse (France). Laboratoire de Biologie Animale; Dauta, A. [Universite Paul Sabatier, Toulouse (France). CESAC; Ferrier, V. [UMR-CNRS 9925 affiliee a l' INSERM, Toulouse (France); Narbonne, J.F. [Universite de Bordeaux I, Talence (France). Laboratoire de Toxicologie Alimentaire; Monkiedje, A.; Njine, T. [Universite de Yaounde 1, Cameroun, Toulouse (France). Laboratoire de Biologie et Physiologie Animales; Garrigues, P. [Universite de Bordeaux I, Talence (France). UPRES A 5472 CNRS

    2004-04-01

    The green alga, Scenedesmus subspicatus was exposed for 7 days to a series of PAHs (polyaromatic hydrocarbons) of increased molecular weight from two to five rings [naphthalene (Nap), anthracene (Ant), phenanthrene (Phe), pyrene (Pyr) and benzo(a)pyrene (BaP)]. The toxicity measured as population growth inhibition by individual PAH to the S. subspicatus followed the order: BaP>Pyr>Ant>Phe>Nap. These results confirmed that the toxicity potential of PAHs seems to be strongly influenced by their physico-chemical properties (aqueous solubility, K{sub ow}, coefficient of volatilization, etc.) and the conditions of algae culture (light, presence of nitrate ions, etc.). Consequently, Nap, Phe and Ant having low K{sub ow} values and low coefficient of volatilization values were less toxic than BaP with the highest k{sub ow} value, indicating for example why Nap with the lowest EC{sub 50} value was nearly 2x10{sup 5} times lower than that of BaP. Moreover, nitrate ions seemed to act directly on the degree of hydroxylated radical reactivity of PAHs, since BaP always remained the most toxic of the compounds tested. The results were also agreed with the QSAR model for toxicity prediction of PAHs to many aquatic organisms. (author)

  4. Biosorption of Strontium from Simulated Nuclear Wastewater by Scenedesmus spinosus under Culture Conditions: Adsorption and Bioaccumulation Processes and Models

    Science.gov (United States)

    Liu, Mingxue; Dong, Faqin; Kang, Wu; Sun, Shiyong; Wei, Hongfu; Zhang, Wei; Nie, Xiaoqin; Guo, Yuting; Huang, Ting; Liu, Yuanyuan

    2014-01-01

    Algae biosorption is an ideal wastewater treatment method when coupled with algae growth and biosorption. The adsorption and bioaccumulation of strontium from simulated nuclear wastewater by Scenedesmus spinosus were investigated in this research. One hundred mL of cultured S. spinosus cells with a dry weight of 1.0 mg in simulated nuclear wastewater were used to analyze the effects on S. spinosus cell growth as well as the adsorption and bioaccumulation characters under conditions of 25 ± 1 °C with approximately 3,000 lux illumination. The results showed that S. spinosus had a highly selective biosorption capacity for strontium, with a maximum bioremoval ratio of 76%. The adsorbed strontium ion on cell walls was approximately 90% of the total adsorbed amount; the bioaccumulation in the cytoplasm varied by approximately10%. The adsorption quantity could be described with an equilibrium isotherm. The pseudo-second-order kinetic model suggested that adsorption was the rate-limiting step of the biosorption process. A new bioaccumulation model with three parameters was proposed and could give a good fit with the experiment data. The results suggested that S. spinosus may be a potential biosorbent for the treatment of nuclear wastewater in culture conditions. PMID:24919131

  5. Influence of abscisic acid on growth, biomass and lipid yield of Scenedesmus quadricauda under nitrogen starved condition.

    Science.gov (United States)

    Sulochana, Sujitha Balakrishnan; Arumugam, Muthu

    2016-08-01

    Scenedesmus quadricauda, accumulated more lipid but with a drastic reduction in biomass yield during nitrogen starvation. Abscisic acid (ABA) being a stress responsible hormone, its effect on growth and biomass with sustainable lipid yield during nitrogen depletion was studied. The result revealed that the ABA level shoots up at 24h (27.21pmol/L) during the onset of nitrogen starvation followed by a sharp decline. The external supplemented ABA showed a positive effect on growth pattern (38×10(6)cells/ml) at a lower concentration. The dry biomass yield is also increasing up to 2.1 fold compared to nitrogen deficient S. quadricauda. The lipid content sustains in 1 and 2μM concentration of ABA under nitrogen-deficient condition. The fatty acid composition of ABA treated S. quadricauda cultures with respect to nitrogen-starved cells showed 11.17% increment in saturated fatty acid content, the desired lipid composition for biofuel application. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Acidogenic fermentation of Scenedesmus sp.-AMDD: Comparison of volatile fatty acids yields between mesophilic and thermophilic conditions.

    Science.gov (United States)

    Gruhn, Marvin; Frigon, Jean-Claude; Guiot, Serge R

    2016-01-01

    This study compared the acidogenic fermentation of Scenedesmus sp.-AMDD at laboratory-scale, under mesophilic (35°C) and thermophilic conditions (55°C). Preliminary batch tests were performed to evaluate best conditions for volatile fatty acid (VFA) production from microalgal biomass, with respect to the inoculum, pH and nutrients. The use of bovine manure as inoculum, the operating pH of 4.5 and the addition of a nutrient mix, resulted in a high VFA production of up to 222mgg(-1) total volatile solid (TVS), with a butyrate share of 27%. Both digesters displayed similar hydrolytic activity with 0.38±0.02 and 0.42±0.03 g soluble chemical oxygen demand (COD)g(-1) TVS for the digesters operated at 35 and 55°C, respectively. Mesophilic conditions were more favorable for VFA production, which reached 171±5, compared to 88±12 mg soluble CODg(-1) TVS added under thermophilic conditions (94% more). It was shown that in both digesters, butyrate was the predominant VFA. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  7. Biosorption of Strontium from Simulated Nuclear Wastewater by Scenedesmus spinosus under Culture Conditions: Adsorption and Bioaccumulation Processes and Models

    Directory of Open Access Journals (Sweden)

    Mingxue Liu

    2014-06-01

    Full Text Available Algae biosorption is an ideal wastewater treatment method when coupled with algae growth and biosorption. The adsorption and bioaccumulation of strontium from simulated nuclear wastewater by Scenedesmus spinosus were investigated in this research. One hundred mL of cultured S. spinosus cells with a dry weight of 1.0 mg in simulated nuclear wastewater were used to analyze the effects on S. spinosus cell growth as well as the adsorption and bioaccumulation characters under conditions of 25 ± 1 °C with approximately 3,000 lux illumination. The results showed that S. spinosus had a highly selective biosorption capacity for strontium, with a maximum bioremoval ratio of 76%. The adsorbed strontium ion on cell walls was approximately 90% of the total adsorbed amount; the bioaccumulation in the cytoplasm varied by approximately10%. The adsorption quantity could be described with an equilibrium isotherm. The pseudo-second-order kinetic model suggested that adsorption was the rate-limiting step of the biosorption process. A new bioaccumulation model with three parameters was proposed and could give a good fit with the experiment data. The results suggested that S. spinosus may be a potential biosorbent for the treatment of nuclear wastewater in culture conditions.

  8. Effect of CO2 Concentration on Growth and Biochemical Composition of Newly Isolated Indigenous Microalga Scenedesmus bajacalifornicus BBKLP-07.

    Science.gov (United States)

    Patil, Lakkanagouda; Kaliwal, Basappa

    2017-05-01

    Photosynthetic mitigation of CO2 through microalgae is gaining great importance due to its higher photosynthetic ability compared to plants, and the biomass can be commercially exploited for various applications. CO2 fixation capability of the newly isolated freshwater microalgae Scenedesmus bajacalifornicus BBKLP-07 was investigated using a 1-l photobioreactor. The cultivation was carried at varying concentration of CO2 ranging from 5 to 25%, and the temperature and light intensities were kept constant. A maximum CO2 fixation rate was observed at 15% CO2 concentration. Characteristic growth parameters such as biomass productivity, specific growth rate, and maximum biomass yield, and biochemical parameters such as carbohydrate, protein, lipid, chlorophyll, and carotenoid were determined and discussed. It was observed that the effect of CO2 concentration on growth and biochemical composition was quite significant. The maximum biomass productivity was 0.061 ± 0.0007 g/l/day, and the rate of CO2 fixation was 0.12 ± 0.002 g/l/day at 15% CO2 concentration. The carbohydrate and lipid content were maximum at 25% CO2 with 26.19 and 25.81% dry cell weight whereas protein, chlorophyll, and carotenoid contents were 32.89% dry cell weight, 25.07 μg/ml and 6.15 μg/ml respectively at 15% CO2 concentration.

  9. DNA Damage during G2 Phase Does Not Affect Cell Cycle Progression of the Green Alga Scenedesmus quadricauda

    Science.gov (United States)

    Vítová, Milada; Bišová, Kateřina; Zachleder, Vilém

    2011-01-01

    DNA damage is a threat to genomic integrity in all living organisms. Plants and green algae are particularly susceptible to DNA damage especially that caused by UV light, due to their light dependency for photosynthesis. For survival of a plant, and other eukaryotic cells, it is essential for an organism to continuously check the integrity of its genetic material and, when damaged, to repair it immediately. Cells therefore utilize a DNA damage response pathway that is responsible for sensing, reacting to and repairing damaged DNA. We have studied the effect of 5-fluorodeoxyuridine, zeocin, caffeine and combinations of these on the cell cycle of the green alga Scenedesmus quadricauda. The cells delayed S phase and underwent a permanent G2 phase block if DNA metabolism was affected prior to S phase; the G2 phase block imposed by zeocin was partially abolished by caffeine. No cell cycle block was observed if the treatment with zeocin occurred in G2 phase and the cells divided normally. CDKA and CDKB kinases regulate mitosis in S. quadricauda; their kinase activities were inhibited by Wee1. CDKA, CDKB protein levels were stabilized in the presence of zeocin. In contrast, the protein level of Wee1 was unaffected by DNA perturbing treatments. Wee1 therefore does not appear to be involved in the DNA damage response in S. quadricauda. Our results imply a specific reaction to DNA damage in S. quadricauda, with no cell cycle arrest, after experiencing DNA damage during G2 phase. PMID:21603605

  10. Cultivation of freshwater microalga Scenedesmus sp. using a low-cost inorganic fertilizer for enhanced biomass and lipid yield.

    Science.gov (United States)

    Nayak, Manoranjan; Thirunavoukkarasu, Manikkannan; Mohanty, Rama C

    2016-01-01

    The potential of an inorganic fertilizer as an alternative nutrient source for the cultivation of Scenedesmus sp. IMMTCC-6 was investigated. With a preliminary study at a shake-flask scale, the microalgae cultivation was scaled up in a photobioreactor containing an inorganic fertilizer medium. Microalgae cultured in a shake flask containing 0.1 g L(-1) of urea and 1.0 g L(-1) of NPK (Nitrogen: Phosphorus: Potassium) fertilizers showed a promising result in biomass productivity. During the scale-up study in a photobioreactor the specific growth rate (μ d(-1)), biomass yield (g L(-1)), and total biomass productivity (mg L(-1) d(-1)), was found to be 0.265, 1.19 and 66.1, respectively. The lipid yield (%) as per dry cell weight (DCW) and lipid productivity (mg L(-1) d(-1)) was found to be a maximum of 28.55 and 18.87, respectively, in a stationary phase of the microalgae growth. The fatty acids methyl ester profile was proven to be desirable for biodiesel production.

  11. Algicidal effects of aqueous leaf extracts of neem (Azadirachta indica on Scenedesmus quadricauda (Turp. de Brébission

    Directory of Open Access Journals (Sweden)

    Mathias Ahii Chia

    2016-03-01

    Full Text Available The application of synthetic algaecides for the control of algae produces by-products that are sometimes toxic to the environment. There is a need for natural and cheap alternatives to synthetic algaecides. In the present study, we investigated the potential of aqueous crude extract of Azadirachta indica to inhibit the growth of Scenedesmus quadricauda. Phytochemical screening of the extract revealed the presence of groups of bioactive compounds that are capable of inhibiting microalgal growth. Chlorophyll a concentration, dry weight production and cell density of microalga decreased with increasing crude extract concentration. After three days of exposure, the 1000 mg/L extract concentration resulted in complete growth inhibition and cell lysis. Furthermore, the ability of S. quadricauda to form multi-celled coenobial structures was compromised in a concentration dependent manner. In general, catalase and peroxidase activities of the microalga were upregulated with increasing extract concentration. These results imply that aqueous neem extract may provide a cheap and ecofriendly alternative for the control of microalgae in aquatic ecosystems.

  12. Influence of the CO2 absorbent monoethanolamine on growth and carbon fixation by the green alga Scenedesmus sp.

    Science.gov (United States)

    Choi, Wookjin; Kim, Garam; Lee, Kisay

    2012-09-01

    The influence of monoethanolamine (MEA) as a CO(2) absorbent on photoautotrophic culture of CO(2)-fixing microalgae was investigated. When 300 ppm MEA (4.92 mM) was added to blank culture medium, the dissolved inorganic carbon and the molar absorption ratio increased to 51.0mg/L and 0.34 mol CO2 = mol MEA, respectively, which was an almost 6-fold increase in CO(2) solubility. When free MEA up to 300 mg/L was added to a green alga Scenedesmus sp. culture that was supplied 5% (v/v) CO(2) at 0.1 vvm, both cell growth rate and final cell density were enhanced compared to when no MEA was added. The cell growth rate reached 288.6 mg/L/d, which was equivalent to 539.6 mg-CO(2)/L/d as a CO(2)-fixation rate and enhancement of about 63.0% compared to not adding MEA. Chlorophyll-a content and nitrate consumption rate increased correspondingly. MEA doses higher than 400mg/L inhibited cell growth, probably due to toxicity of the carbamate intermediate. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Green microalga Scenedesmus acutus grown on municipal wastewater to couple nutrient removal with lipid accumulation for biodiesel production.

    Science.gov (United States)

    Sacristán de Alva, Manuel; Luna-Pabello, Víctor M; Cadena, Erasmo; Ortíz, Edgar

    2013-10-01

    The green microalga Scenedesmus acutus was cultivated in two different municipal wastewater discharges (pre- and post-treated), and was compared to a culture medium with basic nutrients (20% of N, P, K), in order to study the simultaneous potential of nutrient removal and lipid accumulation ability. The highest level of nutrient removal was found in the pretreated wastewater discharge (achieving a high removal of phosphorus [66%] and organic nitrogen [94%]). Likewise, better results on biomass productivity and lipid accumulation were found in cultures using pretreated wastewater compared to enriched medium, obtaining 79.9 mg/L, and 280 mg/L, respectively. Since the best results were found in pretreated wastewater, the biodiesel preparation was performed using said medium at small-scale. After cultivation, 249.4 mg/L of biodiesel were obtained. According to this analysis, S. acutus could be used for wastewater treatment producing biomass with a suitable content of lipids, convenient for biodiesel production. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. DNA damage during G2 phase does not affect cell cycle progression of the green alga Scenedesmus quadricauda.

    Directory of Open Access Journals (Sweden)

    Monika Hlavová

    Full Text Available DNA damage is a threat to genomic integrity in all living organisms. Plants and green algae are particularly susceptible to DNA damage especially that caused by UV light, due to their light dependency for photosynthesis. For survival of a plant, and other eukaryotic cells, it is essential for an organism to continuously check the integrity of its genetic material and, when damaged, to repair it immediately. Cells therefore utilize a DNA damage response pathway that is responsible for sensing, reacting to and repairing damaged DNA. We have studied the effect of 5-fluorodeoxyuridine, zeocin, caffeine and combinations of these on the cell cycle of the green alga Scenedesmus quadricauda. The cells delayed S phase and underwent a permanent G2 phase block if DNA metabolism was affected prior to S phase; the G2 phase block imposed by zeocin was partially abolished by caffeine. No cell cycle block was observed if the treatment with zeocin occurred in G2 phase and the cells divided normally. CDKA and CDKB kinases regulate mitosis in S. quadricauda; their kinase activities were inhibited by Wee1. CDKA, CDKB protein levels were stabilized in the presence of zeocin. In contrast, the protein level of Wee1 was unaffected by DNA perturbing treatments. Wee1 therefore does not appear to be involved in the DNA damage response in S. quadricauda. Our results imply a specific reaction to DNA damage in S. quadricauda, with no cell cycle arrest, after experiencing DNA damage during G2 phase.

  15. nfluence of reducing and oxidizing compounds and of the redox potential of the medium on the biomass of Scenedesmus quadricauda (Turp. Breb.

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    Stefan Gumiński

    2014-01-01

    Full Text Available The influence was investigated of several concentrations of the reducing agents: cysteine, glutathione, ascorbic acid, pyracatechol and of the oxidizing agents: KMnO4, K4Cr2O7 and H2O2 on the total dry weight increment and that of protein with reference to redox potential changes of the medium in Scenedesmus quadricauda cultures. The culture was run in a photothermostat. It was found that the reducing compounds had as a rule a stimulating influence under 24-h illumdnation, whereas the oxidilzing agents gave the same effect when a period of 7-h darkness was applied within 24 h.

  16. The Path of Carbon in Photosynthesis XIII. pH Effects in C{sup 14}O{sub 2} Fixation by Scenedesmus

    Science.gov (United States)

    Ouellet, C.; Benson, A. A.

    1951-10-23

    The rates of photosynthesis and dark fixation of C{sup 14}O{sub 2} in Scenedesmus have been compared in dilute phosphate buffers of 1.6 to 11.4 pH; determination of C{sup 14} incorporation into the various products shows enhancement of uptake in an acid medium into sucrose, polysaccharides, alanine and serine, in an alkaline medium into malic asparctic acids. kinetic experiments at extreme pH values suggest that several paths are available for CO{sub 2} assimilation. A tentative correlation of the results with the pH optima of some enzymes and resultant effects upon concentrations of intermediates is presented.

  17. Allelopathic interactions between the macrophyte Egeria densa and plankton (alga, Scenedesmus acutus and cladocerans, Simocephalus spp.: a laboratory study

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    Cristian A. Espinosa-Rodríguez

    2016-03-01

    Full Text Available Allelopathic interactions between macrophytes and zooplankton are important to understand the plankton dynamics in shallow waterbodies. Egeria densa is a native, perennial, submerged macrophyte in the tropical and subtropical zones of South America. It has been introduced to Central and North America and is now common in many Mexican lakes. This macrophyte produces chemical substances that negatively affect some phytoplankton species. However, it is not clear how zooplankton species adapt different life history strategies in the chemical presence of this macrophyte. Here, we tested the direct and indirect effects of allelochemicals released by E. densa on the population growth of Scenedesmus acutus and on the demographic variables of three species of Simocephalus, S. exspinosus, S. serrulatus and S. mixtus (via alga exposed to the macrophyte allelochemicals. To quantify the effect of E. densa on S. acutus we set up four treatments: control, artificial Egeria, natural Egeria and allelochemicals from Egeria. To test the allelochemical effects on Simocephalus species, we compared four treatments: Control, indirect effect (using S. acutus grown on Egeria-allelochemicals, direct effect (using Egeria-conditioned medium and together with both these kinds of direct and indirect effects. Scenedesmus had the highest cell density in the presence of allelochemicals from Egeria, followed by controls. The specific algal growth rate (µ between control and allelochemicals treatment was not significant (P<0.05. However, the µ of alga in the presence of artificial or natural Egeria was significantly lower than controls or in treatment involving allelochemicals. The age-specific survivorship of the three cladoceran species was longer in treatments containing Egeria-conditioned medium. Cladocerans receiving Egeria conditioned-medium and algae cultured on macrophyte-allelochemicals also had a longer survivorship. Daily fecundity of S. serrulatus increased after

  18. Demography of zooplankton (Anuraeopsis fissa, Brachionus rubens and Moina macrocopa fed Chlorella vulgaris and Scenedesmus acutus cultured on different media

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    Jesús Morales-Ventura

    2012-09-01

    Full Text Available Generally zooplankton growth is often limited by the quality of their algal diet. A cheaper common practice in aquaculture, is to culture algae with fertilizers; however, the demography of zooplankton when fed these algae has not yet been evaluated. We studied the population growth and life table demography of the rotifers Anuraeopsis fissa and Brachionus rubens, and the cladoceran Moina macrocopa. For this, the algae Scenedesmus acutus or Chlorella vulgaris were cultured on defined (Bold’s basal medium or the commercial liquid fertilizer (Bayfolan. Experiments were conducted at one algal concentration 1.0x10(6cells/mL of C. vulgaris or its equivalent dry weight of 0.5x10(6cells/mL of S. acutus. The population dynamics were tested at 23±1ºC in 100mL transparent jars, each with 50mL of the test medium, with an initial density of 0.5indiv/mL, for a total of 48 test jars (3 zooplankton 2 algal species x 2 culture media x 4 replicates. For the life table experiments with M. macrocopa, we introduced 10 neonates (<24h old into each test jar containing the specific algal type and concentration. For the rotifer experiments, we set 5mL tubes with one neonate each and 10 replicates for each algal species and culture medium. We found that the average rotifer life span was not influenced by the diet, but for M. macrocopa fed S. acutus cultured in Bold’s medium, the average lifespan was significantly lower than with the other diets. The gross and net reproductive rates of A. fissa (ranging from 18-36 offspring per female were significantly higher for C. vulgaris cultured in Bold medium. Regardless of the culture medium, Chlorella resulted in significantly higher gross and net reproductive rates for B. rubens than S. acutus diets. The reproductive rates of M. macrocopa were significantly higher in all the tested diets except when fed with S. acutus in Bold medium. The population increase rate, derived from growth experiments of A. fissa and B. rubens

  19. Combined biocidal action of silver nanoparticles and ions against Chlorococcales (Scenedesmus quadricauda, Chlorella vulgaris) and filamentous algae (Klebsormidium sp.).

    Science.gov (United States)

    Zouzelka, Radek; Cihakova, Pavlina; Rihova Ambrozova, Jana; Rathousky, Jiri

    2016-05-01

    Despite the extensive research, the mechanism of the antimicrobial and biocidal performance of silver nanoparticles has not been unequivocally elucidated yet. Our study was aimed at the investigation of the ability of silver nanoparticles to suppress the growth of three types of algae colonizing the wetted surfaces or submerged objects and the mechanism of their action. Silver nanoparticles exhibited a substantial toxicity towards Chlorococcales Scenedesmus quadricauda, Chlorella vulgaris, and filamentous algae Klebsormidium sp., which correlated with their particle size. The particles had very good stability against agglomeration even in the presence of multivalent cations. The concentration of silver ions in equilibrium with nanoparticles markedly depended on the particle size, achieving about 6 % and as low as about 0.1 % or even less for the particles 5 nm in size and for larger ones (40-70 nm), respectively. Even very limited proportion of small particles together with larger ones could substantially increase concentration of Ag ions in solution. The highest toxicity was found for the 5-nm-sized particles, being the smallest ones in this study. Their toxicity was even higher than that of silver ions at the same silver concentration. When compared as a function of the Ag(+) concentration in equilibrium with 5-nm particles, the toxicity of ions was at least 17 times higher than that obtained by dissolving silver nitrite (if not taking into account the effect of nanoparticles themselves). The mechanism of the toxicity of silver nanoparticles was found complex with an important role played by the adsorption of silver nanoparticles and the ions released from the particles on the cell surface. This mechanism could be described as some sort of synergy between nanoparticles and ions. While our study clearly showed the presence of this synergy, its detailed explanation is experimentally highly demanding, requiring a close cooperation between materials scientists

  20. Cultivo de las microalgas dulceacuícolas Kirchneriella obesa, Scenedesmus quadricauda y Chlorococcum infusorium empleando tres medios de cultivo

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    A. A. Ortega-Salas

    2012-01-01

    Full Text Available Se cultivaron las microalgas dulceacuícolas Kirchneriella obesa (G. S. West Schmidle 1893, Scenedesmus quadricauda (Chodat, Turpin Bréb 1835 y Chlorococcum infusorium (Schrank Meneghini 1842, con el propósito comparar las tasas de crecimiento y su rendimiento en tres medios de cultivo, el F/2 de Guillard, Fert I y Fert II. El agua utilizada se pasó en filtros de cinco, uno y 0.45 mm, y se trató con luz ultravioleta. La temperatura varió de 24 a 25°C. Se cultivaron en un sistema de volumen creciente a partir de recipientes de 62.5 mL, duplicando el medio de cultivo cada 24 h, con el fin de completar 32 L en nueve días. Cada 24 h se obtuvieron tres muestras de 1 a 10 mL del cultivo, se preservaron en una solución de lugol y se calculó la concentración de las microalgas cada 24 h. El número total de células de las tres especies aumentó de manera exponencial hasta el final de los experimentos en los medios de cultivo F/2 y Fert I; esto no fue así con el medio Fert II, en el cual la tasa de duplicación y el número total de divisiones fueron más bajas. El medio F/2 y el Fert I ofrecieron mejores resultados que el Fert II. Los medios Fert I y Fert II tienen un valor económico más bajo que el medio F/2. El crecimiento y el rendimiento fueron mejores con el medio F/2, seguido por FI y FII.

  1. Selection and evaluation of CO2 tolerant indigenous microalga Scenedesmus dimorphus for unsaturated fatty acid rich lipid production under different culture conditions.

    Science.gov (United States)

    Vidyashankar, S; Deviprasad, K; Chauhan, V S; Ravishankar, G A; Sarada, R

    2013-09-01

    Five indigenous microalgal strains of Scenedesmus, Chlorococcum, Coelastrum, and Ankistrodesmus genera, isolated from Indian fresh water habitats, were studied for carbon-dioxide tolerance and its effect on growth, lipid and fatty acid profile. Scenedesmus dimorphus strain showed maximum growth (1.5 g/L) and lipid content (17.83% w/w) under CO2 supplementation, hence selected for detailed evaluation. The selected strain was alkaline adapted but tolerated (i) wide range of pH (5-11); (ii) elevated salinity levels (up to 100 mM, NaCl) with low biomass yields and increased carotenoids (19.34 mg/g biomass); (iii) elevated CO2 levels up to 15% v/v with enhancement in specific growth rate (0.137 d(-1)), biomass yield (1.57 g/L), lipid content (19.6% w/w) and CO2 biofixation rate (0.174 g L(-1) d(-1)). Unsaturated fatty acid content (alpha linolenic acid) increased with CO2 supplementation in the strain. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Evaluation of novel thermo-resistant Micractinium and Scenedesmus sp. for efficient biomass and lipid production under different temperature and nutrient regimes.

    Science.gov (United States)

    Sonmez, Cagla; Elcin, Evrim; Akın, Dilan; Oktem, Huseyin Avni; Yucel, Meral

    2016-07-01

    Despite the vast interest in microalgae as feedstock for biodiesel production, relatively few studies examined their response to diurnal temperature fluctuation. Here, we describe biomass and lipid productivities and fatty acid profiles of thermo-resistant Micractinium sp. and Scenedesmus sp. grown in batch cultures in a laboratory set-up that mimics a typically warm summer day in Central Anatolia with a 16-h light temperature of 30°C and 8-h dark temperature of 16°C (30°C (day)/16°C (night)). Both strains can survive a temperature range of 10-50°C. We found the lipid productivities of Micractinium sp. and Scenedesmus sp. as 30/21mgL(-1)d(-1) and 6/7mgL(-1)d(-1), respectively during the 30°C (day)/16°C (night) cycle. Saturated fatty acid content increased with increasing temperature. Additionally, we cultured Micractinium sp. under Nitrogen (N) and Phosphorus (P) limiting conditions. Highest lipid productivity of 85.4±2mgL(-1)d(-1) was obtained under P-depletion during exponential growth phase. Oleic acid amount also increased eight fold during P-deplete. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Boosting TAG Accumulation with Improved Biodiesel Production from Novel Oleaginous Microalgae Scenedesmus sp. IITRIND2 Utilizing Waste Sugarcane Bagasse Aqueous Extract (SBAE).

    Science.gov (United States)

    Arora, Neha; Patel, Alok; Pruthi, Parul A; Pruthi, Vikas

    2016-09-01

    This investigation utilized sugarcane bagasse aqueous extract (SBAE), a nontoxic, cost-effective medium to boost triacylglycerol (TAG) accumulation in novel fresh water microalgal isolate Scenedesmus sp. IITRIND2. Maximum lipid productivity of 112 ± 5.2 mg/L/day was recorded in microalgae grown in SBAE compared to modified BBM (26 ± 3 %). Carotenoid to chlorophyll ratio was 12.5 ± 2 % higher than in photoautotrophic control, indicating an increase in photosystem II activity, thereby increasing growth rate. Fatty acid methyl ester (FAME) profile revealed presence of C14:0 (2.29 %), C16:0 (15.99 %), C16:2 (4.05 %), C18:0 (3.41 %), C18:1 (41.55 %), C18:2 (12.41), and C20:0 (1.21 %) as the major fatty acids. Cetane number (64.03), cold filter plugging property (-1.05 °C), and oxidative stability (12.03 h) indicated quality biodiesel abiding by ASTM D6751 and EN 14214 fuel standards. Results consolidate the candidature of novel freshwater microalgal isolate Scenedesmus sp. IITRIND2 cultivated in SBAE, aqueous extract made from copious, agricultural waste sugarcane bagasse to increase the lipid productivity, and could further be utilized for cost-effective biodiesel production.

  4. Effects of organic carbon source and light-dark period on growth and lipid accumulation of Scenedesmus sp. AARL G022

    Directory of Open Access Journals (Sweden)

    Doungpen Dittamart

    2014-08-01

    Full Text Available The levels of different organic carbon supplements in a mixotrophic culture were optimised to enhance biomass and lipid accumulation in Scenedesmus sp. AARL G022. The supplement nutrients, viz. glucose, glycerol and sodium acetate, were compared with non-organic carbon supplement (photoautotrophic culture. The most suitable carbon source was found to be 0.05M glucose, giving a yield of 2.78 ± 0.86 g.L -1 of biomass and 233.68 ± 35.34 mg.L -1 of crude lipid. The highest yield of biomass (4.04 ± 0.36 g.L -1 was obtained from a light-dark cycle of 24:0 hr. The highest crude lipid yield of 396.35 ± 11.60 mg.L -1 was obtained from a light-dark cycle of 16:8 hr. The optimised condition for culturing Scenedesmus sp. AARL G022 is to cultivate it under a mixotrophic condition using 0.05M of glucose supplement with a light-dark cycle of 16:8 hr.

  5. Toxic effects of anthraquinone and phenanthrenequinone upon Scenedesmus strains (green algae) at low and elevated concentration of CO2.

    Science.gov (United States)

    Tukaj, Zbigniew; Aksmann, Anna

    2007-01-01

    Short-term (24h) experiments were performed to examine the effect of anthraquinone (ANTQ) and phenanthrenequinone (PHEQ) on two Scenedesmus armatus strains (B1-76 and 276-4d) grown in a batch culture system aerated with CO2 at a low (0.1%) or elevated (2%) concentration. ANTQ at concentrations within the range of 0.156-1.250 mg dm-3 inhibited the growth of B1-76 population in a concentration-dependent manner, and calculated EC50 for low-CO2 cells was 0.56 mg dm-3. The toxic effect of ANTQ on this strain was more pronounced in high-CO2 cells, where not only growth but also photosynthesis, respiration and SOD activity were significantly inhibited. In contrast, except for SOD activity, no ANTQ effects on strain 276-4d were found. PHEQ at concentrations within the range of 0.063-0.125 mg dm-3 inhibited the growth of B1-76 population in a concentration-dependent manner. The value of EC50 for low-CO2 B1-76 cells was 0.10 mg dm-3. PHEQ inhibited the growth of both strains regardless of CO2 concentration. In B1-76 cells affected by PHEQ, inhibition of photosynthesis was independent of the CO2 level, whereas the SOD activity was much higher in cultures aerated with 2% than with 0.1% CO2. Higher toxicity of PHEQ to strain 276-4d grown at 2% CO2 was accompanied by strong inhibition of photosynthesis, while in low-CO2 cells this process was slightly stimulated. The SOD activity in both low- and high-CO2 cells of strain 276-4d treated with PHEQ was 2-3 times higher compared with the controls. The pattern of SOD isoforms (PAGE analysis) obtained from cells exposed to ANTQ or PHEQ did not change compared with the controls, but the location of the SOD isoforms bands on gel was affected by the concentration of CO2. The results suggest that the strain-specific toxicity of ANTQ and PHEQ may result from oxidative stress. In addition, carbon dioxide appears to play an important role in the toxicity of quinones to algae.

  6. Chlorococcales nuevas para el embalse Paso de las Piedras (Buenos Aires, Argentina New Chlorococcales for Paso de las Piedras Reservoir (Buenos Aires, Argentine

    Directory of Open Access Journals (Sweden)

    Carolina Fernández

    2005-12-01

    Full Text Available En el presente trabajo se citan e ilustran 22 especies pertenecientes al orden Chlorococcales (Chlorophyceae, Chlorophyta halladas en el embalse Paso de las Piedras que representan nuevas citas para este ambiente. Pseudokirchneriella subcapitata, Tetraedron hemisphaericum y Scenedesmus semipulcher constituyen nuevas citas para la República Argentina.In this paper, we record and illustrate 22 species of Chlorococcales (Chlorophyceae, Chlorophyta found in Paso de las Piedras Reservoir, which are new records for this area. Pseudokirchneriella subcapitata, Tetraedron hemisphaericum and Scenedesmus semipulcher are new for Argentina.

  7. Exploration of a mechanism for the production of highly unsaturated fatty acids in Scenedesmus sp. at low temperature grown on oil crop residue based medium.

    Science.gov (United States)

    Lu, Qian; Li, Jun; Wang, Jinghan; Li, Kun; Li, Jingjing; Han, Pei; Chen, Paul; Zhou, Wenguang

    2017-11-01

    The ability of algae to produce lipids comprising of unsaturated fatty acids varies with strains and culture conditions. This study investigates the effect of temperature on the production of unsaturated fatty acids in Scenedesmus sp. grown on oil crop residue based medium. At low temperature (10°C), synthesis of lipids compromising of high contents of unsaturated fatty acids took place primarily in the early stage while protein accumulation mainly occurred in the late stage. This stepwise lipid-protein synthesis process was found to be associated with the contents of acetyl-CoA and α-KG in the algal cells. A mechanism was proposed and tested through simulation experiments which quantified the carbon flux allocation in algal cells at different cultivation stages. It is concluded that low culture temperature such as 10°C is suitable for the production of lipids comprising of unsaturated fatty acids. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Bio-oil production and removal of organic load by microalga Scenedesmus sp. using culture medium contaminated with different sugars, cheese whey and whey permeate.

    Science.gov (United States)

    Borges, Wesley da Silva; Araújo, Breno Severiano Alves; Moura, Lucas Gomes; Coutinho Filho, Ubirajara; de Resende, Miriam Maria; Cardoso, Vicelma Luiz

    2016-05-15

    The objective of this study was to evaluate the bio-oil production and the organic load removal using the microalga Scenedesmus sp. The cultivation was carried out in reactors with a total volume of 3 L and 0.7 vvm aeration, with illumination in photoperiods of 12 h light/12 h dark for 12 days. The following sugar concentrations were tested: 2.5, 5.0 and 10 g/L of glucose, lactose, fructose and galactose with 10% inoculum volume. After experiments were performed with cheese whey in natura and cheese whey permeate with different lactose concentrations (1.5, 2.5, 3.5 and 5.0 g/L). In these experiments the inoculum concentrations were 10, 15, 20 and 30% (v/v). The results showed that this microalga was effective for the production of lipids when it was cultivated in medium with cheese whey in natura with 2.5 g/L of lactose and 20% inoculum (v/v). Using cheese whey in natura at the concentration of 3.5 g/L of lactose and 30% (v/v) of inoculum obtained 77.9% of TOC removal and 38.447 mg of TOC removed/mg oil produced. It was also observed that when there is increased production of bio-oil, there is less removal of organic matter. The addition of glucose, fructose or galactose in the medium did not enhance the production of bio-oil by Scenedesmus sp. when compared to lactose, but increased the organic matter removal. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Adaptation of Selenastrum capricornutum (Chlorophyceae) to copper

    Science.gov (United States)

    Kuwabara, J.S.; Leland, H.V.

    1986-01-01

    Selenastrum capricornutum Printz, growing in a chemically defined medium, was used as a model for studying adaptation of algae to a toxic metal (copper) ion. Cells exhibited lag-phase adaptation to 0.8 ??M total Cu (10-12 M free ion concentration) after 20 generations of Cu exposure. Selenastrum adapted to the same concentration when Cu was gradually introduced over an 8-h period using a specially designed apparatus that provided a transient increase in exposure concentration. Cu adaptation was not attributable to media conditioning by algal exudates. Duration of lag phase was a more sensitive index of copper toxicity to Selenastrum that was growth rate or stationary-phase cell density under the experimental conditions used. Chemical speciation of the Cu dosing solution influenced the duration of lag phase even when media formulations were identical after dosing. Selenastrum initially exposed to Cu in a CuCl2 injection solution exhibited a lag phase of 3.9 d, but this was reduced to 1.5 d when a CuEDTA solution was used to achieve the same total Cu and EDTA concentrations. Physical and chemical processes that accelerated the rate of increase in cupric ion concentration generally increased the duration of lag phase. ?? 1986.

  10. Simultaneous remediation of nutrients from liquid anaerobic digestate and municipal wastewater by the microalga Scenedesmus sp. AMDD grown in continuous chemostats.

    Science.gov (United States)

    Dickinson, K E; Bjornsson, W J; Garrison, L L; Whitney, C G; Park, K C; Banskota, A H; McGinn, P J

    2015-01-01

    The primary aim of this study was to investigate the capacity of a microalga, Scenedesmus sp. AMDD, to remediate nutrients from municipal wastewater, either as the sole nutrient source or after blending with wastewater obtained from the anaerobic digestion of swine manure. A complimentary aim was to study and define the effects of these wastewaters on microalgal growth, biomass productivity and composition which have important implications for a commercial biofuels production system. A microalga, Scenedesmus sp. AMDD, was grown in continuous chemostats in municipal wastewater or wastewater supplemented with 1·6× or 2·4× higher levels of nitrogen (N) obtained through supplementation with anaerobic digestates. Biomass productivity increased with increasing nutrient supplementation, but was limited by light at high cell densities. Cellular quotas of carbon (C), nitrogen and phosphorus (P) all increased in direct proportion to their concentrations in the combined wastewaters. At higher cell densities, total carbohydrate decreased while protein increased. Fatty acid content remained relatively constant. Under high nutrient levels, the fatty acid profiles contained a higher concentration of polyunsaturated fatty acids at the expense of monounsaturated fatty acids. Chlorophyll a was 2·5 times greater in the treatment of greatest nutrient supplementation compared to the treatment with the least. Ammonium (NH4(+)) and phosphate (PO4(3-)) were completely removed by algal growth in all treatments and with maximal removal rates of 41·2 mg N l(-1) d(-1) and 6·7 mg P l(-1) d(-1) observed in wastewater amended with 2·4× higher N level. The study is the first to report stable, long-term continuous algal growth and productivity obtained by combining wastewaters of different sources. The study is supported by detailed analyses of the composition of the cultivated biomass and links composition to the nutrient and light availabilities in the cultures. Simultaneous remediation

  11. +91 1662 263153, Fax: +91 1662 277942 Chromium Tolerance and ...

    African Journals Online (AJOL)

    Michael Horsfall

    Horcasitas, C; Canizares-Villanueva, R O; (2007). Growth, photosynthetic and respiratory responses to sub-lethal copper concentrations in Scenedesmus incrassatulus. (Chlorophyceae). Chemosphere,. 67:2274-2281. Salguero, A; De La Morena, B; Viagara, J; (2003). Carotenoids as protective response against oxidative.

  12. Utilization of agricultural residues of pineapple peels and sugarcane bagasse as cost-saving raw materials in Scenedesmus acutus for lipid accumulation and biodiesel production.

    Science.gov (United States)

    Rattanapoltee, Panida; Kaewkannetra, Pakawadee

    2014-07-01

    The aim of this study is to optimize the lipid accumulation in microalgae by using two agricultural residues of pineapple peels and sugarcane bagasse as low-cost organic carbon sources. Green microalgae Scenedesmus acutus was isolated and selected for cultivation. Effects of three initial sugar concentrations and the stage for adding sugar during cultivation on biomass and lipid production were investigated. The results clearly showed that two-stage cultivation is more suitable than one-stage. The maximum biomass concentration and productivity were obtained at 3.85 g/L and 160.42 mg/L/day when sugarcane bagasse was used. The highest lipid content and lipid yield was reached at 28.05 % and 0.93 g/L when pineapple peels were used, while in the case of sugarcane bagasse, 40.89 % and 1.24 g/L lipid content and yield were obtained. Lipid content was found in normal condition (autotrophic) at 17.71 % which was approximately 2.13-fold lower than when sugarcane bagasse was used (40.89 %). Biodiesel production via in situ transesterification was also investigated; the main fatty acids of palmitic acid and oleic acid were found. This work indicates that using agricultural residues as organic carbon sources could be able to increase lipid content and reduce the cost of biofuel production.

  13. Sugar-mediated transcriptional regulation of the Gap gene system and concerted photosystem II functional modulation in the microalga Scenedesmus vacuolatus.

    Science.gov (United States)

    Valverde, Federico; Ortega, José M; Losada, Manuel; Serrano, Aurelio

    2005-08-01

    Partial cDNAs corresponding to the GapA, GapC and GapN genes that encode the three different glyceraldehyde-3-phosphate dehydrogenases (GAPDHs) of the green microalga Scenedesmus vacuolatus SAG 211-8b have been cloned and characterized. Northern blot experiments, as well as immunoblots and activity measurements, demonstrate a differential regulation by sugars of the components of the algal Gap gene system. Addition of glucose or other metabolizable sugars to photoautotrophic cultures promoted a drastic repression of the GapA gene and depletion to negligible levels of the corresponding GAPDHA, a chloroplastic protein involved in photosynthetic CO2 assimilation. By contrast, expression of the GapC and GapN genes encoding their cytosolic counterparts involved in glycolysis was enhanced. However, no down-regulation of the GapA gene by glucose took place in the dark, indicating that the observed effect is associated with sugar assimilation in the light. Likewise, glucose promoted in illuminated algal cultures a severe decrease of photosystem II functionality, estimated by O2 evolution activity, thermoluminescence emission and D1 protein level, while again, no effect was observed in the dark. On the basis of the correlation found between photosystem II performance and sugar transcriptional regulation of the GapA gene, a scenario of sugar-mediated regulation of photosynthetic metabolism in microalgae is proposed that will help to explain the so-called glucose bleaching effect in photosynthetic eukaryotes.

  14. Evaluation of fatty acid profile and biodiesel properties of microalga Scenedesmus abundans under the influence of phosphorus, pH and light intensities.

    Science.gov (United States)

    Mandotra, S K; Kumar, Pankaj; Suseela, M R; Nayaka, S; Ramteke, P W

    2016-02-01

    The present study dealt with biomass, lipid concentration, fatty acid profile and biodiesel properties of microalga Scenedesmus abundans under different phosphate concentrations, pH and light intensities, one at a time. Among different phosphate concentrations, higher biomass (770.10±11.0mg/L) and lipid concentration (176.87±4.6mg/L) were at the concentration of 60mg/L. Light intensity at 6000lux yielded higher biomass and lipid concentration of 742.0±9.7 and 243.15±9.1mg/L, respectively. The biomass (769.0±12.3mg/L) and lipid (179.47±5.5mg/L) concentration were highest at pH 8 and pH 6, respectively. All the culture treatments showed marked effect on the fatty acid profile and biodiesel properties of the extracted oil. FAME derived biodiesel properties were compared with European biodiesel standards (EN 14214), Indian biodiesel standards (IS 15607) and American biodiesel standards (ASTM D 6751-08) to assess the suitability of algal oil as biodiesel feedstock. Copyright © 2015. Published by Elsevier Ltd.

  15. Effect of the temperature, pH and irradiance on the photosynthetic activity by Scenedesmus obtusiusculus under nitrogen replete and deplete conditions.

    Science.gov (United States)

    Cabello, Juan; Toledo-Cervantes, Alma; Sánchez, León; Revah, Sergio; Morales, Marcia

    2015-04-01

    This paper evaluates the effect of the irradiance, pH and temperature on the photosynthetic activity (PA) of Scenedesmus obtusiusculus under N-replete and N-deplete conditions through oxygen measurements. The highest PA values were 160 mgO2 gb(-1) h(-1) at 620 μmol m(-2) s(-1), 35 °C and pH of 8 under N-replete conditions and 3.3 mgO2 gb(-1) h(-1) at 100 μmol m(-2) s(-1), 28.5 °C and pH of 5.5 for N-deplete conditions. Those operation conditions were tested in a flat-panel photobioreactor. The biomass productivity was 0.97 gb L(-1) d(-1) under N-replete conditions with a photosynthetic efficiency (PE) of 4.4% yielding 0.85 gb mol photon(-1). Similar biomass productivity was obtained under N-deplete condition; and the lipid productivity was 0.34 gL L(-1) d(-1) with a PE of 7.8% yielding 0.39 gL mol photon(-1). The apparent activation and deactivation energies were 16.1 and 30 kcal mol(-1), and 11.9 and 15.3 kcal mol(-1), for N-replete and N-deplete conditions, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Growth and biochemical characteristics of an indigenous freshwater microalga, Scenedesmus obtusus, cultivated in an airlift photobioreactor: effect of reactor hydrodynamics, light intensity, and photoperiod.

    Science.gov (United States)

    Sarat Chandra, T; Aditi, S; Maneesh Kumar, M; Mukherji, S; Modak, J; Chauhan, V S; Sarada, R; Mudliar, S N

    2017-07-01

    The freshwater green algae, Scenedesmus obtusus, was cultivated in a 3.4 L airlift photobioreactor. The hydrodynamic parameters were estimated at different inlet gas flow rates (1, 2, 3, and 4 LPM) and their subsequent impact on the growth and biochemical characteristics of microalgae was studied. The biomass concentration and productivity increased with an increase in flow rates from 1 to 4 LPM. A maximum of 0.07 g L-1 day-1 productivity of biomass was attained at 3 LPM. An increase of total carbohydrate content from 19.6 to 26.4% was noticed with increment in the inlet flow rate of gas from 1 to 4 LPM. Major variations in total fatty acid content were not observed. The impact of light irradiance on growth and biochemical characteristics of S. obtusus was also evaluated. A maximum biomass productivity of 0.103 g L-1 day-1 was attained at an illumination of 150 μmol m-2 s-1 under continuous light. The major fatty acids reported were palmitic acid (C16:0), α-linolenic acid (C18:3), linoleic acid (C18:2), and oleic acid (C18:1). Biodiesel properties of the microalgae were estimated under various culture conditions. The light profile inside the airlift reactor was experimentally measured and the predictive modelling of light profile was also attempted.

  17. Evaluation of indigenous fresh water microalga Scenedesmus obtusus for feed and fuel applications: Effect of carbon dioxide, light and nutrient sources on growth and biochemical characteristics.

    Science.gov (United States)

    Sarat Chandra, T; Deepak, R S; Maneesh Kumar, M; Mukherji, S; Chauhan, V S; Sarada, R; Mudliar, S N

    2016-05-01

    Scenedesmus obtusus, a freshwater microalga, was evaluated for its growth and biochemical characteristics under various culture conditions. S. obtusus was tolerant at all tested CO2 concentrations up to 20%. Among the different nitrogen sources, urea showed enhanced biomass productivities up to 2-fold compared to control, where the nitrogen source was sodium nitrate. Light intensity and photoperiod had a significant effect on growth rate and biomass productivity. The growth rate was observed maximum under continuous light exposure at the light intensities, 30μmolm(-2)sec(-1) and 60μmolm(-2)sec(-1) The species was able to tolerate the salinity levels up to 25mM NaCl, where, the increase in the concentration of NaCl suppressed the growth. Ammonium acetate and glycine showed better growth rate and biomass productivity indicating mixotrophic ability of S. obtusus. Supplementation of acetate and bicarbonate significantly enhanced the biomass productivity. Biodiesel properties of S. obtusus cultivated at various culture conditions were estimated. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. A one-stage cultivation process for lipid- and carbohydrate-rich biomass of Scenedesmus obtusiusculus based on artificial and natural water sources.

    Science.gov (United States)

    Schulze, Christian; Reinhardt, Jakob; Wurster, Martina; Ortiz-Tena, José Guillermo; Sieber, Volker; Mundt, Sabine

    2016-10-01

    A one-stage cultivation process of the microalgae Scenedesmus obtusiusculus with medium based on natural water sources was developed to enhance lipids and carbohydrates. A medium based on artificial sea water, Baltic Sea water and river water with optimized nutrient concentrations compared to the standard BG-11 for nitrate (-75%), phosphate and iron (-90%) was used for cultivation. Although nitrate exhaustion over cultivation resulted in nitrate limitation, growth of the microalgae was not reduced. The lipid content increased from 6.0% to 19.9%, an increase in oleic and stearic acid was observed. The unsaponifiable matter of the lipid fraction was reduced from 19.5% to 11.4%. The carbohydrate yield rose from 45% to 50% and the protein content decreased from 32.4% to 15.9%. Using natural water sources with optimized nutrient concentrations could open the opportunity to modulate biomass composition and to reduce the cultivation costs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Biodegradation of benzo(a)pyrene by two freshwater microalgae Selenastrum capricornutum and Scenedesmus acutus: a comparative study useful for bioremediation.

    Science.gov (United States)

    García de Llasera, Martha Patricia; Olmos-Espejel, José de Jesús; Díaz-Flores, Gabriel; Montaño-Montiel, Adriana

    2016-02-01

    A comparative evaluation of the removal of benzo(a)pyrene (BaP) by sorption and degradation by two microalgal species, Selenastrum capricornutum and Scenedesmus acutus was performed. The monitoring of the amount of BaP remaining in the liquid culture media and the biomass along with the appearance of three metabolites (4,5 dihydrodiol-BaP; 7,8-dihydrodiol-BaP; and 9,10 dihydrodiol-BaP) at short time periods (from 0.25 to 72 h) in cultures exposed to BaP was made by high-performance liquid chromatography (HPLC) with fluorescence and UV detection. Complete removal of BaP was achieved by the two live microalgal species: S. capricornutum at 15 h of exposure (99%) and S. acutus at 72 h of exposure (95%). Sorption is an important phenomenon for BaP removal by S. capricornutum but biodegradation is the principal means of removing BaP in live cells. The formation of metabolites by S. capricornutum is rapid and seems to be proportional to the amount of the BaP added to cultures. In contrast, in these bioassays, most of the BaP removal of S. acutus is due to sorption rather than degradation. The appearance of metabolites in the cultures is very slow and at a low amount compared to cultures of S. capricornutum. The similarities and differences existing between the two microalgae are important for the establishment of the conditions for bioremediation.

  20. Farklı Ortamlarda Üretilmiş Scenedesmus acuminatus Alginin ve Ekmek Mayasının (Saccharomyces cerevisae Daphnia magna'nın Populasyon Artışına Etkisi.

    Directory of Open Access Journals (Sweden)

    Murtaza Ölmez

    2015-12-01

    Full Text Available Bu çalışmada, Daphnia magna’nın populasyon artışı üzerine dört farklı besinin (Scenedesmus ortamında üretilen alg, Scenedesmus ortamında üretilen alg+maya, inorganik gübreli ortamda üretilen alg+maya ve maya etkisi belirlenmiştir. Deneme her bir besin için 500 ml besin ortamı içeren 1 L kapasiteli 12 erlenmayerden (=4 food x 3 tekerrür oluşacak şekilde gerçekleştirilmiştir. Denemeye 24 saatten genç bireyler kullanılarak başlangıç yoğunluğu 5 birey/500 ml olarak başlanmış, bütün deneme gruplarındaki tekerrürlerin çoğunda, populasyon artışında azalmanın görüldüğü 28 günün sonunda deneme sonlandırıldı. Deneme sonunda maksimum birey sayısı 3600,00±41,00 birey/500 ml olarak 25. günde ve maksimum büyüme oranı ise 0,36±0,002/gün olarak 14. günde Scenedesmus ortamında üretilmiş algle (Scenedesmus acuminatus beslenen I. grupta saptanmıştır. Maya ilavesi birey sayısı ve büyüme oranında azalmaya yol açarken, sadece mayayla beslenen grubun populasyon artışı en düşük düzeyde olmuş ve diğer gruplardan istatistikî olarak önemli derecede farklılık göstermiştir (P

  1. Cell growth and lipid accumulation of a microalgal mutant Scenedesmus sp. Z-4 by combining light/dark cycle with temperature variation.

    Science.gov (United States)

    Ma, Chao; Zhang, Yan-Bo; Ho, Shih-Hsin; Xing, De-Feng; Ren, Nan-Qi; Liu, Bing-Feng

    2017-01-01

    The light/dark cycle is one of the most important factors affecting the microalgal growth and lipid accumulation. Biomass concentration and lipid productivity could be enhanced by optimization of light/dark cycles, and this is considered an effective control strategy for microalgal cultivation. Currently, most research on effects of light/dark cycles on algae is carried out under autotrophic conditions and little information is about the effects under mixotrophic cultivation. At the same time, many studies related to mixotrophic cultivation of microalgal strains, even at large scale, have been performed to obtain satisfactory biomass and lipid production. Therefore, it is necessary to investigate cellular metabolism under autotrophic and mixotrophic conditions at different light/dark cycles. Even though microalgal lipid production under optimal environmental factors has been reported by some researchers, the light/dark cycle and temperature are regarded as separate parameters in their studies. In practical cases, light/dark cycling and temperature variation during the day occur simultaneously. Therefore, studies about the combined effects of light/dark cycles and temperature variation on microalgal lipid production are of practical value, potentially providing significant guidelines for large-scale microalgal cultivation under natural conditions. In this work, cell growth and lipid accumulation of an oleaginous microalgal mutant, Scenedesmus sp. Z-4, were investigated at five light/dark cycles (0 h/24 h, 8 h/16 h, 12 h/12 h, 16 h/8 h, and 24 h/0 h) in batch culture. The results showed that the optimal light/dark cycle was 12 h/12 h, when maximum lipid productivity rates of 56.8 and 182.6 mg L-1 day-1 were obtained under autotrophic and mixotrophic cultivation, respectively. Poor microalgal growth and lipid accumulation appeared in the light/dark cycles of 0 h/24 h and 24 h/0 h under autotrophic condition. Prolonging the light duration was

  2. Ionic liquids toxicity on fresh water microalgae, Scenedesmus quadricauda, Chlorella vulgaris &Botryococcus braunii; selection criterion for use in a two-phase partitioning bioreactor (TPPBR).

    Science.gov (United States)

    Quraishi, Khurrum Shehzad; Bustam, Mohamad Azmi; Krishnan, Sooridarsan; Aminuddin, Noor Fathanah; Azeezah, Noraisyah; Ghani, Noraini Abd; Uemura, Yoshimitsu; Lévêque, Jean Marc

    2017-10-01

    A promising method of Carbon dioxide (CO2) valorization is to use green microalgae photosynthesis to process biofuel. Two Phase Partitioning Bioreactors (TPPBR) offer the possibility to use non-aqueous phase liquids (NAPL) to enhance CO2 solubility; thus making CO2 available to maximize algae growth. This requires relatively less toxic hydrophobic Ionic Liquids (ILs) that comprise a new class of ionic compounds with remarkable physicochemical properties and thus qualifies them as NAPL candidates. This paper concerns the synthesis of ILs with octyl and butyl chains as well as different cations containing aromatic (imidazolium, pyridinium) and non-aromatic (piperidinum, pyrrolidinium) rings for CO2 absorption studies. The authors measured their respective toxicity levels on microalgae species, specifically, Scenedesmus quadricauda, Chlorella vulgaris and Botryococcus braunii. Results revealed that octyl-based ILs were more toxic than butyl-based analogues. Such was the case for bmim-PF6 at double saturation with an absorbance of 0.11, compared to Omim-PF6 at 0.17, bmim-NTf2 at 0.02, and Omim-NTf2 at 0.14, respectively. CO2 uptake results for ILs bearing octyl-based chains compared to the butyl analog were 54% (nCO2/nIL) (i.e., moles of CO2 moles of IL) and 38% (nCO2/nIL), respectively. Conclusively, 1-butyl-1-methylpiperidinium absorbed 13% (nCO2/nIL) and appeared the least toxic, having an absorbance of 0.25 at 688 nm (double saturation at 7 d) compared to 1-butyl-3-methylimidazolium, which showed the highest toxicity with zero absorbance. Accordingly, these findings suggest that 1-butyl-1-methylpiperidinium is capable of transporting CO2 to a system containing green microalgae without causing significant harm; thus allowing its use in TPPBR technology. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. An integrated microalgal growth model and its application to optimize the biomass production of Scenedesmus sp. LX1 in open pond under the nutrient level of domestic secondary effluent.

    Science.gov (United States)

    Wu, Yin-Hu; Li, Xin; Yu, Yin; Hu, Hong-Ying; Zhang, Tian-Yuan; Li, Feng-Min

    2013-09-01

    Microalgal growth is the key to the coupled system of wastewater treatment and microalgal biomass production. In this study, Monod model, Droop model and Steele model were incorporated to obtain an integrated growth model describing the combined effects of nitrogen, phosphorus and light intensity on the growth rate of Scenedesmus sp. LX1. The model parameters were obtained via fitting experimental data to these classical models. Furthermore, the biomass production of Scenedesmus sp. LX1 in open pond under nutrient level of secondary effluent was analyzed based on the integrated model, predicting a maximal microalgal biomass production rate about 20 g m(-2) d(-1). In order to optimize the biomass production of open pond the microalgal biomass concentration, light intensity on the surface of open pond, total depth of culture medium and hydraulic retention time should be 500 g m(-3), 16,000 lx, 0.2 m and 5.2 d in the conditions of this study, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Determination of fatty acid methyl esters derived from algae Scenedesmus dimorphus biomass by GC-MS with one-step esterification of free fatty acids and transesterification of glycerolipids.

    Science.gov (United States)

    Avula, Satya Girish Chandra; Belovich, Joanne M; Xu, Yan

    2017-05-01

    Algae can synthesize, accumulate and store large amounts of lipids in its cells, which holds immense potential as a renewable source of biodiesel. In this work, we have developed and validated a GC-MS method for quantitation of fatty acids and glycerolipids in forms of fatty acid methyl esters derived from algae biomass. Algae Scenedesmus dimorphus dry mass was pulverized by mortar and pestle, then extracted by the modified Folch method and fractionated into free fatty acids and glycerolipids on aminopropyl solid-phase extraction cartridges. Fatty acid methyl esters were produced by an optimized one-step esterification of fatty acids and transesterification of glycerolipids with boron trichloride/methanol. The matrix effect, recoveries and stability of fatty acids and glycerolipids in algal matrix were first evaluated by spiking stable isotopes of pentadecanoic-2,2-d 2 acid and glyceryl tri(hexadecanoate-2,2-d 2 ) as surrogate analytes and tridecanoic-2,2-d 2 acid as internal standard into algal matrix prior to sample extraction. Later, the method was validated in terms of lower limits of quantitation, linear calibration ranges, intra- and inter-assay precision and accuracy using tridecanoic-2,2-d 2 acid as internal standard. The method developed has been applied to the quantitation of fatty acid methyl esters from free fatty acid and glycerolipid fractions of algae Scenedesmus dimorphus. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Control of cytokinin and auxin homeostasis in cyanobacteria and algae.

    Science.gov (United States)

    Žižková, Eva; Kubeš, Martin; Dobrev, Petre I; Přibyl, Pavel; Šimura, Jan; Zahajská, Lenka; Záveská Drábková, Lenka; Novák, Ondřej; Motyka, Václav

    2017-01-01

    The metabolism of cytokinins (CKs) and auxins in vascular plants is relatively well understood, but data concerning their metabolic pathways in non-vascular plants are still rather rare. With the aim of filling this gap, 20 representatives of taxonomically major lineages of cyanobacteria and algae from Cyanophyceae, Xanthophyceae, Eustigmatophyceae, Porphyridiophyceae, Chlorophyceae, Ulvophyceae, Trebouxiophyceae, Zygnematophyceae and Klebsormidiophyceae were analysed for endogenous profiles of CKs and auxins and some of them were used for studies of the metabolic fate of exogenously applied radiolabelled CK, [3H]trans-zeatin (transZ) and auxin ([3H]indole-3-acetic acid (IAA)), and the dynamics of endogenous CK and auxin pools during algal growth and cell division. Quantification of phytohormone levels was performed by high-performance or ultrahigh-performance liquid chromatography-electrospray tandem mass spectrometry (HPLC-MS/MS, UHPLC-MS/MS). The dynamics of exogenously applied [3H]transZ and [3H]IAA in cell cultures were monitored by HPLC with on-line radioactivity detection. The comprehensive screen of selected cyanobacteria and algae for endogenous CKs revealed a predominance of bioactive and phosphate CK forms while O- and N-glucosides evidently did not contribute greatly to the total CK pool. The abundance of cis-zeatin-type CKs and occurrence of CK 2-methylthio derivatives pointed to the tRNA pathway as a substantial source of CKs. The importance of the tRNA biosynthetic pathway was proved by the detection of tRNA-bound CKs during the course of Scenedesmus obliquus growth. Among auxins, free IAA and its oxidation catabolite 2-oxindole-3-acetic acid represented the prevailing endogenous forms. After treatment with [3H]IAA, IAA-aspartate and indole-3-acetyl-1-glucosyl ester were detected as major auxin metabolites. Moreover, different dynamics of endogenous CKs and auxin profiles during S. obliquus culture clearly demonstrated diverse roles of both

  6. Increase of chromium tolerance in Scenedesmus acutus after sulfur starvation: Chromium uptake and compartmentalization in two strains with different sensitivities to Cr(VI).

    Science.gov (United States)

    Marieschi, M; Gorbi, G; Zanni, C; Sardella, A; Torelli, A

    2015-10-01

    In photosynthetic organisms sulfate constitutes the main sulfur source for the biosynthesis of GSH and its precursor Cys. Hence, sulfur availability can modulate the capacity to cope with environmental stresses, a phenomenon known as SIR/SED (Sulfur Induced Resistance or Sulfur Enhanced Defence). Since chromate may compete for sulfate transport into the cells, in this study chromium accumulation and tolerance were investigated in relation to sulfur availability in two strains of the unicellular green alga Scenedesmus acutus with different Cr-sensitivities. Paradoxically, sulfur deprivation has been demonstrated to induce a transient increase of Cr-tolerance in both strains. Sulfur deprivation is known to enhance the sulfate uptake/assimilation pathway leading to important consequences on Cr-tolerance: (i) reduced chromate uptake due to the induction of high affinity sulfate transporters (ii) higher production of cysteine and GSH which can play a role both through the formation of unsoluble complexes and their sequestration in inert compartments. To investigate the role of the above mentioned mechanisms, Cr accumulation in total cells and in different cell compartments (cell wall, membranes, soluble and miscellaneous fractions) was analyzed in both sulfur-starved and unstarved cells. Both strains mainly accumulated chromium in the soluble fraction, but the uptake was higher in the wild-type. In this type a short period of sulfur starvation before Cr(VI) treatment lowered chromium accumulation to the level observed in the unstarved Cr-tolerant strain, in which Cr uptake seems instead less influenced by S-starvation, since no significant decrease was observed. The increase in Cr-tolerance following S-starvation seems thus to rely on different mechanisms in the two strains, suggesting the induction of a mechanism constitutively active in the Cr-tolerant strain, maybe a high affinity sulfate transporter also in the wild-type. Changes observed in the cell wall and

  7. Polissacarídeos sulfatados isolados das clorofíceas Caulerpa racemosa e Caulerpa cupressoides – extração, fracionamento e atividade anticoagulante =Sulfated polysaccharides isolated from Caulerpa racemosa and Caulerpa cupressoides (Chlorophyceaes – extraction, fractionation and anticoagulant activity

    Directory of Open Access Journals (Sweden)

    José Ariévilo Gurgel Rodrigues

    2010-04-01

    Full Text Available A incidência de doenças cardiovasculares e os efeitos adversos da heparinoterapia têm motivado a busca por novos agentes terapêuticos e os polissacarídeos sulfatados (PS de algas marinhas têm sido reportados como fontes alternativas para tal. Objetivou-se avaliar o potencial anticoagulante dos PS totais (PST isolados e fracionados das clorofíceas Caulerpa racemosa e Caulerpa cupressoides. Inicialmente, os PST foram extraídos com papaína em tampão acetato desódio 0,1 M (pH 5,0 contendo cisteína 5 mM e EDTA 5 mM, seguidos de fracionamento em coluna de troca iônica de DEAE-celulose com gradiente de NaCl. As frações obtidas foram analisadas por eletroforese em gel de agarose a 0,5% e a atividade anticoagulante, mensurada pelo tempo de tromboplastina parcial ativada (TTPA, usando-se plasma humano normal e comparada a uma curva-padrão de heparina (193 UI mg-1. Verificaram-se semelhantes perfiscromatográficos entre os PS de ambas as espécies, porém com padrões de mobilidades distintas quando as frações foram comparadas por eletroforese. Os PS modificaram o TTPA, cujas atividades anticoagulantes foram de apenas 21,23 e 24,36 UI mg-1, quando eluídos com 0,75 M de sal para C. racemosa e C. cupressoides, respectivamente. Portanto, PS anticoagulantes isolados dasclorofíceas C. racemosa e C. cupressoides resultaram em efeitos anticoagulantes inferiores aos da heparina. Estudos comparativos dessas moléculas também são sugeridos como ferramentas auxiliares na identificação de algas do mesmo gênero.The incidence of cardiovascular diseases and adverse effects from heparintherapy have led to a search for new therapeutic agents, and the sulfated polysaccharides (SP of seaweeds have been reported as alternative sources. The aim of this work was to evaluate the anticoagulant potential of total SP (TSP isolated and fractionated from Caulerpa racemosa and Caulerpa cupressoides (Chlorophyceaes. Initially, the TSP were extracted with papain

  8. integrated vertical photobioreactor system for carbon dioxide

    African Journals Online (AJOL)

    Astri Nugroho

    2013-07-02

    Jul 2, 2013 ... Abstract. A vertical photobioreactor containing the microalgae Scenedesmus obliquus is a highly efficient system for converting carbon dioxide (CO2) into biomass. The use of photobioreactor for CO2 mitigation has been explored using microalgae as photosynthetic microorganism. The growth rate (μ, h-1) ...

  9. Dynamics of photosynthetic activity of cyanobacteria after gut ...

    African Journals Online (AJOL)

    The mainly stimulated eukaryotic algae species were Fragilariaceae and Scenedesmus obliquus by microscopy. Our results provide experimental evidence that Microcystis is damaged by crucian carp and goldfish digestion. That may be useful as a complementary method for combating cyanobacterial blooms and utilizing ...

  10. International Hydrogenase Conference (7th) Held at the University of Reading on August 24th to 29th 2004.

    Science.gov (United States)

    2004-08-19

    only hydrogenase and for the heterologous over-expressions of the Chlamydomonas reinhardtii and Scenedesmus obliquus HydAl Fe-only hydrogenases. The...unfolding the enzyme with urea in the presence mercaptoethanol [1 ]. The purified cofactor contained iron which remained bound even in the presence of 50

  11. Development of Pattern Recognition Techniques for the Evaluation of Toxicant Impacts to Multispecies Systems.

    Science.gov (United States)

    1992-06-22

    Chlorella vulgaris , Lyngbya sp. Nitzschia kutzigiana (Diatom 216), Scenedesmus obliquus, Selenastrum capricornutum, Stigeoclonium sp., and Ulothrix sp...world. Large amounts are used by the military and airline carriers. As with most petroleum products, Jet-A consists of numerous constituents with...Olympia, WA. Toxicity evaluation of petroleum mixtures. SETAC Microcosm Workshop. Design and data analysis of microcosms for pesticide evaluations

  12. Integrated Vertical Photobioreactor System for Carbon Dioxide ...

    African Journals Online (AJOL)

    A vertical photobioreactor containing the microalgae Scenedesmus obliquus is a highly efficient system for converting carbon dioxide (CO2) into biomass. The use of photobioreactor for CO2 mitigation has been explored using microalgae as photosynthetic microorganism. The growth rate (m, h-1) were 0.03; 0.13; 0.20; 0.09 ...

  13. Nutritional And Taste Characteristics Of Algae

    Science.gov (United States)

    Karel, M.; Nakhost, Z.

    1992-01-01

    Report describes investigation of chemical composition of blue-green algae Synechococcus 6311, as well as preparation of protein isolate from green alga Scenedesmus obliquus and incorporation into variety of food products evaluated for taste. Part of program to investigate growth of microalgae aboard spacecraft for use as food.

  14. Evaluation of the measurement of Cu(II) bioavailability in complex aqueous media using a hollow-fiber supported liquid membrane device (HFSLM) and two microalgae species (Pseudokirchneriella subcapitata and Scenedesmus acutus).

    Science.gov (United States)

    Rodríguez-Morales, Erik A; Rodríguez de San Miguel, Eduardo; de Gyves, Josefina

    2015-11-01

    The environmental bioavailability of copper was determined using a hollow-fiber supported liquid membrane (HFSLM) device as a chemical surrogate and two microalgae species (Scenedesmus acutus and Pseudokirchneriella subcapitata). Several experimental conditions were studied: pH, the presence of organic matter, inorganic anions, and concomitant cations. The results indicated a strong relationship between the response given by the HFSLM and the microalgae species with free copper concentrations measured by an ion selective electrode (ISE), in accordance with the free-ion activity model (FIAM). A significant positive correlation was evident when comparing the bioavailability results measured by the HFSLM and the S. acutus microalga species, showing that the synthetic device may emulate biological uptake and, consequently, be used as a chemical test for bioavailability measurements using this alga as a biological reference. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Conteúdo lipídico e composição de ácidos graxos de microalgas expostas aos gases CO2, SO2 e NO Lipid content and fatty acids composition variation of microalgae exposed to CO2, SO2 and NO

    Directory of Open Access Journals (Sweden)

    Elisangela Martha Radmann

    2008-01-01

    Full Text Available The objective of the present work was to verify the lipid content and the fatty acid composition of the microalgae Spirulina sp., Scenedesmus obliquus, Synechococcus nidulans and Chlorella vulgaris cultivated in a medium containing CO2, SO2 and NO. The microalga Scenedesmus obliquus presented the highest lipid content (6.18%. For the other microalgae the lipid content ranged from 4.56 to 5.97%. The major monounsaturated fatty acids content was 66.01% for S. obliquus. The PUFA were obtained in major amount by the microalgae Spirulina sp. (29.37% and S. nidulans (29.54%. The palmitoleic acid was in larger amount, with 41.02% concentration (Spirulina sp..

  16. In silico modelling for predicting the cationic hydrophobicity and cytotoxicity of ionic liquids towards the Leukemia rat cell line, Vibrio fischeri and Scenedesmus vacuolatus based on molecular interaction potentials of ions.

    Science.gov (United States)

    Cho, C-W; Ranke, J; Arning, J; Thöming, J; Preiss, U; Jungnickel, C; Diedenhofen, M; Krossing, I; Stolte, S

    2013-10-01

    In this study we present prediction models for estimating in silico the cationic hydrophobicity and the cytotoxicity (log [1/EC50]) of ionic liquids (ILs) towards the Leukemia rat cell line (IPC-81), the marine bacterium Vibrio fischeri and the limnic green algae Scenedesmus vacuolatus using linear free energy relationship (LFER) descriptors computed by COSMO calculations. The LFER descriptors used for the prediction model (i.e. excess molar refraction (E), dipolarity/polarizability (S), hydrogen-bonding acidity (A), hydrogen-bonding basicity (B) and McGowan volume (V)) were calculated using sub-descriptors (sig2, sig3, HBD3, HBA4, MR, and volume) derived from COSMO-RS, COSMO and OBPROP. With the combination of two solute descriptors (B, V) of the cation we were able to predict cationic hydrophobicity values (log ko ) with r (2) = 0.987 and standard error (SE) = 0.139 log units. By using the calculated log k o values, we were able to deduce a linear toxicity prediction model. In the second prediction study for the cytotoxicity of ILs, analysis of descriptor sensitivity helped us to determine that the McGowan volume (V) terms of the cation was the most important predictor of cytotoxicity and to simplify prediction models for cytotoxicity of ILs towards the IPC-81 (r (2) of 0.778, SE of 0.450 log units), Vibrio fischeri (r (2) of 0.762, SE of 0.529 log units) and Scenedesmus vacuolatus (r (2) of 0.776, SE of 0.825 log units). The robustness and predictivity of the two models for IPC-81 and Vibrio fischeri were checked by comparing the calculated SE and r (2) (coefficient of determination) values of the test set.

  17. Detection of green algae (Chlorophyceae) for the diagnosis of drowning.

    Science.gov (United States)

    Yoshimura, S; Yoshida, M; Okii, Y; Tokiyasu, T; Watabiki, T; Akane, A

    1995-01-01

    The plankton test (generally, diatom test) is one of the methods available to diagnose the cause of death of submerged bodies. The solubilization method using tissue solubilizer Soluene-350 was used in this study to detect not only diatoms but also green algae, based on the fact that the solubilizer does not digest the cell walls of green algae which are made from cellulose. Detection of green algae from organs of submerged cadavers is very informative to determine drowning in fresh water, and also in cases where only few diatoms are detected in the organs.

  18. Polissacarídeos sulfatados isolados das clorofíceas Caulerpa racemosa e Caulerpa cupressoides – extração, fracionamento e atividade anticoagulante - doi: 10.4025/actascibiolsci.v32i2.5923 Sulfated polysaccharides isolated from Caulerpa racemosa and Caulerpa cupressoides (Chlorophyceaes – extraction, fractionation and anticoagulant activity - doi: 10.4025/actascibiolsci.v32i2.5923

    Directory of Open Access Journals (Sweden)

    Norma Maria Barros Benevides

    2010-05-01

    Full Text Available A incidência de doenças cardiovasculares e os efeitos adversos da heparinoterapia têm motivado a busca por novos agentes terapêuticos e os polissacarídeos sulfatados (PS de algas marinhas têm sido reportados como fontes alternativas para tal. Objetivou-se avaliar o potencial anticoagulante dos PS totais (PST isolados e fracionados das clorofíceas Caulerpa racemosa e Caulerpa cupressoides. Inicialmente, os PST foram extraídos com papaína em tampão acetato de sódio 0,1 M (pH 5,0 contendo cisteína 5 mM e EDTA 5 mM, seguidos de fracionamento em coluna de troca iônica de DEAE-celulose com gradiente de NaCl. As frações obtidas foram analisadas por eletroforese em gel de agarose a 0,5% e a atividade anticoagulante, mensurada pelo tempo de tromboplastina parcial ativada (TTPA, usando-se plasma humano normal e comparada a uma curva-padrão de heparina (193 UI mg-1. Verificaram-se semelhantes perfis cromatográficos entre os PS de ambas as espécies, porém com padrões de mobilidades distintas quando as frações foram comparadas por eletroforese. Os PS modificaram o TTPA, cujas atividades anticoagulantes foram de apenas 21,23 e 24,36 UI mg-1, quando eluídos com 0,75 M de sal para C. racemosa e C. cupressoides, respectivamente. Portanto, PS anticoagulantes isolados das clorofíceas C. racemosa e C. cupressoides resultaram em efeitos anticoagulantes inferiores aos da heparina. Estudos comparativos dessas moléculas também são sugeridos como ferramentas auxiliares na identificação de algas do mesmo gênero.The incidence of cardiovascular diseases and adverse effects from heparintherapy have led to a search for new therapeutic agents, and the sulfated polysaccharides (SP of seaweeds have been reported as alternative sources. The aim of this work was to evaluate the anticoagulant potential of total SP (TSP isolated and fractionated from Caulerpa racemosa and Caulerpa cupressoides (Chlorophyceaes. Initially, the TSP were extracted with

  19. The chloroplast genome sequence of the green alga Leptosira terrestris: multiple losses of the inverted repeat and extensive genome rearrangements within the Trebouxiophyceae

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    Turmel Monique

    2007-07-01

    Full Text Available Abstract Background In the Chlorophyta – the green algal phylum comprising the classes Prasinophyceae, Ulvophyceae, Trebouxiophyceae and Chlorophyceae – the chloroplast genome displays a highly variable architecture. While chlorophycean chloroplast DNAs (cpDNAs deviate considerably from the ancestral pattern described for the prasinophyte Nephroselmis olivacea, the degree of remodelling sustained by the two ulvophyte cpDNAs completely sequenced to date is intermediate relative to those observed for chlorophycean and trebouxiophyte cpDNAs. Chlorella vulgaris (Chlorellales is currently the only photosynthetic trebouxiophyte whose complete cpDNA sequence has been reported. To gain insights into the evolutionary trends of the chloroplast genome in the Trebouxiophyceae, we sequenced cpDNA from the filamentous alga Leptosira terrestris (Ctenocladales. Results The 195,081-bp Leptosira chloroplast genome resembles the 150,613-bp Chlorella genome in lacking a large inverted repeat (IR but differs greatly in gene order. Six of the conserved genes present in Chlorella cpDNA are missing from the Leptosira gene repertoire. The 106 conserved genes, four introns and 11 free standing open reading frames (ORFs account for 48.3% of the genome sequence. This is the lowest gene density yet observed among chlorophyte cpDNAs. Contrary to the situation in Chlorella but similar to that in the chlorophycean Scenedesmus obliquus, the gene distribution is highly biased over the two DNA strands in Leptosira. Nine genes, compared to only three in Chlorella, have significantly expanded coding regions relative to their homologues in ancestral-type green algal cpDNAs. As observed in chlorophycean genomes, the rpoB gene is fragmented into two ORFs. Short repeats account for 5.1% of the Leptosira genome sequence and are present mainly in intergenic regions. Conclusion Our results highlight the great plasticity of the chloroplast genome in the Trebouxiophyceae and indicate

  20. Importance of algae as a potential source of biofuel.

    Science.gov (United States)

    Singh, A K; Singh, M P

    2014-12-24

    Algae have a great potential source of biofuels and also have unique importance to reduce gaseous emissions, greenhouse gases, climatic changes, global warming receding of glaciers, rising sea levels and loss of biodiversity. The microalgae, like Scenedesmus obliquus, Neochloris oleabundans, Nannochloropsis sp., Chlorella emersonii, and Dunaliella tertiolecta have high oil content. Among the known algae, Scenedesmus obliquus is one of the most potential sources for biodiesel as it has adequate fatty acid (linolenic acid) and other polyunsaturated fatty acids. Bio—ethanol is already in the market of United States of America and Europe as an additive in gasoline. Bio—hydrogen is the cleanest biofuel and extensive efforts are going on to bring it to market at economical price. This review highlights recent development and progress in the field of algae as a potential source of biofuel.

  1. Potential utilization of algal protein concentrate as a food ingredient in space habitats

    Science.gov (United States)

    Nakhost, Z.; Karel, M.

    1989-01-01

    Green alga Scenedesmus obliquus was studied as one of the potential sources of macronutrients in a space habitat. Algal protein concentrate (70.5% protein) was incorporated into a variety of food products such as bran muffins, fettuccine (spinach noodle imitation) and chocolate chip cookies. Food products containing 20 to 40% of incorporated algal proteins were considered. In the sensory analysis the greenish color of the bran muffins and cookies was not found to be objectional. The mild spinachy flavor (algae flavor) was less detectable in chocolate chip cookies than in bran muffins. The color and taste of the algae noodles were found to be pleasant and compared well with commercially available spinach noodles. Commercially available spray-dried Spirulina algae was also incorporated so the products can be compared with those containing Scenedesmus obliquus concentrate. Food products containing commercial algae had a dark green color and a "burnt after taste" and were less acceptable to the panelists.

  2. Potential for utilization of algal biomass for components of the diet in CELSS

    Science.gov (United States)

    Kamarei, A. R.; Nakhost, Z.; Karel, M.

    1986-01-01

    The major nutritional components of the green algae (Scenedesmus obliquus) grown in a Constant Cell Density Apparatus were determined. Suitable methodology to prepare proteins from which three major undesirable components of these cells (i.e., cell walls, nucleic acids, and pigments) were either removed or substantially reduced was developed. Results showed that processing of green algae to protein isolate enhances is potential nutritional and organoleptic acceptability as a diet component in controlled Ecological Life Support System.

  3. Utilization of non-conventional systems for conversion of biomass to food components: Potential for utilization of algae in engineered foods

    Science.gov (United States)

    Karel, M.; Kamarei, A. R.; Nakhost, Z.

    1985-01-01

    The major nutritional components of the green algae (Scenedesmus obliquus) grown in a Constant Cell density Apparatus were determined. Suitable methodology to prepare proteins from which three major undesirable components of these cells (i.e., cell walls, nucleic acids, and pigments) were either removed or substantially reduced was developed. Results showed that processing of green algae to protein isolate enhances its potential nutritional and organoleptic acceptability as a diet component in a Controlled Ecological Life Support System.

  4. Algal culture studies related to a Closed Ecological Life Support System (CELSS)

    Science.gov (United States)

    Radmer, R.; Behrens, P.; Fernandez, E.; Ollinger, O.; Howell, C.; Venables, A.; Huggins, D.; Gladue, R.

    1984-01-01

    In many respects, algae would be the ideal plant component for a biologically based controlled life support system, since they are eminently suited to the closely coupled functions of atmosphere regeneration and food production. Scenedesmus obliquus and Spirulina platensis were grown in three continuous culture apparatuses. Culture vessels their operation and relative merits are described. Both light and nitrogen utilization efficiency are examined. Long term culture issues are detailed and a discussion of a plasmid search in Spirulina is included.

  5. Evidence for the Participation of the Reductive Pentose Phosphate Cycle in Photoreduction and the Oxyhydrogen Reaction 1

    Science.gov (United States)

    Russell, George K.; Gibbs, Martin

    1968-01-01

    The assimilation of 14C-sodium bicarbonate has been measured in Scenedesmus obliquus as 1) photosynthesis, 2) photoreduction (light dependent incorporation of carbon dioxide by hydrogen adapted cells under conditions where photosynthesis is inoperative), and 3) the oxyhydrogen reaction (dark assimilation of carbon dioxide by hydrogen adapted cells in an atmosphere of hydrogen and 1% oxygen). Degradation of the glucose formed in each of these reactions using the Leuconostoc technique establishes the participation of the reductive pentose phosphate cycle. PMID:16656821

  6. A new lipid-rich microalga Scenedesmus sp. strain R-16 isolated using Nile red staining: effects of carbon and nitrogen sources and initial pH on the biomass and lipid production

    Science.gov (United States)

    2013-01-01

    Background Biodiesel production from oleaginous microalgae shows great potential as a promising alternative to conventional fossil fuels. Currently, most research focus on algal biomass production with autotrophic cultivation, but this cultivation strategy induces low biomass concentration and it is difficult to be used in large-scale algal biomass production. By contrast, heterotrophic algae allows higher growth rate and can accumulate higher lipid. However, the fast-growing and lipid-rich microalgae that can be cultivated in heterotrophic system for the industrial application of biodiesel production are still few. Traditional solvent extraction and gravimetric determination to detect the microalgal total lipid content is time-consuming and laborious, which has become a major limiting factor for selecting large number of algae specimens. Thus, it is critical to develop a rapid and efficient procedure for the screening of lipid-rich microalgae. Results A novel green microalga Scenedesmus sp. strain R-16 with high total lipid content was selected using the Nile red staining from eighty-eight isolates. Various carbon sources (fructose, glucose and acetate) and nitrogen sources (nitrate, urea, peptone and yeast extract) can be utilized for microalgal growth and lipid production, and the optimal carbon and nitrogen sources were glucose (10 g L-1) and nitrate (0.6 g L-1), respectively. Compared to autotrophic situation, the strain R-16 can grow well heterotrophically without light and the accumulated total lipid content and biomass reached 43.4% and 3.46 g L-1, respectively. In addition, nitrogen deficiency led to an accumulation of lipid and the total lipid content was as high as 52.6%, and it was worth noting that strain R-16 exhibited strong tolerance to high glucose (up to 100 g L-1) and a wide range of pH (4.0-11.0). Conclusions The newly developed ultrasonic-assisted Nile red method proved to be an efficient isolation procedure and was successfully used in

  7. A new lipid-rich microalga Scenedesmus sp. strain R-16 isolated using Nile red staining: effects of carbon and nitrogen sources and initial pH on the biomass and lipid production.

    Science.gov (United States)

    Ren, Hong-Yu; Liu, Bing-Feng; Ma, Chao; Zhao, Lei; Ren, Nan-Qi

    2013-10-06

    Biodiesel production from oleaginous microalgae shows great potential as a promising alternative to conventional fossil fuels. Currently, most research focus on algal biomass production with autotrophic cultivation, but this cultivation strategy induces low biomass concentration and it is difficult to be used in large-scale algal biomass production. By contrast, heterotrophic algae allows higher growth rate and can accumulate higher lipid. However, the fast-growing and lipid-rich microalgae that can be cultivated in heterotrophic system for the industrial application of biodiesel production are still few. Traditional solvent extraction and gravimetric determination to detect the microalgal total lipid content is time-consuming and laborious, which has become a major limiting factor for selecting large number of algae specimens. Thus, it is critical to develop a rapid and efficient procedure for the screening of lipid-rich microalgae. A novel green microalga Scenedesmus sp. strain R-16 with high total lipid content was selected using the Nile red staining from eighty-eight isolates. Various carbon sources (fructose, glucose and acetate) and nitrogen sources (nitrate, urea, peptone and yeast extract) can be utilized for microalgal growth and lipid production, and the optimal carbon and nitrogen sources were glucose (10 g L-1) and nitrate (0.6 g L-1), respectively. Compared to autotrophic situation, the strain R-16 can grow well heterotrophically without light and the accumulated total lipid content and biomass reached 43.4% and 3.46 g L-1, respectively. In addition, nitrogen deficiency led to an accumulation of lipid and the total lipid content was as high as 52.6%, and it was worth noting that strain R-16 exhibited strong tolerance to high glucose (up to 100 g L-1) and a wide range of pH (4.0-11.0). The newly developed ultrasonic-assisted Nile red method proved to be an efficient isolation procedure and was successfully used in the selection of oleaginous

  8. Effects of artemisinin sustained-release granules on mixed alga growth and microcystins production and release.

    Science.gov (United States)

    Ni, Lixiao; Li, Danye; Hu, Shuzhen; Wang, Peifang; Li, Shiyin; Li, Yiping; Li, Yong; Acharya, Kumud

    2015-12-01

    To safely and effectively apply artemisinin sustained-release granules to control and prevent algal water-blooms, the effects of artemisinin and its sustained-release granules on freshwater alga (Scenedesmus obliquus (S. obliquus) and Microcystis aeruginosa (M. aeruginosa)), as well as the production and release of microcystins (MCs) were studied. The results showed that artemisinin sustained-release granules inhibited the growth of M. aeruginosa (above 95% IR) and S. obliquus (about 90% IR), with M. aeruginosa more sensitive. The artemisinin sustained-release granules had a longer inhibition effect on growth of pure algae and algal coexistence than direct artemisinin dosing. The artemisinin sustained-release granules could decrease the production and release of algal toxins due to the continued stress of artemisinin released from artemisinin sustained-release granules. There was no increase in the total amount of MC-LR in the algal cell culture medium.

  9. SIMULATION OF MICROALGAL GROWTH IN A CONTINUOUS PHOTOBIOREACTOR WITH SEDIMENTATION AND PARTIAL BIOMASS RECYCLING

    Directory of Open Access Journals (Sweden)

    C. E. de Farias Silva

    Full Text Available Abstract Microalgae are considered as promising feedstocks for the third generation of biofuels. They are autotrophic organisms with high growth rate and can stock an enormous quantity of lipids (about 20 - 40% of their dried cellular weight. This work was aimed at studying the cultivation of Scenedesmus obliquus in a two-stage system composed of a photobioreactor and a settler to concentrate and partially recycle the biomass as a way to enhance the microalgae cellular productivity. It was attempted to specify by simulation and experimental data a relationship between the recycling rate, kinetic parameters of microalgal growth and photobioreactor operating conditions. Scenedesmus obliquus cells were cultivated in a lab-scale flat-plate reactor, homogenized by aeration, and running in continuous flow with a residence time of 1.66 day. Experimental data for the microalgal growth were used in a semi-empirical simulation model. The best results were obtained for Fw=0.2FI, when R = 1 and kd = 0 and 0.05 day-1, with the biomass production in the reactor varying between 8 g L -1 and 14 g L-1, respectively. The mathematical model fitted to the microalgal growth experimental data was appropriate for predicting the efficiency of the reactor in producing Scenedesmus obliquus cells, establishing a relation between cellular productivity and the minimum recycling rate that must be used in the system.

  10. Extraction and anticoagulant activity of sulfated polysaccharides from Caulerpa cupressoides var. lycopodium (Vahl C. Agardh (Chlorophyceae = Extração e atividade anticoagulante dos polissacarídeos sulfatados da clorofícea Caulerpa cupressoides var. lycopodium (Vahl C. Agardh = Extração e atividade anticoagulante dos polissacarídeos sulfatados da clorofícea Caulerpa cupressoides var. lycopodium (Vahl C. Agardh.

    Directory of Open Access Journals (Sweden)

    José Ariévilo Gurgel Rodrigues

    2011-04-01

    Full Text Available The reportedly low standard quality of heparin (HEP for use in cardiac surgeries has led to concern in the Brazilian and international markets. Sulfated polysaccharides (SPs from seaweeds have been regarded as promising substitutes for HEP. The aim of this study was to sequentially extract total SPs (TSPs from Caulerpa cupressoides (Chlorophyceae with papain in 100 mM sodium acetate buffer (pH 5.0 containing 5 mM cysteine and 5 mM EDTA, followed byfractionation by ion-exchange chromatography (DEAE-cellulose, and then evaluate the anticoagulant potential of SP fractions by activated partial thromboplastin time (APTT using normal human plasma and compare it to standard HEP (193 IU mg-1. The obtained fractions were chemically characterized by chemical composition and agarose gel electrophoresis. The yield was 4.61%, and three fractions of SP (F I, F II and F III eluted with 0.50, 0.75 and 1.00 M of NaCl,respectively, were observed on chromatography profiles; however, differences in charge densities patterns and degree of resolution among them were revealed by electrophoresis. SPs were capable of modifying APTT only in fractions eluted with 0.75 M of NaCl, whose activities were 23.37 and 25.76 IU mg-1, respectively, and the charge density was prerequisite to activity. Therefore, C. cupressoides is a source of SPs possessing low anticoagulant potential compared to HEP.O baixo padrão de qualidade outrora declarado da heparina (HEP para o uso em cirurgias cardíacas tem levado preocupação nos mercados nacional e internacional. Os polissacarídeos sulfatados (PSs de algasmarinhas têm sido considerados como promissores substitutos para HEP. Objetivou-se a extrair sequencialmente PSs totais (PSTs da clorofícea Caulerpa cupressoides com papaína em tampão acetato de sódio 100 mM (pH 5,0 contendo cisteína 5 mM e EDTA 5 mM, fracionar por cromatografia de troca iônica (DEAE-celulose e avaliar o potencial anticoagulante das frações de PS por meio do

  11. Chlorococcales (Algee: Chlorophyceae found in aquatic environments of the Colombian Amazon basin Chlorococcales (Algee: Chlorophyceae found in aquatic environments of the Colombian Amazon basin

    Directory of Open Access Journals (Sweden)

    Núñez Avellaneda Marcela

    1998-06-01

    Full Text Available Ten taxa of algae belonging to the order Chlorococcales are recorded for the first time from the Colombian Amazon basin. Two of these, Nephrocytium limneticum and Sorastrum americanum var. americanum, are recorded for the first time in Colombia.Se registran por primera vez para la Amazonia colombiana 10 taxones de Chlorococcales del fitoplancton y ticoplancton encontrados en algunos lagos del río Amazonas y del río Cotuhé, afluente del río Putumayo. Nephrocytium limneticum y Sorastrum americanum varo americanum son primeros registros para Colombia.

  12. Efeitos da eletroestimulação do músculo vasto medial oblíquo em portadores de síndrome da dor patelofemoral: uma análise eletromiográfica Effects of electrical stimulation of vastus medialis obliquus muscle in patients with patellofemoral pain syndrome: an electromyographic analysis

    Directory of Open Access Journals (Sweden)

    Fabiana R. Garcia

    2010-12-01

    Full Text Available CONTEXTUALIZAÇÃO: O uso da eletromiografia de superfície (EMG-S tem sido considerado como instrumento de avaliação quantitativa na síndrome da dor patelofemoral (SDPF. Tratamentos conservadores objetivam melhorar o alinhamento patelar, e a estimulação elétrica do músculo vasto medial oblíquo (VMO tem sido considerada por ser seletiva e não causar irritação articular. OBJETIVO: Verificar o efeito de um programa de fortalecimento muscular com estimulação elétrica do VMO na SDPF por meio da capacidade de avaliação da EMG-S. MÉTODOS: Participaram deste estudo 10 mulheres jovens (idade: 23,1±4,9 anos; massa corporal: 66,8±14,0 kg; estatura: 1,63±6,9 cm; IMC: 25,1±5,6 kg/m² com SDPF unilateral, as quais realizaram o teste funcional de subir degrau para captação da atividade eletromiográfica dos músculos VMO e vasto lateral (VL, antes e após um programa de estimulação elétrica do VMO. A eletroestimulação foi realizada três vezes por semana, durante seis semanas. Foram consideradas, para análise entre VMO e VL, as variáveis razão do tempo do início até o pico de ativação, razão da integral do sinal (teste t para amostras dependentes e diferença de início de ativação (teste de Wilcoxon, com n��vel de significância de pBACKGROUND: The use of surface electromyography (SEMG has been considered a tool for quantitative assessment of patellofemoral pain syndrome (PFPS. Conservative treatments aim to improve patellar alignment, and electrical stimulation of the vastus medialis obliquus (VMO muscle has been considered effective because it is selective and does not cause joint irritation. OBJECTIVE: This study aims to investigate the efficiency of a muscle strengthening program with electrical stimulation of the VMO muscle in PFPS by SEMG. METHODS: A group of ten young women (age: 23.1±4.9 years; body mass: 66.8±14.0 kg; height: 1.63±6.9 cm; BMI: 25.1±5.6 kg/m² with unilateral PFPS participated in the

  13. [Acute Toxic Effects of Bromate on Aquatic Organisms].

    Science.gov (United States)

    Wang, Zhi-wei; Liu, Dong-mei; Zhang, Wen-juan; Cui, Fu-yi

    2016-02-15

    Acute toxic effects of potassium bromate, sodium bromate and potassium bromide on luminescent bacteria, water flea, green alga and zebrafish were studied using standard toxic testing methods. The results showed that the pollutants had no effect on the luminous intensity of luminescent bacteria. The 96 h EC5. of potassium bromate on Scenedesmus obliquus was 738.18 mg x L(-1), 48 h EC50 on Daphnia magna and Moina was 154.01 mg x L(-1) was 161.80 mg x L(-1), while 48 h LC50 was 198 52 mg x L(-1), 175.68 mg x L(-1), and 96 h LC50 on zebrafish was 931.4 mg x L(-1). The 96 h EC50 of sodium bromate on Scenedesmus obliquus was 540.26 mg x L(-1), 48 h EC50 Daphnia magna and Moina was 127.90 mg x L(-1), 111.07 mg x L(-1), while 48 h LC50 was 161.80 mg x L(-1), 123.47 mg x L(-1), and 96 h LC50 on zebrafish was 1065.6 mg x L(-1). But the effects of potassium bromide on the above several kinds of aquatic organisms were far smaller than those of potassium bromate and sodium bromate. The toxic effects on test organisms were due to the impacts of bromate after the comparison of different pollutants, and the effects were more obvious with the increase of exposure time. The order of sensitivity to the toxic effects of bromate was Daphnia magna, Moina > Scenedesmus obliquus > zebrafish > Chlorella vulgaris, luminescent bacteria.

  14. Oleaginous Microalgae from Dairy Farm Wastewater for Biodiesel Production: Isolation, Characterization and Mass Cultivation.

    Science.gov (United States)

    Sun, Zheng; Fang, Xiao-Peng; Li, Xiao-Yang; Zhou, Zhi-Gang

    2018-02-01

    Producing biodiesel from microalgae grown in wastewater is environment-friendly and cost-effective. The present study investigated the algae found in wastewater of a local dairy farm for their potential as biodiesel feedstocks. Thirteen native algal strains were isolated. On the basis of morphology and 16S/18S rRNA gene sequences, one strain was identified to be a member of cyanobacteria, while other 12 strains belong to green algae. After screening, two Scenedesmus strains out of the 13 microalgae isolates demonstrated superiority in growth rate, lipid productivity, and sedimentation properties, and therefore were selected for further scale-up outdoor cultivation. Both Scenedesmus strains quickly adapted to the outdoor conditions, exhibiting reasonably good growth and strong anti-contamination capabilities. In flat-plate photobioreactors (PBRs), algal cells accumulated predominantly neutral lipids that accounted for over 60% of total lipids with almost 70% being triacylglycerol. In addition, Scenedesmus obliquus had a high content of monounsaturated fatty acids, of which the amount of oleic acid (C18:1) was up to 27.11%. Based on these findings, the dairy farm wastewater-isolated Scenedesmus strains represent promising sources of low-cost, high-quality oil for biofuel production.

  15. Delineating a New Heterothallic Species of Volvox (Volvocaceae, Chlorophyceae Using New Strains of "Volvox africanus".

    Directory of Open Access Journals (Sweden)

    Hisayoshi Nozaki

    Full Text Available The volvocine algae represent an excellent model lineage in which to study evolution of female and male genders based on comparative analyses of related species. Among these species, Volvox carteri has been extensively studied as a model of an oogamous and complex organism. However, it may have unique derived features that are not present in other species of Volvox. Therefore, information regarding the characteristics of sexual reproduction of other species of Volvox is also important. In 1971, Starr studied four types of sexuality in several global strains identified as Volvox africanus; however, further taxonomic studies of these strains have been lacking, and strains of three of the four sexual types are not available. Here, we studied the morphology, sexual reproduction, and taxonomy of two V. africanus-like species isolated recently from Lake Biwa, Japan. These two species were very similar to two sexual types described by Starr in 1971: one producing dioecious sexual spheroids in heterothallic strains and the other forming both male spheroids and monoecious spheroids in a single strain. The former species produced zygotes with a reticulate cell wall, whereas a smooth zygote wall was observed in the latter species as in V. africanus previously reported from various localities around the world. Our multigene phylogenetic analysis demonstrated that these are sister species to each other. However, the presence of a compensatory base change in the most conserved region of the secondary structure of nuclear ribosomal DNA internal transcribed spacer-2, hybrid inviability demonstrated by intercrossing experiments, and morphological differences in the density of abutment between the gelatinous material of adjacent cells (individual sheaths in the spheroid supported the recognition of the two species, V. africanus having a smooth zygote wall and V. reticuliferus Nozaki sp. nov. having a reticulate zygote wall.

  16. Spectroscopic investigation of ionizing-radiation tolerance of a Chlorophyceae green micro-alga

    Science.gov (United States)

    Farhi, E.; Rivasseau, C.; Gromova, M.; Compagnon, E.; Marzloff, V.; Ollivier, J.; Boisson, A. M.; Bligny, R.; Natali, F.; Russo, D.; Couté, A.

    2008-03-01

    Micro-organisms living in extreme environments are captivating in the peculiar survival processes they have developed. Deinococcus radiodurans is probably the most famous radio-resistant bacteria. Similarly, a specific ecosystem has grown in a research reactor storage pool, and has selected organisms which may sustain radiative stress. An original green micro-alga which was never studied for its high tolerance to radiations has been isolated. It is the only autotrophic eukaryote that develops in this pool, although contamination possibilities coming from outside are not unusual. Studying what could explain this irradiation tolerance is consequently very interesting. An integrative study of the effects of irradiation on the micro-algae physiology, metabolism, internal dynamics, and genomics was initiated. In the work presented here, micro-algae were stressed with irradiation doses up to 20 kGy (2 Mrad), and studied by means of nuclear magnetic resonance, looking for modifications in the metabolism, and on the IN13 neutron backscattering instrument at the ILL, looking for both dynamics and structural macromolecular changes in the cells.

  17. Spectroscopic investigation of ionizing-radiation tolerance of a Chlorophyceae green micro-alga

    Energy Technology Data Exchange (ETDEWEB)

    Farhi, E; Compagnon, E; Marzloff, V; Ollivier, J; Boisson, A M; Natali, F; Russo, D [Institut Laue-Langevin, BP 156, 38042 Grenoble cedex 9 (France); Rivasseau, C; Gromova, M; Bligny, R [CEA, Laboratoire de Physiologie Cellulaire Vegetale, 17 rue des Martyrs, 38054 Grenoble cedex 9 (France); Coute, A [Museum National d' Histoire Naturelle, Laboratoire de Cryptogamie, 2 rue Buffon, 75005 Paris (France)

    2008-03-12

    Micro-organisms living in extreme environments are captivating in the peculiar survival processes they have developed. Deinococcus radiodurans is probably the most famous radio-resistant bacteria. Similarly, a specific ecosystem has grown in a research reactor storage pool, and has selected organisms which may sustain radiative stress. An original green micro-alga which was never studied for its high tolerance to radiations has been isolated. It is the only autotrophic eukaryote that develops in this pool, although contamination possibilities coming from outside are not unusual. Studying what could explain this irradiation tolerance is consequently very interesting. An integrative study of the effects of irradiation on the micro-algae physiology, metabolism, internal dynamics, and genomics was initiated. In the work presented here, micro-algae were stressed with irradiation doses up to 20 kGy (2 Mrad), and studied by means of nuclear magnetic resonance, looking for modifications in the metabolism, and on the IN13 neutron backscattering instrument at the ILL, looking for both dynamics and structural macromolecular changes in the cells.

  18. Resistant biomacromolecules in five marine microalgae of the classes Eustigmatophyceae and Chlorophyceae: Geochemical implications

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Gelin, F.; Boogers, I.; Noordeloos, A.A.M.; Riegman, R.; Leeuw, J.W. de

    1997-01-01

    Non-hydrolysable macromolecular constituents (i.e. algaenans) were isolated from two out of seven marine microalgae investigated. Nannochloropsis salina and Nannochloropsis sp. from the class of Eustigmatophyceae produce highly aliphatic algaenans. Flash pyrolysis and chemical degradations with HI

  19. Image-based monitoring system for green algal Haematococcus pluvialis (Chlorophyceae) cells during culture.

    Science.gov (United States)

    Ohnuki, Shinsuke; Nogami, Satoru; Ota, Shuhei; Watanabe, Koichi; Kawano, Shigeyuki; Ohya, Yoshikazu

    2013-11-01

    The green microalga Haematococcus pluvialis accumulates the red pigment astaxanthin accompanied by morphological changes under stress conditions, including nutrient depletion, continuous light and high temperature. To investigate the physiological state of the algal cells, we developed the digital image-processing software called HaematoCalMorph. The software automatically outputs 25 single-cell measurements of cell morphology and pigments based on color, bright-field microscopic images. Compared with manual inspection, the output values of cell shape were reliable and reproducible. The estimated pigment content fits the values calculated by conventional methods. Using a random forests classifier, we were able to distinguish flagellated cells from immotile cells and detect their transient appearance in culture. By performing principal components analysis, we also successfully monitored time-dependent morphological and colorimetric changes in culture. Thus, combined with multivariate statistical techniques, the software proves useful for studying cellular responses to various conditions as well as for monitoring population dynamics in culture.

  20. [Carotenogenesis of five strains of the algae Dunaliella sp. (Chlorophyceae) isolated from Venezuelan hypersaline lagoons].

    Science.gov (United States)

    Guevara, Miguel; Lodeiros, César; Gómez, Olga; Lemus, Nathalie; Núñez, Paulino; Romero, Lolymar; Vásquez, Aléikar; Rosales, Néstor

    2005-01-01

    We evaluated discontinuous cultures (Algal medium at 0.5 mM of NaNO3, and 27% NaCI) of five strains of Dunaliella sp. isolated from Venezuelan hypersaline lagoons (Araya, Coche, Peonia, Cumaraguas. and Boca Chica) and one strain from a reference collection (Dunaliella salina, LB1644). Cultures were maintained to 25+/-1 degrees C, with constant aeration, photoperiod 12:12, and two light intensities (195 and 390 microE.m(-2).s(-1)) during 30 days. Cell count was recorded on a daily basis using a Neubaüer camera. Totals of chlorophyll a and carotenoids were measured at the end of the experiment. The largest cellular densities were measured during the smallest light intensities. The strain with the largest cellular density was isolated from Boca Chica (8 xl0(6) and 2.5 xl0(6) cel.ml(-1) a 390 and 195microE.m(-2).s(-1), respectively). The increment of light intensity produced a significant reduction of growth rates in all strains. Totals of carotenoids by volume were as large as 390 microE.m(-2).s(-1). Strains LB 1644, from Coche and Araya were those that produced the largest amount of carotenoids (38.4; 32.8 and 21.0 microg.ml(-1), respectively). Differences total carotenoids by cell between treatments were significant. The largest concentration was 390 microE.m(-2).s(-1). The strains LB 1644 and Coche produced the highest values of carotenes (137.14 and 106.06 pg.cel(-1), respectively). Differences in the relation carotenoid:chlorophyll a between the strains at various light intensities was significant. Strains LB1644 presented the largest value of the relation carotenoids:chlorophyll a (20:1) at 195 microE.m(-2).s(-1). No significant differences were detected in the strain Coche (15:1). All the other strains showed relations lower than one. Our results suggest that the strains of Coche and Araya show potential to be used in the biotechnology of carotenoids production.

  1. Descriptive and mechanistic toxicity of conazole fungicides using the model test alga Dunaliella tertiolecta (Chlorophyceae).

    Science.gov (United States)

    Baird, Thomas D; DeLorenzo, Marie E

    2010-06-01

    Conazole fungicides are commonly used to prevent fungal growth on turf grass and agricultural crops. As many of these sites are adjacent to coastal waterways and estuaries, there exists the potential for nontarget effects of runoff on marine organisms. This study reports 96 h EC(50) values for four selected conazole fungicides (triadimefon = 5.98 mg/L; triadimenol = 5.51 mg/L; propiconazole = 2.33 mg/L; hexaconazole = 0.91 mg/L) to the model test alga Dunaliella tertiolecta. We further investigated possible mechanisms of toxicity by examining sublethal effects of exposure on cell morphology, osmoregulatory function, and lipid composition. These mechanistic studies revealed that conazole exposure does not inhibit synthesis of the cell's glycerol osmolyte, but does result in an overall increase in cellular volume and total lipid content. Both fungi and chlorophytes rely on ergosterol to maintain membrane structure and fluidity, and we provide evidence that the sterol-inhibiting conazoles may interfere with ergosterol biosynthesis in the cell membrane of Dunaliella. These findings suggest that green algae may be especially susceptible to nontarget effects of sterol-inhibiting fungicides in marine systems. Published 2009 by Wiley Periodicals, Inc.

  2. A survey of Polytomella (Chlorophyceae, Chlorophyta) strains in public culture collections.

    Science.gov (United States)

    MacDonald, Shelley M; Lee, Robert W

    2016-08-01

    Polytomella is a genus of colorless green algae in the Reinhardtinia clade of the Chlamydomonadales, which has proven useful for a broad range of studies particularly those exploring the evolutionary loss of photosynthesis and mitochondrial genomics/biochemistry. Although 13 Polytomella strain accessions are currently available from public culture collections, the taxonomic status and redundancy of many of these strains is not clear because of possible mix-ups, deficient historical records, and incomplete molecular data. This study therefore considers previously available and/or new cox1 and mitochondrial DNA telomere sequences from all 13 Polytomella strain accessions. Among four of these, namely P. parva SAG 63-3, P. piriformis SAG 63-10, P. capuana SAG 63-5, and P. magna SAG 63-9, cox1 and mitochondrial telomere regions are both highly divergent between strains. All of the remaining nine Polytomella strain accessions have cox1 sequences that are identical to that of P. parva SAG 63-3 and although five of these have a mitochondrial telomere haplotype that is identical to that of P. parva SAG 63-3, the remaining four have one of three different haplotypes. Among the 10 strains with identical cox1 sequences, we suggest that three of the telomere haplotypes are associated with distinct geographical isolates of Polytomella and the fourth evolved from one of these isolates during 50 years of active culture. © 2016 Phycological Society of America.

  3. Species of Caulerpa (Chlorophyceae) collected on the International Indian Ocean Expedition

    NARCIS (Netherlands)

    Taylor, Wm. Randolph

    1967-01-01

    One of the major scientific efforts of the decade has been the International Indian Ocean Expedition of 1960—64, involving several institutions and ships and numerous scientists. With an oceanographic focus, not only physical and biological open sea oceanographic studies were carried on, but

  4. Cell types and their status in Chlamydomonas-like algae (Chlorophyceae on agar medium culture

    Directory of Open Access Journals (Sweden)

    M.М. Pavlovska

    2014-04-01

    Full Text Available The classification of cell types under agar culture was proposed. Six cell morphotypes were allocated. The statuses were identified depending on the reduction of monade attributes of cells. The variants of transition from one cell morphotype to another under dissolving mucilage were shown. The monade, cocciod, palmeloid and gloeocysta morphotypes approximately equally represented in all clades. The asterococcus and mucogleocysta morphotypes presented only in Reinhardtinia аnd Oogamochlamydinia clades. Any morphotype isn’t typical for all clades of Chlamydomonas-like algae at once. The most of morphotypes numbers (5 from 6 are presented in Reinhardtinia clade. This demonstrates the diversity of the Reinhardtinia clade species. There are only one morphotype presented in Polytominia and Monadinia clades. There are four morphotypes presented in Oogamochlamydinia clade, three – in Moewusinia, two morphotypes – in Chloromonadinia.

  5. A NEW SPECIES OF VOLVOX SECT. MERRILLOSPHAERA (VOLVOCACEAE, CHLOROPHYCEAE) FROM TEXAS1.

    Science.gov (United States)

    Nozaki, Hisayoshi; Coleman, Annette W

    2011-06-01

    Smith (1944) divided the familiar genus Volvox L. into four sections, placing seven species that lacked cytoplasmic bridges between adult cells in the section Merrillosphaera. Herein, we describe a new member of the section Merrillosphaera originating from Texas (USA): Volvox ovalis Pocock ex Nozaki et A. W. Coleman sp. nov. Asexual spheroids of V. ovalis are ovoid or elliptical, with a monolayer of 1,000-2,000 somatic cells that are not linked by cytoplasmic bridges, an expanded anterior region, and 8-12 gonidia in the posterior region. Visibly asymmetric cleavage divisions do not occur in V. ovalis embryos as they do Volvox carteri F. Stein, Volvox obversus (W. Shaw) Printz, and Volvox africanus G. S. West, so the gonidia of the next generation are not yet recognizable in V. ovalis embryos prior to inversion. Molecular phylogenetic analyses of the five chloroplast genes and the internal transcribed spacer (ITS) regions of nuclear rDNA indicated that V. ovalis is closely related to Volvox spermatosphaera Powers (Powers 1908, as "spermatosphara") and/or Volvox tertius Art. Mey.; however, V. ovalis can be distinguished from V. spermatosphaera by its larger gonidia, and from V. tertius by visible differences in gonidial chloroplast morphology. © 2011 Phycological Society of America.

  6. Lead (Pb heavy metal impacts in the green Ulva lactuca (Chlorophyceae marine algae

    Directory of Open Access Journals (Sweden)

    B. Saleh

    2016-05-01

    Full Text Available Toxicity of different lead (Pb (0, 2, 4 and 8 mg/L concentrations in the green Ulva lactuca (Chlorophyta marine algae at physiological level has been investigated 48 h after Pb treatment under laboratory conditions. Thalus algae damages followed Pb treatment as revealed by microscopy test showed that the 4 and 8 mg/L Pb caused morphological changes in cells viability; whereas, no effect observed at the lowest Pb applied concentration (2 mg/L. Data revealed that Pb stress caused reduction in most investigated physiological parameters i.e. Pigments content, osmotic potential and membrane stability index values. This decline in osmotic potential was significantly (p ≤ 0.001 different. Whereas, estimated electric conductivity (EC values increased significantly (p ≤ 0.001 as applied Pb concentration increased. The current study allowed somewhat to highlight and better understanding Pb impacts in U. lactuca algae. Thereby, the studied algae could be used as a useful bioindicator in Pb polluted ecosystems.

  7. Flow Cytometric Methods for Indirect Analysis and Quantification of Gametogenesis in Chlamydomonas reinhardtii (Chlorophyceae)

    Science.gov (United States)

    Tomkins, Joseph L.

    2016-01-01

    Induction of sexual reproduction in the facultatively sexual Chlamydomonas reinhardtii is cued by depletion of nitrogen. We explore the capacity for indirect monitoring of population variation in the gametogenic process using flow cytometry. We describe a high-throughput method capable of identifying fluorescence, ploidy and scatter profiles that track vegetative cells entering and undergoing gametogenesis. We demonstrate for the first time, that very early and late growth phases reduce the capacity to distinguish putative gametes from vegetative cells based on scatter and fluorescence profiles, and that early/mid-logarithmic cultures show the optimal distinction between vegetative cells and gamete scatter profiles. We argue that early/mid logarithmic cultures are valuable in such high throughput comparative approaches when investigating optimisation or quantification of gametogenesis based on scatter and fluorescence profiles. This approach provides new insights into the impact of culture conditions on gametogenesis, while documenting novel scatter and fluorescence profile shifts which typify the process. This method has potential applications to; enabling quick high-throughput monitoring, uses in increasing efficiency in the quantification of gametogenesis, as a method of comparing the switch between vegetative and gametic states across treatments, and as criteria for enrichment of gametic phenotypes in cell sorting assays. PMID:27676075

  8. Molecular characterization of phytoplankton dissolved organic matter (DOM) and sulfur components using high resolution Orbitrap mass spectrometry.

    Science.gov (United States)

    Mangal, Vaughn; Stock, Naomi L; Guéguen, Celine

    2016-03-01

    Orbitrap high resolution mass spectrometry (HRMS) with electrospray ionization in both positive and negative polarity was conducted on Suwannee River fulvic acid (SRFA), Pony Lake fulvic acid (PLFA) standards, and dissolved organic matter (DOM) released by freshwater phytoplankton (Scenedesmus obliquus, Euglena mutabilis, and Euglena gracilis). Three-dimensional van Krevelen diagrams expressing various oxygenation states of sulfur molecules and abundance plots of sulfur-containing species were constructed. Orbitrap HRMS analysis of SRFA found a high density of peaks in the lignin region (77 %) and low density of protein material (6.53 %), whereas for PLFA, 25 % of the total peaks were lignin related compared to 56 % of peaks in protein regions, comparable with other HRMS studies. Phytoplankton-derived DOM of S. obliquus, E. mutabilis, and E. gracilis was dominated by protein molecules at respective percentages of 36, 46, and 49 %, and is consistent with previous experiments examining phytoplankton-derived DOM composition. The normalized percentage of SO-containing compounds was determined among the three phytoplankton to be 56 % for Scenedesmus, 54 % for E. mutabilis, and 47 % for E. gracilis, suggesting variation between sulfur content in phytoplankton-derived DOM and differences in metal binding capacities. These results suggest the level of resolution by Orbitrap mass spectrometry is sufficient for preliminary characterization of phytoplankton DOM at an affordable cost relative to other HRMS techniques.

  9. Urban wastewater treatment by seven species of microalgae and an algal bloom: Biomass production, N and P removal kinetics and harvestability.

    Science.gov (United States)

    Mennaa, Fatima Zahra; Arbib, Zouhayr; Perales, José Antonio

    2015-10-15

    This study evaluates the capacity of seven species and a Bloom of microalgae to grow in urban wastewater. Nutrient removal kinetics and biomass harvesting by means of centrifugation and coagulation-flocculation-sedimentation have been also tested. Results show that the best biomass productivities ranged from between 118 and 108 mgSS L(-1) d(-1) for the Bloom (Bl) and Scenedesmus obliquus (Sco). Regarding nutrient removal, microalgae were able to remove the total dissolved phosphorus and nitrogen concentrations by more than 80% and 87% respectively, depending on the species tested. The final total dissolved concentration of nitrogen and phosphorus in the culture media complies with the European Commission Directive 98/15/CE on urban wastewater treatment. Regarding harvesting, the results of coagulation-flocculation sedimentation using a 60 mg L(-1) dose of Ferric chloride were similar between species, exceeding the biomass removal efficiency by more than 90%. The results of centrifugation (time required to remove 90% of solids at 1000 rpm) were not similar between species, with the shortest time being 2.9 min for Sco, followed by the bloom (7.25 min). An overall analysis suggested that the natural bloom and Scenedesmus obliquus seem to be the best candidates to grow in pre-treated wastewater, according to their biomass production, nutrient removal capability and harvestability. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. A Novel Miniature Culture System to Screen CO2-Sequestering Microalgae

    Directory of Open Access Journals (Sweden)

    Xiaoling Miao

    2012-11-01

    Full Text Available In this study, a novel 96-well microplate swivel system (M96SS was built for high-throughput screening of microalgal strains for CO2 fixation. Cell growth under different CO2 supply conditions (0.2, 0.4, 0.8, and 1.2 g L−1 d−1, residual nitrate, and pH value of Chlorella sp. SJTU-3, Chlorella pyrenoidosa SJTU-2, and Scenedesmus obliquus SJTU-3 were examined in the M96SS and traditional flask cultures. The dynamic data showed there was a good agreement between the systems. Two critical problems in miniature culture systems (intra-well mixing and evaporation loss were improved by sealed vertical mixing of the M96SS. A sample screen of six microalgal species (Chlorella sp. SJTU-3, Chlorella pyrenoidosa SJTU-2, Selenastrum capricornutum, Scenedesmus obliquus SJTU-3, Chlamydomonas sajao, Dunaliella primolecta was carried out in flasks and the M96SS. Chlamydomonas sajao appeared to be a robust performer (highest cell density: 1.437 g L−1 in anaerobic pond water with 0.8, and 1.2 g L−1 d−1 CO2. The reliability and efficiency of the M96SS were verified through a comparison of traditional flask culture, M96SS, Lukavský’s system, and a microplate shaker.

  11. Oil production towards biofuel from autotrophic microalgae semicontinuous cultivations monitorized by flow cytometry.

    Science.gov (United States)

    da Silva, Teresa Lopes; Reis, Alberto; Medeiros, Roberto; Oliveira, Ana Cristina; Gouveia, Luisa

    2009-11-01

    Two microalgae species (Scenedesmus obliquus and Neochloris oleoabundans) were cultivated in closed sleeve photobioreactors in order to select the best oil producer for further large-scale open raceway pond cultivations, aiming at biofuel production. Scenedesmus obliquus reached a higher maximum biomass concentration (1.41 g l(-1)) with a lower lipid content (12.8% w/w), as compared to N. oleoabundans [maximum biomass concentration of 0.92 g l(-1) with 16.5% (w/w) lipid content]. Both microalgae showed adequate fatty acid composition and iodine values as substitutes for diesel fuel. Based on these results, N. oleoabundans was selected for further open raceway pond cultivations. Under these conditions, N. oleoabundans reached a maximum biomass concentration of 2.8 g l(-1) with 11% (w/w) of lipid content. A high correlation between the Nile Red fluorescence intensity measured by flow cytometry and total lipid content assayed by the traditional gravimetric lipid analysis was found for both microalgae, making this method a suitable and quick technique for the screening of microalgae strains for lipid production and optimization of biofuel production bioprocesses. Medium growth optimization for enhancement of microalgal oil production is now in progress.

  12. Radiocesium bioaccumulation in freshwater plankton: Influences of cation concentrations (K{sup +} and Na{sup +}) on direct uptake of {sup 137}Cs in Chlamydomonas, Scenedesmus and Daphnia. Food-chain transfer of {sup 137}Cs from Chlamydomonas to Daphnia at different K{sup +} concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Hagstroem, J. [Uppsala Univ., Dept. of Limnology, Uppsala (Sweden)

    2002-04-01

    The influences of cation concentrations (K{sup +} and Na{sup +}) on radiocesium ({sup 137}Cs) bioaccumulation in two freshwater phytoplankton species (Scenedesmus quadricauda and Chlamydomonas noctigama) were systematically investigated in batch-cultures monitored during two weeks. Both species were cultured at 9 {mu}E M{sup -2} s{sup -1} constant illumination at 20 deg. C. The exponential growth phase lasted for more than 100 hours ({mu} {approx_equal} 0.02 h{sup -1} for C. noctigama and 0.03 h{sup -1} for S, quadricauda). Over cation concentration ranges encountered in natural fresh waters ([K{sup +}] from 0.1 {mu}M to 3 mM, [Na{sup +}] from 20 {mu}M to 3 mM), a more than three order of magnitude variation was found for both intake rate and observed bioconcentration factors (BCF) at apparent steady-state (from less than 10{sup 3} to 10{sup 6} L (kg C){sup -1}). For both species, the major effector on BCF and uptake rate was external [K{sup +}], which was inversely proportional to these parameters over wide ranges (1-1000 {mu}M for S. quadricauda and 0.1 to 300 {mu}M for C. noctigama). At concentrations above these ranges K{sup +} still reduced {sup 137} Cs bio-uptake, but less effectively. A minor influence of external [Na{sup +}] on {sup 137}Cs bioaccumulation was indicated for S. quadricauda, whereas no such influence was significant for C. noctigama. A biphasic pattern for {sup 137}Cs bioaccumulation was discovered in C. noctigama. A rapid 'quasi-steady state' with an effective equilibration time of less than 100 hours was approached during the exponential growth phase. A surge in the uptake occurred when exponential growth ceased, and this pattern was consistent over the range 30 {mu}M to 1.4 mM external [K{sup +}]. Since depletion of external [K{sup +}] was not detected for these treatments, this pattern can only be explained if there are at least two different cellular compartments involved. Although less certain, a second steady-state BCF

  13. Deri Endüstrisi Atıksularından Kromun Çeşitli Alglerle Biyosorpsiyonu

    Directory of Open Access Journals (Sweden)

    T. NAKİBOĞLU

    2009-04-01

    Full Text Available Bu makalede yapılan kinetik testlerin amacı, deri endüstrisi atıksularından Cr(VI metalinin Scenedesmus obliquus ve Chlorella sp. ile biyosorpsiyonu için optimum reaksiyon süresinin ve optimum karıştırma hızının belirlenmesidir. Scenedesmus obliquus ve Chlorella sp. ile orijinal atıksu ve sentetik atıksuda yapılan Cr(VI biyosorpsiyon çalışmaları sonucunda optimum karıştırma süreleri sırasıyla 24 saat ve 6 saat olarak belirlenmiştir. Optimum karıştırma hızı her iki alg biyokütlesi için orijinal atıksu ve sentetik atıksuda 150 devir/dakika olarak belirlenmiştir. Makalede yapılan izoterm testlerinin amacı, deri endüstrisi atıksularından Cr(VI metalinin Scenedesmus obliquus ve Chlorella sp. ile biyosorpsiyonu için optimum pH, optimum sıcaklık ve optimum alg dozajını belirlemektir. Scenedesmus obliquus ve Chlorella sp. ile orijinal atıksu ve sentetik atıksuda yapılan biyosorpsiyon çalışmaları sonucunda optimum pH'lar sırasıyla 2 ve 1 olarak belirlenmiştir. Her iki alg türü için orijinal atıksu ve sentetik atıksuda optimum biyosorpsiyon sıcaklığı 250C olarak bulunmuştur. Optimum şartlarda orijinal atıksu ve sentetik atıksuda en yüksek Cr(VI giderimi yapan alg dozajları, her iki alg türü için 0.5 g/L olarak belirlenmiştir. Çalışma kapsamında, deri endüstrisi atıksularında bulunan Cr(VI ağır metal iyonlarının, Scenedesmus obliquus ve Chlorella sp. ile maksimum biyosorpsiyon kapasiteleri araştırılmış ve maksimum biyosorpsiyon kapasiteyi sağlayacak reaktör işletme koşulları (optimum karıştırma süresi, optimum karıştırma hızı, optimum pH, optimum sıcaklık, optimum alg dozajı belirlenmiştir.

  14. The growth of Scenedesmus sp. attachment on different materials surface.

    Science.gov (United States)

    Chen, Xiaolin; Liu, Tianzhong; Wang, Qiang

    2014-10-01

    Microalgae has been concerned as a potential source of biodiesel in the recent years. However, it is costly to harvest microalgae as it is commonly cultured in water and the cells are too small to harvest. In order to reduce the cost of cultivation and harvesting, it is important to improve the biomass productivity of microalgae. Here, we utilized the attachment method to culture microalgae to cut off the cost of culture and harvest. In this paper, various supporting surface with different hydrophility including polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polysulfone (PS), which are not easy to be degraded in the culture medium, were used for microalgae culture by the attachment method. The results showed that PVDF supporting cloth was suitable for the algae growth, and its average biomass productivity was to 4.0 g/m2/day. Furthermore, a series of PVDF concentrations were tested, and cloth treated with 3% or 5% PVDF solution was better for the algae culture. In addition, Polyvinylpyrrolidone (PVP) with different molecular weight was added to the PVDF solution as porogens to produce rough surface. And the addition of PVP resulted in better growth with 6.0 g/m2/day of average biomass productivity. This attachment method makes the harvest of microalgae easy and energy-saving, because the microalgae grow on the supporting material and is easy to be scraped. The results indicate that the PVDF-treated cloth is a potential alternative for the microalgae attachment culture.

  15. Characterization of a newly isolated green microalga Scenedesmus ...

    African Journals Online (AJOL)

    The effects of salinity on the biomass, lipid, and carotenoid productions of the alga SP-01 in mixotrophic mode were investigated. The biomass productivity increased with increasing NaNO3 concentrations, and addition of NaCl resulted in a higher biomass while NaNO3 was present. The maximum lipid content was ...

  16. Comparative toxicity of the plasticizer dibutyl phthalate to two freshwater algae.

    Science.gov (United States)

    Gu, Shurui; Zheng, Hao; Xu, Qingqing; Sun, Cuizhu; Shi, Mei; Wang, Zhenyu; Li, Fengmin

    2017-10-01

    Phthalate esters (PAEs), a family of emerging environmental contaminants, have been frequently detected in soils and water. However, intensive studies on the toxicity of PAEs have focused on growth response of terrestrial and aquatic animals, while only limited attention has been paid to aquatic plants, especially phytoplankton, the primary producer in aquatic ecosystems. Therefore, the acute toxic effects and underlying mechanisms of dibutyl phthalate (DBP) at different concentrations (0-20mgL -1 ) on two typical freshwater algae (Scenedesmus obliquus and Chlorella pyrenoidosa) were investigated. The growth of S. obliquus and C. pyrenoidosa was conspicuously inhibited by DBP exposure at 2-20mgL -1 . The 96-h median effective concentration values (96h-EC 50 ) were 15.3mgL -1 and 3.14mgL -1 for S. obliquus and C. pyrenoidosa, respectively, implying that the spherical C. pyrenoidosa is more sensitive to DBP than the spindle-shaped S. obliquus. As expected from the damage done to cell organelles (i.e. cell membranes, chloroplasts, and protein rings), cell densities and chlorophyll content conspicuously decreased under DBP treatments. Moreover, the algal growth inhibition was closely linked to the increased production of intracellular reactive oxygen species and malondialdehyde content, indicating oxidative stress and lipid peroxidation in both algae. This was proved by the increased activity of antioxidant enzymes such as superoxide dismutase and catalase. Our findings will contribute to the understanding of toxic mechanisms in PAEs and the evaluation of environmental risks for primary producers in aquatic ecosystems. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Nutrient removal and biogas upgrading by integrating freshwater algae cultivation with piggery anaerobic digestate liquid treatment.

    Science.gov (United States)

    Xu, Jie; Zhao, Yongjun; Zhao, Guohua; Zhang, Hui

    2015-08-01

    An integrated approach that combined freshwater microalgae Scenedesmus obliquus (FACHB-31) cultivation with piggery anaerobic digestate liquid treatment was investigated in this study. The characteristics of algal growth, biogas production, and nutrient removal were examined using photobioreactor bags (PBRbs) to cultivate S. obliquus (FACHB-31) in digestate with various digestate dilutions (the concentration levels of 3200, 2200, 1600, 1200, 800, and 400 mg L(-1) chemical oxygen demand (COD)) during 7-day period. The effects of the level of pollutants on nutrient removal efficiency and CO2 removal process were investigated to select the optimum system for effectively upgrade biogas and simultaneously reduce the nutrient content in digestate. The treatment performance displayed that average removal rates of COD, total nitrogen (TN), total phosphorous (TP), and CO2 were 61.58-75.29, 58.39-74.63, 70.09-88.79, and 54.26-73.81 %, respectively. All the strains grew well under any the dilution treatments. With increased initial nutrient concentration to a certain range, the CO4 content (v/v) of raw biogas increased. Differences in the biogas enrichment of S. obliquus (FACHB-31) in all treatments mainly resulted from variations in biomass productivity and CO2 uptake. Notably, the diluted digestate sample of 1600 mg L(-1) COD provided an optimal nutrient concentration for S. obliquus (FACHB-31) cultivation, where the advantageous nutrient and CO2 removals, as well as the highest productivities of biomass and biogas upgrading, were revealed. Results showed that microalgal biomass production offered real opportunities to address issues such as CO2 sequestration, wastewater treatment, and biogas production.

  18. Estrutura da comunidade de Chlorococcales sensu lato (Chlorophyceae em diferentes hábitats aquáticos e hidroperíodos Structure of the Chlorococcales sensu lato (Chlorophyceae community in different aquatic habitats and hydroperiods

    Directory of Open Access Journals (Sweden)

    Lezilda Carvalho Torgan

    2011-03-01

    Full Text Available Este estudo visa avaliar a riqueza, a densidade, a diversidade específica e a distribuição da comunidade de Chlorococcales s.l. em zonas pelágicas e litorâneas de diferentes hábitats aquáticos (lagoas isoladas, lagoas interligadas, banhados, açudes e arroios em dois hidroperíodos (águas altas e baixas em região subtropical no sul do Brasil. As amostragens de fitoplâncton foram realizadas em duas áreas, situadas entre as coordenadas 30(040´ - 30(010´ S e 50(030´ - 51(031´W no ano de 2003, com a obtenção simultânea de dados de temperatura, condutividade, pH, transparência e profundidade da água. Os resultados revelaram que as médias de riqueza e de diversidade específica foram maiores na zona litorânea e significativamente maiores (p24°C. Dentre os táxons observados, Desmodesmus heteracanthus (Guerr. Hentschke et Torgan, D. lunatus (W. et G. S. West Hegew. e Monoraphidium griffithii (Berk. Kom-Legn., mostraram-se indicadoras de hábitats e D. armatus (Chod. Hegew., D. denticulatus (Lagerh. An, Friedl et Hegew. e D. lunatus foram indicadoras de hidroperíodo. Este estudo demonstra a importância do hábitat e do hidroperíodo, na estrutura da comunidade de Chlorococcales s.l.This study aims to evaluate richness, density specific diversity and distribution of the Chlorococcales s.l. community in pelagic and littoral zones of different aquatic habitats (isolated lagoons, interlinked lagoons, swamps, reservoirs and streams during two hydroperiods (high and low water in a subtropical region in Southern Brazil. Phytoplankton sampling was carried out in two areas, situated within the coordinates 30(040´ - 30(010´ S and 50(030´ - 51(031´ W, in 2003 with simultaneous information on temperature, conductivity, pH, transparency and depth of water. The results showed that richness and specific diversity averages were higher in the littoral zone and significantly higher (p24°C. Among the observed taxa Desmodesmus heteracanthus (Guerr. Hentschke & Torgan, D. lunatus (W. et G. S. West Hegew. and Monoraphidium griffithii (Berk. Kom-Legn. were habitat indicators and D. armatus (Chod. Hegew., D. denticulatus (Lagerh. An, Friedl et Hegew. and D. lunatus were hydroperiod indicators. This study shows the importance of habitats and hydroperiods for Chlorococcales s.l. community structure.

  19. Chlorodiscus natans Peter. & Hans. (Chlorophyceae from a mesotrophic peat bog in Lower Silesia (South-Western Poland

    Directory of Open Access Journals (Sweden)

    Jan Matula

    2011-01-01

    Full Text Available The paper concerns a very rare and poorly known species of green alga Chlorodiscus natans Petersen & Hansen, discovered in the peat bog "Brzeźnik" near Bolesławiec (Poland. This is the second stand so far discovered in the world. The collected material allowed complementing the knowledge on organization of colonies, morphology and way of hair development. The remaining features, particularly the structure of the cell, are in concordance with the hitherto diagnosis of that species. The paper presents problems connected with the taxonomic affiliation of the species and describes the ecological conditions of habitats occupied by this alga.

  20. Xanthophyll cycle activity and photosynthesis of Dunaliella tertiolecta (Chlorophyceae) and Thalassiosira weissflogii (Bacillariophyceae) during fluctuating solar radiation

    NARCIS (Netherlands)

    van de Poll, Willem H.; Buma, Anita G. J.; Visser, Ronald J. W.; Janknegt, Paul J.; Villafane, Virginia E.; Helbling, E. Walter

    Short-term ultraviolet (UV) radiation (280-400 nm) effects on xanthophyll cycle activity and photosynthesis were assessed during fluctuating irradiance (60- and 10-min cycles - saturating irradiance to near-zero irradiance) for the marine algae Thalassiosira (Bacillariophyceae) and Dunaliella

  1. A curious occurrence of Hazenia broadyi spec. nova in Antarctica and the review of the genus Hazenia (Ulotrichales, Chlorophyceae)

    Czech Academy of Sciences Publication Activity Database

    Škaloud, P.; Nedbalová, Linda; Elster, Josef; Komárek, Jiří

    2013-01-01

    Roč. 36, č. 9 (2013), s. 1281-1291 ISSN 0722-4060 R&D Projects: GA MŠk ME 945 Institutional support: RVO:67985939 Keywords : Antarctica * green algae * lakes Subject RIV: EH - Ecology, Behaviour Impact factor: 2.071, year: 2013

  2. Cryopreservation of economically valuable marine micro-algae in the classes Bacillariophyceae, Chlorophyceae, Cyanophyceae, Dinophyceae, Haptophyceae, Prasinophyceae, and Rhodophyceae.

    Science.gov (United States)

    Rhodes, Lesley; Smith, John; Tervit, Robin; Roberts, Rodney; Adamson, Janet; Adams, Serean; Decker, Marie

    2006-02-01

    The ability to routinely cryopreserve micro-algal species reduces costs associated with maintaining large culture collections and reduces the risks of losing particular strains or species through contamination and genetic drift. Cryopreservation is also a useful adjunct in aquaculture hatcheries for strains of micro-algae where the nutritional status may change as a result of continuous sub-culture. In this study, cryopreservation of isolates from seven micro-algal classes was investigated. Successful candidates included the marine dinoflagellates Amphidinium carterae, Amphidinium trulla, and Gymnodinium simplex, and the haptophytes Chrysochromulina simplex, Prymnesium parvum, Prymnesium parvum f. patelliferum, Isochrysis galbana, and Pavlova lutheri. Also successfully cryopreserved were the planktonic diatoms Chaetoceros calcitrans, Chaetoceros muelleri, Chaetoceros sp., and the benthic Nitzschia ovalis, the chlorophyte Chlamydomonas coccoides, the rhodophyte Porphyridium purpureum, the prasinophytes Tetraselmis chuii, and Tetraselmis suecica, and the cyanophytes Raphidiopsis sp., and Aphanizomenon flos-aquae. All species were successfully cryopreserved using 15% Me2SO.

  3. Photobioreactor cultivation and catalytic pyrolysis of the microalga Desmodesmus communis (Chlorophyceae) for hydrocarbons production by HZSM-5 zeolite cracking.

    Science.gov (United States)

    Conti, Roberto; Pezzolesi, Laura; Pistocchi, Rossella; Torri, Cristian; Massoli, Patrizio; Fabbri, Daniele

    2016-12-01

    The study evaluated the growth of Desmodesmus communis on column photobioreactor and its thermochemical treatment by catalytic pyrolysis using HZSM-5 zeolite. D. communis showed good results in terms of growth (0.05gL -1 d -1 ). Analytical pyrolysis of original algae and derived bio-oil mixed with zeolite was used as a screening method in order to gather information on the cracking process. Preparative pyrolysis on bench scale reactor was performed on algae biomass over a zeolite bed at 1:10 ratio (wt/wt). Py-GC-MS of biomass/catalyst mixture showed that the denitrogenation/deoxygenation increased with increasing zeolite load from 1:5 to 1:20 ratio and became significant at 1:10 ratio. The composition observed by analytical pyrolysis was featured by the predominance of alkylated monoaromatic hydrocarbons. The scaling-up to bench scale confirmed the results obtained with analytical pyrolysis in terms of monoaromatic hydrocarbons. However, low yield of catalytic oil (8% by weight) was observed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Chloroplast phylogenomic data from the green algal order Sphaeropleales (Chlorophyceae, Chlorophyta) reveal complex patterns of sequence evolution.

    Science.gov (United States)

    Fučíková, Karolina; Lewis, Paul O; Lewis, Louise A

    2016-05-01

    Chloroplast sequence data are widely used to infer phylogenies of plants and algae. With the increasing availability of complete chloroplast genome sequences, the opportunity arises to resolve ancient divergences that were heretofore problematic. On the flip side, properly analyzing large multi-gene data sets can be a major challenge, as these data may be riddled with systematic biases and conflicting signals. Our study contributes new data from nine complete and four fragmentary chloroplast genome sequences across the green algal order Sphaeropleales. Our phylogenetic analyses of a 56-gene data set show that analyzing these data on a nucleotide level yields a well-supported phylogeny - yet one that is quite different from a corresponding amino acid analysis. We offer some possible explanations for this conflict through a range of analyses of modified data sets. In addition, we characterize the newly sequenced genomes in terms of their structure and content, thereby further contributing to the knowledge of chloroplast genome evolution. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Effects of elevated pCO2 on physiological performance of marine microalgae Dunaliella salina (Chlorophyta, Chlorophyceae)

    Science.gov (United States)

    Hu, Shunxin; Wang, You; Wang, Ying; Zhao, Yan; Zhang, Xinxin; Zhang, Yongsheng; Jiang, Ming; Tang, Xuexi

    2017-06-01

    The present study was conducted to determine the effects of elevated pCO2 on growth, photosynthesis, dark respiration and inorganic carbon acquisition in the marine microalga Dunaliella salina. To accomplish this, D. salina was incubated in semi-continuous cultures under present-day CO2 levels (390 μatm, pHNBS: 8.10), predicted year 2100 CO2 levels (1 000 μatm, pHNBS: 7.78) and predicted year 2300 CO2 levels (2 000 μatm, pHNBS: 7.49). Elevated pCO2 significantly enhanced photosynthesis (in terms of gross photosynthetic O2 evolution, effective quantum yield (ΔF/F' m ), photosynthetic efficiency (α), maximum relative electron transport rate (rETRmax) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity) and dark respiration of D. salina, but had insignificant effects on growth. The photosynthetic O2 evolution of D. salina was significantly inhibited by the inhibitors acetazolamide (AZ), ethoxyzolamide (EZ) and 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS), indicating that D. salina is capable of acquiring HCO3 - via extracellular carbonic anhydrase and anion-exchange proteins. Furthermore, the lower inhibition of the photosynthetic O2 evolution at high pCO2 levels by AZ, EZ and DIDS and the decreased carbonic anhydrase showed that carbon concentrating mechanisms were down-regulated at high pCO2. In conclusion, our results show that photosynthesis, dark respiration and CCMs will be affected by the increased pCO2/low pH conditions predicted for the future, but that the responses of D. salina to high pCO2/low pH might be modulated by other environmental factors such as light, nutrients and temperature. Therefore, further studies are needed to determine the interactive effects of pCO2, temperature, light and nutrients on marine microalgae.

  6. Nucleotide diversity of the colorless green alga Polytomella parva (Chlorophyceae, Chlorophyta): high for the mitochondrial telomeres, surprisingly low everywhere else.

    Science.gov (United States)

    Smith, David Roy; Lee, Robert W

    2011-01-01

    Silent-site nucleotide diversity data (π(silent)) can provide insights into the forces driving genome evolution. Here we present π(silent) statistics for the mitochondrial and nuclear DNAs of Polytomella parva, a nonphotosynthetic green alga with a highly reduced, linear fragmented mitochondrial genome. We show that this species harbors very little genetic diversity, with the exception of the mitochondrial telomeres, which have an excess of polymorphic sites. These data are compared with previously published π(silent) values from the mitochondrial and nuclear genomes of the model species Chlamydomonas reinhardtii and Volvox carteri, which are close relatives of P. parva, and are used to understand the modes and tempos of genome evolution within green algae. © 2011 The Author(s). Journal of Eukaryotic Microbiology © 2011 International Society of Protistologists.

  7. Insights into Microalga and Bacteria Interactions of Selected Phycosphere Biofilms Using Metagenomic, Transcriptomic, and Proteomic Approaches

    Directory of Open Access Journals (Sweden)

    Ines Krohn-Molt

    2017-10-01

    Full Text Available Microalga are of high relevance for the global carbon cycling and it is well-known that they are associated with a microbiota. However, it remains unclear, if the associated microbiota, often found in phycosphere biofilms, is specific for the microalga strains and which role individual bacterial taxa play. Here we provide experimental evidence that Chlorella saccharophila, Scenedesmus quadricauda, and Micrasterias crux-melitensis, maintained in strain collections, are associated with unique and specific microbial populations. Deep metagenome sequencing, binning approaches, secretome analyses in combination with RNA-Seq data implied fundamental differences in the gene expression profiles of the microbiota associated with the different microalga. Our metatranscriptome analyses indicates that the transcriptionally most active bacteria with respect to key genes commonly involved in plant–microbe interactions in the Chlorella (Trebouxiophyceae and Scenedesmus (Chlorophyceae strains belong to the phylum of the α-Proteobacteria. In contrast, in the Micrasterias (Zygnematophyceae phycosphere biofilm bacteria affiliated with the phylum of the Bacteroidetes showed the highest gene expression rates. We furthermore show that effector molecules known from plant–microbe interactions as inducers for the innate immunity are already of relevance at this evolutionary early plant-microbiome level.

  8. Growth of three microalgae strains and nutrient removal from an agro-zootechnical digestate.

    Science.gov (United States)

    Franchino, Marta; Comino, Elena; Bona, Francesca; Riggio, Vincenzo A

    2013-07-01

    In this paper three microalgae strains (Neochloris oleoabundans, Chlorella vulgaris and Scenedesmus obliquus) were cultivated on an agro-zootechnical digestate in comparable conditions. The material used as growth media was obtained from a pilot plant anaerobic digestor used to digest several mixes of cattle slurry and raw cheese whey. The main aims were to compare the algae growth, their tolerance with respect to the various dilutions of digestate, their nutrient removal efficiency and their role in the transformation of nitrogen compounds. C. vulgaris presented the highest elimination capacity of ammonium in 1:10 digestate sample; it was also observed that only 4% of ammonia was removed with stripping, microalgal and bacterial consortium recovered the remaining 96%. The three strains almost completely removed different nitrogen forms and phosphate in 11d. The results show that microalgal biomass production offers real opportunities for addressing issues such CO2 sequestration, biofuel production and wastewater treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. The need to implement an efficient biomass fractionation and full utilization based on the concept of "biorefinery" for a viable economic utilization of microalgae.

    Science.gov (United States)

    Dibenedetto, Angela; Colucci, Antonella; Aresta, Michele

    2016-11-01

    In the present work, microalgae strains, such as Scenedesmus obliquus and Phaeodactylum tricornutum grown in indoor/outdoor photobioreactors (PBRs) and in open ponds (this is the first study on such strains cultivated in the local Southern Italy climatic conditions), were fully analyzed for their protein content, carbohydrates, lipids, and fatty acid profile in order to assess their potential use for the production of biofuels, chemicals, and omega-3, and as animal feed and human food. They are compared with Nannochloropsis sp. (commercial sample) which was fully analyzed in our laboratory and Chlorella (literature data). An economic evaluation was carried out, demonstrating that the cultivation of microalgae for the production of only biofuels will not match the economic standards. Conversely, if chemicals are also produced applying the biorefinery concept and using wastewater as a source of nutrients, it will be possible to have a good positive return from microalgae.

  10. Attached cultivation technology of microalgae for efficient biomass feedstock production.

    Science.gov (United States)

    Liu, Tianzhong; Wang, Junfeng; Hu, Qiang; Cheng, Pengfei; Ji, Bei; Liu, Jinli; Chen, Yu; Zhang, Wei; Chen, Xiaoling; Chen, Lin; Gao, Lili; Ji, Chunli; Wang, Hui

    2013-01-01

    The potential of microalgae biofuel has not been realized because of low productivity and high costs associated with the current cultivation systems. In this paper, an attached cultivation method was introduced, in which microalgae cells grew on the surface of vertical artificial supporting material to form algal film. Multiple of the algal films were assembled in an array fashion to dilute solar irradiation to facilitate high photosynthetic efficiency. Results showed that a broad range of microalgae species can grow with this attached method. A biomass productivity of 50-80 g m(-2) d(-1) was obtained outdoors for Scenedesmus obliquus, corresponding to the photosynthetic efficiency of 5.2-8.3% (total solar radiation). This attached method also offers lots of possible advantages over traditional open ponds, such as on water saving, harvesting, contamination controlling and scale-up. The attached cultivation represents a promising technology for economically viable production of microalgae biofuels. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Isolation and application of SO{sub X} and NO{sub X} resistant microalgae in biofixation of CO{sub 2} from thermoelectricity plants

    Energy Technology Data Exchange (ETDEWEB)

    Radmann, Elisangela Martha; Vieira Camerini, Felipe; Duarte Santos, Thaisa [Laboratory of Biochemical Engineering, College of Chemistry and Food Engineering, Federal University of Rio Grande (FURG), P.O. Box 474, Rio Grande-RS 96201-900 (Brazil); Vieira Costa, Jorge Alberto, E-mail: dqmjorge@furg.br [Laboratory of Biochemical Engineering, College of Chemistry and Food Engineering, Federal University of Rio Grande (FURG), P.O. Box 474, Rio Grande-RS 96201-900 (Brazil)

    2011-09-15

    Highlights: {yields} Microalgae can help reduce global warming. {yields} Synechococcus nidulans and Chlorella vulgaris were isolated in a thermoelectric plant. {yields} Microalgae were compared with Spirulina and Scenedesmus obliquus for CO{sub 2} fixation. {yields} Microalgae were exposed to CO{sub 2}, SO{sub 2} and NO, simulating a gas from coal combustion. {yields} C. vulgaris and Spirulina sp. showed 13.43% of maximum daily fixation. - Abstract: Microalgae have been studied for their potential use in foodstuffs, agriculture, in the treatment of wastewater and, in particular, in the reduction of atmospheric carbon dioxide, the main cause of global warming. Thermoelectricity plants account for 22% of CO{sub 2} emitted into the atmosphere and native microalgae may be more tolerant to the gases emitted from burning fossil fuels. In the study presented here, microalgae were isolated from ponds next to a Thermoelectricity Plant, located in southern Brazil, and identified as Synechococcus nidulans and Chlorella vulgaris. The isolated microalgae were grown and compared with two different strains of microalgae, Spirulina sp. and Scenedesmus obliquus, for CO{sub 2} biofixation. The microalgae were exposed to 12% CO{sub 2}, 60 ppm of SO{sub 2} and 100 ppm of NO, simulating a gas from coal combustion. The C. vulgaris had similar behavior to Spirulina sp., with 13.43% of maximum daily fixation. The microalgae with the greater fixing capacity were C. vulgaris and Spirulina sp. and these can be grown in electric power plants for CO{sub 2} biofixation of the coal combustion gas, which would help reduce global warming.

  12. Nanoplastic affects growth of S. obliquus and reproduction of D. magna

    NARCIS (Netherlands)

    Besseling, E.; Wang, B.; Lürling, M.F.L.L.W.; Koelmans, A.A.

    2014-01-01

    The amount of nano- and microplastic in the aquatic environment rises due to the industrial production of plastic and the degradation of plastic into smaller particles. Concerns have been raised about their incorporation into food webs. Little is known about the fate and effects of nanoplastic,

  13. Fungi & Health: can polysaccharides from the fungus inonotus obliquus (CHAGA) inhibit tumor growth?

    DEFF Research Database (Denmark)

    Wold, C. W.; Corthay, A.; Kjeldsen, Christian

    cancer. The last few decades, studies have found Chaga to contain biologically active substances such as polysaccharides, triterpenoids, polyphenols and melanin. In vivo effects such as tumor growth inhibition have been observed in mice receiving various Chaga extracts. The main hypothesis behind...

  14. Biofixation of CO2 from synthetic combustion gas using cultivated microalgae in three-stage serial tubular photobioreactors.

    Science.gov (United States)

    Morais, Michele G; Radmann, Elisângela M; Costa, Jorge A V

    2011-01-01

    Coal is the most abundant of the fossil fuels, with reserves estimated at 102 billions of tons. The feasibility of using coal as a fuel depends upon reducing emissions of gas when it is burnt, such as carbon dioxide (CO2), sulfur oxides (SO(x)), and nitrogen oxides (NO(x)). The removal of CO2 with microalgae may be one of the most efficient ways of reducing this gas, without the need for radical changes in the world's energy supply and production methods. Spirulina sp. LEB-18 and Scenedesmus obliquus LEB-22 were cultivated in serial tubular photobioreactors, with the aim of measuring the potential of CO2 biofixation and the resistance of the microalgae to SO2 and NO. Spirulina sp. and S. obliquus had CO2 biofixation scores of 0.27 and 0.22 g L(-1) d(-1), respectively. Both microalgae were resistant to SO2 and NO, and grew during the 15 d they were cultivated, which proves that using microalgae is an efficient method of biofixation of CO2 emitted when fossil fuels are burnt.

  15. [Fe]-hydrogenases in green algae: photo-fermentation and hydrogen evolution under sulfur deprivation

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, M.; Hemschemeier, A.; Happe, T. [Botanisches Institut der Universitat Bonn (Germany); Gotor, C. [CSIC y Universidad de Sevilla (Spain). Instituto de Bioquimica Vegetal y Fotosintesis; Melis, A. [University of California, Berkeley, CA (United States). Department of Plant and Microbial Biology

    2002-12-01

    Recent studies indicate that [Fe]-hydrogenases and H{sub 2} metabolism are widely distributed among green algae. The enzymes are simple structured and catalyze H{sub 2} evolution with similar rates than the more complex [Fe]-hydrogenases from bacteria. Different green algal species developed diverse strategies to survive under sulfur deprivation. Chlamydomonas reinhardtii evolves large quantities of hydrogen gas in the absence of sulfur. In a sealed culture of C. reinhardtii, the photosynthetic O{sub 2} evolution rate drops below the rate of respiratory O{sub 2} consumption due to a reversible inhibition of photosystem II, thus leading to an intracellular anaerobiosis. The algal cells survive under these anaerobic conditions by switching their metabolism to a kind of photo-fermentation. Although possessing a functional [Fe]-hydrogenase gene, the cells of Scenedesmus obliquus produce no significant amounts of H{sub 2} under S-depleted conditions. Biochemical analyses indicate that S. obliquus decreases almost the complete metabolic activities while maintaining a low level of respiratory activity. (author)

  16. Oxidation of c-Type Cytochromes by the Membrane-Bound Cytochrome Oxidase (Cytochrome aa(3)) of Blue-Green Algae.

    Science.gov (United States)

    Kienzl, P F; Peschek, G A

    1982-03-01

    Respiratory particles containing an aa(3)-type cytochrome oxidase were prepared from Anacystis nidulans, Synechocystis 6714, Synechococcus lividus, Anabaena variabilis, Nostoc sp. strain MAC, Nostoc muscorum, and Mastigocladus laminosus. Oxidation of c-type cytochromes by membrane preparations of the different blue-green algae was observed using purified cytochromes from horse heart, Candida krusei, tuna, Saccharomyces oviformis, Rhodospirillum rubrum, Rhodospirillum molischianum, Rhodopseudomonas palustris, Rhodocyclus purpureus, Paracoccus denitrificans, Anacystis nidulans, Anabaena variabilis, Euglena gracilis, and Scenedesmus obliquus. Rapid oxidations were consistently observed with the mitochondrial c-type cytochromes (horse heart cytochrome c reacts most rapidly) and with cytochromes c(2) from Rhodopseudomonas palustris and Rhodocyclus purpureus; in contrast, the cytochrome c(2) from Rhodospirillum rubrum and the plastidic cytochromes from E. gracilis and Scendesmus obliquus were inactive with all membrane preparations. All reactions were inhibited by low concentrations of KCN, NaN(3), and CO, and they were activated by Tween 80, thus indicating participation of the terminal oxidase. The results are discussed in view of the spectral similarities between the terminal oxidase of blue-green algae and the mitochondrial aa(3)-type cytochrome oxidase of plants and other eukaryotes.

  17. Combining urban wastewater treatment with biohydrogen production--an integrated microalgae-based approach.

    Science.gov (United States)

    Batista, Ana Paula; Ambrosano, Lucas; Graça, Sofia; Sousa, Catarina; Marques, Paula A S S; Ribeiro, Belina; Botrel, Elberis P; Castro Neto, Pedro; Gouveia, Luisa

    2015-05-01

    The aim of the present work was the simultaneous treatment of urban wastewater using microalgae and the energetic valorization of the obtained biomass. Chlorella vulgaris (Cv), Scenedesmus obliquus (Sc) and a naturally occurring algal Consortium C (ConsC) were grown in an urban wastewater. The nutrient removals were quite high and the treated water fits the legislation (PT Dec-Lei 236/98) in what concerns the parameters analysed (N, P, COD). After nutrient depletion the microalgae remained two more weeks in the photobioreactor (PBR) under nutritional stress conditions, to induce sugar accumulation (22-43%). The stressed biomass was converted into biohydrogen (bioH2), a clean energy carrier, through dark fermentation by a strain of the bacteria Enterobacter aerogenes. The fermentation kinetics were monitored and fitted to a modified Gompertz model. The highest bioH2 production yield was obtained for S. obliquus (56.8 mL H2/gVS) which was very similar when using the same algae grown in synthetic media. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Biohydrogen production from microalgal biomass: energy requirement, CO2 emissions and scale-up scenarios.

    Science.gov (United States)

    Ferreira, Ana F; Ortigueira, Joana; Alves, Luís; Gouveia, Luísa; Moura, Patrícia; Silva, Carla

    2013-09-01

    This paper presents a life cycle inventory of biohydrogen production by Clostridium butyricum through the fermentation of the whole Scenedesmus obliquus biomass. The main purpose of this work was to determine the energy consumption and CO2 emissions during the production of hydrogen. This was accomplished through the fermentation of the microalgal biomass cultivated in an outdoor raceway pond and the preparation of the inoculum and culture media. The scale-up scenarios are discussed aiming for a potential application to a fuel cell hybrid taxi fleet. The H2 yield obtained was 7.3 g H2/kg of S. obliquus dried biomass. The results show that the production of biohydrogen required 71-100 MJ/MJ(H2) and emitted about 5-6 kg CO2/MJ(H2). Other studies and production technologies were taken into account to discuss an eventual process scale-up. Increased production rates of microalgal biomass and biohydrogen are necessary for bioH2 to become competitive with conventional production pathways. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Evaluation of the potential for trophic transfer of roxithromycin along an experimental food chain.

    Science.gov (United States)

    Ding, Jiannan; Lu, Guanghua; Liu, Jianchao; Zhang, Zhenghua

    2015-07-01

    Pharmaceuticals have been recognized as a new class of environmental pollutants in recent years. But data about their potential for transfer and biomagnification in aquatic food chains are still lacking. In this study, bioaccumulation of the macrolide antibiotic roxithromycin (ROX) was determined in an experimental aquatic food chain involving the green algae Scenedesmus obliquus, the water flea Daphnia magna and the crucian carp Carassius auratus. After 48 h of exposure, S. obliquus accumulated ROX from media, with bioconcentration factors (BCFs) of 74.6, 46.3, and 24.5 l kg(-1) at nominal exposure concentrations of 4, 20, and 100 μg l(-1), respectively. After 48 h of feeding ROX-contaminated algae, D. magna was able to accumulate ROX in all three concentration treatments, but biomagnification did not occur at this trophic level, as biomagnification factors (BMFs) varied from 0.21 to 0.29 in different concentration treatments were well below one. In tissues (muscle, gill, liver, and bile) of C. auratus fed with contaminated daphnia for 8 days, no biomagnification was observed. However, this species did accumulate a certain degree of ROX through food chain transfer, and the tissue burden was greatest in the liver > muscle > gill and lowest in the bile. This work suggests that the trophic transfer should be a matter of concern for ecological risk assessments of pharmaceutical substances in aquatic food webs.

  20. Utilization of non-conventional systems for conversion of biomass to food components

    Science.gov (United States)

    Karel, M.; Nakhost, Z.

    1989-01-01

    Described here is work accomplished in investigating the potential use of micro-algae in yielding useful macronutrients for closed ecological life support systems in space habitats. Analysis of the chemical composition of the blue-green alga Synechoccus 6311 was done in the present work, and was compared to values found in previous work on the green algae Scenedesmus obliquus. Similar values were obtained for proteins, and lower values for nucleic acids and lipids. A second part of the work involved fabrication of food products containing various levels of incorporated algae (S. obliquus) proteins and/or lipids. Protein isolate was incorporated into a variety of food products such as bran muffins, fettuccine (spinach noodle imitation), and chocolate chip cookies. In the sensory analysis, the greenish color of the bran muffins and cookies was not found to be objectionable. The mild spinachy flavor was less detectable in chocolate chip cookies than in bran muffins. The color and taste of the algae noodles were found to be pleasant and compared well with commercially available spinach noodles.

  1. Coleção de microalgas de ambientes dulciaquícolas naturais da Bahia, Brasil, como potencial fonte para a produção de biocombustíveis: uma abordagem taxonômica Collection of microalgae from natural freshwater environments of Bahia, Brazil, as a potential source for biofuel production: a taxonomic approach

    Directory of Open Access Journals (Sweden)

    Maria Cristina de Queiroz Mendes

    2012-09-01

    Full Text Available O presente trabalho envolveu a identificação taxonômica de espécies nativas de microalgas (isoladas de ecossistemas dulciaquícolas localizados nos arredores de Salvador, Bahia integrantes da Coleção de Microalgas dulciaquícolas do LABIOMAR/IB/UFBA, visando estudos taxonômicos mais aprofundados (ultraestruturais e moleculares e experimentos que possam avaliar sua capacidade para suprir cadeias produtivas de biocombustíveis. As coletas foram realizadas nos arredores de Salvador, Bahia, Brasil. A identificação das espécies foi efetuada com base em caracteres morfológicos. Foram identificados 19 táxons, 12 em nível de espécie e nove em nível de gênero, sendo 14 Chlorophyceae (Chlamydomonas sp1, Chlamydomonas sp2, Chlamydomonas sp3, Chlamydocapsa bacillus (Teiling Fott, Chlorococcum sp1, Chlorococcum sp2, Coelastrum indicum Turn.. Coelastrum microporum Nägeli, Desmodesmus brasiliensis (Bohl. Hegew, Scenedesmum obliquus (Turpin Kütz, Ankistrodesmus falcatus (Corda Ralfs, Ankistrodesmus fusiformis Corda, Kirchneriella lunaris (Kirchner. Möbius, Pseudokirchneriella subcapitata (Korshikov F. Hindák, três Trebouxiophyceae (Botryococcus braunii Kütz., Botryococcus terribilis Komárek et Marvan e Chlorella vulgaris Beijerinck, uma Bacillariophyceae (Nitzschia sp. e uma Cyanobacteria (Synechocystis sp..This study identified native species of microalgae (maintained at LABIOMAR/IB/UFBA Collection of Freshwater Microalgae to indicate their potential to supply the biofuel production chain. Samples were collected in freshwater ecosystems around Salvador, Bahia, Brazil. Species identification was based in morphological characteristics. Nineteen species were isolated and identified, 12 at the level of species and nine at the level of genus: 14 Chlorophyceae (Chlamydomonas sp1, Chlamydomonas sp2, Chlamydomonas sp3, Chlamydocapsa bacillus (Teiling Fott, Chlorococcum sp1, Chlorococcum sp2, Coelastrum indicum Turn. Coelastrum microporum N

  2. Capability of different microalgae species for phytoremediation processes: wastewater tertiary treatment, CO2 bio-fixation and low cost biofuels production.

    Science.gov (United States)

    Arbib, Zouhayr; Ruiz, Jesús; Álvarez-Díaz, Pablo; Garrido-Pérez, Carmen; Perales, José A

    2014-02-01

    Scenedesmus obliquus, Chlorella vulgaris, Chlorella kessleri and a natural Bloom were cultivated in batch experiments, under controlled conditions, in urban wastewater (WW) and synthetic wastewater (SW) under 5% CO2 in air, with the object of estimating their capacity for nutrient removal, carbon dioxide biofixation, and generation of valuable biomass. In both culture media, the Bloom (Bl) and Scenedesmus (Sc) showed higher final biomass concentration (dried weight, dw) than the other species; the maximum yield obtained was 1950 ± 243 mg L(-1) for Bl and the minimum 821 ± 88 mg L(-1) for Cv, both in synthetic wastewater. Maximum specific growth rate values do not show significant differences between any of the 4 strains tested (p ≤ 0.05), nor between the 2 culture media. A new homogeneous method of calculating productivities has been proposed. Nitrogen removal in all the reactors was higher than 90%, except for BlSW (79%), and for phosphorus, the removal was higher than 98% in all trials. Maximum CO2 consumption rates reached were 424.4 and 436.7 mg L(-1) d(-1) for ScSW and ScWW respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. ITS2 data corroborate a monophyletic chlorophycean DO-group (Sphaeropleales

    Directory of Open Access Journals (Sweden)

    Dandekar Thomas

    2008-07-01

    Full Text Available Abstract Background Within Chlorophyceae the ITS2 secondary structure shows an unbranched helix I, except for the 'Hydrodictyon' and the 'Scenedesmus' clade having a ramified first helix. The latter two are classified within the Sphaeropleales, characterised by directly opposed basal bodies in their flagellar apparatuses (DO-group. Previous studies could not resolve the taxonomic position of the 'Sphaeroplea' clade within the Chlorophyceae without ambiguity and two pivotal questions remain open: (1 Is the DO-group monophyletic and (2 is a branched helix I an apomorphic feature of the DO-group? In the present study we analysed the secondary structure of three newly obtained ITS2 sequences classified within the 'Sphaeroplea' clade and resolved sphaeroplealean relationships by applying different phylogenetic approaches based on a combined sequence-structure alignment. Results The newly obtained ITS2 sequences of Ankyra judayi, Atractomorpha porcata and Sphaeroplea annulina of the 'Sphaeroplea' clade do not show any branching in the secondary structure of their helix I. All applied phylogenetic methods highly support the 'Sphaeroplea' clade as a sister group to the 'core Sphaeropleales'. Thus, the DO-group is monophyletic. Furthermore, based on characteristics in the sequence-structure alignment one is able to distinguish distinct lineages within the green algae. Conclusion In green algae, a branched helix I in the secondary structure of the ITS2 evolves past the 'Sphaeroplea' clade. A branched helix I is an apomorph characteristic within the monophyletic DO-group. Our results corroborate the fundamental relevance of including the secondary structure in sequence analysis and phylogenetics.

  4. Lineage-specific fragmentation and nuclear relocation of the mitochondrial cox2 gene in chlorophycean green algae (Chlorophyta).

    Science.gov (United States)

    Rodríguez-Salinas, Elizabeth; Riveros-Rosas, Héctor; Li, Zhongkui; Fucíková, Karolina; Brand, Jerry J; Lewis, Louise A; González-Halphen, Diego

    2012-07-01

    In most eukaryotes the subunit 2 of cytochrome c oxidase (COX2) is encoded in intact mitochondrial genes. Some green algae, however, exhibit split cox2 genes (cox2a and cox2b) encoding two polypeptides (COX2A and COX2B) that form a heterodimeric COX2 subunit. Here, we analyzed the distribution of intact and split cox2 gene sequences in 39 phylogenetically diverse green algae in phylum Chlorophyta obtained from databases (28 sequences from 22 taxa) and from new cox2 data generated in this work (23 sequences from 18 taxa). Our results support previous observations based on a smaller number of taxa, indicating that algae in classes Prasinophyceae, Ulvophyceae, and Trebouxiophyceae contain orthodox, intact mitochondrial cox2 genes. In contrast, all of the algae in Chlorophyceae that we examined exhibited split cox2 genes, and could be separated into two groups: one that has a mitochondrion-localized cox2a gene and a nucleus-localized cox2b gene ("Scenedesmus-like"), and another that has both cox2a and cox2b genes in the nucleus ("Chlamydomonas-like"). The location of the split cox2a and cox2b genes was inferred using five different criteria: differences in amino acid sequences, codon usage (mitochondrial vs. nuclear), codon preference (third position frequencies), presence of nucleotide sequences encoding mitochondrial targeting sequences and presence of spliceosomal introns. Distinct green algae could be grouped according to the form of cox2 gene they contain: intact or fragmented, mitochondrion- or nucleus-localized, and intron-containing or intron-less. We present a model describing the events that led to mitochondrial cox2 gene fragmentation and the independent and sequential migration of cox2a and cox2b genes to the nucleus in chlorophycean green algae. We also suggest that the distribution of the different forms of the cox2 gene provides important insights into the phylogenetic relationships among major groups of Chlorophyceae.

  5. Effects of temperature, genetic variation and species competition on the sensitivity of algae populations to the antibiotic enrofloxacin.

    Science.gov (United States)

    Rico, Andreu; Zhao, Wenkai; Gillissen, Frits; Lürling, Miquel; Van den Brink, Paul J

    2018-02-01

    Primary producers are amongst the most sensitive organisms to antibiotic pollution in aquatic ecosystems. To date, there is little information on how different environmental conditions may affect their sensitivity to antibiotics. In this study we assessed how temperature, genetic variation and species competition may affect the sensitivity of the cyanobacterium Microcystis aeruginosa and the green-algae Scenedesmus obliquus to the antibiotic enrofloxacin. First, we performed single-species tests to assess the toxicity of enrofloxacin under different temperature conditions (20°C and 30°C) and to assess the sensitivity of different species strains using a standard temperature (20°C). Next, we investigated how enrofloxacin contamination may affect the competition between M. aeruginosa and S. obliquus. A competition experiment was performed following a full factorial design with different competition treatments, defined as density ratios (i.e. initial bio-volume of 25/75%, 10/90% and 1/99% of S. obliquus/M. aeruginosa, respectively), one 100% S. obliquus treatment and one 100% M. aeruginosa treatment, and four different enrofloxacin concentrations (i.e. control, 0.01, 0.05 and 0.10mg/L). Growth inhibition based on cell number, bio-volume, chlorophyll-a concentration as well as photosynthetic activity were used as evaluation endpoints in the single-species tests, while growth inhibition based on measured chlorophyll-a was primarily used in the competition experiment. M. aeruginosa photosynthetic activity was found to be the most sensitive endpoint to enrofloxacin (EC50-72h =0.02mg/L), followed by growth inhibition based on cell number. S. obliquus was found to be slightly more sensitive at 20°C than at 30°C (EC50-72h cell number growth inhibition of 38 and 41mg/L, respectively), whereas an opposite trend was observed for M. aeruginosa (0.047 and 0.037mg/L, respectively). Differences in EC50-72h values between algal strains of the same species were within a factor

  6. Periphytic algal community in artificial and natural substratum in a tributary of the Rosana reservoir (Corvo Stream, Paraná State, Brazil - doi: 10.4025/actascibiolsci.v32i4.4627 Periphytic algal community in artificial and natural substratum in a tributary of the Rosana reservoir (Corvo Stream, Paraná State, Brazil - doi: 10.4025/actascibiolsci.v32i4.4627

    Directory of Open Access Journals (Sweden)

    Liliana Rodrigues

    2010-11-01

    Full Text Available Periphytic algal community in artificial and natural substratum in a tributary of the Rosana reservoir (Corvo Stream, Paraná State, Brazil. This study evaluated the heterogeneity in periphytic algal community, under the influence of time colonization on artificial substratum. We also examined which abiotic variables most influenced the community in natural and artificial substratum. Egeria najas Planchon was used as natural substratum, and a plastic plant, as artificial. This experiment was carried out in a lateral arm from Rosana Reservoir, formed by Corvo Stream (Paranapanema river basin, in the period from November 21st to December 12nd, 2003, characterized as a warm and rainy period. Changes in species composition were assessed using the similarity indices. 495 taxa were registered in the phycoperiphytic community, distributed in 133 genera and 11 classes. Zygnemaphyceae, Bacillariophyceae, Chlorophyceae and Cyanophyceae presented higher species number, in both substrata. Staurodesmus, Closterium, Staurastrum and Cosmarium (Desmidiales; Gomphonema and Eunotia (Pennales; Characium, Scenedesmus and Desmodesmus (Chlorococcales; Anabaena and Aphanocapsa (Nostocales and Chroococcales, respectively were the most species-rich genera. The epiphytic community reached the highest species richness in the 15th successional day. Regardless the substratum type, the number of species was probably related to the high concentrations of nutrients (phosphorus and nitrogen.Periphytic algal community in artificial and natural substratum in a tributary of the Rosana reservoir (Corvo Stream, Paraná State, Brazil. This study evaluated the heterogeneity in periphytic algal community, under the influence of time colonization on artificial substratum. We also examined which abiotic variables most influenced the community in natural and artificial substratum. Egeria najas Planchon was used as natural substratum, and a plastic plant, as artificial. This experiment was

  7. Isolation and Identification of Kairomone(s) in the Daphnia-Scenedesmus System

    NARCIS (Netherlands)

    Holthoon, van F.L.

    2004-01-01

    Infochemicals play an important role in interactions between living organisms in aquatic environments. Although the presence of these chemical cues is confirmed in more and more systems, the chemical structures of the compounds involved remain predominantly elusive and the identification of these

  8. Influence of organic waste and inorganic nitrogen source on biomass productivity of Scenedesmus and Chlorococcum sp.

    Energy Technology Data Exchange (ETDEWEB)

    Arumugam, M.; Agarwal, A.; Arya, M.C. [Defence Institute of Bio-Energy Research, Defence R and D Organization, Ministry of Defence, Govt. of India, Field Station Pithoragarh - 262501, Uttarakhand (India); Ahmed, Z. [Defence Institute of Bio-Energy Research, Defence R and D Organization, Ministry of Defence, Govt. of India Haldwani- 263 139, Uttarakhand (India)

    2011-07-01

    Algae gaining the more attention in the recent years in order to supplement the futuristic demand of fuel requirement because of its unique feature like high productivity, short duration and higher fatty acids content. However algal culturing for large-scale production is limited due to many technical and engineering challenges. One of the main constraints for large-scale biomass production is the non-availability of cost effective and affordable growth medium for open pond condition. In order to overcome this lacuna, the present study was carried out to find out the suitable cost effective growth medium using locally available resources. Farm Yard Manure an easily available organic waste yet, rich in nutrients and used for agriculture over the generations. FYM coupled with inorganic nitrogen source like urea was found to be better alternative to the synthetic growth medium, which may make wider acceptability at farmers' field for large-scale algal mass production. The present study reveals that FYM extract of 50% supplemented with 0.1% Urea was performing better for algal biomass growth in outdoor open pond condition.

  9. Algae (Microcystis and Scenedesmus) absorption spectra and its application on Chlorophyll a retrieval

    Science.gov (United States)

    Wu, Di; Chen, Maosi; Wang, Qiao; Gao, Wei

    2013-12-01

    Blue algae and green algae are the dominant phytoplankton groups that contribute to the eutrophication and the water bloom in inland water of China. The absorption coefficients (spectra) of the algae, which do not change with its intrinsic optical characteristics and the observation geometry, are strictly additive quantities. The characteristics of the absorption spectra of the two algae are presented. The pure blue algae and the pure green algae cultured in the laboratory environment are diluted and mixed at ten volume ratios. The Quantitative Filter Technique was applied to measure their absorption spectra. The "hot-ethanol extraction" method was chosen to calculate their concentration of Chlorophyll a. The retrieval algorithm developed in this study extracts the mapping information between each individual alga and their Chlorophyll a concentration via Continuous Wavelet Transform, and retrieves the Chlorophyll a concentration of each alga in their mixture using a trust region optimizer. The results show that the retrieved and the measured Chlorophyll a concentrations of the blue algae and the green algae components in the ten mixture match well with the average relative error of 5.55%.

  10. Scenedesmus dimorphus (Turpin) Kützing growth with digestate from biogas plant in outdoor bag photobioreactors.

    Science.gov (United States)

    Barbato, F; Venditti, A; Bianco, A; Guarcini, L; Bottari, E; Festa, M R; Cogliani, E; Pignatelli, V

    2016-01-01

    Digestate coming from an Anaerobic Digestion unit in a Biogas Plant, feeded on cow manure and vegetable waste from markets, has been used. About 8-35 L polyethylene transparent bags have been employed as cultivation container, outdoor. Different aliquots of digestate, alone or mixed with commercial liquid fertiliser, were employed to cultivate in batch Scenedesus dimorphus, a freshwater green microalga, in the ENEA facilities of Casaccia Research Center, near Rome, Italy. The cultivation period was June-July 2013. The average daily yields of dry microalgae biomass varied from 20 mg/L/d to 60 mg/L/d, mean 38.2 mg/L/d. Final dry biomass concentration varied from 0.18 to 1.29 g/L, mean 0.55 g/L. S. dimorphus proved to be very efficient in removing N and P from the culture medium. Another fact emerged from these trials is that S. dimorphus inner composition resulted to be variable in response to the tested different culture conditions.

  11. Effects of a surfactant (FFD-6) on Scenedesmus morphology and growth under different nutrient conditions

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.

    2006-01-01

    Surfactants are man-made compounds that are meanwhile omnipresent in the environment, but environmental concentrations of surfactants are such that they are thought to have little risk for aquatic systems. The major anionic surfactants currently on the global market are linear alkylbenzene

  12. The smell of water : grazer-induced colony formation in Scenedesmus

    OpenAIRE

    Lürling, M.

    1999-01-01

    In aquatic systems, the phytoplankton - zooplankton relation is of major importance because it is the first step in the pelagic food chain. It is well known that zooplankton feed with a highly variable success on phytoplankton, primarily owing to algal characteristics such as size, shape, cell wall texture, nutritional quality and toxicity. Algae are present in a broad variety of shapes and may express an enormous variability in their morphology, physiology and behavior depending on ...

  13. Isolation and Identification of Kairomone(s) in the Daphnia-Scenedesmus System

    OpenAIRE

    Holthoon, van, F.L.

    2004-01-01

    Infochemicals play an important role in interactions between living organisms in aquatic environments. Although the presence of these chemical cues is confirmed in more and more systems, the chemical structures of the compounds involved remain predominantly elusive and the identification of these compounds is essential to advance the research on chemical communication. An overview of chemical cues involving Daphnia (either as producer or receiver) is given and the progress towards their isola...

  14. Influence of organic waste and inorganic nitrogen source on biomass productivity of Scenedesmus and Chlorococcum sp.

    OpenAIRE

    M. Arumugam, A. Agarwal, M.C. Arya, Z. Ahmed

    2011-01-01

    Algae gaining the more attention in the recent years in order to supplement the futuristic demand of fuel requirement because of its unique feature like high productivity, short duration and higher fatty acids content. However algal culturing for large-scale production is limited due to many technical and engineering challenges. One of the main constraints for large-scale biomass production is the non-availability of cost effective and affordable growth medium for open pond condition. In orde...

  15. The smell of water : grazer-induced colony formation in Scenedesmus

    NARCIS (Netherlands)

    Lürling, M.

    1999-01-01

    In aquatic systems, the phytoplankton - zooplankton relation is of major importance because it is the first step in the pelagic food chain. It is well known that zooplankton feed with a highly variable success on phytoplankton, primarily owing to algal characteristics such as size, shape,

  16. In vitro antigenotoxicity of Ulva rigida C. Agardh (Chlorophyceae) extract against induction of chromosome aberration, sister chromatid exchange and micronuclei by mutagenic agent MMC.

    Science.gov (United States)

    Celikler, Serap; Yildiz, Gamze; Vatan, Ozgur; Bilaloglu, Rahmi

    2008-12-01

    To determine the in vitro possible clastogenic and cytotoxic activities of Ulva rigida crude extracts (URE), and identify their antigenotoxic and protective effects on chemotherapeutic agent mitomycine-C (MMC). Anti-clastogenic and anti-genotoxic activities of Ulva rigida crude extracts (URE) were studied using chromosome aberration (CA), sister chromatid exchange (SCE), and micronuclei (MN) tests in human lymphocytes cultured in vitro. The chromosome aberration, sister chromatid exchange or micronuclei tests showed that URE at concentrations of 10, 20, and 40 microg/mL had no clastogenic activity in human lymphocyte cell culture. Three doses of URE significantly decreased the number of chromosomal aberrations and the frequencies of SCE and MN when compared with the culture treated with MMC (P MMC in vitro.

  17. The importance of light and photoperiod in sexual reproduction and geographical distribution in the green snow alga, Chloromonas sp.-D (Chlorophyceae, Volvocales)

    Science.gov (United States)

    Hoham, Ronald W.; Marcarelli, Amy M.; Rogers, Haldre S.; Ragan, Michael D.; Petre, Benjamin M.; Ungerer, Michael D.; Barnes, Joseph M.; Francis, David O.

    2000-12-01

    The effects of premating light regimes on sexual reproduction and the production of spherical cells in Chloromonas sp.-D, a unicellular green snow alga, were studied using cross-mating strains 582C and 582D isolated from snowpacks associated with mixed hardwood- softwood forests in Whetstone Gulf State Park, Tughill Plateau, NY. Two pre-acclimation regimes were used, Vita-Lite as controls (530- 700 nm peak) and blue light as experimentals (430- 460 nm peak) prior to the mating experiments. In blue light, an increase in the number of matings and spherical cells (spheres) produced in the life cycle was observed as the photoperiod increased. This implies that longer photoperiods of blue light are more optimal for sexual reproduction in Chloromonas sp.-D than shorter ones. Under Vita-Lite, there was a significant increase in the number of matings and spheres with the extended 20 : 4 photoperiod compared with the shorter 14 : 10 photoperiod. Under blue light, significantly more matings and spheres occurred than under Vita-Lite using the same irradiance level of 95µmol photons m-2 s-1 (photosynthetically active radiation [PAR] of 400- 700 nm) for the 14 : 10 and 20 : 4 photoperiods. The results of these experiments suggest that Chloromonas sp.-D, known only from the Tughill Plateau, NY, is not reproducing optimally at this site where it grows and reproduces under an approximate 14 : 10 photoperiod in early April. However, in the upper 10 cm of snow in the Tughill Plateau, a blue light irradiance level of 95µmol photons m-2 s-1 occurs, which is optimal for this species. When these conditions are combined with a 14 : 10 photoperiod, the Tughill Plateau appears to be sub-optimal for mating and production of spherical cells. Since Chloromonas sp.-D does not appear to have a dependence on a dark cycle, this would allow it to expand its geographical distribution. It may reproduce more optimally under blue light (95µmol photons m-2 s-1) with an extended photoperiod (>20 : 4 h, light:dark) in high latitude field sites such as Lake Bienville, Québec, in eastern North America where other species of Chloromonas are known in snow associated with coniferous forests.

  18. Differences in pyrenoid morphology are correlated with differences in the rbcL genes of members of the Chloromonas lineage (volvocales, chlorophyceae).

    Science.gov (United States)

    Nozaki, Hisayoshi; Onishi, Keisuke; Morita, Eiko

    2002-10-01

    Chloromonas is distinguished from Chlamydomonas primarily by the absence of pyrenoids, which are structures that are present in the chloroplasts of most algae and are composed primarily of the CO2-fixing enzyme Rubisco. In this study we compared sequences of the rbcL (Rubisco large subunit-encoding) genes of pyrenoid-less Chloromonas species with those of closely related pyrenoid-containing Chlamydomonas species in the "Chloromonas lineage" and with those of 45 other green algae. We found that the proteins encoded by the rbcL genes had a much higher level of amino acid substitution in members of the Chloromonas lineage than they did in other algae. This kind of elevated substitution rate was not observed, however, in the deduced proteins encoded by two other chloroplast genes that we analyzed: atpB and psaB. The rates of synonymous and nonsynonymous nucleotide substitutions in the rbcL genes indicate that the rapid evolution of these genes in members of the Chloromonas lineage is not due to relaxed selection (as it presumably is in parasitic land plants). A phylogenetic tree based on rbcL nucleotide sequences nested two Chlamydomonas species as a "pyrenoid-regained" clade within a monophyletic Chloromonas "pyrenoid-lost" clade. Character-state optimization with this tree suggested that the loss and the regain of pyrenoids were accompanied by eight synapomorphic amino acid replacements in the Rubisco large subunit, four of which are positioned in the region involved in its dimerization. However, both the atpB and the psaB sequence data gave robust support for a rather different set of phylogenetic relationships in which neither the "pyrenoid-lost" nor the "pyrenoid-regained" clade was resolved. The appearance of such clades in the rbcL-based tree may be an artifact of convergent evolutionary changes that have occurred in a region of the large subunit that determines whether Rubisco molecules will aggregate to form a visible pyrenoid.

  19. The Xanthophyceae and Chlorophyceae of the Western Ross Sea, Victoria Land, Antarctica and Macquarie Island collected under the direction of Prof. Dr. J. S. Zaneveld (1963—1967)

    NARCIS (Netherlands)

    Wagner, H.P.; Zaneveld, J.S.

    1988-01-01

    During the austral summer seasons of 1963-1964 and 1964-1965, and during the austral winter season of 1967 Prof. Dr. J.S. Zaneveld made collection expeditions to the western Ross Sea. In 1965 collections were also made from the U.S.C.G. icebreaker ‘Glacier’, around the western Ross Sea and around

  20. Selection of native Tunisian microalgae for simultaneous wastewater treatment and biofuel production.

    Science.gov (United States)

    Jebali, A; Acién, F G; Gómez, C; Fernández-Sevilla, J M; Mhiri, N; Karray, F; Dhouib, A; Molina-Grima, E; Sayadi, S

    2015-12-01

    This paper focuses on the selection of native microalgae strains suitable for wastewater treatment and biofuel production. Four Chlorophyceae strains were isolated from North-eastern Tunisia. Their performances were compared in continuous mode at a 0.3 1/day dilution rate. The biomass productivity and nutrient removal capacity of each microalgae strain were studied. The most efficient strain was identified as Scenedesmus sp. and experiments at different dilution rates from 0.2 to 0.8 1/day were carried out. Maximal biomass productivity of 0.9 g/L day was obtained at 0.6 1/day. The removal of chemical oxygen demand (COD), ammonium and phosphorus was in the range of 92-94%, 61-99% and 93-99%, respectively. Carbohydrates were the major biomass fraction followed by lipids and then proteins. The saponifiable fatty acid content was in the 4.9-13.2% dry biomass range, with more than 50% of total fatty acids being composed of saturated and monosaturated fatty acids. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. To flee or not to flee: detection, avoidance and attraction of profitable resources by Daphnia magna studied with olfactometer

    Directory of Open Access Journals (Sweden)

    Johann P. Müller

    2013-10-01

    Full Text Available The cladoceran herbivore Daphnia magna is a major consumer of phytoplankton in lakes. Therefore, this organism may control the phytoplankton community and the proliferation of some algae or cyanobacteria. Cladoceran behaviour and migration in relation to temperature, light or presence of planktivorous fishes have been well studied. In particular, it is known that the detection of kairomones produced by predators may induce avoidance. Avoidance could also occur with other semiochemicals such as cyanotoxins. In order to explore this hypothesis, we used an olfactometer to observe and measure the exploratory behaviour of D. magna individuals based on the motivation for food. Daphnids were allowed to choose between different compounds: water, a pure cyanotoxin, i.e. the microcystin-RR [(MC-RR], extracts of one MC-producing strain (PMC 75.02 and one MC-free strain (PMC 87.02 of Planktothrix agardhii, or a green algae Scenedesmus obliquus. With this experimental design, we observed that i cladocerans are able to detect resources with different qualities, ii they can explore before exhibiting preferences, and iii daphnids are able to avoid compounds that are potentially toxic (e.g., microcystins. First, daphnids explored the environment, subsequently (after about 1.5 h, they showed a significant tendency to stay where there is a profitable resource such as S. obliquus. These results also suggest that specimens of D. magna cannot detect MC compounds from P. agardhii, but they respond to it as a food resource. The study of zooplankton ability to explore the environment when exposed to semiochemicals needs further investigation. 

  2. Phosphorus and Nitrogen Recycle Following Algal Bio-crude Production via Continuous Hydrothermal Liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    Edmundson, Scott J.; Huesemann, Michael H.; Kruk, Robert; Lemmon, Teresa L.; Billing, Justin M.; Schmidt, Andrew J.; Anderson, Daniel B.

    2017-07-25

    Phosphorus and nitrogen are essential components of microalgal growth media. Critical to a wide range of biochemical processes, they commonly limit primary productivity. Recycling elemental phosphorus and fixed nitrogen after fuel conversion via hydrothermal liquefaction (HTL) of algae biomass reduces the need for mined phosphorus and synthetic nitrogen resources. Scenedesmus obliquus DOE 0152.Z and Chlorella sorokiniana DOE1412 were used as test organisms in assessing nutrient recycle of phosphorus from filtered solids collected downstream of the HTL reactor and nitrogen collected from the aqueous phase after gravimetric biocrude separation. Maximum specific growth rates were measured in growth media using HTL waste as the sole source of either phosphorus or nitrogen and were compared to an algal growth medium control (BG-11). The maximum specific growth rate of both organisms in the recycled phosphorus medium were nearly identical to rates observed in the control medium. Both organisms showed significantly reduced growth rates in the recycled nitrogen medium. C. sorokiniana DOE1412 adapted after several days of exposure whereas S. obliquus DOE0152.Z exhibited poor adaptability to the recycled nitrogen medium. After adaptation, growth rates observed with C. sorokiniana DOE1412 in the recycled nitrogen medium were 3.02 (±0.13) day-1, 89% of the control medium (3.40 ±0.21). We further tested maximum specific growth rates of C. sorokiniana DOE1412 in a medium derived entirely from HTL byproducts, completely replacing all components including nitrogen and phosphorus. In this medium we observed rates of 2.70 ±0.05 day-1, 79% of the control. Adding trace metals to this recycled medium improved growth rates significantly to 3.10 ±0.10, 91% of the control, indicating a critical element is lost in the conversion process. Recycling elemental resources such as phosphorus and nitrogen from the HTL biofuel conversion process can provide a significant reduction in media

  3. A novel one-stage cultivation/fermentation strategy for improved biogas production with microalgal biomass.

    Science.gov (United States)

    Klassen, Viktor; Blifernez-Klassen, Olga; Hoekzema, Yoep; Mussgnug, Jan H; Kruse, Olaf

    2015-12-10

    The use of alga biomass for biogas generation has been studied for over fifty years but until today, several distinct features, like inefficient degradation and low C/N ratios, limit the applicability of algal biomass for biogas production in larger scale. In this work we investigated a novel, one-stage combined cultivation/fermentation strategy including inherently progressing nitrogen starvation conditions to generate improved microalgal biomass substrates. For this strategy, comparable low amounts of nitrogen fertilizers were applied during cultivation and no additional enzymatic, chemical or physical pretreatments had to be performed. The results of this study demonstrate that progressing nitrogen limitation leads to continuously increasing C/N ratios of the biomass up to levels of 24-26 for all three tested alga strains (Chlamydomonas reinhardtii, Parachlorella kessleri and Scenedesmus obliquus). Importantly, the degradation efficiency of the algal cells increased with progressing starvation, leading to strain-specific cell disintegration efficiencies of 35%-100% during the fermentation process. Nitrogen limitation treatment resulted in a 65% increase of biogas yields for C. reinhardtii biomass (max. 698±23mL biogas g(-1) VS) when compared to replete conditions. For P. kessleri and S. obliquus, yields increased by 94% and 106% (max. 706±39mL and 586±36mL biogas g(-1) VS, respectively). From these results we conclude that this novel one-stage cultivation strategy with inherent nitrogen limitation can be used as a pretreatment for microalgal biomass generation, in order to produce accessible substrates with optimized C/N ratios for the subsequent anaerobic fermentation process, thus increasing methane production and avoiding the risk of ammonia inhibition effects within the fermenter. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. The acute toxicity of bisphenol A and lignin-derived bisphenol in algae, daphnids, and Japanese medaka.

    Science.gov (United States)

    Li, Dan; Bi, Ran; Chen, Hongxing; Mu, Lei; Zhang, Lina; Chen, Qin; Xie, Haibo; Luo, Yongju; Xie, Lingtian

    2017-10-01

    Risk assessing newly synthesized chemicals prior to their applications is extremely important, if we want to ensure substitution of risky chemicals with more benign ones. During the past two decades, many analogs of bisphenol A (BPA) have been manufactured, while their toxicity remains less studied. The aim of this study was to compare the acute toxicity of a synthesized lignin-derived BPA (LD-BP) with that of BPA in representative aquatic organisms including two algal species (Chlorella pyrenoidosa and Scenedesmus obliquus), a cladoceran species (Daphnia magna), and the Japanese medaka (Oryzias latipes). The results revealed that the two algal species showed different responses to the two chemicals. For C. pyrenoidosa, both BPA and LD-BP stimulated growth within 48 h of exposure, except for the 50 mg L -1 of LD-BP treatment. After 96 and 144 h of exposures, BPA stimulated the growth of C. pyrenoidosa at low-exposure concentrations but inhibited its growth at high concentrations, while LD-BP caused a concentration-dependent response in C. pyrenoidosa. S. obliquus exhibited a monotonic concentration-response curve for both BPA and LD-BP exposures. For both D. magna and O. latipes, concentration-responses were monotonic with 96 h-LC 50 of BPA and LD-BP of 11.7 and 5.0 mg L -1 and 9.4 and 4.1 mg L -1 , respectively. Our results demonstrate that LD-BP is more toxic than BPA in the representative aquatic organisms, and it can pose higher ecological risk to the aquatic ecosystem than BPA.

  5. Perfil de ácidos graxos de microalgas cultivadas com dióxido de carbono Fatty acids profile of microalgae cultived with carbon dioxide

    Directory of Open Access Journals (Sweden)

    Michele Greque de Morais

    2008-08-01

    Full Text Available As microalgas são consideradas fontes potenciais de diversos compostos químicos. Os ácidos graxos obtidos da biomassa podem apresentar efeitos terapêuticos em humanos e podem ser usados para produção de biodiesel. Objetivou-se, neste trabalho verificar o conteúdo lipídico e o perfil dos ácidos graxos das microalgas Spirulina sp., Scenedesmus obliquus, Chlorella kessleri e Chlorella vulgaris cultivadas em diferentes concentrações de dióxido de carbono e bicarbonato de sódio. A microalga Chlorella kessleri cultivada com 12% de CO2 apresentou a maior concentração de lipídios na biomassa seca (9,7% p/p. A máxima concentração de ácidos graxos insaturados foi 72,0% (p/p para C. vulgaris cultivada com 12% de CO2. Para os ácidos graxos saturados o maior valor encontrado foi 81,6% (p/p, quando a microalga Spirulina sp. foi cultivada com 18% de CO2 e 16,8 g.L-1 de bicarbonato de sódio.Microalgae have a great potential as a source of several chemical compounds. The fatty acids have shown therapeutic effects and used to produce biodiesel. The aim of this work was to verify the lipid contents and the fatty acids profile of the microalga Spirulina sp., Scenedesmus obliquus, Chlorella kessleri and Chlorella vulgaris cultived in different carbon dioxide and sodium bicarbonate concentrations. The microalgae Chlorella kessleri cultived with 12% CO2 showed the highest lipid content in the dry biomass (9.7% p/p. The maximum unsaturated fatty acids concentration was 72.0% (p/p to C. vulgaris in the culture with 12% CO2. The highest saturated fatty acids value was 81.6% (p/p when microalga Spirulina sp. was cultived with 18% CO2 and 16.8 g.L-1 sodium bicarbonate.

  6. Extraction of microalgae derived lipids with supercritical carbon dioxide in an industrial relevant pilot plant.

    Science.gov (United States)

    Lorenzen, Jan; Igl, Nadine; Tippelt, Marlene; Stege, Andrea; Qoura, Farah; Sohling, Ulrich; Brück, Thomas

    2017-06-01

    Microalgae are capable of producing up to 70% w/w triglycerides with respect to their dry cell weight. Since microalgae utilize the greenhouse gas CO2, they can be cultivated on marginal lands and grow up to ten times faster than terrestrial plants, the generation of algae oils is a promising option for the development of sustainable bioprocesses, that are of interest for the chemical lubricant, cosmetic and food industry. For the first time we have carried out the optimization of supercritical carbon dioxide (SCCO2) mediated lipid extraction from biomass of the microalgae Scenedesmus obliquus and Scenedesmus obtusiusculus under industrrially relevant conditions. All experiments were carried out in an industrial pilot plant setting, according to current ATEX directives, with batch sizes up to 1.3 kg. Different combinations of pressure (7-80 MPa), temperature (20-200 °C) and CO2 to biomass ratio (20-200) have been tested on the dried biomass. The most efficient conditions were found to be 12 MPa pressure, a temperature of 20 °C and a CO2 to biomass ratio of 100, resulting in a high extraction efficiency of up to 92%. Since the optimized CO2 extraction still yields a crude triglyceride product that contains various algae derived contaminants, such as chlorophyll and carotenoids, a very effective and scalable purification procedure, based on cost efficient bentonite based adsorbers, was devised. In addition to the sequential extraction and purification procedure, we present a consolidated online-bleaching procedure for algae derived oils that is realized within the supercritical CO2 extraction plant.

  7. Use of alternative media and different types of recipients in a laboratory culture of Ankistrodesmus gracilis (Reinsch Korshikov (Chlorophyceae = Utilização de meios alternativos e diferentes tipos de recipientes no cultivo de Ankistrodesmus gracilis (Reinsch Korshikov (Chlorophyceae em laboratório.

    Directory of Open Access Journals (Sweden)

    Lucia Helena Sipauba-Tavares

    2011-07-01

    Full Text Available A laboratory culture of Ankistrodesmus gracilis algae was evaluated by studying the biology of the species and its chemical composition in a traditional medium (CHU12 and in two alternative culture media, NPK (20-5-20 and macrophyte (Eichhornia crassipes + NPK, in three different types of recipients (fiberglass, carboy and plastic bag. First peak in the growth curve of Ankistrodesmus gracilis occurred on the ninth day in macrophyte + NPK medium (74.16 x 105 cells mL-1 in a fiberglass recipient. However, highest density (p 0.05 in culture media in the three recipients. Protein and fiber were similar (p > 0.05 in the treatments, but lipids were higher (p O objetivo do estudo foi avaliar os aspectos biológicos e a composição química da alga Ankistrodesmus gracilis em laboratório utilizando um meio tradicional (CHU12 e dois meios alternativos, NPK (20-5-20 e macrófita (Eichhornia crassipes + NPK em três diferentes tipos de recipientes (cuba de fibra de vidro translúcido, garrafões e saco plástico. O primeiro pico de densidade celular de Ankistrodesmus gracilis ocorreu no nono dia da curva de crescimento em meio macrófita+NPK (74,16 x 105 células mL-1 no recipiente de fibra de vidro, porém a maior densidade (p 0,05 nos três recipientes e meios de cultivo. Os teores de proteína e fibra foram similares (p > 0,05 nos tratamentos utilizados, já os de lipídios foram mais elevados (p < 0,05 no meio NPK. Os teores médios de nitrato, amônia, fósforo total e ortofosfato estiveram acima de 1 mg L-1 no meio NPK (p < 0,01. Os resultados obtidos neste estudo indicam a possibilidade do uso de meios alternativos como o NPK e macrophyte +NPK para o cultivo de A. gracilis em larga escala cultivados nos três tipos de recipientes, porém, em saco plástico o custo é baixo e ocupa menos espaço em cultivo de laboratório.

  8. Use of alternative media and different types of recipients in a laboratory culture of Ankistrodesmus gracilis (Reinsch Korshikov (Chlorophyceae - doi: 10.4025/actascibiolsci.v33i3.8046 Use of alternative media and different types of recipients in a laboratory culture of Ankistrodesmus gracilis (Reinsch Korshikov (Chlorophyceae - doi: 10.4025/actascibiolsci.v33i3.8046

    Directory of Open Access Journals (Sweden)

    Flávia de Almeida Berchielli

    2011-07-01

    Full Text Available A laboratory culture of Ankistrodesmus gracilis algae was evaluated by studying the biology of the species and its chemical composition in a traditional medium (CHU12 and in two alternative culture media, NPK (20-5-20 and macrophyte (Eichhornia crassipes + NPK, in three different types of recipients (fiberglass, carboy and plastic bag. First peak in the growth curve of Ankistrodesmus gracilis occurred on the ninth day in macrophyte + NPK medium (74.16 x 105 cells mL-1 in a fiberglass recipient. However, highest density (p 12 (122.87 x 105 cells mL-1 in a plastic bag on the twelfth day. Cell density was over 70 x 105 cells mL-1 starting on the twelfth day. Growth rate of A. gracilis was similar (p > 0.05 in culture media in the three recipients. Protein and fiber were similar (p > 0.05 in the treatments, but lipids were higher (p -1 in NPK (p A. gracilis cultured in three types of recipients. Costs are low, occupying less space when cultured in plastic bags and in the laboratory.A laboratory culture of Ankistrodesmus gracilis algae was evaluated by studying the biology of the species and its chemical composition in a traditional medium (CHU12 and in two alternative culture media, NPK (20-5-20 and macrophyte (Eichhornia crassipes + NPK, in three different types of recipients (fiberglass, carboy and plastic bag. First peak in the growth curve of Ankistrodesmus gracilis occurred on the ninth day in macrophyte + NPK medium (74.16 x 105 cells mL-1 in a fiberglass recipient. However, highest density (p 12 (122.87 x 105 cells mL-1 in a plastic bag on the twelfth day. Cell density was over 70 x 105 cells mL-1 starting on the twelfth day. Growth rate of A. gracilis was similar (p > 0.05 in culture media in the three recipients. Protein and fiber were similar (p > 0.05 in the treatments, but lipids were higher (p -1 in NPK (p A. gracilis cultured in three types of recipients. Costs are low, occupying less space when cultured in plastic bags and in the laboratory.

  9. Physicochemical, toxicological and ecological analysis of ...

    African Journals Online (AJOL)

    SERVER

    2008-02-19

    Feb 19, 2008 ... Keratococcus sp., Oocystis sp., Pediastrum dublex, Scenedesmus quadricauda,. Scenedesmus acutus, Scenedesmus sp., Selenastrum gracile, Staurastrum sp. BACILLARIOPHYTA Amphora ovalis, Cyclotella ocellata, Gomphonema sp., Navicula pupula, Navicula tuscula, Nitzschia linearis, Synedra ulna.

  10. Polymethylene-interrupted fatty acids: Biomarkers for native and exotic mussels in the Laurentian Great Lakes

    Science.gov (United States)

    Mezek, Tadej; Sverko, Ed; Ruddy, Martina D.; Zaruk, Donna; Capretta, Alfredo; Hebert, Craig E.; Fisk, Aaron T.; McGoldrick, Daryl J.; Newton, Teresa J.; Sutton, Trent M.; Koops, Marten A.; Muir, Andrew M.; Johnson, Timothy B.; Ebener, Mark P.; Arts, Michael T.

    2011-01-01

    Freshwater organisms synthesize a wide variety of fatty acids (FAs); however, the ability to synthesize and/or subsequently modify a particular FA is not universal, making it possible to use certain FAs as biomarkers. Herein we document the occurrence of unusual FAs (polymethylene-interrupted fatty acids; PMI-FAs) in select freshwater organisms in the Laurentian Great Lakes. We did not detect PMI-FAs in: (a) natural seston from Lake Erie and Hamilton Harbor (Lake Ontario), (b) various species of laboratory-cultured algae including a green alga (Scenedesmus obliquus), two cyanobacteria (Aphanizomenon flos-aquae and Synechococystis sp.), two diatoms (Asterionella formosa, Diatoma elongatum) and a chrysophyte (Dinobryon cylindricum) or, (c) zooplankton (Daphnia spp., calanoid or cyclopoid copepods) from Lake Ontario, suggesting that PMI-FAs are not substantively incorporated into consumers at the phytoplankton–zooplankton interface. However, these unusual FAs comprised 4-6% of total fatty acids (on a dry tissue weight basis) of native fat mucket (Lampsilis siliquoidea) and plain pocketbook (L. cardium) mussels and in invasive zebra (Dreissena polymorpha) and quagga (D. bugensis) mussels. We were able to clearly partition Great Lakes' mussels into three separate groups (zebra, quagga, and native mussels) based solely on their PMI-FA profiles. We also provide evidence for the trophic transfer of PMI-FAs from mussels to various fishes in Lakes Ontario and Michigan, further underlining the potential usefulness of PMI-FAs for tracking the dietary contribution of mollusks in food web and contaminant-fate studies.

  11. Triacylglycerol profiling of microalgae strains for biofuel feedstock by liquid chromatography-high-resolution mass spectrometry.

    Science.gov (United States)

    MacDougall, Karen M; McNichol, Jesse; McGinn, Patrick J; O'Leary, Stephen J B; Melanson, Jeremy E

    2011-11-01

    Biofuels from photosynthetic microalgae are quickly gaining interest as a viable carbon-neutral energy source. Typically, characterization of algal feedstock involves breaking down triacylglycerols (TAG) and other intact lipids, followed by derivatization of the fatty acids to fatty acid methyl esters prior to analysis by gas chromatography (GC). However, knowledge of the intact lipid profile could offer significant advantages for discovery stage biofuel research such as the selection of an algal strain or the optimization of growth and extraction conditions. Herein, lipid extracts from microalgae were directly analyzed by ultra-high pressure liquid chromatography-mass spectrometry (UHPLC-MS) using a benchtop Orbitrap mass spectrometer. Phospholipids, glycolipids, and TAGs were analyzed in the same chromatographic run, using a combination of accurate mass and diagnostic fragment ions for identification. Using this approach, greater than 100 unique TAGs were identified over the six algal strains studied and TAG profiles were obtained to assess their potential for biofuel applications. Under the growth conditions employed, Botryococcus braunii and Scenedesmus obliquus yielded the most comprehensive TAG profile with a high abundance of TAGs containing oleic acid.

  12. Light structures phototroph, bacterial and fungal communities at the soil surface.

    Directory of Open Access Journals (Sweden)

    Lawrence O Davies

    Full Text Available The upper few millimeters of soil harbour photosynthetic microbial communities that are structurally distinct from those of underlying bulk soil due to the presence of light. Previous studies in arid zones have demonstrated functional importance of these communities in reducing soil erosion, and enhancing carbon and nitrogen fixation. Despite being widely distributed, comparative understanding of the biodiversity of the soil surface and underlying soil is lacking, particularly in temperate zones. We investigated the establishment of soil surface communities on pasture soil in microcosms exposed to light or dark conditions, focusing on changes in phototroph, bacterial and fungal communities at the soil surface (0-3 mm and bulk soil (3-12 mm using ribosomal marker gene analyses. Microbial community structure changed with time and structurally similar phototrophic communities were found at the soil surface and in bulk soil in the light exposed microcosms suggesting that light can influence phototroph community structure even in the underlying bulk soil. 454 pyrosequencing showed a significant selection for diazotrophic cyanobacteria such as Nostoc punctiforme and Anabaena spp., in addition to the green alga Scenedesmus obliquus. The soil surface also harboured distinct heterotrophic bacterial and fungal communities in the presence of light, in particular, the selection for the phylum Firmicutes. However, these light driven changes in bacterial community structure did not extend to the underlying soil suggesting a discrete zone of influence, analogous to the rhizosphere.

  13. Different modes of TiO2 uptake by Ceriodaphnia dubia: relevance to toxicity and bioaccumulation.

    Science.gov (United States)

    Dalai, Swayamprava; Iswarya, V; Bhuvaneshwari, M; Pakrashi, Sunandan; Chandrasekaran, N; Mukherjee, Amitava

    2014-07-01

    The extensive environmental exposure of engineered metal oxide nanoparticles (NPs) may result in their bioaccumulation in aquatic organisms leading to their biotransfer in a food chain through various routes in a freshwater ecosystem. The present study focuses on the possible modes of TiO2 NP trophic transfer to Ceriodaphnia dubia, in presence and/absence of its diet, Scenedesmus obliquus (primary producer). The acute exposure studies (48h) were designed to have daphnids exposed to (i) the free NPs, (ii) both the free and the algae-borne NPs; and (iii) only the algae-borne NPs in separate tests to understand the possible routes of NP transfer. The dietary uptake of TiO2 NPs (algae-borne) was found to be the primary route for NP biotransfer with ∼70% of total NP uptake. Interestingly, in a separate study it was noticed that the NPs coated with algal exudates were easily taken up by daphnids as compared to pristine NPs of same concentrations, leading to their higher bioaccumulation. A chronic toxicity study, where daphnids were exposed to both free and algae-borne NPs for 21 days was undertaken to comprehend the TiO2 NP effect on daphnia growth and reproduction upon chronic exposure and also the bioaccumulation potential. Both acute and chronic exposure studies suggested higher bioaccumulation of TiO2 in daphnids when the particles were less toxic to the diet (algae). Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Microalgae as substrates for fermentative biogas production in a combined biorefinery concept.

    Science.gov (United States)

    Mussgnug, J H; Klassen, V; Schlüter, A; Kruse, O

    2010-10-01

    Most organic matter can be used for bioenergy generation via anaerobic fermentation. Today, crop plants like maize play the dominant role as substrates for renewable biogas production. In this work we investigated the suitability of six dominant microalgae species (freshwater and saltwater algae and cyanobacteria) as alternative substrates for biogas production. We could demonstrate that the biogas potential is strongly dependent on the species and on the pretreatment. Fermentation of the green alga Chlamydomonas reinhardtii was efficient with a production of 587 ml(±8.8 SE) biogas g volatile solids(-1) (VS(-1)), whereas fermentation of Scenedesmus obliquus was inefficient with only 287 ml(±10.1 SE) biogas g VS(-1) being produced. Drying as a pretreatment decreased the amount of biogas production to ca. 80%. The methane content of biogas from microalgae was 7-13% higher compared to biogas from maize silage. To evaluate integrative biorefinery concepts, hydrogen production in C. reinhardtii prior to anaerobic fermentation of the algae biomass was measured and resulted in an increase of biogas generation to 123% (±3.7 SE). We conclude that selected algae species can be good substrates for biogas production and that anaerobic fermentation can seriously be considered as final step in future microalgae-based biorefinery concepts. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. Benzoic Acid Interactions Affect Aquatic Properties and Toxicity of Copper Oxide Nanoparticles.

    Science.gov (United States)

    Wang, Zhuang; Fang, Hao; Wang, Se

    2016-08-01

    Effects of benzoic acid (BA) on physicochemical properties and ecotoxicities of CuO nanoparticles (CuONPs) in model aqueous media were studied. The CuONPs had larger hydrodynamic sizes and higher surface zeta potentials during 96 h of settling in the presence of BA than when the BA were not present. BA interaction with CuONPs is shown to promote dissolved Cu release from CuONPs in a dose-dependent manner. The contribution of free Cu(2+)-ions to growth inhibition toxicity of the CuONP suspensions at a toxicologically relevant concentration for the green alga Scenedesmus obliquus was around 22 %, indicating that dissolved fraction was not the major source of toxicity of CuONPs. The toxicity of CuONPs increased as the BA concentration increased. BA significantly altered total antioxidant capacity of CuONPs-exposed algal cells. The mechanism of the BA effect on the CuONPs toxicity may be mainly associated with degree of agglomeration, dissolved Cu, and particle-induced oxidative stress.

  16. Evaluation of the Antioxidant Activity of Cell Extracts from Microalgae

    Directory of Open Access Journals (Sweden)

    F. Xavier Malcata

    2013-04-01

    Full Text Available A growing market for novel antioxidants obtained from non-expensive sources justifies educated screening of microalgae for their potential antioxidant features. Characterization of the antioxidant profile of 18 species of cyanobacteria (prokaryotic microalgae and 23 species of (eukaryotic microalgae is accordingly reported in this paper. The total antioxidant capacity, accounted for by both water- and lipid-soluble antioxidants, was evaluated by the (radical cation ABTS method. For complementary characterization of cell extracts, a deoxyribose assay was carried out, as well as a bacteriophage P22/Salmonella-mediated approach. The microalga Scenedesmus obliquus strain M2-1 exhibited the highest (p > 0.05 total antioxidant capacity (149 ± 47 AAU of intracellular extracts. Its scavenger activity correlated well with its protective effects against DNA oxidative damage induced by copper(II-ascorbic acid; and against decay in bacteriophage infection capacity induced by H2O2. Finally, performance of an Ames test revealed no mutagenic effects of the said extract.

  17. Triacylglycerol profiling of microalgae strains for biofuel feedstock by liquid chromatography-high-resolution mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    MacDougall, Karen M.; McNichol, Jesse; McGinn, Patrick J.; O' Leary, Stephen J.B.; Melanson, Jeremy E. [Institute for Marine Biosciences, National Research Council of Canada, Halifax, NS (Canada)

    2011-11-15

    Biofuels from photosynthetic microalgae are quickly gaining interest as a viable carbon-neutral energy source. Typically, characterization of algal feedstock involves breaking down triacylglycerols (TAG) and other intact lipids, followed by derivatization of the fatty acids to fatty acid methyl esters prior to analysis by gas chromatography (GC). However, knowledge of the intact lipid profile could offer significant advantages for discovery stage biofuel research such as the selection of an algal strain or the optimization of growth and extraction conditions. Herein, lipid extracts from microalgae were directly analyzed by ultra-high pressure liquid chromatography-mass spectrometry (UHPLC-MS) using a benchtop Orbitrap mass spectrometer. Phospholipids, glycolipids, and TAGs were analyzed in the same chromatographic run, using a combination of accurate mass and diagnostic fragment ions for identification. Using this approach, greater than 100 unique TAGs were identified over the six algal strains studied and TAG profiles were obtained to assess their potential for biofuel applications. Under the growth conditions employed, Botryococcus braunii and Scenedesmus obliquus yielded the most comprehensive TAG profile with a high abundance of TAGs containing oleic acid. (orig.)

  18. Daphnia fed algal food grown at elevated temperature have reduced fitness

    Directory of Open Access Journals (Sweden)

    Anna B. Sikora

    2014-05-01

    Full Text Available Lake water temperature is negatively correlated with fatty acids content and P:C ratio in green algae. Hence, elevated temperature may indirectly reduce the fitness of Daphnia due to induced decrease in algal food quality. The aim of this study was to test the hypotheses that quality of algal food decreases with increasing temperature of its culture and that large-bodied Daphnia are more vulnerable to the temperature-related deterioration of algal food quality than small-bodied ones. Laboratory life-table experiments were performed at 20°C with large-bodied D. pulicaria and small-bodied D. cucullata fed with the green alga Scenedesmus obliquus, that had been grown at temperatures of 16, 24 or 32°C. The somatic growth rates of both species decreased significantly with increasing algal culture temperature and this effect was more pronounced in D. pulicaria than in D. cucullata. In the former species, age at first reproduction significantly increased and clutch size significantly decreased with increasing temperature of algae growth, while no significant changes in these two parameters were observed in the latter species. The proportion of egg-bearing females decreased with increasing algal culture temperature in both species. The results of this study support the notion that the quality of algal food decreases with increasing water temperature and also suggest that small-bodied Daphnia species might be less vulnerable to temperature-related decreases in algal food quality than large-bodied ones.

  19. Simultaneous removal of inorganic and organic compounds in wastewater by freshwater green microalgae.

    Science.gov (United States)

    Zhou, Guang-Jie; Ying, Guang-Guo; Liu, Shan; Zhou, Li-Jun; Chen, Zhi-Feng; Peng, Fu-Qiang

    2014-08-01

    Batch experiments were carried out for 7 days to investigate the simultaneous removal of various organic and inorganic contaminants including total nitrogen (TN), total phosphorus (TP), metals, pharmaceuticals and personal care products (PPCPs), endocrine disrupting chemicals (EDCs), and estrogenic activity in wastewater by four freshwater green microalgae species, Chlamydomonas reinhardtii, Scenedesmus obliquus, Chlorella pyrenoidosa and Chlorella vulgaris. After treatment for 7 days, 76.7-92.3% of TN, and 67.5-82.2% of TP were removed by these four algae species. The removal of metals from wastewater by the four algae species varied among the metal species. These four algae species could remove most of the metals efficiently (>40% removal), but showed low efficiencies in removing Pb, Ni and Co. The four algae species were also found to be efficient in removing most of the selected organic compounds with >50% removal, and the estrogenic activity with removal efficiencies ranging from 46.2 to 81.1% from the wastewater. Therefore, algae could be harnessed to simultaneously remove various contaminants in wastewater.

  20. Ammonium nitrogen removal in batch cultures treating digested piggery wastewater with microalgae Oedogonium sp.

    Science.gov (United States)

    Wang, Haiping; Hu, Zhiquan; Xiao, Bo; Cheng, Qunpeng; Li, Fanghua

    2013-01-01

    Due to the nutrient characteristics of the high concentration of available ammonium in digested piggery wastewater (DPW), microalgae can be used to treat DPW before its final discharge. Four green microalgae (Hydrodictyaceae reticulatum Lag, Scenedesmus obliquus, Oedogonium sp. and Chlorella pyrenoidosa) and three blue-green algae (Anabaena flos-aquae, Oscillatoria amoena Gom and Spirulina platensis) were used to remove the nutrients (N, P, C), especially ammonium nitrogen (NH4(+)-N), from diluted DPW with 300 mg/L algae density in batch tests. The microalgae with the best NH4(+)-N nutrient removal was then selected for further optimization of the variables to improve NH4(+)-N removal efficiency using a central composite design (CCD) experiment. Taking into account the nutrient removal efficiency, Oedogonium sp. showed the best performance (reduction of 95.9% NH4(+)-N, 92.9% total phosphorus (TP) and 62.5% chemical oxygen demand (COD)) based on the results of the batch tests. The CCD results suggested that the optimal values of variables were initial Oedogonium sp. density of 399.2 mg/L and DPW diluted by 16.3, while the predicted value of NH4(+)-N removal efficiency obtained was 97.0%.

  1. Effects of light on respiration and development of photosynthetic cells. Renewal application and progress report, March 1-November 1, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, M.

    1980-11-20

    The oxyhydrogen reaction in the presence and absence of CO/sub 2/ was studied in H/sub 2/- adapted Scenedesmus obliquus by monitoring the initial rates of H/sub 2/, O/sub 2/, and /sup 14/CO/sub 2/ uptake and the effect of inhibitors on these rates. Glucose and acetate respiration was competitive with H/sub 2/ uptake. KCN inhibited equally respiration and the oxyhydrogen reaction in the presence and absence of CO/sub 2/. It was concluded that the oxyhydrogen reaction both in the absence and presence of CO/sub 2/ has properties in common with components of respiration and photosynthesis. Participation of these two processes in the oxyhydrogen reaction would require a closely linked shuttle between mitochondrion and chloroplast. Protoplasts and chloroplasts will be isolated from a H/sub 2/-adapted alga in order to elucidate the cooperation between the two organelles. Acetate was shown to stimulate H/sub 2/ photoproduction in H/sub 2/-adapted algae even more so than an uncoupler of electron transport. The role of these compounds will be evaluated either in terms of the glyoxylate cycle or electron acceptors resulting in formation of alcohols. The term chloroplast respiration was proposed to account for the breakdown of polyglucan within the chloroplast. A means of reoxidizing reduced pyridine nucleotide was required to complete the cycle. A new enzyme ascorbic acid reduced pyridine nucleotide peroxidase was isolated from the chloroplast. The characterization of this enzyme will continue.

  2. Biological fate and effects of propranolol in an experimental aquatic food chain.

    Science.gov (United States)

    Ding, Jiannan; Lu, Guanghua; Li, Sheng; Nie, Yang; Liu, Jianchao

    2015-11-01

    The aim of this study was to evaluate the trophic transfer of the β-blocker propranolol (PRP) in an experimental aquatic food chain involving the green algae Scenedesmus obliquus, the water flea Daphnia magna and the crucian carp Carassius auratus, as well as the metabolism and effects of PRP in the liver of crucian carp. After a 48 h PRP aqueous exposure for algae, with a subsequent 48 h dietary exposure for daphnia and an 8d dietary exposure for crucian carp, PRP was observed in each trophic level, despite significant bioaccumulation did not occur in daphnia and crucian carp. A portion of the absorbed PRP was metabolized by the crucian carp to N-desisopropylated propranolol, propranolol glucuronic acid, monohydroxylated propranolol, hydroxypropranolol glucuronide and dihydroxypropranolol glucuronide, which were similar to those in mammals. In addition, multiple biomarkers in the liver of crucian carp (7-ethoxyresorufin O-deethylase, EROD; 7-benzyloxyresorufin O-dealkylation, BROD; superoxide dismutase, SOD and malondialdehyde, MDA) were measured. BROD and MDA were not significantly affected by PRP, while EROD and SOD did change significantly during the 8d dietary exposure. This work indicated that the trophic transfer of PRP, resulting in biochemical perturbations of fish biological systems, should be a concern for the assessment of the environmental risks to aquatic food chains. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Toxic effect of Cr(VI) in presence of n-TiO2 and n-Al2O3 particles towards freshwater microalgae.

    Science.gov (United States)

    Dalai, Swayamprava; Pakrashi, Sunandan; Bhuvaneshwari, M; Iswarya, V; Chandrasekaran, N; Mukherjee, Amitava

    2014-01-01

    The reactivity and toxicity of the soluble toxicants in the presence of the engineered nanomaterials is not well explored. In this study, the probable effects of TiO2 and Al2O3 nanoparticles (n-TiO2, n-Al2O3) on the toxicity of Cr(VI) were assessed with the dominant freshwater algae, Scenedesmus obliquus, in a low range of exposure concentrations (0.05, 0.5 and 1μg/mL). In the presence of 0.05μg/mL n-TiO2, the toxicity of Cr(VI) decreased considerably, which was presumably due to the Cr(VI) adsorption on the nanoparticle surface leading to its aggregation and precipitation. The elevated n-TiO2 concentrations (0.5 and 1μg/mL) did not significantly influence Cr(VI) bio-availability, and a dose dependent toxicity of Cr(VI) was observed. On the other hand, n-Al2O3 did not have any significant effect on the Cr(VI) toxicity. The microscopic observations presented additional information on the morphological changes of the algal cells in the presence of the binary toxicants. The generation of reactive oxygen species (ROS) suggested contribution of oxidative stress on toxicity and LDH release confirmed membrane permeability of algal cells upon stress. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Bioenergetic strategy of microalgae for the biodegradation of tyrosol and hydroxytyrosol.

    Science.gov (United States)

    Papazi, Aikaterini; Ioannou, Andreas; Symeonidi, Myrto; Doulis, Andreas G; Kotzabasis, Kiriakos

    2017-05-01

    Olive mill wastewater has significant polluting properties due to its high phenolic content [mainly tyrosol (trs) and hydroxytyrosol (htrs)]. Growth kinetics and a series of fluorescence induction measurements for Scenedesmus obliquus cultures showed that microalgae can be tolerant of these phenolic compounds. Changes in the cellular energy reserves and concentration of the phenolic compounds adjust the "toxicity" of these compounds to the microalgae and are, therefore, the main parameters that affect biodegradation. Autotrophic growth conditions of microalgae and high concentrations of trs or htrs induce higher biodegradation compared with mixotrophic conditions and lower phenolic concentrations. When microalgae face trs and htrs simultaneously, biodegradation begins from htrs, the more energetically demanding compound. All these lead to the conviction that microalgae have a "rational" management of cellular energy balance. Low toxicity levels lead to higher growth and lower biodegradation, whereas higher toxicity levels lead to lower growth and higher biodegradation. The selection of appropriate conditions (compatible to the bioenergetic strategies of microalgae) seems to be the key for a successful biodegradation of a series of toxic compounds, thus paving the way for future biotechnological applications for solving complicated pollution problems, like the detoxification of olive mill wastewater.

  5. Direct utilization of waste water algal biomass for ethanol production by cellulolytic Clostridium phytofermentans DSM1183.

    Science.gov (United States)

    Fathima, Anwar Aliya; Sanitha, Mary; Kumar, Thangarathinam; Iyappan, Sellamuthu; Ramya, Mohandass

    2016-02-01

    Direct bioconversion of waste water algal biomass into ethanol using Clostridium phytofermentans DSM1183 was demonstrated in this study. Fermentation of 2% (w/v) autoclaved algal biomass produced ethanol concentration of 0.52 g L(-1) (solvent yield of 0.19 g/g) where as fermentation of acid pretreated algal biomass (2%, w/v) produced ethanol concentration of 4.6 g L(-1) in GS2 media (solvent yield of 0.26 g/g). The control experiment with 2% (w/v) glucose in GS2 media produced ethanol concentration of 2.8 g L(-1) (solvent yield of 0.25 g/g). The microalgal strains from waste water algal biomass were identified as Chlamydomonas dorsoventralis, Graesiella emersonii, Coelastrum proboscideum, Scenedesmus obliquus, Micractinium sp., Desmodesmus sp., and Chlorella sp., based on ITS-2 molecular marker. The presence of glucose, galactose, xylose and rhamnose were detected by high performance liquid chromatography in the algal biomass. Scanning Electron Microscopy observations of fermentation samples showed characteristic morphological changes in algal cells and bioaccessibility of C. phytofermentans. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. The impacts of replacing air bubbles with microspheres for the clarification of algae from low cell-density culture.

    Science.gov (United States)

    Ometto, Francesco; Pozza, Carlo; Whitton, Rachel; Smyth, Beatrice; Gonzalez Torres, Andrea; Henderson, Rita K; Jarvis, Peter; Jefferson, Bruce; Villa, Raffaella

    2014-04-15

    Dissolved Air Flotation (DAF) is a well-known coagulation-flotation system applied at large scale for microalgae harvesting. Compared to conventional harvesting technologies DAF allows high cell recovery at lower energy demand. By replacing microbubbles with microspheres, the innovative Ballasted Dissolved Air Flotation (BDAF) technique has been reported to achieve the same algae cell removal efficiency, while saving up to 80% of the energy required for the conventional DAF unit. Using three different algae cultures (Scenedesmus obliquus, Chlorella vulgaris and Arthrospira maxima), the present work investigated the practical, economic and environmental advantages of the BDAF system compared to the DAF system. 99% cells separation was achieved with both systems, nevertheless, the BDAF technology allowed up to 95% coagulant reduction depending on the algae species and the pH conditions adopted. In terms of floc structure and strength, the inclusion of microspheres in the algae floc generated a looser aggregate, showing a more compact structure within single cell alga, than large and filamentous cells. Overall, BDAF appeared to be a more reliable and sustainable harvesting system than DAF, as it allowed equal cells recovery reducing energy inputs, coagulant demand and carbon emissions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Production and release of selenocyanate by different green freshwater algae in environmental and laboratory samples.

    Science.gov (United States)

    LeBlanc, Kelly L; Smith, Matthew S; Wallschläger, Dirk

    2012-06-05

    In a previous study, selenocyanate was tentatively identified as a biotransformation product when green algae were exposed to environmentally relevant concentrations of selenate. In this follow-up study, we confirm conclusively the presence of selenocyanate in Chlorella vulgaris culture medium by electrospray mass spectrometry, based on selenium's known isotopic pattern. We also demonstrate that the observed phenomenon extends to other green algae (Chlorella kesslerii and Scenedesmus obliquus) and at least one species of blue-green algae (Synechococcus leopoliensis). Further laboratory experiments show that selenocyanate production by algae is enhanced by addition of nitrate, which appears to serve as a source of cyanide produced in the algae. Ultimately, this biotransformation process was confirmed in field experiments where trace amounts of selenocyanate (0.215 ± 0.010 ppb) were observed in a eutrophic, selenium-impacted river with massive algal blooms, which consisted of filamentous green algae (Cladophora genus) and blue-green algae (Anabaena genus). Selenocyanate abundance was low despite elevated selenium concentrations, apparently due to suppression of selenate uptake by sulfate, and insufficient nitrogen concentrations. Finally, trace levels of several other unidentified selenium-containing compounds were observed in these river water samples; preliminary suggestions for their identities include thioselenate and small organic Se species.

  8. Biomass recycle as a means to improve the energy efficiency of CELSS algal culture systems

    Science.gov (United States)

    Radmer, R.; Cox, J.; Lieberman, D.; Behrens, P.; Arnett, K.

    1987-01-01

    Algal cultures can be very rapid and efficient means to generate biomass and regenerate the atmosphere for closed environmental life support systems. However, as in the case of most higher plants, a significant fraction of the biomass produced by most algae cannot be directly converted to a useful food product by standard food technology procedures. This waste biomass will serve as an energy drain on the overall system unless it can be efficiently recycled without a significant loss of its energy content. Experiments are reported in which cultures of the alga Scenedesmus obliquus were grown in the light and at the expense of an added carbon source, which either replaced or supplemented the actinic light. As part of these experiments, hydrolyzed waste biomass from these same algae were tested to determine whether the algae themselves could be made part of the biological recycling process. Results indicate that hydrolyzed algal (and plant) biomass can serve as carbon and energy sources for the growth of these algae, suggesting that the efficiency of the closed system could be significantly improved using this recycling process.

  9. Evaluation of various solvent systems for lipid extraction from wet microalgal biomass and its effects on primary metabolites of lipid-extracted biomass.

    Science.gov (United States)

    Ansari, Faiz Ahmad; Gupta, Sanjay Kumar; Shriwastav, Amritanshu; Guldhe, Abhishek; Rawat, Ismail; Bux, Faizal

    2017-06-01

    Microalgae have tremendous potential to grow rapidly, synthesize, and accumulate lipids, proteins, and carbohydrates. The effects of solvent extraction of lipids on other metabolites such as proteins and carbohydrates in lipid-extracted algal (LEA) biomass are crucial aspects of algal biorefinery approach. An effective and economically feasible algae-based oil industry will depend on the selection of suitable solvent/s for lipid extraction, which has minimal effect on metabolites in lipid-extracted algae. In current study, six solvent systems were employed to extract lipids from dry and wet biomass of Scenedesmus obliquus. To explore the biorefinery concept, dichloromethane/methanol (2:1 v/v) was a suitable solvent for dry biomass; it gave 18.75% lipids (dry cell weight) in whole algal biomass, 32.79% proteins, and 24.73% carbohydrates in LEA biomass. In the case of wet biomass, in order to exploit all three metabolites, isopropanol/hexane (2:1 v/v) is an appropriate solvent system which gave 7.8% lipids (dry cell weight) in whole algal biomass, 20.97% proteins, and 22.87% carbohydrates in LEA biomass. Graphical abstract: Lipid extraction from wet microalgal biomass and biorefianry approach.

  10. Shielding property of natural biomass against gamma rays.

    Science.gov (United States)

    Mavi, B; Gurbuz, L F; Ciftci, H; Akkurt, I

    2014-01-01

    Algae and cyanobacteria are capable living under harsh conditions in the natural environments and can develop peculiar survival processes. In order to evaluate radiation shielding properties of green algae; Chlorella vulgaris, Scenedesmus obliquus, and cyanobacteria; Synechococcus sp., Planktothrix limnetica, Microcystis aeruginosa, Arthrospira maxima, Anabaena affinis, Phormidium articulatum, and Pseudoanabaena sp. were cultured in batch systems. Air dried biomass was tested for its high tolerance to gamma-radiations in terms of linear attenuation coefficients. In the present work, the linear and mass attenuation coefficients were measured at photon energies of 1173 and 1332 keV. Protection capacity of some biomass was observed to be higher than a 1-cm thick lead standard for comparison. Gamma ray related protection depends not only to thickness but also to density (g/cm3). Hence the effect of biomass density also was tested and significantly found the tested biomass absorbed more of the incoming energy on a density basis than lead. This paper discusses the a new approach to environmental protection from gamma ray. The findings suggest that the test samples, especially cyanobacteria, have a potential for reducing gamma ray more significantly than lead and can be used as shielding materials.

  11. Photosynthetic sensitivity of phytoplankton to commonly used pharmaceuticals and its dependence on cellular phosphorus status.

    Science.gov (United States)

    Grzesiuk, Malgorzata; Wacker, Alexander; Spijkerman, Elly

    2016-05-01

    Recently pharmaceuticals have become significant environmental pollutants in aquatic ecosystems, that could affect primary producers such as microalgae. Here we analyzed the effect of pharmaceuticals on the photosynthesis of microalgae commonly found in freshwater-two species of Chlorophyceae and a member of the Eustigmatophyceae, via PAM fluorometry. As pharmaceuticals, three medicines often consumed in households were chosen: (i) fluoxetine, an antidepressant, (ii) propranolol, a β-blocker and (iii) ibuprofen, an anti-inflammatory and analgesic medicine. The EC50 for the quantum yield of photosystem II in phytoplankton acclimated to inorganic phosphorus (Pi)-replete and Pi-limited conditions was estimated. Acute toxicity experiments over a 5 h exposure revealed that Nannochloropsis limnetica was the least sensitive to pharmaceuticals in its photosynthetic yield out of all species tested. Although the estimation of sub-lethal effects can be vital in contrast to that of LC50s, the EC50 values in all species and for all medicines were orders of magnitude higher than concentrations found in polluted surface water. Chlamydomonas reinhardtii was the most sensitive to fluoxetine (EC50 of 1.6 mg L(-1)), and propranolol (EC50 of 3 mg L(-1)). Acutodesmus obliquus was most sensitive to ibuprofen (EC50 of 288 mg L(-1)). Additionally, the sensitivity to the pharmaceuticals changed under a Pi-limitation; the green algae became less sensitive to fluoxetine and propranolol. In contrast, Pi-limited algal species were more sensitive to ibuprofen. Our results suggest that the sensitivity of algae to pharmaceuticals is (i) highly compound- and species-specific and (ii) dependent on the cellular P status.

  12. Effect of scenedesmus acuminatus green algae extracts on the development of Candida lipolytic yeast in gas condensate-containing media

    Science.gov (United States)

    Bilmes, B. I.; Kasymova, G. A.; Runov, V. I.; Karavayeva, N. N.

    1980-01-01

    Data are given of a comparative study of the growth and development as well as the characteristics of the biomass of the C. Lipolytica yeast according to the content of raw protein, protein, lipids, vitamins in the B group, and residual hydrocarbons during growth in media with de-aromatized gas-condensate FNZ as the carbon source with aqueous and alcohol extracts of S. acuminatus as the biostimulants. It is shown that the decoction and aqueous extract of green algae has the most intensive stimulating effect on the yeast growth. When a decoction of algae is added to the medium, the content of residual hydrocarbons in the biomass of C. lipolytica yeast is reduced by 4%; the quantity of protein, lipids, thamine and inositol with replacement of the yeast autolysate by the decoction of algae is altered little.

  13. Effects of nitrogen source and concentration on biomass and oil production of a Scenedesmus rubescens like microalga.

    Science.gov (United States)

    Lin, Qiang; Lin, Junda

    2011-01-01

    This investigation examined the effects of nitrogen source and concentration on the ash free dry biomass (AFDB) and oil accumulation and productivity of a Scenedesmusrubescens like alga cultivated in indoor photo-bioreactors and outdoor raceway ponds. Among the nitrogen sources ((NH4)2CO3, urea, NaNO3, urea and NaNO3 mixture), the algae fed with the mixture of urea-N and NaNO3-N had the highest AFDB productivity of 0.539±0.040 g/L/d and the content of fatty acid methyl esters (FAME) (%) fed with (NH4)2CO3-N increased continuously for 17 days and reached 42.94±2.05% in the indoor photo-bioreactors. The content of C18 series (as % of total FAME) was high in all the treatments of nitrogen sources. The algae fed with (NH4)2CO3-N had the highest FAME productivity of 0.133 g/L/d (P<0.001). The effect of ammonia concentration on the AFDB and FAME productivity was also studied during the 20-day cultivation in the outdoor raceway cultivation system. The mean FAME of the algae cultivated in the ammonia concentration of 1.0-1.5 mg/L were the highest (0.556±0.112 g/m2/d) (P<0.001). The total Kjeldahl nitrogen (TKN) in the algae and cultivation water decreased but the FAME content (%) of the algae increased during the nitrogen starvation phase. Copyright © 2010 Elsevier Ltd. All rights reserved.

  14. Enhanced attached growth of microalgae Scenedesmus. LX1 through ambient bacterial pre-coating of cotton fiber carriers.

    Science.gov (United States)

    Zhuang, Lin-Lan; Azimi, Yaldah; Yu, Dawei; Wang, Wen-Long; Wu, Yin-Hu; Dao, Guo-Hua; Hu, Hong-Ying

    2016-10-01

    The role of bacteria/extracellular polymeric substances (EPS) coated carriers on attached microalgae growth in suspended-solid phase photobioreactor (sspBR) was assessed in this study. The results showed that pre-coating cotton with ambient bacteria and their EPS improved the attached microalgal growth by as much as 230% in terms of attached microalgae density. Additionally, the single cell dry weight, chemical composition and oxygen evolving activity of attached microalgae were significantly affected by the presence of bacteria/EPS coating on the cotton carriers. The protein content of microalgae cells cultivated in the ssPBRs with carriers coated by bacteria and sterilized bacteria were on average 26% and 15% more than uncoated carriers, respectively. Through absorbing and immobilizing nutrients from the bulk medium, the bacteria/EPS coating provided the attached microalgae with nitrogen/phosphorus for protein synthesis, especially during the late stages of batch cultivation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Fatty acids composition of 10 microalgal species

    Directory of Open Access Journals (Sweden)

    Thidarat Noiraksar

    2005-11-01

    Full Text Available Fatty acids composition of 10 species of microalgae was determined at the exponential phase and the stationary phase. The microalgae consist of two species of diatoms, Bacillariophyceae, (Nitzschia cf. ovalis, Thalassiosira sp. five species of green microalgae, Prasinophyceae (Tetraselmis sp. and Chlorophyceae, (Dictyosphaerium pulchellum, Stichococcus sp., Chlorella sp., Scenedesmus falcatus and three species of blue green microalgae, Cyanophyceae (Anacystis sp., Synechococcus sp., Synechocystis sp..Medium for culture diatoms and green microalgae was F/2, and BG-11 media was used for Cyanophyceae. The microalgae were cultured beneath light intensity 143 μEm-2s-1, light: dark illustration 12:12 hrs., temperature 28ºC, and salinities 8-30 psu. The microalgae were harvested for analyzing fatty acid by centrivugal machine at 3500 rpm. for 5 min. at temperature 20ºC and stored at -80ºC prior to analysis.Fatty acids composition of microalgae differed from species to species. The majority fatty acids composition of diatoms at the exponential phase and the stationary phase were C16:1n-7 (17.12-31.47% and 28.22-42.02%, C16:0 (13.25-19.61% and 18.83-20.67%, C20:5 n-3 (16.65-26.67% and 11.32-23.68% respectively. The principle fatty acids composition of green microalgae, Prasinophyceae, Tetraselmis sp. were C18:3n-3 (16.17-16.67%, C16:0 (15.33-17.45%, C18:1n-9 (12.25-15.43%, C18:2n-6 (9.66-19.97%. The fatty acids composition of green microalgae, Chlorophyceae, were C18:3 n-3 (20.02-26.49% and 15.35- 30.63%, C16:0 (5.76-17.61% and 11.41-20.03%, C18:2n-6 (4.67-17.54% and 7.48-20.61% respectively. The major amounts of fatty acids content of blue green microalgae were C16:1n-7 (9.28-34.91% and 34.48- 35.04%, C14:0 (13.34-25.96% and 26.69-28.24%, C16:0 (5.89-29.15% and 5.70-16.81% except for Anacystis sp.which had a high amount of C18:3 n-3 (23.18-27.98% but low amount of C14:0 (3.66-4.98%.Bacillariophyceae contained the highest amount of highly unsaturated

  16. Planktonic algae and cyanoprokaryotes as indicators of ecosystem ...

    African Journals Online (AJOL)

    2013-10-07

    Oct 7, 2013 ... Scenedesmus opoliensis P.G. Richter. ✓. Scenedesmus quadricauda Chodat. ✓. Scenedesmus spinosus Chodat. ✓. Scenedesmus tenuispina Chodat. ✓. ✓. ✓. Selenastrum sp. ✓. Sphaerocystis sp. ✓. Staurastrum sp. ✓. Tetraedron caudatum (Corda) Hansgirg. ✓. Tetraedron minimum (A. Braun) Hansgirg.

  17. Use of chlorophyll a fluorescence to detect the effect of microcystins on photosynthesis and photosystem II energy fluxes of green algae.

    Science.gov (United States)

    Perron, Marie-Claude; Qiu, Baosheng; Boucher, Nathalie; Bellemare, François; Juneau, Philippe

    2012-04-01

    The phenomenon of cyanobacteria bloom occurs widely in lakes, reservoirs, ponds and slow flowing rivers. Those blooms can have important repercussions, at once on recreational and commercial activities but also on the health of animals and human beings. Indeed, many species are known to produce toxins which are released in water mainly at cellular death. The cyanotoxin most frequently encountered is the microcystin (MC), a hepatotoxin which counts more than 70 variants. The use of fast tests for the detection of this toxin is thus a necessity for the protection of the ecosystems and the human health. A promising method for their detection is a bioassay based on the chlorophyll a fluorescence of algae. Many studies have shown that algae are sensible to diverse pollutants, but were almost never used for cyanotoxins. Therefore, our goals were to evaluate the effect of microcystin on the fluorescence of different species of algae and how it can affect the flow of energy through photosystem II. To reach these objectives, we exposed four green algae (Scenedesmus obliquus CPCC5, Chlamydomonas reinhardtii CC125, Pseudokirchneriella subcapitata CPCC37 and Chlorella vulgaris CPCC111) to microcystin standards (variants MC-LF, LR, RR, YR) and to microcystin extracted from Microcystis aeruginosa (CPCC299), which is known to produce mainly MC-LR. Chlorophyll a fluorescence was measured by PEA (Plant Efficiency Analyzer) and LuminoTox. The results of our experiment showed that microcystins affect the photosynthetic efficiency and the flow of energy through photosystem II from 0.01 μg/mL, within only 15 min. From exposure to standard of microcystin, we showed that MC-LF was the most potent variant, followed by MC-YR, LR and RR. Moreover, green algae used in this study demonstrated different sensitivity to MCs, S. obliquus being the more sensitive. We finally demonstrated that LuminoTox was more sensitive to MCs than parameters measured with PEA, although the latter brings

  18. The good, the bad and the plenty: interactive effects of food quality and quantity on the growth of different Daphnia species.

    Science.gov (United States)

    Bukovinszky, Tibor; Verschoor, Antonie M; Helmsing, Nico R; Bezemer, T Martijn; Bakker, Elisabeth S; Vos, Matthijs; de Senerpont Domis, Lisette N

    2012-01-01

    Effects of food quality and quantity on consumers are neither independent nor interchangeable. Although consumer growth and reproduction show strong variation in relation to both food quality and quantity, the effects of food quality or food quantity have usually been studied in isolation. In two experiments, we studied the growth and reproduction in three filter-feeding freshwater zooplankton species, i.e. Daphnia galeata x hyalina, D. pulicaria and D. magna, on their algal food (Scenedesmus obliquus), varying in carbon to phosphorus (C∶P) ratios and quantities (concentrations). In the first experiment, we found a strong positive effect of the phosphorus content of food on growth of Daphnia, both in their early and late juvenile development. Variation in the relationship between the P-content of animals and their growth rate reflected interspecific differences in nutrient requirements. Although growth rates typically decreased as development neared maturation, this did not affect these species-specific couplings between growth rate and Daphnia P-content. In the second experiment, we examined the effects of food quality on Daphnia growth at different levels of food quantity. With the same decrease in P-content of food, species with higher estimated P-content at zero growth showed a larger increase in threshold food concentrations (i.e. food concentration sufficient to meet metabolic requirements but not growth). These results suggest that physiological processes such as maintenance and growth may in combination explain effects of food quality and quantity on consumers. Our study shows that differences in response to variation in food quality and quantity exist between species. As a consequence, species-specific effects of food quality on consumer growth will also determine how species deal with varying food levels, which has implications for resource-consumer interactions.

  19. The evolution of glutathione metabolism in phototrophic microorganisms

    Science.gov (United States)

    Fahey, R. C.; Buschbacher, R. M.; Newton, G. L.

    1987-01-01

    Of the many roles ascribed to glutathione (GSH) the one most clearly established is its role in the protection of higher eucaryotes against oxygen toxicity through destruction of thiol-reactive oxygen byproducts. If this is the primary function of GSH then GSH metabolism should have evolved during or after the evolution of oxygenic photosynthesis. That many bacteria do not produce GSH is consistent with this view. In the present study we have examined the low-molecular-weight thiol composition of a variety of phototrophic microorganisms to ascertain how evolution of GSH production is related to evolution of oxygenic photosynthesis. Cells were extracted in the presence of monobromobimane (mBBr) to convert thiols to fluorescent derivatives, which were analyzed by high-pressure liquid chromatography. Significant levels of GSH were not found in the green bacteria (Chlorobium thiosulfatophilum and Chloroflexus aurantiacus). Substantial levels of GSH were present in the purple bacteria (Chromatium vinosum, Rhodospirillum rubrum, Rhodobacter sphaeroides, and Rhodocyclus gelatinosa), the cyanobacteria [Anacystis nidulans, Microcoleus chthonoplastes S.G., Nostoc muscorum, Oscillatoria amphigranulata, Oscillatoria limnetica, Oscillatoria sp. (Stinky Spring, Utah), Oscillatoria terebriformis, Plectonema boryanum, and Synechococcus lividus], and eucaryotic algae (Chlorella pyrenoidsa, Chlorella vulgaris, Euglena gracilis, Scenedesmus obliquus, and Chlamydomonas reinhardtii). Other thiols measured included cysteine, gamma-glutamylcysteine, thiosulfate, coenzyme A, and sulfide; several unidentified thiols were also detected. Many of the organisms examined also exhibited a marked ability to reduce mBBr to syn-(methyl,methyl)bimane, an ability that was quenched by treatment with 2-pyridyl disulfide or 5,5'-bisdithio-(2-nitrobenzoic acid) prior to reaction with mBBr. These observations indicate the presence of a reducing system capable of electron transfer to mBBr and reduction of

  20. Cytotoxicity of TiO{sub 2} nanoparticles and their detoxification in a freshwater system

    Energy Technology Data Exchange (ETDEWEB)

    Dalai, Swayamprava; Pakrashi, Sunandan; Joyce Nirmala, M.; Chaudhri, Apoorvi; Chandrasekaran, N. [Centre for Nanobiotechnology, VIT University, Vellore (India); Mandal, A.B. [Chemical Laboratory, Central Leather Research Institute, Chennai (India); Mukherjee, Amitava, E-mail: amitav@vit.ac.in [Centre for Nanobiotechnology, VIT University, Vellore (India)

    2013-08-15

    Highlights: •TiO{sub 2} NPs cytotoxicity at low exposure levels (≤1 μg/mL) to freshwater algae. •ROS generation, NP adsorption and internalization contributors to toxicity. •Observational evidence of genotoxicity by nanoparticles in an algal cell. •Reduced bioavailability thus detoxification of NPs by microalgae. •Possible role of EPS in detoxification. -- Abstract: In the current study, two aspects concerning (i) the cytotoxicity potential of TiO{sub 2} nanoparticles (NPs) toward freshwater algal isolate Scenedesmus obliquus and (ii) the potential detoxification of NPs by the microalgae were assessed under light (UV-illumination) and dark conditions at low exposure levels (≤1 μg/mL), using sterile freshwater as the test medium. The statistically significant reduction in cell viability, increase in reactive oxygen species production and membrane permeability (light vs. dark) suggested photo-induced toxicity of TiO{sub 2} NPs. The electron micrographs demonstrated adsorption of the NPs onto the cell surface and substantiated their internalization/uptake. The fluorescence micrographs and the confocal laser scanning (CLSM) images suggested the absence of a definite/intact nucleus in the light treated cells pointing toward the probable genotoxic effects of NPs. In a separate three cycle experiment, a continuous decrease in the cytotoxicity was observed, whereas, at the end of each cycle only fresh algae were added to the supernatant containing NPs from the previous cycle. The decreasing concentrations of the NPs in the subsequent cycles owing to agglomeration–sedimentation processes exacerbated by the algal interactions played a crucial role in the detoxification. In addition, the exo-polymeric substances produced by the cells could have rendered the available NPs less reactive, thereby, enhancing the detoxification effects.

  1. The good, the bad and the plenty: interactive effects of food quality and quantity on the growth of different Daphnia species.

    Directory of Open Access Journals (Sweden)

    Tibor Bukovinszky

    Full Text Available Effects of food quality and quantity on consumers are neither independent nor interchangeable. Although consumer growth and reproduction show strong variation in relation to both food quality and quantity, the effects of food quality or food quantity have usually been studied in isolation. In two experiments, we studied the growth and reproduction in three filter-feeding freshwater zooplankton species, i.e. Daphnia galeata x hyalina, D. pulicaria and D. magna, on their algal food (Scenedesmus obliquus, varying in carbon to phosphorus (C∶P ratios and quantities (concentrations. In the first experiment, we found a strong positive effect of the phosphorus content of food on growth of Daphnia, both in their early and late juvenile development. Variation in the relationship between the P-content of animals and their growth rate reflected interspecific differences in nutrient requirements. Although growth rates typically decreased as development neared maturation, this did not affect these species-specific couplings between growth rate and Daphnia P-content. In the second experiment, we examined the effects of food quality on Daphnia growth at different levels of food quantity. With the same decrease in P-content of food, species with higher estimated P-content at zero growth showed a larger increase in threshold food concentrations (i.e. food concentration sufficient to meet metabolic requirements but not growth. These results suggest that physiological processes such as maintenance and growth may in combination explain effects of food quality and quantity on consumers. Our study shows that differences in response to variation in food quality and quantity exist between species. As a consequence, species-specific effects of food quality on consumer growth will also determine how species deal with varying food levels, which has implications for resource-consumer interactions.

  2. Effect of nitrogen-mediated changes in alkalinity on pH control and CO(2) supply in intensive microalgal cultures.

    Science.gov (United States)

    Goldman, J C; Dennett, M R; Riley, C B

    1982-03-01

    The freshwater alga Scenedesmus obliquus was grown in continuous culture at a fixed dilution rate of 0.5/day, but at varying pH in the range 4.17-10.67. The pH was regulated in the range 4.17-7.67 by continuously bubbling 1% CO(2)-enriched air into the cultures and by varying the source of nitrogen (NO(3) (-), NH(4) (+), or urea) in the growth medium, which, in turn, led to changes in culture alkalinity. Culture alkalinity and P(CO(2) ) were the sole determinants of pH. A pH-stat system, together with NO(3) (-) in the medium, was used to regulate the pH in the range 7.92-10.67. Maximum productivity, which occurred at pH 6.6, was dependent on N source only to the extent that culture alkalinity was a function of nitrogen uptake. The results demonstrate that the choice of N is a critical factor in controlling the pH of large-scale algal cultures. NH(4) (+) is a poor source of N because it leads to destruction of culture alkalinity and concomitant growth-inhibiting reductions in pH, whereas NO(3) (-) has an opposite effect, although pH is not so severely affected in this case. Urea is, by far, the most suitable N source for maximizing algal yield when it is supplied in combination with the proper amounts of HCO(3) (-) alkalinity in the growth medium and percent CO(2) in the bubbled gas that will lead to an equilibrium pH near the optimum pH.

  3. Toxicity of ammonia to algae in sewage oxidation ponds.

    Science.gov (United States)

    Abeliovich, A; Azov, Y

    1976-06-01

    Ammonia, at concentrations over 2.0 mM and at pH values over 8.0, inhibits photosynthesis and growth of Scenedesmus obliquus, a dominant species in high-rate sewage oxidation ponds. Photosynthesis of Chlorella pyrenoidosa, Anacystis nidulans, and Plectonema boryanum is also susceptible to ammonia inhibition. Dark respiration and cell morphology were unaffected by any combination of pH and ammonia concentrations tested, thus limiting the apparent effect to inhibition of the normal function of the chloroplasts. Methylamine had the same effect as ammonia, and its penetration into the cells was found to be pH dependent. Therefore, the dependence of toxicity of amines to algae on pH apparently results from the inability to penetrate the cell membrane in the ionized form. When operated at 120-h detention time of raw wastewater, the high-rate oxidation pond maintained a steady state with respect to algal growth and oxygen concentration, and the concentration of ammonia did not exceed 1.0 mM. Shifting the pond to 48-h detention time caused an increase in ammonia concentration in the pond water to 2.5 mM, and the pond gradually turned anaerobic. Photosynthesis, which usually elevates the pH of the pond water to 9.0 to 10.0, could not proceed beyond pH 7.9 because of the high concentration of ammonia, and the algal population was washed out and reduced to a concentration that could maintain a doubling time of 48 h without photosynthesis bringing the pH to inhibitory levels. Under these conditions, the pH of the bond becomes a factor that limits the operational efficiency of the oxidation pond.

  4. The evolution of glutathione metabolism in phototrophic microorganisms.

    Science.gov (United States)

    Fahey, R C; Buschbacher, R M; Newton, G L

    1987-01-01

    Of the many roles ascribed to glutathione (GSH) the one most clearly established is its role in the protection of higher eucaryotes against oxygen toxicity through destruction of thiol-reactive oxygen byproducts. If this is the primary function of GSH then GSH metabolism should have evolved during or after the evolution of oxygenic photosynthesis. That many bacteria do not produce GSH is consistent with this view. In the present study we have examined the low-molecular-weight thiol composition of a variety of phototrophic microorganisms to ascertain how evolution of GSH production is related to evolution of oxygenic photosynthesis. Cells were extracted in the presence of monobromobimane (mBBr) to convert thiols to fluorescent derivatives, which were analyzed by high-pressure liquid chromatography. Significant levels of GSH were not found in the green bacteria (Chlorobium thiosulfatophilum and Chloroflexus aurantiacus). Substantial levels of GSH were present in the purple bacteria (Chromatium vinosum, Rhodospirillum rubrum, Rhodobacter sphaeroides, and Rhodocyclus gelatinosa), the cyanobacteria [Anacystis nidulans, Microcoleus chthonoplastes S.G., Nostoc muscorum, Oscillatoria amphigranulata, Oscillatoria limnetica, Oscillatoria sp. (Stinky Spring, Utah), Oscillatoria terebriformis, Plectonema boryanum, and Synechococcus lividus], and eucaryotic algae (Chlorella pyrenoidsa, Chlorella vulgaris, Euglena gracilis, Scenedesmus obliquus, and Chlamydomonas reinhardtii). Other thiols measured included cysteine, gamma-glutamylcysteine, thiosulfate, coenzyme A, and sulfide; several unidentified thiols were also detected. Many of the organisms examined also exhibited a marked ability to reduce mBBr to syn-(methyl,methyl)bimane, an ability that was quenched by treatment with 2-pyridyl disulfide or 5,5'-bisdithio-(2-nitrobenzoic acid) prior to reaction with mBBr. These observations indicate the presence of a reducing system capable of electron transfer to mBBr and reduction of

  5. Metagenome survey of a multispecies and alga-associated biofilm revealed key elements of bacterial-algal interactions in photobioreactors.

    Science.gov (United States)

    Krohn-Molt, Ines; Wemheuer, Bernd; Alawi, Malik; Poehlein, Anja; Güllert, Simon; Schmeisser, Christel; Pommerening-Röser, Andreas; Grundhoff, Adam; Daniel, Rolf; Hanelt, Dieter; Streit, Wolfgang R

    2013-10-01

    Photobioreactors (PBRs) are very attractive for sunlight-driven production of biofuels and capturing of anthropogenic CO2. One major problem associated with PBRs however, is that the bacteria usually associated with microalgae in nonaxenic cultures can lead to biofouling and thereby affect algal productivity. Here, we report on a phylogenetic, metagenome, and functional analysis of a mixed-species bacterial biofilm associated with the microalgae Chlorella vulgaris and Scenedesmus obliquus in a PBR. The biofilm diversity and population dynamics were examined through 16S rRNA phylogeny. Overall, the diversity was rather limited, with approximately 30 bacterial species associated with the algae. The majority of the observed microorganisms were affiliated with Alphaproteobacteria, Betaproteobacteria, and Bacteroidetes. A combined approach of sequencing via GS FLX Titanium from Roche and HiSeq 2000 from Illumina resulted in the overall production of 350 Mbp of sequenced DNA, 165 Mbp of which was assembled in larger contigs with a maximum size of 0.2 Mbp. A KEGG pathway analysis suggested high metabolic diversity with respect to the use of polymers and aromatic and nonaromatic compounds. Genes associated with the biosynthesis of essential B vitamins were highly redundant and functional. Moreover, a relatively high number of predicted and functional lipase and esterase genes indicated that the alga-associated bacteria are possibly a major sink for lipids and fatty acids produced by the microalgae. This is the first metagenome study of microalga- and PBR-associated biofilm bacteria, and it gives new clues for improved biofuel production in PBRs.

  6. Characterization of the flocculating agent from the spontaneously flocculating microalga Chlorella vulgaris JSC-7.

    Science.gov (United States)

    Alam, Md Asraful; Wan, Chun; Guo, Suo-Lian; Zhao, Xin-Qing; Huang, Zih-You; Yang, Yu-Liang; Chang, Jo-Shu; Bai, Feng-Wu

    2014-07-01

    High cost of biomass recovery is one of the bottlenecks for developing cost-effective processes with microalgae, particularly for the production of biofuels and bio-based chemicals through biorefinery, and microalgal biomass recovery through cell flocculation is a promising strategy. Some microalgae are naturally flocculated whose cells can be harvested by simple sedimentation. However, studies on the flocculating agents synthesized by microalgae cells are still very limited. In this work, the cell flocculation of a spontaneously flocculating microalga Chlorella vulgaris JSC-7 was studied, and the flocculating agent was identified to be cell wall polysaccharides whose crude extract supplemented at low dosage of 0.5 mg/L initiated the more than 80% flocculating rate of freely suspended microalgae C. vulgaris CNW11 and Scenedesmus obliquus FSP. Fourier transform infrared (FTIR) analysis revealed a characteristic absorption band at 1238 cm(-1), which might arise from PO asymmetric stretching vibration of [Formula: see text] phosphodiester. The unique cell wall-associated polysaccharide with molecular weight of 9.86×10(3) g/mol, and the monomers consist of glucose, mannose and galactose with a molecular ratio of 5:5:2. This is the first time to our knowledge that the flocculating agent from C. vulgaris has been characterized, which could provide basis for understanding the cell flocculation of microalgae and breeding of novel flocculating microalgae for cost-effective biomass harvest. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  7. Distribution of heavy metals from flue gas in algal bioreactor

    Science.gov (United States)

    Napan, Katerine

    Flue gas from coal-fired power plants is a major source of CO2 to the atmosphere. Microalgae can use this enriched form of CO2 as carbon source and in turn the biomass can be used to produce food, feed, fertilizer and biofuels. However, along with CO2, coal-based flue gas will inevitably introduce heavy metals, which have a high affinity to bind algal cells, could be toxic to the organisms and if transferred to the products could limit their uses. This study seeks to address the distribution and impact of heavy metals present in flue gas on microalgae production systems. To comprehend its effects, algae Scenedesmus obliquus was grown in batch reactors in a multimetal system. Ten heavy metals (Cu, Co, Zn, Pb, As, Se, Cr, Hg, Ni and Cd) were selected and were evaluated at four concentrations (1X, 2X, 5X and 10X). Results show that most heavy metals accumulated mainly in biomass and were found in very low concentrations in media. Hg was shown to be lost from the culture, with low amounts present in the biomass. An upper limit for As uptake was observed, suggesting its likelihood to build-up in the system during medium recycle. The As limited bioaccumulation was overcome by addition of sulfur to the algal medium. Heavy metal at 2X, 5X and 10X inhibited both growth and lipid production, while at the reference concentration both biomass and lipids yields were increased. Heavy metal concentrations in the medium and biomass were time dependent, and at the end of the cultivation most heavy metals in the supernatant solution complied with the recommendations for irrigation water, while biomass was below limits for cattle and poultry feed, fertilizer, plastic and paper. This research shows that bioremediation of CO2 and heavy metals in combination with energy production can be integrated, which is an environmentally friendly form of biotechnology.

  8. Influence of sodium humate on the growth of Scenedesmus quadricauda (Turp. Brèb. and Gonium pectorale in the case of different calciumand iron doses

    Directory of Open Access Journals (Sweden)

    Krystyna Juraja

    2015-01-01

    Full Text Available The influence of sodium humate on calcium and iron uptake by two species of algae was studied. It was found that sodium humate influence differentially the growth of these algae in various culture conditions by regulating the iron uptake. The action of sodium humate is especially favourable in non optimal pH of the medium and its effectiveness increases with time.

  9. The pH-dependent toxicity of basic pharmaceuticals in the green algae Scenedesmus vacuolatus can be explained with a toxicokinetic ion-trapping model

    Energy Technology Data Exchange (ETDEWEB)

    Neuwoehner, Judith [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Uberlandstr. 133, 8600 Duebendorf (Switzerland); Institute of Biogeochemistry and Pollutant Dynamics (IBP), ETH Zuerich, 8092 Zuerich (Switzerland); Escher, Beate I., E-mail: b.escher@uq.edu.au [The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 39 Kessels Road, Brisbane, QLD 4108 (Australia); Eawag, Swiss Federal Institute of Aquatic Science and Technology, Uberlandstr. 133, 8600 Duebendorf (Switzerland)

    2011-01-17

    Several previous studies revealed that pharmaceuticals with aliphatic amine function exhibit a higher toxicity toward algae than toward other aquatic organisms. Here we investigated the pH-dependent toxicity of the five basic pharmaceuticals fluoxetine, its metabolite norfluoxetine, propranolol, lidocaine, and trimipramine. For all of them, the toxicity increased with increasing pH when aqueous effect concentrations were considered. Since these pharmaceuticals contain a basic amine group that is protonated and thus positively charged at physiological pH and because algae are capable of biological homeostasis, i.e., pH inside the algal cell remains virtually independent of variable external pH, the speciation of aliphatic amines can be different inside the algal cell compared to the external medium. Therefore, we hypothesized that the high toxicity of aliphatic amines in algae is a toxicokinetic effect caused by speciation and not a toxicodynamic effect caused by a specific mode of toxic action. This hypothesis also implies that internal effect concentrations are independent on external pH. On this basis we developed a simple toxicokinetic model, which assumes that only the neutral molecule is bioavailable and can pass the plasma membrane. This assumption is likely to be valid at pH values down to two units below the acidity constant (pK{sub a}). For lower pH values a more complex model would have to be evoked that includes, an, albeit smaller, permeability of the charged species. For pH > pK{sub a} - 2, we can safely assume that the outer membrane serves as insulator and that the charged species is formed inside the cell according to the pH in the cytoplasm. Thus this toxicokinetic model is an ion-trapping model. The input parameters of this model are the measured aqueous effect concentrations determined as a function of pH and the membrane-water partitioning, which was modelled by the liposome-water partition coefficients of the neutral and cationic species. They were deduced from experimentally determined liposome-water distribution ratios at various pH values measured with an equilibrium dialysis method. The modelled internal effect concentrations were independent of the external pH and effective membrane burdens were in the same range as for other baseline toxicants found in the literature for algae, daphnids and fish. These results confirm that the higher algal toxicity of pharmaceuticals with an aliphatic amine group can be explained by a toxicokinetic effect and that these pharmaceuticals do not exhibit a specific mode of action in algae but act as baseline toxicants.

  10. The pH-dependent toxicity of basic pharmaceuticals in the green algae Scenedesmus vacuolatus can be explained with a toxicokinetic ion-trapping model.

    Science.gov (United States)

    Neuwoehner, Judith; Escher, Beate I

    2011-01-17

    Several previous studies revealed that pharmaceuticals with aliphatic amine function exhibit a higher toxicity toward algae than toward other aquatic organisms. Here we investigated the pH-dependent toxicity of the five basic pharmaceuticals fluoxetine, its metabolite norfluoxetine, propranolol, lidocaine, and trimipramine. For all of them, the toxicity increased with increasing pH when aqueous effect concentrations were considered. Since these pharmaceuticals contain a basic amine group that is protonated and thus positively charged at physiological pH and because algae are capable of biological homeostasis, i.e., pH inside the algal cell remains virtually independent of variable external pH, the speciation of aliphatic amines can be different inside the algal cell compared to the external medium. Therefore, we hypothesized that the high toxicity of aliphatic amines in algae is a toxicokinetic effect caused by speciation and not a toxicodynamic effect caused by a specific mode of toxic action. This hypothesis also implies that internal effect concentrations are independent on external pH. On this basis we developed a simple toxicokinetic model, which assumes that only the neutral molecule is bioavailable and can pass the plasma membrane. This assumption is likely to be valid at pH values down to two units below the acidity constant (pK(a)). For lower pH values a more complex model would have to be evoked that includes, an, albeit smaller, permeability of the charged species. For pH>pK(a)-2, we can safely assume that the outer membrane serves as insulator and that the charged species is formed inside the cell according to the pH in the cytoplasm. Thus this toxicokinetic model is an ion-trapping model. The input parameters of this model are the measured aqueous effect concentrations determined as a function of pH and the membrane-water partitioning, which was modelled by the liposome-water partition coefficients of the neutral and cationic species. They were deduced from experimentally determined liposome-water distribution ratios at various pH values measured with an equilibrium dialysis method. The modelled internal effect concentrations were independent of the external pH and effective membrane burdens were in the same range as for other baseline toxicants found in the literature for algae, daphnids and fish. These results confirm that the higher algal toxicity of pharmaceuticals with an aliphatic amine group can be explained by a toxicokinetic effect and that these pharmaceuticals do not exhibit a specific mode of action in algae but act as baseline toxicants. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Microflora de Bromeliáceas do estado de Pernambuco, Brasil

    Directory of Open Access Journals (Sweden)

    Luis Tavares de Lyra

    1976-01-01

    Full Text Available O autor estudou a microflora de dois gêneros de BROMELIACEAE: Hoenbergia e Portea. As coletas do material foram feitas em seis regiões do Estado de Pernambuco; 1 Região da Mata-Úmida; 2 Região da Mata-Seca; 3 Região do Agreste Central; 4 Região do Agreste Setentrional; 5 Região do Agreste Meridional; 6 Região do Recife. As seguintes diatomáceas indicadoras de águas poluídas (espécies oligossaprobias foram encontradas nas seis regiões estudadas: Gomphonema parvulum (Kutz Grunow., Hantzschia amphioxys Grunow, Pinnularia borealis Ehr., Pinnularia microstauron (Ehr Cleve, gomphonema gracile Ehr., Nitzschia palea Kutz., Melosira roeseana Rabenh., Navicula mutica Kutz., Navicula cryptocephala Kutz., Eunotia pectinalis (Kutz Rabenh. Foram também observadas CHLOROPHYCEAS nas estações chuvosa e seca nas diversas regiões. Algumas são indicadoras de oligossaprobidade: Scenedesmus quadricauda (Turpin brebisson. Chlorococcum sp., Chlorella sp. Os fatores ecológicos e comentários referentes ás diatomáceas foram anotados no texto. A tabela I indica a frequência das diatomáceas nas seis regiões estudadas. Maior número dessas diatomáceas, registramos nas regiões do Agreste. A tabela II mostra a temperatura e pH da água de Hoenbergia e Portea em ambas as estações do ano (inverno e verão. Observamos a ocorrência de larvas de culex em Portea e hoenbergia, entretanto, raramente encontramos larvas de Anopheles. As coletas foram feitas durante as estações chuvosa e seca em Hoenbergia e Portea. Determinamos 35 espécies provenientes de 78 amostras coletadas durante o período de 26 meses.The author studied the microflora from two genera of Bromeliaceae: Hoenbergia and Portea. The material was collected in six natural regions of Pernambuco State: 1 Humid Forest Region; 2 Dry forest region; 3 Central Agreste Region; 4 Setentrional Agreste Region; 5 Meridional Agreste Region; 6 Recife Region. The following diatoms that indicate polluted

  12. Untitled

    Indian Academy of Sciences (India)

    , by Krause. Since then more and more algae from the Chlorophyceae,. Chrysophyceae ... butions in this new and fascinating field of research are reviewed here with a view to understand the full import of these investigations into the micro-.

  13. Bioactivity of marine organisms. 6. Antiviral evaluation of marine algal extracts from the Indian coast

    Digital Repository Service at National Institute of Oceanography (India)

    Kamat, S.Y.; Wahidullah, S.; DeSouza, L.; Naik, C.G.; Ambiye, V.; Bhakuni, D.S.; Goel, A.K.; Garg, H.S.; Srimal, R.C.

    Ethanolic extracts of Indian marine algae belonging to the Rhodophyceae, Phaeophyceae and Chlorophyceae were tested for anti-semiliki Forest (SFV), Ranikhet Disease (RDV) and Vaccinia (VV) viruses. In the primary screening of 31 seaweeds, 17...

  14. Bioactivity of marine organisms: Part 7- Effect of seaweed extract on central nervous system

    Digital Repository Service at National Institute of Oceanography (India)

    Kamat, S.Y.; Wahidullah, S.; DeSouza, L.; Naik, C.G.; Ambiye, V.; Bhakuni, D.S.; Jain, S.; Goel, A.K.; Srimal, R.C.

    Alcohol extracts of marine algae (Rhodophyceae, Phaeophyceae and Chlorophyceae) was screened for their effect on central nervous system. Of 69 species investigated 8 appeared biologically active, 6 being CNS stimulant, sites and dates of collection...

  15. U.S. Air Force Installation Restoration Program. Phase 1. Records Search. Air National Guard, Camp Edwards (ARNG), U.S. Air Force and Veteran’s Administration Facilities at Massachusetts Military Reservation, Massachusetts. Appendices: Task 6

    Science.gov (United States)

    1986-12-11

    Biology, 1978 Certifications Habitat Evaluation Procedures (HEP) Certificate, 1984 Associations Maine Association of Planners New England Association of...Chlorophyceae (Greens) Coelastrum sp. 28 Sphaerocystis sp. 364 .0 Staurastrum sp. 28 Subtotal 420 Cryptophyceae ( Cryptomonads ) Cryptomonas sp. 56 Subtotal

  16. Screening of antioxidant activity in microalgae

    Directory of Open Access Journals (Sweden)

    Mariana F.G. Assunção

    2014-06-01

    Both sets of results indicate an interesting antioxidant potential in microalgae belonging to the groups Eustigmatophyceae and Chlorophyceae. Tested species of these groups showed ABTS•+ values comparable to grape and raspberry ethanolic extracts, confirmed also by the DPPH• method.

  17. Physico-Chemical Parameters and Phytoplankton Community of ...

    African Journals Online (AJOL)

    These were Bacilliariophyceae, Cyanophyceae and Chlorophyceae. The phytoplankton community was predominated by Cyanophyceae which constituted more than 40% of the total phytoplankton population. The predominant taxa were Spirulina sp., Lepocindis sp., Merimospedia sp., Anabena sp. and Coclastrum sp.

  18. Biochemical constituents of seaweeds along the Maharashtra coast

    Digital Repository Service at National Institute of Oceanography (India)

    Dhargalkar, V.K.; Jagtap, T.G.; Untawale, A.G.

    Protein, carbohydrate and organic carbon were estimated in 43 marine algal species from different stations along the Maharashtra Coast in India These species showed variation in their biochemical contents Protein varied from 10 to 33% Chlorophyceae...

  19. The laboratory environmental algae pond simulator (LEAPS) photobioreactor: Validation using outdoor pond cultures of Chlorella sorokiniana and Nannochloropsis salina

    Energy Technology Data Exchange (ETDEWEB)

    Huesemann, M.; Williams, P.; Edmundson, S.; Chen, P.; Kruk, R.; Cullinan, V.; Crowe, B.; Lundquist, T.

    2017-09-01

    A bench-scale photobioreactor system, termed Laboratory Environmental Algae Pond Simulator (LEAPS), was designed and constructed to simulate outdoor pond cultivation for a wide range of geographical locations and seasons. The LEAPS consists of six well-mixed glass column photobioreactors sparged with CO2-enriched air to maintain a set-point pH, illuminated from above by a programmable multicolor LED lighting (0 to 2,500 µmol/m2-sec), and submerged in a temperature controlled water-bath (-2 °C to >60 °C). Measured incident light intensities and water temperatures deviated from the respective light and temperature set-points on average only 2.3% and 0.9%, demonstrating accurate simulation of light and temperature conditions measured in outdoor ponds. In order to determine whether microalgae strains cultured in the LEAPS exhibit the same linear phase biomass productivity as in outdoor ponds, Chlorella sorokiniana and Nannochloropsis salina were cultured in the LEAPS bioreactors using light and temperature scripts measured previously in the respective outdoor pond studies. For Chlorella sorokiniana, the summer season biomass productivity in the LEAPS was 6.6% and 11.3% lower than in the respective outdoor ponds in Rimrock, Arizona, and Delhi, California; however, these differences were not statistically significant. For Nannochloropsis salina, the winter season biomass productivity in the LEAPS was statistically significantly higher (15.2%) during the 27 day experimental period than in the respective outdoor ponds in Tucson, Arizona. However, when considering only the first 14 days, the LEAPS biomass productivity was only 9.2% higher than in the outdoor ponds, a difference shown to be not statistically significant. Potential reasons for the positive or negative divergence in LEAPS performance, relative to outdoor ponds, are discussed. To demonstrate the utility of the LEAPS in predicting productivity, two other strains – Scenedesmus obliquus and Stichococcus minor

  20. Gain and loss of polyadenylation signals during evolution of green algae

    Directory of Open Access Journals (Sweden)

    Glöckner Gernot

    2007-04-01

    Full Text Available Abstract Background The Viridiplantae (green algae and land plants consist of two monophyletic lineages: the Chlorophyta and the Streptophyta. Most green algae belong to the Chlorophyta, while the Streptophyta include all land plants and a small group of freshwater algae known as Charophyceae. Eukaryotes attach a poly-A tail to the 3' ends of most nuclear-encoded mRNAs. In embryophytes, animals and fungi, the signal for polyadenylation contains an A-rich sequence (often AAUAAA or related sequence 13 to 30 nucleotides upstream from the cleavage site, which is commonly referred to as the near upstream element (NUE. However, it has been reported that the pentanucleotide UGUAA is used as polyadenylation signal for some genes in volvocalean algae. Results We set out to investigate polyadenylation signal differences between streptophytes and chlorophytes that may have emerged shortly after the evolutionary split between Streptophyta and Chlorophyta. We therefore analyzed expressed genes (ESTs from three streptophyte algae, Mesostigma viride, Klebsormidium subtile and Coleochaete scutata, and from two early-branching chlorophytes, Pyramimonas parkeae and Scherffelia dubia. In addition, to extend the database, our analyses included ESTs from six other chlorophytes (Acetabularia acetabulum, Chlamydomonas reinhardtii, Helicosporidium sp. ex Simulium jonesii, Prototheca wickerhamii, Scenedesmus obliquus and Ulva linza and one streptophyte (Closterium peracerosum. Our results indicate that polyadenylation signals in green algae vary widely. The UGUAA motif is confined to late-branching Chlorophyta. Most streptophyte algae do not have an A-rich sequence motif like that in embryophytes, animals and fungi. We observed polyadenylation signals similar to those of Arabidopsis and other land plants only in Mesostigma. Conclusion Polyadenylation signals in green algae show considerable variation. A new NUE (UGUAA was invented in derived chlorophytes and replaced