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Sample records for microalga scenedesmus obliquus

  1. Microalga Scenedesmus obliquus as a potential source for biodiesel production

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Shovon; Mallick, Nirupama [Indian Inst. of Technology, Kharagpur, West Bengal (India). Agricultural and Food Engineering Dept.

    2009-08-15

    Biodiesel from microalgae seems to be the only renewable biofuel that has the potential to completely replace the petroleum-derived transport fuels. Therefore, improving lipid content of microalgal strains could be a cost-effective second generation feedstock for biodiesel production. Lipid accumulation in Scenedesmus obliquus was studied under various culture conditions. The most significant increase in lipid reached 43% of dry cell weight (dcw), which was recorded under N-deficiency (against 12.7% under control condition). Under P-deficiency and thiosulphate supplementation the lipid content also increased up to 30% (dcw). Application of response surface methodology in combination with central composite rotary design (CCRD) resulted in a lipid yield of 61.3% (against 58.3% obtained experimentally) at 0.04, 0.03, and 1.0 g l{sup -1} of nitrate, phosphate, and sodium thiosulphate, respectively for time culture of 8 days. Scenedesmus cells pre-grown in glucose (1.5%)-supplemented N 11 medium when subjected to the above optimized condition, the lipid accumulation was boosted up to 2.16 g l{sup -1}, the value {proportional_to}40-fold higher with respect to the control condition. The presence of palmitate and oleate as the major constituents makes S. obliquus biomass a suitable feedstock for biodiesel production. (orig.)

  2. "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

  3. The kinetics of Scenedesmus obliquus microalgae growth utilizing carbon dioxide gas from biogas

    International Nuclear Information System (INIS)

    Thiansathit, Worrarat; Keener, Tim C.; Khang, Soon-Jai; Ratpukdi, Thunyalux; Hovichitr, Patcharee

    2015-01-01

    Microalgae Scenedesmus obliquus was cultured in a laboratory photobioreactor to determine the efficacy of using biogas as a carbon source for the microalgae's growth. The biogas contained ∼60% CH 4 and ∼40% CO 2 , and was derived from an anaerobic digester operating from animal wastes, and an anaerobic reactor utilizing high strength wastewater. The results showed that biogas is a viable carbon source for microalgae growth and that significant portions of the biogas' CO 2 can be utilized for algae growth, resulting in a biogas having a high concentration of methane. This paper develops the kinetic expressions for the algae's growth by assuming an autocatalytic reaction between carbon substrate and microalgae. The maximum specific growth rate and biomass productivity of S. obliquus were 0.56 d −1 and 0.145 g L −1 d −1 respectively. The biomass contained 51.8% carbon and higher heating value (HHV) was 22.9 MJ kg −1 . - Highlights: • Biogas is a viable carbon source for microalgae growth. • Biomass production rate and characteristics were assessed. • Scenedesmus obliquus can adjust to grow with high concentration of CO 2 in the carbon source

  4. Pilot cultivation of the chlorophyte microalga Scenedesmus obliquus as a promising feedstock for biofuel

    International Nuclear Information System (INIS)

    Abomohra, Abd El-Fatah; El-Sheekh, Mostafa; Hanelt, Dieter

    2014-01-01

    Scenedesmus obliquus was discussed by phycologists as a promising microalga for biofuel production based on its biomass and fatty acid productivity. In the present study, S. obliquus was pilot cultivated for large scale production in a semicontinuous culture for 3 months using polyethylene transparent bags. Cultivation of S. obliquus resulted in a maximum biomass productivity of 0.14 g L −1  d −1 and maximum esterified fatty acid productivity of 17.37 mg L −1  d −1 at light intensity of 130 μmol m −2  s −1 . Using of different flocculants for biomass harvest showed maximum flocculation efficiency of 82% using 250 mg L −1 of NaOH for 2 h. Drying of the harvested biomass showed significant increase of esterified fatty acid content by 5 and 7% with respect to control at 75 and 100 °C, respectively. In addition, fatty acid profile and iodine number of S. obliquus oil meet biodiesel standard specifications which make the fatty acid of S. obliquus eligible for further research to be used as a feedstock for biofuel production. Furthermore, the present investigation showed that after oil extraction, the residual algal biomass increased survival and fresh weight of Artemia (brine shrimp) which confirms that the residual algal biomass can be significantly used as food additives for animal feeding. - Highlights: • Scenedesmus obliquus was cultivated in plastic bags in a semicontinuous culture for high biomass production. • Different flocculants were used for harvesting of S. obliquus and the oil was chemically extracted. • The residual algal biomass was used for feeding of Artemia. • The annual productivity of EFA from S. obliquus would be nearly 5 times higher than Jatropha. • The residual algal biomass increased survival and fresh weight of Artemia

  5. 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.

  6. 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.

  7. 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

  8. Enhancement of lipid extraction for improved biodiesel recovery from the biodiesel promising microalga Scenedesmus obliquus

    International Nuclear Information System (INIS)

    Abomohra, Abd El-Fatah; Jin, Wenbiao; El-Sheekh, Mostafa

    2016-01-01

    Highlights: • Chloroform:methanol 2:1 showed the highest lipid extraction efficiency. • Prolongation of extraction time over 2 h showed insignificant effect on EFAs yield and significantly increased FFAs. • Cell-disruption is not essential for lipid extraction from S. obliquus cells. • Hot-water treatment for 5 min showed significant increase in EFAs yield. - Abstract: During the transesterification of oil feedstock for biodiesel production, the reaction primarily happens at the ester bonds where the fatty acid chains meet the glycerol. Therefore, only esterified fatty acids (EFAs) are able to be turned directly into biodiesel by transesterification. In this study, an optimized procedure for EFAs recovery from the biodiesel promising microalga Scenedesmus obliquus was studied. The effect of different solvent mixtures (ratios), extraction times, pretreatments and cell-disruption methods on intracellular EFAs and free fatty acids (FFAs) yield was examined. Using of chloroform:methanol (C:M) 2:1 for 2 h was shown to be the best solvent mixture for lipid extraction which resulted in the highest EFAs yield. Furthermore, testing of different cell-disruption methods showed that cell-disruption is not essential for lipid extraction from S. obliquus cells. Although, microwave pretreatment showed significant increase in EFAs yield with respect to overnight oven drying at 80 °C, all showed insignificant differences to the control. Moreover, overnight cell freezing showed 7.7% significant reduction in EFAs yield with respect to the control, while hot-water treatment for 5 min showed significant increase by 13.7%. On the other hand, overnight cell incubation, in oven or freezing, resulted in significant increase in FFAs up to 7.44 and 12.47 mg g"−"1 of the dry weight, respectively. In addition, the present study showed that no pretreatment with isopropanol to inactivate the lipases is needed when hot-water pretreatment is performed. This study suggested that hot

  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

  10. Using microalgae scenedesmus obliquus in the removal of chromium present in plating wastewaters; Empleo de microalga scenedesmus obliquus en la eliminaciond e cromo presente en aguas residuales galvanicas

    Energy Technology Data Exchange (ETDEWEB)

    Pellon, A.; Benitez, F.; Frades, J.; Garcia, L.; Cerpa, A.; Alguacil, F. J.

    2003-07-01

    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 citiplasmatic structures with no-toxic effects. Microalgaehave 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%. (Author) 19 refs.

  11. Using microalgae scenedesmus obliquus in the removal of chromium present in plating wastewaters

    International Nuclear Information System (INIS)

    Pellon, A.; Benitez, F.; Frades, J.; Garcia, L.; Cerpa, A.; Alguacil, F.

    2003-01-01

    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 citiplasmatic structures with no-toxic effects. Microalgaehave 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%. (Author) 19 refs

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Harvesting of freshwater microalgae Scenedesmus obliquus and Chlorella vulgaris using acid mine drainage as a cost effective flocculant for biofuel production

    International Nuclear Information System (INIS)

    Salama, El-Sayed; Jeon, Byong-Hun; Kurade, Mayur B.; Abou-Shanab, Reda A.I.; Govindwar, Sanjay P.; Lee, Sang-hun; Yang, Il-Seung; Lee, Dae Sung

    2016-01-01

    Graphical abstract: Schematic presentation of coagulation/flocculation of microalgal biomass using AMD. - Highlights: • AMDs containing high Fe"2"+/Al"3"+ improved the settling kinetics of microalgal biomass. • The highest k_2 value was 40 × 10"−"2 L mg"−"1 min"−"1 for C. vulgaris with AMD (1). • With AMD (2), k_2 was 4.0 × 10"−"2 L mg"−"1 min"−"1 for both C. vulgaris and S. obliquus. • The highest FE (93%) and CF (29) for C. vulgaris was achieved with AMD (1). • AMD (1) removed 99.80% of Fe"3"+ and 99.99% of Al"3"+ from the supernatant. - Abstract: Development of a low-cost harvesting technology could be an effective approach for making microalgal biofuel commercially feasible. The use of acid mine drainage (AMD) to coagulate/flocculate biomass is a cost-effective strategy for addressing this challenge. Here, settling kinetics, flocculation efficiency (FE), and concentration factor (CF) of two morphologically different microalgae species, Scenedesmus obliquus and Chlorella vulgaris, were investigated with respect to AMD dosage (5% and 10%) and medium pH (7 and 9). AMD was collected from two different sites, AMD (1) and AMD (2), and increasing its dosage to 10% improved the settling rate, FE, and CF of the floc. At 10% AMD (1) dosage and pH 9, the highest rate constants (k_2) for the second order equations were 6.65 × 10"−"2 and 40 × 10"−"2 L mg"−"1⋅min"−"1 for S. obliquus and C. vulgaris, respectively; at 10% AMD (2), k_2 values were 4.22 × 10"−"2 and 4.76 × 10"−"2 L mg"−"1 min"−"1, respectively. Similarly, FE/CF values were 89%/25 for S. obliquus and 93%/29 for C. vulgaris with 10% AMD (1); and 81%/17 and 79%/17, respectively, with 10% AMD (2). AMD effectively removed 99.80% of Fe"3"+, 99.99% of Al"3"+, 94% of Ca"2"+, 84% of Mg"2"+ and all of Na"+ and K"+ ions from the supernatant. The results of kinetics, EF, and CF measurements indicate that AMDs, naturally rich in iron and aluminum ions, could provide a feasible

  17. 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

  18. 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.

  19. 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.

  20. Plutonium sorption by the green algae Scenedesmus obliquus (Tuerp) Kuetz

    International Nuclear Information System (INIS)

    Tkacik, M.F.; Giesy, J.P.; Corey, J.C.

    1978-01-01

    As part of the continuing study of the possible impact of released radioisotopes to the Savannah River Plant (SRP) environment, the interaction between a biological system and plutonium was investigated. Specifically, an algal culture, Scenedesmus obliquus, was exposed to the +4 and +6 oxidation states of 238 Pu and 239-240 Pu at three plutonium concentration levels. There was no significant different (p 3) 0.05) between 238 Pu and 239-240 Pu accumulation by the algae at equivalent concentrations or at different oxidation states

  1. 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.

  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. 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.

  4. 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.

  5. Anaerobic digestibility of Scenedesmus obliquus and Phaeodactylum tricornutum under mesophilic and thermophilic conditions

    International Nuclear Information System (INIS)

    Zamalloa, Carlos; Boon, Nico; Verstraete, Willy

    2012-01-01

    Highlights: ► We investigate the digestion of two algae biomasses in hybrid flow-through reactors. ► We determine the bio-methane potential of these biomasses through batch assays. ► Conversion efficiencies of 20–50% with an HRT of 2.2 days are possible. ► We valorise microalgae biomass by anaerobic digestion in a high rate reactor. -- Abstract: Two types of non-axenic algal cultures, one dominated by the freshwater microalgae Scenedesmus obliquus and the other by the marine microalgae Phaeodactylum tricornutum, were cultivated in two types of simple photobioreactor systems. The production rates, expressed on dry matter (DM) basis, were in the order of 0.12 and 0.18 g DM L −1 d −1 for S. obliquus and P. tricornutum respectively. The biogas potential of algal biomass was assessed by performing standardized batch digestion as well as digestion in a hybrid flow-through reactor (combining a sludge blanket and a carrier bed), the latter under mesophilic and thermophilic conditions. Biomethane potential assays revealed the ultimate methane yield (B 0 ) of P. tricornutum biomass to be about a factor of 1.5 higher than that of S. obliquus biomass, i.e. 0.36 and 0.24 L CH 4 g −1 volatile solids (VS) added respectively. For S. obliquus biomass, the hybrid flow-through reactor tests operated at volumetric organic loading rate (Bv) of 2.8 gVS L −1 d −1 indicated low conversion efficiencies ranging between 26–31% at a hydraulic retention time (HRT) of 2.2 days for mesophilic and thermophilic conditions respectively. When digesting P. tricornutum at a Bv of 1.9 gVS L −1 d −1 at either mesophilic or thermophilic conditions and at an HRT of 2.2 days, an overall conversion efficiency of about 50% was obtained. This work indicated that the hydrolysis of the algae cells is limiting the anaerobic processing of intensively grown S. obliquus and P. tricornutum biomass.

  6. 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.

  7. 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.)

  8. Bioethanol production from Scenedesmus obliquus sugars: the influence of photobioreactors and culture conditions on biomass production.

    Science.gov (United States)

    Miranda, J R; Passarinho, P C; Gouveia, L

    2012-10-01

    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.

  9. Plutonium uptake by Scenedesmus obliquus as a function of isotope and oxidation state

    International Nuclear Information System (INIS)

    Tkacik, M.F.; Giesy, J.P.; Wilhite, E.L.; Corey, J.C.

    1979-01-01

    Uptake of 238 Pu 4+ , 238 Pu 6+ , 239 Pu 4+ and 239 Pu 6+ by the green alga Scenedesmus obliquus (Turp) Kutz was studied to determine whether isotope or oxidation state differences affect Pu uptake from aqueous medium by algal cells. At equivalent 238 Pu and 239 PU concentrations, even when initial oxidation states differed, accumulations of these isotopes by S.obliquus were not significantly (p>0.05) different. Plutonium accumulation by S.obliquus was log-linear. (author)

  10. 60Co retention by a freshwater planktonic alga Scenedesmus obliquus

    International Nuclear Information System (INIS)

    Nucho, R.; Baudin, J.P.

    1989-01-01

    This paper presents the results of various decontamination experiments aimed at evaluating 60 Co retention by Scenedesmus obliquus, and the respective role played by absorption and adsorption in the contamination of the alga by this radionuclide. The physiological condition of cells is not involved in radiocobalt desorption, which seems to indicate that the phenomenon is of a passive nature. When the precontamination time is extended, the proportion of adsorbed 60 Co decreases, and the final percentage of radionuclide retained increases. These results are confirmed by bringing cells into contact with a strong chelating agent. The elimination of 60 Co in the presence of EDTA undergoes a sharp decrease which is correlated with the increase in the duration of the precontamination phase. The use of a weaker complexing agent, such as NaCl, leads to the hypothesis of there being 2 types of 60 Co receptor on cell membranes. (author)

  11. 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.

  12. 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 IC 50 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.

  13. 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.

  14. 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.

  15. 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.

  16. Effect of phosphorus on biodiesel production from Scenedesmus obliquus under nitrogen-deficiency stress.

    Science.gov (United States)

    Chu, Fei-Fei; Chu, Pei-Na; Shen, Xiao-Fei; Lam, Paul K S; Zeng, Raymond J

    2014-01-01

    In order to study the effect of phosphorus on biodiesel production from Scenedesmus obliquus especially under nitrogen deficiency conditions, six types of media with combinations of nitrogen repletion/depletion and phosphorus repletion/limitation/depletion were investigated in this study. It was found that nitrogen starvation compared to nitrogen repletion enhanced biodiesel productivity. Moreover, biodiesel productivity was further strengthened by varying the supply level of phosphorus from depletion, limitation, through to repletion. The maximum FAMEs productivity of 24.2 mg/L/day was obtained in nitrogen depletion with phosphorus repletion, which was two times higher than that in nutrient complete medium. More phosphorus was accumulated in cells under the nitrogen starvation with sufficient phosphorus condition, but no polyphosphate was formed. This study indicated that nitrogen starvation plus sufficient P supply might be the real "lipid trigger". Furthermore, results of the current study suggest a potential application for utilizing microalgae to combine phosphorus removal from wastewater with biodiesel production. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. 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.

  18. 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.

  19. Uptake of tritiated lysine by fresh water alga, Scenedesmus obliquus

    International Nuclear Information System (INIS)

    Gogate, S.S.; Krishnamoorthy, T.M.

    1983-01-01

    Tritium uptake by fresh water alga. S.obliquus was studied using tritium labelled lysine, and a sequential solvent extraction procedure was used to study the distribution of tritium in different organic constituents of the algal cells. The accumulation of tritium in the algal cells was found to be 3-4 orders of magnitude more than that obtained for tritiated water. (author)

  20. Influence of light presence and biomass concentration on nutrient kinetic removal from urban wastewater by Scenedesmus obliquus.

    Science.gov (United States)

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

    2014-05-20

    This work was aimed at studying the effect of light-darkness and high-low biomass concentrations in the feasibility of removing nitrogen and phosphorus from urban treated wastewater by the microalga Scenedesmus obliquus. Laboratory experiments were conducted in batch, where microalgae were cultured under different initial biomass concentrations (150 and 1500mgSSl(-1)) and light conditions (dark or illuminated). Nutrient uptake was more dependent on internal nutrient content of the biomass than on light presence or biomass concentration. When a maximum nitrogen or phosphorus content in the biomass was reached (around 8% and 2%, respectively), the removal of that nutrient was almost stopped. Biomass concentration affected more than light presence on the nutrient removal rate, increasing significantly with its increase. Light was only required to remove nutrients when the maximum nutrient storage capacity of the cells was reached and further growth was therefore needed. Residence times to maintain a stable biomass concentration, avoiding the washout of the reactor, were much higher than those needed to remove the nutrients from the wastewater. This ability to remove nutrients in the absence of light could lead to new configurations of reactors aimed to wastewater treatment. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Biodegradation of phenanthrene by the green alga scenedesmus obliquus ES-55

    Energy Technology Data Exchange (ETDEWEB)

    Safonova, E.; Kvitko, K. [Biological Institute of St. Petersburg State University, Oranienbaum Chaussee 2, Old Peterhof, 198504 St. Petersburg (Russian Federation); Kuschk, P.; Moeder, M. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Permoserstrasse 15, Leipzig (Germany); Reisser, W. [Universitaet Leipzig, Botanisches Institut, Johannisallee 21-23, D-04103 Leipzig (Germany)

    2005-06-01

    While the degradation of polycyclic aromatic hydrocarbons by bacteria and fungi has been broadly investigated, less is known about the metabolism of these compounds by algae. The goal of the experiments was to test the degradability of phenanthrene by the green alga Scenedesmus obliquus ES-55 (Chlorophyceae) and to identify the metabolites. It was shown that S. obliquus ES-55 metabolized phenanthrene. Under light conditions, phenanthrene (14 mg/L) inhibits cell division by more than twice. However, the metabolic processes in the cells affected by phenanthrene continued because the content of chlorophyll increased. In the exponential phase under phototrophic conditions the alga degraded phenanthrene. Phenanthrene was removed by algae up to 42 % in BBM medium and up to 24 % in Kuhl medium. Dihydroxy-dihydro-phenanthrene, a degradation metabolite in fungi, bacteria and cyanobacteria, could also be detected as a transformation product of S. obliquus ES-55. Further detected common metabolites foster the assumption that both phototrophic and non-photothrophic organisms metabolize phenanthrene via a similar pathway. The present study is the first evidence of the ability of an axenic culture of the green alga S. obliquus to biotransform phenanthrene into other metabolites. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  2. 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.

  3. 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.

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

    International Nuclear Information System (INIS)

    Geoffroy, Laure; Frankart, Cecile; Eullaffroy, Philippe

    2004-01-01

    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 50 for growth rate. In L. minor, the sensitivity of the parameters was as follows: Q N >Oxygen emission>PHIs PSII >Q P >PHI PSII >CAT, GR>Pigment>APO>Growth. For S. obliquus, this ranking was as follows: CAT>Oxygen emission>Q P >APO>GR>Pigment>PHIs PSII >Growth>PHI PSII >Q 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

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. 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)

  10. 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.

  11. 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.

  12. 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

    2016-01-01

    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. PMID:26868157

  13. Biological effect of aqueous C60 aggregates on Scenedesmus obliquus revealed by transcriptomics and non-targeted metabolomics.

    Science.gov (United States)

    Du, Chunlei; Zhang, Bo; He, Yiliang; Hu, Chaoyang; Ng, Qin Xiang; Zhang, Hui; Ong, Choon Nam; ZhifenLin

    2017-02-15

    This work evaluated biological effect of nC 60 on Scenedesmus obliquus. The cells were exposed to various concentrations of nC 60 for 7days. Low-dose of nC 60 was found to have a minor growth inhibitory effect. The transcriptomics and metabolomics were integrated to examine intricate molecular and cellular effects of nC 60 on Scenedesmus obliquus. We found that Scenedesmus obliquus cells exposed to nC 60 had several significant alterations in cellular transcription and biochemical processes. During the 7-day exposure to nC 60 , 2234 and 2,448 unigenes were differentially expressed by 0.1mg/L and 1mg/L nC 60 -treated groups compared with the control, including 2085 or 2247 up-regulated genes and 149 or 201 down-regulated genes, respectively. We successfully identified 22 metabolites, including 6 significantly changed metabolites, such as sucrose, d-glucose, and malic acid. The citrate cycle (TCA cycle) (ko00020) was the main target of both differentially expressed genes and metabolic change. However, accumulation of sucrose (end-product) could have induced feedback inhibition of photosynthesis in Scenedesmus obliquus, explaining the slight growth inhibition observed. The results provided a mechanistic understanding of the growth inhibition of nC 60 toxicity. These genes and metabolites are useful biomarkers for future studies and offer new insights into the early detectable changes in Scenedesmus obliquus with nC 60 exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Mechanisms of60Co uptake and loss by Scenedesmus obliquus and transfer to two benthic organisms

    International Nuclear Information System (INIS)

    Nucho, R.

    1989-10-01

    The affinity of Scenedesmus obliquus for 60 Co has been confirmed under various experimental conditions allowing for the age of cultures, the physiological state of the cells, the radioactivity level and stable cobalt concentration in the medium, and the acute or periodic nature of the contamination. The dry weight 60 Co concentration factor may reach 4x10 4 in LCO culture medium and is about 10 4 in natural water. 60 Co uptake by algae is a 95% passive phenomenon, initiated by radionuclide absorption on the cell walls and followed by intracellular diffusion in accordance with Fick's law. From the initial cationic form, radiocobalt develops anion forms at a rate proportional to the algal biomass, resulting in lower contamination of old and dense cultures. After transfer in natural or artificial nonradioctive medium, 60 Co is eliminated by Scenedesmus obliquus, mainly as Co 2+ ions, according to a two-phase exponential process with two biological half-lives. The study of radioactive cobalt transfer from algae to gammarids and to midge larvae reveals the extend to which phytoplankton predominate over water and sediment in contaminating these two organisms. The total 60 Co uptake depends significantly on whether the cells are incorporated in or deposited on the sediment. No biomagnification phenomenon of the radionuclide was found in any case, as the transfer factor was less than 1. Depuration of 60 Co by organisms involved a two-phase exponential process regardless of whether uptake occured directly or from food. The presence of sediment appears to reduce the 60 Co desorption rate, but from 85 to 95% of the initial quantity is eliminated. This percentage does not depend on the transfer pathway or the presence of organic matter, and indicates very slight assimilation of radiocobalt ingested with algal cells [fr

  19. 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

  20. 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.

  1. 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

  2. Contamination of a green algae (Scenedesmus obliquus) from fresh water by radionuclides typical of PWR effluents: culture in a turbidostat

    International Nuclear Information System (INIS)

    Sombre, L.; Carraro, S.; Myttenaere, C.

    1987-01-01

    The fixation of radioactive polluents, typical for PWR effluents, by the green soft water algae Scenedesmus obliquus is studied by means of a continuous culture method and in controlled conditions (turbidostat). Transfer factors are obtained. The elimination of radiocesium occurs in two distinct phases characterized respectively by a short biological period of less than one hour and a long period of the order of one day. The photosynthetic metabolism of the algae accounts for 25% of the decorporation. (Author)

  3. Effects of naturally occurring aquatic organic fractions on 241Am uptake by Scenedesmus obliquus (Chlorophyceae) and Aeromonas hydrophila (Pseudomonadaceae)

    International Nuclear Information System (INIS)

    Giesy, J.P. Jr.; Paine, D.

    1977-01-01

    Naturally occurring organics were extracted from water collected from Skinface Pond near Aiken, S.C. Organics were separated into four nominal diameter size fractions (I, greater than 0.0183; II, 0.0183 to 0.0032; III, 0.0032 to 0.0009; IV, less than 0.0009 μm) by membrane ultrafiltration and introduced into Scenedesmus obliquus and Aeromonas hydrophila cultures to determine their effects on 241 Am availability for uptake. Effects on 241 Am uptake were determined in actively growing S. obliquus cultures after 96 h of growth and in dense cultures of nongrowing cells after 4 h. Uptake by A. hydrophila was determined after 4 and 24 h in actively growing cultures. All organic fractions stimulated S. obliquus growth, with the most pronounced effects due to larger organic fractions, whereas no apparent growth stimulation of A. hydrophila was observed for any organic fraction. For both long-term and short-term studies, cellular 241 Am concentration (picocuries/cell) increased with increasing 241 Am concentration for S. obliquus and A. hydrophila. Fraction IV increased 241 Am uptake by both S. obliquus and A. hydrophila during 4-h incubations. During 96-h incubations fraction I was flocculated and cosedimented, with S. obliquus and A. hydrophila cells causing an apparent increase in 241 Am uptake. Fractions II and III reduced apparent 241 Am uptake by S. obliquus as a result of biological dilution caused by increased algal growth due to the organics. Fraction IV caused a reduction in 241 Am uptake by S. obliquus not attributable to biological dilution. Organics increased 241 Am uptake by A. hydrophila during 4- and 24-h incubations. A. hydrophila also caused flocculation of fraction I during 96-h incubations

  4. Bioaccumulation and effects of novel chlorinated polyfluorinated ether sulfonate in freshwater alga Scenedesmus obliquus.

    Science.gov (United States)

    Liu, Wei; Li, Jingwen; Gao, Lichen; Zhang, Zhou; Zhao, Jing; He, Xin; Zhang, Xin

    2018-02-01

    Chlorinated polyfluorinated ether sulfonate (Cl-PFESA) is a novel alternative compound for perfluorooctane sulfonate (PFOS), with its environmental risk not well known. The bioaccumulation and toxic effects of Cl-PFESA in the freshwater alga is crucial for the understanding of its potential hazards to the aquatic environment. Scenedesmus obliquus was exposed to Cl-PFESA at ng L -1 to mg L -1 , with the exposure regime beginning at the environmentally relevant level. The total log BAF of Cl-PFESA in S. obliquus was 4.66, higher than the reported log BAF of PFOS in the freshwater plankton (2.2-3.2). Cl-PFESA adsorbed to the cell surface accounted for 33.5-68.3% of the total concentrations. The IC50 of Cl-PFESA to algal growth was estimated to be 40.3 mg L -1 . Significant changes in algal growth rate and chlorophyll a/b contents were observed at 11.6 mg L -1 and 13.4 mg L -1 of Cl-PFESA, respectively. The sample cell membrane permeability, measured by the fluorescein diacetate hydrolyzation, was increased by Cl-PFESA at 5.42 mg L -1 . The mitochondrial membrane potential, measured by Rh123 staining, was also increased, indicating the hyperpolarization induced by Cl-PFESA. The increasing ROS and MDA contents, along with the enhanced SOD, CAT activity, and GSH contents, suggested that Cl-PFESA caused oxidative damage in the algal cells. It is less possible that current Cl-PFESA pollution in surface water posed obvious toxic effects on the green algae. However, the bioaccumulation of Cl-PFESA in algae would contribute to its biomagnification in the aquatic food chain and its effects on membrane property could potentially increase the accessibility and toxicity of other coexisting pollutants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. 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.

  6. 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.

  7. 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).

  8. Validation of photosynthetic-fluorescence parameters as biomarkers for isoproturon toxic effect on alga Scenedesmus obliquus

    Energy Technology Data Exchange (ETDEWEB)

    Dewez, David; Didur, Olivier; Vincent-Heroux, Jonathan [University of Quebec in Montreal, Department of Chemistry, Environmental Toxicology Research Center - TOXEN, 2101, Jeanne-Mance, Montreal, Quebec H2X 2J6 (Canada); Popovic, Radovan [University of Quebec in Montreal, Department of Chemistry, Environmental Toxicology Research Center - TOXEN, 2101, Jeanne-Mance, Montreal, Quebec H2X 2J6 (Canada)], E-mail: popovic.radovan@uqam.ca

    2008-01-15

    Photosynthetic-fluorescence parameters were investigated to be used as valid biomarkers of toxicity when alga Scenedesmus obliquus was exposed to isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea] effect. Chlorophyll fluorescence induction of algal cells treated with isoproturon showed inactivation of photosystem II (PSII) reaction centers and strong inhibition of PSII electron transport. A linear correlation was found (R{sup 2} {>=} 0.861) between the change of cells density affected by isoproturon and the change of effective PSII quantum yield ({phi}{sub M'}), photochemical quenching (q{sub P}) and relative photochemical quenching (q{sub P(rel)}) values. The cells density was also linearly dependent (R{sup 2} = 0.838) on the relative unquenched fluorescence parameter (UQF{sub (rel)}). Non-linear correlation was found (R{sup 2} = 0.937) only between cells density and the energy transfer efficiency from absorbed light to PSII reaction center (ABS/RC). The order of sensitivity determined by the EC-50% was: UQF{sub (rel)} > {phi}{sub M'} > q{sub P} > q{sub P(rel)} > ABS/RC. Correlations between cells density and those photosynthetic-fluorescence parameters provide supporting evidence to use them as biomarkers of toxicity for environmental pollutants. - Photosynthetic-fluorescence parameters are reliable biomarkers of isoproturon toxicity.

  9. Validation of photosynthetic-fluorescence parameters as biomarkers for isoproturon toxic effect on alga Scenedesmus obliquus

    International Nuclear Information System (INIS)

    Dewez, David; Didur, Olivier; Vincent-Heroux, Jonathan; Popovic, Radovan

    2008-01-01

    Photosynthetic-fluorescence parameters were investigated to be used as valid biomarkers of toxicity when alga Scenedesmus obliquus was exposed to isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea] effect. Chlorophyll fluorescence induction of algal cells treated with isoproturon showed inactivation of photosystem II (PSII) reaction centers and strong inhibition of PSII electron transport. A linear correlation was found (R 2 ≥ 0.861) between the change of cells density affected by isoproturon and the change of effective PSII quantum yield (Φ M' ), photochemical quenching (q P ) and relative photochemical quenching (q P(rel) ) values. The cells density was also linearly dependent (R 2 = 0.838) on the relative unquenched fluorescence parameter (UQF (rel) ). Non-linear correlation was found (R 2 = 0.937) only between cells density and the energy transfer efficiency from absorbed light to PSII reaction center (ABS/RC). The order of sensitivity determined by the EC-50% was: UQF (rel) > Φ M' > q P > q P(rel) > ABS/RC. Correlations between cells density and those photosynthetic-fluorescence parameters provide supporting evidence to use them as biomarkers of toxicity for environmental pollutants. - Photosynthetic-fluorescence parameters are reliable biomarkers of isoproturon toxicity

  10. 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.

  11. Validation of photosynthetic-fluorescence parameters as biomarkers for isoproturon toxic effect on alga Scenedesmus obliquus.

    Science.gov (United States)

    Dewez, David; Didur, Olivier; Vincent-Héroux, Jonathan; Popovic, Radovan

    2008-01-01

    Photosynthetic-fluorescence parameters were investigated to be used as valid biomarkers of toxicity when alga Scenedesmus obliquus was exposed to isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea] effect. Chlorophyll fluorescence induction of algal cells treated with isoproturon showed inactivation of photosystem II (PSII) reaction centers and strong inhibition of PSII electron transport. A linear correlation was found (R2>or=0.861) between the change of cells density affected by isoproturon and the change of effective PSII quantum yield (PhiM'), photochemical quenching (qP) and relative photochemical quenching (qP(rel)) values. The cells density was also linearly dependent (R2=0.838) on the relative unquenched fluorescence parameter (UQF(rel)). Non-linear correlation was found (R2=0.937) only between cells density and the energy transfer efficiency from absorbed light to PSII reaction center (ABS/RC). The order of sensitivity determined by the EC-50% was: UQF(rel)>PhiM'>qP>qP(rel)>ABS/RC. Correlations between cells density and those photosynthetic-fluorescence parameters provide supporting evidence to use them as biomarkers of toxicity for environmental pollutants.

  12. 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.

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

    International Nuclear Information System (INIS)

    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 238 Pu and 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 238 Pu or 239 Pu in either Pu +4 or Pu +6 oxidation state at the concentrations studied

  14. Removal of pharmaceutical pollutants from synthetic wastewater using chemically modified biomass of green alga Scenedesmus obliquus.

    Science.gov (United States)

    Ali, Mohamed E M; Abd El-Aty, Azza M; Badawy, Mohamed I; Ali, Rizka K

    2018-04-30

    Pharmaceutical compounds are considered emerging environmental pollutants that have a potential harmful impact on environment and human health. In this study, the biomass of alga (Scenedesmus obliquus) was modified using alkaline solution, and used for the biosorption of tramadol (TRAM) and other pharmaceuticals. The adsorption kinetics and isotherms were investigated. The obtained results reveal high adsorption capacity of tramadol over modified algal biomass (MAB) after 45min with removal percentage of 91%. Pseudo-second order model was well fitted with the experimental data with correlation coefficient (0.999). Biosorption of tramadol on modified algal biomass proceeds with Freundlich isotherm model with correlation coefficient (0.942) that emphasized uptake of TRAM by MAB is driven by chemisorption. FTIR spectra of MAB before and after the adsorption were analyzed; some IR bands were detected with slight shift and low intensity suggesting their involving in adsorption. The tramadol biosorption by MAB is a chemical process as confirmed by Dubinin-Radushkevich. The adsorption of pharmaceutical over MAB is mainly preceded by hydrophilic interactions between amino and carbonyl groups in pharmaceutical molecules and hydroxyl and carbonyl functional groups on surface of biosorbent. It was emphasized by disappearance O-H and C-O from biomass IR spectra after adsorption. In matrix of pharmaceutical, the recorded adsorption capacities for CEFA, PARA, IBU, TRAM and CIP are 68, 58, 42, 42 and 39mg/g over MAB at natural pH and MAB dose of 0.5g/L. Furthermore, oxygen uptake by bacteria was applied for estimate the toxicity of pharmaceutical. The recorded result concluded the efficient reusability of modified algal biomass for biosorption of pharmaceuticals, as well only the adsorption efficiency decreased by 4.5% after three runs. Subsequently, the modified algal biomass is a promising reusable adsorbent for decontamination of wastewater from pharmaceuticals. Copyright

  15. Uptake and effect of highly fluorescent silver nanoclusters on Scenedesmus obliquus.

    Science.gov (United States)

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

    2016-06-01

    The release of silver nanoparticles (Ag NPs) in aquatic environment has caused wide public concern about their effects on living organisms (e.g., algae). However, how these small NPs exert cytotoxicity in the living organisms has always been under heated debate. In this study, the uptake and toxicity effects of strongly red-emitting fluorescent silver nanoclusters (r-Ag NCs) exposed to the green algae Scenedesmus obliquus was investigated. Upon exposure to pure r-Ag NCs and r-Ag NCs containing l-cysteine, the algae growth inhibition test showed that Ag(+) ions released from r-Ag NCs played an important role in the toxicity of r-Ag NCs along with the toxicity of intact r-Ag NCs. Furthermore, no signals of intracellular reactive oxygen species (ROS) were observed indicating that r-Ag NCs or released Ag(+) ions - mediated growth inhibition of algae cells was independent of ROS production. Transmission electron microscopy (TEM) and laser scanning confocal microscopy (LSCM) were employed to study cellular uptake and cytotoxicity. Furthermore, analysis of differential expressed gene demonstrated that r-Ag NCs as well as the released Ag(+) ions can simultaneously exist inside the algae cells, and inhibit the transcriptomic process of genes by their "joint-toxicity" mechanism. Taken together, our study provides a new insight into the molecular mechanisms of r-Ag NCs and Ag(+) ions exposure to the aquatic organism and can be applied to early diagnosis of ecologic risk mediated by others metal-based NPs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. 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

  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. 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

    2016-01-01

    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 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. PMID:27294942

  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. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 1H NMR studies of plastocyanin from Scenedesmus obliquus: Complete sequence-specific assignment, secondary structure analysis, and global fold

    International Nuclear Information System (INIS)

    Moore, J.M.; Chazin, W.J.; Wright, P.E.; Powls, R.

    1988-01-01

    Two-dimensional 1 H NMR methods have been used to make sequence-specific resonance assignments for the 97 amino acid residues of the plastocyanin from the green alga Scenedesmus obliquus. Assignments were obtained for all backbone protons and the majority of the side-chain protons. Spin system identification relied heavily on the observation of relayed connectivities to the backbone amide proton. Sequence-specific assignments were made by using the sequential assignment procedure. During this process, an extra valine residue was identified that had not been detected in the original amino acid sequence. Elements of regular secondary structure were identified from characteristic NOE connectivities between backbone protons, coupling constant values, and the observation of slowly exchanging amide protons. The protein in solution contains eight β-strands, one short segment of helix, five reverse turns, and five loops. The β-strands may be arranged into two βsheets on the basis of extensive cross-strand NOE connectivities. The chain-folding topology determined from the NMR experiments is that of a Greek key β-barrel and is similar to that observed for French bean plastocyanin in solution and poplar plastocyanin in the crystalline state. While the overall structures are similar, several differences in local structure between the S. obliquus and higher plant plastocyanins have been identified

  6. 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.

  7. Determination of photosynthetic and enzymatic biomarkers sensitivity used to evaluate toxic effects of copper and fludioxonil in alga Scenedesmus obliquus

    International Nuclear Information System (INIS)

    Dewez, David; Geoffroy, Laure; Vernet, Guy; Popovic, Radovan

    2005-01-01

    Modulated PAM fluorometry and Plant Efficiency Analyser methods were used to investigate photosynthetic fluorescence parameters of alga Scenedesmus obliquus exposed to inhibitory effect of fungicides copper sulphate and fludioxonil (N-(4-nitrophenyl)-N'-propyl-uree). The change of those parameters were studied when alga S. obliquus have been exposed during 48 h to different concentrations of fungicides (1, 2 and 3 mg l -1 ). Under the same condition, enzymatic activities of catalase, ascorbate peroxidase, glutathione reductase and glutathione S-transferase were investigated to evaluate antioxidative response to fungicides effects. The change of sensitivity of those parameters was dependent to the mode of fungicide action, their concentration and time of exposure. For copper effects, the most indicative photosynthetic biomarkers were parameters Q N as non-photochemical fluorescence quenching, Q Emax as the proton induced fluorescence quenching and ABS/RC as the antenna size per photosystem II reaction center. Copper induced oxidative stress was indicated by increased activity of catalase serving as the most sensitive and valuable enzymatic biomarker. On the other hand, fludioxonil effect on photosynthetic parameters was very negligible and consequently not very useful as biomarkers. However, fludioxonil induced strong antioxidative activities associated with cytosol enzymes, as we found for catalase, ascorbate peroxidase and glutathione S-transferase activities. By obtained results, we may suggest for the activation of those enzymes to be sensitive and valuable biomarkers of oxidative stress induced by fludioxonil. Determination of biomarkers sensitivity may offer advantages in providing real criteria to use them for ecotoxicological diagnostic studies

  8. Effect of ionic liquids with different cations and anions on photosystem and cell structure of Scenedesmus obliquus.

    Science.gov (United States)

    Xia, Yilu; Liu, Dingdong; Dong, Ying; Chen, Jiazheng; Liu, Huijun

    2018-03-01

    The rapid increase in the production and practical application of ionic liquids (ILs) could pose potential threats to aquatic systems. In this study, we investigated the effects of four ILs with different cations and anions, including 1-hexyl-3-methylimidazolium nitrate ([HMIM]NO 3 ), 1-hexyl-3-methylimidazolium chloride ([HMIM]Cl), N-hexyl-3-metylpyridinium chloride ([HMPy]Cl), and N-hexyl-3-metylpyridinium bromide ([HMPy]Br), on photosystem and cellular structure of Scenedesmus obliquus. The results indicated that ILs are phytotoxic to S. obliquus. The contents of chlorophyll a, chlorophyll b and total chlorophyll decreased with increasing ILs concentrations. The chlorophyll fluorescence parameters of photosynthetic system II (PSII), including minimal fluorescence yield (F 0 ), potential efficiency of PSII (F v /F o ), maximum quantum efficiency of PSII photochemistry (F v /F m ), yield of photochemical quantum [Y(II)], and non-photochemical quenching coefficient without measuring F 0 ' (NPQ), were all affected. This indicates that ILs could damage PSII, inhibit the primary reaction of photosynthesis, interdict the process of electron-transfer and lead to loss of heat-dissipating ability. ILs also increased cell membrane permeability of S. obliquus, influenced the cellular ultrastructure, changed the morphology of algae cells and destroyed the cell wall, cell membrane and organelles. The results indicated that imidazolium ILs had greater effect than pyridinium ILs, NO 3 - -IL and Br - -IL had greater effect than Cl - -IL. To minimize threats to the environment, the structure of ILs should be taken into consideration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Investigations on the isoprenoid biosynthesis in the green alga Scenedesmus obliquus by using the 13C-labelling technique

    International Nuclear Information System (INIS)

    Schwender, J.

    1995-01-01

    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 13 C-labelled glucose or acetate. After isolation and purification of 13 C-labelled phytol (side chains of chlorophylls), β-carotene, lutein, plastoquinone-9 and three sterol compounds, the enrichment of 13 C at different carbon-positions of the labelled compounds was determined. This was achieved by the 13 C-NMR technique in cooperation with Miriam Seemann of the group of Prof. M. Rohmer in Mullhouse/France. (orig.) [de

  10. 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.

  11. Determination of photosynthetic and enzymatic biomarkers sensitivity used to evaluate toxic effects of copper and fludioxonil in alga Scenedesmus obliquus

    Energy Technology Data Exchange (ETDEWEB)

    Dewez, David [Departement de Chimie et de Biochimie, Centre TOXEN, Universite du Quebec a Montreal, CP 8888, Succursale Centre-Ville, Montreal, Quebec, H3C 3P8 (Canada); Geoffroy, Laure [Laboratoire d' Eco-Toxicologie, Unite de recherche ' Vignes et Vins de Champagne' , UPRES-EA 2069, Universite de Reims Champagne-Ardenne BP 1039, F51687 REIMS CEDEX 2 (France); Vernet, Guy [Laboratoire d' Eco-Toxicologie, Unite de recherche ' Vignes et Vins de Champagne' , UPRES-EA 2069, Universite de Reims Champagne-Ardenne BP 1039, F51687 REIMS CEDEX 2 (France); Popovic, Radovan [Departement de Chimie et de Biochimie, Centre TOXEN, Universite du Quebec a Montreal, CP 8888, Succursale Centre-Ville, Montreal, Quebec, H3C 3P8 (Canada)]. E-mail: popovic.radovan@uqam.ca

    2005-08-30

    Modulated PAM fluorometry and Plant Efficiency Analyser methods were used to investigate photosynthetic fluorescence parameters of alga Scenedesmus obliquus exposed to inhibitory effect of fungicides copper sulphate and fludioxonil (N-(4-nitrophenyl)-N'-propyl-uree). The change of those parameters were studied when alga S. obliquus have been exposed during 48 h to different concentrations of fungicides (1, 2 and 3 mg l{sup -1}). Under the same condition, enzymatic activities of catalase, ascorbate peroxidase, glutathione reductase and glutathione S-transferase were investigated to evaluate antioxidative response to fungicides effects. The change of sensitivity of those parameters was dependent to the mode of fungicide action, their concentration and time of exposure. For copper effects, the most indicative photosynthetic biomarkers were parameters Q {sub N} as non-photochemical fluorescence quenching, Q {sub Emax} as the proton induced fluorescence quenching and ABS/RC as the antenna size per photosystem II reaction center. Copper induced oxidative stress was indicated by increased activity of catalase serving as the most sensitive and valuable enzymatic biomarker. On the other hand, fludioxonil effect on photosynthetic parameters was very negligible and consequently not very useful as biomarkers. However, fludioxonil induced strong antioxidative activities associated with cytosol enzymes, as we found for catalase, ascorbate peroxidase and glutathione S-transferase activities. By obtained results, we may suggest for the activation of those enzymes to be sensitive and valuable biomarkers of oxidative stress induced by fludioxonil. Determination of biomarkers sensitivity may offer advantages in providing real criteria to use them for ecotoxicological diagnostic studies.

  12. 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.

  13. Comparative study of zooid and non-zooid forming strains of Scenedesmus obliquus. Physiology and cytomorphology

    Czech Academy of Sciences Publication Activity Database

    Cepák, Vladislav; Přibyl, Pavel; Kvíderová, Jana; Lukavský, Jaromír

    2006-01-01

    Roč. 51, č. 4 (2006), s. 349-356 ISSN 0015-5632 R&D Projects: GA ČR(CZ) GA204/03/1113; GA MŠk(CZ) 1M0571 Institutional research plan: CEZ:AV0Z60050516 Keywords : physiology * zooids * Scenedesmus Subject RIV: EF - Botanics Impact factor: 0.963, year: 2006

  14. Lipid content and fatty acid composition of green algae Scenedesmus obliquus grown in a constant cell density apparatus

    Science.gov (United States)

    Choi, K. J.; Nakhost, Z.; Barzana, E.; Karel, M.

    1987-01-01

    The lipids of alga Scenedesmus obliquus grown under controlled conditions were separated and fractionated by column and thin-layer chromatography, and fatty acid composition of each lipid component was studied by gas-liquid chromatography (GLC). Total lipids were 11.17%, and neutral lipid, glycolipid and phospholipid fractions were 7.24%, 2.45% and 1.48% on a dry weight basis, respectively. The major neutral lipids were diglycerides, triglycerides, free sterols, hydrocarbons and sterol esters. The glycolipids were: monogalactosyl diglyceride, digalactosyl diglyceride, esterified sterol glycoside, and sterol glycoside. The phospholipids included: phosphatidyl choline, phosphatidyl glycerol and phosphatidyl ethanolamine. Fourteen fatty acids were identified in the four lipid fractions by GLC. The main fatty acids were C18:2, C16:0, C18:3(alpha), C18:1, C16:3, C16:1, and C16:4. Total unsaturated fatty acid and essential fatty acid compositions of the total algal lipids were 80% and 38%, respectively.

  15. UVΑ pre-irradiation to P25 titanium dioxide nanoparticles enhanced its toxicity towards freshwater algae Scenedesmus obliquus.

    Science.gov (United States)

    Roy, Barsha; Chandrasekaran, Hemamalini; Palamadai Krishnan, Suresh; Chandrasekaran, Natarajan; Mukherjee, Amitava

    2018-04-02

    There has recently been an increase in the usage of TiO 2 nanoparticles (NPs). P25 TiO 2 NPs, a mixture of anatase and rutile phase in 3:1 ratio, are generally used for photocatalytic applications because both phases exhibit a synergistic effect on the photocatalytic activity of the TiO 2 NPs. In the present study, increased toxicity of UVA-pre-irradiated P25 TiO 2 NPs on freshwater algae Scenedesmus obliquus was assessed under visible light and dark exposure conditions at actual low concentrations (0.3, 3 and 35 μM of Ti). Photocatalytic property of P25 TiO 2 NPs caused disaggregation of UVA-pre-irradiated NPs, thus significantly decreasing the mean hydrodynamic diameter (MHD) (188.74 ± 0.54 nm) than that of non-irradiated NPs (232.26 ± 0.44). This decrease in diameter of UVA-pre-irradiated NPs may increase its biological activity towards algal samples. All concentrations of pre-irradiated NPs, under both light and dark conditions, showed a significantly lesser cell viability (p effects of UVA-pre-irradiated TiO 2 NPs on freshwater algae, thereby emphasising the need for ecological risk assessments of metal oxide nanoparticles in a natural experimental medium.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. Bioenergetic reprogramming plasticity under nitrogen depletion by the unicellular green alga Scenedesmus obliquus.

    Science.gov (United States)

    Papazi, Aikaterini; Korelidou, Anna; Andronis, Efthimios; Parasyri, Athina; Stamatis, Nikolaos; Kotzabasis, Kiriakos

    2018-03-01

    Simultaneous nitrogen depletion and 3,4-dichlorophenol addition induce a bioenergetic microalgal reprogramming, through strong Cyt b 6 f synthesis, that quench excess electrons from dichlorophenol's biodegradation to an overactivated photosynthetic electron flow and H 2 -productivity. Cellular energy management includes "rational" planning and operation of energy production and energy consumption units. Microalgae seem to have the ability to calculate their energy reserves and select the most profitable bioenergetic pathways. Under oxygenic mixotrophic conditions, microalgae invest the exogenously supplied carbon source (glucose) to biomass increase. If 3,4-dichlorophenol is added in the culture medium, then glucose is invested more to biodegradation rather than to growth. The biodegradation yield is enhanced in nitrogen-depleted conditions, because of an increase in the starch accumulation and a delay in the establishment of oxygen-depleted conditions in a closed system. In nitrogen-depleted conditions, starch cannot be invested in PSII-dependent and PSII-independent pathways for H 2 -production, mainly because of a strong decrease of the cytochrome b 6 f complex of the photosynthetic electron flow. For this reason, it seems more profitable for the microalga under these conditions to direct the metabolism to the synthesis of lipids as cellular energy reserves. Nitrogen-depleted conditions with exogenously supplied 3,4-dichlorophenol induce reprogramming of the microalgal bioenergetic strategy. Cytochrome b 6 f is strongly synthesized (mainly through catabolism of polyamines) to manage the electron bypass from the dichlorophenol biodegradation procedure to the photosynthetic electron flow (at the level of PQ pool) and consequently through cytochrome b 6 f and PSI to hydrogenase and H 2 -production. All the above showed that the selection of the appropriate cultivation conditions is the key for the manipulation of microalgal bioenergetic strategy that leads to

  2. 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.

  3. 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.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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.

  6. 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.

  7. 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..

  8. FATTY ACID ETHYL ESTERS FROM MICROALGAE OF Scenedesmus ecornis BY ENZYMATIC AND ACID CATALYSIS

    Directory of Open Access Journals (Sweden)

    Gabryelle F. de Almeida

    Full Text Available Microalgae are an indispensable food source for the various growth stages of mollusks, crustaceans, and several fish species. Using a microalgae biomass present in the Amazonian ecosystem (Macapá-AP, we study extraction methods for fatty acid such as solvent extraction (magnetic stirring and/or Soxhlet and/or hydrolysis (acid and/or enzymatic catalysis followed by esterification and/or direct transesterification. Extraction of crude triacylglycerides by mechanical stirring at room temperature was more efficient than continuous reflux (Soxhlet. Subsequently, the lipid extract was subject to transesterification with ethanol and CAL-B as a biocatalyst, leading to production of fatty acid ethyl esters (FAEE. Additionally, FAEEs were prepared by hydrolysis of crude triacylglycerides followed by acid-mediated esterification or enzymatic catalysis (lipase. In this case, the type of catalyst did not significantly influence FAEE yields. In the lipid extract, we identified palmitic, linoleic, oleic, and stearic acids with palmitic acid being the most abundant. Our results suggest that enzymatic catalysis is a viable method for the extraction of lipids in the microalga, Scenedesmus ecornis.

  9. 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.

  10. Biosynthetic pathways to delta-aminolevulinic acid induced by blue light in the pigment mutant C-2A' of Scenedesmus obliquus

    International Nuclear Information System (INIS)

    Klein, O.; Senger, H.

    1978-01-01

    The X-ray induced mutant C-2A' of Scenedesmus obliquus grows heterotrophically but forms only traces of chlorophyll in the dark. Upon illumination, delta-aminolevulinic acid (ALA) is synthesized and chlorophyll is formed. These processes are blue light dependent and ceased immediately when the cells were transferred back into darkness. Addition of levulinic acid (LA) inhibited the light-dependent formation of chlorophyll and caused accumulation of ALA by competitive inhibition of the ALA dehydratase (EC. 4.2.1.24). By feeding specifically labelled 14 C precursors to the pigment mutant, inhibiting the ALA dehydratase with LA, accumulating, extracting and analyzing the ALA, two pathways leading towards ALA could be established: glycine and succinyl CoA can be condensed to ALA and the 5 carbon skeleton of glutamate can completely be incorporated into ALA via a second pathway. The glycine-succinyl CoA pathway dominated over the glutamate pathway, but both led to chlorophyll formation. (author)

  11. 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.

  12. 13C-nuclear magnetic resonance studies of the biosynthesis of 5-aminolevolinic acid destined for chlorophyll formation in dark-grown Scenedesmus Obliquus

    International Nuclear Information System (INIS)

    Oh-hama, Tamiko; Seto, Harvo; Miyachi, Shigetoh

    1985-01-01

    The 13 C-nuclear magnetic resonance (NMR) spectra of chlorophyll-α-formed in dark-grown Scenedesmus Obliquus (Turp.) Kutzing in the presence of (1- 13 C) glutamate, (2- 13 C) and (1- 13 C) glycine showed that the 13 C of glutamate was specifically incorporated into the eight-carbon atoms in the tetrapyrrole macrocyles derived from C-5 of 5-aminolevolinic acid (ALA), while the C-2 of glycine was only incorporated into the methyl carbon of the methoxycarbonyl group attached to the isolcyclic ring of chlorophyll a formed in the presence of (1- 13 C)-glycine. These labelling patterns provide evidence for the operation of the C 5 -pathway and against the operation of the ALA synthase pathway for chlorophyll formation in darkness. (author)

  13. 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.

  14. 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.

  15. Thorium (IV) toxicity of green microalgae from Scenedesmus and Monoraphidium genera

    International Nuclear Information System (INIS)

    Queiroz, Juliana Cristina de

    2009-01-01

    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 5 microorganisms/mL reached a final concentration of 5.52x10 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 6 microorganisms/mL. Control tests indicated a final concentration of 2.51x10 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 5 microorganisms/mL reached a final concentration of 2.25x10 6 microorganisms/mL, in the absence of thorium in the medium. Toxicological tests indicated a final culture concentration of 5.87x10 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 one can conclude, that the presence

  16. 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.

  17. 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

  18. 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.

  19. The Complete Mitochondrial DNA Sequence of Scenedesmus obliquus Reflects an Intermediate Stage in the Evolution of the Green Algal Mitochondrial Genome

    Science.gov (United States)

    Nedelcu, Aurora M.; Lee, Robert W.; Lemieux, Claude; Gray, Michael W.; Burger, Gertraud

    2000-01-01

    Two distinct mitochondrial genome types have been described among the green algal lineages investigated to date: a reduced–derived, Chlamydomonas-like type and an ancestral, Prototheca-like type. To determine if this unexpected dichotomy is real or is due to insufficient or biased sampling and to define trends in the evolution of the green algal mitochondrial genome, we sequenced and analyzed the mitochondrial DNA (mtDNA) of Scenedesmus obliquus. This genome is 42,919 bp in size and encodes 42 conserved genes (i.e., large and small subunit rRNA genes, 27 tRNA and 13 respiratory protein-coding genes), four additional free-standing open reading frames with no known homologs, and an intronic reading frame with endonuclease/maturase similarity. No 5S rRNA or ribosomal protein-coding genes have been identified in Scenedesmus mtDNA. The standard protein-coding genes feature a deviant genetic code characterized by the use of UAG (normally a stop codon) to specify leucine, and the unprecedented use of UCA (normally a serine codon) as a signal for termination of translation. The mitochondrial genome of Scenedesmus combines features of both green algal mitochondrial genome types: the presence of a more complex set of protein-coding and tRNA genes is shared with the ancestral type, whereas the lack of 5S rRNA and ribosomal protein-coding genes as well as the presence of fragmented and scrambled rRNA genes are shared with the reduced–derived type of mitochondrial genome organization. Furthermore, the gene content and the fragmentation pattern of the rRNA genes suggest that this genome represents an intermediate stage in the evolutionary process of mitochondrial genome streamlining in green algae. [The sequence data described in this paper have been submitted to the GenBank data library under accession no. AF204057.] PMID:10854413

  20. The complete chloroplast genome sequence of the chlorophycean green alga Scenedesmus obliquus reveals a compact gene organization and a biased distribution of genes on the two DNA strands

    Science.gov (United States)

    de Cambiaire, Jean-Charles; Otis, Christian; Lemieux, Claude; Turmel, Monique

    2006-01-01

    Background The phylum Chlorophyta contains the majority of the green algae and is divided into four classes. While the basal position of the Prasinophyceae is well established, the divergence order of the Ulvophyceae, Trebouxiophyceae and Chlorophyceae (UTC) remains uncertain. The five complete chloroplast DNA (cpDNA) sequences currently available for representatives of these classes display considerable variability in overall structure, gene content, gene density, intron content and gene order. Among these genomes, that of the chlorophycean green alga Chlamydomonas reinhardtii has retained the least ancestral features. The two single-copy regions, which are separated from one another by the large inverted repeat (IR), have similar sizes, rather than unequal sizes, and differ radically in both gene contents and gene organizations relative to the single-copy regions of prasinophyte and ulvophyte cpDNAs. To gain insights into the various changes that underwent the chloroplast genome during the evolution of chlorophycean green algae, we have sequenced the cpDNA of Scenedesmus obliquus, a member of a distinct chlorophycean lineage. Results The 161,452 bp IR-containing genome of Scenedesmus features single-copy regions of similar sizes, encodes 96 genes, i.e. only two additional genes (infA and rpl12) relative to its Chlamydomonas homologue and contains seven group I and two group II introns. It is clearly more compact than the four UTC algal cpDNAs that have been examined so far, displays the lowest proportion of short repeats among these algae and shows a stronger bias in clustering of genes on the same DNA strand compared to Chlamydomonas cpDNA. Like the latter genome, Scenedesmus cpDNA displays only a few ancestral gene clusters. The two chlorophycean genomes share 11 gene clusters that are not found in previously sequenced trebouxiophyte and ulvophyte cpDNAs as well as a few genes that have an unusual structure; however, their single-copy regions differ

  1. Antitumor activity of Chlorella sorokiniana and Scenedesmus sp. microalgae native of Nuevo León State, México.

    Science.gov (United States)

    Reyna-Martinez, Raul; Gomez-Flores, Ricardo; López-Chuken, Ulrico; Quintanilla-Licea, Ramiro; Caballero-Hernandez, Diana; Rodríguez-Padilla, Cristina; Beltrán-Rocha, Julio Cesar; Tamez-Guerra, Patricia

    2018-01-01

    Cancer cases result in 13% of all deaths worldwide. Unwanted side effects in patients under conventional treatments have led to the search for beneficial alternative therapies. Microalgae synthesize compounds with known in vitro and in vivo biological activity against different tumor cell lines. Therefore, native microalgae from the State of Nuevo Leon, Mexico may become a potential source of antitumor agents. The aim of the present study was to evaluate the in vitro cytotoxic effect of Nuevo Leon regional Chlorella sorokiniana (Chlorellales: Chlorellaceae) and Scenedesmus sp. (Chlorococcales: Scenedesmaceae). Native microalgae crude organic extracts cytotoxicity against murine L5178Y-R lymphoma cell line and normal lymphocyte proliferation were evaluated using the MTT reduction colorimetric assay. Cell death pathway was analyzed by acridine orange and ethidium bromide staining, DNA degradation in 2% agarose gel electrophoresis and caspases activity. Results indicated significant ( p  < 0.05) 61.89% ± 3.26% and 74.77% ± 1.84% tumor cytotoxicity by C. sorokiniana and Scenedesmus sp. methanol extracts, respectively, at 500 µg/mL, by the mechanism of apoptosis. This study contributes to Mexican microalgae biodiversity knowledge and their potential as antitumor agent sources.

  2. Antitumor activity of Chlorella sorokiniana and Scenedesmus sp. microalgae native of Nuevo León State, México

    Science.gov (United States)

    Beltrán-Rocha, Julio Cesar

    2018-01-01

    Cancer cases result in 13% of all deaths worldwide. Unwanted side effects in patients under conventional treatments have led to the search for beneficial alternative therapies. Microalgae synthesize compounds with known in vitro and in vivo biological activity against different tumor cell lines. Therefore, native microalgae from the State of Nuevo Leon, Mexico may become a potential source of antitumor agents. The aim of the present study was to evaluate the in vitro cytotoxic effect of Nuevo Leon regional Chlorella sorokiniana (Chlorellales: Chlorellaceae) and Scenedesmus sp. (Chlorococcales: Scenedesmaceae). Native microalgae crude organic extracts cytotoxicity against murine L5178Y-R lymphoma cell line and normal lymphocyte proliferation were evaluated using the MTT reduction colorimetric assay. Cell death pathway was analyzed by acridine orange and ethidium bromide staining, DNA degradation in 2% agarose gel electrophoresis and caspases activity. Results indicated significant (p Scenedesmus sp. methanol extracts, respectively, at 500 µg/mL, by the mechanism of apoptosis. This study contributes to Mexican microalgae biodiversity knowledge and their potential as antitumor agent sources. PMID:29441241

  3. Antitumor activity of Chlorella sorokiniana and Scenedesmus sp. microalgae native of Nuevo León State, México

    Directory of Open Access Journals (Sweden)

    Raul Reyna-Martinez

    2018-02-01

    Full Text Available Cancer cases result in 13% of all deaths worldwide. Unwanted side effects in patients under conventional treatments have led to the search for beneficial alternative therapies. Microalgae synthesize compounds with known in vitro and in vivo biological activity against different tumor cell lines. Therefore, native microalgae from the State of Nuevo Leon, Mexico may become a potential source of antitumor agents. The aim of the present study was to evaluate the in vitro cytotoxic effect of Nuevo Leon regional Chlorella sorokiniana (Chlorellales: Chlorellaceae and Scenedesmus sp. (Chlorococcales: Scenedesmaceae. Native microalgae crude organic extracts cytotoxicity against murine L5178Y-R lymphoma cell line and normal lymphocyte proliferation were evaluated using the MTT reduction colorimetric assay. Cell death pathway was analyzed by acridine orange and ethidium bromide staining, DNA degradation in 2% agarose gel electrophoresis and caspases activity. Results indicated significant (p < 0.05 61.89% ± 3.26% and 74.77% ± 1.84% tumor cytotoxicity by C. sorokiniana and Scenedesmus sp. methanol extracts, respectively, at 500 µg/mL, by the mechanism of apoptosis. This study contributes to Mexican microalgae biodiversity knowledge and their potential as antitumor agent sources.

  4. The effect of colour light on production of zooids in 10 strains of the green chlorococcal alga Scenedesmus obliquus

    Czech Academy of Sciences Publication Activity Database

    Cepák, Vladislav; Přibyl, Pavel

    2006-01-01

    Roč. 6, - (2006), s. 127-133 ISSN 1213-3434 R&D Projects: GA ČR(CZ) GA204/03/1113 Institutional research plan: CEZ:AV0Z60050516 Keywords : colour light * Scenedesmus * life cycle Subject RIV: EF - Botanics

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    Chronic effects of the ionic liquid [C 4 mim][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 [C 4 mim][Cl], inhibition of both esterase activity and chlorophyll fluorescence became apparent after 3 days. Cell density was also decreased by culturing with [C 4 mim][Cl], but this effect was clearly concentration-dependent and only became significant during the second half of the experiment. In contrast, [C 4 mim][Cl] had only a modest effect on reactive oxygen species (ROS) and caused little damage to cell membranes. - Highlights: • Use of an advanced biological technique, flow cytometry, to elucidate ionic liquid toxicity. • Chronic effects of ionic liquid. • Membrane integrity and ROS studied. • Mechanism of ionic liquid toxicity. - [C 4 mim][Cl] significantly inhibited esterase activity, chlorophyll fluorescence and cell density, having only a modest effect on reactive oxygen species and cell membranes

  6. 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.

  7. 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

    2016-11-09

    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.

  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. The nucleocytosolic and chloroplast cycle in the green chlorococcal alga Scenedesmus obliquus (Chlorophyceae, Chlorococcales) grown under various temperatures

    Czech Academy of Sciences Publication Activity Database

    Cepák, Vladislav; Přibyl, Pavel; Vítová, Milada; Zachleder, Vilém

    2007-01-01

    Roč. 46, č. 3 (2007), s. 263-269 ISSN 0031-8884 R&D Projects: GA MŠk ME 575; GA ČR(CZ) GA204/03/1113; GA MŠk(CZ) 1M0571 Institutional research plan: CEZ:AV0Z60050516; CEZ:AV0Z50200510 Keywords : Scenedesmus * cell cycle * temperature Subject RIV: EF - Botanics Impact factor: 1.358, year: 2007

  10. Magnesium Aminoclay-Fe3O4 (MgAC-Fe3O4 Hybrid Composites for Harvesting of Mixed Microalgae

    Directory of Open Access Journals (Sweden)

    Bohwa Kim

    2018-05-01

    Full Text Available In this paper, we describe the synthesis of magnesium aminoclay-iron oxide (MgAC-Fe3O4 hybrid composites for microalgae-harvesting application. MgAC-templated Fe3O4 nanoparticles (NPs were synthesized in different ratios of MgAC and Fe3O4 NPs. The uniform distribution of Fe3O4 NPs in the MgAC matrix was confirmed by transmission electron microscopy (TEM. According to obtained X-ray diffraction (XRD patterns, increased MgAC loading leads to decreased intensity of the composites’ (311 plane of Fe3O4 NPs. For harvesting of Chlorella sp. KR-1, Scenedesmus obliquus and mixed microalgae (Chlorella sp. KR-1/ Scenedesmus obliquus, the optimal pH was 4.0. At higher pHs, the microalgae-harvesting efficiencies fell. Sample #1, which had the highest MgAC concentration, showed the most stability: the harvesting efficiencies for Chlorella sp. KR-1, Scenedesmus obliquus, and mixed microalgae were reduced only to ~50% at pH = 10.0. The electrostatic interaction between MgAC and the Fe3O4 NPs in the hybrid samples by microalgae, as confirmed by zeta potential measurements, were attributed to the harvesting mechanisms. Moreover, the zeta potentials of the MgAC-Fe3O4 hybrid composites were reduced as pH was increased, thus diminishing the microalgae-harvesting efficiencies.

  11. Biokinetics of cadmium, selenium, and zinc in freshwater alga Scenedesmus obliquus under different phosphorus and nitrogen conditions and metal transfer to Daphnia magna

    International Nuclear Information System (INIS)

    Yu Riqing; Wang Wenxiong

    2004-01-01

    The uptake of Cd, Se(IV) and Zn by the freshwater alga Scenedesmus obliquus and the subsequent transfer and release budget in Daphnia magna were investigated under different nutrient additions and cell incubation conditions. An increase in ambient phosphate concentrations from 0.5 μmol l -1 to 50 μmol l -1 significantly increased the intracellular accumulation of Cd (by 18x) and Zn (by 5x), but decreased the accumulation of Se (by 126x) in the alga. The percentage of these metals distributing in the intracellular pool of algae also increased substantially with increasing ambient P concentrations. Nitrate addition from 5.0 to 200 μmol l -1 did not influence the uptake of any of the three metals, although a significant decrease in the intracellular Se distribution was observed. Radiolabeled algae under different nutrient manipulations (semi-continuous culture, starvation, and P-pulse treatments) were used to measure trophic transfer assimilation efficiency (AE) in Daphnia. When the algal cells were grown in a semi-continuous culture, starved for N and P, or were treated with P-pulse, the AEs of Cd and Zn were generally independent of the nutritional conditions, but the Se AE was significantly affected by different P levels. The efflux rate constants, determined during 10 d depuration following 7 days of dietary uptake, decreased significantly for Cd and Zn, but were relatively constant for Se with increasing P concentration. N-addition caused no effect on the metal efflux rate constants. P- or N-additions did not influence the release budget (including molting, neonates, excretion and feces) for all three elements in Daphnia. Our study indicated that phosphate enrichment may substantially increase metal uptake in green alga S. obliquus. Responses of trophic transfer in Daphnia to nutrient enrichment were metal specific. P-enrichment can possibly lead to considerable decrease on Se transfer from algae to zooplankton. - Phosphorous enrichment influences metal uptake

  12. Biokinetics of cadmium, selenium, and zinc in freshwater alga Scenedesmus obliquus under different phosphorus and nitrogen conditions and metal transfer to Daphnia magna

    Energy Technology Data Exchange (ETDEWEB)

    Yu Riqing; Wang Wenxiong

    2004-06-01

    The uptake of Cd, Se(IV) and Zn by the freshwater alga Scenedesmus obliquus and the subsequent transfer and release budget in Daphnia magna were investigated under different nutrient additions and cell incubation conditions. An increase in ambient phosphate concentrations from 0.5 {mu}mol l{sup -1} to 50 {mu}mol l{sup -1} significantly increased the intracellular accumulation of Cd (by 18x) and Zn (by 5x), but decreased the accumulation of Se (by 126x) in the alga. The percentage of these metals distributing in the intracellular pool of algae also increased substantially with increasing ambient P concentrations. Nitrate addition from 5.0 to 200 {mu}mol l{sup -1} did not influence the uptake of any of the three metals, although a significant decrease in the intracellular Se distribution was observed. Radiolabeled algae under different nutrient manipulations (semi-continuous culture, starvation, and P-pulse treatments) were used to measure trophic transfer assimilation efficiency (AE) in Daphnia. When the algal cells were grown in a semi-continuous culture, starved for N and P, or were treated with P-pulse, the AEs of Cd and Zn were generally independent of the nutritional conditions, but the Se AE was significantly affected by different P levels. The efflux rate constants, determined during 10 d depuration following 7 days of dietary uptake, decreased significantly for Cd and Zn, but were relatively constant for Se with increasing P concentration. N-addition caused no effect on the metal efflux rate constants. P- or N-additions did not influence the release budget (including molting, neonates, excretion and feces) for all three elements in Daphnia. Our study indicated that phosphate enrichment may substantially increase metal uptake in green alga S. obliquus. Responses of trophic transfer in Daphnia to nutrient enrichment were metal specific. P-enrichment can possibly lead to considerable decrease on Se transfer from algae to zooplankton. - Phosphorous enrichment

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

    Directory of Open Access Journals (Sweden)

    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.

  14. Isolation and application of SOX and NOX resistant microalgae in biofixation of CO2 from thermoelectricity plants

    International Nuclear Information System (INIS)

    Radmann, Elisangela Martha; Vieira Camerini, Felipe; Duarte Santos, Thaisa; Vieira Costa, Jorge Alberto

    2011-01-01

    Highlights: → Microalgae can help reduce global warming. → Synechococcus nidulans and Chlorella vulgaris were isolated in a thermoelectric plant. → Microalgae were compared with Spirulina and Scenedesmus obliquus for CO 2 fixation. → Microalgae were exposed to CO 2 , SO 2 and NO, simulating a gas from coal combustion. → 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 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 2 biofixation. The microalgae were exposed to 12% CO 2 , 60 ppm of SO 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 2 biofixation of the coal combustion gas, which would help reduce global warming.

  15. 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., Zn 2+ 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 Zn 2+ 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 Zn 2+ have an ability to modulate the toxicity of GNPs in a real-world environment scenario.

  16. Uptake of uranium from sea water by microalgae

    International Nuclear Information System (INIS)

    Sakaguchi, Takashi; Horikoshi, Takao; Nakajima, Akira

    1978-01-01

    The uptake of uranium from aqueous systems especially from sea water by various microalgae was investigated. The freshwater microalgae, Chlorella regularis, Scenedesmus bijuga, Scenedesmus chloreloides, Scenedesmus obliquus, Chlamydomonas angulosa, Chlamydomonas reinhardtii, accumulated relatively large amounts of uranium from the solution containing uranium only. The concentration factors of the above mentioned algae were: Chlorella regularis 3930, Chlamydomonas 2330 - 3400, Scenedesmus 803 - 1920. The uptake of uranium from sea water by Chlorella regularis was inhibited markedly by the co-existence of carbonate ions. Chlorella cells could take up a great quantity of uranium from decarbonated sea water. The uptake of uranium was affected by the pH of sea water, and the amount of uranium absorbed was maximum at pH 5. The experiment was carried out to screen marine microalgae which have the ability to accumulate a large amount of uranium from sea water. The uptake of uranium from sea water by marine microalgae of different species turned out to be in the following decreasing order: Synechococcus > Chlamydomonas >> Chlorella > Dunaliella > Platymonas > Calothrix > Porphyridium. The amount of uranium absorbed differed markedly with different species of marine microalgae. (author)

  17. 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.

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

    International Nuclear Information System (INIS)

    Bhuvaneshwari, M.; Iswarya, V.; Archanaa, S.; Madhu, G.M.; Kumar, G.K. Suraish; Nagarajan, R.; Chandrasekaran, N.; Mukherjee, Amitava

    2015-01-01

    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 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 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

  19. Enhanced growth and fatty acid accumulation of microalgae Scenedesmus sp. LX1 by two types of auxin.

    Science.gov (United States)

    Dao, Guo-Hua; Wu, Guang-Xue; Wang, Xiao-Xiong; Zhuang, Lin-Lan; Zhang, Tian-Yuan; Hu, Hong-Ying

    2018-01-01

    Microalgae are potential candidates for the production of valuable products, such as renewable biodiesel, health products and pigments. However, low biomass productivity has restricted their large-scale applications. In this study, the effects of two auxins (one natural type of indole-3-acetic acid (IAA) and the other synthetic type of 2,4-dichlorophenoxyacetic acid (2,4-D)) on the growth and fatty acid methyl esters (FAMEs) production of a freshwater microalgae Scenedesmus sp. LX1 were investigated. Both auxins showed a "low dosage-promotion and high dosage-inhibition" effect on the growth and FAMEs accumulation. The optimum dosage of IAA and 2,4-D were 1mgL -1 and 0.1mgL -1 , respectively. Moreover, the IAA could increase the monounsaturated fatty acid content. The auxins may promote the growth by enhancing the photosynthetic activity through increasing chlorophyll contents. Therefore, auxin significantly enhanced microalgal growth and FAMEs accumulation, and has a potential for application in developing efficient microalgal cultivation. Copyright © 2017. Published by Elsevier Ltd.

  20. 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 CO 2 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. CO 2 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 CO 2 ranging from 5 to 25%, and the temperature and light intensities were kept constant. A maximum CO 2 fixation rate was observed at 15% CO 2 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 CO 2 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 CO 2 fixation was 0.12 ± 0.002 g/l/day at 15% CO 2 concentration. The carbohydrate and lipid content were maximum at 25% CO 2 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% CO 2 concentration.

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Improvement of stability and carotenoids fraction of virgin olive oils by addition of microalgae Scenedesmus almeriensis extracts.

    Science.gov (United States)

    Limón, Piedad; Malheiro, Ricardo; Casal, Susana; Acién-Fernández, F Gabriel; Fernández-Sevilla, José M; Rodrigues, Nuno; Cruz, Rebeca; Bermejo, Ruperto; Pereira, José Alberto

    2015-05-15

    Humans are not capable of synthesizing carotenoids de novo and thus, their presence in human tissues is entirely of dietary origin. Consumption of essential carotenoids is reduced due to the lower intake of fruits and vegetables. Microalgae are a good source of carotenoids that can be exploited. In the present work, carotenoids rich extracts from Scenedesmus almeriensis were added to extra-virgin olive oils at different concentrations (0.1 and 0.21 mg/mL) in order to enhance the consumption of these bioactives. Extracts brought changes in olive oils color, turning them orange-reddish. Quality of olive oils was improved, since peroxidation was inhibited. Olive oils fatty acids and tocopherols were not affected. β-carotene and lutein contents increase considerably, as well as oxidative stability, improving olive oils shelf-life and nutritional value. Inclusion of S. almeriensis extracts is a good strategy to improve and enhance the consumption of carotenoids, since olive oil consumption is increasing. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. 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)

    International Nuclear Information System (INIS)

    Rodríguez-Morales, Erik A.; Rodríguez de San Miguel, Eduardo; Gyves, Josefina de

    2015-01-01

    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. - Highlights: • The environmental bioavailability of copper(II) was determined using an HFSLM. • Two microalgae species were used as references for bioavailability evaluation. • Bioavailability is affected by the chemical conditions of the medium. • HFSLM and microalgae bioavailabilities depend on free copper(II) concentrations. • HFSLM emulates better the biological uptake of the Scenedesmus acutus microalga. - An HFSLM device may emulate the biological uptake of copper (II) of the Scenedesmus acutus microalga and, consequently, be used as a chemical test for bioavailability measurements.

  4. Cultivation and harvesting of microalgae in photobioreactor for biodiesel production and simultaneous nutrient removal

    International Nuclear Information System (INIS)

    Yang, Il-Seung; Salama, El-Sayed; Kim, Jong-Oh; Govindwar, Sanjay P.; Kurade, Mayur B.; Lee, Minsun; Roh, Hyun-Seog; Jeon, Byong-Hun

    2016-01-01

    Highlights: • Wastewater treatment with algal biomass production was evaluated in a bench-scale. • C. vulgaris and S. obliquus showed μ_o_p_t values of 1.39 and 1.41 day"−"1, respectively. • Complete removal (>99%) of TN and TP by both algal strains was observed. • Harvesting efficiency of M. oleifera was 81% for C. vulgaris and 92% for S. obliquus. - Abstract: Microalgae, Chlorella vulgaris and Scenedesmus obliquus were cultivated in a small scale vertical flat-plate photobioreactor (PBR) supplemented with municipal wastewater in order to achieve simultaneous wastewater treatment and biomass production for biofuel generation. Microalgal growth and nutrient removal including total nitrogen (TN), total phosphorus (TP), total inorganic carbon (TIC) and trace elements (Ca"2"+, Na"+, Mg"2"+ and Zn"2"+) were monitored during microalgae cultivation. C. vulgaris and S. obliquus showed optimal specific growth rates (μ_o_p_t) of 1.39 and 1.41 day"−"1, respectively, and the TN and TP were completely removed (>99%) from the wastewater within 8 days. Microalgal biomass in the PBR was harvested using a natural flocculant produced from Moringa oleifera seeds. The harvesting efficiency of M. oleifera was 81% for C. vulgaris and 92% for S. obliquus. The amounts of saturated, mono-unsaturated, and poly-unsaturated fatty acids in the harvested biomass accounted for 18.66%, 71.61% and 9.75% for C. vulgaris and 28.67%, 57.14% and 11.15% for S. obliquus, respectively. The accumulated fatty acids were suitable to produce high quality biodiesel with characteristics equivalent to crop seeds oil-derived biodiesel. This study demonstrates the potential of microalgae-based biodiesel production through the coupling of advanced wastewater treatment with microalgae cultivation for low-cost biomass production in a PBR.

  5. Effect of ultraviolet radiation on photosynthesis, biomass, and fatty acid content and profile of a Scenedesmus rubescens-like microalga.

    Science.gov (United States)

    Li, Ping; Lin, Junda

    2012-05-01

    The effects of ultraviolet radiation (UVR) and nitrogen (NaNO(3)) concentration on photosynthesis, biomass, and fatty acid content and profile of a Scenedesmus rubescens-like microalga were measured in an outdoor 8-day culture study. UV-induced photoinhibition decreased from 42.6% to 3.5%, in the presence of 75 mg/L NaNO(3) (HN) and from 52.9% to 22.6% in the presence of 7.5mg/L NaNO(3) (LN) nitrogen concentration, respectively. The concentrations of UV-absorbing compounds increased 4.3 and 4.9 times under HN and LN, respectively. Biomass accumulation was suppressed (10.7%) by UVR under HN, but not under LN conditions. Carotenoid content decreased from 1.05 ± 0.06 to 0.96 ± 0.15 (with UV radiation) and to 0.91 ± 0.07 (without UV radiation), respectively, under HN, while it decreased to 0.05 ± 0.04 (with UV radiation) and to 0.11 ± 0.08 (without UV radiation), respectively, under LN. The content of C18:1n9 fatty acids increased by about 430%, whereas that of C18:3n3 decreased by about 65% in both radiation treatments during nitrogen starvation. The results showed that the absence of UVR screening does not change the fatty acid content and profile of S. rubescens-like algae cultivated outdoors under HN and LN conditions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. 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.

  7. Microalgae as a raw material for biofuels production.

    Science.gov (United States)

    Gouveia, Luisa; Oliveira, Ana Cristina

    2009-02-01

    Biofuels demand is unquestionable in order to reduce gaseous emissions (fossil CO(2), nitrogen and sulfur oxides) and their purported greenhouse, climatic changes and global warming effects, to face the frequent oil supply crises, as a way to help non-fossil fuel producer countries to reduce energy dependence, contributing to security of supply, promoting environmental sustainability and meeting the EU target of at least of 10% biofuels in the transport sector by 2020. Biodiesel is usually produced from oleaginous crops, such as rapeseed, soybean, sunflower and palm. However, the use of microalgae can be a suitable alternative feedstock for next generation biofuels because certain species contain high amounts of oil, which could be extracted, processed and refined into transportation fuels, using currently available technology; they have fast growth rate, permit the use of non-arable land and non-potable water, use far less water and do not displace food crops cultures; their production is not seasonal and they can be harvested daily. The screening of microalgae (Chlorella vulgaris, Spirulina maxima, Nannochloropsis sp., Neochloris oleabundans, Scenedesmus obliquus and Dunaliella tertiolecta) was done in order to choose the best one(s), in terms of quantity and quality as oil source for biofuel production. Neochloris oleabundans (fresh water microalga) and Nannochloropsis sp. (marine microalga) proved to be suitable as raw materials for biofuel production, due to their high oil content (29.0 and 28.7%, respectively). Both microalgae, when grown under nitrogen shortage, show a great increase (approximately 50%) in oil quantity. If the purpose is to produce biodiesel only from one species, Scenedesmus obliquus presents the most adequate fatty acid profile, namely in terms of linolenic and other polyunsaturated fatty acids. However, the microalgae Neochloris oleabundans, Nannochloropsis sp. and Dunaliella tertiolecta can also be used if associated with other

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Isolation and selection of microalgae from coal fired thermoelectric power plant for biofixation of carbon dioxide

    International Nuclear Information System (INIS)

    Morais, Michele Greque de; Costa, Jorge Alberto Vieira

    2007-01-01

    Global warming is thought to be caused mainly by the emission of carbon dioxide (CO 2 ), with thermoelectric power plants being responsible for about 7% of global CO 2 emissions. Microalgae can reduce CO 2 emissions from thermoelectric power plants, but for this use, they must be resistant to the mixture of gases produced by the power plants. We isolated the microalgae Scenedesmus obliquus and Chlorella kessleri from the waste treatment ponds of the Presidente Medici coal fired thermoelectric power plant in the Southernmost Brazilian state of Rio Grande do Sul and investigated their growth characteristics when exposed to different concentrations of CO 2 . When cultivated with 6% and 12% CO 2 , C. kessleri showed a high maximum specific growth rate (μ max ) of 0.267/day, with a maximum biomass productivity (P max ) of 0.087 g/L/day at 6% CO 2 . For S. obliquus, the highest maximum dry weight biomass value was 1.14 g/L with 12% CO 2 . We also found that these two microalgae also grew well when the culture medium contained up to 18% CO 2 , indicating that they have potential for biofixation of CO 2 in thermoelectric power plants

  19. Isolation and selection of microalgae from coal fired thermoelectric power plant for biofixation of carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    de Morais, M.G.; Costa, J.A.V. [Federal University of Rio Grande, Rio Grande (Brazil)

    2007-07-15

    Global warming is thought to be caused mainly by the emission of carbon dioxide (CO{sub 2}), with thermoelectric power plants being responsible for about 7% of global CO{sub 2} emissions. Microalgae can reduce CO{sub 2} emissions from thermoelectric power plants, but for this use, they must be resistant to the mixture of gases produced by the power plants. We isolated the microalgae Scenedesmus obliquus and Chlorella kessleri from the waste treatment ponds of the Presidente Medici coal fired thermoelectric power plant in the Southernmost Brazilian state of Rio Grande do Sul and investigated their growth characteristics when exposed to different concentrations of CO{sub 2}. When cultivated with 6% and 12% CO{sub 2}, C. kessleri showed a high maximum specific growth rate ({lambda}{sub max}) of 0.267/day, with a maximum biomass productivity (P-max) of 0.087 g/L/day at 6% CO{sub 2}. For S. obliquus, the highest maximum dry weight biomass value was 1.14 g/L with 12% CO{sub 2}. We also found that these two microalgae also grew well when the culture medium contained up to 18% CO{sub 2}, indicating that they have potential for biofixation of CO{sub 2} in thermoelectric power plants.

  20. Isolation and selection of microalgae from coal fired thermoelectric power plant for biofixation of carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Michele Greque de [Department of Chemistry, Laboratory of Biochemistry Engineering, Federal University Foundation of Rio Grande, Rio Grande, RS (Brazil); Costa, Jorge Alberto Vieira [Department of Chemistry, Laboratory of Biochemistry Engineering, Federal University Foundation of Rio Grande, Rio Grande, RS (Brazil)]. E-mail: dqmjorge@furg.br

    2007-07-15

    Global warming is thought to be caused mainly by the emission of carbon dioxide (CO{sub 2}), with thermoelectric power plants being responsible for about 7% of global CO{sub 2} emissions. Microalgae can reduce CO{sub 2} emissions from thermoelectric power plants, but for this use, they must be resistant to the mixture of gases produced by the power plants. We isolated the microalgae Scenedesmus obliquus and Chlorella kessleri from the waste treatment ponds of the Presidente Medici coal fired thermoelectric power plant in the Southernmost Brazilian state of Rio Grande do Sul and investigated their growth characteristics when exposed to different concentrations of CO{sub 2}. When cultivated with 6% and 12% CO{sub 2}, C. kessleri showed a high maximum specific growth rate ({mu} {sub max}) of 0.267/day, with a maximum biomass productivity (P {sub max}) of 0.087 g/L/day at 6% CO{sub 2}. For S. obliquus, the highest maximum dry weight biomass value was 1.14 g/L with 12% CO{sub 2}. We also found that these two microalgae also grew well when the culture medium contained up to 18% CO{sub 2}, indicating that they have potential for biofixation of CO{sub 2} in thermoelectric power plants.

  1. 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.

  2. 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.

  3. Ratio between autoflocculating and target microalgae affects the energy-efficient harvesting by bio-flocculation

    NARCIS (Netherlands)

    Salim, S.; Vermuë, M.H.; Wijffels, R.H.

    2012-01-01

    The effect of ratio between autoflocculating and target microalgae in bio-flocculation was studied with emphasis on the recovery, sedimentation rate and energy demand for harvesting the target microalgae. When the autoflocculating microalgae Ettlia texensis, Ankistrodesmus falcatus and Scenedesmus

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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,

  9. 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.)

  10. Using Scenedesmus sp. for the Phycoremediation of Tannery Wastewater

    OpenAIRE

    Ballén-Segura, Miguel; Hernández Rodríguez, Luisa; Parra Ospina, David; Vega Bolaños, Asly; Pérez, Karen

    2016-01-01

    Wastewater from the leather tannery industry contains high concentrations of heavy metals, especially chromium, as well as high values of inorganic nutrients and organic matter which, if not treated prior to discharge, may alter the quality of surface water bodies. As an alternative treatment to these industrial effluents, we propose the use of microalgae, due to their ability to remove contaminants. This study evaluates the growth of the microalga Scenedesmus sp. in three different dilutions...

  11. 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

  12. 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

    2016-01-01

    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. PMID:26932369

  13. Hydrothermal Disintegration and Extraction of Different Microalgae Species

    Directory of Open Access Journals (Sweden)

    Michael Kröger

    2018-02-01

    Full Text Available For the disintegration and extraction of microalgae to produce lipids and biofuels, a novel processing technology was investigated. The utilization of a hydrothermal treatment was tested on four different microalgae species (Scenedesmus rubescens, Chlorella vulgaris, Nannochloropsis oculata and Arthorspira platensis (Spirulina to determine whether it has an advantage in comparison to other disintegration methods for lipid extraction. It was shown, that hydrothermal treatment is a reasonable opportunity to utilize microalgae without drying and increase the lipid yield of an algae extraction process. For three of the four microalgae species, the extraction yield with a prior hydrothermal treatment elevated the lipid yield up to six times in comparison to direct extraction. Only Scenedesmus rubescens showed a different behaviour. Reason can be found in the different cell wall of the species. The investigation of the differences in cell wall composition of the used species indicate that the existence of algaenan as a cell wall compound plays a major role in stability.

  14. 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 NH 4 + -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.

  15. 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.

  16. Microalgae respond differently to nitrogen availability during culturing

    Indian Academy of Sciences (India)

    Variations in the exogenous nitrogen level are known to significantly affect the physiological status and metabolism of microalgae. However, responses of red, green and yellow-green algae to nitrogen (N) availability have not been compared yet. Porphyridium cruentum, Scenedesmus incrassatulus and Trachydiscus ...

  17. 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.

  18. 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.

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

    Directory of Open Access Journals (Sweden)

    Rakesh Singh Gour

    Full Text Available 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. 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.

  1. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  3. Optimization of the digestion process of Scenedesmus sp. and Opuntia maxima for biogas production

    International Nuclear Information System (INIS)

    Ramos-Suárez, Juan Luis; Martínez, Alejandro; Carreras, Nely

    2014-01-01

    Highlights: • Scenedesmus biomass showed low biodegradability and biogas production. • Methane yield and kinetics of the batch process were improved by co-digestion. • Scenedesmus and Opuntia maxima were successfully co-digested in CSTR. • High biogas yields were obtained and no inhibition by ammonia was observed. - Abstract: Scenedesmus biomass is not an adequate substrate for anaerobic digestion due to its low biodegradability and low biogas yield. This study aims to evaluate the anaerobic co-digestion of Scenedesmus microalgal biomass and Opuntia maxima cladodes, the latter added in order to improve the digestion process. Batch assays were conducted to evaluate possible synergistic effects in different mixtures of both substrates. Mixture with highest methane yield was digested in semi-continuous mode at different VS concentrations. Feedstock composed of 75% O.maxima and 25% Scenedesmus (VS basis) showed the highest methane yield increasing 66.4% and 63.9% that of Scenedesmus and O.maxima, respectively. In semi-continuous mode, ideal organic loading rate (OLR) with 6%VS feed concentration was 4 gVS L −1 d −1 , which yielded 292 ± 39 L CH4 kgVS −1 (15 days HRT). In the case of 8%VS feed concentration ideal OLR was 5.33 gVS L −1 d −1 , which yielded 308 ± 22 L CH4 kgVS −1 (15 days HRT). The co-digestion of O.maxima and Scenedesmus biomass enhanced the anaerobic digestion process and avoided inhibition caused by low C/N ratio of microalgae

  4. Growth performance and biochemical composition of nineteen microalgae collected from different Moroccan reservoirs

    Directory of Open Access Journals (Sweden)

    EL. A. IDRISSI ABDELKHALEK

    2016-03-01

    Full Text Available Macro- and microalgae have recently received much attention due to their valuable chemical constituents. In order to increase existing data, the authors studied nineteen microalgae species isolated from different reservoirs in the Fez region (northern Morocco, undertaking experiments to determine for each species the specific growth rate, their total amounts of proteins, carbohydrates and lipids and the influence of the growth phase on these chemical constituents. Conditions of cultivation were as follows: light intensity equal to 300 μmol photons m-2 s-1, with a temperature regime of 25/20°C (day/night and a 16/8 (light/dark photoperiod cycle. The growth rates of the nineteen studied species of microalgae showed a wide variation between species, ranging from 0.27 g l-1 d-1 for Chlamydomonas ovalis to 3.64 g l-1 d-1 for Chlorococcum wemmeri. Protein, carbohydrate and lipid contents varied greatly between taxa and within genera. Ankistrodesmus falcatus, Chlamydomonas ovalis, Chlorococcum sp., Hyaloraphidium contortum, Scenedesmus protuberans, and Synechocystis aquatilis tended to synthesize proteins, the concentrations exceeding 20% dry weight (DW. Ankistrodesmus falcatus, Ankistrodesmus sp., Chlorococcum wemmeri, Coenocystis sp., Isocystis sp., Lyngbya bergei, Oscillatoria amphibia, Polytoma papillatum, Scenedesmus protuberans, Scenedesmus sp. and Synechocystis aquatilis showed a high capacity for lipid storage, greater than 20% DW. For carbohydrate contents, only Scenedesmus protuberans and Scenedesmus quadricauda showed an excessive level compared to other scanned species with 29.21% and 24.76% DW, respectively.

  5. 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.

  6. The Potential of Microalgae Lipids for Edible Oil Production.

    Science.gov (United States)

    Huang, Yanfei; Zhang, Dongmei; Xue, Shengzhang; Wang, Meng; Cong, Wei

    2016-10-01

    The objective of this study was to evaluate the potential of oil-rich green algae, Chlorella vulgaris, Scenedesmus obliquus, and Nannochloropsis oceanica, to produce edible oil with respect to lipid and residue properties. The results showed that C. vulgaris and N. oceanica had similarly much higher lipid recovery (about 50 %) in hexane extraction than that of S. obliquus (about 25 %), and C. vulgaris had the highest content of neutral lipids among the three algae. The fatty acid compositions of neutral lipids from C. vulgaris and S. obliquus were mainly C16 and C18, resembling that of vegetable oils. ARA and EPA were the specific valuable fatty acids in lipids of N. oceanica, but the content of which was lower in neutral lipids. Phytol was identified as the major unsaponifiable component in lipids of the three algae. Combined with the evaluation of the ratios in SFA/MUFA/PUFA, (n-6):(n-3) and content of free fatty acids, lipids obtained from C. vulgaris displayed the great potential for edible oil production. Lipids of N. oceanica showed the highest antioxidant activity, and its residue contained the largest amounts of protein as well as the amino acid compositions were greatly beneficial to the health of human beings.

  7. 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.

  8. 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 ...

  9. 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.

  10. Fatty Acid Content of Indonesian Aquatic Microalgae

    Directory of Open Access Journals (Sweden)

    TRI PRARTONO

    2010-12-01

    Full Text Available High utilization of fossil fuel increases the level of carbon dioxide in the atmosphere and results in global warming phenomenon. These things establish the world's thought to look for the other alternative energy that can reduce the use of fossil fuel even to be replaced by the substitute. Recently, Indonesia has been doing the research of microalgae as a feedstock of an alternative biofuel. Fatty acid content that microalgae have is also high to produce biofuel. The steps used in this research is a 7 days cultivation, harvesting, extraction using hexane, and fatty acid identification using Gas Chromatography of microalgae species. Fatty acid component in some species such as Chlorella sp., Scenedesmus sp., Nannochloropsis sp., and Isochrysis sp. is between 0.21-29.5%; 0.11-25.16%; 0.30-42.32%; 2.06-37.63%, respectively, based on dry weight calculation. The high content of fatty acid in some species of microalgae showed the potential to be the feedstock of producing biofuel in overcoming the limited utilization from petroleum (fossil fuel presently.

  11. Outdoor Growth Characterization of an Unknown Microalga Screened from Contaminated Chlorella Culture

    Directory of Open Access Journals (Sweden)

    Shuhao Huo

    2017-01-01

    Full Text Available Outdoor microalgae cultivation process is threatened by many issues, such as pest pollution and complex, changeable weather. Therefore, it is difficult to have identical growth rate for the microalgae cells and to keep their continuous growth. Outdoor cultivation requires the algae strains not only to have a strong ability to accumulate oil, but also to adapt to the complicated external environment. Using 18S rRNA technology, one wild strain Scenedesmus sp. FS was isolated and identified from the culture of Chlorella zofingiensis. Upon contamination by Scenedesmus sp., the species could quickly replace Chlorella zofingiensis G1 and occupy ecological niche in the outdoor column photobioreactors. The results indicated that Scenedesmus sp. FS showed high alkali resistance. It also showed that even under the condition of a low inoculum rate (OD680, 0.08, Scenedesmus sp. FS could still grow in the outdoor raceway pond under a high alkaline environment. Even under unoptimized conditions, the oil content of Scenedesmus sp. FS could reach more than 22% and C16–C18 content could reach up to 79.68%, showing that this species has the potential for the biodiesel production in the near future.

  12. Microalgae Nutraceuticals

    Directory of Open Access Journals (Sweden)

    Marcello Nicoletti

    2016-08-01

    Full Text Available Among the new entries in the food supplements sector, an important place must be assigned to nutraceuticals containing microalgae, nowadays accounting for a large and rapidly expanding market. The marketed products are mainly based on three production strains, i.e., Spirulina and Chlorella, followed at a distance by Klamath. It is a composite situation, since two of them are cyanobacteria and the second one is eukaryotic. The reality is that each presents similarities in shape and appearance concerning the marketed form and several utilizations, and peculiarities that need special attention and adequate studies. First, general information is reported about the current scientific knowledge on each microalga, in particular the nutritional value and properties in prevention and wellbeing. Second, original studies are presented concerning the quality control of marketed products. Quality control is a key argument in nutraceuticals validation. Microalgae are particular organisms that need specific approaches to confirm identity and validate properties. The proposed control of quality is based on microscopic analysis of the morphologic characteristics. The final parts of this paper are dedicated to the need for specificity in uses and claims and to considerations about the future of microalgae in food supplements.

  13. 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...

  14. 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.

  15. Isolation and Characterization of Native Microalgae from the Peruvian Amazon with Potential for Biodiesel Production

    Directory of Open Access Journals (Sweden)

    Marianela Cobos

    2017-02-01

    Full Text Available Biodiesel production from microalgae triacylglycerols is growing, because this feedstock is a more sustainable and advantageous alternative. In this study, we isolated and identified fourteen strains of native microalgae from the Peruvian Amazon. These strains showed great heterogeneity in biomass productivity, lipid productivity and lipid content, and thus, three of them (Acutodesmus obliquus, Ankistrodesmus sp. and Chlorella lewinii were selected for further evaluation under culture of nitrogen-sufficient (+N and nitrogen-deficient (−N Chu medium No. 10. These microalgae species showed modifications in biomolecule content (protein, lipid and carbohydrate with a pronounced increase of lipids and carbohydrate and a decrease of protein content under stress culture. Furthermore, the fatty acid profile was peculiar for each species, and these patterns showed evident changes, particularly in the proportion of saturated and monounsaturated fatty acids. The results of this research suggest that the isolated native microalgae, from the Peruvian Amazon, could be suitable candidates for biodiesel production

  16. Oxyfluorfen toxic effect on S. obliquus evaluated by different photosynthetic and enzymatic biomarkers.

    Science.gov (United States)

    Geoffroy, L; Dewez, D; Vernet, G; Popovic, R

    2003-11-01

    The effect of oxyfluorfen was investigated when alga Scenedesmus obliquus has been exposed to different concentrations (7.5, 15, and 22.5 microg x L(-1)) at 12, 24, and 48 hours of exposure. Toxicity test was done by using 13 biomarkers concerning growth rate, chlorophyll content and indicators of photosynthetic and antioxidant enzyme activities. The change of the 13 parameters showed a great variation of sensitivity indicating differences in parameters' suitability to be used as biomarkers when alga culture was exposed to oxyfluorfen toxicity. The order of sensitivity between those biomarkers was: Antenna size (ABS/RC) > Chlorophyll content > Catalase (CAT) > Operational PSII quantum yield (phiS(PSII)) > Glutathione S-transferase (GST) > Functional plastoquinone pool (Q(PQ)) > Glutathione reductase (GR) > Growth rate > Nonphotochemical quenching (QN) > Proton gradient quenching (Q(Emax)) > Ascorbate peroxidase (APX) > Photochemical quenching (Q(p)) > Maximum PSII quantum yield (Phi(PSII)). The effect of oxyfluorfen on the changes of those parameters was interpreted as a result of herbicide mode of action at molecular level of alga cellular system. This study indicated for some photosynthetic and enzymatic biomarkers to be useful indicators of toxicity effect induced in non-target alga species. Determination of biomarkers' sensitivity order may facilitate their selection to be used in environmental risk assessment of polluted water.

  17. 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.

  18. Microalgae community shifts during the biogas upgrading in an alkaline open photobioreactor.

    Science.gov (United States)

    Granada-Moreno, C I; Aburto-Medina, A; de Los Cobos Vasconcelos, D; González-Sánchez, A

    2017-10-01

    To achieve the functional specialization of a microalgae community through operational tuning of an open photobioreactor used for biogas upgrading under alkaline conditions. An open photobioreactor was inoculated with an indigenous microalgae sample from the Texcoco Soda Lake. A microalgae community was adapted to fix CO 2 from synthetic biogas through different culture conditions reaching a maximum of 220 mg CO 2  l -1 per day. Picochlorum sp. and Scenedesmus sp. were identified as the prominent microalgae genera by molecular fingerprinting (partial sequencing of 16S rRNA and 18S rRNA genes) but only the first was detected by microscopy screening. Changes in the microalgae community profile were monitored by a range-weighted richness index, reaching the lowest value when biogas was upgraded. A robust microalgae community in the open photobioreactor was obtained after different culture conditions. The specialization of microalgae community for CO 2 fixation under H 2 S presence was driven by biogas upgrading conditions. The alkaline conditions enhance the CO 2 absorption from biogas and could optimize specialized microalgae communities in the open photobioreactor. Denaturing gradient gel electrophoresis fingerprinting and richness index comparison are useful methods for the evaluation of microalgae community shifts and photosynthetic activity performance, particularly in systems intended for CO 2 removal from biogas where the CO 2 assimilation potential can be related to the microbial richness. © 2017 The Society for Applied Microbiology.

  19. Synergistic effect of pretreatment and fermentation process on carbohydrate-rich Scenedesmus dimorphus for bioethanol production

    International Nuclear Information System (INIS)

    Chng, Lee Muei; Lee, Keat Teong; Chan, Derek Juinn Chieh

    2017-01-01

    Highlights: • Biomass of Scenedesmus dimorphus is degradable to produce fermentable sugar. • Sugar yield improves with acidic, enzymatic and organosolv pretreatment. • Pretreatment strategies are positively correlated with fermentation process. • SSF with organosolv-treated biomass is promising for bioethanol production. - Abstract: Significant development in conversion technologies to produce bioethanol from microalgae biomass is causing paradigm-shift in energy management. In this study, carbohydrate-rich microalgae, Scenedesmus dimorphus (49% w/w of carbohydrate) is selected with the aim to obtain qualitative correlation between pretreatment and fermentation process. In view of this, separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) were conducted experimentally. The fermentation behavior were investigated for microalgae biomass treated via organosolv, enzymatic and acidic pretreatment. Fermentation process was carried out by ethanologen microbe, Saccharomyces cerevisiae. From the result, it is observed that a combination of two treatment is found to be the most effective in producing fermentable sugar for the subsequent fermentation process. The organosolv treatment which is followed with the SSF process produced a theoretical yield of bioethanol that exceeded 90%. On the other hand, hydrothermal acid-hydrolyzed fermentation produced the bioethanol yield with 80% of its theoretical yield. Enzymatic-hydrolyzed SHF produced 84% of theoretical yield at longer reaction time compared with others. The results were obtained with constant fermentation parameters conducted at pH 5, temperature of 34 °C, and microalgae biomass loading at 18 g/L. Ultimately, the coupling of organosolv-treated biomass with SSF process is found to be the most cost-effective for S. dimorphus biomass as bioethanol feedstock.

  20. Lipid production from tapioca wastewater by culture of Scenedesmus sp. with simultaneous BOD, COD and nitrogen removal

    Science.gov (United States)

    Romaidi; Hasanudin, Muhammad; Kholifah, Khusnul; Maulidiyah, Alik; Putro, Sapto P.; Kikuchi, Akira; Sakaguchi, Toshifumi

    2018-05-01

    The use of microalgae to produce biodiesel or possibly remove nutrients from industrial wastewater has gained important attention during recent years due to their photosynthetic rate and its versatile nature to grow in various wastewater systems. In this study, a microalgae, Scenedesmus sp., was cultured to enhance the lipid production and nutrients removal from tapioca wastewater sample. To assess lipid production, Scenedesmus sp. was cultured in different concentration of tapioca wastewater sample (from 0 to 100 %), and nutrient removal including BOD, COD, NH4, NO2, NO3 level by Scenedesmus sp. was assessed in 100% of tapioca wastewater culture. After 8 days of culture, it was found out that 50% of tapioca wastewater sample resulted in highest concentration of lipid content than that of the other concentrations. The level of environment indicator as nutrient removal such as BOD, COD, NH4, NO2, NO3 were also decreased up to 74%, 72%, 95%, 91%, and 91%, respectively. The pH condition changed from initial condition acidic (pH: 4) to neutral or basic condition (pH: 7-8) as recommended in wastewater treatment system. This research provided a novel approach and achieved efficient simultaneous lipid production and nutrients removal from tapioca wastewater sample by Scenedesmus’s culture system.

  1. Bioprocesses for removal of carbon dioxide and nitrogen oxide by microalgae for the utilization of gas generated during coal burning

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Michele Greque de; Costa, Jorge Alberto Vieira [Fundacao Universidade Federal do Rio Grande, Rio Grande (Brazil)

    2008-07-01

    The aim of this work was to study the removal of CO{sub 2} and NO by microalgae and to evaluate the kinetic characteristics of the cultures. Spirulina sp. showed {mu}{sub max} and X{sub max} (0.11 d{sup -1}, 1.11 g L{sup -1} d{sup -1}) when treated with CO{sub 2} and NaNO{sub 3}. The maximum CO{sub 2} removal was 22.97% for S. obliquus treated with KNO{sub 3} and atmospheric CO{sub 2}. The S. obliquus showed maximum NO removal (21.30%) when treated with NO and CO{sub 2}. Coupling the cultivation of these microalgae with the removal of CO{sub 2} and NO has the potential not only to reduce the costs of culture media but also to offset carbon and nitrogen emissions. 19 refs., 3 figs., 2 tabs.

  2. Influence of pathogenic bacterial activity on growth of Scenedesmus sp. and removal of nutrients from public market wastewater.

    Science.gov (United States)

    Al-Gheethi, A A; Mohamed, R M; Jais, N M; Efaq, A N; Abd Halid, Abdullah; Wurochekke, A A; Amir-Hashim, M K

    2017-10-01

    The present study aims to investigate the influence of Staphylococcus aureus, Escherichia coli and Enterococcus faecalis in public market wastewater on the removal of nutrients in terms of ammonium (NH 4 - ) and orthophosphate (PO 4 3 ) using Scenedesmus sp. The removal rates of NH 4 - and orthophosphate PO 4 3- and batch kinetic coefficient of Scenedesmus sp. were investigated. The phycoremediation process was carried out at ambient temperature for 6 days. The results revealed that the pathogenic bacteria exhibited survival potential in the presence of microalgae but they were reduced by 3-4 log at the end of the treatment process. The specific removal rates of NH 4 - and PO 4 3- have a strong relationship with initial concentration in the public market wastewater (R 2 = 0.86 and 0.80, respectively). The kinetic coefficient of NH 4 - removal by Scenedesmus sp. was determined as k = 4.28 mg NH 4 - 1 log 10 cell mL -1 d -1 and k m = 52.01 mg L -1 (R 2 = 0.94) while the coefficient of PO 4 3- removal was noted as k = 1.09 mg NH 4 - 1 log 10 cell mL -1 d -1 and k m = 85.56 mg L -1 (R 2 = 0.92). It can be concluded that Scenedesmus sp. has high competition from indigenous bacteria in the public market wastewater to remove nutrients, with a higher coefficient of removal of NH 4 - than PO 4 3 .

  3. 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.

  4. 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.

  5. A Saponification Method for Chlorophyll Removal from Microalgae Biomass as Oil Feedstock

    Directory of Open Access Journals (Sweden)

    Tao Li

    2016-09-01

    Full Text Available Microalgae oil is an optimal feedstock for nutraceutical, pharmaceutical and biodiesel production, but its high levels of chlorophyll limit its large-scale application. To date, few effective approaches have been developed to remove chlorophyll from microalgae oil. The main purpose of this study was to present a preprocessing method of algae oil feedstock (Scenedesmus to remove chlorophyll by saponification. The results showed that 96% of chlorophyll in biomass was removed. High quality orange transparent oil could be extracted from the chlorophyll reduced biomass. Specifically, the proportion of neutral lipids and saturation levels of fatty acids increased, and the pigments composition became carotenoids-based. The critical parameters of chlorophyll reduced biodiesel conformed to the standards of the USA, China and EU. Sodium copper chlorophyllin could be prepared from the bleaching effluent. The results presented herein offer a useful pathway to improve the quality of microalgae oil and reduce the cost of microalgae biodiesel.

  6. A Saponification Method for Chlorophyll Removal from Microalgae Biomass as Oil Feedstock

    Science.gov (United States)

    Li, Tao; Xu, Jin; Wu, Hualian; Wang, Guanghua; Dai, Shikun; Fan, Jiewei; He, Hui; Xiang, Wenzhou

    2016-01-01

    Microalgae oil is an optimal feedstock for nutraceutical, pharmaceutical and biodiesel production, but its high levels of chlorophyll limit its large-scale application. To date, few effective approaches have been developed to remove chlorophyll from microalgae oil. The main purpose of this study was to present a preprocessing method of algae oil feedstock (Scenedesmus) to remove chlorophyll by saponification. The results showed that 96% of chlorophyll in biomass was removed. High quality orange transparent oil could be extracted from the chlorophyll reduced biomass. Specifically, the proportion of neutral lipids and saturation levels of fatty acids increased, and the pigments composition became carotenoids-based. The critical parameters of chlorophyll reduced biodiesel conformed to the standards of the USA, China and EU. Sodium copper chlorophyllin could be prepared from the bleaching effluent. The results presented herein offer a useful pathway to improve the quality of microalgae oil and reduce the cost of microalgae biodiesel. PMID:27618070

  7. A Saponification Method for Chlorophyll Removal from Microalgae Biomass as Oil Feedstock.

    Science.gov (United States)

    Li, Tao; Xu, Jin; Wu, Hualian; Wang, Guanghua; Dai, Shikun; Fan, Jiewei; He, Hui; Xiang, Wenzhou

    2016-09-07

    Microalgae oil is an optimal feedstock for nutraceutical, pharmaceutical and biodiesel production, but its high levels of chlorophyll limit its large-scale application. To date, few effective approaches have been developed to remove chlorophyll from microalgae oil. The main purpose of this study was to present a preprocessing method of algae oil feedstock (Scenedesmus) to remove chlorophyll by saponification. The results showed that 96% of chlorophyll in biomass was removed. High quality orange transparent oil could be extracted from the chlorophyll reduced biomass. Specifically, the proportion of neutral lipids and saturation levels of fatty acids increased, and the pigments composition became carotenoids-based. The critical parameters of chlorophyll reduced biodiesel conformed to the standards of the USA, China and EU. Sodium copper chlorophyllin could be prepared from the bleaching effluent. The results presented herein offer a useful pathway to improve the quality of microalgae oil and reduce the cost of microalgae biodiesel.

  8. 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.

  9. Enhancement of total lipid yield by nitrogen, carbon, and iron supplementation in isolated microalgae.

    Science.gov (United States)

    Sivaramakrishnan, Ramachandran; Incharoensakdi, Aran

    2017-08-01

    The biochemical contents and biodiesel production ability of three microalgal strains grown under different sodium nitrate, sodium carbonate, and ferric ammonium citrate (iron) levels were investigated. The highest biomass and lipid contents were found in Scenedesmus sp., Chlorella sp., and Chlamydomonas sp. when grown in normal BG-11 containing sodium carbonate concentration at 0.03 g · L -1 , and in normal BG-11 containing iron concentration (IC) at 0.009 or 0.012 g · L -1 . Increasing the sodium nitrate level increased the biomass content, but decreased the lipid content in all three microalgae. Among the three microalgae, Scenedesmus sp. showed the highest total lipid yield of 0.69 g · L -1 under the IC of 0.012 g · L -1 . Palmitic and oleic acids were the major fatty acids of Scenedesmus sp. and Chlamydomonas sp. lipids. On the other hand, Chlorella sp. lipids were rich in palmitic, oleic, and linolenic acids, and henceforth contributing to poor biodiesel properties below the standard limits. The three isolated strains had a potential for biodiesel production. Nevertheless, Scenedesmus sp. from stone quarry pond water was the most suitable source for biodiesel production with tolerance toward the high concentration of sodium carbonate without the loss of its biodiesel properties. © 2017 Phycological Society of America.

  10. Diseño de pan con masa madre y microalgas

    OpenAIRE

    Lara Martínez, Irene Fernán

    2015-01-01

    [EN] Bread is a food with high consumption in the Spanish population. Demand of different varieties of it is increasing, moreover it has to provide extra health nutritional benefits. For this reason this paper aims to the formulation, preparation and subsequent rating of 4 breads made from 4 sourdough which were incorporated 1.5% of 4 different species of microalgae to each of them: Isochrysis galbana, Tetraselmis suecica, Scenedesmus almeriensis and Nannochloropsis gaditana. ...

  11. 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.

  12. 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.

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

    Science.gov (United States)

    Reshma, Ragini; Arumugam, Muthu

    2017-10-01

    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.

  14. Green energy from microalgae: Usage of algae biomass for anaerobic digestion

    International Nuclear Information System (INIS)

    Skorupskaite, Virginija; Makarevicie, Violeta

    2014-01-01

    The microalgae biomass can be used for various types of biofuels, including biodiesel and biogas. The aim of this study is to investigate the possibilities of microalgae Scenedesmus sp. and Chlorella sp. (widespread in freshwater Lithuanian lakes) usage for biogas production. Microalgae were cultivated under mixotrophic conditions (growth medium BG11 containing technical glycerol). In order to determine biogas yield and quality dependence on feedstock preparation, the analyses of biogas production have been performed with algae biomass prepared i n different ways: wet centrifuged; wet centrifuged, frozen and defrost; dry not de-oiled and dry de-oiled. The highest biogas yield in both cases (Scenedesmus sp. – 646 ml/gDM and Chlorella sp. – 652 ml/gDM) was obtained from centrifuged, frozen and defrost biomass. Biogas yield was app. 1.46 times higher comparing to yield of biogas produced from wastewater sludge. Our results showed that different types of biomass preparation have no significant influence on quality of biogas. Key words: microalgae, biomass, biogas production, biogas quality

  15. 60 Co accumulation by scenedesnus obliquus. Mechanism of uptake and relative contribution of radionuclide adsorption and absorption

    International Nuclear Information System (INIS)

    Nucho, R.; Baudin, J.P.

    1989-06-01

    In this paper are presented the results of various 60 Co accumulation and depuration experiments, carried out to assess the respective contributions of passive and active processes in the radionuclide uptake by Scenedesmus obliquus. The experiments were conduced on living illuminated cells, living cells maintained in darkness and dead cells. Exposure study shows that living illuminated cells and dead cells incorporated the same amount of available 60 Co, in the order of 65%. In contrast, the radionuclide uptake by cells in darkness was very lower. Depuration experiments show that radiocobalt release by living illuminated cells and dead cells is an exponential process including two phases. The first, during which the decrease of the radioactivity was about 80%, corresponds to elimination of the 60 Co adsorbed on the cell walls. During the second phase, the slight decrease of the radioactivity results from the intracellular 60 Co desorption. The addition of EDTA in the depuration culture medium results in an almost instantaneous loss of 80% of the accumulated radionuclide. The results clearly indicate that 60 Co uptake is mainly a passive phenomenon, since adsorption accounts for 80% of the accumulation and passive diffusion for about 10%. Metabolic assimilation contributes for a weak part [fr

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

    African Journals Online (AJOL)

    Proff.Adewunmi

    dihydroxy-lanosta-8-ene was also isolated from the bulbs. The ... Fresh bulbs from C. obliquus were purchased at the Berea market in Durban and identified by a curator from the School of Biological and. Conservation Sciences, UKZN, Westville ...

  17. 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).

  18. 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.

  19. Assessing microalgae biorefinery routes for the production of biofuels via hydrothermal liquefaction.

    Science.gov (United States)

    López Barreiro, Diego; Samorì, Chiara; Terranella, Giuseppe; Hornung, Ursel; Kruse, Andrea; Prins, Wolter

    2014-12-01

    The interest in third generation biofuels from microalgae has been rising during the past years. Meanwhile, it seems not economically feasible to grow algae just for biofuels. Co-products with a higher value should be produced by extracting a particular algae fraction to improve the economics of an algae biorefinery. The present study aims at analyzing the influence of two main microalgae components (lipids and proteins) on the composition and quantity of biocrude oil obtained via hydrothermal liquefaction of two strains (Nannochloropsis gaditana and Scenedesmus almeriensis). The algae were liquefied as raw biomass, after extracting lipids and after extracting proteins in microautoclave experiments at different temperatures (300-375°C) for 5 and 15min. The results indicate that extracting the proteins from the microalgae prior to HTL may be interesting to improve the economics of the process while at the same time reducing the nitrogen content of the biocrude oil. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. 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.

  1. Toxic Effects of Fungicides (Penconazole and Triadimenol) on Growth and Protein Amount of Scenedesmus acutus

    International Nuclear Information System (INIS)

    Agirman, N.; Bedil, B.; Kendirlioglu, G.; Cetin, A. K.

    2015-01-01

    In this work, the effects of penconazole and triadimenol to protein amount and growth of the microalgae Scenedesmus acutus were investigated. The culture of S. acutus was exposed to dissimilar concentrations of penconazole and triadimenol (1, 3, 6, 10 and 15 meu g/L) in the climate chamber at 23 ± 1 degree C and 16:8 photoperiod. Cell numbers and growth rates in liquid cultures of S. acutus were calculated for a period of four days. The results indicated toxic effects of penconazole and triadimenol on growth and protein amount of S. acutus. The protein amount and cell number of S. acutus in cultures treated with penconazole and triadimenol were rapidly decreasing at second day. (author)

  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. 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

    2018-03-01

    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: KNO 3 , urea, NaNO 3 , (NH 4 ) 2 CO 3 , and NH 4 NO 3 . 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/(m 2  day) and 31.1%, respectively. With attached cultivation, the highest biomass of 9.4 g/m 2 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.

  4. INHIBITORY EFFECT OF PIGMENT EXTRACT FROM SCENEDESMUS SP. ON FOOD SPIKED WITH FOODBORNE STAPHYLOCOCCUS AUREUS

    Directory of Open Access Journals (Sweden)

    Aisha

    2017-01-01

    Full Text Available Foodborne diseases are a recognized problem worldwide and the search is on to discover novel antimicrobial agents from natural sources that can replace the use of synthetic antimicrobial compounds. One of such sources are microalgae. The antibacterial efficacy of pigment extract from Scenedesmus sp. was tested against foodborne Staphylococcusaureus. The extract was prepared using 90% acetone and varying amounts was added to food suspension spiked with a known volume of the bacteria. Antibacterial activity was observed and evaluated through bacterial colony counts. Uncountable bacterial colonies were observed in the sample with 0.41 mg/ml and 0.81 mg/ml concentration of pigment extract as they were TMTC and there was no growth of bacterial colonies in samples with 2.83 mg/ml - 4.05 mg/ml concentration of pigment extract.The results of this study suggest that Scenedesmus sp. is a potential source of antibacterial compounds for food applications as an additive.

  5. 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/(m 2  × s) average incident light intensities and 1.25% diluted anaerobic digestate at 234 and 384 μmol/(m 2  × s) average incident light intensities. The maximum biomass concentration was 446 mg/L which was achieved in the 2.5% dilution and 454 μmol/(m 2  × 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.

  6. Adaptation of microalgae to a gradient of continuous petroleum contamination

    International Nuclear Information System (INIS)

    Carrera-Martinez, Daniel; Mateos-Sanz, Aranzazu; Lopez-Rodas, Victoria; Costas, Eduardo

    2011-01-01

    In order to study adaptation of microalgae to petroleum contamination, we have examined an environmental stress gradient by crude oil contamination in the Arroyo Minero River (AMR), Argentina. Underground crude oil has constantly leaked out since 1915 as a consequence of test drilling for possible petroleum exploitation. Numerous microalgae species proliferated in AMR upstream of the crude oil spill. In contrast, only four microalgal species were detected in the crude oil spill area. Species richness increases again downstream. Microalgae biomass in the crude oil spill area is dominated by a mesophile species, Scenedesmus sp. Effects of oil samples from AMR spill on photosynthetic performance and growth were studied using laboratory cultures of two Scenedesmus sp. strains. One strain (Se-co) was isolated from the crude oil spill area. The other strain (Se-pr) was isolated from a pristine area without petroleum contamination. Crude oil has undetectable effects on Se-co strain. In contrast crude oil rapidly destroys Se-pr strain. However, Se-pr strain can adapt to low doses of petroleum (≤3% v/v total hydrocarbons/water) by means of physiological acclimatization. In contrast, only rare crude oil-resistant mutants are able to grow under high levels of crude oil (≥10% v/v total hydrocarbons/water). These crude oil-resistant mutants have arisen through rare spontaneous mutations that occur prior to crude oil exposure. Species richness in different areas of AMR is closely connected to the kind of mechanism (genetic adaptation vs. physiological acclimatization) that allows adaptation. Resistant-mutants are enough to assure the survival of microalgal species under catastrophic crude oil spill.

  7. Adaptation of microalgae to a gradient of continuous petroleum contamination

    Energy Technology Data Exchange (ETDEWEB)

    Carrera-Martinez, Daniel; Mateos-Sanz, Aranzazu [AlgasGen Biotecnologia, EBT-UCM, Facultad de Veterinaria, Universidad Complutense de Madrid, Puerta de Hierro s/n, E-28040 Madrid (Spain); Lopez-Rodas, Victoria [AlgasGen Biotecnologia, EBT-UCM, Facultad de Veterinaria, Universidad Complutense de Madrid, Puerta de Hierro s/n, E-28040 Madrid (Spain); Genetica, Facultad de Veterinaria, Universidad Complutense de Madrid, Puerta de Hierro s/n, E-28040 Madrid (Spain); Costas, Eduardo, E-mail: ecostas@vet.ucm.es [AlgasGen Biotecnologia, EBT-UCM, Facultad de Veterinaria, Universidad Complutense de Madrid, Puerta de Hierro s/n, E-28040 Madrid (Spain); Genetica, Facultad de Veterinaria, Universidad Complutense de Madrid, Puerta de Hierro s/n, E-28040 Madrid (Spain)

    2011-01-25

    In order to study adaptation of microalgae to petroleum contamination, we have examined an environmental stress gradient by crude oil contamination in the Arroyo Minero River (AMR), Argentina. Underground crude oil has constantly leaked out since 1915 as a consequence of test drilling for possible petroleum exploitation. Numerous microalgae species proliferated in AMR upstream of the crude oil spill. In contrast, only four microalgal species were detected in the crude oil spill area. Species richness increases again downstream. Microalgae biomass in the crude oil spill area is dominated by a mesophile species, Scenedesmus sp. Effects of oil samples from AMR spill on photosynthetic performance and growth were studied using laboratory cultures of two Scenedesmus sp. strains. One strain (Se-co) was isolated from the crude oil spill area. The other strain (Se-pr) was isolated from a pristine area without petroleum contamination. Crude oil has undetectable effects on Se-co strain. In contrast crude oil rapidly destroys Se-pr strain. However, Se-pr strain can adapt to low doses of petroleum ({<=}3% v/v total hydrocarbons/water) by means of physiological acclimatization. In contrast, only rare crude oil-resistant mutants are able to grow under high levels of crude oil ({>=}10% v/v total hydrocarbons/water). These crude oil-resistant mutants have arisen through rare spontaneous mutations that occur prior to crude oil exposure. Species richness in different areas of AMR is closely connected to the kind of mechanism (genetic adaptation vs. physiological acclimatization) that allows adaptation. Resistant-mutants are enough to assure the survival of microalgal species under catastrophic crude oil spill.

  8. Design and development of polyamine polymer for harvesting microalgae for biofuels production

    International Nuclear Information System (INIS)

    Gupta, S.K.; Kumar, M.; Guldhe, A.; Ansari, F.A.; Rawat, I.; Kanney, K.; Bux, F.

    2014-01-01

    Highlights: • A low cost, high molecular weight cationic polymer was designed and developed for microalgal harvesting. • The polyamine polymer showed high flocculation efficiency for Scenedesmus sp. in comparison with chitosan and alum. • Such polymers could be preferred over other flocculants for microalgal harvesting for low value products such as biodiesel. • The polymer has not shown any deteriorating effect on lipid recovery and FAME profile of Scenedesmus sp. • Polyamine flocculant could be a cost effective option for harvesting of microalgal biomass for sustainable energy production. - Abstract: Research findings of the past few decades on the cultivation of microalgae for biodiesel production from laboratory to pilot scale microalgal cultivation have translated into empirical hope of developing an eco-friendly biofuel from algae. As far as economic sustainability is concerned, harvesting of microalgae is one of the most energy extensive processes and thus a major challenge, being faced by this industry. In our study, we designed and developed a quaternary ammonium salt based cationic polymer and evaluated its effectiveness for freshwater microalgae harvesting. An epichlorohydrin-n,n-diisopropylamine-dimethylamine polymer with high viscosity (1040 cps) was synthesized. The flocculation performance of this polyamine polymer was evaluated in terms of biomass recovery efficiency of microalgae (Scenedesmus sp.), its effect on lipid yield and composition. The results revealed that due to high molecular weight, the biomass recovery efficiency of the polymer was achieved >90% at a very small dose of 8 mg/L whereas similar biomass recovery efficiency of chitosan and alum were achieved at 80 and 250 mg/L respectively. The presence of functional quaternary amine and hydroxyl groups played an important role in electric charge neutralization of microalgal cells, hence the improved microalgal flocculation performance in comparison to the natural flocculants but

  9. Microalgae: biofuel production

    Directory of Open Access Journals (Sweden)

    Babita Kumari

    2013-04-01

    Full Text Available In the present day, microalgae feedstocks are gaining interest in energy scenario due to their fast growth potential coupled with relatively high lipid, carbohydrate and nutrients contents. All of these properties render them an excellent source for biofuels such as biodiesel, bioethanol and biomethane; as well as a number of other valuable pharmaceutical and nutraceutical products. The present review is a critical appraisal of the commercialization potential of microalgae biofuels. The available literature on various aspects of microalgae for e.g. its cultivation, life cycle assessment, and conceptualization of an algal biorefinery, has been done. The evaluation of available information suggests the operational and maintenance cost along with maximization of oil-rich microalgae production is the key factor for successful commercialization of microalgae-based fuels.

  10. 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.

  11. Bioprocessos para remoção de dióxido de carbono e óxido de nitrogênio por micro-algas visando a utilização de gases gerados durante a combustão do carvão Bioprocesses for removal of carbon dioxide and nitrogen oxide by microalgae for the utilization of gas generated during coal burning

    Directory of Open Access Journals (Sweden)

    Michele Greque de Morais

    2008-01-01

    Full Text Available The aim of this work was to study the removal of CO2 and NO by microalgae and to evaluate the kinetic characteristics of the cultures. Spirulina sp. showed µmax and Xmax (0.11 d-1, 1.11 g L-1 d-1 when treated with CO2 and NaNO3. The maximum CO2 removal was 22.97% for S. obliquus treated with KNO3 and atmospheric CO2. The S. obliquus showed maximum NO removal (21.30% when treated with NO and CO2. Coupling the cultivation of these microalgae with the removal of CO2 and NO has the potential not only to reduce the costs of culture media but also to offset carbon and nitrogen emissions.

  12. 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 (Y x/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.

  13. 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.

  14. 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

  15. 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.

  16. Biotechnological applications of microalgae

    OpenAIRE

    Wan-Loy Chu

    2012-01-01

    Microalgae are important biologicalresources that have a wide range of biotechnologicalapplications. Due to their high nutritional value,microalgae such as Spirulina and Chlorella are beingmass cultured for health food. A variety of high-valueproducts including polyunsaturated fatty acids (PUFA),pigments such as carotenoids and phycobiliproteins, andbioactive compounds are useful as nutraceuticals andpharmaceuticals, as well as for industrial applications. Interms of environmental biotechnolo...

  17. Pilot project at Hazira, India, for capture of carbon dioxide and its biofixation using microalgae.

    Science.gov (United States)

    Yadav, Anant; Choudhary, Piyush; Atri, Neelam; Teir, Sebastian; Mutnuri, Srikanth

    2016-11-01

    The objective of the present study was to set up a small-scale pilot reactor at ONGC Hazira, Surat, for capturing CO 2 from vent gas. The studies were carried out for CO 2 capture by either using microalgae Chlorella sp. or a consortium of microalgae (Scenedesmus quadricauda, Chlorella vulgaris and Chlorococcum humicola). The biomass harvested was used for anaerobic digestion to produce biogas. The carbonation column was able to decrease the average 34 vol.% of CO 2 in vent gas to 15 vol.% of CO 2 in the outlet gas of the carbonation column. The yield of Chlorella sp. was found to be 18 g/m 2 /day. The methane yield was 386 l CH 4 /kg VS fed of Chlorella sp. whereas 228 l CH 4 /kg VS fed of the consortium of algae.

  18. Influence of crude glycerol on the biomass and lipid content of microalgae

    International Nuclear Information System (INIS)

    Choi, Hee-Jeong; Yu, Sung-Whan

    2015-01-01

    The growth of the algae Chlorella vulgaris, Botryococcus braunii and Scenedesmus sp. under mixotrophic conditions in the presence of different concentrations of crude glycerol was evaluated with the objective of increasing the biomass growth and algal oil content. A high biomass concentration was characteristic of these strains when grown on crude glycerol compared to autotrophic growth, and 5 g/L glycerol yielded the highest biomass concentration for these strains. Mixotrophic conditions improved both the growth of the microalgae and the accumulation of triacylglycerols (TAGs). The maximum amount of TAGs in the algae biomass was obtained in the 5 g/L glycerol growth medium. The fatty acid profiles of the oil for the cultures met the necessary requirements and the strains are promising resources for biofuel production. Keywords: biomass; glycerol; microalgae; mixotrophic; oil content

  19. 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 CO 2 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% CO 2 . 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 CO 2 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.

  20. Carotenoids in Microalgae.

    Science.gov (United States)

    Henríquez, Vitalia; Escobar, Carolina; Galarza, Janeth; Gimpel, Javier

    Carotenoids are a class of isoprenoids synthesized by all photosynthetic organisms as well as by some non-photosynthetic bacteria and fungi with broad applications in food, feed and cosmetics, and also in the nutraceutical and pharmaceutical industries. Microalgae represent an important source of high-value products, which include carotenoids, among others. Carotenoids play key roles in light harvesting and energy transfer during photosynthesis and in the protection of the photosynthetic apparatus against photooxidative damage. Carotenoids are generally divided into carotenes and xanthophyls, but accumulation in microalgae can also be classified as primary (essential for survival) and secondary (by exposure to specific stimuli).In this chapter, we outline the high value carotenoids produced by commercially important microalgae, their production pathways, the improved production rates that can be achieved by genetic engineering as well as their biotechnological applications.

  1. Inducción de la producción de lípidos totales en microalgas sometidas a estrés nutritivo

    Directory of Open Access Journals (Sweden)

    Marianela Cobos Ruiz

    2016-01-01

    Full Text Available Se evaluó la producción de lípidos totales en cinco especies de microalgas inducidas por la ausencia de nitrógeno. Las microalgas empleadas fueron Ankistrodesmus sp., Ankistrodesmus nannoselene, Chlorella sp., Scenedesmus sp. y Scenedesmus quadricauda. Estas especies fueron cultivadas en medio CHU10 con y sin nitrógeno. El tiempo de evaluación fue de seis días, determinándose diariamente la densidad microalgal mediante recuento en cámara de Neubahuer. Se determinó la tasa de crecimiento, la biomasa microalgal y el porcentaje de lípidos totales. Los lípidos totales fueron extraídos con solución Cloroformo:metanol (2:1. Los resultados indicaron que las especies con mayor producción de lípidos totales fueron Ankistrodesmus sp. (263,6 mg/g biomasa seca, A. nannoselene (316 mg/g biomasa seca y Scenedesmus sp. (243,3 mg/g biomasa seca al ser cultivadas en medios sin nitrógeno. Scenedesmus quadricauda y Chlorella sp., fueron las especies que mostraron mayor producción de biomasa seca (159,1 mg/g biomasa seca y 221,1 mg/g biomasa seca respectivamente en medios con nitrógeno. La tasa de crecimiento fue variable entre las especies cultivadas en ambas condiciones. En conclusión, Ankistrodesmus sp., mostró la mayor tasa de crecimiento (0,77 dia-1 en medio sin nitrógeno. Bajo las mismas condiciones de cultivo, Scenedesmus sp. obtuvo la mayor producción de biomasa en peso seco (174,7 mg/l y Ankistrodesmus nannoselene acumuló el mayor porcentaje de lípidos totales.

  2. The adsorption kinetics of metal ions onto different microalgae and siliceous earth.

    Science.gov (United States)

    Schmitt, D; Müller, A; Csögör, Z; Frimmel, F H; Posten, C

    2001-03-01

    In the present work the adsorption kinetics of the six metal ions aluminum, zinc, mercury, lead, copper, and cadmium onto living microalgae were measured. The freshwater green microalga Scenedesmus subspicatus, the brackish water diatom Cyclotella cryptica, the seawater diatom Phaeodactylum tricornutum, and the seawater red alga Porphyridium purpureum were the subject of investigation. In most cases the adsorption rate of the metals could be well described by using the equation of the Langmuir adsorption rate expression. Inverse parameter estimation allowed the determination of the rate constants of the adsorption process and the maximum metal content of the algae. The highest values for the rate constant were obtained for Porphyridium purpureum followed by Phaeodactylum tricornutum. High values for the maximum content were obtained for Cyclotella cryptica and Scenedesmus subspicatus. The maximum rate constant was 24.21 h-1 for the adsorption of Hg to Porphyridium purpureum whereas the maximum metal content (0.243 g g-1) was obtained for Zn on Cyclotella cryptica. A comparison of these values with those obtained for the mineral siliceous earth exhibiting low maximum content and high adsorption rates reveals that the mechanism of adsorption onto the algae is a mixture of adsorption and accumulation.

  3. Production of biodiesel from microalgae

    Directory of Open Access Journals (Sweden)

    Danilović Bojana R.

    2014-01-01

    Full Text Available In recent years, more attention has been paid to the use of third generation feedstocs for the production of biodiesel. One of the most promising sources of oil for biodiesel production are microalgae. They are unicellular or colonial photosynthetic organisms, with permanently increasing industrial application in the production of not only chemicals and nutritional supplements but also biodiesel. Biodiesel productivity per hectare of cultivation area can be up to 100 times higher for microalgae than for oil crops. Also, microalgae can grow in a variety of environments that are often unsuitable for agricultural purposes. Microalgae oil content varies in different species and can reach up to 77% of dry biomass, while the oil productivity by the phototrophic cultivation of microalgae is up to 122 mg/l/d. Variations of the growth conditions and the implementation of the genetic engineering can induce the changes in the composition and productivity of microalgal oil. Biodiesel from microalgae can be produced in two ways: by transesterification of oil extracted from biomass or by direct transesterification of algal biomass (so called in situ transesterification. This paper reviews the curent status of microalgae used for the production of biodiesel including their isolation, cultivation, harvesting and conversion to biodiesel. Because of high oil productivity, microalgae will play a significant role in future biodiesel production. The advantages of using microalgae as a source for biofuel production are increased efficiency and reduced cost of production. Also, microalgae do not require a lot of space for growing and do not have a negative impact on the global food and water supplies. Disadvantages of using microalgae are more difficult separation of biomass and the need for further research to develop standardized methods for microalgae cultivation and biodiesel production. Currently, microalgae are not yet sustainable option for the commercial

  4. Biofuels from Microalgae

    NARCIS (Netherlands)

    Barbosa, M.J.; Wijffels, R.H.

    2013-01-01

    Microalgae are a promising feedstock for sustaineble production of biofuela due to their unique capacity to reach high lipid productivities. Although the promises are there, production costs and energy requirements are high and the technology is still ammature for the production of bulk products. It

  5. Economics of microalgae production

    NARCIS (Netherlands)

    Acién, F.G.; Molina, E.; Fernández-Sevilla, J.M.; Barbosa, M.; Gouveia, L.; Sepúlveda, C.; Bazaes, J.; Arbib, Z.

    2017-01-01

    The economic analysis of biomass production is a critical step in ensuring the success of any microalgae-based industry. Until recently, only small-scale facilities of less than 10. ha have been in operation, but now large-scale facilities of more than 200. ha are being built and operated.

  6. Food commodities from microalgae

    NARCIS (Netherlands)

    Draaisma, R.B.; Wijffels, R.H.; Slegers, P.M.; Brentner, L.B.; Roy, A.; Barbosa, M.J.

    2013-01-01

    The prospect of sustainable production of food ingredients from photoautotrophic microalgae was reviewed. Clearly, there is scope for microalgal oils to replace functions of major vegetable oils, and in addition to deliver health benefits to food products. Furthermore, with a limited production

  7. Functional ingredients from microalgae

    NARCIS (Netherlands)

    Buono, S.; Langellotti, A.L.; Martello, A.; Rinna, F.; Fogliano, V.

    2014-01-01

    A wide variety of natural sources are under investigation to evaluate their possible use for new functional ingredient formulation. Some records attested the traditional and ancient use of wild harvested microalgae as human food but their cultivation for different purposes started about 40 years

  8. Seasonal biodiversity and ecological studies on the epiphytic microalgae communities in polluted and unpolluted aquatic ecosystem at Assiut, Egypt

    Directory of Open Access Journals (Sweden)

    Adam Mahmoud S.

    2017-12-01

    Full Text Available A qualitative and quantitative study on epiphytic microalgae was carried out seasonally from November 2015 to August 2016 to follow up their community structures on aquatic macrophytes related to some physico-chemical properties of two polluted and unpolluted water bodies at Assiut, Egypt. A total of 169 species related to 64 genera of epiphytic microalgae were recorded. The most dominant algal group was Bacillariophyceae (43.2%, followed by Chlorophyceae (34.91%, Cyanophyceae (20.71% and Euglenophyceae (1.18%. The total number of epiphytic algae fluctuated between 11.1 × 104 ind.g-1 plant dry wt. on Phragmites australis in summer at Nazlet Abdellah (polluted site and 10.02 × 107 ind.g-1 plant dry wt. on Myriophyllum spicatum in winter at El-Wasta (unpolluted site. Some epiphytic microalgae were dominant as Pseudanabaena limnetica, Calothrix braunii, Scenedesmus acutus, and Ulnaria ulna. Others were specific on certain macrophytes as Aphanocapsa thermalis and Ulothrix sp., which grow on Phragmites australis, while Synechocystis minuscula attached itself on Myriophyllum spicatum. Analysis of PERMANOVA showed that the most important factors that induced the variation in epiphytic microalgae were the temporal variation and host plant. Water temperature, pH, nitrate, chloride, phosphate and total dissolved salts were the highest abiotic factors correlated with the variation in composition of epiphytic microalgae.

  9. Assessment of the mechanisms involved in the removal of emerging contaminants by microalgae from wastewater: a laboratory scale study.

    Science.gov (United States)

    Matamoros, Víctor; Uggetti, Enrica; García, Joan; Bayona, Josep M

    2016-01-15

    Aerated batch reactors (2.5L) fed either with urban or synthetic wastewater were inoculated with microalgae (dominated by Chlorella sp. and Scenedesmus sp.) to remove caffeine, ibuprofen, galaxolide, tributyl phosphate, 4-octylphenol, tris(2-chloroethyl) phosphate and carbamazepine for 10 incubation days. Non-aerated and darkness reactors were used as controls. Microalgae grew at a rate of 0.25 d(-1) with the complete removal of N-NH4 during the course of the experiment. After 10 incubation days, up to 99% of the microcontaminants with a Henry's law constant higher than 3 10(-1) Pa m(3) mol(-1) (i.e., 4-octylphenol, galaxolide, and tributyl phosphate) were removed by volatilization due to the effect of air stripping. Whereas biodegradation was effective for removing ibuprofen and caffeine, carbamazepine and tris(2-chloroethyl) phosphate behaved as recalcitrant compounds. The use of microalgae was proved to be relevant for increasing the biodegradation removal efficiency of ibuprofen by 40% and reducing the lag phase of caffeine by 3 days. Moreover, the enantioselective biodegradation of S-ibuprofen suggested a biotic prevalent removal process, which was supported by the identification of carboxy-ibuprofen and hydroxy-ibuprofen. The results from microalgae reactors fed with synthetic wastewater showed no clear evidences of microalgae uptake of any of the studied microcontaminants. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. 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.

  11. 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.

  12. Advances in editing microalgae genomes

    OpenAIRE

    Daboussi, Fayza

    2017-01-01

    There have been significant advances in microalgal genomics over the last decade. Nevertheless, there are still insufficient tools for the manipulation of microalgae genomes and the development of microalgae as industrial biofactories. Several research groups have recently contributed to progress by demonstrating that particular nucleases can be used for targeted and stable modifications of the genomes of some microalgae species. The nucleases include Meganucleases, Zinc Finger nucleases, TAL...

  13. Fuels from microalgae

    Energy Technology Data Exchange (ETDEWEB)

    1989-06-01

    Many species of aquatic plants can provide a source of renewable energy. Some species of microalgae, in particular, produce lipids -- oils that can be extracted and converted to a diesel fuel substitute or to gasoline. Since 1979 the Aquatic Species Program element of the Biofuels Program, has supported fundamental and applied research to develop the technology for using this renewable energy resource. This document, produced by the Solar Technical Information Program, provides an overview of the DOE/SERI Aquatic Species Program element. Chapter 1 is an introduction to the program and to the microalgae. Chapter 2 is an overview of the general principles involved in making fuels from microalgae. It also outlines the technical challenges to producing economic, high-energy transportation fuels. Chapter 3 provides an overview of the Algal Production and Economic Model (APEM). This model was developed by researchers within the program to identify aspects of the process critical to performance with the greatest potential to reduce costs. The analysis using this model has helped direct research sponsored by the program. Finally, Chapter 4 provides an overview of the Aquatic Species Program and describes current research. 28 refs., 17 figs.

  14. Phototrophic pigment production with microalgae

    NARCIS (Netherlands)

    Mulders, K.J.M.

    2014-01-01

    Abstract

    Microalgal pigments are regarded as natural alternatives for food colorants. To facilitate optimization of microalgae-based pigment production, this thesis aimed to obtain key insights in the pigment metabolism of phototrophic microalgae, with the main focus on secondary

  15. Multi-Product Microalgae Biorefineries

    NARCIS (Netherlands)

    Lam, 't G.P.; Vermuë, M.H.; Eppink, M.H.M.; Wijffels, R.H.; Berg, van den C.

    2018-01-01

    Although microalgae are a promising biobased feedstock, industrial scale production is still far off. To enhance the economic viability of large-scale microalgae processes, all biomass components need to be valorized, requiring a multi-product biorefinery. However, this concept is still too

  16. High protein- and high lipid-producing microalgae from Outback Australia as potential feedstock for animal feed and biodiesel

    Directory of Open Access Journals (Sweden)

    Van Thang eDuong

    2015-05-01

    Full Text Available Microalgal biomass can be used for biodiesel, feed and food production. Collection and identification of local microalgal strains in the Northern Territory – Australia was conducted to identify strains with high protein and lipid contents as potential feedstock for animal feed and biodiesel production, respectively. A total of 36 strains were isolated from 13 samples collected from a variety of freshwater locations, such as dams, ponds and streams and subsequently classified by 18S rDNA sequencing. All of the strains were green microalgae and predominantly belong to Chlorella sp., Scenedesmus sp., Desmodesmus sp., Chlamydomonas sp., Pseudomuriella sp., Tetraedron caudatum, Graesiella emersonii and Mychonastes timauensis. Among the fastest growing strains, Scenedesmus sp. NT1d possessed the highest content of protein; reaching up to 33% of its dry weight. In terms of lipid production, Chlorella sp. NT8a and Scenedesmus dimorphus NT8e produced the highest triglyceride contents of 116.9 µg mL-1 culture and 99.13 µg mL-1, respectively, as measured by gas chromatography-mass spectroscopy (GC-MS of fatty acid methyl esters (FAMEs. These strains may present suitable candidates for biodiesel production after further optimization of culturing conditions, while their protein-rich biomass could be used for animal feed.

  17. Screening microalgae isolated from urban storm- and wastewater systems as feedstock for biofuel.

    Science.gov (United States)

    Massimi, Rebecca; Kirkwood, Andrea E

    2016-01-01

    Exploiting microalgae as feedstock for biofuel production is a growing field of research and application, but there remain challenges related to industrial viability and economic sustainability. A solution to the water requirements of industrial-scale production is the use of wastewater as a growth medium. Considering the variable quality and contaminant loads of wastewater, algal feedstock would need to have broad tolerance and resilience to fluctuating wastewater conditions during growth. As a first step in targeting strains for growth in wastewater, our study isolated microalgae from wastewater habitats, including urban stormwater-ponds and a municipal wastewater-treatment system, to assess growth, fatty acids and metal tolerance under standardized conditions. Stormwater ponds in particular have widely fluctuating conditions and metal loads, so microalgae from this type of environment may have desirable traits for growth in wastewater. Forty-three algal strains were isolated in total, including several strains from natural habitats. All strains, with the exception of one cyanobacterial strain, are members of the Chlorophyta, including several taxa commonly targeted for biofuel production. Isolates were identified using taxonomic and 18S rRNA sequence methods, and the fastest growing strains with ideal fatty acid profiles for biodiesel production included Scenedesmus and Desmodesmus species (Growth rate (d(-1)) > 1). All isolates in a small, but diverse taxonomic group of test-strains were tolerant of copper at wastewater-relevant concentrations. Overall, more than half of the isolated strains, particularly those from stormwater ponds, show promise as candidates for biofuel feedstock.

  18. Screening microalgae isolated from urban storm- and wastewater systems as feedstock for biofuel

    Directory of Open Access Journals (Sweden)

    Rebecca Massimi

    2016-09-01

    Full Text Available Exploiting microalgae as feedstock for biofuel production is a growing field of research and application, but there remain challenges related to industrial viability and economic sustainability. A solution to the water requirements of industrial-scale production is the use of wastewater as a growth medium. Considering the variable quality and contaminant loads of wastewater, algal feedstock would need to have broad tolerance and resilience to fluctuating wastewater conditions during growth. As a first step in targeting strains for growth in wastewater, our study isolated microalgae from wastewater habitats, including urban stormwater-ponds and a municipal wastewater-treatment system, to assess growth, fatty acids and metal tolerance under standardized conditions. Stormwater ponds in particular have widely fluctuating conditions and metal loads, so microalgae from this type of environment may have desirable traits for growth in wastewater. Forty-three algal strains were isolated in total, including several strains from natural habitats. All strains, with the exception of one cyanobacterial strain, are members of the Chlorophyta, including several taxa commonly targeted for biofuel production. Isolates were identified using taxonomic and 18S rRNA sequence methods, and the fastest growing strains with ideal fatty acid profiles for biodiesel production included Scenedesmus and Desmodesmus species (Growth rate (d−1 > 1. All isolates in a small, but diverse taxonomic group of test-strains were tolerant of copper at wastewater-relevant concentrations. Overall, more than half of the isolated strains, particularly those from stormwater ponds, show promise as candidates for biofuel feedstock.

  19. TiO2, SiO2 and ZrO2 Nanoparticles Synergistically Provoke Cellular Oxidative Damage in Freshwater Microalgae

    Directory of Open Access Journals (Sweden)

    Yinghan Liu

    2018-02-01

    Full Text Available Metal-based nanoparticles (NPs are the most widely used engineered nanomaterials. The individual toxicities of metal-based NPs have been plentifully studied. However, the mixture toxicity of multiple NP systems (n ≥ 3 remains much less understood. Herein, the toxicity of titanium dioxide (TiO2 nanoparticles (NPs, silicon dioxide (SiO2 NPs and zirconium dioxide (ZrO2 NPs to unicellular freshwater algae Scenedesmus obliquus was investigated individually and in binary and ternary combination. Results show that the ternary combination systems of TiO2, SiO2 and ZrO2 NPs at a mixture concentration of 1 mg/L significantly enhanced mitochondrial membrane potential and intracellular reactive oxygen species level in the algae. Moreover, the ternary NP systems remarkably increased the activity of the antioxidant defense enzymes superoxide dismutase and catalase, together with an increase in lipid peroxidation products and small molecule metabolites. Furthermore, the observation of superficial structures of S. obliquus revealed obvious oxidative damage induced by the ternary mixtures. Taken together, the ternary NP systems exerted more severe oxidative stress in the algae than the individual and the binary NP systems. Thus, our findings highlight the importance of the assessment of the synergistic toxicity of multi-nanomaterial systems.

  20. 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.

  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. Cell disruption for microalgae biorefineries.

    Science.gov (United States)

    Günerken, E; D'Hondt, E; Eppink, M H M; Garcia-Gonzalez, L; Elst, K; Wijffels, R H

    2015-01-01

    Microalgae are a potential source for various valuable chemicals for commercial applications ranging from nutraceuticals to fuels. Objective in a biorefinery is to utilize biomass ingredients efficiently similarly to petroleum refineries in which oil is fractionated in fuels and a variety of products with higher value. Downstream processes in microalgae biorefineries consist of different steps whereof cell disruption is the most crucial part. To maintain the functionality of algae biochemicals during cell disruption while obtaining high disruption yields is an important challenge. Despite this need, studies on mild disruption of microalgae cells are limited. This review article focuses on the evaluation of conventional and emerging cell disruption technologies, and a comparison thereof with respect to their potential for the future microalgae biorefineries. The discussed techniques are bead milling, high pressure homogenization, high speed homogenization, ultrasonication, microwave treatment, pulsed electric field treatment, non-mechanical cell disruption and some emerging technologies. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Microalgae biofuel potentials (review).

    Science.gov (United States)

    Ghasemi, Y; Rasoul-Amini, S; Naseri, A T; Montazeri-Najafabady, N; Mobasher, M A; Dabbagh, F

    2012-01-01

    With the decrease of fossil based fuels and the environmental impact of them over the planet, it seems necessary to seek the sustainable sources of clean energy. Biofuels, is becoming a worldwide leader in the development of renewable energy resources. It is worthwhile to say that algal biofuel production is thought to help stabilize the concentration of carbon dioxide in the atmosphere and decrease global warming impacts. Also, among algal fuels' attractive characteristics, algal biodiesel is non toxic, with no sulfur, highly biodegradable and relatively harmless to the environment if spilled. Algae are capable of producing in excess of 30 times more oil per acre than corn and soybean crops. Currently, algal biofuel production has not been commercialized due to high costs associated with production, harvesting and oil extraction but the technology is progressing. Extensive research was conducted to determine the utilization of microalgae as an energy source and make algae oil production commercially viable.

  4. Structural characterization of bioactive heteropolysaccharides from the medicinal fungus Inonotus obliquus (Chaga)

    DEFF Research Database (Denmark)

    Wold, Christian Winther; Kjeldsen, Christian; Corthay, Alexandre

    2018-01-01

    The aim of this paper was to perform a comprehensive characterization of polysaccharides isolated from the interior (IOI) and exterior (IOE) parts of the fungus Inonotus obliquus. Pre-extraction with DCM and MeOH, followed by water and alkali extraction and ethanol precipitation gave two water ex...

  5. Patellar stabilization: a quantitative evaluation of the vastus medialis obliquus muscle

    NARCIS (Netherlands)

    Raimondo, R. A.; Ahmad, C. S.; Blankevoort, L.; April, E. W.; Grelsamer, R. P.; Henry, J. H.

    1998-01-01

    Twenty-one cadaveric knees were dissected to analyze the functional anatomy of the vastus medialis complex (VMC), which is composed of the vastus medialis obliquus (VMO) and the vastus medialis longus (VML) muscles. The physiologic cross-sectional area of the VMO for 20 of the knees was 29% of the

  6. A single-step method for rapid extraction of total lipids from green microalgae.

    Directory of Open Access Journals (Sweden)

    Martin Axelsson

    Full Text Available Microalgae produce a wide range of lipid compounds of potential commercial interest. Total lipid extraction performed by conventional extraction methods, relying on the chloroform-methanol solvent system are too laborious and time consuming for screening large numbers of samples. In this study, three previous extraction methods devised by Folch et al. (1957, Bligh and Dyer (1959 and Selstam and Öquist (1985 were compared and a faster single-step procedure was developed for extraction of total lipids from green microalgae. In the single-step procedure, 8 ml of a 2∶1 chloroform-methanol (v/v mixture was added to fresh or frozen microalgal paste or pulverized dry algal biomass contained in a glass centrifuge tube. The biomass was manually suspended by vigorously shaking the tube for a few seconds and 2 ml of a 0.73% NaCl water solution was added. Phase separation was facilitated by 2 min of centrifugation at 350 g and the lower phase was recovered for analysis. An uncharacterized microalgal polyculture and the green microalgae Scenedesmus dimorphus, Selenastrum minutum, and Chlorella protothecoides were subjected to the different extraction methods and various techniques of biomass homogenization. The less labour intensive single-step procedure presented here allowed simultaneous recovery of total lipid extracts from multiple samples of green microalgae with quantitative yields and fatty acid profiles comparable to those of the previous methods. While the single-step procedure is highly correlated in lipid extractability (r² = 0.985 to the previous method of Folch et al. (1957, it allowed at least five times higher sample throughput.

  7. Physicochemical analysis of cellulose from microalgae ...

    African Journals Online (AJOL)

    African Journal of Biotechnology ... Nannochloropsis gaditana is a microalgae belonging to the class of Eustigmatophyceae. This particular microalga is the most studied species. For its richness in lipids, it is used for the biodiesel production.

  8. Occurrence of high molecular weight lipids (C{sub 80+}) in the trilaminar outer cell walls of some freshwater microalgae. A reappraisal of algaenan structure

    Energy Technology Data Exchange (ETDEWEB)

    Allard, B.; Templier, J. [UMR CNRS, Paris (France). Laboratoire de Chimie Bioorganique et Organique Physique; Rager, M.-N. [UMR CNRS, Paris (France). Service RMN

    2002-07-01

    The purified cell walls of mother cells (CWM) were isolated from three strains of trilaminar sheath (TLS)- and algaenan-containing freshwater microalgae Chlorella emersonii, Tetraedron minimum and Scenedesmus communis. The chemical structures of CWM and algaenans were investigated by means of tetramethylammonium hydroxide (TMAH) hydrolysis and tetramethylammonium hydroxide thermochemolysis. The compounds released were characterised by {sup 1}H and {sup 13}C-NMR, gel permeation chromatography and desorption chemical ionisation mass spectrometry. The results show that the outer cell walls of the microalgae are constituted, at least in part, of linear (poly)esters containing extremely long chain alcohol and acid moieties (up to C{sub 80}) and that algaenans are mainly composed of extremely long chain (di)carboxylic acids up to C{sub 120}. The present results which are in direct contrast to the previous three-dimensional architecture proposed for algaenans, led us to re-interpret the algaenan structure. (Author)

  9. Microalgae harvesting techniques: A review.

    Science.gov (United States)

    Singh, Gulab; Patidar, S K

    2018-07-01

    Microalgae with wide range of commercial applications have attracted a lot of attention of the researchers in the last few decades. However, microalgae utilization is not economically sustainable due to high cost of harvesting. A wide range of solid - liquid separation techniques are available for microalgae harvesting. The techniques include coagulation and flocculation, flotation, centrifugation and filtration or a combination of various techniques. Despite the importance of harvesting to the economics and energy balance, there is no universal harvesting technique for microalgae. Therefore, this review focuses on assessing technical, economical and application potential of various harvesting techniques so as to allow selection of an appropriate technology for cost effectively harvesting of microalgae from their culture medium. Various harvesting and concentrating techniques of microalgae were reviewed to suggest order of suitability of the techniques for four main microalgae applications i.e biofuel, human and animal food, high valued products, and water quality restoration. For deciding the order of suitability, a comparative analysis of various harvesting techniques based on the six common criterions (i.e biomass quality, cost, biomass quantity, processing time, species specific and toxicity) has been done. Based on the order of various techniques vis-a-vis various criteria and preferred order of criteria for various applications, order of suitability of harvesting techniques for various applications has been decided. Among various harvesting techniques, coagulation and flocculation, centrifugation and filtration were found to be most suitable for considered applications. These techniques may be used alone or in combination for increasing the harvesting efficiency. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. 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

  11. 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

  12. 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.

  13. Assessment of the mechanisms involved in the removal of emerging contaminants by microalgae from wastewater: a laboratory scale study

    International Nuclear Information System (INIS)

    Matamoros, Víctor; Uggetti, Enrica; García, Joan; Bayona, Josep M.

    2016-01-01

    Highlights: • The effect of microalage on the removal of emerging contaminants has been evaluated. • Volatilization was relevant for compounds with a moderate Henry’s law constant. • Biodegradation was the main factor for the removal of caffeine and ibuprofen. • Ibuprofen enantioselective biodegradation was observed. • CA-ibuprofen and OH-ibuprofen followed the concentration decline of ibuprofen. - Abstract: Aerated batch reactors (2.5 L) fed either with urban or synthetic wastewater were inoculated with microalgae (dominated by Chlorella sp. and Scenedesmus sp.) to remove caffeine, ibuprofen, galaxolide, tributyl phosphate, 4-octylphenol, tris(2-chloroethyl) phosphate and carbamazepine for 10 incubation days. Non-aerated and darkness reactors were used as controls. Microalgae grew at a rate of 0.25 d −1 with the complete removal of N-NH 4 during the course of the experiment. After 10 incubation days, up to 99% of the microcontaminants with a Henry’s law constant higher than 3 10 −1 Pa m 3 mol −1 (i.e., 4-octylphenol, galaxolide, and tributyl phosphate) were removed by volatilization due to the effect of air stripping. Whereas biodegradation was effective for removing ibuprofen and caffeine, carbamazepine and tris(2-chloroethyl) phosphate behaved as recalcitrant compounds. The use of microalgae was proved to be relevant for increasing the biodegradation removal efficiency of ibuprofen by 40% and reducing the lag phase of caffeine by 3 days. Moreover, the enantioselective biodegradation of S-ibuprofen suggested a biotic prevalent removal process, which was supported by the identification of carboxy-ibuprofen and hydroxy-ibuprofen. The results from microalgae reactors fed with synthetic wastewater showed no clear evidences of microalgae uptake of any of the studied microcontaminants.

  14. Assessment of the mechanisms involved in the removal of emerging contaminants by microalgae from wastewater: a laboratory scale study

    Energy Technology Data Exchange (ETDEWEB)

    Matamoros, Víctor, E-mail: victor.matamoros@idaea.csic.es [Department of Environmental Chemistry, IDAEA–CSIC, c/Jordi Girona, 18-26, E-08034 Barcelona (Spain); Uggetti, Enrica; García, Joan [GEMMA—Group of Environmental Engineering and Microbiology, Department of Hydraulic, Maritime and Environmental Engineering, Universitat Politècnica de Catalunya BarcelonaTech, c/Jordi Girona, 1-3, Building D1, E-08034 Barcelona (Spain); Bayona, Josep M. [Department of Environmental Chemistry, IDAEA–CSIC, c/Jordi Girona, 18-26, E-08034 Barcelona (Spain)

    2016-01-15

    Highlights: • The effect of microalage on the removal of emerging contaminants has been evaluated. • Volatilization was relevant for compounds with a moderate Henry’s law constant. • Biodegradation was the main factor for the removal of caffeine and ibuprofen. • Ibuprofen enantioselective biodegradation was observed. • CA-ibuprofen and OH-ibuprofen followed the concentration decline of ibuprofen. - Abstract: Aerated batch reactors (2.5 L) fed either with urban or synthetic wastewater were inoculated with microalgae (dominated by Chlorella sp. and Scenedesmus sp.) to remove caffeine, ibuprofen, galaxolide, tributyl phosphate, 4-octylphenol, tris(2-chloroethyl) phosphate and carbamazepine for 10 incubation days. Non-aerated and darkness reactors were used as controls. Microalgae grew at a rate of 0.25 d{sup −1} with the complete removal of N-NH{sub 4} during the course of the experiment. After 10 incubation days, up to 99% of the microcontaminants with a Henry’s law constant higher than 3 10{sup −1} Pa m{sup 3} mol{sup −1} (i.e., 4-octylphenol, galaxolide, and tributyl phosphate) were removed by volatilization due to the effect of air stripping. Whereas biodegradation was effective for removing ibuprofen and caffeine, carbamazepine and tris(2-chloroethyl) phosphate behaved as recalcitrant compounds. The use of microalgae was proved to be relevant for increasing the biodegradation removal efficiency of ibuprofen by 40% and reducing the lag phase of caffeine by 3 days. Moreover, the enantioselective biodegradation of S-ibuprofen suggested a biotic prevalent removal process, which was supported by the identification of carboxy-ibuprofen and hydroxy-ibuprofen. The results from microalgae reactors fed with synthetic wastewater showed no clear evidences of microalgae uptake of any of the studied microcontaminants.

  15. Flashing light in microalgae biotechnology.

    Science.gov (United States)

    Abu-Ghosh, Said; Fixler, Dror; Dubinsky, Zvy; Iluz, David

    2016-03-01

    Flashing light can enhance photosynthesis and improve the quality and quantity of microalgal biomass, as it can increase the products of interest by magnitudes. Therefore, the integration of flashing light effect into microalgal cultivation systems should be considered. However, microalgae require a balanced mix of the light/dark cycle for higher growth rates, and respond to light intensity differently according to the pigments acquired or lost during the growth. This review highlights recently published results on flashing light effect on microalgae and its applications in biotechnology, as well as the recently developed bioreactors designed to fulfill this effect. It also discusses how this knowledge can be applied in selecting the optimal light frequencies and intensities with specific technical properties for increasing biomass production and/or the yield of the chemicals of interest by microalgae belonging to different genera. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Heavy metal sorption by microalgae

    International Nuclear Information System (INIS)

    Sandau, E.; Sandau, P.; Pulz, O.

    1996-01-01

    Viable microalgae are known to be able to accumulate heavy metals (bioaccumulation). Against a background of the increasing environmental risks caused by heavy metals, the microalgae Chlorella vulgaris and Spirulina platensis and their potential for the biological removal of heavy metals from aqueous solutions were taken as an example for investigation. Small-scale cultivation tests (50 l) with Cd-resistant cells of Chlorella vulgaris have shown that approx. 40% of the added 10 mg Cd/l was removed from the solution within seven days. At this heavy metal concentration sensitive cells died. Non-viable microalgae are able to eliminate heavy metal ions in a short time by biosorption in uncomplicated systems, without any toxicity problems. Compared with original biomasses, the sorption capacity of microalgal by-products changes only insignificantly. Their low price makes them economical. (orig.)

  17. Phosphopantetheinylation in the green microalgae Chlamydomonas reinhardtii

    DEFF Research Database (Denmark)

    Sonnenschein, Eva; Pu, Yuan; Beld, Joris

    2016-01-01

    available microalgal genome data revealed that most green microalgae appear to carry two PPTases forming clusters with each C. reinhardtii PPTase, while microalgae of other divisions carry one or two PPTases and do not cluster in the pattern of the green algal data. This new understanding on the PPTases...... in microalgae shows that microalgae are already primed for biotechnological applications in contrast to other organisms. Thus, microalgae have great potential for metabolic engineering efforts in the realm of biofuel and high-value products including direct engineering of the fatty acid or secondary metabolism...

  18. Airborne Microalgae: Insights, Opportunities, and Challenges

    Science.gov (United States)

    Skjøth, Carsten Ambelas; Šantl-Temkiv, Tina; Löndahl, Jakob

    2016-01-01

    Airborne dispersal of microalgae has largely been a blind spot in environmental biological studies because of their low concentration in the atmosphere and the technical limitations in investigating microalgae from air samples. Recent studies show that airborne microalgae can survive air transportation and interact with the environment, possibly influencing their deposition rates. This minireview presents a summary of these studies and traces the possible route, step by step, from established ecosystems to new habitats through air transportation over a variety of geographic scales. Emission, transportation, deposition, and adaptation to atmospheric stress are discussed, as well as the consequences of their dispersal on health and the environment and state-of-the-art techniques to detect and model airborne microalga dispersal. More-detailed studies on the microalga atmospheric cycle, including, for instance, ice nucleation activity and transport simulations, are crucial for improving our understanding of microalga ecology, identifying microalga interactions with the environment, and preventing unwanted contamination events or invasions. PMID:26801574

  19. Evaluation of the potential for some isolated microalgae to produce biodiesel

    Directory of Open Access Journals (Sweden)

    Eman A. Mahmoud

    2015-03-01

    Full Text Available The energy and the world food crises have ignited interest in algal culture for making biodiesel, bioethanol, biobutanol and other biofuels using the land that is not suitable for agriculture. Algal fuel is an alternative to fossil fuel that uses algae as its source of natural deposits. Microalgal lipids are the oils of the future for sustainable biodiesel production. One of the most important roles in obtaining oil from microalgae is the choice of species. A total of fifteen microalgal isolates, obtained from brackish and fresh waters, were assayed at the laboratory for their ability to high biomass productivity and lipid content. Only three microalgae were selected as the most potent isolates for biomass and lipid production. They have been identified as Chlorella vulgaris, Scenedesmus quadri and Trachelomonas oblonga. All of them were cultivated on BG11 media and harvested by centrifugation. The dry weight of the three isolates was recorded as 1.23, 1.09 and 0.9 g/l while the lipid contents were 37%, 34% and 29%, respectively which can be considered a promising biomass production and lipid content.

  20. Effect of media composition and light supply on biomass, lipid content and FAME profile for quality biofuel production from Scenedesmus abundans

    International Nuclear Information System (INIS)

    Rai, Monika Prakash; Gupta, Shivani

    2017-01-01

    Highlights: • S. abundans lipids have the potential to produce high quality biodiesel. • Maximum growth and lipid production were observed in Fogg’s medium without nitrogen. • Light intensity and photoperiod are found influential parameters for high lipid accumulation (48.12%). • FAME profile shows elevated levels of C16:0, C8:1 and C18:2 (biodiesel precursors) under optimized culture conditions. • S. abundans biodiesel properties meets international biodiesel standards. - Abstract: Microalgae have a potential to serve as a renewable feedstock for synthesis of biodiesel, rich in saturated and unsaturated fatty acids and valuable biomolecules. Role of several parameters such as nutrient composition, light intensity, photoperiod and pH on growth and lipid productivity was investigated. A freshwater green microalga Scenedesmus abundans was selected as a potential candidate for production of biodiesel and its growth conditions were optimized for enhanced lipid accumulation. The lipid content of the strain has been increased up to about 48% when grown in modified Fogg’s medium at pH 8 with light intensity of 40.5 μmol m"−"2 s"−"1 and photoperiod of 16 h light:8 h dark. Lipids were transesterified and the fatty acid methyl esters (FAME) thus obtained were analyzed by GC–MS. They possess more than 80% of C_1_6 to C_1_8 fatty acids, which are major precursors for biodiesel production. The FAME consisted of saturated (47.83%), monounsaturated (26.38%) and polyunsaturated (25.20%) fatty acids. Several important biodiesel quality parameters were predicted and compared to the corresponding specifications in the American and European biodiesel standards. The study opens up new vistas for utilization of the microalga, S. abundans for efficient production of biodiesel.

  1. Effect of chemicals on production, composition and antioxidant activity of polysaccharides of Inonotus obliquus.

    Science.gov (United States)

    Xu, Xiangqun; Quan, Lili; Shen, Mengwei

    2015-01-01

    Polysaccharides are important secondary metabolites from the medicinal mushroom Inonotus obliquus. Various fatty acids, surfactants and organic solvents as cell membrane-reorganizing chemicals were investigated for their stimulatory effects on the growth of fungal mycelium and production of exopolysaccharides (EPS) and endopolysaccharides (IPS) by submerged fermentation of I. obliquus. After evaluation of 14 chemicals, oleic acid, Tween 80, and TritonX-100 were chosen for optimization of addition concentration and addition time. Among the three chemicals, 0.1% (v/v) Tween 80 gave maximum production of mycelial biomass, EPS, IPS1, and IPS2 with a increase of 16.6, 81.6, 37.7 and 18.1%, respectively, when supplemented at the early growth phase (24h after inoculation). These EPS, IPS1, and IPS2 had significantly (pmonosaccharide compositions than those from the control. The simultaneously enhanced accumulation of bioactive EPS and IPS of cultured I. obliquus supplemented with Tween 80 was evident. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Plastocyanin/cytochrome c6 interchange in Scenedesmus vacuolatus.

    Science.gov (United States)

    Miramar, M Dolores; Inda, Luis A; Saraiva, Lígia M; Peleato, M Luisa

    2003-12-01

    Plastocyanin and cytochrome c6 from the green alga Scenedesmus vacuolatus were immunoquantified in cells grown under different concentrations of copper and iron. Plastocyanin expression was constitutive, its synthesis was not significantly affected by iron availability, and increases with copper availability. On the contrary, cytochrome c6 synthesis is repressed by copper, and only residual amounts of the protein were detected at 0.1 micromol/L copper. Under copper deficiency, cytochrome c6 is slightly dependent on iron. In natural environments, plastocyanin seems to be the predominant electron donor to P700.

  3. Cell disruption for microalgae biorefineries

    NARCIS (Netherlands)

    Günerken, E.; Hondt, d' E.; Eppink, M.H.M.; Garcia-Gonzalez, L.; Elst, K.; Wijffels, R.H.

    2015-01-01

    Microalgae are a potential source for various valuable chemicals for commercial applications ranging from nutraceuticals to fuels. Objective in a biorefinery is to utilize biomass ingredients efficiently similarly to petroleum refineries in which oil is fractionated in fuels and a variety of

  4. 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.

  5. Efficient recovery of uranium using genetically improved microalgae; Recuperacion eficaz de uranio utilizando microalgas geneticamente mejoradas

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Rodas, V.; Gonzalez Conde, E.; Garcia-Balboa, C.

    2014-07-01

    Although bioaccumulation is an enzymatic process that requires live microalgae bio sorption is based on physicochemical interactions, and it is not necessary that microalgae are alive, whereby dried microalgae biomass achieves the same results. This alternative could represent a new safe and inexpensive way to recover U. (Author)

  6. 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 m 2 ). 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 g CDW  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 g CDW  L -1 was reached. Afterward, the biomass concentration remained constant

  7. Microalgae removal with Moringa oleifera.

    Science.gov (United States)

    Barrado-Moreno, M M; Beltran-Heredia, J; Martín-Gallardo, J

    2016-02-01

    Moringa oleifera seed extract was tested for algae (Chlorella, Microcystis, Oocystis and Scenedesmus) removal by Jar-test technique. This coagulant can be used in drinking water treatment. Jar-test has been carried out in order to evaluate the efficiency of this natural coagulant agent inside real surface water matrix. The influence of variables has been studied in this process, including operating parameters such as coagulant dosage, initial algae concentration, pH, agitation time and water matrix. Removal capacity is verified for water with high contamination of algae while the process is not affected by the pH and water matrix. Coagulation process may be modelling through Langmuir and Freundlich adsorption hypothesis, so acceptable r2 coefficients are obtained. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Microalgae Culture Collection: 1984-1985

    Energy Technology Data Exchange (ETDEWEB)

    1984-09-01

    The Microalgae Culture Collection at the Solar Energy Research Institute has been established for the maintenance and distribution of strains that have been characterized for biomass fuel applications.

  9. Microalgae as embedded environmental monitors

    International Nuclear Information System (INIS)

    Ogburn, Zachary L.; Vogt, Frank

    2017-01-01

    In marine ecosystems, microalgae are an important component as they transform large quantities of inorganic compounds into biomass and thereby impact environmental chemistry. Of particular relevance is phytoplankton's sequestration of atmospheric CO 2 , a greenhouse gas, and nitrate, one cause of harmful algae blooms. On the other hand, microalgae sensitively respond to changes in their chemical environment, which initiates an adaptation of their chemical composition. Analytical methodologies were developed in this study that utilize microalgae's adaptation as a novel approach for in-situ environmental monitoring. Longterm applications of these novel methods are investigations of environmental impacts on phytoplankton's sequestration performance and their nutritional value to higher organisms feeding on them. In order to analyze the chemical composition of live microalgae cells (Nannochloropsis oculata), FTIR-ATR spectroscopy has been employed. From time series of IR spectra, the formation of bio-sediment can be monitored and it has been shown that the nutrient availability has a small but observable impact. Since this bio-sediment formation is governed by several biological parameters of the cells such as growth rate, size, buoyancy, number of cells, etc., this enables studies of chemical environment's impact on biomass formation and the cells' physical parameters. Moreover, the spectroscopic signature of these microalgae has been determined from cultures grown under 25 different CO 2 and NO 3 − mixtures (200 ppm-600 ppm CO 2 , 0.35 mM-0.75 mM NO 3 − ). A novel, nonlinear modeling methodology coined ‘Predictor Surfaces’ is being presented by means of which the nonlinear responses of the cells to their chemical environment could reliably be described. This approach has been utilized to measure the CO 2 concentration in the atmosphere over the phytoplankton culture as well as the nitrate concentration dissolved in their growing

  10. Microalgae as embedded environmental monitors

    Energy Technology Data Exchange (ETDEWEB)

    Ogburn, Zachary L.; Vogt, Frank, E-mail: fvogt@utk.edu

    2017-02-15

    In marine ecosystems, microalgae are an important component as they transform large quantities of inorganic compounds into biomass and thereby impact environmental chemistry. Of particular relevance is phytoplankton's sequestration of atmospheric CO{sub 2}, a greenhouse gas, and nitrate, one cause of harmful algae blooms. On the other hand, microalgae sensitively respond to changes in their chemical environment, which initiates an adaptation of their chemical composition. Analytical methodologies were developed in this study that utilize microalgae's adaptation as a novel approach for in-situ environmental monitoring. Longterm applications of these novel methods are investigations of environmental impacts on phytoplankton's sequestration performance and their nutritional value to higher organisms feeding on them. In order to analyze the chemical composition of live microalgae cells (Nannochloropsis oculata), FTIR-ATR spectroscopy has been employed. From time series of IR spectra, the formation of bio-sediment can be monitored and it has been shown that the nutrient availability has a small but observable impact. Since this bio-sediment formation is governed by several biological parameters of the cells such as growth rate, size, buoyancy, number of cells, etc., this enables studies of chemical environment's impact on biomass formation and the cells' physical parameters. Moreover, the spectroscopic signature of these microalgae has been determined from cultures grown under 25 different CO{sub 2} and NO{sub 3}{sup −} mixtures (200 ppm-600 ppm CO{sub 2}, 0.35 mM-0.75 mM NO{sub 3}{sup −}). A novel, nonlinear modeling methodology coined ‘Predictor Surfaces’ is being presented by means of which the nonlinear responses of the cells to their chemical environment could reliably be described. This approach has been utilized to measure the CO{sub 2} concentration in the atmosphere over the phytoplankton culture as well as the nitrate

  11. Biodiesel from microalgae beats bioethanol.

    Science.gov (United States)

    Chisti, Yusuf

    2008-03-01

    Renewable biofuels are needed to displace petroleum-derived transport fuels, which contribute to global warming and are of limited availability. Biodiesel and bioethanol are the two potential renewable fuels that have attracted the most attention. As demonstrated here, biodiesel and bioethanol produced from agricultural crops using existing methods cannot sustainably replace fossil-based transport fuels, but there is an alternative. Biodiesel from microalgae seems to be the only renewable biofuel that has the potential to completely displace petroleum-derived transport fuels without adversely affecting supply of food and other crop products. Most productive oil crops, such as oil palm, do not come close to microalgae in being able to sustainably provide the necessary amounts of biodiesel. Similarly, bioethanol from sugarcane is no match for microalgal biodiesel.

  12. 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.

  13. Discovery of Bioactive Metabolites in Biofuel Microalgae That Offer Protection against Predatory Bacteria

    Directory of Open Access Journals (Sweden)

    Christopher eBagwell

    2016-04-01

    Full Text Available Microalgae could become an important resource for addressing increasing global demand for food, energy, and commodities while helping to reduce atmospheric greenhouse gases. Even though Chlorophytes are generally regarded safe for human consumption, there is still much we do not understand about the metabolic and biochemical potential of microscopic algae. The aim of this study was to evaluate biofuel candidate strains of Chlorella and Scenedesmus for the potential to produce bioactive metabolites when grown under nutrient depletion regimes intended to stimulate production of triacylglycerides (TAG. Strain specific combinations of macro- and micro-nutrient restricted growth media did stimulate neutral lipid accumulation by microalgal cultures. However, cultures that were restricted for iron consistently and reliably tested positive for cytotoxicity by in vivo bioassays. The addition of iron back to these cultures resulted in the disappearance of the bioactive components by LC/MS fingerprinting and loss of cytotoxicity by in vivo bioassay. Incomplete NMR characterization of the most abundant cytotoxic fractions suggested that small molecular weight peptides and glycosides could be responsible for Chlorella cytotoxicity. Experiments were conducted to determine if the bioactive metabolites induced by Fe-limitation in Chlorella sp. cultures would elicit protection against Vampirovibrio chlorellavorus, an obligate predator of Chlorella. Introduction of V. chlorellavorus resulted in a 72% decrease in algal biomass in the experimental controls after 7 days. Conversely, only slight losses of algal biomass were measured for the iron limited Chlorella cultures (0 - 9 %. This study demonstrates a causal linkage between iron bioavailability and bioactive metabolite production in strains of Chlorella and Scenedesmus. Further study of this phenomenon could contribute to the development of new strategies to extend algal production cycles in open, outdoor

  14. Metal bioaccumulation by the freshwater alga Scenedesmus quadricauda

    International Nuclear Information System (INIS)

    Fargasova, A.

    1997-01-01

    Bioaccumulation of six metals (Cu 2+ , Cu + , Mo 6+ , Mn 2+ , V 5+ , Ni 2+ ) and their combinations by alga Scenedesmus quadricauda was determined by using radio nuclide X-ray fluorescence (RXFA). The metals were added into the cultivation medium in concentrations corresponding with EC 50 value for each metal. The obtained results indicate that Ni 2+ , Cu 2+ and Cu + were accumulated in high amounts (20%, 17.5% and 15.9%) the Mo 6+ ion ( 2+ , Ni, Mn, V; V→Ni, Mn; Mn→Ni, Cu 2+ , Cu + ; Cu + →Ni; Cu 2+ →Ni; Ni→Mn, V), enhancement (V→Cu + ; Cu 2+ →Mn; Cu + →V, Mn; Mn→V; Ni→Cu 2+ , Cu + ) and neutral effect (V→Mo; Cu 2+ →Mo; Cu + →Mo; Mn→Mo; Ni→Mo). (author)

  15. Microalgae production in a biofilm photobioreactor

    NARCIS (Netherlands)

    Blanken, Ward

    2016-01-01

    Microalgae can be used to produce high-value compounds, such as pigments or high value fatty acids, or as a feedstock for lower value products such as food and feed compounds, biochemicals, and biofuels. In order to produce these bulk products competitively, it is required to lower microalgae

  16. Production of biofuels obtained from microalgae

    Directory of Open Access Journals (Sweden)

    Luis Carlos Fernández-Linares

    2012-09-01

    Full Text Available A review of the situation of bio-fuels in the world, mainly of biodiesel is made. A comparison among the different raw materials for the synthesis of biodiesel is done and it is emphasized in the production of biodiesel from microalgae. The different fresh and salt water micro-algae in its lipid content and productivity are compared. A review of the process of biosynthesis of lipids in microalgae and how to improve the production of lipids in microalgae is shown. It is discussed the importance of the genetic manipulation to highly lipid-producing microalgae (example: Botryrococuus braunni, Nannochloropsis sp, Noechlorisoleobundans and Nitschia sp.. A study of the advantages and disadvantages of the different systems of cultivation of microalgae is also made. Finally, it is shown a perspective of biofuels from microalgae. Among the main challenges to overcome to produce biodiesel from microalgae are: the cost of production of biomass, which involves the optimization of media, selection and manipulation of strains and photobioreactors design. The processof separation of biomass, the extraction of oils and by-products, the optimization of the process of transesterification, purification and use of by-products must also be considered.

  17. Harvesting and cell disruption of microalgae

    NARCIS (Netherlands)

    Lam, 't Gerard Pieter

    2017-01-01

    Microalgae are a potential feedstock for various products. At the moment, they are already used as feedstock for high-valuable products (e.g. aquaculture and pigments).

    Microalgae pre-dominantly consist out of proteins, lipids and carbohydrates. This makes algae an interesting feedstock

  18. Microalgae for biofuels production and environmental applications ...

    African Journals Online (AJOL)

    This review presents the current classification of biofuels, with special focus on microalgae and their applicability for the production of biodiesel. The paper considered issues related with the processing and culturing of microalgae, for not only those that are involved in biofuel production, but as well as the possibility of their ...

  19. Highly valuable microalgae: biochemical and topological aspects.

    Science.gov (United States)

    Pignolet, Olivier; Jubeau, Sébastien; Vaca-Garcia, Carlos; Michaud, Philippe

    2013-08-01

    The past decade has seen a surge in the interest in microalgae culture for biodiesel production and other applications as renewable biofuels as an alternative to petroleum transport fuels. The development of new technologies for the culture of these photosynthetic microorganisms and improved knowledge of their biochemical composition has spurred innovation in the field of high-value biomolecules. These developments are only economically viable if all the microalgae fractions are valorized in a biorefinery strategy. Achieving this objective requires an understanding of microalgae content and the cellular localization of the main biomolecular families in order to develop efficient harvest and sequential recovery technologies. This review summarizes the state of the art in microalgae compositions and topologies using some examples of the main industrially farmed microalgae.

  20. Application of semipermeable membrane device (SPMD) for assessment of organic toxicants dangerous to the green microalga Scenedesmus subspicatus

    Czech Academy of Sciences Publication Activity Database

    Kočí, V.; Lukavský, Jaromír; Mlejnek, M.; Kochánková, L.; Grabic, R.; Ocelka, T.

    2004-01-01

    Roč. 150, č. 111 (2004), s. 173-186 ISSN 0342-1120 R&D Projects: GA AV ČR KSK6005114; GA ČR GA203/00/D014 Institutional research plan: CEZ:AV0Z6005908 Keywords : bioassay * passive sampling * Daphnia magna Subject RIV: EF - Botanics

  1. Development and testing of a recorder and controller for a microalgae culture reactor; Desarrollo y prueba de un registrador y controlador para un reactor de cultivo de microalgas

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, Wilson; Reyes, Jose Fernando; Bruijn, Johannes; Hernandez, Alejandro [Universidad de Concepcion, Chilan (Chile). Facultad de Ingenieria Agricola. Dept. de Mecanizacion y Energia], Emails: wesquive@udec.cl., jreyes@udec.cl., jdebruij@udec.cl., alehernandez@udec.cl

    2010-07-01

    An electronic system to monitor and control operational variables in a Raceway type of reactor for the culture of the Scenedesmus spinosus microalgae and later production for biodiesel and mitigating CO{sub 2} was developed and tested. The electronic system is constituted by a micro controller, a card reader SD, a card SD, a real-time clock, a power supply, a screen GLCD, a keyboard and a card for data acquisition, all implemented for 4-20 mA and 0-5 V output sensors. Temperature, pH, electrical conductivity, dissolved oxygen and solar radiation were measured digitalized and saved every 10 minutes. These variables were digitalized and kept in the SD memory every 10 minutes. It was determined that the most favorable conditions for the proliferation of the culture are near pH neutral and a temperature of 30 deg C, existing a strong correlation between pH and the dissolved CO{sub 2} level. Using the digital outputs of temperature and pH of the microcontroller, the CO{sub 2} injection and the elimination of O{sub 2} were controlled to maintain an adequate environment for the development of the culture. (author)

  2. 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

  3. An evidence of C16 fatty acid methyl esters extracted from microalga for effective antimicrobial and antioxidant property.

    Science.gov (United States)

    Davoodbasha, MubarakAli; Edachery, Baldev; Nooruddin, Thajuddin; Lee, Sang-Yul; Kim, Jung-Wan

    2018-02-01

    Fatty acid methyl esters (FAME) derived from lipids of microalgae is known to have wide bio-functional materials including antimicrobials. FAME is an ideal super-curator and superior anti-pathogenic. The present study evaluated the efficiency of FAME extracted from microalgae Scenedesmus intermedius as an antimicrobial agent against Gram positive (Staphylococcus aureus, Streptococcus mutans, and Bacillus cereus) Gram negative (Escherichia coli and Pseudomonas aeruginosa) bacteria and Fungi (Aspergillus parasiticus and Candida albicans). The minimal inhibitory concentration (MIC) for the gram negative bacteria was determined as 12-24 μg mL -1 , whereas MIC for gram positive bacteria was 24-48 μg mL -1 . MIC for the fungi was as high as 60-192 μg mL -1 . The FAME profiles determined by gas chromatography showed 18 methyl esters. Among them, pharmacologically active FAME such as palmitic acid methyl ester (C16:0) was detected at high percentage (23.08%), which accounted for the bioactivity. FAME obtained in this study exhibited a strong antimicrobial activity at the lowest MIC than those of recent reports. This result clearly indicated that FAME of S. intermedius has a strong antimicrobial and antioxidant property and that could be used as an effective resource against microbial diseases. Copyright © 2017. Published by Elsevier Ltd.

  4. 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

  5. Magnetically modified microalgae and their applications

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Procházková, G.; Pospíšková, K.; Brányik, T.

    2016-01-01

    Roč. 36, č. 5 (2016), s. 931-941 ISSN 0738-8551 R&D Projects: GA ČR GA13-13709S; GA MŠk(CZ) LD13021 Institutional support: RVO:67179843 Keywords : oleaginous chlorella sp * fresh-water microalgae * magnetophoretic separation * high-gradient * harvesting microalgae * alexandrium-fundyense * polymer binder * algal blooms * cells * removal * Harvesting algal cells * magnetic labeling * magnetic modification * magnetic separation * microalgae Subject RIV: EI - Biotechnology ; Bionics Impact factor: 6.542, year: 2016

  6. 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

  7. 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.

  8. Estimating the capability of microalgae to physiological acclimatization and genetic adaptation to petroleum and diesel oil contamination

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Lopez, Julia; Lopez-Rodas, Victoria [Genetica, Facultad de Veterinaria, Universidad Complutense de Madrid, Avda. Puerta de Hierro s/n, E-28040 Madrid (Spain); Costas, Eduardo, E-mail: ecostas@vet.ucm.es [Genetica, Facultad de Veterinaria, Universidad Complutense de Madrid, Avda. Puerta de Hierro s/n, E-28040 Madrid (Spain)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Microalgae are able to physiological acclimatization low doses of petroleum and diesel oil. Black-Right-Pointing-Pointer When petroleum or oil concentration exceeds these limits, survival depend of rare mutations. Black-Right-Pointing-Pointer Petroleum-resistant and diesel oil mutants occur spontaneously prior to oil exposure. Black-Right-Pointing-Pointer After 300 generations of artificial selection resistant strains were obtained. Black-Right-Pointing-Pointer Cyanobacteria has more difficulties to achieve petroleum resistance than Chlorophyta. - Abstract: There is increasing scientific interest in how phytoplankton reacts to petroleum contamination, since crude oil and its derivatives are generating extensive contamination of aquatic environments. However, toxic effects of short-term petroleum exposure are more widely known than the adaptation of phytoplankton to long-term petroleum exposure. An analysis of short-term and long-term effects of petroleum exposure was done using experimental populations of freshwater (Scenedesmus intermedius and Microcystis aeruginosa) and marine (Dunaliella tertiolecta) microalgae isolated from pristine sites without crude oil product contamination. These strains were exposed to increased levels of petroleum and diesel oil. Short-term exposure to petroleum or diesel oil revealed a rapid inhibition of photosynthetic performance and cell proliferation in freshwater and marine phytoplankton species. A broad degree of inter-specific variation in lethal contamination level was observed. When different strains were exposed to petroleum or diesel oil over the long-term, the cultures showed massive destruction of the sensitive cells. Nonetheless, after further incubation, some cultures were able to grow again due to cells that were resistant to the toxins. By means of a fluctuation analysis, discrimination between cells that had become resistant due to physiological acclimatization and resistant

  9. Estimating the capability of microalgae to physiological acclimatization and genetic adaptation to petroleum and diesel oil contamination

    International Nuclear Information System (INIS)

    Romero-Lopez, Julia; Lopez-Rodas, Victoria; Costas, Eduardo

    2012-01-01

    Highlights: ► Microalgae are able to physiological acclimatization low doses of petroleum and diesel oil. ► When petroleum or oil concentration exceeds these limits, survival depend of rare mutations. ► Petroleum-resistant and diesel oil mutants occur spontaneously prior to oil exposure. ► After 300 generations of artificial selection resistant strains were obtained. ► Cyanobacteria has more difficulties to achieve petroleum resistance than Chlorophyta. - Abstract: There is increasing scientific interest in how phytoplankton reacts to petroleum contamination, since crude oil and its derivatives are generating extensive contamination of aquatic environments. However, toxic effects of short-term petroleum exposure are more widely known than the adaptation of phytoplankton to long-term petroleum exposure. An analysis of short-term and long-term effects of petroleum exposure was done using experimental populations of freshwater (Scenedesmus intermedius and Microcystis aeruginosa) and marine (Dunaliella tertiolecta) microalgae isolated from pristine sites without crude oil product contamination. These strains were exposed to increased levels of petroleum and diesel oil. Short-term exposure to petroleum or diesel oil revealed a rapid inhibition of photosynthetic performance and cell proliferation in freshwater and marine phytoplankton species. A broad degree of inter-specific variation in lethal contamination level was observed. When different strains were exposed to petroleum or diesel oil over the long-term, the cultures showed massive destruction of the sensitive cells. Nonetheless, after further incubation, some cultures were able to grow again due to cells that were resistant to the toxins. By means of a fluctuation analysis, discrimination between cells that had become resistant due to physiological acclimatization and resistant cells arising from rare spontaneous mutations was accomplished. In addition, an analysis was done as to the maximum capacity of

  10. 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.

  11. Modeling and visual simulation of Microalgae photobioreactor

    Science.gov (United States)

    Zhao, Ming; Hou, Dapeng; Hu, Dawei

    Microalgae is a kind of nutritious and high photosynthetic efficiency autotrophic plant, which is widely distributed in the land and the sea. It can be extensively used in medicine, food, aerospace, biotechnology, environmental protection and other fields. Photobioreactor which is important equipment is mainly used to cultivate massive and high-density microalgae. In this paper, based on the mathematical model of microalgae which grew under different light intensity, three-dimensional visualization model was built and implemented in 3ds max, Virtools and some other three dimensional software. Microalgae is photosynthetic organism, it can efficiently produce oxygen and absorb carbon dioxide. The goal of the visual simulation is to display its change and impacting on oxygen and carbon dioxide intuitively. In this paper, different temperatures and light intensities were selected to control the photobioreactor, and dynamic change of microalgal biomass, Oxygen and carbon dioxide was observed with the aim of providing visualization support for microalgal and photobioreactor research.

  12. Biologically Active Metabolites Synthesized by Microalgae

    Directory of Open Access Journals (Sweden)

    Michele Greque de Morais

    2015-01-01

    Full Text Available Microalgae are microorganisms that have different morphological, physiological, and genetic traits that confer the ability to produce different biologically active metabolites. Microalgal biotechnology has become a subject of study for various fields, due to the varied bioproducts that can be obtained from these microorganisms. When microalgal cultivation processes are better understood, microalgae can become an environmentally friendly and economically viable source of compounds of interest, because production can be optimized in a controlled culture. The bioactive compounds derived from microalgae have anti-inflammatory, antimicrobial, and antioxidant activities, among others. Furthermore, these microorganisms have the ability to promote health and reduce the risk of the development of degenerative diseases. In this context, the aim of this review is to discuss bioactive metabolites produced by microalgae for possible applications in the life sciences.

  13. The effects of gamma radiation on scenedesmus quaricauda (Turp.) Breb

    International Nuclear Information System (INIS)

    Aranez, A.T.; Antonio, B.A.

    1983-01-01

    Scenedesmus quadricauda (Turp) Breb. were exposed to 0.5 kr, 3 kr, 6 kr, 9 kr, and 12 kr of gamma radiation. The low dose of 0.5 increased the growth rate of 3.12% during the first week and by 15.27% and 20.48% during the third and fourth weeks respectively. The stimulating effect was observed up to the fourth week only. The growth rate of the algae treated with 3 kr and that of the control were almost the same. Those treated with 6 kr, 9 kr and 12 kr gamma rays had growth rates of 86.33%, 70.70%, and 58.20% of control respectively during the first week after which their growth rates surpassed that of the control. Mutant cells twice the size of the normal ones, occurred as single cells, in coenobia of 2 cells, or in coenobia of 4 cells. These mutants have been successfully propagated. Coenobia with enlarged cells, with cells of abnormal shape, with cells of unequal sizes, and with unusual arrangement of cells were noted. There were also coenobia containing cells with kidney-shaped chloroplast. (Auth.)

  14. From tiny microalgae to huge biorefineries

    OpenAIRE

    Gouveia, L.

    2014-01-01

    Microalgae are an emerging research field due to their high potential as a source of several biofuels in addition to the fact that they have a high-nutritional value and contain compounds that have health benefits. They are also highly used for water stream bioremediation and carbon dioxide mitigation. Therefore, the tiny microalgae could lead to a huge source of compounds and products, giving a good example of a real biorefinery approach. This work shows and presents examples of experimental...

  15. Comparison between direct transesterification of microalgae and hydrochar

    Directory of Open Access Journals (Sweden)

    Vo Thanh Phuoc

    2017-07-01

    Full Text Available Hydrothermal carbonization (HTC of microalgae is one of processes that can effectively remove moisture from microalgae. In addition, the hydrochar retains most of fatty acids from microalgae feedstock, and the content of fatty acids in hydrochar is doubled. This research concentrates on the comparison between direct transesterification of microalgae and hydrochar. The result shows that the biodiesel yields of hydrochar were higher than those of microalgae at the same reaction conditions due to the higher extraction rate of fatty acids from hydrochar. Finally, the amount of methanol and catalyst which is required for a given amount of microalgae can be reduced to a half through the direct transesterification of hydrochar.

  16. Marine Microalgae with Anti-Cancer Properties.

    Science.gov (United States)

    Martínez Andrade, Kevin A; Lauritano, Chiara; Romano, Giovanna; Ianora, Adrianna

    2018-05-15

    Cancer is the leading cause of death globally and finding new therapeutic agents for cancer treatment remains a major challenge in the pursuit for a cure. This paper presents an overview on microalgae with anti-cancer activities. Microalgae are eukaryotic unicellular plants that contribute up to 40% of global primary productivity. They are excellent sources of pigments, lipids, carotenoids, omega-3 fatty acids, polysaccharides, vitamins and other fine chemicals, and there is an increasing demand for their use as nutraceuticals and food supplements. Some microalgae are also reported as having anti-cancer activity. In this review, we report the microalgal species that have shown anti-cancer properties, the cancer cell lines affected by algae and the concentrations of compounds/extracts tested to induce arrest of cell growth. We also report the mediums used for growing microalgae that showed anti-cancer activity and compare the bioactivity of these microalgae with marine anticancer drugs already on the market and in phase III clinical trials. Finally, we discuss why some microalgae can be promising sources of anti-cancer compounds for future development.

  17. Bioremediation of wastewater using microalgae

    Science.gov (United States)

    Chalivendra, Saikumar

    Population expansion and industrial development has deteriorated the quality of freshwater reservoirs around the world and has caused freshwater shortages in certain areas. Discharge of industrial effluents containing toxic heavy metals such as Cd and Cr into the environment have serious impact on human, animal and aquatic life. In order to solve these problems, the present study was focused on evaluating and demonstrating potential of microalgae for bioremediation of wastewater laden with nitrogen (N) in the form of nitrates, phosphorous (P) in the form of phosphates, chromium (Cr (VI)) and cadmium (Cd (II)). After screening several microalgae, Chlorella vulgaris and algae taken from Pleasant Hill Lake were chosen as candidate species for this study. The viability of the process was demonstrated in laboratory bioreactors and various experimental parameters such as contact time, initial metal concentration, algae concentration, pH and temperature that would affect remediation rates were studied. Based on the experimental results, correlations were developed to enable customizing and designing a commercial Algae based Wastewater Treatment System (AWTS). A commercial AWTS system that can be easily customized and is suitable for integration into existing wastewater treatment facilities was developed, and capital cost estimates for system including installation and annual operating costs were determined. The work concludes that algal bioremediation is a viable alternate technology for treating wastewater in an economical and sustainable way when compared to conventional treatment processes. The annual wastewater treatment cost to remove N,P is ~26x lower and to remove Cr, Cd is 7x lower than conventional treatment processes. The cost benefit analysis performed shows that if this technology is implemented at industrial complexes, Air Force freight and other Department of Defense installations with wastewater treatment plants, it could lead to millions of dollars in

  18. Fungi & Health: can polysaccharides from the fungus inonotus obliquus (CHAGA) inhibit tumor growth?

    DEFF Research Database (Denmark)

    Wold, C. W.; Corthay, A.; Kjeldsen, Christian

    Inonotus obliquus (Chaga) – a white rot fungus found on birch trees in the northern hemisphere –has been used in traditional medicine in Europe and Asia for centuries. Native peoples have made use of Chaga by brewing it as a tea to treat gastro-intestinal problems, to heal wounds and even to treat...... 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...... the tumor inhibiting effect is two-fold: i) fungal polysaccharides may inhibit tumor growth indirectly by activating certain immune cells such as macrophages and ii) triterpenoids and other steroids from Chaga may give a direct cytotoxic effect against cancer cells. While triterpenoids from Chaga have been...

  19. Microalgae growth on the aqueous phase from Hydrothermal Liquefaction of the same microalgae

    NARCIS (Netherlands)

    Garcia Alba, Laura; Torri, Cristian; Fabbri, Daniele; Kersten, Sascha R.A.; Brilman, Derk Willem Frederik

    2013-01-01

    Cultivation of Desmodesmus sp. microalgae in the recycled aqueous phase (AP) recovered after Hydrothermal Liquefaction (HTL) of the same microalgae was studied to evaluate the potential of nutrients recycling. AP dilution ratio was systematically varied, using either water or water enriched with

  20. Effect of sequential isoproturon pulse exposure on Scenedesmus vacuolatus.

    Science.gov (United States)

    Vallotton, Nathalie; Eggen, Rik Ilda Lambertus; Chèvre, Nathalie

    2009-04-01

    Aquatic organisms are typically exposed to fluctuating concentrations of herbicides in streams. To assess the effects on algae of repeated peak exposure to the herbicide isoproturon, we subjected the alga Scenedesmus vacuolatus to two sequential pulse exposure scenarios. Effects on growth and on the inhibition of the effective quantum yield of photosystem II (PSII) were measured. In the first scenario, algae were exposed to short, 5-h pulses at high isoproturon concentrations (400 and 1000 microg/l), each followed by a recovery period of 18 h, while the second scenario consisted of 22.5-h pulses at lower concentrations (60 and 120 microg/l), alternating with short recovery periods (1.5 h). In addition, any changes in the sensitivity of the algae to isoproturon following sequential pulses were examined by determining the growth rate-EC(50) prior to and following exposure. In both exposure scenarios, we found that algal growth and its effective quantum yield were systematically inhibited during the exposures and that these effects were reversible. Sequential pulses to isoproturon could be considered a sequence of independent events. Nevertheless, a consequence of inhibited growth during the repeated exposures is the cumulative decrease in biomass production. Furthermore, in the second scenario, when the sequence of long pulses began to approach a scenario of continuous exposure, a slight increase in the tolerance of the algae to isoproturon was observed. These findings indicated that sequential pulses do affect algae during each pulse exposure, even if algae recover between the exposures. These observations could support an improved risk assessment of fluctuating exposures to reversibly acting herbicides.

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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.

  6. Elevated production of carotenoids by a new isolate of Scenedesmus sp

    Czech Academy of Sciences Publication Activity Database

    Přibyl, Pavel; Cepák, Vladislav; Kaštánek, P.; Zachleder, Vilém

    2015-01-01

    Roč. 11, č. 9 (2015), s. 22-27 ISSN 2211-9264 R&D Projects: GA TA ČR TE01020080; GA TA ČR TA03011027 Institutional support: RVO:67985939 ; RVO:61388971 Keywords : carotenoid * Scenedesmus * thin-layer photobioreactor Subject RIV: EI - Biotechnology ; Bionics; EE - Microbiology, Virology (MBU-M) Impact factor: 4.694, year: 2015

  7. Microalgae bulk growth model with application to industrial scale systems

    NARCIS (Netherlands)

    Quinn, J.; Winter, de L.; Bradley, T.

    2011-01-01

    The scalability of microalgae growth systems is a primary research topic in anticipation of the commercialization of microalgae-based biofuels. To date, there is little published data on the productivity of microalgae in growth systems that are scalable to commercially viable footprints. To inform

  8. Harvesting microalgae by bio-flocculation and autoflocculation

    NARCIS (Netherlands)

    Salim, S.

    2013-01-01

    Harvesting in commercial microalgae production plants is generally done by centrifugation, but this requires upto about 50% of the total energy gained from the microalgae. The energy needed for harvesting can be reduced considerably by pre-concentration of the microalgae prior to further dewatering.

  9. Cultivation of the microalga, Chlorella pyrenoidosa , in biogas ...

    African Journals Online (AJOL)

    Therefore, the microalga was introduced to be cultivated in the biogas wastewater, which could not only bioremediate the wastewater, but also produce plenty of the microalga biomass that could be used for the exploitation of fertilizers, feed additives and biofuels. This study showed that the microalga, C. pyrenoidosa could ...

  10. An Overview of Biocement Production from Microalgae

    Directory of Open Access Journals (Sweden)

    Dessy Ariyanti

    2011-12-01

    Full Text Available The invention of microorganism’s involvement in carbonate precipitation, has lead the exploration of this process in the field of construction engineering. Biocement is a product innovation from developing bioprocess technology called biocementation. Biocement refers to CaCO3 deposit that formed due to microorganism activity in the system rich of calcium ion. The primary role of microorganism in carbonate precipitation is mainly due to their ability to create an alkaline environment (high pH and DIC increase through their various physiological activities. Three main groups of microorganism that can induce the carbonate precipitation: (i photosynthetic microorganism such as cyanobacteria and microalgae; (ii sulphate reducing bacteria; and (iii some species of microorganism involved in nitrogen cycle. Microalgae are photosynthetic microorganism and utilize urea using urease or urea amidolyase enzyme, based on that it is possible to use microalgae as media to produce biocement through biocementation. This paper overviews biocement in general, biocementation, type of microorganism and their pathways in inducing carbonate precipitation and the prospect of microalgae to be used in biocement production.  Keywords— Biocement, Biocementation, Microalgae, CaCO3 precipitation

  11. Selenium Utilization Strategy by Microalgae

    Directory of Open Access Journals (Sweden)

    Hiroya Araie

    2009-11-01

    Full Text Available The diversity of selenoproteins raises the question of why so many life forms require selenium. Selenoproteins are found in bacteria, archaea, and many eukaryotes. In photosynthetic microorganisms, the essential requirement for selenium has been reported in 33 species belonging to six phyla, although its biochemical significance is still unclear. According to genome databases, 20 species are defined as selenoprotein-producing organisms, including five photosynthetic organisms. In a marine coccolithophorid, Emiliania huxleyi (Haptophyta, we recently found unique characteristics of selenium utilization and novel selenoproteins using 75Se-tracer experiments. In E. huxleyi, selenite, not selenate, is the main substrate used and its uptake is driven by an ATP-dependent highaffinity, active transport system. Selenite is immediately metabolized to low-molecular mass compounds and partly converted to at least six selenoproteins, named EhSEP1–6. The most (EhSEP2 and second-most abundant selenoproteins (EhSEP1 are disulfide isomerase (PDI homologous protein and thioredoxin reductase (TR 1, respectively. Involvement of selenium in PDI is unique in this organism, while TR1 is also found in other organisms. In this review, we summarize physiological, biochemical, and molecular aspects of selenium utilization by microalgae and discuss their strategy of selenium utilization.

  12. Can Microalgae Remove Pharmaceutical Contaminants from Water?

    Science.gov (United States)

    Xiong, Jiu-Qiang; Kurade, Mayur B; Jeon, Byong-Hun

    2018-01-01

    The increase in worldwide water contamination with numerous pharmaceutical contaminants (PCs) has become an emerging environmental concern due to their considerable ecotoxicities and associated health issues. Microalgae-mediated bioremediation of PCs has recently gained scientific attention, as microalgal bioremediation is a solar-power driven, ecologically comprehensive, and sustainable reclamation strategy. In this review, we comprehensively describe the current research on the possible roles and applications of microalgae for removing PCs from aqueous media. We summarize several novel approaches including constructing microbial consortia, acclimation, and cometabolism for enhanced removal of PCs by microalgae, which would improve practical feasibility of these technologies. Some novel concepts for degrading PCs using integrated processes and genetic modifications to realize algal-based bioremediation technologies are also recommended. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Mixotrophic cultivation of microalgae for biodiesel production: status and prospects.

    Science.gov (United States)

    Wang, Jinghan; Yang, Haizhen; Wang, Feng

    2014-04-01

    Biodiesel from microalgae provides a promising alternative for biofuel production. Microalgae can be produced under three major cultivation modes, namely photoautotrophic cultivation, heterotrophic cultivation, and mixotrophic cultivation. Potentials and practices of biodiesel production from microalgae have been demonstrated mostly focusing on photoautotrophic cultivation; mixotrophic cultivation of microalgae for biodiesel production has rarely been reviewed. This paper summarizes the mechanisms and virtues of mixotrophic microalgae cultivation through comparison with other major cultivation modes. Influencing factors of microalgal biodiesel production under mixotrophic cultivation are presented, development of combining microalgal biodiesel production with wastewater treatment is especially reviewed, and bottlenecks and strategies for future commercial production are also identified.

  14. Ecotoxicological effects of enrofloxacin and its removal by monoculture of microalgal species and their consortium.

    Science.gov (United States)

    Xiong, Jiu-Qiang; Kurade, Mayur B; Jeon, Byong-Hun

    2017-07-01

    Enrofloxacin (ENR), a fluoroquinolone antibiotic, has gained big scientific concern due to its ecotoxicity on aquatic microbiota. The ecotoxicity and removal of ENR by five individual microalgae species and their consortium were studied to correlate the behavior and interaction of ENR in natural systems. The individual microalgal species (Scenedesmus obliquus, Chlamydomonas mexicana, Chlorella vulgaris, Ourococcus multisporus, Micractinium resseri) and their consortium could withstand high doses of ENR (≤1 mg L -1 ). Growth inhibition (68-81%) of the individual microalgae species and their consortium was observed in ENR (100 mg L -1 ) compared to control after 11 days of cultivation. The calculated 96 h EC 50 of ENR for individual microalgae species and microalgae consortium was 9.6-15.0 mg ENR L -1 . All the microalgae could recover from the toxicity of high concentrations of ENR during cultivation. The biochemical characteristics (total chlorophyll, carotenoid, and malondialdehyde) were significantly influenced by ENR (1-100 mg L -1 ) stress. The individual microalgae species and microalgae consortium removed 18-26% ENR at day 11. Although the microalgae consortium showed a higher sensitivity (with lower EC 50 ) toward ENR than the individual microalgae species, the removal efficiency of ENR by the constructed microalgae consortium was comparable to that of the most effective microalgal species. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. MICROALGAS E SEU POTENCIAL DE USO

    OpenAIRE

    Barcellos, Amanda Desireux; UFBA; Barreto, Antonio Geraldo da Silva Sá; UFBA; Machado, Bruna Aparecida Souza; UFBA; Druzian, Janice Izabel; UFBA

    2014-01-01

    As microalgas são organismos predominantemente microscópicos unicelulares, procariontes ou eucariontes, dotados de pigmentos e fotoautotróficos. Estes seres possuem um alto potencial biológico, ecológico e econômico. O objetivo desta prospecção tecnológica foi identificar as patentes, teses e artigos científicos referentes a microalgas quanto ao seu emprego nos mais diversos setores, bem como sua tecnologia de cultivo. Para tanto, foi realizada uma pesquisa aos bancos de dados de patentes nac...

  16. Nutrient recycle from defatted microalgae (Aurantiochytrium) with hydrothermal treatment for microalgae cultivation.

    Science.gov (United States)

    Aida, Taku Michael; Maruta, Ryouma; Tanabe, Yuuhiko; Oshima, Minori; Nonaka, Toshiyuki; Kujiraoka, Hiroki; Kumagai, Yasuaki; Ota, Masaki; Suzuki, Iwane; Watanabe, Makoto M; Inomata, Hiroshi; Smith, Richard L

    2017-03-01

    Defatted heterotrophic microalgae (Aurantiochytrium limacinum SR21) was treated with high temperature water (175-350°C, 10-90min) to obtain nitrogen and phosphorous nutrients as a water soluble fraction (WS). Yields of nitrogen and phosphorous recovered in WS varied from 38 to 100% and from 57 to 99%, respectively. Maximum yields of nitrogen containing compounds in WS were proteins (43%), amino acids (12%) and ammonia (60%) at treatment temperatures of 175, 250 and 350°C, respectively. Maximum yield of phosphorous in WS was 99% at a treatment temperature of 250°C. Cultivation experiments of microalgae (A. limacinum SR21) using WS obtained at 200 and 250°C showed positive growth. Water soluble fractions from hydrothermal treatment of defatted microalgae are effective nitrogen and phosphorous nutrient sources for microalgae cultivation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Potentials of Microalgae Biodiesel Production in Nigeria

    African Journals Online (AJOL)

    Prof. Ogunji

    production industries in Nigeria will have positive effects on socio-economic development ... Keywords: bio-energy; climatic conditions; fossil fuel; microalgae; production economics ... of affordable land and labour (Sielhorst et al., ..... by clouds. Closed photobioreactors are scarcely influenced by rainfall pattern; however, ...

  18. Secondary wastewater treatment by microalgae isolated from ...

    African Journals Online (AJOL)

    Microalgae play a fundamental role in primary and secondary wastewater treatment. In this work the growth, photosynthetic activity and removal of phosphorus from wastewater effluents by indigenous blue-green algal species, Spirulina and Oscillatoria, isolated from Gaborone oxidation ponds was studied. Oscillatoria and ...

  19. Hydrothermal Liquefaction of the Microalgae Phaeodactylum tricornutum

    DEFF Research Database (Denmark)

    Sigaard Christensen, Per; Peng, Gaël; Vogel, Frédéric

    2014-01-01

    The microalgae Phaeodactylum tricornutum was processed by hydrothermal liquefaction in order to assess the influence of reaction temperature and reaction time on the product and elemental distribution. The experiments were carried out at different reaction times (5 and 15 min) and over a wide range...

  20. Harvesting of microalgae by bio-flocculation

    NARCIS (Netherlands)

    Salim, S.; Bosma, R.; Vermuë, M.H.; Wijffels, R.H.

    2011-01-01

    The high-energy input for harvesting biomass makes current commercial microalgal biodiesel production economically unfeasible. A novel harvesting method is presented as a cost and energy efficient alternative: the bio-flocculation by using one flocculating microalga to concentrate the

  1. Microalgae biorefineries: The Brazilian scenario in perspective.

    Science.gov (United States)

    Brasil, B S A F; Silva, F C P; Siqueira, F G

    2017-10-25

    Biorefineries have the potential to meet a significant part of the growing demand for energy, fuels, chemicals and materials worldwide. Indeed, the bio-based industry is expected to play a major role in energy security and climate change mitigation during the 21th century. Despite this, there are challenges related to resource consumption, processing optimization and waste minimization that still need to be overcome. In this context, microalgae appear as a promising non-edible feedstock with advantages over traditional land crops, such as high productivity, continuous harvesting throughout the year and minimal problems regarding land use. Importantly, both cultivation and microalgae processing can take place at the same site, which increases the possibilities for process integration and a reduction in logistic costs at biorefinery facilities. This review describes the actual scenario for microalgae biorefineries integration to the biofuels and petrochemical industries in Brazil, while highlighting the major challenges and recent advances in microalgae large-scale production. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Antenna size reduction in microalgae mass culture

    NARCIS (Netherlands)

    Mooij, de T.

    2016-01-01

    The thesis describes the potential of microalgae with a reduced light harvesting antenna for biomass production under mass culture conditions (high biomass density, high light intensity). Theoretically, the lower chlorophyll content reduces the light harvesting capacity and with that the amount

  3. Production of structured triacylglycerols from microalgae

    Czech Academy of Sciences Publication Activity Database

    Řezanka, Tomáš; Lukavský, Jaromír; Nedbalová, Linda; Sigler, Karel

    2014-01-01

    Roč. 104, AUG 2014 (2014), s. 95-104 ISSN 0031-9422 R&D Projects: GA ČR(CZ) GAP503/11/0215 Institutional support: RVO:61388971 ; RVO:67985939 Keywords : microalgae * enantiomers * chiral LC Subject RIV: EE - Microbiology, Virology Impact factor: 2.547, year: 2014

  4. Investigation of microalgae with photon density waves

    Science.gov (United States)

    Frankovitch, Christine; Reich, Oliver; Löhmannsröben, Hans-Gerd

    2007-09-01

    Phototropic microalgae have a large potential for producing valuable substances for the feed, food, cosmetics, pigment, bioremediation, and pharmacy industries as well as for biotechnological processes. Today it is estimated that the microalgal aquaculture worldwide production is 5000 tons of dry matter per year (not taking into account processed products) making it an approximately $1.25 billion U.S. per year industry. For effective observation of the photosynthetic growth processes, fast on-line sensor systems that analyze the relevant biological and technical process parameters are preferred. The optical properties of the microalgae culture influence the transport of light in the photobioreactor and can be used to extract relevant information for efficient cultivation practices. Microalgae cultivation media show a combination of light absorption and scattering, which are influenced by the concentrations and the physical and chemical properties of the different absorbing and scattering species (e.g. pigments, cell components, etc.). Investigations with frequency domain photon density waves (PDW) allow for the examination of absorption and scattering properties of turbid media, namely the absorption and reduced scattering coefficient. The reduced scattering coefficient can be used to characterize physical and morphological properties of the medium, including the cell concentration, whereas the absorption coefficient correlates with the pigment content. Nannochloropsis oculata, a single-cell species of microalgae, were examined in a nutrient solution with photon density waves. The absorption and reduced scattering coefficients were experimentally determined throughout the cultivation process, and applied to gain information about the cell concentration and average cell radius.

  5. hydroprocessing processing processing microalgae derived h

    African Journals Online (AJOL)

    eobe

    higher yield of fuel per unit microalgae than the other ... used for the bio-crude production, it is not mandatory ... convert the whole biomass into primarily liquid .... Typical catalysts reportedly used for hydroprocessing ... design and economics for the conversion of whole ... separate reactors or a two-in-one reactor with a.

  6. Scenario evaluation of open pond microalgae production

    NARCIS (Netherlands)

    Slegers, P.M.; Lösing, M.B.; Wijffels, R.H.; Straten, van G.; Boxtel, van A.J.B.

    2013-01-01

    To evaluate microalgae production in large scale open ponds under different climatologic conditions, a model-based framework is used to study the effect of light conditions, water temperature and reactor design on trends in algae productivity. Scenario analyses have been done for two algae species

  7. Harvesting microalgae with microwave synthesized magnetic microparticles

    Czech Academy of Sciences Publication Activity Database

    Procházková, G.; Šafařík, Ivo; Brányik, T.

    2013-01-01

    Roč. 130, FEB (2013), s. 472-477 ISSN 0960-8524 R&D Projects: GA MŠk LH12190 Institutional support: RVO:67179843 Keywords : harvesting microalgae * iron oxide magnetic microparticles * non-covalent interactions * microwave treatment * cell demagnetization Subject RIV: EI - Biotechnology ; Bionics Impact factor: 5.039, year: 2013

  8. Biomass and oil production by Chlorella vulgaris and four other microalgae - Effects of salinity and other factors.

    Science.gov (United States)

    Luangpipat, Tiyaporn; Chisti, Yusuf

    2017-09-10

    Five nominally freshwater microalgae (Chlorella vulgaris, Choricystis minor, Neochloris sp., Pseudococcomyxa simplex, Scenedesmus sp.) with a known ability to produce high-levels of lipids for possible use as fuel oils were evaluated for their ability to thrive and produce lipids in seawater and brackish water. Only C. vulgaris was found to thrive and produce lipids in full strength seawater. Seawater tolerant strains of C. vulgaris are unusual. Lipid productivity in nutrient sufficient seawater exceeded 37mgL -1 d -1 and was nearly 2-fold greater than in freshwater. Although other microalgae such as C. minor had higher lipid productivities (e.g. 45mgL -1 d -1 ), they did not thrive in seawater. The lipid content of the C. vulgaris biomass was nearly 16% by dry weight. The calorific value of the seawater-grown C. vulgaris biomass exceeded 25kJg -1 . Compared to continuously illuminated cultures, a 12/12h light-dark cycle reduced lipid productivity of C. vulgaris by ∼30%, but did not affect the lipid content of the biomass. Biomass yield on phosphate was nearly 27% higher in seawater compared to in freshwater. While C. vulgaris has been extensively studied in freshwater, it has not been examined to any detail in full strength seawater. Studies in seawater are essential for any future large scale production of algal oils for biofuels: seawater is available cheaply and in large amounts whereas there is a global shortage of freshwater. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Growth and fatty acid characterization of microalgae isolated from municipal waste-treatment systems and the potential role of algal-associated bacteria in feedstock production

    Directory of Open Access Journals (Sweden)

    Kevin Stemmler

    2016-03-01

    Full Text Available Much research has focused on growing microalgae for biofuel feedstock, yet there remain concerns about the feasibility of freshwater feedstock systems. To reduce cost and improve environmental sustainability, an ideal microalgal feedstock system would be fed by municipal, agricultural or industrial wastewater as a main source of water and nutrients. Nonetheless, the microalgae must also be tolerant of fluctuating wastewater quality, while still producing adequate biomass and lipid yields. To address this problem, our study focused on isolating and characterizing microalgal strains from three municipal wastewater treatment systems (two activated sludge and one aerated-stabilization basin systems for their potential use in biofuel feedstock production. Most of the 19 isolates from wastewater grew faster than two culture collection strains under mixotrophic conditions, particularly with glucose. The fastest growing wastewater strains included the genera Chlorella and Dictyochloris. The fastest growing microalgal strains were not necessarily the best lipid producers. Under photoautotrophic and mixotrophic growth conditions, single strains of Chlorella and Scenedesmus each produced the highest lipid yields, including those most relevant to biodiesel production. A comparison of axenic and non-axenic versions of wastewater strains showed a notable effect of commensal bacteria on fatty acid composition. Strains grown with bacteria tended to produce relatively equal proportions of saturated and unsaturated fatty acids, which is an ideal lipid blend for biodiesel production. These results not only show the potential for using microalgae isolated from wastewater for growth in wastewater-fed feedstock systems, but also the important role that commensal bacteria may have in impacting the fatty acid profiles of microalgal feedstock.

  10. 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.

  11. Mixotrophic cultivation of microalgae using industrial flue gases for biodiesel production.

    Science.gov (United States)

    Kandimalla, Pooja; Desi, Sreekanth; Vurimindi, Himabindu

    2016-05-01

    In the present study, an attempt has been made to grow microalgae Scenedesmus quadricauda, Chlorella vulgaris and Botryococcus braunii in mixotropic cultivation mode using two different substrates, i.e. sewage and glucose as organic carbon sources along with flue gas inputs as inorganic carbon source. The experiments were carried out in 500 ml flasks with sewage and glucose-enriched media along with flue gas inputs. The composition of the flue gas was 7 % CO2, 210 ppm of NO x and 120 ppm of SO x . The results showed that S. quadricauda grown in glucose-enriched medium yielded higher biomass, lipid and fatty acid methyl esters (FAME) (biodiesel) yields of 2.6, 0.63 and 0.3 g/L, respectively. Whereas with sewage, the biomass, lipid and FAME yields of S. quadricauda were 1.9, 0.46, and 0.21 g/L, respectively. The other two species showed closer results as well. The glucose utilization was measured in terms of Chemical Oxygen Demand (COD) reduction, which was up to 93.75 % by S. quadricauda in the glucose-flue gas medium. In the sewage-flue gas medium, the COD removal was achieved up to 92 % by S. quadricauda. The other nutrients and pollutants from the sewage were removed up to 75 % on an average by the same. Concerning the flue gas treatment studies, S. quadricauda could remove CO2 up to 85 % from the flue gas when grown in glucose medium and 81 % when grown in sewage. The SO x and NO x concentrations were reduced up to 50 and 62 %, respectively, by S. quadricauda in glucose-flue gas medium. Whereas, in the sewage-flue gas medium, the SO x and NO x concentrations were reduced up to 45 and 50 %, respectively, by the same. The other two species were equally efficient however with little less significant yields and removal percentages. This study laid emphasis on comparing the feasibility in utilization of readily available carbon sources like glucose and inexpensive leftover carbon sources like sewage by microalgae to generate energy coupled with economical

  12. Simultaneous nitrogen, phosphorous, and hardness removal from reverse osmosis concentrate by microalgae cultivation.

    Science.gov (United States)

    Wang, Xiao-Xiong; Wu, Yin-Hu; Zhang, Tian-Yuan; Xu, Xue-Qiao; Dao, Guo-Hua; Hu, Hong-Ying

    2016-05-01

    While reverse osmosis (RO) is a promising technology for wastewater reclamation, RO concentrate (ROC) treatment and disposal are important issues to consider. Conventional chemical and physical treatment methods for ROC present certain limitations, such as relatively low nitrogen and phosphorus removal efficiencies as well as the requirement of an extra process for hardness removal. This study proposes a novel biological approach for simultaneous removal of nitrogen, phosphorus, and calcium (Ca(2+)) and magnesium (Mg(2+)) ions from the ROC of municipal wastewater treatment plants by microalgal cultivation and algal biomass production. Two microalgae strains, Chlorella sp. ZTY4 and Scenedesmus sp. LX1, were used for batch cultivation of 14-16 days. Both strains grew well in ROC with average biomass production of 318.7 mg/L and lipid contents up to 30.6%, and nitrogen and phosphorus could be effectively removed with efficiencies of up to 89.8% and 92.7%, respectively. Approximately 55.9%-83.7% Ca(2+) could be removed from the system using the cultured strains. Mg(2+) removal began when Ca(2+) precipitation ceased, and the removal efficiency of the ion could reach up to 56.0%. The most decisive factor influencing Ca(2+) and Mg(2+) removal was chemical precipitation with increases in pH caused by algal growth. The results of this study provide a new biological approach for removing nitrogen, phosphorous, and hardness from ROC. The results suggest that microalgal cultivation presents new opportunities for applying an algal process to ROC treatment. The proposed approach serves dual purposes of nutrient and hardness reduction and production of lipid rich micro-algal biomass. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Evaluation of the Antioxidant Activity of Cell Extracts from Microalgae

    OpenAIRE

    F. Xavier Malcata; Pedro Moradas-Ferreira; Paula Tamagnini; A. C. Silva Ferreira; Maria S. Gião; Rui Seabra; A. Catarina Guedes

    2013-01-01

    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 complem...

  14. Lipid extraction from microalgae using a single ionic liquid

    Science.gov (United States)

    Salvo, Roberto Di; Reich, Alton; Dykes, Jr., H. Waite H.; Teixeira, Rodrigo

    2013-05-28

    A one-step process for the lysis of microalgae cell walls and separation of the cellular lipids for use in biofuel production by utilizing a hydrophilic ionic liquid, 1-butyl-3-methylimidazolium. The hydrophilic ionic liquid both lyses the microalgae cell walls and forms two immiscible layers, one of which consists of the lipid contents of the lysed cells. After mixture of the hydrophilic ionic liquid with a suspension of microalgae cells, gravity causes a hydrophobic lipid phase to move to a top phase where it is removed from the mixture and purified. The hydrophilic ionic liquid is recycled to lyse new microalgae suspensions.

  15. Review on biofuel oil and gas production processes from microalgae

    International Nuclear Information System (INIS)

    Amin, Sarmidi

    2009-01-01

    Microalgae, as biomass, are a potential source of renewable energy, and they can be converted into energy such as biofuel oil and gas. This paper presents a brief review on the main conversion processes of microalgae becoming energy. Since microalgae have high water content, not all biomass energy conversion processes can be applied. By using thermochemical processes, oil and gas can be produced, and by using biochemical processes, ethanol and biodiesel can be produced. The properties of the microalgae product are almost similar to those of offish and vegetable oils, and therefore, it can be considered as a substitute of fossil oil.

  16. Learning sustainability by developing a solar dryer for microalgae retrieval

    Directory of Open Access Journals (Sweden)

    Benedita Malheiro

    2016-01-01

    Full Text Available Excessive fossil fuel consumption is driving the search for alternative energy production solutions and, in particular, for sustainable sources of energy such as microalgae, from which biodiesel, among other useful compounds, can be obtained. After producing the microalgae, they must be harvested and dried. Existing drying solutions consume too much energy and are, therefore, expensive and unsustainable. The goal of this EPS@ISEP Spring 2013 project was to develop a solar microalgae dryer for the microalgae laboratory of ISEP. A multinational team of five students from distinct fields of study was responsible for designing and building the solar microalgae dryer prototype. The prototype includes a control system to ensure that the microalgae are not destroyed during the drying process. The solar microalgae dryer works as a distiller, extracting the excess water from the microalgae suspension. This paper details the design steps, the building technologies, the ethical and sustainable concerns and compares the prototype with existing solutions. The proposed sustainable microalgae drying process is competitive as far as energy usage is concerned. Finally, the project contributed to increase the team’s sustainable development awareness, active learning and motivation.

  17. Microalgae: cultivation techniques and wastewater phycoremediation.

    Science.gov (United States)

    Pacheco, Marcondes M; Hoeltz, Michele; Moraes, Maria S A; Schneider, Rosana C S

    2015-01-01

    Generation of liquid and gaseous effluents is associated with almost all anthropogenic activities. The discharge of these effluents into the environment without treatment has reduced the availability and quality of natural resources, representing a serious threat to the balance of different ecosystems and human health. Universal access to water and global warming are topics of intense concern and are listed as priorities in the vast majority of global scientific, social and political guidelines. Conventional techniques to treat liquid and gaseous effluents pose economic and/or environmental limitations that prevent their use in certain applications. The technique of phycoremediation, which uses microalgae, macroalgae, and cyanobacteria for the removal or biotransformation of pollutants, is an emerging technology that has been highlighted due to its economic viability and environmental sustainability. This literature review discusses different techniques of microalgae cultivation and their use in the phycoremediation of contaminants in wastewater.

  18. Microalgae for Biofuels and Animal Feeds

    Directory of Open Access Journals (Sweden)

    John Benemann

    2013-11-01

    Full Text Available The potential of microalgae biomass production for low-cost commodities—biofuels and animal feeds—using sunlight and CO2 is reviewed. Microalgae are currently cultivated in relatively small-scale systems, mainly for high value human nutritional products. For commodities, production costs must be decreased by an order of magnitude, and high productivity algal strains must be developed that can be stably cultivated in large open ponds and harvested by low-cost processes. For animal feeds, the algal biomass must be high in digestible protein and long-chain omega-3 fatty acids that can substitute for fish meal and fish oils. Biofuels will require a high content of vegetable oils (preferably triglycerides, hydrocarbons or fermentable carbohydrates. Many different cultivation systems, algal species, harvesting methods, and biomass processing technologies are being developed worldwide. However, only raceway-type open pond systems are suitable for the production of low-cost commodities.

  19. Antioxidant activity of the microalga Spirulina maxima

    OpenAIRE

    Miranda M.S.; Cintra R.G.; Barros S.B.M.; Mancini-Filho J.

    1998-01-01

    Spirulina maxima, which is used as a food additive, is a microalga rich in protein and other essential nutrients. Spirulina contains phenolic acids, tocopherols and ß-carotene which are known to exhibit antioxidant properties. The aim of the present study was to evaluate the antioxidant capacity of a Spirulina extract. The antioxidant activity of a methanolic extract of Spirulina was determined in vitro and in vivo. The in vitro antioxidant capacity was tested on a brain homogenate incubated ...

  20. Energy from biomass production - photosynthesis of microalgae?

    Energy Technology Data Exchange (ETDEWEB)

    Lamparter, Tilman [Universitaet Karlsruhe, Botanisches Institut, Geb. 10.40, Kaiserstr. 2, D-76131 Karlsruhe (Germany)

    2009-07-01

    The composition of our atmosphere in the past, present and future is largely determined by photosynthetic activity. Other biological processes such as respiration consume oxygen and produce, like the use of the limited fossil fuel resources, CO{sub 2} whose increasing atmospheric concentration is a major concern. There is thus a demand on the development of alternative energy sources that replace fossil fuel. The use of crop plants for the production of biofuel is one step towards this direction. Since most often the same areas are used as for the production of food, the increased production of biofuel imposes secondary problems, however. In this context, the use of microalgae for biomass production has been proposed. Not only algae in the botanical sense (lower plants, photosynthetic eukaryotes) but also cyanobacteria, which belong to the prokaryotes, are used as ''microalgae''. The conversion of light energy into biomass can reach much higher efficiencies than in crop plants, in which a great portion of photosynthesis products is used to build up non-photosynthetic tissues such as roots or stems. Microalgae can grow in open ponds or bioreactors and can live on water of varying salinity. It has been proposed to grow microalgae in sea water on desert areas. Ongoing research projects aim at optimizing growth conditions in bioreactors, the recycling of CO{sub 2} from flue gases (e.g. from coal-fired power plants), the production of hydrogen, ethanol or lipids, and the production of valuable other substances such as carotenoids.

  1. 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.

  2. Innovative natural functional ingredients from microalgae.

    Science.gov (United States)

    Plaza, Merichel; Herrero, Miguel; Cifuentes, Alejandro; Ibáñez, Elena

    2009-08-26

    Nowadays, a wide variety of compounds such as polyphenols, polyunsaturated fatty acids (PUFA), or phytosterols obtained, for example, from wine, fish byproducts, or plants are employed to prepare new functional foods. However, unexplored natural sources of bioactive ingredients are gaining much attention since they can lead to the discovery of new compounds or bioactivities. Microalgae have been proposed as an interesting, almost unlimited, natural source in the search for novel natural functional ingredients, and several works have shown the possibility to find bioactive compounds in these organisms. Some advantages can be associated with the study of microalgae such as their huge diversity, the possibility of being used as natural reactors at controlled conditions, and their ability to produce active secondary metabolites to defend themselves from adverse or extreme conditions. In this contribution, an exhaustive revision is presented involving the research for innovative functional food ingredients from microalgae. The most interesting results in this promising field are discussed including new species composition and bioactivity and new processing and extraction methods. Moreover, the future research trends are critically commented.

  3. Production of biodiesel from Coelastrella sp. microalgae

    Science.gov (United States)

    Mansur, Dieni; Fitriady, Muhammad Arifuddin; Susilaningsih, Dwi; Simanungkalit, Sabar Pangihutan

    2017-11-01

    Microalgae have a wide area of usage and one of them it can be used for biodiesel production. In biodiesel production, lipids containing triglyceride or free fatty acid are converted into methyl ester through trans/esterification reactions. Lipids from microalgae can be extracted by acetone and dimethyl carbonate using homogenizer. Esterification of the lipids was investigated using various catalysts and source of methyl group. Activity of homogeneous catalyst such as HCl and H2SO4 and heterogeneous catalysts such as montmorillonit K-10 and ledgestone was investigated. Moreover, methanol and dimethyl carbonate as source of methyl group were also studied. Among of catalysts with methanol as source of methyl group, it was found that yield of crude biodiesel derived from Choelestrella Sp. microalgae was high over H2SO4 catalyst. On the other hand, over H2SO4 catalyst using dimethyl carbonate as source of methyl group, yield of crude biodiesel significant increase. However, FAME composition of crude biodiesel was high over HCl catalyst.

  4. Efficient recovery of uranium using genetically improved microalgae; Recuperacion eficaz de uranio utilizando microalgas geneticamente mejoradas

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Rodas, V.; Conde Vilda, E.; Garcia-Balboa, C.

    2015-07-01

    We propose an alternative process for the efficient recovery of dissolved uranium based on genetically improved microalgae. We isolate Chlamydomonas cf. fonticola from a pond extremely contaminated by uranium (∼ 25 ppm) from ENUSA U-mine, Saelices (Salamanca, Spain). After a process of genetic improvement we obtained a strain capable to recover 115 mg of U per g of dry weight, by mean of bio-adsorption on the cell wall (mostly) and intra-cytoplasm bioaccumulation. Such a genetically improved microalgae resist extremes of acidity and pollution, but even its dead biomass is still able to recover a large amount of uranium. (Author)

  5. Antioxidative properties of some phototropic microalgae grown in waste water

    DEFF Research Database (Denmark)

    Safafar, Hamed; Jacobsen, Charlotte; Møller, Peter

    for the screening and selection of the species. In this study,the potential antioxidant activities of 12 micro algal sample from Chlorella., Spirulina., Euglena, Scenedesmus and Haematococcus species grown in waste water in Kalundborg micro algal facilities were evaluated using three antioxidant assays, including...

  6. Assessment of microalgae-influenced biodeterioration of concrete ...

    African Journals Online (AJOL)

    The aim of this study was to isolate microalga involved in the biodeterioration of concrete structures. The growth of algae was monitored between day 1 and 18 using a spectrophotometer (Spectronic 721 model) at varying pH (4.2 and 9.4). To identify the microalgae, aliquots of the isolates was placed on microscope slides ...

  7. Novel protocol for lutein extraction from microalga Chlorella vulgaris

    DEFF Research Database (Denmark)

    D'Este, Martina; De Francisci, Davide; Angelidaki, Irini

    2017-01-01

    Lutein is a pigment generally extracted from marigold flowers. However, lutein is also found in considerable amounts in microalgae. In this study a novel method was developed to improve the extraction efficiency of lutein from microalga C. vulgaris. Differently from conventional methods, ethanol...

  8. Chemical Profiles of Microalgae with Emphasis on Lipids: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Benemann, J. R.; Tillett, D. M.; Suen, Y.; Hubbard, J.; Tornabene, T. G.

    1986-02-01

    This final report details progress during the third year of this subcontract. The overall objective of this subcontract was two fold: to provide the analytical capability required for selecting microalgae strains with high energy contents and to develop fundamental knowledge required for optimizing the energy yield from microalgae cultures. The progress made towards these objectives during this year is detailed in this report.

  9. Techno-economical evaluation of protein extraction for microalgae biorefinery

    NARCIS (Netherlands)

    Sari, Y.W.; Sanders, J.P.M.; Bruins, M.

    2016-01-01

    Due to scarcity of fossil feedstocks, there is an increasing demand for biobased fuels. Microalgae are considered as promising biobased feedstocks. However, microalgae based fuels are not yet produced at large scale at present. Applying biorefinery, not only for oil, but also for other

  10. A mathematical model of microalgae growth in cylindrical photobioreactor

    Science.gov (United States)

    Bakeri, Noorhadila Mohd; Jamaian, Siti Suhana

    2017-08-01

    Microalgae are unicellular organisms, which exist individually or in chains or groups but can be utilized in many applications. Researchers have done various efforts in order to increase the growth rate of microalgae. Microalgae have a potential as an effective tool for wastewater treatment, besides as a replacement for natural fuel such as coal and biodiesel. The growth of microalgae can be estimated by using Geider model, which this model is based on photosynthesis irradiance curve (PI-curve) and focused on flat panel photobioreactor. Therefore, in this study a mathematical model for microalgae growth in cylindrical photobioreactor is proposed based on the Geider model. The light irradiance is the crucial part that affects the growth rate of microalgae. The absorbed photon flux will be determined by calculating the average light irradiance in a cylindrical system illuminated by unidirectional parallel flux and considering the cylinder as a collection of differential parallelepipeds. Results from this study showed that the specific growth rate of microalgae increases until the constant level is achieved. Therefore, the proposed mathematical model can be used to estimate the rate of microalgae growth in cylindrical photobioreactor.

  11. 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.

  12. 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

  13. 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.

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

    Directory of Open Access Journals (Sweden)

    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

  15. Radio photosynthesis of some 14 C-labelled sugars using the unicellular green alga scenedesmus ACUTUS

    International Nuclear Information System (INIS)

    Barakat, M.F.; Farag, A.N.; Ragab, M.T.; El-Fouly, M.M.; El-Baz, F.K.

    1993-01-01

    Radiosynthesis has been carried out using the unicellular green alga scenedesmus acutus together with Na H 14 CO 3 solution as a carbon-14 source, in an ordinary photosynthesis chamber. The process is more easier and less laborious than the techniques involving the use of gaseous 14 CO 2 in a tight photosynthesis chamber. Uniformly labelled 14 C-glucose, 14 C-fructose and 14 C-sucrose have been prepared with specific activities of several micro curies per milli mole. The specific activity of the products was found to increase on increasing the photosynthesis time or the initial activity of the Na H 14 CO 3 solution used. 3 tabs

  16. Growth acceleration and photosynthesis of the scenedesmus algae and cocconeis algae in deuterium water

    International Nuclear Information System (INIS)

    Liu Feng; Wang Wenqing

    1998-01-01

    In order to find new way to treat the radioactive tritium waste water, scenedesmus algae and cocconeis algae are cultured in medium which contains 30% (w) deuterium water. During different time, activities of photosymthesis, absorption spectrum, growth rate and low-temperature fluorescence spectrum are measured. Accelerated growth is found in the deuterium water compared to the normal water. Activities of photosynthesis show the similar result (F v /F m ) to the growth data. It is also concluded from low-temperature fluorescence spectra that algae activities in the deuterium water, which are expressed by PS I/PS II, are more sensitive than those in the normal water

  17. Microalgae for Bioenergy; Key Technology Nodes

    Czech Academy of Sciences Publication Activity Database

    Maléterová, Ywetta; Kaštánek, František; Rousková, Milena; Matějková, Martina; Kaštánek, P.; Šolcová, Olga

    2015-01-01

    Roč. 2015, č. 2015 (2015), s. 597618 ISSN 1537-744X R&D Projects: GA MŠk LJ12002 Institutional support: RVO:67985858 Keywords : microalgae * oil production * water recycling Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.219, year: 2013 http://apps.webofknowledge.com/full_record.do?product=UA&search_mode=GeneralSearch&qid=14&SID=V2kH1WLyceq9ctvzW8I&page=1&doc=1

  18. Towards Sustainable Production of Biofuels from Microalgae

    Directory of Open Access Journals (Sweden)

    Hans Ragnar Giselrød

    2008-07-01

    Full Text Available Renewable and carbon neutral biofuels are necessary for environmental and economic sustainability. The viability of the first generation biofuels production is however questionable because of the conflict with food supply. Microalgal biofuels are a viable alternative. The oil productivity of many microalgae exceeds the best producing oil crops. This paper aims to analyze and promote integration approaches for sustainable microalgal biofuel production to meet the energy and environmental needs of the society. The emphasis is on hydrothermal liquefaction technology for direct conversion of algal biomass to liquid fuel.

  19. 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

  20. Influence of mineral medium components - calcium, phosphorus and potasium - on carotenoid biosynthesis in the alga Scenedesmus acuminatus

    Directory of Open Access Journals (Sweden)

    Anna Sykuta

    2015-01-01

    Full Text Available From the alga Scenedesmus acuminatus 10 carotenoids were isolated: α-carotene, β-carotene, neo-β-carotene, lutein, lutein-5,6-epoxide, violaxanthine, loroxanthine, neoxanthine, antheraxanthine and from old algae - echinenone. Algae cultured on calcium-free medium contained about 60 (per cent cartoenoids less than those from medium with Ca(NO32.

  1. 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 H 2 O 2 treatment decreased the biomass of both the wild type and the mutant. The H 2 O 2 treated mutant when grown in BG11 medium showed an increase in biomass which was in contrast to a decreased biomass observed in the H 2 O 2 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.

  2. 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 -2 s -1 using a flat-plate gas-lift photobioreactor. Highest growth rate (0.11h -1 ) and space-time yield (1.7±0.1g CDW L -1 d -1 ) were observed when applying these reaction conditions. Biomass concentrations of up to 7.5±0.1g CDW L -1 were achieved within six days (25.0±0.5g CDW m -2 d -1 ). The light-dependent growth kinetics of S. ovalternus was identified using Schuster's light transfer model and Andrews' light inhibition model (K S =545μmolphotonsm -2 s -1 ; K I =2744μmolphotonsm -2 s -1 ; μ max =0.21h -1 ). The optimal mean integral photon flux density for growth of S. ovalternus was estimated to be 1223μmolphotonsm -2 s -1 . Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. 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

  4. 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.

  5. Photobioreactor cultivation strategies for microalgae and cyanobacteria.

    Science.gov (United States)

    Johnson, Tylor J; Katuwal, Sarmila; Anderson, Gary A; Gu, Liping; Zhou, Ruanbao; Gibbons, William R

    2018-03-08

    The current burden on fossil-derived chemicals and fuels combined with the rapidly increasing global population has led to a crucial need to develop renewable and sustainable sources of chemicals and biofuels. Photoautotrophic microorganisms, including cyanobacteria and microalgae, have garnered a great deal of attention for their capability to produce these chemicals from carbon dioxide, mineralized water, and solar energy. While there have been substantial amounts of research directed at scaling-up production from these microorganisms, several factors have proven difficult to overcome, including high costs associated with cultivation, photobioreactor construction, and artificial lighting. Decreasing these costs will substantially increase the economic feasibility of these production processes. Thus, the purpose of this review is to describe various photobioreactor designs, and then provide an overview on lighting systems, mixing, gas transfer, and the hydrodynamics of bubbles. These factors must be considered when the goal of a production process is economic feasibility. Targets for improving microalgae and cyanobacteria cultivation media, including water reduction strategies will also be described. As fossil fuel reserves continue to be depleted and the world population continues to increase, it is imperative that renewable chemical and biofuel production processes be developed toward becoming economically feasible. Thus, it is essential that future research is directed toward improving these processes. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 2018. © 2018 American Institute of Chemical Engineers.

  6. Emergent Sources of Prebiotics: Seaweeds and Microalgae.

    Science.gov (United States)

    de Jesus Raposo, Maria Filomena; de Morais, Alcina Maria Miranda Bernardo; de Morais, Rui Manuel Santos Costa

    2016-01-28

    In recent years, scientists have become aware that human microbiota, in general, and gut microbiota, in particular, play a major role in human health and diseases, such as obesity and diabetes, among others. A large number of evidence has come to light regarding the beneficial effects, either for the host or the gut microbiota, of some foods and food ingredients or biochemical compounds. Among these, the most promising seem to be polysaccharides (PS) or their derivatives, and they include the dietary fibers. Some of these PS can be found in seaweeds and microalgae, some being soluble fibers, such as alginates, fucoidans, carrageenans and exopolysaccharides, that are not fermented, at least not completely, by colonic microbiota. This review gives an overview of the importance of the dietary fibers, as well as the benefits of prebiotics, to human health. The potential of the PS from marine macro- and microalgae to act as prebiotics is discussed, and the different techniques to obtain oligosaccharides from PS are presented. The mechanisms of the benefits of fiber, in general, and the types and benefits of algal fibers in human health are highlighted. The findings of some recent studies that present the potential effects of prebiotics on animal models of algal biomass and their extracts, as well as oligo- and polysaccharides, are presented. In the future, the possibility of using prebiotics to modulate the microbiome, and, consequently, prevent certain human diseases is foreseen.

  7. Emergent Sources of Prebiotics: Seaweeds and Microalgae

    Directory of Open Access Journals (Sweden)

    Maria Filomena de Jesus Raposo

    2016-01-01

    Full Text Available In recent years, scientists have become aware that human microbiota, in general, and gut microbiota, in particular, play a major role in human health and diseases, such as obesity and diabetes, among others. A large number of evidence has come to light regarding the beneficial effects, either for the host or the gut microbiota, of some foods and food ingredients or biochemical compounds. Among these, the most promising seem to be polysaccharides (PS or their derivatives, and they include the dietary fibers. Some of these PS can be found in seaweeds and microalgae, some being soluble fibers, such as alginates, fucoidans, carrageenans and exopolysaccharides, that are not fermented, at least not completely, by colonic microbiota. This review gives an overview of the importance of the dietary fibers, as well as the benefits of prebiotics, to human health. The potential of the PS from marine macro- and microalgae to act as prebiotics is discussed, and the different techniques to obtain oligosaccharides from PS are presented. The mechanisms of the benefits of fiber, in general, and the types and benefits of algal fibers in human health are highlighted. The findings of some recent studies that present the potential effects of prebiotics on animal models of algal biomass and their extracts, as well as oligo- and polysaccharides, are presented. In the future, the possibility of using prebiotics to modulate the microbiome, and, consequently, prevent certain human diseases is foreseen.

  8. Electrokinetically controlled fluid injection into unicellular microalgae.

    Science.gov (United States)

    Zhou, Xuewen; Zhang, Xixi; Boualavong, Jonathan; Durney, Andrew R; Wang, Tonghui; Kirschner, Scott; Wentz, Michaela; Mukaibo, Hitomi

    2017-10-01

    Electrokinetically controlled microinjection is reported as an effective transport mechanism for microinjection into the wild-type strain of the widely studied model microalga Chlamydomonas reinhardtii. A microinjection system using glass capillary pipettes was developed to capture and impale the motile cells. To apply an electric field and induce electrokinetic flow (e.g., electrophoresis and electroosmosis), an electrode was inserted directly into the solution inside the impaling injection pipette and another electrode was inserted into the external cell media. The viability of the impaled cells was confirmed for more than an hour under 0.01 V using the fluorescein diacetate/propidium iodide dual fluorescent dye based assay. The viability was also found to increase almost logarithmically with decreasing voltage and to depend strongly on the solution within the injection pipette. Successful electrokinetic microinjection into cells was confirmed by both an increase in cell volume under an applied voltage and electric field dependent delivery of fluorescent fluorescein molecules into an impaled cell. Our study offers novel opportunities for quantitative delivery of biomolecules into microalgae and advancing the research and development of these organisms as biosynthetic factories. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Heterotrophic cultivation of microalgae for production of biodiesel.

    Science.gov (United States)

    Mohamed, Mohd Shamzi; Wei, Lai Zee; Ariff, Arbakariya B

    2011-08-01

    High cell density cultivation of microalgae via heterotrophic growth mechanism could effectively address the issues of low productivity and operational constraints presently affecting the solar driven biodiesel production. This paper reviews the progress made so far in the development of commercial-scale heterotrophic microalgae cultivation processes. The review also discusses on patentable concepts and innovations disclosed in the past four years with regards to new approaches to microalgal cultivation technique, improvisation on the process flow designs to economically produced biodiesel and genetic manipulation to confer desirable traits leading to much valued high lipid-bearing microalgae strains.

  10. 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.

  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. Potential of industrial biotechnology with cyanobacteria and eukaryotic microalgae.

    NARCIS (Netherlands)

    Wijffels, R.H.; Kruse, O.; Hellingwerf, K.J.

    2013-01-01

    Both cyanobacteria and eukaryotic microalgae are promising organisms for sustainable production of bulk products such as food, feed, materials, chemicals and fuels. In this review we will summarize the potential and current biotechnological developments. Cyanobacteria are promising host organisms

  13. Isolation, Characterization and Identification of Microalgae from the Red Sea

    KAUST Repository

    Luque Alaní s, Patricio

    2013-01-01

    Eukaryotic microalgae from the Red Sea were isolated, characterized and identified with the purpose of building a culture collection that will serve future research activities in the area of industrial microbiology. Seven sampling locations were

  14. Phototrophic pigment production with microalgae: biological constraints and opportunities

    NARCIS (Netherlands)

    Mulders, K.J.M.; Lamers, P.P.; Martens, D.E.; Wijffels, R.H.

    2014-01-01

    There is increasing interest in naturally produced colorants, and microalgae represent a bio-technologically interesting source due to their wide range of colored pigments, including chlorophylls (green), carotenoids (red, orange and yellow), and phycobiliproteins (red and blue). However, the

  15. Isolation of microalgae species from arid environments and ...

    African Journals Online (AJOL)

    Isolation of microalgae species from arid environments and evaluation of their potentials for biodiesel production. ... African Journal of Biotechnology. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives.

  16. Climate conditions, and changes, affect microalgae communities… should we worry?

    Science.gov (United States)

    Gimenez Papiol, Gemma

    2018-03-01

    Microalgae play a pivotal role in the regulation of Earth's climate and its cycles, but are also affected by climate change, mainly by changes in temperature, light, ocean acidification, water stratification, and precipitation-induced nutrient inputs. The changes and impacts on microalgae communities are difficult to study, predict, and manage, but there is no doubt that there will be changes. These changes will have impacts beyond microalgae communities, and many of them will be negative. Some actions are currently ongoing for the mitigation of some of the negative impacts, such as harmful algal blooms and water quality, but global efforts for reducing CO 2 emissions, temperature rises, and ocean acidification are paramount for reducing the impact of climate change on microalgae communities, and eventually, on human well-being. Integr Environ Assess Manag 2018;14:181-184. © 2018 SETAC. © 2018 SETAC.

  17. Microalgae as healthy ingredients for functional food: a review.

    Science.gov (United States)

    Matos, J; Cardoso, C; Bandarra, N M; Afonso, C

    2017-08-01

    Microalgae are very interesting and valuable natural sources of highly valuable bioactive compounds, such as vitamins, essential amino acids, polyunsaturated fatty acids, minerals, carotenoids, enzymes and fibre. Due to their potential, microalgae have become some of the most promising and innovative sources of new food and functional products. Moreover, microalgae can be used as functional ingredients to enhance the nutritional value of foods and, thus, to favourably affect human health by improving the well-being and quality of life, but also by curtailing disease and illness risks. This review provides an overview of the current knowledge of the health benefits associated with the consumption of microalgae, bioactive compounds, functional ingredients, and health foods.

  18. Antibacterial and antifungal activities of selected microalgae and cyanobacteria

    Czech Academy of Sciences Publication Activity Database

    Najdenski, H. M.; Gigova, L. G.; Iliev, I. I.; Pilarski, P. S.; Lukavský, Jaromír; Tsvetkova, I. V.; Ninova, M. S.; Kussovski, V. K.

    2013-01-01

    Roč. 48, č. 7 (2013), s. 1533-1540 ISSN 0950-5423 Institutional support: RVO:67985939 Keywords : antimicrobial activity * cyanobacteria * microalgae Subject RIV: EF - Botanics Impact factor: 1.354, year: 2013

  19. Hydrodynamic study of an internal airlift reactor for microalgae culture.

    Science.gov (United States)

    Rengel, Ana; Zoughaib, Assaad; Dron, Dominique; Clodic, Denis

    2012-01-01

    Internal airlift reactors are closed systems considered today for microalgae cultivation. Several works have studied their hydrodynamics but based on important solid concentrations, not with biomass concentrations usually found in microalgae cultures. In this study, an internal airlift reactor has been built and tested in order to clarify the hydrodynamics of this system, based on microalgae typical concentrations. A model is proposed taking into account the variation of air bubble velocity according to volumetric air flow rate injected into the system. A relationship between riser and downcomer gas holdups is established, which varied slightly with solids concentrations. The repartition of solids along the reactor resulted to be homogenous for the range of concentrations and volumetric air flow rate studied here. Liquid velocities increase with volumetric air flow rate, and they vary slightly when solids are added to the system. Finally, liquid circulation time found in each section of the reactor is in concordance with those employed in microalgae culture.

  20. Microalgae, a Potential Natural Functional Food Source – a Review

    Directory of Open Access Journals (Sweden)

    Villarruel-López Angélica

    2017-12-01

    Full Text Available Microalgae are a group of microorganisms used in aquaculture. The number of studies regarding their use as a functional food has recently increased due to their nutritional and bioactive compounds such as polysaccharides, fatty acids, bioactive peptides, and pigments. Specific microalgal glucans (polysaccharides can activate the immune system or exert antioxidant and hypocholesterolemic effects. The importance of algal lipids is based on their polyunsaturated fatty acids, their anti-inflammatory effects, their modulation of lipid pathways, and their neuroprotective action. Microalgae peptides can bind or inhibit specific receptors in cardiovascular diseases and cancer, while carotenoids can act as potent antioxidants. The beneficial biological activity will depend on the specific microalga and its chemical constituents. Therefore, knowledge of the composition of microalgae would aid in identifying, selecting, and studying their functional effects.

  1. Growth parameters of microalgae tolerant to high levels of carbon dioxide in batch and continuous-flow photobioreactors

    Energy Technology Data Exchange (ETDEWEB)

    Westerhoff, P.; Hu, Q.; Esparza-Soto, M.; Vermaas, W. [Dept. of Civil & Environmental Engineering, Tempe, AZ (United States)

    2010-07-01

    Microalgae can be cultured in photobioreactors to sequester carbon dioxide and produce potentially valuable biomaterials. The goal of the present study was to identify and utilize microalgal strains that are capable of tolerating up to 20% CO{sub 2} (gas phase) concentrations under variable light or flue-gas blend conditions and reactor configurations to produce biomass. Scenedesmus sp. and Chlorella sp., both cultured from a Sonoran desert mineral spring, grew well and tolerated exposure to a gas mixture containing up to 20% CO{sub 2} applied continuously in batch reactors to the culture. Experiments were conducted with simulated coal-powered acidic flue gases containing SOx/NOx at concentrations of 200 to 350 ppmV. Microalgae did not grow well without pH control, and high levels (> 250 mM) of nitrite or sulphite in the liquid media inhibited algal growth. Pseudo steady-state experiments were also conducted using helical tubular and flat-plate photobioreactors with continuous flow (water and gas) and with artificial or natural sunlight. With a 2 d hydraulic residence time (HRT), the helical tubular photobioreactor produced 0.50 {+-} 0.11 g C d{sup -1} (0.056 {+-} 0.012 g C L{sup -1} d{sup -1}) dry-weight cell mass during continuous fluorescent-lamp irradiance and 0.048 {+-} 0.018 g C L{sup -1} d{sup -1} during 12 h light/darkness cycling. The flat-plate photobioreactor (2 d HRT) produced 0.42 {+-} 0.28 g C L{sup -1} d{sup -1} with artificial lighting and with natural sunlight; a 4 d HRT produced 0.14 {+-} 0.02 g C L{sup -1} d{sup -1}. Reactor modelling indicated that a threshold of reactor size (i.e. HRT) and reactor depth (path-length of light) exists based upon the optical density of the cells in the water column and their growth rates.

  2. POSSIBILITIES OF CARBON DIOXIDE FIXATION BY MICROALGAE IN REFINERY

    OpenAIRE

    Šingliar, Michal; Mikulec, Jozef; Kušnir, Patrik; Polakovičova, Gabriela

    2013-01-01

    Capture and sequestration of carbon dioxide is one of the most critical challenges today for businesses and governments worldwide. Thousands of emitting power plants and industries worldwide face this costly challenge – reduce the CO2 emissions or pay penalties. One possibility for carbon dioxide sequestration is its fixation in microalgae. Microalgae can sequester CO2 from flue gases emitted from fossil fuel-fired refinery plants and units, thereby reducing emissions of a major greenhouse ga...

  3. Biodiesel de microalgas: avanços e desafios

    Directory of Open Access Journals (Sweden)

    André Luiz Custódio Franco

    2013-01-01

    Full Text Available Microalgae biomass has been described by several authors as the raw material with the greatest potential to meet the goals of replacing petroleum diesel by biodiesel while not competing with arable land suitable for food production. Research groups in different countries are seeking the most appropriate production model for productivity, economic viability and environmental sustainability. This review focused on recent advances and challenges of technology for the production of biodiesel from microalgae, including the procedures used to obtain biomass.

  4. Lipid profiling of some authotrophic microalgae grown on waste water

    DEFF Research Database (Denmark)

    Safafar, Hamed; Jacobsen, Charlotte; Møller, Per

    Microalgae can be a new source of lipids for the aquaculture industry. Moreover, their potential as natural sources of antioxidants has gained recent attention. About 40 species of microalgae are used in aquaculture worldwide. A full characterization of lipid components is critical for selecting...... by membrane microfiltration and analyzed for fatty acid (GC), triacylglycerol (HPLC), sterol (GC) and tochol (HPLC) composition and also for amounts of phospholipids . Lipid composition in micro algae varied strongly between species....

  5. Microalgal CO2 sequestering – Modeling microalgae production costs

    International Nuclear Information System (INIS)

    Bilanovic, Dragoljub; Holland, Mark; Armon, Robert

    2012-01-01

    Highlights: ► Microalgae production costs were modeled as a function of specific expenses. ► The effects of uncontrollable expenses/factors were incorporated into the model. ► Modeled microalgae production costs were in the range $102–1503 t −1 ha −1 y −1 . - Abstract: Microalgae CO 2 sequestering facilities might become an industrial reality if microalgae biomass could be produced at cost below $500.00 t −1 . We develop a model for estimation of total production costs of microalgae as a function of known production-specific expenses, and incorporate into the model the effects of uncontrollable factors which affect known production-specific expenses. Random fluctuations were intentionally incorporated into the model, consequently into generated cost/technology scenarios, because each and every logically interconnected equipment/operation that is used in design/construction/operation/maintenance of a production process is inevitably subject to random cost/price fluctuations which can neither be eliminated nor a priori controlled. A total of 152 costs/technology scenarios were evaluated to find 44 scenarios in which predicted total production costs of microalgae (PTPCM) was in the range $200–500 t −1 ha −1 y −1 . An additional 24 scenarios were found with PTCPM in the range of $102–200 t −1 ha −1 y −1 . These findings suggest that microalgae CO 2 sequestering and the production of commercial compounds from microalgal biomass can be economically viable venture even today when microalgae production technology is still far from its optimum.

  6. Techno-Economic Assessment of Micro-Algae Production Systems

    OpenAIRE

    Hoffman, Justin

    2016-01-01

    Global oil consumption is rising at an unprecedented rate renewing interest in alternative fuels. Micro-algae represents a promising feedstock due to inherent advantages such as high solar energy efficiencies, large lipid fractions, and utilization of various waste streams including industrial flue gas. Current technological challenges have limited the commercial viability of microalgae based biofuel production systems. This study directly evaluates and compares the economic viability of biom...

  7. Vibrating membrane filtration as improved technology for microalgae dewatering

    OpenAIRE

    Nurra, C.; Clavero, E.; Salvadó, J.; Torras, C.

    2014-01-01

    10.1016/j.biortech.2014.01.115 The effect of shear-enhanced filtration by vibratory process in microalgae dewatering is presented in this paper. The aim of this research was to investigate the technical performance and improvement of vibrating membrane filtration compared with conventional tangential cross-flow filtration in microalgae concentration. An industrial-scale available commercial set-up was used. Several membrane materials as polyethersulfone, polyacrylonitrile, etc., and mean ...

  8. 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

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

    Directory of Open Access Journals (Sweden)

    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

  10. Effect of Light Intensities and Atmospheric Gas Conditions on Biohydrogen Production of Microalgae Isolated from Fisheries Wastewater

    Directory of Open Access Journals (Sweden)

    Mujalin Pholchan

    2017-06-01

    Full Text Available Recently, the fishery farming industry has been developed rapidly due to increasing demand and consumption as well as the depletion of wild fish resources. Production processes in the industry usually generate large amounts of wastewater containing high nutrients, posing a threat to downstream water. However, phytoplankton removal techniques commonly used to counteract the threat, though appearing to have low efficiency, are timeconsuming and less sustainable. Microalgae are photosynthetic microorganisms that convert solar energy into hydrogen. Using the isolated algae from fish farms as a source of renewable energy production could be a promising choice for handling fisheries wastewater in a more efficient manner. However, hydrogen production processes from algae still need more studies as their efficiencies vary between algae species and growth factors. In this work, the efficiency of hydrogen production from Scenedesmus accuminatus and Arthrospira platensis harvested from fish farms under three different light intensity conditions and three atmospheric gas conditions was determined. The results showed that the best conditions for hydrogen production from both species included 24 h darkness and carbon dioxide addition. Under the atmospheric gas combination of 99% argon and 1% carbon dioxide, S. accuminatus could produce hydrogen gas as high as 0.572 mol H2/mgCh h within 12 h, while the highest hydrogen production (0.348 mol H2/mgCh h obtained from A. platensis was found under the atmospheric gas mixture of 98% argon and 2% carbon dioxide. Interestingly, S. accuminatus appeared to produce more hydrogen than A. platensis under the same conditions.

  11. Bacterial influence on alkenones in live microalgae.

    Science.gov (United States)

    Segev, Einat; Castañeda, Isla S; Sikes, Elisabeth L; Vlamakis, Hera; Kolter, Roberto

    2016-02-01

    The microalga Emiliania huxleyi produces alkenone lipids that are important proxies for estimating past sea surface temperatures. Field calibrations of this proxy are robust but highly variable results are obtained in culture. Here, we present results suggesting that algal-bacterial interactions may be responsible for some of this variability. Co-cultures of E. huxleyi and the bacterium Phaeobacter inhibens resulted in a 2.5-fold decrease in algal alkenone-containing lipid bodies. In addition levels of unsaturated alkenones increase in co-cultures. These changes result in an increase in the reconstructed growth temperature of up to 2°C relative to axenic algal cultures. © 2015 Phycological Society of America.

  12. Marine microalgae attack and feed on metazoans

    DEFF Research Database (Denmark)

    Berge, Terje; Poulsen, Louise K.; Moldrup, Morten

    2012-01-01

    Free-living microalgae from the dinoflagellate genus Karlodinium are known to formmassive blooms in eutrophic coastal waters worldwide and are often associated with fish kills. Natural bloom populations, recently shown to consist of the two mixotrophic and toxic species Karlodinium armiger...... and Karlodinium veneficum have caused fast paralysis and mortality of finfish and copepods in the laboratory, and have been associated with reduced metazooplankton biomass in-situ. Here we show that a strain of K. armiger (K-0688) immobilises the common marine copepod Acartia tonsa in a densitydependent manner...... and collectively ingests the grazer to promote its own growth rate. In contrast, four strains of K. veneficum did not attack or affect the motility and survival of the copepods. Copepod immobilisation by the K. armiger strain was fast (within 15min) and caused by attacks of swarming cells, likely through...

  13. Microalgae - A promising tool for heavy metal remediation.

    Science.gov (United States)

    Suresh Kumar, K; Dahms, Hans-Uwe; Won, Eun-Ji; Lee, Jae-Seong; Shin, Kyung-Hoon

    2015-03-01

    Biotechnology of microalgae has gained popularity due to the growing need for novel environmental technologies and the development of innovative mass-production. Inexpensive growth requirements (solar light and CO2), and, the advantage of being utilized simultaneously for multiple technologies (e.g. carbon mitigation, biofuel production, and bioremediation) make microalgae suitable candidates for several ecofriendly technologies. Microalgae have developed an extensive spectrum of mechanisms (extracellular and intracellular) to cope with heavy metal toxicity. Their wide-spread occurrence along with their ability to grow and concentrate heavy metals, ascertains their suitability in practical applications of waste-water bioremediation. Heavy metal uptake by microalgae is affirmed to be superior to the prevalent physicochemical processes employed in the removal of toxic heavy metals. In order to evaluate their potential and to fill in the loopholes, it is essential to carry out a critical assessment of the existing microalgal technologies, and realize the need for development of commercially viable technologies involving strategic multidisciplinary approaches. This review summarizes several areas of heavy metal remediation from a microalgal perspective and provides an overview of various practical avenues of this technology. It particularly details heavy metals and microalgae which have been extensively studied, and provides a schematic representation of the mechanisms of heavy metal remediation in microalgae. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Potential of industrial biotechnology with cyanobacteria and eukaryotic microalgae.

    Science.gov (United States)

    Wijffels, René H; Kruse, Olaf; Hellingwerf, Klaas J

    2013-06-01

    Both cyanobacteria and eukaryotic microalgae are promising organisms for sustainable production of bulk products such as food, feed, materials, chemicals and fuels. In this review we will summarize the potential and current biotechnological developments. Cyanobacteria are promising host organisms for the production of small molecules that can be secreted such as ethanol, butanol, fatty acids and other organic acids. Eukaryotic microalgae are interesting for products for which cellular storage is important such as proteins, lipids, starch and alkanes. For the development of new and promising lines of production, strains of both cyanobacteria and eukaryotic microalgae have to be improved. Transformation systems have been much better developed in cyanobacteria. However, several products would be preferably produced with eukaryotic microalgae. In the case of cyanobacteria a synthetic-systems biology approach has a great potential to exploit cyanobacteria as cell factories. For eukaryotic microalgae transformation systems need to be further developed. A promising strategy is transformation of heterologous (prokaryotic and eukaryotic) genes in established eukaryotic hosts such as Chlamydomonas reinhardtii. Experimental outdoor pilots under containment for the production of genetically modified cyanobacteria and microalgae are in progress. For full scale production risks of release of genetically modified organisms need to be assessed. Copyright © 2013. Published by Elsevier Ltd.

  15. Microalgae as sustainable renewable energy feedstock for biofuel production.

    Science.gov (United States)

    Medipally, Srikanth Reddy; Yusoff, Fatimah Md; Banerjee, Sanjoy; Shariff, M

    2015-01-01

    The world energy crisis and increased greenhouse gas emissions have driven the search for alternative and environmentally friendly renewable energy sources. According to life cycle analysis, microalgae biofuel is identified as one of the major renewable energy sources for sustainable development, with potential to replace the fossil-based fuels. Microalgae biofuel was devoid of the major drawbacks associated with oil crops and lignocelluloses-based biofuels. Algae-based biofuels are technically and economically viable and cost competitive, require no additional lands, require minimal water use, and mitigate atmospheric CO2. However, commercial production of microalgae biodiesel is still not feasible due to the low biomass concentration and costly downstream processes. The viability of microalgae biodiesel production can be achieved by designing advanced photobioreactors, developing low cost technologies for biomass harvesting, drying, and oil extraction. Commercial production can also be accomplished by improving the genetic engineering strategies to control environmental stress conditions and by engineering metabolic pathways for high lipid production. In addition, new emerging technologies such as algal-bacterial interactions for enhancement of microalgae growth and lipid production are also explored. This review focuses mainly on the problems encountered in the commercial production of microalgae biofuels and the possible techniques to overcome these difficulties.

  16. Microalgae as Sustainable Renewable Energy Feedstock for Biofuel Production

    Directory of Open Access Journals (Sweden)

    Srikanth Reddy Medipally

    2015-01-01

    Full Text Available The world energy crisis and increased greenhouse gas emissions have driven the search for alternative and environmentally friendly renewable energy sources. According to life cycle analysis, microalgae biofuel is identified as one of the major renewable energy sources for sustainable development, with potential to replace the fossil-based fuels. Microalgae biofuel was devoid of the major drawbacks associated with oil crops and lignocelluloses-based biofuels. Algae-based biofuels are technically and economically viable and cost competitive, require no additional lands, require minimal water use, and mitigate atmospheric CO2. However, commercial production of microalgae biodiesel is still not feasible due to the low biomass concentration and costly downstream processes. The viability of microalgae biodiesel production can be achieved by designing advanced photobioreactors, developing low cost technologies for biomass harvesting, drying, and oil extraction. Commercial production can also be accomplished by improving the genetic engineering strategies to control environmental stress conditions and by engineering metabolic pathways for high lipid production. In addition, new emerging technologies such as algal-bacterial interactions for enhancement of microalgae growth and lipid production are also explored. This review focuses mainly on the problems encountered in the commercial production of microalgae biofuels and the possible techniques to overcome these difficulties.

  17. Microalgae as Sustainable Renewable Energy Feedstock for Biofuel Production

    Science.gov (United States)

    Yusoff, Fatimah Md.; Shariff, M.

    2015-01-01

    The world energy crisis and increased greenhouse gas emissions have driven the search for alternative and environmentally friendly renewable energy sources. According to life cycle analysis, microalgae biofuel is identified as one of the major renewable energy sources for sustainable development, with potential to replace the fossil-based fuels. Microalgae biofuel was devoid of the major drawbacks associated with oil crops and lignocelluloses-based biofuels. Algae-based biofuels are technically and economically viable and cost competitive, require no additional lands, require minimal water use, and mitigate atmospheric CO2. However, commercial production of microalgae biodiesel is still not feasible due to the low biomass concentration and costly downstream processes. The viability of microalgae biodiesel production can be achieved by designing advanced photobioreactors, developing low cost technologies for biomass harvesting, drying, and oil extraction. Commercial production can also be accomplished by improving the genetic engineering strategies to control environmental stress conditions and by engineering metabolic pathways for high lipid production. In addition, new emerging technologies such as algal-bacterial interactions for enhancement of microalgae growth and lipid production are also explored. This review focuses mainly on the problems encountered in the commercial production of microalgae biofuels and the possible techniques to overcome these difficulties. PMID:25874216

  18. TECHNOLOGICAL APPLICATION OF MICROALGAE IN POWER INDUSTRY AND ENVIRONMENTAL PROTECTION

    Directory of Open Access Journals (Sweden)

    Ilmutdin M. Abdulagatov

    2018-01-01

    Full Text Available Abstract. Aim. The aim of the study is to show the possibility and efficiency of large-scale industrial production of microalgae in the Republic of Dagestan for the development of agriculture (feed for animals and poultry and other technological applications in the food and pharmaceutical industries for the production of algalin flour (eco bread, polyunsaturated fatty acids (omega-3, omega-6 physiologically necessary for humans, biologically active substances (astaxanthin, phycocyanin, new-generation antibiotics, biofuels and other high added value biotechnological products. The problems of using microalgae for bioremediation of the environment, in particular, purification of geothermal waters from phenols before discharging into the sewage system are considered. Methods. Microalgae are grown in closed and open type plants. Valuable algae components can be extracted using supercritical fluid technology of continuous action. Results. We give a comparative evaluation of the efficiency of using microalgae as a biological raw material in comparison with traditionally used oilseeds. Conclusion. For Dagestan, located on the shore of the Caspian Sea, with its warm climate and an abundance of solar and geothermal energy, the development of this technology is a task of great economic importance. The advantages of microalgae technologies are the basis for the creation of large-scale production of microalgae in southern Russia. Biotechnology in Dagestan can become not only profitable, but also a high-tech and innovative industry.

  19. Bioelectricity Production from Microalgae-Microbial Fuel Cell Technology (MMFC

    Directory of Open Access Journals (Sweden)

    da Costa Carlito

    2018-01-01

    Full Text Available Microbial fuel cell is an ecological innovative technology producing bioelectricity by utilizing microbes activity. Substituent energy is produced by changing the chemical energy to electrical energy through the catalytic reaction of microorganism. The research aims to find out the potency of bioelectricity produced by microalgae microbial fuel cell technology by utilizing the combination of tapioca wastewater and microalgae cultivation. This research is conducted through the ingredients preparation stage – microalgae culture, wastewater characterization, membrane and graphite activation, and the providing of other supporting equipment. The next stage is the MMFC arrangement, while the last one is bioelectricity measurement. The result of optimal bioelectricity production on the comparison of electrode 2 : 2, the power density is 44,33 mW/m2 on day 6, meanwhile, on that of 1 : 1, 20,18 mW/m2 power density on day 1 is obtained. It shows that bioelectricity can be produced from the combination of tapioca wastewater and microalgae culture through the microalgae-microbial fuel cell (MMFC technology.This research is expected to be a reference for the next research particularly the one that observes the utilizing of microalgae as the part of new and renewable energy sources.

  20. Phycoremediation as a potential water decontamination method

    International Nuclear Information System (INIS)

    Tatarova, D.; Galanda, D.; Kuruc, J.

    2017-01-01

    In experiments, we focused on the determination of the phycoremediation potential of Chlamydomonas reinhardtii and Scenedesmus obliquus in targeted contaminated aqueous solutions containing radioisotopes 137 Cs and 6 0Co. Microalgae were selected based on their high bioremediation capability. Phycoremediation potential was determined by monitoring the effect of different pH values between pH 2 to pH 9 as well as by monitoring the decrease in activity of the solution over time. Cultivation of microalgae took place in 12 h/12 h light/dark light mode in blue and red light, which promotes plant growth at room temperature. In order to determine the micro-sorption capacity, a method was used to determine the concentration of microns using a Buerker cell in parallel with the spectrophotometric method. (authors)

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Aquatic fate of synfuel residuals: bioaccumulation of aniline and phenol by the freshwater phytoplankter Scenedesmus quadricauda

    International Nuclear Information System (INIS)

    Hardy, J.T.; Dauble, D.D.; Felice, L.J.

    1985-01-01

    Coal liquefaction compounds could, through accidental release, enter aquatic environments. Experiments were conducted to determine the kinetics, degree of bioconcentration and stability of two of these compounds at the first level of aquatic food web. The authors exposed the freshwater phytoplankter Scenedesmus quadricauda to sublethal concentrations of 14 C-labeled phenol and aniline. Both accumulation and elimination occurred within a few hours and followed hyperbolic kinetics. Results indicate that substantial quantities of accumulated compounds remain as the parent compound (22% for phenol and 52% for aniline) for up to 24 h and could be available to animals higher in the food web. Bioconcentration factors were 3.5 for phenol and 91 for aniline. 24 references, 2 figures, 1 table

  3. Radiophotosynthesis of some 14C-labelled amino acids using the unicellular green alga Scenedesmus acutus

    International Nuclear Information System (INIS)

    Barakat, M.F.; Farag, A.N.; Ragab, M.T.; El-Fouly, M.M.; El-Baz, F.K.

    1990-01-01

    Radiophotosynthesis has been carried out using the unicellular green algea Scenedesmus acutus grown, as a substrate for preparing some carbon-14 labelled amino acids. Gaseous 14 CO 2 , in an air tight photosynthesis chamber or NaH 14 CO 3 solution, in an ordinary phtosynthesis chamber, were used as radioactive carbon sources. The yields, radiochemical yields and specific activities of the formed radioactive products are reported in both cases. The results obtained clearly showed the advantages of usingthe NaH 14 CO 3 method. In that case the process was by far less tedious. Moreover, the chemical and radiochemical yields of the formed amino acids were relatively much more higher than the values obtained on using 14 CO 2 in the tight photosynthesis chamber. (orig.) [de

  4. Predictive modeling studies for the ecotoxicity of ionic liquids towards the green algae Scenedesmus vacuolatus.

    Science.gov (United States)

    Das, Rudra Narayan; Roy, Kunal

    2014-06-01

    Hazardous potential of ionic liquids is becoming an issue of high concern with increasing application of these compounds in various industrial processes. Predictive toxicological modeling on ionic liquids provides a rational assessment strategy and aids in developing suitable guidance for designing novel analogues. The present study attempts to explore the chemical features of ionic liquids responsible for their ecotoxicity towards the green algae Scenedesmus vacuolatus by developing mathematical models using extended topochemical atom (ETA) indices along with other categories of chemical descriptors. The entire study has been conducted with reference to the OECD guidelines for QSAR model development using predictive classification and regression modeling strategies. The best models from both the analyses showed that ecotoxicity of ionic liquids can be decreased by reducing chain length of cationic substituents and increasing hydrogen bond donor feature in cations, and replacing bulky unsaturated anions with simple saturated moiety having less lipophilic heteroatoms. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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. Neutral lipid accumulation at elevated temperature in conditional mutants of two microalgae species

    DEFF Research Database (Denmark)

    Yao, Shuo; Brandt, Anders Bøving; Egsgaard, Helge

    2012-01-01

    Triacylglycerols, an energy storage compound in microalgae, are known to be accumulated after nitrogen starvation of microalgae cells. Microalgae could be of importance for future biodiesel production due to their fast growth rate and high oil content. In collections of temperature sensitive...... accumulation in microalgae and suggest possibilities for biodiesel production by specific induction of lipid accumulation in miroalgal cultures by cell-cycle inhibition....

  7. Investigation of Inonotus obliquus (Pers. Pil. Extracts and Melanins after RF-plasma Treatment of Raw Material

    Directory of Open Access Journals (Sweden)

    O.Yu. Kuznetsova

    2016-03-01

    Full Text Available High-frequency capacitive discharge (RF plasma at low pressure was used as preliminary stage for the intensification of extraction from natural medicinal raw material. RF-plasma treatment was carried out in two modes differed by the nature of plasma-forming gas. Chaga (Inonotus obliquus (Pers. Pil. known as the birch mushroom was selected as a perspective source of raw material. Extraction was carried out in two ways – remaceration and maceration. The analy-sis of chaga extracts and melanins was performed using traditional techniques including determination of physical and chemical, antioxidant and spectral characteristics. The obtained extracts and melanins were compared to the control samples and literature data. RF-plasma treatment of medicinal raw material increased the yield of extractive substances, in particular of the main active component of chaga – melanin. The antioxidant activity of chaga extracts grew, while for melanins it remained at the level similar to that of control samples. The IR spectral characteristics of the studied chaga melanins are similar and agree well with the literature data. Insignificant deviations in the position and intensity of absorption strips were observed for the samples after RF treatment. IR spectra of the studied chaga melanins are similar to those for mushroom melanins, thereby confirming the similarity in their nature. RF-plasma treatment of chaga medicinal raw materials allows to modify them partially. The structural and mechanical properties of melanins modified by RF plasma remain the same.

  8. The anterior glenohumeral joint capsule: macroscopic and MRI anatomy of the fasciculus obliquus or so-called ligamentum glenohumerale spirale

    Energy Technology Data Exchange (ETDEWEB)

    Merila, M.; Eller, A.; Haviko, T. [Department of Orthopaedics, Clinic of Traumatology and Orthopaedics, University of Tartu, Puusepa 8, 51014, Tartu (Estonia); Leibecke, T.; Gehl, H.B. [Institute of Diagnostic Radiology, University of Luebeck, Ratzeburger Allee 160, 23538, Luebeck (Germany); Busch, L.C. [Institute of Anatomy, University of Luebeck, Ratzeburger Allee 160, 23538, Luebeck (Germany); Russlies, M. [Clinic of Orthopaedics, University of Luebeck, Ratzeburger Allee 160, 23538, Luebeck (Germany); Kolts, I. [Institute of Anatomy, University of Tartu, Ravila 19, Biomedicum, 50411, Tartu (Estonia)

    2004-08-01

    The purpose of this study was to demonstrate the macroscopic and MRI anatomy of the fasciculus obliquus, otherwise known as the ligamentum glenohumerale spirale or spiral GHL of the anterior shoulder joint capsule. Conventional and MR arthrography (1.5-T device Somatom Symphony, Siemens with shoulder coil) images in standard planes were compared with gross anatomic dissection findings in six fresh shoulder specimens from three cadavers. The MR imaging protocol included T1, PD and DESS 3D WI sequences. The macroscopically recognisable band - the spiral GHL - was identified by anatomic dissection and MRI in all the specimens. It was best visualised by MR arthrography on axial and oblique sagittal planes (T1; PD WI) and appeared as a low signal intensity stripe within the superficial layer of the anterior joint capsule. The absence of the variable middle glenohumeral ligament did not influence the anatomic properties and the MR imaging of the spiral GHL. Diagnostic visualisation of the normal anatomic structures is a prerequisite to distinguish between normal and pathologic conditions. Anatomy of the spiral GHL can be used by radiologists for more detailed interpretation of the anterior shoulder joint capsule ligaments on MR images. (orig.)

  9. Benefits of Microalgae for Human Space Exploration

    Science.gov (United States)

    Verrecchia, Angelique; Bebout, Brad M.; Murphy, Thomas

    2015-01-01

    Algae have long been known to offer a number of benefits to support long duration human space exploration. Algae contain proteins, essential amino acids, vitamins, and lipids needed for human consumption, and can be produced using waste streams, while consuming carbon dioxide, and producing oxygen. In comparison with higher plants, algae have higher growth rates, fewer environmental requirements, produce far less "waste" tissue, and are resistant to digestion and/or biodegradation. As an additional benefit, algae produce many components (fatty acids, H2, etc.) which are useful as biofuels. On Earth, micro-algae survive in many harsh environments including low humidity, extremes in temperature, pH, and as well as high salinity and solar radiation. Algae have been shown to survive inmicro-gravity, and can adapt to high and low light intensity while retaining their ability to perform nitrogen fixation and photosynthesis. Studies have demonstrated that some algae are resistant to the space radiation environment, including solar ultraviolet radiation. It remains to be experimentally demonstrated, however, that an algal-based system could fulfil the requirements for a space-based Bioregenerative Life Support System (BLSS) under comparable spaceflight power, mass, and environmental constraints. Two specific challenges facing algae cultivation in space are that (i) conventional growth platforms require large masses of water, which in turn require a large amount of propulsion fuel, and (ii) most nutrient delivery mechanisms (predominantly bubbling) are dependent on gravity. To address these challenges, we have constructed a low water biofilm based bioreactor whose operation is enabled by capillary forces. Preliminary characterization of this Surface Adhering BioReactor (SABR) suggests that it can serve as a platform for cultivating algae in space which requires about 10 times less mass than conventional reactors without sacrificing growth rate. Further work is necessary to

  10. Molasses wastewater treatment and lipid production at low temperature conditions by a microalgal mutant Scenedesmus sp. Z-4

    OpenAIRE

    Ma, Chao; Wen, Hanquan; Xing, Defeng; Pei, Xuanyuan; Zhu, Jiani; Ren, Nanqi; Liu, Bingfeng

    2017-01-01

    Background Simultaneous wastewater treatment and lipid production by oleaginous microalgae show great potential to alleviate energy shortage and environmental pollution, because they exhibit tremendous advantages over traditional activated sludge. Currently, most research on wastewater treatment by microalgal are carried out at optimized temperature conditions (25?35??C), but no information about simultaneous wastewater treatment and lipid production by microalgae at low temperatures has been...

  11. Extracellular Metabolites from Industrial Microalgae and Their Biotechnological Potential

    Directory of Open Access Journals (Sweden)

    Lu Liu

    2016-10-01

    Full Text Available Industrial microalgae, as a big family of promising producers of renewable biomass feedstock, have been commercially exploited for functional food, living feed and feed additives, high-value chemicals in nutraceuticals, cosmeceuticals, and chemical reagents. Recently, microalgae have also been considered as a group that might play an important role in biofuel development and environmental protection. Almost all current products of industrial microalgae are derived from their biomass; however, large amounts of spent cell-free media are available from mass cultivation that is mostly unexploited. In this contribution we discuss that these media, which may contain a remarkable diversity of bioactive substances are worthy to be recovered for further use. Obviously, the extracellular metabolites from industrial microalgae have long been neglected in the development of production methods for valuable metabolites. With the advances in the last ten years, more and more structures and properties from extracellular metabolites have been identified, and the potential utilization over wide fields is attracting attention. Some of these extracellular metabolites can be potentially used as drugs, antioxidants, growth regulators or metal chelators. The purpose of this review is to provide an overview of the known extracellular metabolites from industrial microalgae which might be of commercial interest. The attention mainly focuses on the reports of extracellular bioactive metabolites and their potential application in biotechnology.

  12. BIOREMOVAL OF LEAD IN INDUSTRIAL WASTEWATER BY MICROALGAE

    Directory of Open Access Journals (Sweden)

    M. RANITHA

    2016-07-01

    Full Text Available The removal of heavy metals from our environment especially wastewater is now shifting from the use of conventional removal method such as chemical precipitation, coagulation and membrane filtration to the use of bioremoval method. The presence of heavy metals in the environment is of major concern because of their toxicity, bioaccumulating tendency, and threat to human life and the environment. In recent years, many low cost sorbents such as microalgae, fungi bacteria and lignocellulosic agricultural by-products have been investigated for their biosorption capacity towards heavy metals. In this project, the focus is on bioremoval of heavy metals in wastewater using marine microalgae. The study will be emphasize on the efficiency of two marine microalgae named Nannochloropsis oculata and Tetraselmis chuii in treating the Lead (Pb content in industrial wasterwater. An experiment on the effect of various Pb concentration (10/20/40/60/80/100mg/L towards the microalgae has been studied. The obtained result showed that the content of chlorophyll-A in the microalgae sample, after 7 days of exposures to Pb, decreased as the Pb concentration increased. Besides that, Tetraselmis chuii was found to be more sensitive compared to Nannochloropsis oculata where both were able to tolerate the Pb concentration of up to only 20mg/L and 60mg/L, respectively.

  13. Monitoring Growth and Lipid Production of Some Egyptian Microalgae

    International Nuclear Information System (INIS)

    El-Baghdady, K.Z.; Zakaria, A.E.; Mousa, L.A.; Sadek, H.N.; Abd El Fatah, H.M.

    2016-01-01

    Microalgae bio diesel is a green and renewable energy resource. This study aims to examine growth and lipid production by various isolates of icroalgae using different growth media and lipid extraction techniques. Ten microalgae isolates were isolated from different samples collected from Egypt. The purified isolates were identified microscopically as: Lyngbya confervoides, Phormidium bohneri, Oscillatoria pseudogeminata, Amorphonostoc sp., Nostoc paludosum, Anabaena sphaerica related to cyanobacteria (blue green algae) and Chlorella vulgaris, Chlorella ellipsoidea, Scened esmusacutus acutus, Chlamydomonas globose related to green algae. These organisms were cultivated on two media: Bold's Basal Medium(BBM medium) and Blue Green Medium (BG-11 medium) to examine the favorite medium which supports the growth of each isolate In order to examine lipid production potentials by cyanobacterial isolates and green microalgae, two solvent systems were applied for lipid extraction, the first was (Chloroform - methanol 1:1 ) and the second was (Hexane-ethanol 1:1). Chlorella vulgaris and Anabaena sphaerica were selected as models of green microalgae and cyanobacteria espectively. Hexane-ethanol solvent system revealed higher lipid extraction capacity as compared to Chloroform- methanol system. A comparison between ten organisms for lipid production was carried out by the selected solvent mixture. The percentages of lipid to dry weight produced by Oscillatoria pseudogeminata and Chlamydomonas globose were 19.8% and14 .6% respectively recording the highest lipid to dry weight percentage. They can be considered as a promising lipid producing microalgae

  14. Influence of Microalgae onto submerged surfaces on Fouling

    Science.gov (United States)

    Kong, M.; Eom, C.; Yoon, B.; Yoon, H.; Kim, B.; Chung, K.

    2012-12-01

    Lots of algae together with organic matter deposited on the submerged surface can be easily observed occurring in the shallower water along the coast. This is mainly because only those organisms with the ability to adapt to the new situations created by man can firmly adhere enough to avoid being washed off. Chemical and microbiological characteristics of the fouling microalgae developed on various surfaces in contact with the seawater were made. The microbial compositions of the microalgae formed on the submerged surfaces were tested for. The quantities of the diverse microalgae in the samples developed on the prohibiting submerged surface were larger when there was no concern about materials for special selection for fouling. To confirm formation of microalgae on adsorbents was done SEM-EDS (Scanning Electron Microscope-Spectrometer) analysis. Microbial identified using optical microscope. In addition to, we quantified attaching microalgae as pass time. Experiment results, ten species which are Nitzshhia sp., Eucampia sp., Coscinodiscus sp., Licmophora sp., Rhizosolenia sp., Cylindrotheca sp., Striateela sp., Thalassionema sp., Guinardia sp., and Helicostomella sp. discovered to reservoir formed biofouling. They showed the important role microbial activity in fouling and corrosion of the surfaces in contact with the any seawater.

  15. Fuels from microalgae: Technology status, potential, and research requirements

    Energy Technology Data Exchange (ETDEWEB)

    Neenan, B.; Feinberg, D.; Hill, A.; McIntosh, R.; Terry, K.

    1986-08-01

    Although numerous options for the production of fuels from microalgae have been proposed, our analysis indicates that only two qualify for extensive development - gasoline and ester fuel. In developing the comparisons that support this conclusion, we have identified the major areas of microalgae production and processing that require extensive development. Technology success requires developing and testing processes that fully utilize the polar and nonpolar lipids produced by microalgae. Process designs used in these analyses were derived from fragmented, preliminary laboratory data. These results must be substantiated and integrated processes proposed, tested, and refined to be able to evaluate the commercial feasibility from microalgae. The production of algal feedstocks for processing to gasoline or ester fuel requires algae of high productivity and high lipid content that efficiently utilize saline waters. Species screening and development suggest that algae can achieve required standards taken individually, but algae that can meet the integrated requirements still elude researchers. Effective development of fuels from microalgae technology requires that R and D be directed toward meeting the integrated standards set out in the analysis. As technology analysts, it is inappropriate for us to dictate how the R and D effort should proceed to meet these standards. We end our role by noting that alternative approaches to meeting the feasibility targets have been identified, and it is now the task of program managers and scientists to choose the appropriate approach to assure the greatest likelihood of realizing a commercially viable technology. 70 refs., 39 figs., 35 tabs.

  16. Nutrient and media recycling in heterotrophic microalgae cultures.

    Science.gov (United States)

    Lowrey, Joshua; Armenta, Roberto E; Brooks, Marianne S

    2016-02-01

    In order for microalgae-based processes to reach commercial production for biofuels and high-value products such as omega-3 fatty acids, it is necessary that economic feasibility be demonstrated at the industrial scale. Therefore, process optimization is critical to ensure that the maximum yield can be achieved from the most efficient use of resources. This is particularly true for processes involving heterotrophic microalgae, which have not been studied as extensively as phototrophic microalgae. An area that has received significant conceptual praise, but little experimental validation, is that of nutrient recycling, where the waste materials from prior cultures and post-lipid extraction are reused for secondary fermentations. While the concept is very simple and could result in significant economic and environmental benefits, there are some underlying challenges that must be overcome before adoption of nutrient recycling is viable at commercial scale. Even more, adapting nutrient recycling for optimized heterotrophic cultures presents some added challenges that must be identified and addressed that have been largely unexplored to date. These challenges center on carbon and nitrogen recycling and the implications of using waste materials in conjunction with virgin nutrients for secondary cultures. The aim of this review is to provide a foundation for further understanding of nutrient recycling for microalgae cultivation. As such, we outline the current state of technology and practical challenges associated with nutrient recycling for heterotrophic microalgae on an industrial scale and give recommendations for future work.

  17. Nitrogen Removal from Landfill Leachate by Microalgae

    Science.gov (United States)

    Pereira, Sérgio F. L.; Gonçalves, Ana L.; Moreira, Francisca C.; Silva, Tânia F. C. V.; Vilar, Vítor J. P.; Pires, José C. M.

    2016-01-01

    Landfill leachates result from the degradation of solid residues in sanitary landfills, thus presenting a high variability in terms of composition. Normally, these effluents are characterized by high ammoniacal-nitrogen (N–NH4+) concentrations, high chemical oxygen demands and low phosphorus concentrations. The development of effective treatment strategies becomes difficult, posing a serious problem to the environment. Phycoremediation appears to be a suitable alternative for the treatment of landfill leachates. In this study, the potential of Chlorella vulgaris for biomass production and nutrients (mainly nitrogen and phosphorus) removal from different compositions of a landfill leachate was evaluated. Since microalgae also require phosphorus for their growth, different loads of this nutrient were evaluated, giving the following N:P ratios: 12:1, 23:1 and 35:1. The results have shown that C. vulgaris was able to grow in the different leachate compositions assessed. However, microalgal growth was higher in the cultures presenting the lowest N–NH4+ concentration. In terms of nutrients uptake, an effective removal of N–NH4+ and phosphorus was observed in all the experiments, especially in those supplied with phosphorus. Nevertheless, N–NO3− removal was considered almost negligible. These promising results constitute important findings in the development of a bioremediation technology for the treatment of landfill leachates. PMID:27869676

  18. Microalgae culture collection, 1986-1987

    Energy Technology Data Exchange (ETDEWEB)

    Barclay, W.; Johansen, J.; Chelf, P.; Nagle, N.; Roessler, P.; Lemke, P.

    1986-12-01

    The SERI Microalgae Culture Collection provides a repository for strains identified or developed for mass culture biomass production and makes these strains readily available to the research community. The strains in the collection have been selected for their potential in biomass fuel applications, and many produce significant quantities of cellular storage lipids. All of the newly added strains have been recently isolated by SERI and its subcontractors in organized screening programs. Many have been tested in outdoor mass culture systems, and several have demonstrated excellent performance as biomass producers. The strains added to the collection this year have been isolated from inland saline waters and marine waters. We believe that the strains in this collection can provide a source of extremely useful organisms, both for laboratory experimentation and for mass culture research. Most of the strains are currently nonaxenic. Again this year, cultures will be shipped free of charge to interested researchers. An important function of the culture collection catalog, in addition to listing the available strains, is to provide culture and performance data for each of the organisms. By collecting a summary of the requirements and characteristics of these organisms, we hope to allow requestors of cultures to begin productive research with a minimum of preliminary work on culture techniques.

  19. Microalgae Culture Collection, 1985-1986

    Energy Technology Data Exchange (ETDEWEB)

    1986-01-01

    The SERI Microalgae Culture Collection was established in support of the US Department of Energy's Biofuels Program to provide a repository for strains identified or developed for mass culture biomass production and to make these strains readily available to the research community. The strains in the collection have been selected for their potential in biomass fuel applications, and many produce significant quantities of cellular storage lipids. The Culture Collection Catalog lists 20 strains of ten species. Many have been tested in outdoor mass culture systems, and several have demonstrated excellent performance as biomass producers, with yields of up to 40 grams of organic matter per square meter per day. The majority of strains added to the collection this year have been isolated from inland saline waters, although marine species are included as well. We believe that the strains in this collection can provide a source of extremely useful organisms, both for laboratory experimentation and for mass culture research. 98 refs., 31 figs., 52 tabs.

  20. Antioxidant activity of the microalga Spirulina maxima

    Directory of Open Access Journals (Sweden)

    M.S. Miranda

    1998-08-01

    Full Text Available Spirulina maxima, which is used as a food additive, is a microalga rich in protein and other essential nutrients. Spirulina contains phenolic acids, tocopherols and ß-carotene which are known to exhibit antioxidant properties. The aim of the present study was to evaluate the antioxidant capacity of a Spirulina extract. The antioxidant activity of a methanolic extract of Spirulina was determined in vitro and in vivo. The in vitro antioxidant capacity was tested on a brain homogenate incubated with and without the extract at 37oC. The IC50 (concentration which causes a 50% reduction of oxidation of the extract in this system was 0.18 mg/ml. The in vivo antioxidant capacity was evaluated in plasma and liver of animals receiving a daily dose of 5 mg for 2 and 7 weeks. Plasma antioxidant capacity was measured in brain homogenate incubated for 1 h at 37oC. The production of oxidized compounds in liver after 2 h of incubation at 37oC was measured in terms of thiobarbituric acid reactant substances (TBARS in control and experimental groups. Upon treatment, the antioxidant capacity of plasma was 71% for the experimental group and 54% for the control group. Data from liver spontaneous peroxidation studies were not significantly different between groups. The amounts of phenolic acids, a-tocopherol and ß-carotene were determined in Spirulina extracts. The results obtained indicate that Spirulina provides some antioxidant protection for both in vitro and in vivo systems.

  1. Growth of microalgae in autotrophic stationary systems

    Directory of Open Access Journals (Sweden)

    Paulo Cunha

    2008-06-01

    Full Text Available In this paper we evaluate the growth of nine marine microalgae species (Nannochloropsis oculata, Thalassiosira pseudonana, Phaeodactylum tricornutum, Isochrysis galbana, Tetraselmis suecica, Tetraselmis chuii, Chaetoceros muelleri, Thalassiosira fluviatilis and Isochrysis sp. and one freshwater species (Chlorella vulgaris under stationary autotrophy conditions, using erlenmeyers fl asks with 800mL of culture medium exposed to constant light intensities providing a photon flux density of about 150μmol.m-2.s-1 and 25±2oC temperature and constant air flow. The experiment was carried out in a controlled environment considering a block delineating randomized over time with three replicates. The Nannochloropsis oculata showed the highest value of maximum cellular density, but with a longer period of time and a lower growth rate. This was probably due to its tiny cell size, demanding a large number of cells per volume to attain its optimum conditions for light, nutrients, water and atmospheric carbon dioxide. In addition, in spite of showing one of the lowest values of maximum cellular density, Thalassiosira fluviatilis was the species that reached its maximum in a short period of time at the highest growth rate. Chlorella vulgaris was the only freshwater species tested and it showed the poorest performance for all the variables analyzed in the current study.

  2. Gold nanoparticles produced in a microalga

    International Nuclear Information System (INIS)

    Luangpipat, Tiyaporn; Beattie, Isabel R.; Chisti, Yusuf; Haverkamp, Richard G.

    2011-01-01

    An efficient biological route to production of gold nanoparticles which allows the nanoparticles to be easily recovered remains elusive. Live cells of the green microalga Chlorella vulgaris were incubated with a solution of gold chloride and harvested by centrifugation. Nanoparticles inside intact cells were identified by transmission electron microscopy and confirmed to be metallic gold by synchrotron based X-ray powder diffraction and X-ray absorption spectroscopy. These intracellular gold nanoparticles were 40–60 nm in diameter. At a concentration of 1.4% Au in the alga, a better than 97% recovery of the gold from solution was achieved. A maximum of 4.2% Au in the alga was obtained. Exposure of C. vulgaris to solutions containing dissolved salts of palladium, ruthenium, and rhodium also resulted in the production of the corresponding nanoparticles within the cells. These were surmised to be also metallic, but were produced at a much lower intracellular concentration than achieved with gold. Iridium was apparently toxic to the alga. No nanoparticles were observed using platinum solutions. C. vulgaris provides a possible route to large scale production of gold nanoparticles.

  3. Microalgae as bioreactors for bioplastic production

    Directory of Open Access Journals (Sweden)

    Steinbüchel Alexander

    2011-10-01

    Full Text Available Abstract Background Poly-3-hydroxybutyrate (PHB is a polyester with thermoplastic properties that is naturally occurring and produced by such bacteria as Ralstonia eutropha H16 and Bacillus megaterium. In contrast to currently utilized plastics and most synthetic polymers, PHB is biodegradable, and its production is not dependent on fossil resources making this bioplastic interesting for various industrial applications. Results In this study, we report on introducing the bacterial PHB pathway of R. eutropha H16 into the diatom Phaeodactylum tricornutum, thereby demonstrating for the first time that PHB production is feasible in a microalgal system. Expression of the bacterial enzymes was sufficient to result in PHB levels of up to 10.6% of algal dry weight. The bioplastic accumulated in granule-like structures in the cytosol of the cells, as shown by light and electron microscopy. Conclusions Our studies demonstrate the great potential of microalgae like the diatom P. tricornutum to serve as solar-powered expression factories and reveal great advantages compared to plant based production systems.

  4. A Holistic Approach to Managing Microalgae for Biofuel Applications

    Directory of Open Access Journals (Sweden)

    Pau Loke Show

    2017-01-01

    Full Text Available Microalgae contribute up to 60% of the oxygen content in the Earth’s atmosphere by absorbing carbon dioxide and releasing oxygen during photosynthesis. Microalgae are abundantly available in the natural environment, thanks to their ability to survive and grow rapidly under harsh and inhospitable conditions. Microalgal cultivation is environmentally friendly because the microalgal biomass can be utilized for the productions of biofuels, food and feed supplements, pharmaceuticals, nutraceuticals, and cosmetics. The cultivation of microalgal also can complement approaches like carbon dioxide sequestration and bioremediation of wastewaters, thereby addressing the serious environmental concerns. This review focuses on the factors affecting microalgal cultures, techniques adapted to obtain high-density microalgal cultures in photobioreactors, and the conversion of microalgal biomass into biofuels. The applications of microalgae in carbon dioxide sequestration and phycoremediation of wastewater are also discussed.

  5. Bioactivity and Applications of Sulphated Polysaccharides from Marine Microalgae

    Directory of Open Access Journals (Sweden)

    Rui Manuel Santos Costa de Morais

    2013-01-01

    Full Text Available Marine microalgae have been used for a long time as food for humans, such as Arthrospira (formerly, Spirulina, and for animals in aquaculture. The biomass of these microalgae and the compounds they produce have been shown to possess several biological applications with numerous health benefits. The present review puts up-to-date the research on the biological activities and applications of polysaccharides, active biocompounds synthesized by marine unicellular algae, which are, most of the times, released into the surrounding medium (exo- or extracellular polysaccharides, EPS. It goes through the most studied activities of sulphated polysaccharides (sPS or their derivatives, but also highlights lesser known applications as hypolipidaemic or hypoglycaemic, or as biolubricant agents and drag-reducers. Therefore, the great potentials of sPS from marine microalgae to be used as nutraceuticals, therapeutic agents, cosmetics, or in other areas, such as engineering, are approached in this review.

  6. Multi-Product Microalgae Biorefineries: From Concept Towards Reality.

    Science.gov (United States)

    't Lam, G P; Vermuë, M H; Eppink, M H M; Wijffels, R H; van den Berg, C

    2018-02-01

    Although microalgae are a promising biobased feedstock, industrial scale production is still far off. To enhance the economic viability of large-scale microalgae processes, all biomass components need to be valorized, requiring a multi-product biorefinery. However, this concept is still too expensive. Typically, downstream processing of industrial biotechnological bulk products accounts for 20-40% of the total production costs, while for a microalgae multi-product biorefinery the costs are substantially higher (50-60%). These costs are high due to the lack of appropriate and mild technologies to access the different product fractions such as proteins, carbohydrates, and lipids. To reduce the costs, simplified processes need to be developed for the main unit operations including harvesting, cell disruption, extraction, and possibly fractionation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Heterotrophic cultivation of microalgae for pigment production: A review.

    Science.gov (United States)

    Hu, Jianjun; Nagarajan, Dillirani; Zhang, Quanguo; Chang, Jo-Shu; Lee, Duu-Jong

    Pigments (mainly carotenoids) are important nutraceuticals known for their potent anti-oxidant activities and have been used extensively as high end health supplements. Microalgae are the most promising sources of natural carotenoids and are devoid of the toxic effects associated with synthetic derivatives. Compared to photoautotrophic cultivation, heterotrophic cultivation of microalgae in well-controlled bioreactors for pigments production has attracted much attention for commercial applications due to overcoming the difficulties associated with the supply of CO 2 and light, as well as avoiding the contamination problems and land requirements in open autotrophic culture systems. In this review, the heterotrophic metabolic potential of microalgae and their uses in pigment production are comprehensively described. Strategies to enhance pigment production under heterotrophic conditions are critically discussed and the challenges faced in heterotrophic pigment production with possible alternative solutions are presented. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Microalgae Isolation and Selection for Prospective Biodiesel Production

    Directory of Open Access Journals (Sweden)

    Peer M. Schenk

    2012-06-01

    Full Text Available Biodiesel production from microalgae is being widely developed at different scales as a potential source of renewable energy with both economic and environmental benefits. Although many microalgae species have been identified and isolated for lipid production, there is currently no consensus as to which species provide the highest productivity. Different species are expected to function best at different aquatic, geographical and climatic conditions. In addition, other value-added products are now being considered for commercial production which necessitates the selection of the most capable algae strains suitable for multiple-product algae biorefineries. Here we present and review practical issues of several simple and robust methods for microalgae isolation and selection for traits that maybe most relevant for commercial biodiesel production. A combination of conventional and modern techniques is likely to be the most efficient route from isolation to large-scale cultivation.

  9. Cultivation Of Microalgae (Chlorella vulgaris For Biodiesel Production

    Directory of Open Access Journals (Sweden)

    Blinová Lenka

    2015-06-01

    Full Text Available Production of biofuel from renewable sources is considered to be one of the most sustainable alternatives to petroleum sourced fuels. Biofuels are also viable means of environmental and economic sustainability. Biofuels are divided into four generations, depending on the type of biomass used for biofuels production. At present, microalgae are presented as an ideal third generation biofuel feedstock because of their rapid growth rate. They also do not compete with food or feed crops, and can be produced on non-arable land. Cultivation conditions (temperature, pH, light, nutrient quantity and quality, salinity, aerating are the major factors that influence photosynthesis activity and behaviour of the microalgae growth rate. In this paper, we present an overview about the effect of cultivation conditions on microalgae growth.

  10. Microalga propels along vorticity direction in a shear flow

    Science.gov (United States)

    Chengala, Anwar; Hondzo, Miki; Sheng, Jian

    2013-05-01

    Using high-speed digital holographic microscopy and microfluidics, we discover that, when encountering fluid flow shear above a threshold, unicellular green alga Dunaliella primolecta migrates unambiguously in the cross-stream direction that is normal to the plane of shear and coincides with the local fluid flow vorticity. The flow shear drives motile microalgae to collectively migrate in a thin two-dimensional horizontal plane and consequently alters the spatial distribution of microalgal cells within a given suspension. This shear-induced algal migration differs substantially from periodic rotational motion of passive ellipsoids, known as Jeffery orbits, as well as gyrotaxis by bottom-heavy swimming microalgae in a shear flow due to the subtle interplay between torques generated by gravity and viscous shear. Our findings could facilitate mechanistic solutions for modeling planktonic thin layers and sustainable cultivation of microalgae for human nutrition and bioenergy feedstock.

  11. Engineering fatty acid biosynthesis in microalgae for sustainable biodiesel.

    Science.gov (United States)

    Blatti, Jillian L; Michaud, Jennifer; Burkart, Michael D

    2013-06-01

    Microalgae are a promising feedstock for biodiesel and other liquid fuels due to their fast growth rate, high lipid yields, and ability to grow in a broad range of environments. However, many microalgae achieve maximal lipid yields only under stress conditions hindering growth and providing compositions not ideal for biofuel applications. Metabolic engineering of algal fatty acid biosynthesis promises to create strains capable of economically producing fungible and sustainable biofuels. The algal fatty acid biosynthetic pathway has been deduced by homology to bacterial and plant systems, and much of our understanding is gleaned from basic studies in these systems. However, successful engineering of lipid metabolism in algae will necessitate a thorough characterization of the algal fatty acid synthase (FAS) including protein-protein interactions and regulation. This review describes recent efforts to engineer fatty acid biosynthesis toward optimizing microalgae as a biodiesel feedstock. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Thermogravimetric analysis of the gasification of microalgae Chlorella vulgaris.

    Science.gov (United States)

    Figueira, Camila Emilia; Moreira, Paulo Firmino; Giudici, Reinaldo

    2015-12-01

    The gasification of microalgae Chlorella vulgaris under an atmosphere of argon and water vapor was investigated by thermogravimetric analysis. The data were interpreted by using conventional isoconversional methods and also by the independent parallel reaction (IPR) model, in which the degradation is considered to happen individually to each pseudo-component of biomass (lipid, carbohydrate and protein). The IPR model allows obtaining the kinetic parameters of the degradation reaction of each component. Three main stages were observed during the gasification process and the differential thermogravimetric curve was satisfactorily fitted by the IPR model considering three pseudocomponents. The comparison of the activation energy values obtained by the methods and those found in the literature for other microalgae was satisfactory. Quantification of reaction products was performed using online gas chromatography. The major products detected were H2, CO and CH4, indicating the potential for producing fuel gas and syngas from microalgae. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Ultrasonic assisted biodiesel production of microalgae by direct transesterification

    Science.gov (United States)

    Kalsum, Ummu; Mahfud, Mahfud; Roesyadi, Achmad

    2017-03-01

    Microalgae are considered as the third generation source of biofuel and an excellent candidate for biofuel production to replace the fossil energy. The use of ultrasonic in producing biodiesel by direct transesterification of Nannochloropsis occulata using KOH as catalyst and methanol as a solvent was investigated. The following condition were determined as an optimum by experimental evaluates:: 1: 15 microalga to methanol (molar ratio); 3% catalyst concentration at temperature 40°C after 30 minute of ultrasonication. The highest yield of biodiesel produced was 30.3%. The main components of methyl ester from Nannochloropsis occulata were palmitic (C16 :0),, oleic (C18:1), stearic (C18;0), arahidic (C20:0) and myristic (C14:0). This stated that the application of ultrasounic for direct transesterificaiton of microalgae effectively reduced the reaction time compared to the reported values of conventional heating systems.

  14. Microalgae as source of biofuel: technology and prospective

    Science.gov (United States)

    Ferraro, Angelo

    2017-12-01

    Microalgae are autotrophic organisms found in solitary cells or in groups of single cells connected together. Their natural environment are typically freshwater and marine systems. Microalgae produce, via photosynthesis, approximately one-half of oxygen generated on earth while simultaneously consume carbon dioxide (CO2). Among the technologies being examined to produce green fuels (e.g. biodiesel, bioethanol and syngas), microalgae are viewed by many in the scientific community as having the greatest potential to become economically viable fuels. Nevertheless, to reach economic parity with fossil fuels there are still several challenges to be tackle. These include improving harvesting and oil extraction processes as well as increasing biomass productivity and oil content. All of these challenges can be impacted by genetic, molecular, and ultimately synthetic biology techniques.

  15. Advances in Microalgae-Derived Phytosterols for Functional Food and Pharmaceutical Applications.

    Science.gov (United States)

    Luo, Xuan; Su, Peng; Zhang, Wei

    2015-07-09

    Microalgae contain a variety of bioactive lipids with potential applications in aquaculture feed, biofuel, food and pharmaceutical industries. While microalgae-derived polyunsaturated fatty acid (PUFA) and their roles in promoting human health have been extensively studied, other lipid types from this resource, such as phytosterols, have been poorly explored. Phytosterols have been used as additives in many food products such as spread, dairy products and salad dressing. This review focuses on the recent advances in microalgae-derived phytosterols with functional bioactivities and their potential applications in functional food and pharmaceutical industries. It highlights the importance of microalgae-derived lipids other than PUFA for the development of an advanced microalgae industry.

  16. Biogas Production From Cassava Starch Effluent Using Microalgae As Biostabilisator

    Directory of Open Access Journals (Sweden)

    B. Budiyono

    2011-07-01

    Full Text Available The rapid growing of Indonesian population is emerging several critical national issues i.e. energy, food, environmental, water, transportation, as well as law and human right. As an agricultural country, Indonesia has abundant of biomass wastes such as agricultural wastes include the cassava starch wastes. The problem is that the effluent from cassava starch factories is released directly into the river before properly treatment. It has been a great source of pollution and has caused environmental problems to the nearby rural population. The possible alternative to solve the problem is by converting waste to energy biogas in the biodigester. The main problem of the biogas production of cassava starch effluent is acid forming-bacteria quickly produced acid resulting significantly in declining pH below the neutral pH and diminishing growth of methane bacteria. Hence, the only one of the method to cover this problem is by adding microalgae as biostabilisator of pH. Microalgae can also be used as purifier agent to absorb CO2.The general objective of this research project was to develop an integrated process of biogas production and purification from cassava starch effluent by using biostabilisator agent microalgae. This study has been focused on the used of urea, ruminant, yeast, microalgae, the treatment of gelled and ungelled feed for biogas production, pH control during biogas production using buffer Na2CO3, and feeding management in the semi-continuous process of biogas production. The result can be concluded as follows: i The biogas production increased after cassava starch effluent and yeast was added, ii Biogas production with microalgae and cassava starch effluent, yeast, ruminant bacteria, and urea were 726.43 ml/g total solid, iii Biogas production without  microalgae was 189 ml/g total solid.

  17. Advances and perspectives in using microalgae to produce biodiesel

    International Nuclear Information System (INIS)

    Amaro, Helena M.; Guedes, A. Catarina; Malcata, F. Xavier

    2011-01-01

    Carbon-neutral renewable liquid biofuels are needed to displace petroleum-derived transport fuels in the near future - which contribute to global warming and are of a limited availability. A promising alternative is conveyed by microalgae, the oil content of which may exceed 80% (w/w DW ) - as compared with 5% of the best agricultural oil crops. However, current implementation of microalga-based systems has been economically constrained by their still poor volumetric efficiencies - which lead to excessively high costs, as compared with petrofuel prices. Technological improvements of such processes are thus critical - and this will require a multiple approach, both on the biocatalyst and bioreactor levels. Several bottlenecks indeed exist at present that preclude the full industrial exploitation of microalgal cells: the number of species that have been subjected to successful genetic transformation is scarce, which hampers a global understanding (and thus a rational design) of novel blue-biotechnological processes; the mechanisms that control regulation of gene expression are not fully elucidated, as required before effective bioprocesses based on microalgae can be scaled-up; and new molecular biology tools are needed to standardize genetic modifications in microalgae - including efficient nuclear transformation, availability of promoter or selectable marker genes, and stable expression of transgenes. On the other hand, a number of pending technological issues are also present: the relatively low microalga intrinsic lipid productivity; the maximum cell concentration attainable; the efficiency of harvest and sequential recovery of bulk lipids; and the possibility of by-product upgrade. This review briefly covers the state of the art regarding microalgae toward production of biofuels, both from the point of view of the microalgal cell itself and of the supporting bioreactor; and discusses, in a critical manner, current limitations and promising perspectives in this

  18. 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

  19. Terpenes as Green Solvents for Extraction of Oil from Microalgae

    Directory of Open Access Journals (Sweden)

    Celine Dejoye Tanzi

    2012-07-01

    Full Text Available Herein is described a green and original alternative procedure for the extraction of oil from microalgae. Extractions were carried out using terpenes obtained from renewable feedstocks as alternative solvents instead of hazardous petroleum solvents such as n-hexane. The described method is achieved in two steps using Soxhlet extraction followed by the elimination of the solvent from the medium using Clevenger distillation in the second step. Oils extracted from microalgae were compared in terms of qualitative and quantitative determination. No significant difference was obtained between each extract, allowing us to conclude that the proposed method is green, clean and efficient.

  20. Potency of Microalgae as Biodiesel Source in Indonesia

    Directory of Open Access Journals (Sweden)

    H Hadiyanto

    2012-04-01

    Full Text Available Within 20 years, Indonesia should find another energy alternative to substitutecurrent fossil oil. Current use of renewable energy is only 5% and need to be improved up to 17%of our energy mix program. Even though, most of the area in Indonesia is covered by sea, howeverthe utilization of microalgae as biofuel production is still limited. The biodiesel from currentsources (Jatropha, palm oil, and sorghum is still not able to cover all the needs if the fossil oilcannot be explored anymore. In this paper, the potency of microalgae in Indonesia was analysed asthe new potential of energy (biodiesel sources.

  1. Potency of Microalgae as Biodiesel Source in Indonesia

    Directory of Open Access Journals (Sweden)

    H Hadiyanto

    2012-02-01

    Full Text Available Within 20 years, Indonesia should find another energy alternative to substitute current fossil oil. Current use of renewable energy is only 5% and need to be improved up to 17% of our energy mix program. Even though, most of the area in Indonesia is covered by sea, however the utilization of microalgae as biofuel production is still limited. The biodiesel from current sources (Jatropha, palm oil, and sorghum is still not able to cover all the needs if the fossil oil cannot be explored anymore. In this paper, the potency of microalgae in Indonesia was analysed as the new potential of energy (biodiesel sources.

  2. Microalgae: An alternative as sustainable source of biofuels?

    International Nuclear Information System (INIS)

    Amaro, Helena M.; Macedo, Ângela C.; Malcata, F. Xavier

    2012-01-01

    In recent decades, the world has been confronted with an energy crisis associated with irreversible depletion of traditional sources of fossil fuels, coupled with atmospheric accumulation of greenhouse gases that cause global warming. The urgent need to replace traditional fuels led to emergence of biodiesel and biohydrogen as interesting alternatives, both of which can be obtained via microalga-mediated routes. Microalgae are ubiquitous eukaryotic microorganisms, characterized by a remarkable metabolic plasticity. Their oil productivities are much higher than those of higher terrestrial plants, and they do not require high quality agricultural land. Microalgae may indeed be cultivated in brackish and wastewaters that provide suitable nutrients (e.g. NH 4 + ,NO 3 − andPO 4 3− ), at the expense of only sunlight and atmospheric CO 2 . On the other hand, metabolic engineering permits release of molecular hydrogen also via photosynthetic routes, which will easily be converted to electricity in fuel cells or mechanical power in explosion engines, with only water vapor as exhaust product in both cases. However, large-scale implementation of microalga-based systems to manufacture biodiesel and biohydrogen has been economically constrained by their still poor volumetric efficiencies, which imply excessively high costs when compared with current petrofuel prices. Technological improvements are accordingly critical, both on the biocatalyst and the bioreactor levels. The current bottlenecks that have apparently precluded full industrial exploitation of microalgae cells are critically discussed here, viz. those derived from the scarce knowledge on the mechanisms that control regulation of gene expression, the reduced number of species subjected to successful genetic transformation, the relatively low cell density attainable, the poor efficiency in harvesting, and the difficulties in light capture and use. Therefore, this paper provides an overview of the feasibility of

  3. Nanosilver microalgae biosynthesis: cell appearance based on SEM and EDX methods

    Science.gov (United States)

    Pancasakti Kusumaningrum, Hermin; Zainuri, Muhammad; Marhaendrajaya, Indras; Subagio, Agus

    2018-05-01

    Microbial contamination has caused public health problems in the world population. This problem has spurred the development of methods to overcome and prevent microbial invasion. The extensive use of antibiotics has facilitated the continued emergence and spread of resistant organisms. Synthesized of silver nanoparticle (AgNPs) on microalgae Chlorella pyrenoidosa offer environmentally safe antimicrobial agent. The present study is focused on the biosynthesis of AgNPs using microalgae C. pyrenoidosa. The research methods was conducted by insertion of nanosilver particle into microalgae cells with and without agitation to speed up the process of formation nanosilver microalgae. The formation of microalgae SNP was analyzes by UV-Vis spectrophotometer, Scanning Electron Micrograph (SEM) and Energy-dispersive X-ray spectroscopy (EDX) methods. The research result showed that nanosilver microalgae biosynthesis using the agitation treatment was exhibited better performance in particle insertion and cell stability, comparing with no agitation treatment. However, synthesis of nanosilver microalgae tend to reduce the cell size.

  4. Wet torrefaction of microalga Chlorella vulgaris ESP-31 with microwave-assisted heating

    International Nuclear Information System (INIS)

    Bach, Quang-Vu; Chen, Wei-Hsin; Lin, Shih-Cheng; Sheen, Herng-Kuang; Chang, Jo-Shu

    2017-01-01

    Highlights: • A microwave-assisted heating system is used for wet torrefaction (WT) of microalga. • Microalga Chlorella vulgaris ESP-31 is adopted as the feedstock. • The ash content in the microalga is reduced after WT. • The calorific value of the microalga can be intensified up to 21% after WT. • At least 61.5% of energy in the biomass is retained after WT. - Abstract: Microalgae are a prime source of third generation biofuels. Many thermochemical processes can be applied to convert them into fuels and other valuable products. However, some types of microalgae are characterized by very high moisture and ash contents, thereby causing several problems in further conversion processes. This study presents wet torrefaction (WT) as a promising pretreatment method to overcome the aforementioned drawbacks coupled with microalgal biomass. For this purpose, a microwave-assisted heating system was used for WT of microalga Chlorella vulgaris ESP-31 at different reaction temperatures (160, 170, and 180 °C) and durations (5, 10, and 30 min). The results show several improvements in the fuel properties of the microalga after WT such as increased calorific value and hydrophobicity as well as reduced ash content. A correlation in terms of elemental analysis can be adopted to predict the higher heating value of the torrefied microalga. The structure analysis by Fourier transform infrared (FT-IR) spectroscopy reveals that the carbohydrate content in the torrefied microalgae is lowered, whereas their protein and lipid contents are increased if the WT extent is not severe. However, the protein and lipid contents are reduced significantly at more severe WT conditions. The thermogravimetric analysis shows that the torrefied microalgae have lower ignition temperatures but higher burnout temperatures than the raw microalga, revealing significant impact of WT on the combustion reactivity of the microalga. Overall, the calorific value of the microalga can be intensified up to

  5. 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

  6. Biosorption and toxicity responses to arsenite (As[III]) in Scenedesmus quadricauda.

    Science.gov (United States)

    Zhang, Jianying; Ding, Tengda; Zhang, Chunlong

    2013-08-01

    Toxicity and biosorption responses to arsenite (As[III]) were examined in a 96-h exposure study using Scenedesmus quadricauda, one of the most popular green algae distributed in freshwaters in China. Results indicated that the pH-dependent distribution of two arsenite species (H2AsO3(-) and H3AsO3) played an important role in biosorption and toxicity. The undissociated H3AsO3 was more toxic than its monoanionic H2AsO3(-) through comparison of algal cell numbers, chlorophyll-a contents, and algal ultrastructural changes observed with transmission electron microscopy. An effective biosorption of 89.0mgg(-1) at 100mgL(-1) As[III] was found in the treatments with an initial pH of 9.3 and 25.2μgg(-1) at 0.03mgL(-1) As[III] at an initial pH of 8.2 as a result of the predominant species of H2AsO3(-) under the ambient pH and Eh conditions. Our results imply that S. quadricauda may provide a new means for the removal of toxic arsenite species present in contaminated surface water. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. 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.

  8. 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.

  9. Calcium availability but not its content modulates metal toxicity in Scenedesmus quadricauda.

    Science.gov (United States)

    Kováčik, Jozef; Dresler, Sławomir

    2018-01-01

    Impact of calcium nutrition (pre-culture on solid medium with standard or elevated Ca dose, i. e. 0.17 and 4.40mM marked as low and high Ca) on acute metal toxicity (Cd, Mn and Pb, 24h of exposure to 10µM) in freshwater green alga Scenedesmus quadricauda was studied. Surprisingly, Ca content differed only slightly between low and high Ca samples and applied metals rather suppressed its amount. Na content was higher in metal-exposed high Ca samples, indicating that Ca/Na ratio may affect accumulation of metals. Content of heavy metals increased in order Cd < Mn < Pb and high Ca samples contained less metal than low Ca samples at least in absorbed fraction. Accumulation of ascorbic acid and thiols (GSH - glutathione and PC2 - phytochelatin 2) was affected mainly by Cd, GSH also by Mn and PC2 by Pb with often significant differences between low Ca and high Ca samples. Calcium nutrition also affected responses of algae to metals at the level of antioxidative enzyme activities (SOD, APX, and CAT) and elevated values were typically found in high Ca samples while ROS (hydrogen peroxide and superoxide radical) were mainly depleted in Mn treatment. These data confirm that Ca nutrition affects accumulation of metals in algae and metabolic parameters as observed in vascular plants but, unlike them, rather Ca/Na ratio than absolute Ca content seems to regulate the uptake of metals. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Stress-physiological reactions of the green alga Scenedesmus opoliensis to water pollution with herbicides

    Directory of Open Access Journals (Sweden)

    Zsolt Gyula KERESZTES

    2009-05-01

    Full Text Available The freshwater green alga Scenedesmus opoliensis proves to be a suitable bioindicator of water pollution with different herbicides. One of the best molecular markers of stress condition imposed by herbicides is overproduction of malondialdehyde resulting from lipid peroxidation in the damaged membranes. Methylviologen, a largely used pre-emergence herbicide which generates reactive oxygen species in the illuminated chloroplasts, triggers the accumulation of ascorbic acid and enhances the enzymatic activity of catalase, both of these substances being involved in the antioxidative protection of algal cells. Diuron, a herbicide that inhibits photosynthetic electron transport on the acceptor side of photosystem II, causes a decline in oxygen production and in biomass accumulation of algae. Glufosinate induces accumulation of toxic ammonia and leads to enhanced net oxygen production, associated with a low rate of carbon assimilation. Long-term exposure to micromolar concentrations of herbicides results in significant changes in the rate of cell division, in hotosynthetic parameters and in the intensity of antioxidative defense. A proper bioindication of toxic effects of herbicides on algae requires a selected combination of different physiological and biochemical parameters which reflect the degree of stress exerted on living organisms by water pollution with xenobiotic organic compounds.

  11. 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.

  12. 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.

  13. Management of autotrophic mass cultures of micro-algae

    CSIR Research Space (South Africa)

    Toerien, DF

    1987-01-01

    Full Text Available Interest in the mass cultivation of micro-algae as feed and foodstuff has existed since the turn of the century (Robinson and Toerien, 1962). Experiments using algae in photosynthetic research (Warburg, 1919) also led to an appreciation...

  14. High Lipid Induction in Microalgae for Biodiesel Production

    Directory of Open Access Journals (Sweden)

    Peer M. Schenk

    2012-05-01

    Full Text Available Oil-accumulating microalgae have the potential to enable large-scale biodiesel production without competing for arable land or biodiverse natural landscapes. High lipid productivity of dominant, fast-growing algae is a major prerequisite for commercial production of microalgal oil-derived biodiesel. However, under optimal growth conditions, large amounts of algal biomass are produced, but with relatively low lipid contents, while species with high lipid contents are typically slow growing. Major advances in this area can be made through the induction of lipid biosynthesis, e.g., by environmental stresses. Lipids, in the form of triacylglycerides typically provide a storage function in the cell that enables microalgae to endure adverse environmental conditions. Essentially algal biomass and triacylglycerides compete for photosynthetic assimilate and a reprogramming of physiological pathways is required to stimulate lipid biosynthesis. There has been a wide range of studies carried out to identify and develop efficient lipid induction techniques in microalgae such as nutrients stress (e.g., nitrogen and/or phosphorus starvation, osmotic stress, radiation, pH, temperature, heavy metals and other chemicals. In addition, several genetic strategies for increased triacylglycerides production and inducibility are currently being developed. In this review, we discuss the potential of lipid induction techniques in microalgae and also their application at commercial scale for the production of biodiesel.

  15. Improving microalgae for biotechnology - From genetics to synthetic biology

    Czech Academy of Sciences Publication Activity Database

    Hlavová, Monika; Turóczy, Zoltán; Bišová, Kateřina

    2015-01-01

    Roč. 33, č. 6 (2015), s. 1194-1203 ISSN 0734-9750 R&D Projects: GA MŠk EE2.3.30.0059; GA MŠk ED2.1.00/03.0110 Institutional support: RVO:61388971 Keywords : Microalgae * Genetics * Mutagenesis Subject RIV: EE - Microbiology, Virology Impact factor: 9.848, year: 2015

  16. Potential of sponges and microalgae for marine biotechnology

    NARCIS (Netherlands)

    Wijffels, R.H.

    2008-01-01

    Marine organisms can be used to produce several novel products that have applications in new medical technologies, in food and feed ingredients and as biofuels. In this paper two examples are described: the development of marine drugs from sponges and the use of microalgae to produce bulk chemicals

  17. Potential of industrial biotechnology with cyanobacteria and eukaryotic microalgae

    NARCIS (Netherlands)

    Wijffels, R.H.; Kruse, O.; Hellingwerf, K.J.

    2013-01-01

    Both cyanobacteria and eukaryotic microalgae are promising organisms for sustainable production of bulk products such as food, feed, materials, chemicals and fuels. In this review we will summarize the potential and current biotechnological developments.Cyanobacteria are promising host organisms for

  18. Photoacclimation state determines the photobehaviour of motile microalgae

    DEFF Research Database (Denmark)

    Ezequiel, João; Laviale, Martin; Frankenbach, Silja

    2015-01-01

    High productivity in intertidal microphytobenthic communities is achieved despite exposure to extreme and dynamic conditions (e.g. light, salinity, temperature). As an adaptation to this hostile environment, most of the microalgae species inhabiting fine-sediment habitats are motile, being able...

  19. MICROALGAE AS AN ALTERNATIVE TO BIOFUELS PRODUCTION. PART 1: BIOETHANOL

    Directory of Open Access Journals (Sweden)

    Maiara Priscilla de Souza

    2013-02-01

    Full Text Available The demand from the energy sector is one of the culminating factors to do researches that enable innovations in the biotechnology sector and to boost biofuel production. The variability of the existing feedstocks provides benefits to energy production, however, we must choose the ones that present plausible characteristics depending on the type of product that we want to obtained. In this context, it is noted that the microalgae have suitable characteristics to producing different types of fuels, depending on the type of treatment are subjected, the species being analyzed as well as the biochemical composition of the biomass. Bioethanol production from microalgae is a promising and growing energy alternative under a view that biomass of these microorganisms has an enormous biodiversity and contain high levels of carbohydrates, an indispensable factor for the bioconversion of microalgae in ethanol. Due to these factors, there is a constant search for more viable methods for pretreatment of biomass, hydrolysis and fermentation, having as one of the major aspects the approach of effectives methodologies in the ambit of quality and yield of ethanol. Therefore, we have to search to increase the interest in the developing of biofuels reconciling with the importance of using microalgae, analyzing whether these micro-organisms are capable of being used in bioethanol production.

  20. Technical Note: Development of a Photobioreactor for Microalgae ...

    African Journals Online (AJOL)

    In view of the technical and biological limitations of open pond systems, a study was conducted to develop a cost-effective experimental photobioreactor that would permit efficient cultivation of microalgae for biodiesel production. The photobioreactor was developed using low cost materi- als, cylindrical translucent tubes ...

  1. Rapid biodiesel production using wet microalgae via microwave irradiation

    International Nuclear Information System (INIS)

    Wahidin, Suzana; Idris, Ani; Shaleh, Sitti Raehanah Muhamad

    2014-01-01

    Highlights: • Lipid was directly extracted from wet microalgae using microwave irradiation. • The microwave irradiation and water bath-assisted solvent extraction are applied. • Cell walls are significantly disrupted under microwave irradiation. • Highly disrupted cell walls led to higher biodiesel yield in microwave irradiation. • Microwave irradiation is a promising direct technique with high biodiesel yields. - Abstract: The major challenges for industrial commercialized biodiesel production from microalgae are the high cost of downstream processing such as dewatering and drying, utilization of large volumes of solvent and laborious extraction processes. In order to address these issues the microwave irradiation method was used to produce biodiesel directly from wet microalgae biomass. This alternative method of biodiesel production from wet microalgae biomass is compared with the conventional water bath-assisted solvent extraction. The microwave irradiation extracted more lipids and high biodiesel conversion was obtained compared to the water bath-assisted extraction method due to the high cell disruption achieved and rapid transesterification. The total content of lipid extracted from microwave irradiation and water bath-assisted extraction were 38.31% and 23.01% respectively. The biodiesel produced using microwave irradiation was higher (86.41%) compared to the conventional method. Thus microwave irradiation is an attractive and promising technology to be used in the extraction and transesterification process for efficient biodiesel production

  2. Cultivation of microalgae on artificial light comes at a cost

    NARCIS (Netherlands)

    Blanken, W.M.; Cuaresma Franco, M.; Wijffels, R.H.; Janssen, M.G.J.

    2013-01-01

    Microalgae are potential producers of bulk food and feed compounds, chemicals, and biofuels. To produce these bulk products competitively, it is important to keep costs of raw material low. Light energy can be provided by sun or lamps. Sunlight is free and abundant. Disadvantages of sunlight,

  3. Cultivation of microalgae in a high irradiance area

    NARCIS (Netherlands)

    Cuaresma, M.

    2011-01-01


    Microalgae are a promising source of high-value products (i.e. carotenoids, ω-3 fatty acids), as well as feedstocks for food, bulk chemicals and biofuels. Industrial production is, however, still limited because the technology needs further development. One of the main bottlenecks is the

  4. Microalgae for the production of bulk chemicals and biofuels

    NARCIS (Netherlands)

    Wijffels, R.H.; Barbosa, M.J.; Eppink, M.H.M.

    2010-01-01

    The feasibility of microalgae production for biodiesel was discussed. Although algae are not yet produced at large scale for bulk applications, there are opportunities to develop this process in a sustainable way. It remains unlikely, however, that the process will be developed for biodiesel as the

  5. Extremophilic micro-algae and their potential contribution in biotechnology.

    Science.gov (United States)

    Varshney, Prachi; Mikulic, Paulina; Vonshak, Avigad; Beardall, John; Wangikar, Pramod P

    2015-05-01

    Micro-algae have potential as sustainable sources of energy and products and alternative mode of agriculture. However, their mass cultivation is challenging due to low survival under harsh outdoor conditions and competition from other, undesired, species. Extremophilic micro-algae have a role to play by virtue of their ability to grow under acidic or alkaline pH, high temperature, light, CO2 level and metal concentration. In this review, we provide several examples of potential biotechnological applications of extremophilic micro-algae and the ranges of tolerated extremes. We also discuss the adaptive mechanisms of tolerance to these extremes. Analysis of phylogenetic relationship of the reported extremophiles suggests certain groups of the Kingdom Protista to be more tolerant to extremophilic conditions than other taxa. While extremophilic microalgae are beginning to be explored, much needs to be done in terms of the physiology, molecular biology, metabolic engineering and outdoor cultivation trials before their true potential is realized. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Cultivation of micro-algae in closed tubular reactor

    Energy Technology Data Exchange (ETDEWEB)

    Gudin, C.; Bernard, A.; Chaumont, D.

    1983-11-01

    A description is presented of the three culture pilot utilities in activity under natural light, including glass tubular solar collector (30 mm diameter) in which the microalgae culture circulates. The utility is controled automatically (thermal regulation, gaseous transfers, continuous culture organization). The tests were conducted for the production of polysaccharides (Porphyridium cruentum, chlamydomonas mexicana) or hydrocarbons (Botriococcus braunii).

  7. Biodiesel production with microalgae as feedstock: from strains to biodiesel.

    Science.gov (United States)

    Gong, Yangmin; Jiang, Mulan

    2011-07-01

    Due to negative environmental influence and limited availability, petroleum-derived fuels need to be replaced by renewable biofuels. Biodiesel has attracted intensive attention as an important biofuel. Microalgae have numerous advantages for biodiesel production over many terrestrial plants. There are a series of consecutive processes for biodiesel production with microalgae as feedstock, including selection of adequate microalgal strains, mass culture, cell harvesting, oil extraction and transesterification. To reduce the overall production cost, technology development and process optimization are necessary. Genetic engineering also plays an important role in manipulating lipid biosynthesis in microalgae. Many approaches, such as sequestering carbon dioxide from industrial plants for the carbon source, using wastewater for the nutrient supply, and maximizing the values of by-products, have shown a potential for cost reduction. This review provides a brief overview of the process of biodiesel production with microalgae as feedstock. The methods associated with this process (e.g. lipid determination, mass culture, oil extraction) are also compared and discussed.

  8. Ingestion of Brachionus plicatilis under different microalgae conditions

    Science.gov (United States)

    Zhou, Wenli; Tang, Xuexi; Qiao, Xiuting; Wang, You; Wang, Renjun; Feng, Lei

    2009-09-01

    The effects of four microalgae, Chlorella vulgaris, Platymonas helgolandicavar, Isochrysis galbana, and Nitzschia closterium on the grazing and filtering rates of the marine rotifer, Brachionus plicatilis, were evaluated under laboratory conditions. The grazing rates in separate cultures of the four microalga were as follows: C. vulgaris > P. helgolandicavar > I. galbana > N. closterium. However, the filtering rates occurred in the following order: P. helgolandicavar > N. closterium > C. vulgaris > I. galbana. A mixed diets experiment revealed that P. helgolandicavar was the preferred diet of B. plicatilis. In addition, the grazing rate of B. plicatilis increased gradually as the density of the microalgae increased, until concentrations of 2.5×106 cells mL-1 for C. vulgaris and 1.5×106 cells mL-1 for I. galbana were obtained. Furthermore, the filtering rate increased slightly when the density of the microalgae was low, after which it declined as the microalgal density increased. The grazing rates of B. plicatilis were as follows during the different growth phases: stationary phase > exponential phase > lag phase > decline phase. Additionally, the filtering rates during the growth phases were: exponential phase > lag phase > stationary phase > decline phase. The results of this study provide foundational information that can be used to explore the optimal culture conditions for rotifers and to promote the development of aquaculture.

  9. Production of bio-jet fuel from microalgae

    Science.gov (United States)

    Elmoraghy, Marian

    The increase in petroleum-based aviation fuel consumption, the decrease in petroleum resources, the fluctuation of the crude oil price, the increase in greenhouse gas emission and the need for energy security are motivating the development of an alternate jet fuel. Bio-jet fuel has to be a drop in fuel, technically and economically feasible, environmentally friendly, greener than jet fuel, produced locally and low gallon per Btu. Bic jet fuel has been produced by blending petro-based jet fuel with microalgae biodiesel (Fatty Acid Methyl Ester, or simply FAME). Indoor microalgae growth, lipids extraction and transetrification to biodiesel are energy and fresh water intensive and time consuming. In addition, the quality of the biodiesel product and the physical properties of the bio-jet fuel blends are unknown. This work addressed these challenges. Minimizing the energy requirements and making microalgae growth process greener were accomplished by replacing fluorescent lights with light emitting diodes (LEDs). Reducing fresh water footprint in algae growth was accomplished by waste water use. Microalgae biodiesel production time was reduced using the one-step (in-situ transestrification) process. Yields up to 56.82 mg FAME/g dry algae were obtained. Predicted physical properties of in-situ FAME satisfied European and American standards confirming its quality. Lipid triggering by nitrogen deprivation was accomplished in order to increase the FAME production. Bio-jet fuel freezing points and heating values were measured for different jet fuel to biodiesel blend ratios.

  10. Combustion of Microalgae Oil and Ethanol Blended with Diesel Fuel

    Directory of Open Access Journals (Sweden)

    Saddam H. Al-lwayzy

    2015-12-01

    Full Text Available Using renewable oxygenated fuels such as ethanol is a proposed method to reduce diesel engine emission. Ethanol has lower density, viscosity, cetane number and calorific value than petroleum diesel (PD. Microalgae oil is renewable, environmentally friendly and has the potential to replace PD. In this paper, microalgae oil (10% and ethanol (10% have been mixed and added to (80% diesel fuel as a renewable source of oxygenated fuel. The mixture of microalgae oil, ethanol and petroleum diesel (MOE20% has been found to be homogenous and stable without using surfactant. The presence of microalgae oil improved the ethanol fuel demerits such as low density and viscosity. The transesterification process was not required for oil viscosity reduction due to the presence of ethanol. The MOE20% fuel has been tested in a variable compression ratio diesel engine at different speed. The engine test results with MOE20% showed a very comparable engine performance of in-cylinder pressure, brake power, torque and brake specific fuel consumption (BSFC to that of PD. The NOx emission and HC have been improved while CO and CO2 were found to be lower than those from PD at low engine speed.

  11. Biomass of Microalgae as a Source of Renewable Energy

    Directory of Open Access Journals (Sweden)

    Głowacka Natalia

    2017-05-01

    Full Text Available Algae represent a potential source of energy via anaerobic digestion. The aim of the study was to obtain the possible potential of green microalgae, which could replace the commonly used corn silage for the production of biogas in the future. The intensive construction of new biogas plants stations across Europe and the lack of arable land suitable for the cultivation of biomass for energy purposes are the fundamental reasons behind looking for the alternative raw materials for energy production as a substitute for commonly used input materials. When comparing green microalgae with conventional crops the high productivity potential (high oil content as well as the possibility of their production during the whole year can be noticed. It is necessary to find the effective way to produce biomass from green microalgae, proper for energy conversion, while ensuring the economic and environmental aspects. The interim research results mentioned in this article indicate that microalgae present appropriate alternative material for the process of anaerobic digestion.

  12. Biodiesel Production from Microalgae by Extraction – Transesterification Method

    Directory of Open Access Journals (Sweden)

    Nguyen Thi Phuong Thao

    2013-11-01

    Full Text Available The environmental impact of using petroleum fuels has led to a quest to find a suitable alternative fuel source. In this study, microalgae were explored as a highly potential feedstock to produce biodiesel fuel. Firstly, algal oil is extracted from algal biomass by using organic solvents (n–hexan.  Lipid is contained in microalgae up to 60% of their weight. Then, Biodiesel is created through a chemical reaction known as transesterification between algal oil and alcohol (methanol with strong acid (such as H2SO4 as the catalyst. The extraction – transesterification method resulted in a high biodiesel yield (10 % of algal biomass and high FAMEs content (5.2 % of algal biomass. Biodiesel production from microalgae was studied through experimental investigation of transesterification conditions such as reaction time, methanol to oil ration and catalyst dosage which are deemed to have main impact on reaction conversion efficiency. All the parameters which were characterized for purified biodiesel such as free glycerin, total glycerin, flash point, sulfur content were analyzed according to ASTM standardDoi: http://dx.doi.org/10.12777/wastech.1.1.6-9Citation:  Thao, N.T.P., Tin, N.T., and Thanh, B.X. 2013. Biodiesel Production from Microalgae by Extraction – Transesterification Method. Waste Technology 1(1:6-9. Doi: http://dx.doi.org/10.12777/wastech.1.1.6-9

  13. Prospective of biodiesel production utilizing microalgae as the cell ...

    African Journals Online (AJOL)

    Microalgae are sunlight-driven miniature factories that convert atmospheric CO2 to polar and neutral lipids which after esterification can be utilized as an alternative source of petroleum. Further, other metabolic products such as bioethanol and biohydrogen produced by algal cells are also being considered for the same ...

  14. Physicochemical approach to freshwater microalgae harvesting with magnetic particles

    Czech Academy of Sciences Publication Activity Database

    Procházková, G.; Podolová, N.; Šafařík, Ivo; Zachleder, Vilém; Brányik, T.

    2013-01-01

    Roč. 112, DEC 2013 (2013), s. 213-218 ISSN 0927-7765 R&D Projects: GA ČR(CZ) GAP503/10/1270 Institutional support: RVO:67179843 ; RVO:61388971 Keywords : microalgae * cell adhesion * magnetic beads * surface interactions * XDLVO theory Subject RIV: EH - Ecology, Behaviour; EI - Biotechnology ; Bionics (MBU-M) Impact factor: 4.287, year: 2013

  15. Lichen microalgae are sensitive to environmental concentrations of atrazine.

    Science.gov (United States)

    Traba, Helena Moreno; Domínguez-Morueco, Noelia; Barreno, Eva; Catalá, Myriam

    2017-04-03

    The identification of new organisms for environmental toxicology bioassays is currently a priority, since these tools are strongly limited by the ecological relevance of taxa used to study global change. Lichens are sensitive bioindicators of air quality and their microalgae are an untapped source for new low-cost miniaturized bioassays with ecological importance. In order to increase the availability of a wider range of taxa for bioassays, the sensitivity of two symbiotic lichen microalgae, Asterochloris erici and Trebouxia sp. TR9, to atrazine was evaluated. To achieve this goal, axenic cultures of these phycobionts in suspension were exposed to a range of environmental concentrations of the herbicide atrazine, a common water pollutant. Optical density and chlorophyll autofluorescence were used as endpoints of ecotoxicity and ecophysiology on cell suspensions. Results show that lichen microalgae show high sensitivity to very low doses of atrazine, being higher in Asterochloris erici than in Trebouxia sp. TR9. We conclude that environmental concentrations of atrazine could modify population dynamics probably through a shift in reproduction strategies of these organisms. This seminal work is a breakthrough in the use of lichen microalgae in the assessment of micropollution effects on biodiversity.

  16. Edible oils from microalgae: insights in TAG accumulation

    NARCIS (Netherlands)

    Klok, A.J.; Lamers, P.P.; Martens, D.E.; Draaisma, R.B.; Wijffels, R.H.

    2014-01-01

    Microalgae are a promising future source for sustainable edible oils. To make microalgal oil a cost-effective alternative for common vegetable oils, increasing TAG productivity and TAG content are of high importance. Fulfilling these targets requires proper understanding of lipid metabolism in

  17. Hazard and risk of herbicides for marine microalgae

    NARCIS (Netherlands)

    Sjollema, S.B.; Martínez-García, G.; van der Geest, H.G.; Kraak, M.H.S.; Booij, P.; Vethaak, A.D.; Admiraal, W.

    2014-01-01

    Due to their specific effect on photosynthesis, herbicides pose a potential threat to coastal and estuarine microalgae. However, comprehensive understanding of the hazard and risk of these contaminants is currently lacking. Therefore the aim of the present study was to investigate the toxic effects

  18. Hazard and risk of herbicides for marine microalgae

    International Nuclear Information System (INIS)

    Sjollema, Sascha B.; MartínezGarcía, Gema; Geest, Harm G. van der; Kraak, Michiel H.S.; Booij, Petra; Vethaak, A. Dick; Admiraal, Wim

    2014-01-01

    Due to their specific effect on photosynthesis, herbicides pose a potential threat to coastal and estuarine microalgae. However, comprehensive understanding of the hazard and risk of these contaminants is currently lacking. Therefore the aim of the present study was to investigate the toxic effects of four ubiquitous herbicides (atrazine, diuron, Irgarol ® 1051 and isoproturon) and herbicide mixtures on marine microalgae. Using a Pulse Amplitude Modulation (PAM) fluorometry based bioassay we demonstrated a clear species and herbicide specific toxicity and showed that the current environmental legislation does not protect algae sufficiently against diuron and isoproturon. Although a low actual risk of herbicides in the field was demonstrated, monitoring data revealed that concentrations occasionally reach potential effect levels. Hence it cannot be excluded that herbicides contribute to observed changes in phytoplankton species composition in coastal waters, but this is likely to occur only occasionally. - Highlights: • The hazard of herbicides for microalgae is compound and species specific. • In general a low risk although occasional potential effect levels are reached. • Current legislation does not protect marine microalgae sufficiently. - The hazard of herbicides in the coastal waters is compound and species specific and although the general risk in the field is low, occasionally potential effect levels are reached

  19. Analysis and stability of fatty acid esterified xanthophylls from microalgae

    NARCIS (Netherlands)

    Weesepoel, Y.J.A.

    2014-01-01

    Fatty acid esterified xanthophylls (e.g. astaxanthin) produced by microalgae are regarded as a natural alternative for food colourants, but little is known on the stability of these compounds in foods. The aims of this research were (i) to develop protocols to analyze esterified

  20. Vibrating membrane filtration as improved technology for microalgae dewatering.

    Science.gov (United States)

    Nurra, Claudia; Clavero, Ester; Salvadó, Joan; Torras, Carles

    2014-04-01

    The effect of shear-enhanced filtration by vibratory process in microalgae dewatering is presented in this paper. The aim of this research was to investigate the technical performance and improvement of vibrating membrane filtration compared with conventional tangential cross-flow filtration in microalgae concentration. An industrial-scale available commercial set-up was used. Several membrane materials as polyethersulfone, polyacrylonitrile, etc., and mean pore sizes (from 7000Da to 0.2μm) were tested and compared in both filtration set-ups. Experiments were carried-out with Nannochloropsis gaditana and Phaeodactylum tricornutum microalgae. It has been demonstrated that, even if the choice of the membrane depends on its cut-off, its material and the type of microalgae filtrated, dynamic filtration is always the best technology over a conventional one. If with conventional filtration permeability values were in the vicinity of 10L/h/m(2)/bar in steady state phase, with dynamic filtration these values increased to 30L/h/m(2)/bar or more. Copyright © 2014 Elsevier Ltd. All rights reserved.