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

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

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Mario Andres Forero-Cujiño

2016-05-01

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

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.

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.)

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

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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.

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

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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.

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

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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.

Aeration strategy for biofilm cultivation of the microalga Scenedesmus dimorphus.

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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).

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

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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.

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

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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

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)

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

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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.

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

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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 �

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

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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.

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

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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.

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

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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.

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.

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

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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...

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.

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

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

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.

Comparison of nutrient removal capacity and biomass settleability of four high-potential microalgal species.

Science.gov (United States)

Su, Yanyan; Mennerich, Artur; Urban, Brigitte

2012-11-01

Four common used microalgae species were compared in terms of settleability, nutrient removal capacity and biomass productivity. After 1 month training, except cyanobacteria Phormidium sp., three green microalgae species, Chlamydomonas reinhardtii, Chlorella vulgaris and Scenedesmus rubescens, showed good settleability. The N and P removal efficiency was all above 99% within 7, 4, 6 and 6 days for N and 4, 2, 3 and 4 days for P, resulting in the N removal rates of 3.66±0.17, 6.39±0.20, 4.39±0.06 and 4.31±0.18 mg N/l/d and P removal rates of 0.56±0.07, 0.89±0.05, 0.76±0.09 and 0.60±0.05 mg P/l/d for Phormidium sp., C. reinhardtii, C. vulgaris and S. rubescens, respectively. Phormidium sp. had the lowest algal biomass productivity (2.71±0.7 g/m(2)/d) and the other three green microalgae showed higher algal biomass productivity (around 6 g/m(2)/d). Assimilation into biomass was the main removal mechanism for N and P. Copyright © 2012 Elsevier Ltd. All rights reserved.

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.

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.

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

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.

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..

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

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.

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.

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

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

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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.

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 ...

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

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.

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

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.

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.

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

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.

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

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.

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.

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 ...

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.

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.

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.

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

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.

Study on the Application of Chinese Patent Drug and Chinese Formula of Rabdosia Rubescens

Science.gov (United States)

Peng, Mengfan; Liu, Baosong; Mao, Mingsan

2018-01-01

Rabdosia rubescens contais many active ingredients such as terpenoids, flavonoids, polysaccharides and organic acids. Modern research has proved that Rabdosia rubescens has the effect of heat-clearing and detoxicating, antibacterial and anticancer, promoting blood circulation to arrest pain and anti-tumor. It is used in the treatment of sore throat, rheumatoid arthritis and various kinds of cancer. The clinical application of Rabdosia rubescens is restricted in the fat-soluble components, and the solubility of water solubility is ignored. The application of prescriptions, Chinese patent drug and food therapy of Rabdosia rubescens are less and fragmented. This paper inquires relevant literature, the application of Rabdosia rubescens in prescription, Chinese patent medicine and food therapy was reviewed, in order to make Rabdosiae rubescens play a greater role in the relevant area. On the basis of make the best use of everything, to promote the innovation and development of Chinese medicine and services to the people in our country.

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.

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.

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.)

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

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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

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.

Fatty Acid Content of Indonesian Aquatic Microalgae

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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.

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

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.

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

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A. A. Ortega-Salas

2012-01-01

Full Text Available Se cultivaron las microalgas dulceacuícolas Kirchneriella obesa (G. S. West Schmidle 1893, Scenedesmus quadricauda (Chodat, Turpin Bréb 1835 y Chlorococcum infusorium (Schrank Meneghini 1842, con el propósito comparar las tasas de crecimiento y su rendimiento en tres medios de cultivo, el F/2 de Guillard, Fert I y Fert II. El agua utilizada se pasó en filtros de cinco, uno y 0.45 mm, y se trató con luz ultravioleta. La temperatura varió de 24 a 25°C. Se cultivaron en un sistema de volumen creciente a partir de recipientes de 62.5 mL, duplicando el medio de cultivo cada 24 h, con el fin de completar 32 L en nueve días. Cada 24 h se obtuvieron tres muestras de 1 a 10 mL del cultivo, se preservaron en una solución de lugol y se calculó la concentración de las microalgas cada 24 h. El número total de células de las tres especies aumentó de manera exponencial hasta el final de los experimentos en los medios de cultivo F/2 y Fert I; esto no fue así con el medio Fert II, en el cual la tasa de duplicación y el número total de divisiones fueron más bajas. El medio F/2 y el Fert I ofrecieron mejores resultados que el Fert II. Los medios Fert I y Fert II tienen un valor económico más bajo que el medio F/2. El crecimiento y el rendimiento fueron mejores con el medio F/2, seguido por FI y FII.

Evaluation of the Antioxidant Activity of Cell Extracts from Microalgae

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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.

Insights into Microalga and Bacteria Interactions of Selected Phycosphere Biofilms Using Metagenomic, Transcriptomic, and Proteomic Approaches

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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.

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.

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.

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.

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.

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.

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.

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.

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

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.

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

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.

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.

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. ...

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.

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

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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.

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.

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.

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.

In-situ optical and acoustical measurements of the buoyant cyanobacterium p. Rubescens: spatial and temporal distribution patterns.

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Hilmar Hofmann

Full Text Available Optical (fluorescence and acoustic in-situ techniques were tested in their ability to measure the spatial and temporal distribution of plankton in freshwater ecosystems with special emphasis on the harmful and buoyant cyanobacterium P. rubescens. Fluorescence was measured with the multi-spectral FluoroProbe (Moldaenke FluoroProbe, MFP and a Seapoint Chlorophyll Fluorometer (SCF. In-situ measurements of the acoustic backscatter strength (ABS were conducted with three different acoustic devices covering multiple acoustic frequencies (614 kHz ADCP, 2 MHz ADP, and 6 MHz ADV. The MFP provides a fast and reliable technique to measure fluorescence at different wavelengths in situ, which allows discriminating between P. rubescens and other phytoplankton species. All three acoustic devices are sensitive to P. rubescens even if other scatterers, e.g., zooplankton or suspended sediment, are present in the water column, because P. rubescens containing gas vesicles has a strong density difference and hence acoustic contrast to the ambient water and other scatterers. After calibration, the combination of optical and acoustical measurements not only allows qualitative and quantitative observation of P. rubescens, but also distinction between P. rubescens, other phytoplankton, and zooplankton. As the measuring devices can sample in situ at high rates they enable assessment of plankton distributions at high temporal (minutes and spatial (decimeters resolution or covering large temporal (seasonal and spatial (basin scale scales.

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.

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.

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.

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).

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

Biodegradation of benzo(a)pyrene by two freshwater microalgae Selenastrum capricornutum and Scenedesmus acutus: a comparative study useful for bioremediation.

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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.

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

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

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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.

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

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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 .

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

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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.

Sprectroradiometric characteristics of inland water bodies infestated by Oscillatoria rubescens algae

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Ciraolo, Giuseppe; La Loggia, Goffredo; Maltese, Antonino

2010-10-01

In December 2006 blooms of Oscillatoria rubescens were found in the reservoir Prizzi in Sicily. Oscillatoria is a genus of filamentous alga comprising approximately 6 species, between these the O. rubescens is sadly famous since this organism produces microcystins which are powerful hepatotoxins. Firstly found in Europe in 1825 on Geneva lake, recently (2006) those algae has been find out in Pozzillo, Nicoletti e Ancipa reservoirs (Enna Province), as well as in Prizzi (Palermo Province) and Garcia reservoirs (Trapani Province). Toxins produced by those bacteria (usually called microcystine LR-1 and LR-2) are highly toxic since they can activate oncogenes cells causing cancer pathologies on liver and gastrointestinal tract. Even if water treatment plants should ensure the provision of safe drinking water from surface waters contaminated with those toxic algae blooms, the contamination of reservoirs used for civil and agricultural supply highlights human health risks. International literature suggests a threshold value of 0.01 μgl-1 to avoid liver cancer using water coming from contaminated water bodies for a long period. Since O. rubescens activities is strongly related to phosphate and nitrogen compounds as well as to temperature and light transmission within water, the paper presents the comparison between optical properties of the water of an infested reservoir and those of a reservoir characterized by clear water. Field campaigns were carried out in February-March 2008 in order to quantify the spectral transparencies of two water bodies through the calculation of the diffuse attenuation coefficient, measuring underwater downwelling irradiance at different depths as well as water spectral reflectance. Results show that diffuse attenuation coefficient is reduced by approximately 15% reducing light penetration in the water column; coherently reflectance spectral signature generally decreases, exhibiting a characteristic peak around 703 nm not present in

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

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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.

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

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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

Antibacterial Activities and Mechanism of Action of Acetone Extracts from Rabdosia rubescens

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Li Ping Cheng

2014-12-01

Full Text Available The antibacterial activities and mechanism of action of acetone extracts from R. rubescens were reported in this paper. The results showed that 80% acetone extracts had both the highest contents of total phenolics and flavonoids. Acetone extracts showed better antibacterial activities against Gram-positive bacterial strains and there were no inhibitory effects found on tested Gram-negative bacteria. In addition, 80% acetone extracts from R. rubescens had relatively higher antibacterial activities with the lowest values of MIC and MBC at 2.5 mg/mL and 5 mg/mL against B. subtilis. The antibacterial mechanism of 80% acetone extracts against Bacillus subtilis might be described as disrupting cell wall, increasing cell membrane permeability, and finally leading to the leakage of cell constituents

Characterization of the flocculating agent from the spontaneously flocculating microalga Chlorella vulgaris JSC-7.

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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.

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

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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.

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

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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.

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.

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

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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

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

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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.

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

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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.

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)

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

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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.

Analysis of the transcriptome of Isodon rubescens and key enzymes involved in terpenoid biosynthesis

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Xiuhong Su

2016-05-01

Full Text Available Isodon rubescens is an important medicinal plant in China that has been shown to reduce tumour growth due to the presence of the compound oridonin. In an effort to facilitate molecular research on oridonin biosynthesis, we reported the use of next generation massively parallel sequencing technologies and de novo transcriptome assembly to gain a comprehensive overview of I. rubescens transcriptome. In our study, a total of 50,934,276 clean reads, 101,640 transcripts and 44,626 unigenes were generated through de novo transcriptome assembly. A number of unigenes – 23,987, 10,263, 7359, 18,245, 17,683, 19,485, 9361 – were annotated in the National Center for Biotechnology Information (NCBI non-redundant protein (Nr, NCBI nucleotide sequences (Nt, Kyoto Encyclopedia of Genes and Genomes (KEGG Orthology (KO, Swiss-Prot, protein family (Pfam, gene ontology (GO, eukaryotic ortholog groups (KOG databases, respectively. Furthermore, the annotated unigenes were functionally classified according to the GO, KOG and KEGG. Based on these results, candidate genes encoding enzymes involved in terpenoids backbone biosynthesis were detected. Our data provided the most comprehensive sequence resource available for the study on I. rubescens, as well as demonstrated the effective use of Illumina sequencing and de novo transcriptome assembly on a species lacking genomic information.

Low antiplasmodial activity of alkaloids and amides from the stem bark of Zanthoxylum rubescens (Rutaceae

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Penali L.

2007-06-01

Full Text Available The stem bark of Zanthoxylum rubescens (syn. Fagara rubescens is used for treating fevers associated with malaria in the Ivory Coast. Three alkaloids: N-nornitidine, 7,9-dimethoxy-2,3- methylenedioxybenzophenanthridine, and bis[6-(5,6- dihydrochelerythrinyl] ether; and two amides: zanthomamide and lemairamide, were isolated from the stem bark of this plant. These compounds were screened in vitro against the chloroquine-sensitive 3D7 strain and the chloroquine-resistant FCM29 strain of P. falciparum. N-nornitidine was found to be inactive. 7,9- dimethoxy-2,3-methylenedioxybenzophenanthridine, lemairamide and zanthomamide showed weak activity with average IC50 values ranging from 45.6 μM to 149.9 μM. Bis[6-(5,6- dihydrochelerythrinyl] ether was the most active of the tested compounds with mean IC50s of 14.9 ± 1.4 μM in FCM29 strain and 15.3 ± 3.4 μM in 3D7 strain (~ 58 to ~ 1130 times less active than chloroquine respectively. The anti-Plasmodium activities of the tested alkaloids of Z. rubescens were low; and do not encourage the use of this plant as antimalarial.

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

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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.

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

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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.

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

A one-stage cultivation process for lipid- and carbohydrate-rich biomass of Scenedesmus obtusiusculus based on artificial and natural water sources.

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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.

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

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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.

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

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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.

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

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

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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.

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

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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.

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.

Biosynthesis of the oxygenated diterpene nezukol in the medicinal plant Isodon rubescens is catalyzed by a pair of diterpene synthases.

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Kyle A Pelot

Full Text Available Plants produce an immense diversity of natural products (i.e. secondary or specialized metabolites that offer a rich source of known and potentially new pharmaceuticals and other desirable bioproducts. The Traditional Chinese Medicinal plant Isodon rubescens (Lamiaceae contains an array of bioactive labdane-related diterpenoid natural products. Of these, the ent-kauranoid oridonin is the most prominent specialized metabolite that has been extensively studied for its potent antimicrobial and anticancer efficacy. Mining of a previously established transcriptome of I. rubescens leaf tissue identified seven diterpene synthase (diTPSs candidates. Here we report the functional characterization of four I. rubescens diTPSs. IrTPS5 and IrTPS3 were identified as an ent-copalyl diphosphate (CPP synthase and a (+-CPP synthase, respectively. Distinct transcript abundance of IrTPS5 and the predicted ent-CPP synthase IrTPS1 suggested a role of IrTPS5 in specialized ent-kaurene metabolism possibly en route to oridonin. Nicotiana benthamiana co-expression assays demonstrated that IrTPS4 functions sequentially with IrTPS3 to form miltiradiene. In addition, IrTPS2 converted the IrTPS3 product (+-CPP into the hydroxylated tricyclic diterpene nezukol not previously identified in I. rubescens. Metabolite profiling verified the presence of nezukol in I. rubescens leaf tissue. The proposed IrTPS2-catalyzed reaction mechanism proceeds via the common ionization of the diphosphate group of (+-CPP, followed by formation of an intermediary pimar-15-en-8-yl+ carbocation and neutralization of the carbocation by water capture at C-8 to yield nezukol, as confirmed by nuclear magnetic resonance (NMR analysis. Oxygenation activity is rare for the family of class I diTPSs and offers new catalysts for developing metabolic engineering platforms to produce a broader spectrum of bioactive diterpenoid natural products.

Simultaneous characterization and quantification of 17 main compounds in Rabdosia rubescens by high performance liquid chromatography

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Sen Guo

2017-04-01

Full Text Available Rabdosia rubescens is a healthy herbal tea and well-known Chinese medicinal herb. To evaluate the quality of R. rubescens from China, a high performance liquid chromatography method with dual-wavelength detection was developed and validated. The method was successfully applied for the simultaneous characterization and quantification of 17 main constituents from four different cultivation regions in China. Under optimal conditions, analysis was performed on a Luna C-18 column and gradient elution with a solvent system of acetonitrile and 0.5% (v/v acetic acid–water at a flow rate of 1.0 mL/min and wavelength of 220 nm and 280 nm. All standard calibration curves exhibited good linearity (r2 > 0.9992 within the test ranges. The precision was evaluated by intraday and interday tests, which revealed relative standard deviation values within the ranges of 0.57–2.35% and 0.52–3.40%, respectively. The recoveries were in the range of 96.37–101.66%. The relative standard deviation values for stability and repeatability were < 5%. The contents of some compounds were low and varied with different cultivars. The proposed method could serve as a prerequisite for quality control of R. rubescens materials and products.

Effects of the Rabdosia rubescens total flavonoids on focal cerebral ischemia reperfusion model in rats

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Mingsan Miao

2017-05-01

Full Text Available The effect of the Rabdosia rubescens total flavonoids on focal cerebral ischemia reperfusion model in rats was observed. The model group, nimodipine group, cerebral collateral group, and large, medium and small dose group of the Rabdosia rubescens total flavonoids were administered with corresponding drugs but sham operation group and model group were administered the same volume of 0.5%CMC, 1 times a day, continuous administration of 7 d. After 1 h at 7 d to medicine, left incision in the middle of the neck of rats after anesthesia, we can firstly expose and isolate the left common carotid artery (CCA, and then expose external carotid artery (ECA and internal carotid artery (ICA. The common carotid artery and the external carotid artery are ligated. Then internal carotid artery with arterial clamp is temporarily clipped. Besides, cut the incision of 0.2 mm from 5 cm of the bifurcation of the common carotid artery. A thread Line bolt is inserted with more than 18–20 mm from bifurcation of CCA into the internal carotid artery until there is resistance. Then the entrance of the middle cerebral artery is blocked and internal carotid artery is ligated (the blank group only exposed the left blood vessel without Plugging wire. Finally it is gently pulled out the plug line after 2 h. Results: Compared with the model mice, Rabdosia rubescens total flavonoids can significantly relieve the injury of brain in hippocampus and cortex nerve cells; experimental rat focal cerebral ischemia was to improve again perfusion model of nerve function defect score mortality; significantly reduce brain homogenate NOS activity and no content, MDA, IL-1, TNF-a, ICAM-1 content; increase in brain homogenate SOD and ATPase activity (P < 0.05, P < 0.01; and reduce the serum S-100β protein content. Each dose group of the Rabdosia rubescens total flavonoids has a better Improvement effect on focal cerebral ischemia reperfusion model in rats.

Evaluation of the potential for some isolated microalgae to produce biodiesel

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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.

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

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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.

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

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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.

Health risk evaluation associated to Planktothrix rubescens: An integrated approach to design tailored monitoring programs for human exposure to cyanotoxins.

Science.gov (United States)

Manganelli, Maura; Scardala, Simona; Stefanelli, Mara; Vichi, Susanna; Mattei, Daniela; Bogialli, Sara; Ceccarelli, Piegiorgio; Corradetti, Ernesto; Petrucci, Ines; Gemma, Simonetta; Testai, Emanuela; Funari, Enzo

2010-03-01

Increasing concern for human health related to cyanotoxin exposure imposes the identification of pattern and level of exposure; however, current monitoring programs, based on cyanobacteria cell counts, could be inadequate. An integrated approach has been applied to a small lake in Italy, affected by Planktothrix rubescens blooms, to provide a scientific basis for appropriate monitoring program design. The cyanobacterium dynamic, the lake physicochemical and trophic status, expressed as nutrients concentration and recycling rates due to bacterial activity, the identification/quantification of toxic genotype and cyanotoxin concentration have been studied. Our results indicate that low levels of nutrients are not a marker for low risk of P. rubescens proliferation and confirm that cyanobacterial density solely is not a reliable parameter to assess human exposure. The ratio between toxic/non-toxic cells, and toxin concentrations, which can be better explained by toxic population dynamic, are much more diagnostic, although varying with time and environmental conditions. The toxic fraction within P. rubescens population is generally high (30-100%) and increases with water depth. The ratio toxic/non-toxic cells is lowest during the bloom, suggesting a competitive advantage for non-toxic cells. Therefore, when P. rubescens is the dominant species, it is important to analyze samples below the thermocline, and quantitatively estimate toxic genotype abundance. In addition, the identification of cyanotoxin content and congeners profile, with different toxic potential, are crucial for risk assessment. Copyright 2009 Elsevier Ltd. All rights reserved.

Isolation and Purification of Oridonin from the Whole Plant of Isodon rubescens by High-Speed Counter-Current Chromatography

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ChunYue Yu

2011-09-01

Full Text Available Semi-preparative high-speed counter-current chromatography (HSCCC was successfully used for isolation and purification of oridonin from Isodon rubescens by using a two-phase-solvent system composed of n-hexane-ethyl acetate-methanol-water (2.8:5:2.8:5, v/v/v/v. The targeted compound isolated, collected and purified by HSCCC was analyzed by high performance liquid chromatography (HPLC. A total of 40.6 mg of oridonin with the purity of 73.5% was obtained in less than 100 min from 100 mg of crude Isodon rubescens extract. The chemical structure of the compound was identified by IR, 1H-NMR and 13C-NMR.

Evaluation of novel thermo-resistant Micractinium and Scenedesmus sp. for efficient biomass and lipid production under different temperature and nutrient regimes.

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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.

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...

New records of Scenedesmus Meyen from China

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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.

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.

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.

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.

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

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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.

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.

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.)

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.

Antinociceptive effect of critoniella acuminata, physalis peruviana and salvia rubescens

OpenAIRE

Munóz, Carol; Vergel, Nadezdha E.; Aragón, Diana Marcela; Ospina, Luis Fernando

2010-01-01

Se evaluó el efecto antinociceptivo de extractos, fracciones y compuestos de Critoniella acuminata, Physalis peruviana y Salvia rubescens mediante los métodos de placa caliente, contorsiones abdominales inducidas por ácido acético y ensayo de la formalina. La fracción de Critoniella acuminata en dosis de 100 mg/kg p.o. presentó actividad antinociceptiva al aumentar el tiempo de reacción del animal ante la aplicación de un estímulo térmico (método de la placa caliente), mient...

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

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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.

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

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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.

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

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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.

A New Asymmetric ent-Kauranoid Dimer from Rabdosia rubescens

Institute of Scientific and Technical Information of China (English)

LU Hai-ying; LIANG Jing-yu

2012-01-01

Objective To study the ent-kaurane diterpenoids from Rabdosia rubescens.Methods The compounds were isolated by chromatographies and their structures were identified by spectral analyses.Results Four compounds were isolated,and they were identified as bisrubescensin E (1),2α,3α,24-trihydroxyurs-12-en-28-oic acid (2),2α,3α,24-trihydroxyurs-12,20-(30)-dien-28-oic acid (3),and 6,7-dihydroxycoumarin (4).Conclusion Compound 1 is a new asymmetric ent-kauranoid dimer.Compound 2 is isolated from the plant for the first time.Compounds 3 and 4 are isolated from the plants ofRabdosia (B1.) Hassk for the first time.

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.

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.

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.

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.

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.

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

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.

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)

Phycoremediation of Heavy Metals in Wet Market Wastewater

Science.gov (United States)

Apandi, Najeeha; Saphira Radin Mohamed, Radin Maya; Al-Gheethi, Adel; Latiffi, Atikah; Nor Hidayah Arifin, Siti; Gani, Paran

2018-04-01

The efficiency of phycoremediation using microalgae for removing nutrients and heavy metals from wastewaters has been proved. However, the differences in the composition of wastewaters as well as microalgae species play an important role in the efficient of this process. Therefore, the present study aimed to investigate the effectiveness of Scenedesmus sp. to removal of heavy metals from wet market wastewater. Scenedesmus sp. was inoculated with 106 cells/mL into each wet market wastewater concentration included 10, 25, 50, 75 and 100% and incubated for 18 days. The highest growth rate was recorded in 50% WM with a maximum dry weight of 2006 mg L-1 which subsequently removed 93.06% of Cd, 91.5% of Cr, 92.47% of Fe, 92.40% of Zn. These findings reflected the high potential of Scenedesmus sp. in the treatment of wet market wastewater and production microalgae biomass.

Aqueous extract of Rabdosia rubescens leaves: forming nanoparticles, targeting P-selectin, and inhibiting thrombosis

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Wang Y

2015-11-01

Full Text Available Yuji Wang,1 Jingcheng Tang,1 Haimei Zhu,1 Xueyun Jiang,1 Jiawang Liu,1 Wenyun Xu,1 Haiping Ma,1 Qiqi Feng,1 Jianhui Wu,1 Ming Zhao,1,2 Shiqi Peng1 1Beijing Area Major Laboratory of Peptide and Small Molecular Drugs, Engineering Research Center of Endogenous Prophylactic of Ministry of Education of China, Beijing Laboratory of Biomedical Materials, College of Pharmaceutical Sciences, Capital Medical University, Beijing, People’s Republic of China; 2Faculty of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan Abstract: The hot water extract of Rabdosia rubescens was traditionally used as an antithrombotic medicine. To explore its antithrombotic utility and mechanism, we carried out a series of in vitro and in vivo assays in this study. In vitro platelet aggregation assay showed that the half maximal inhibitory concentration values of aqueous extract of R. rubescens leaves (AERL inhibiting platelet aggregation induced by thrombin, arachidonic acid, adenosine diphosphate, and platelet-activating factor ranged from 0.12 mg/mL to 1.43 mg/mL. The minimal effective oral dose of AERL inhibiting the rats from forming thrombus was 25 mg/kg. Both in vitro and in vivo actions were correlated with AERL concentration-dependently inhibiting sP-selectin release. In water, AERL formed nanoparticles, and their size depended on the concentration. Docking the five nucleotides, 21 phenolic acids, and four diterpenoids identified by high-performance liquid chromatography–photodiode array detector/(-electrospray ionization-tandem mass spectrometry analysis into the active site of P-selectin, rosmarinic acid was predicted to be the antithrombotic ingredient of AERL. In flow cytometry analysis, 1 µM of rosmarinic acid effectively inhibited sP-selectin release in arachidonic acid-activated platelets. In a rat model, 5 mg/kg of oral rosmarinic acid effectively inhibited thrombosis. Keywords: R. rubescens, s

Effect of total flavonoid in rabdosia rubescens on tolerant mice models under cerebral anoxia

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Le Kang

2017-12-01

Conclusion: The total flavonoid in rabdosia rubescens can stimulate an endogenous protective mechanism by inducing the release of low levels of cytokines NO and NOS, which reduces the release of serum NSE, relieves the brain tissue ischemia-reperfusion injury, and further improves the protection effect of ischemic preconditioning on brain injury. The damage of brain tissue ischemia and reperfusion, and further improve the ischemia Protective effect of preconditioning on brain injury.

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.

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.

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

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.

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

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.

Study of mechanical properties of Palosangre wood (Brosimum rubescens Taub.), from Leticia-Colombia provenance

International Nuclear Information System (INIS)

Triana Gomez, Max Alejandro; Gonzalez Roso, Gladis; Paspur Posso, Segundo Demetrio

2008-01-01

The technical recommendations of the Pan-American Committee of Technical Norms COPANT were applied for carrying out technological tests of tangential static flexion, parallel compression, tangential parallel shear, radial parallel shear, tangential impact, and radial impact in the wood of Brosimum rubescens Taub. (Moraceae) coming from Leticia, state of Amazonas, Colombia. The statistical analysis was made based on the arithmetic mean, the standard deviation and the variation coefficient to obtain representativeness. Results were adjusted to 12% of content of humidity. The mechanical properties of the wood were also classified, and its possible uses determined. The wood of B. rubescens exhibited the best response to the static flexion effort. According to the ASTM classification, the elasticity module (MOE) and the Maximum Unitary Effort corresponded to the Very High range, while the Proportional Limit Effort to the Middle range. The Maximum Unitary Effort and Proportional Limit Effort obtained for the parallel compression were assigned to the High and Medium ranges, respectively, while the tangential shear matched the High range. The less favorable response was found for the radial shear effort and the impact in the tangential and radial planes that corresponded to the Medium range. It was found that the most appropriate uses of the wood were: interior finishes, external finishes, athletic and sport articles, hand crafts, ends for tools, joinery, furniture, chassis, piles, musical instruments, construction, arches for violin and similar musical instruments, breeches for weapons, structures, mischievous, keels, floors and beams.

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.

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.

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

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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.

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.

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.

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

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

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

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.

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

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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.

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

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

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

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

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)

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.

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.

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.

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

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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.

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

A Holistic Approach to Managing Microalgae for Biofuel Applications

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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.

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.

Production of biofuels obtained from microalgae

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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.

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

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

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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.

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)

Microalgae Isolation and Selection for Prospective Biodiesel Production

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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.

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.

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

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...

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.

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...

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

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.

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.

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

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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.

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.

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.

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.

Biodiesel production from microalgal isolates of southern Pakistan and quantification of FAMEs by GC-MS/MS analysis

Directory of Open Access Journals (Sweden)

Musharraf Syed

2012-12-01

Full Text Available Abstract Background Microalgae have attracted major interest as a sustainable source for biodiesel production on commercial scale. This paper describes the screening of six microalgal species, Scenedesmus quadricauda, Scenedesmus acuminatus, Nannochloropsis sp., Anabaena sp., Chlorella sp. and Oscillatoria sp., isolated from fresh and marine water resources of southern Pakistan for biodiesel production and the GC-MS/MS analysis of their fatty acid methyl esters (FAMEs. Results Growth rate, biomass productivity and oil content of each algal species have been investigated under autotrophic condition. Biodiesel was produced from algal oil by acid catalyzed transesterification reaction and resulting fatty acid methyl esters (FAMEs content was analyzed by GC/MS. Fatty acid profiling of the biodiesel, obtained from various microalgal oils showed high content of C-16:0, C-18:0, cis-Δ9C-18:1, cis-Δ11C-18:1 (except Scenedesmus quadricauda and 10-hydroxyoctadecanoic (except Scenedesmus acuminatus. Absolute amount of C-14:0, C-16:0 and C-18:0 by a validated GC-MS/MS method were found to be 1.5-1.7, 15.0-42.5 and 4.2-18.4 mg/g, respectively, in biodiesel obtained from various microalgal oils. Biodiesel was also characterized in terms of cetane number, kinematic viscosity, density and higher heating value and compared with the standard values. Conclusion Six microalgae of local origin were screened for biodiesel production. A method for absolute quantification of three important saturated fatty acid methyl esters (C-14, C-16 and C-18 by gas chromatography-tandem mass spectrometry (GC-MS/MS, using multiple reactions monitoring (MRM mode, was employed for the identification and quantification of biodiesels obtained from various microalgal oils. The results suggested that locally found microalgae can be sustainably harvested for the production of biodiesel. This offers the tremendous economic opportunity for an energy-deficient nation.

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.

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.

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.

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...

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

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

Transgene Expression in Microalgae-From Tools to Applications.

Science.gov (United States)

Doron, Lior; Segal, Na'ama; Shapira, Michal

2016-01-01

Microalgae comprise a biodiverse group of photosynthetic organisms that reside in water sources and sediments. The green microalgae Chlamydomonas reinhardtii was adopted as a useful model organism for studying various physiological systems. Its ability to grow under both photosynthetic and heterotrophic conditions allows efficient growth of non-photosynthetic mutants, making Chlamydomonas a useful genetic tool to study photosynthesis. In addition, this green alga can grow as haploid or diploid cells, similar to yeast, providing a powerful genetic system. As a result, easy and efficient transformation systems have been developed for Chlamydomonas, targeting both the chloroplast and nuclear genomes. Since microalgae comprise a rich repertoire of species that offer variable advantages for biotech and biomed industries, gene transfer technologies were further developed for many microalgae to allow for the expression of foreign proteins of interest. Expressing foreign genes in the chloroplast enables the targeting of foreign DNA to specific sites by homologous recombination. Chloroplast transformation also allows for the introduction of genes encoding several enzymes from a complex pathway, possibly as an operon. Expressing foreign proteins in the chloroplast can also be achieved by introducing the target gene into the nuclear genome, with the protein product bearing a targeting signal that directs import of the transgene-product into the chloroplast, like other endogenous chloroplast proteins. Integration of foreign genes into the nuclear genome is mostly random, resulting in large variability between different clones, such that extensive screening is required. The use of different selection modalities is also described, with special emphasis on the use of herbicides and metabolic markers which are considered to be friendly to the environment, as compared to drug-resistance genes that are commonly used. Finally, despite the development of a wide range of transformation

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

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.

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.

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.

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.

Effect of rabdosia rubescens combined with new assistant chemotherapy on serum CA199, CEA, CA15-3 and T lymphocyte subsets in patients with breast cancer

Directory of Open Access Journals (Sweden)

Lei Xi

2018-07-01

Full Text Available Objective: To study the effects of Rabdosia rubescens combined with neoadjuvant chemotherapy on serum CA199, CEA, CA15-3 levels and T lymphocyte subsets in patients with breast cancer. Methods: A total of 70 patients with breast cancer in our hospital were enrolled as the subjects of this study. The subjects were divided into control group (n=35 and treatment group (n=35 randomly. Patients in the control group were treated with new assistant chemotherapy, while those who were in the treatment group were treated with rabdosia rubescens combined with new assistant chemotherapy. The two groups of patients were treated for 3 periods. The serum CA199, CEA, CA15-3 levels and peripheral blood CD4+, CD8+, CD4+/CD8+ cells of the two groups before and after treatment were compared. Results: There were no significantly differences among the serum CA199, CEA, CA15-3 levels and peripheral blood CD4+, CD8+, CD4+/CD8+ cells of the two groups before treatment. The serum CA199, CEA and CA15-3 levels of the two groups after treatment were significantly lower than those before treatment, besides, the serum CA199, CEA and CA15-3 levels of the treatment group were significantly lower than those of the control group. The peripheral blood CD4+, CD4+/ CD8+ cells of the control group after treatment were significantly lower than before treatment, and the peripheral blood CD4+, CD4+/CD8+ cells of the treatment group after treatment were significantly higher than those of the control group. Conclusion: Rabdosia rubescens combined with new assistant chemotherapycan can significantly reduce the serum CA199, CEA and CA15-3 levels, and improve peripheral blood CD4+, CD8+, CD4+/CD8+ levels of patients with breast cancer. It is worthy of clinical application.

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.

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

Directory of Open Access Journals (Sweden)

Laia Millach

2015-01-01

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

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 ...

Transgene expression in microalgae – from tools to applications

Directory of Open Access Journals (Sweden)

Lior eDoron

2016-04-01

Full Text Available Microalgae comprise a biodiverse group of photosynthetic organisms that reside in water sources and sediments. The green microalgae Chlamydomonas reinhardtii was adopted as a useful model organism for studying various physiological systems. Its ability to grow under both photosynthetic and heterotrophic conditions allows efficient growth of non-photosynthetic mutants, making Chlamydomonas a useful genetic tool to study photosynthesis. In addition, this green alga can grow as haploid or diploid cells, similar to yeast, providing a powerful genetic system. As a result, easy and efficient transformation systems have been developed for Chlamydomonas, targeting both the chloroplast and nuclear genomes. Since microalgae comprise a rich repertoire of species that offer variable advantages for biotech and biomed industries, gene transfer technologies were further developed for many microalgae to allow for the expression of foreign proteins of interest. Expressing foreign genes in the chloroplast enables the targeting of foreign DNA to specific sites by homologous recombination. Chloroplast transformation also allows for the introduction of genes encoding several enzymes from a complex pathway, possibly as an operon. Expressing foreign proteins in the chloroplast can also be achieved by introducing the target gene into the nuclear genome, with the protein product bearing a targeting signal that directs import of the transgene-product into the chloroplast, like other endogenous chloroplast proteins. Integration of foreign genes into the nuclear genome is mostly random, resulting in large variability between different clones, such that extensive screening is required. The use of different selection modalities is also described, with special emphasis on the use of herbicides and metabolic markers which are considered to be friendly to the environment, as compared to drug-resistance genes that are commonly used. Finally, despite the development of a wide

Successful large-scale hatchery culture of sandfish (Holothuria scabra using micro-algae concentrates as a larval food source

Directory of Open Access Journals (Sweden)

Thane A. Militz

2018-02-01

Full Text Available This paper reports methodology for large-scale hatchery culture of sandfish, Holothuria scabra, in the absence of live, cultured micro-algae. We demonstrate how commercially-available micro-algae concentrates can be incorporated into hatchery protocols as the sole larval food source to completely replace live, cultured micro-algae. Micro-algae concentrates supported comparable hatchery production of sandfish to that of live, cultured micro-algae traditionally used in large-scale hatchery culture. The hatchery protocol presented allowed a single technician to achieve production of more than 18,800 juvenile sandfish at 40 days post-fertilisation in a low-resource hatchery in Papua New Guinea. Growth of auricularia larvae fed micro-algae concentrates was represented by the equation length (μm = 307.8 × ln(day + 209.2 (R2 = 0.93 while survival over the entire 40 day hatchery cycle was described by the equation survival = 2 × day−1.06 (R2 = 0.74. These results show that micro-algae concentrates have great potential for simplifying hatchery culture of sea cucumbers by reducing infrastructural and technical resources required for live micro-algae culture. The hatchery methodology described in this study is likely to have applicability to low-resource hatcheries throughout the Indo-Pacific and could support regional expansion of sandfish hatchery production.

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.

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.

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.

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.

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

Hazard and risk of herbicides for marine microalgae.

Science.gov (United States)

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

2014-04-01

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. Copyright © 2013 Elsevier Ltd. All rights reserved.

African Journal of Biotechnology - Vol 11, No 94 (2012)

African Journals Online (AJOL)

Comparative antimicrobial activity of clove and fennel essential oils against food borne pathogenic fungi and food spoilage bacteria · EMAIL FREE FULL TEXT ... Characterization of a newly isolated green microalga Scenedesmus sp. as a potential source of biodiesel · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

Effect of cell wall characteristics on algae nutrient digestibility in Nile tilapia (Oreochromis niloticus) and African catfish (Clarus gariepinus)

NARCIS (Netherlands)

Teuling, Emma; Schrama, Johan W.; Gruppen, Harry; Wierenga, Peter A.

2017-01-01

This study aimed to assess the effect of cell wall hardness and fish species on digestibility of unicellular sources. The gross composition, and the composition and cell wall hardness of the sources were determined for four sources. These were 3 microalgae species (Chlorella vulgaris, Scenedesmus

The Effects of Audible Sound for Enhancing the Growth Rate of Microalgae Haematococcus pluvialis in Vegetative Stage

Directory of Open Access Journals (Sweden)

Marcelinus Christwardana

2017-07-01

Full Text Available Physico-stimulant like audible sound is one of the new promising methods for enhancing microalgae growth rate. Here, microalgae Haematococcus pluvialis was cultivated with the addition of audible sound with titles “Blues for Elle” and “Far and Wide.” The objective of this research was to evaluate the effect of audible sound to the growth and productivity of microalgae. The experiment has been conducted by exposing the audible sound for 8 h in 22 days to microalgae cultivation. The result showed that microalgae H. pluvialis treated by the music “Blues for Elle” shows the highest growth rate (0.03 per day, and 58% higher than the one without audible sound. The average number of cells in stationary phase is 0.76 × 104 cells/mL culture and the productivity is 3.467 × 102 cells/mL/day. The pH of microalgae medium slightly decreases because of proton production during photosynthesis process. The kinetic rate constant (kapp is 0.078 per day, reaction half-life (t1/2 is 8.89 days, and catalytic surface (Ksurf is 1.66 × 10−5/day/cm2. In conclusion, this audible sound is very useful to stimulate microalgae growth rate, especially H. pluvialis.

Genetic engineering: a promising tool to engender physiological, biochemical and molecular stress resilience in green microalgae

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Freddy eGuiheneuf

2016-03-01

Full Text Available As we march into the 21st century, the prevailing scenario of depleting energy resources, global warming and ever increasing issues of human health and food security will quadruple. In this context, genetic and metabolic engineering of green microalgae complete the quest towards a continuum of environmentally clean fuel and food production. Evolutionarily related, but unlike land plants, microalgae need nominal land or water, and are best described as unicellular autotrophs using light energy to fix atmospheric CO2 into algal biomass, mitigating fossil CO2 pollution in the process. Remarkably, a feature innate to most microalgae is synthesis and accumulation of lipids (60–65% of dry weight, carbohydrates and secondary metabolites like pigments and vitamins, especially when grown under abiotic stress conditions. Particularly fruitful, such an application of abiotic stress factors like nitrogen starvation , salinity, heat shock etc. can be used in a biorefinery concept for production of multiple valuable products. The focus of this mini-review underlies metabolic reorientation practices and tolerance mechanisms as applied to green microalgae under specific stress stimuli for a sustainable pollution-free future. Moreover, we entail current progress on genetic engineering as a promising tool to grasp adaptive processes for improving strains with potential biotechnological interests.

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

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

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

Micro-algae: French players discuss the matter

International Nuclear Information System (INIS)

Bouveret, T.

2013-01-01

About 75000 species of algae have been reported so far, the domains of application are huge and investment are increasing all around the world. One of the difficulties is to find the most appropriate algae to a specific application. Some development programs have failed scientifically or economically for instance the production of protein for animal food from the chlorella algae or the production of bio-fuel from C14-C18 chains, from zeaxanthine and from phycoerytrine. On the other side some research programs have led to promising industrial applications such as the production of food for fish and farm animals. Some research fields are completely innovative such as the use of micro-algae for the construction of bio-walls for buildings. Micro-algae are diverse and fragile. Photo-bioreactors have been designed to breed fragile algae like some types of chlorophycees used in bio-fuel and in cosmetics, a prototype has been tested for 15 months and its production is about 2 kg of dry matter a day. (A.C.)

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

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.)

Resíduos madeireiros do alburno de pau-rainha (Brosimum rubescens: investigação de metabólitos secundários e alguns aspectos tecnológicos Residues of sapwood of "pau-rainha" (Brosimum rubescens: investigation of secondary metabolites and some technological aspects

Directory of Open Access Journals (Sweden)

Willian Hayasida

2011-01-01

Full Text Available Estudos fitoquímicos prévios com resíduos do cerne de pau-rainha (Brosimum rubescens, identificaram um alto teor de xantiletina, uma cumarina com potencial biológico. Dando prosseguimento aos estudos com serragens desta espécie, este estudo relata a densidade básica bem como o isolamento e identificação do triterpeno 3β-acetoxi-olean-12-eno-28-al e do β- sitosterol nos extratos hexânico e metanólico do alburno da planta. A estrutura do triterpeno foi determinada com base nos espectros de RMN em 1D (¹H e 13C e 2D (HSQC e HMBC além de comparação com dados da literatura. A densidade básica encontrada para o alburno foi de 0,58 g cm-3 que, embora seja inferior a do cerne, poderá ser utilizada na confecção de vários produtos, inclusive em técnicas de marchetaria.Previous phytochemical studies on residues of pau-rainha’s heartwood (Brosimum rubescens showed a high content of xanthyletin, a coumarin with biological potential. Continuing our studies with sawdust of this species, this work relates the basic density, isolation and identification of the triterpene 3β-acetoxy-olean-12-ene-28-al and β-sitosterol in n-hexane and MeOH extracts of the plant´s sapwood. The structure of the triterpene was determined on the basis of NMR spectra in 1D (¹H and 13C and 2D (HSQC and HMBC and comparison with literature data. The basic density found for sapwood was 0.58 g cm-3, that even so is inferior the one of heartwood, could be used in the confection of some products, also in marquetry techniques.

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.

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

A cost analysis of microalgal biomass and biodiesel production in open raceways treating municipal wastewater and under optimum light wavelength.

Science.gov (United States)

Kang, Zion; Kim, Byung-Hyuk; Ramanan, Rishiram; Choi, Jong-Eun; Yang, Ji-Won; Oh, Hee-Mock; Kim, Hee-Sik

2015-01-01

Open raceway ponds are cost-efficient for mass cultivation of microalgae compared with photobioreactors. Although low-cost options like wastewater as nutrient source is studied to overcome the commercialization threshold for biodiesel production from microalgae, a cost analysis on the use of wastewater and other incremental increases in productivity has not been elucidated. We determined the effect of using wastewater and wavelength filters on microalgal productivity. Experimental results were then fitted into a model, and cost analysis was performed in comparison with control raceways. Three different microalgal strains, Chlorella vulgaris AG10032, Chlorella sp. JK2, and Scenedesmus sp. JK10, were tested for nutrient removal under different light wavelengths (blue, green, red, and white) using filters in batch cultivation. Blue wavelength showed an average of 27% higher nutrient removal and at least 42% higher chemical oxygen demand removal compared with white light. Naturally, the specific growth rate of microalgae cultivated under blue wavelength was on average 10.8% higher than white wavelength. Similarly, lipid productivity was highest in blue wavelength, at least 46.8% higher than white wavelength, whereas FAME composition revealed a mild increase in oleic and palmitic acid levels. Cost analysis reveals that raceways treating wastewater and using monochromatic wavelength would decrease costs from 2.71 to 0.73 $/kg biomass. We prove that increasing both biomass and lipid productivity is possible through cost-effective approaches, thereby accelerating the commercialization of low-value products from microalgae, like biodiesel.

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.

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.

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.

Detection of viability of micro-algae cells by optofluidic hologram pattern.

Science.gov (United States)

Wang, Junsheng; Yu, Xiaomei; Wang, Yanjuan; Pan, Xinxiang; Li, Dongqing

2018-03-01

A rapid detection of micro-algae activity is critical for analysis of ship ballast water. A new method for detecting micro-algae activity based on lens-free optofluidic holographic imaging is presented in this paper. A compact lens-free optofluidic holographic imaging device was developed. This device is mainly composed of a light source, a small through-hole, a light propagation module, a microfluidic chip, and an image acquisition and processing module. The excited light from the light source passes through a small hole to reach the surface of the micro-algae cells in the microfluidic chip, and a holographic image is formed by the diffraction light of surface of micro-algae cells. The relation between the characteristics in the hologram pattern and the activity of micro-algae cells was investigated by using this device. The characteristics of the hologram pattern were extracted to represent the activity of micro-algae cells. To demonstrate the accuracy of the presented method and device, four species of micro-algae cells were employed as the test samples and the comparison experiments between the alive and dead cells of four species of micro-algae were conducted. The results show that the developed method and device can determine live/dead microalgae cells accurately.

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

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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.

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

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.

A Novel Enclosed Online Control System for Microalgae Production

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Bin Li

2014-03-01

Full Text Available Microalgae are single celled microscopic organisms which, like plants, convert solar energy into bio-energy through photosynthesis. They can be used to produce a variety of bio-based products, such as bio-food and biodiesel. Large scale algae production can be achieved in open or closed systems. An enclosed online microalgae control production system is presented in this paper. The designed system is composed of a reactor which is placed inside a box with light reflecting surface. Lighting system, CO2 supply, heating, as well as online cell mass monitoring via spectrophotometer, were integrated. The online monitoring of cell mass concentration is coupled to two pumps which remove a certain amount of cell suspension, and take fresh media as an alternative. Also, a LabView program was developed to collect data from a spectrophotometer and processed in a computer. Considering the limited experimental conditions and the pollution possibility for its high productivity if liquid is not properly disposed, food color was used to test the designed novel system in this paper. The results showed that, the system could detect a change in absorption over time with periodic sampling for every 4.8 minutes. When absorption value reach a pre-set gate, pump1 immediately starts to pump out a certain amount of solution?then pump2 starts to pump in fresh media according to the calculated time. The concentration could be controlled below the threshold value. From the continuous test using food color, the designed system showed good stability and controlling accuracy. It provides a good reference for the following microalgae testing experiment in future. Considering the applications of microalgae in agriculture, this research also provides resources for bio-fertilizer.

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.

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

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.

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.

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.

Growth and lipid accumulation of microalgae from fluctuating brackish and sea water locations in South East Queensland – Australia

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Van Thang eDuong

2015-05-01

Full Text Available One challenge constraining the use of microalgae in the food and biofuels industry is growth and lipid accumulation. Microalgae with high growth characteristics are more likely to originate from the local environment. However, to be commercially effective, in addition to high growth microalgae must also have high lipid productivities and contain the desired fatty acids for their intended use. We isolated microalgae from intertidal locations in South East Queensland, Australia with adverse or fluctuating conditions, as these may harbor more opportunistic strains with high lipid accumulation potential. Screening was based on a standard protocol using growth rate and lipid accumulation as well as prioritizing fatty acid profiles suitable for biodiesel or nutraceuticals. Using these criteria, an initial selection of over 50 local microalgae strains from brackish and sea water was reduced to 16 strains considered suitable for further investigation. Among these 16 strains, the ones most likely to be effective for biodiesel feedstock were Nitzschia sp. CP3a, Tetraselmis sp. M8, Cymbella sp. CP2b and Cylindrotheca closterium SI1c, reaching growth rates of up to 0.53 day-1 and lipid productivities of 5.62 µg mL-1day-1. Omega-3 fatty acids were found in some strains such as Nitzschia sp. CP2a, Nitzschia sp. CP3a and Cylindrotheca closterium SI1c. These strains have potential for further research as commercial food supplements.

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.

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.

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.

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

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

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 ...

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.

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.

Flotation: A promising microalgae harvesting and dewatering technology for biofuels production.

Science.gov (United States)

Ndikubwimana, Theoneste; Chang, Jingyu; Xiao, Zongyuan; Shao, Wenyao; Zeng, Xianhai; Ng, I-Son; Lu, Yinghua

2016-03-01

Microalgal biomass as renewable energy source is believed to be of great potential for reliable and sustainable biofuels production. However, microalgal biomass production is pinned by harvesting and dewatering stage thus hindering the developing and growing microalgae biotechnology industries. Flotation technology applied in mineral industry could be potentially applied in microalgae harvesting and dewatering, however substantial knowledge on different flotation units is essential. This paper presents an overview on different flotation units as promising cost-effective technologies for microalgae harvesting thus bestowing for further research in development and commercialization of microalgae based biofuels. Dispersed air flotation was found to be less energy consuming. Moreover, Jameson cell flotation and dispersed ozone flotation are believed to be energy efficient microalgae flotation approaches. Microalgae harvesting and dewatering by flotation is still at embryonic stage, therefore extended studies with the focus on life cycle assessment, sustainability of the flotation unit, optimization of the operating parameters using different algal species is imperative. Though there are a number of challenges in microalgae harvesting and dewatering, with well designed and developed cultivation, harvesting/dewatering, extraction and conversion technologies, progressively, microalgae technology will be of great potential for biological carbon sequestration, biofuels and biochemicals production. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Potential of microalgae in the bioremediation of water with chloride content.

Science.gov (United States)

Ramírez, M E; Vélez, Y H; Rendón, L; Alzate, E

2017-10-23

In this work it was carried out the bioremediation of water containing chlorides with native microalgae (MCA) provided by the Centre for study and research in biotechnology (CIBIOT) at Universidad Pontificia Bolivariana. Microalgae presented an adaptation to the water and so the conditions evaluated reaching a production of CO2 in mg L-1 of 53.0, 26.6, 56.0, 16.0 and 30.0 and chloride removal efficiencies of 16.37, 26.03, 40.04, 25.96 and 20.25% for microalgae1, microalgae2, microalgae3, microalgae4 and microalgae5 respectively. Water bioremediation process was carried out with content of chlorides in fed batch system with an initial concentration of chlorides of 20585 mg L-1 every 2 days. The Manipulated variables were: the flow of MCA3 (10% inoculum) for test one; NPK flow for test two, and flow of flow of MCA3+0.5 g L-1 NPK. Chloride removal efficiencies were 66.88%, 63.41% and 66.98% for test one, two and three respectively, for a total bioprocess time of 55 days.

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.

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.

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.

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.

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

Bioelectricity Production from Microalgae-Microbial Fuel Cell Technology (MMFC

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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.

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

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 ...

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.

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

Science.gov (United States)

Luo, Xuan; Su, Peng; Zhang, Wei

2015-01-01

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. PMID:26184233

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.

Potential of microalgae in the bioremediation of water with chloride content

Directory of Open Access Journals (Sweden)

M. E. Ramírez

2017-10-01

Full Text Available Abstract In this work it was carried out the bioremediation of water containing chlorides with native microalgae (MCA provided by the Centre for study and research in biotechnology (CIBIOT at Universidad Pontificia Bolivariana. Microalgae presented an adaptation to the water and so the conditions evaluated reaching a production of CO2 in mg L-1 of 53.0, 26.6, 56.0, 16.0 and 30.0 and chloride removal efficiencies of 16.37, 26.03, 40.04, 25.96 and 20.25% for microalgae1, microalgae2, microalgae3, microalgae4 and microalgae5 respectively. Water bioremediation process was carried out with content of chlorides in fed batch system with an initial concentration of chlorides of 20585 mg L-1 every 2 days. The Manipulated variables were: the flow of MCA3 (10% inoculum for test one; NPK flow for test two, and flow of flow of MCA3+0.5 g L-1 NPK. Chloride removal efficiencies were 66.88%, 63.41% and 66.98% for test one, two and three respectively, for a total bioprocess time of 55 days.

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

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.

Analysis of microalgae pellets combustion in a circulating fluidized-bed

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Kosowska-Golachowska Monika

2017-01-01

Full Text Available Microalgae are expected to become an important source of highvalue products with several applications in a large number of areas of biotechnology and, especially, in biofuels production. The increasing interest in microalgae as a source of biofuel (so-called third generation biofuel is due to the several advantages. The objective of this study was to investigate combustion characteristics of microalgae (Oscillatoria sp. pellets burnt in a circulating fluidized-bed (CFB in terms of sample temperature profiles, ignition time, ignition temperature, devolatilization time and the burnout time. Spherical 10-mm microalgae pellets were tested at temperature of 850°C in a 12-kW bench-scale CFB combustor.

Development of microalgae biomaterials with enhanced antioxidant activity using electron beam

Energy Technology Data Exchange (ETDEWEB)

Kim, Younghwa; Park, Hyunjin; Choi, Soojeong; Lee, Jaehwa [Silla Univ., Busan (Korea, Republic of)

2013-07-01

By increasing the antioxidant products (e. g. antioxidant enzyme, carotenoid, phycobiliproteins, chlorophyll, lipid phenolic compounds, etc.) in microalgae, it could be useful for industry. In this study, mutants of fresh water microalgae Arthrospira platensis (A. platensis) by high energy electron beam were isolated and characterized. Those selected mutants showed higher growth rate than parental strain. The antioxidant enzyme activity (SOD and POD), flavonoid, phenolic compound and phycocyanin of mutants were increased about 2 times compared to wild type. Moreover, DPPH radical scavenging activity was increased about 20%. Microalgae species with improved growth rate and enhanced active compounds make the commercial process more feasible in industry. Using microalgae mutants with increased antioxidant products, it is useful to develop microalgae biomaterials for neutraceuticals.

Development of microalgae biomaterials with enhanced antioxidant activity using electron beam

International Nuclear Information System (INIS)

Kim, Younghwa; Park, Hyunjin; Choi, Soojeong; Lee, Jaehwa

2013-01-01

By increasing the antioxidant products (e. g. antioxidant enzyme, carotenoid, phycobiliproteins, chlorophyll, lipid phenolic compounds, etc.) in microalgae, it could be useful for industry. In this study, mutants of fresh water microalgae Arthrospira platensis (A. platensis) by high energy electron beam were isolated and characterized. Those selected mutants showed higher growth rate than parental strain. The antioxidant enzyme activity (SOD and POD), flavonoid, phenolic compound and phycocyanin of mutants were increased about 2 times compared to wild type. Moreover, DPPH radical scavenging activity was increased about 20%. Microalgae species with improved growth rate and enhanced active compounds make the commercial process more feasible in industry. Using microalgae mutants with increased antioxidant products, it is useful to develop microalgae biomaterials for neutraceuticals

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

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...

Potential of microalgae in the bioremediation of water with chloride content

OpenAIRE

Ramírez, M. E.; Vélez, Y. H.; Rendón, L.; Alzate, E.

2017-01-01

Abstract In this work it was carried out the bioremediation of water containing chlorides with native microalgae (MCA) provided by the Centre for study and research in biotechnology (CIBIOT) at Universidad Pontificia Bolivariana. Microalgae presented an adaptation to the water and so the conditions evaluated reaching a production of CO2 in mg L-1 of 53.0, 26.6, 56.0, 16.0 and 30.0 and chloride removal efficiencies of 16.37, 26.03, 40.04, 25.96 and 20.25% for microalgae1, microalgae2, microalg...

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...

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

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

Effective cultivation of microalgae for biofuel production: a pilot-scale evaluation of a novel oleaginous microalga Graesiella sp. WBG-1.

Science.gov (United States)

Wen, Xiaobin; Du, Kui; Wang, Zhongjie; Peng, Xinan; Luo, Liming; Tao, Huanping; Xu, Yan; Zhang, Dan; Geng, Yahong; Li, Yeguang

2016-01-01

Commercial production of microalgal biodiesel is not yet economically viable, largely because of low storage lipid yield in microalgae mass cultivation. Selection of lipid-rich microalgae, thus, becomes one of the key research topics for microalgal biodiesel production. However, the laboratory screening protocols alone cannot predict the ability of the strains to dominate and perform in outdoor ponds. Comprehensive assessment of microalgae species should be performed not only under the laboratory conditions, but also in the fields. Laboratory investigations using a bubbled column photobioreactor indicated the microalga Graesiella sp. WBG-1 to be the most productive species among the 63 Chlorophyta strains. In a 10 L reactor, mimicking the industrial circular pond, Graesiella sp. WBG-1 produced 12.03 g biomass m(-2) day(-1) and 5.44 g lipids (45.23 % DW) m(-2) day(-1) under 15 mol m(-2) day(-1) artificial light irradiations. The lipid content decreased to ~34 % DW when the microalga was cultured in 30 L tank PBR under natural solar irradiations, but the decline of lipid content with scaling up was the minimum among the tested strains. Based on these results, the microalga was further tested for its lipid production and culture competitiveness using a pilot-scale raceway pond (200 m(2) illuminated area, culture volume 40,000 L). Consequently, Graesiella sp. WBG-1 maintained a high lipid content (33.4 % DW), of which ~90 % was storage TAGs. Results from the outdoor experiments indicated the nice adaptability of the Graesiella sp. WBG-1 to strong and fluctuating natural solar irradiance and temperature, and also demonstrated several other features, such as large cell size (easy for harvest and resistant to swallow by protozoa) and tolerance to high culture pH (helpful to CO2 fixation). Graesiella sp. WBG-1 was a promising strain capable of accumulating large amount of storage lipid under nature solar irradiance and temperature. The high lipid content

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.

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.

Wastewater nutrient removal in a mixed microalgae-bacteria culture: effect of light and temperature on the microalgae-bacteria competition.

Science.gov (United States)

González-Camejo, J; Barat, R; Pachés, M; Murgui, M; Seco, A; Ferrer, J

2018-02-01

The aim of this study was to evaluate the effect of light intensity and temperature on nutrient removal and biomass productivity in a microalgae-bacteria culture and their effects on the microalgae-bacteria competition. Three experiments were carried out at constant temperature and various light intensities: 40, 85 and 125 µE m -2  s -1 . Other two experiments were carried out at variable temperatures: 23 ± 2°C and 28 ± 2°C at light intensity of 85 and 125 µE m -2  s -1 , respectively. The photobioreactor was fed by the effluent from an anaerobic membrane bioreactor. High nitrogen and phosphorus removal efficiencies (about 99%) were achieved under the following operating conditions: 85-125 µE m -2  s -1 and 22 ± 1°C. In the microalgae-bacteria culture studied, increasing light intensity favoured microalgae growth and limited the nitrification process. However, a non-graduated temperature increase (up to 32°C) under the light intensities studied caused the proliferation of nitrifying bacteria and the nitrite and nitrate accumulation. Hence, light intensity and temperature are key parameters in the control of the microalgae-bacteria competition. Biomass productivity significantly increased with light intensity, reaching 50.5 ± 9.6, 80.3 ± 6.5 and 94.3 ± 7.9 mgVSS L -1  d -1 for a light intensity of 40, 85 and 125 µE m -2  s -1 , respectively.

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

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...

Biotechnological production of value-added carotenoids from microalgae: Emerging technology and prospects.

Science.gov (United States)

Wichuk, Kristine; Brynjólfsson, Sigurður; Fu, Weiqi

2014-01-01

We recently evaluated the relationship between abiotic environmental stresses and lutein biosynthesis in the green microalga Dunaliella salina and suggested a rational design of stress-driven adaptive evolution experiments for carotenoids production in microalgae. Here, we summarize our recent findings regarding the biotechnological production of carotenoids from microalgae and outline emerging technology in this field. Carotenoid metabolic pathways are characterized in several representative algal species as they pave the way for biotechnology development. The adaptive evolution strategy is highlighted in connection with enhanced growth rate and carotenoid metabolism. In addition, available genetic modification tools are described, with emphasis on model species. A brief discussion on the role of lights as limiting factors in carotenoid production in microalgae is also included. Overall, our analysis suggests that light-driven metabolism and the photosynthetic efficiency of microalgae in photobioreactors are the main bottlenecks in enhancing biotechnological potential of carotenoid production from microalgae.

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.

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...

Review of Microalgae Harvesting via Co-Pelletization with Filamentous Fungus

Directory of Open Access Journals (Sweden)

Bo Hu

2013-11-01

Full Text Available Cultivation of microalgae to utilize CO2 and nutrients in the wastewater to generate biofuel products is a promising research objective. However, the process faces tremendous technical difficulties, especially the harvest of microalgae cells, an economically challenging step. Several researchers recently reported co-culturing of filamentous fungi with microalgae so that microalgae cells can be co-pelletized in order to facilitate the cell harvest. This algae pelletization via the filamentous fungi represents an innovative approach to address both the cost and sustainability issues in algae biofuel production and also has potential with direct commercial applications. This paper reviews the current research status in this area and some possible drawbacks of this method in order to provide some possible directions for the future research.

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

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,

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)

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....

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

[Progress in microalgae culture system for biodiesel combined with reducing carbon dioxide emission].

Science.gov (United States)

Su, Hongyang; Zhou, Xuefei; Xia, Xuefen; Sun, Zhen; Zhang, Yalei

2011-09-01

Wastewater resources, CO2 emission reduction and microalgae biodiesel are considered as current frontier fields of energy and environmental researches. In this paper, we reviewed the progress in system of microalgae culture for biodiesel production by wastewater and stack gas. Multiple factors including microalgal species, nutrition, culture methods and photobioreactor, which were crucial to the cultivation of microalgae for biodiesel production, were discussed in detail. A valuable culture system of microalgae for biodiesel production or other high value products combined with the treatment of wastewater by microalgae was put forward through the optimizations of algal species and culture technology. The culture system coupled with the treatment of wastewater, the reduction of CO2 emission with the cultivation of microalgae for biodiesel production will reduce the production cost of microalgal biofuel production and the treatment cost of wastewater simultaneously. Therefore, it would be a promising technology with important environmental value, social value and economic value to combine the treatment of wastewater with the cultivation of microalgae for biodiesel production.

The Potential Use of Marine Microalgae and Cyanobacteria in Cosmetics and Thalassotherapy

Directory of Open Access Journals (Sweden)

M. Lourdes Mourelle

2017-11-01

Full Text Available The use of microalgae and cyanobacteria for nutritional purposes dates back thousands of years; during the last few decades, microalgae culture has improved to become one of the modern biotechnologies. This has allowed high amounts of algal biomass to be obtained for use in different applications. Currently, the global production of microalgae and cyanobacteria is predominately aimed at applications with high added value given that algal biomass contains pigments, proteins, essential fatty acids, polysaccharides, vitamins, and minerals, all of which are of great interest in the preparation of natural products, both as food and in cosmetics. Hence, the bioactive components from microalgae can be incorporated in cosmetic and cosmeceutical formulations, and can help achieve benefits including the maintenance of skin structure and function. Thalassotherapy involves using seawater and all related marine elements, including macroalgae, however, there has been limited use of microalgae. Microalgae and cyanobacteria could be incorporated into health and wellness treatments applied in thalassotherapy centers due to their high concentration of biologically active substances that are of interest in skin care. This paper briefly reviews the current and potential cosmetic and cosmeceutical applications of marine microalgae and cyanobacteria compounds and also recommends its use in thalassotherapy well-being treatments.

Bionota: Bacterias promotoras de crecimiento de microalgas: una nueva aproximación en el tratamiento de aguas residuales Microalgae growth-promoting bacteria: A novel approach in wastewater treatment

Directory of Open Access Journals (Sweden)

Bashan Yoav

2003-12-01

Full Text Available Las bacterias promotoras de crecimiento en plantas (PGPB del género Azospirillum son conocidas porque mejo­ran el crecimiento de numerosas cosechas agrícolas; sin embargo, el presente trabajo pretende extender el uso de estas bacterias a "bacterias promotoras de crecimiento de microalgas" (MPGB para aumentar la capacidad de las microalgas de eliminar nutrientes de aguas residuales. La inoculación deliberada de las microalgas Chlorella spp. con PGPB de origen terrestre no ha sido reportada con anterioridad, tal vez debido al origen diferente de estos dos microorganismos. Al inmovilizar de manera conjunta Chlorella vulgaris y Azospirillum brasilense Cd en esferas de alginato, se obtuvo como resultado un aumento significativo en varios parámetros de crecimiento de la microalga, como el peso fresco y seco, el número total de células, el tamaño de las colonias de microalgas dentro de la esfera, el número de organismos por colonia y la concentración de pigmentos. Además, aumenta­ron los lípidos y la variedad de ácidos grasos. La microalga combinada con la MGPB tiene una mayor capacidad de eliminar amonio y fósforo tanto en agua residual sintética como en agua residual doméstica. Actualmente se ha estado experimentando con otras PGPB (Flavobacterium sp. Azospirillum sp. y Azotobacter sp. para propósitos acuícolas; por ejemplo aumentar el crecimiento de fitoplancton utilizado en el cultivo de carpas y estabilizar cultivos masivos de microalgas marinas utilizadas como alimento para organismos marinos, todo esto con resul­tados promisorios. Si bien el efecto de las PGPB en microorganismos acuáticos aún no ha sido suficientemente explorado, proponemos que la co-inmovilización de microalgas y bacterias promotoras de crecimiento es un medio efectivo para aumentar la población microalgal y también su capacidad de limpiar aguas residuales. Palabras clave: PGPB; microalgas; biotratamiento de aguas residuales; co

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.

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...

Anaerobic digestion of microalgae residues resulting from the biodiesel production process

International Nuclear Information System (INIS)

Ehimen, E.A.; Sun, Z.F.; Carrington, C.G.; Birch, E.J.; Eaton-Rye, J.J.

2011-01-01

The recovery of methane from post transesterified microalgae residues has the potential to improve the renewability of the 'microalgae biomass to biodiesel' conversion process as well as reduce its cost and environmental impact. This paper deals with the anaerobic digestion of microalgae biomass residues (post transesterification) using semi-continuously fed reactors. The influence of substrate loading concentrations and hydraulic retention times on the specific methane yield of the anaerobically digested microalgae residues was investigated. The co-digestion of the microalgae residues with glycerol as well as the influence of temperature was also examined. It was found that the hydraulic retention period was the most significant variable affecting methane production from the residues, with periods (>5 days) corresponding to higher energy recovery. The methane yield was also improved by a reduction in the substrate loading rates, with an optimum substrate carbon to nitrogen ratio of 12.44 seen to be required for the digestion process.

Effects of Fluctuating Environments on the Selection of High Yielding Microalgae

Energy Technology Data Exchange (ETDEWEB)

Benemann, J. R.; Tillett, D. M.

1987-02-27

Microalgae have the potential of producing biomass with a high content of lipids at high productivities using seawater or saline ground water resources. Microalgal lipids are similar to vegetable oils and suitable for processing to liquid fuels. Engineering cost analysis studies have concluded that, at a favorable site, microalgae cultivation for fuel production could be economically viable. The major uncertainties involve the microalgae themselves: biomass and lipid productivity and culture stability.

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

Microalgae growth-promoting bacteria: A novel approach in wastewater treatment

Directory of Open Access Journals (Sweden)

Luz E. de-Bashan

2003-07-01

Full Text Available Plant growth-promoting bacteria (PGPB from the genus Azospirillum are known to enhance the growth of numerous agricultural crops. The use of these bacteria is proposed as "micro-algae-growth promoting bacteria" (MGPB for enhancing freshwater micro-algae Chlorella vulgaris and C. sorokiniana capadty to clean polluted water. The deliberate inoculation of Chlorella sp. with a terrestrial PGPB has not been reported prior to these studies, perhaps because of the different origin of the two micro-organisms. Chlorella spp. is not known to harbour any plant growth-promoting bacteria and Azospirillum sp. is rarely used for inoculation in aquatic environments. Co-immobilisation of C. vulgaris and A. brasilense Cd in small alginate beads resulted in significant increases in numerous micro-algae growth parameters. Dry and fresh weight, total number of cells, micro-algal cluster (colonies size within the bead, number of micro-algal cells per cluster and micro-algal pigments levels significantly increased. Lipids and the variety of fatty adds also significantly increased, as did the combination of micro-algae. MGPB had superior capacity for removing ammonium and phosphorus from polluted synthetic and municipal wastewaters than the micro-algae by itself. Other PGPB (i.e. Flavobacterium sp. Azospirillum sp. and Azotobacter sp. are currently being tested in aquaculture; carp farming using enhanced phytoplankton growth and stabilising mass marine micro-algae culture for use as feed for marine organisms are both retuming promising results. This aspect of PGPB effect on water micro-organisms is currently in its infancy. We pro pose that co-immobilising micro-algae and plant growth-promoting bacteria represent an effective means of increasing micro-algal populations and also their capacity for cleaning polluted water. Key words: PGPB; micro-algae; wastewater treatment; co-immobilised

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.

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

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.

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.

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.

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.

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.

Combining and Comparing Coalescent, Distance and Character-Based Approaches for Barcoding Microalgaes: A Test with Chlorella-Like Species (Chlorophyta.

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Shanmei Zou

Full Text Available Several different barcoding methods of distinguishing species have been advanced, but which method is the best is still controversial. Chlorella is becoming particularly promising in the development of second-generation biofuels. However, the taxonomy of Chlorella-like organisms is easily confused. Here we report a comprehensive barcoding analysis of Chlorella-like species from Chlorella, Chloroidium, Dictyosphaerium and Actinastrum based on rbcL, ITS, tufA and 16S sequences to test the efficiency of traditional barcoding, GMYC, ABGD, PTP, P ID and character-based barcoding methods. First of all, the barcoding results gave new insights into the taxonomic assessment of Chlorella-like organisms studied, including the clear species discrimination and resolution of potentially cryptic species complexes in C. sorokiniana, D. ehrenbergianum and C. Vulgaris. The tufA proved to be the most efficient barcoding locus, which thus could be as potential "specific barcode" for Chlorella-like species. The 16S failed in discriminating most closely related species. The resolution of GMYC, PTP, P ID, ABGD and character-based barcoding methods were variable among rbcL, ITS and tufA genes. The best resolution for species differentiation appeared in tufA analysis where GMYC, PTP, ABGD and character-based approaches produced consistent groups while the PTP method over-split the taxa. The character analysis of rbcL, ITS and tufA sequences could clearly distinguish all taxonomic groups respectively, including the potentially cryptic lineages, with many character attributes. Thus, the character-based barcoding provides an attractive complement to coalescent and distance-based barcoding. Our study represents the test that proves the efficiency of multiple DNA barcoding in species discrimination of microalgaes.

Combining and Comparing Coalescent, Distance and Character-Based Approaches for Barcoding Microalgaes: A Test with Chlorella-Like Species (Chlorophyta)

Science.gov (United States)

Zou, Shanmei; Fei, Cong; Song, Jiameng; Bao, Yachao; He, Meilin; Wang, Changhai

2016-01-01

Several different barcoding methods of distinguishing species have been advanced, but which method is the best is still controversial. Chlorella is becoming particularly promising in the development of second-generation biofuels. However, the taxonomy of Chlorella–like organisms is easily confused. Here we report a comprehensive barcoding analysis of Chlorella-like species from Chlorella, Chloroidium, Dictyosphaerium and Actinastrum based on rbcL, ITS, tufA and 16S sequences to test the efficiency of traditional barcoding, GMYC, ABGD, PTP, P ID and character-based barcoding methods. First of all, the barcoding results gave new insights into the taxonomic assessment of Chlorella-like organisms studied, including the clear species discrimination and resolution of potentially cryptic species complexes in C. sorokiniana, D. ehrenbergianum and C. Vulgaris. The tufA proved to be the most efficient barcoding locus, which thus could be as potential “specific barcode” for Chlorella-like species. The 16S failed in discriminating most closely related species. The resolution of GMYC, PTP, P ID, ABGD and character-based barcoding methods were variable among rbcL, ITS and tufA genes. The best resolution for species differentiation appeared in tufA analysis where GMYC, PTP, ABGD and character-based approaches produced consistent groups while the PTP method over-split the taxa. The character analysis of rbcL, ITS and tufA sequences could clearly distinguish all taxonomic groups respectively, including the potentially cryptic lineages, with many character attributes. Thus, the character-based barcoding provides an attractive complement to coalescent and distance-based barcoding. Our study represents the test that proves the efficiency of multiple DNA barcoding in species discrimination of microalgaes. PMID:27092945

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

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

Phytohormones and Effects on Growth and Metabolites of Microalgae: A Review

Directory of Open Access Journals (Sweden)

Xingfeng Han

2018-04-01

Full Text Available Microalgae cultivation is booming in agriculture, aquaculture, and bioenergy sectors. A wide range of bioactive compounds with attractive properties can be produced with microalgae, including pigments, vitamins, proteins, carbohydrates, and lipids. The biofuel yields from microalgae can exceed the yields obtained with energy crops by 10–100 times. Therefore, such cultivation is promising for the regulation of the biosynthesis of microalagae with phytohormones, which can enhance the production of high-valued bioproducts. This review reports the effect of auxins, abscisic acid, cytokinins, gibberellins, and ethylene on microalgal growth and metabolites, as well as the crosstalk of different phytohormones. The use of phytohormones is also promising because it can also reduce the inputs necessary to grow the selected microalgae and maximize the yields.

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

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...

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.

A Ribbon-like Structure in the Ejective Organelle of the Green Microalga Pyramimonas parkeae (Prasinophyceae) Consists of Core Histones and Polymers Containing N-acetyl-glucosamine.

Science.gov (United States)

Yamagishi, Takahiro; Kurihara, Akira; Kawai, Hiroshi

2015-11-01

The green microalga, Pyramimonas parkeae (Prasinophyceae) has an ejective organelle containing a coiled ribbon structure resembling the ejectisome in Cryptophyta. This structure is discharged from the cell by a stimulus and extends to form a tube-like structure, but the molecular components of the structure have not been identified. Tricine-SDS-PAGE analysis indicated that the ribbon-like structure of P. parkeae contains some proteins and low molecular acidic polymers. Edman degradation, LC/MS/MS analyses and immunological studies demonstrated that their proteins are core histones (H3, H2A, H2B and H4). In addition, monosaccharide composition analysis of the ribbon-like structures and degradation by lysozyme strongly indicated that the ribbon-like structure consist of β (1-4) linked polymers containing N-acetyl-glucosamine. Purified polymers and recombinant histones formed glob-like or filamentous structures. Therefore we conclude that the ribbon-like structure of P. parkeae mainly consists of a complex of core histones (H3, H2A, H2B and H4) and polymers containing N-acetyl-glucosamine, and suggest to name the ejective organelle in P. parkeae the "histrosome" to distinguish it from the ejectisome in Cryptophyta. Copyright © 2015 Elsevier GmbH. All rights reserved.

Effect of Lignocellulose Related Compounds on Microalgae Growth and Product Biosynthesis: A Review

Directory of Open Access Journals (Sweden)

Krystian Miazek

2014-07-01

Full Text Available Microalgae contain valuable compounds that can be harnessed for industrial applications. Lignocellulose biomass is a plant material containing in abundance organic substances such as carbohydrates, phenolics, organic acids and other secondary compounds. As growth of microalgae on organic substances was confirmed during heterotrophic and mixotrophic cultivation, lignocellulose derived compounds can become a feedstock to cultivate microalgae and produce target compounds. In this review, different treatment methods to hydrolyse lignocellulose into organic substrates are presented first. Secondly, the effect of lignocellulosic hydrolysates, organic substances typically present in lignocellulosic hydrolysates, as well as minor co-products, on growth and accumulation of target compounds in microalgae cultures is described. Finally, the possibilities of using lignocellulose hydrolysates as a common feedstock for microalgae cultures are evaluated.

Efficient Anaerobic Digestion of Microalgae Biomass: Proteins as a Key Macromolecule.

Science.gov (United States)

Magdalena, Jose Antonio; Ballesteros, Mercedes; González-Fernandez, Cristina

2018-05-06

Biogas generation is the least complex technology to transform microalgae biomass into bioenergy. Since hydrolysis has been pointed out as the rate limiting stage of anaerobic digestion, the main challenge for an efficient biogas production is the optimization of cell wall disruption/hydrolysis. Among all tested pretreatments, enzymatic treatments were demonstrated not only very effective in disruption/hydrolysis but they also revealed the impact of microalgae macromolecular composition in the anaerobic process. Although carbohydrates have been traditionally recognized as the polymers responsible for the low microalgae digestibility, protease addition resulted in the highest organic matter solubilization and the highest methane production. However, protein solubilization during the pretreatment can result in anaerobic digestion inhibition due to the release of large amounts of ammonium nitrogen. The possible solutions to overcome these negative effects include the reduction of protein biomass levels by culturing the microalgae in low nitrogen media and the use of ammonia tolerant anaerobic inocula. Overall, this review is intended to evidence the relevance of microalgae proteins in different stages of anaerobic digestion, namely hydrolysis and methanogenesis.

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

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.

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.

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

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

Metabolic engineering of Cyanobacteria and microalgae for enhanced production of biofuels and high-value products.

Science.gov (United States)

Gomaa, M A; Al-Haj, L; Abed, R M M

2016-10-01

A lot of research has been performed on Cyanobacteria and microalgae with the aim to produce numerous biotechnological products. However, native strains have a few shortcomings, like limitations in cultivation, harvesting and product extraction, which prevents reaching optimal production value at lowest costs. Such limitations require the intervention of genetic engineering to produce strains with superior properties. Promising advancements in the cultivation of Cyanobacteria and microalgae have been achieved by improving photosynthetic efficiency through increasing RuBisCO activity and truncation of light-harvesting antennae. Genetic engineering has also contributed to final product extraction by inducing autolysis and product secretory systems, to enable direct product recovery without going through costly extraction steps. In this review, we summarize the different enzymes and pathways that have been targeted thus far for improving cultivation aspects, harvesting and product extraction in Cyanobacteria and microalgae. With synthetic biology advancements, genetically engineered strains can be generated to resolve demanding process issues and achieve economic practicality. This comprehensive overview of gene modifications will be useful to researchers in the field to employ on their strains to increase their yields and improve the economic feasibility of the production process. © 2016 The Society for Applied Microbiology.

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.

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.

The role of biochemical engineering in the production of biofuels from microalgae.

Science.gov (United States)

Costa, Jorge Alberto Vieira; de Morais, Michele Greque

2011-01-01

Environmental changes that have occurred due to the use of fossil fuels have driven the search for alternative sources that have a lower environmental impact. First-generation biofuels were derived from crops such as sugar cane, corn and soybean, which contribute to water scarcity and deforestation. Second-generation biofuels originated from lignocellulose agriculture and forest residues, however these needed large areas of land that could be used for food production. Based on technology projections, the third generation of biofuels will be derived from microalgae. Microalgae are considered to be an alternative energy source without the drawbacks of the first- and second-generation biofuels. Depending upon the growing conditions, microalgae can produce biocompounds that are easily converted into biofuels. The biofuels from microalgae are an alternative that can keep the development of human activity in harmony with the environment. This study aimed to present the main biofuels that can be derived from microalgae. Copyright © 2010 Elsevier Ltd. All rights reserved.

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)

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

A Method for Microalgae Proteomics Analysis Based on Modified Filter-Aided Sample Preparation.

Science.gov (United States)

Li, Song; Cao, Xupeng; Wang, Yan; Zhu, Zhen; Zhang, Haowei; Xue, Song; Tian, Jing

2017-11-01

With the fast development of microalgal biofuel researches, the proteomics studies of microalgae increased quickly. A filter-aided sample preparation (FASP) method is widely used proteomics sample preparation method since 2009. Here, a method of microalgae proteomics analysis based on modified filter-aided sample preparation (mFASP) was described to meet the characteristics of microalgae cells and eliminate the error caused by over-alkylation. Using Chlamydomonas reinhardtii as the model, the prepared sample was tested by standard LC-MS/MS and compared with the previous reports. The results showed mFASP is suitable for most of occasions of microalgae proteomics studies.

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.

Integration of microalgae cultivation with industrial waste remediation for biofuel and bioenergy production: opportunities and limitations.

Science.gov (United States)

McGinn, Patrick J; Dickinson, Kathryn E; Bhatti, Shabana; Frigon, Jean-Claude; Guiot, Serge R; O'Leary, Stephen J B

2011-09-01

There is currently a renewed interest in developing microalgae as a source of renewable energy and fuel. Microalgae hold great potential as a source of biomass for the production of energy and fungible liquid transportation fuels. However, the technologies required for large-scale cultivation, processing, and conversion of microalgal biomass to energy products are underdeveloped. Microalgae offer several advantages over traditional 'first-generation' biofuels crops like corn: these include superior biomass productivity, the ability to grow on poor-quality land unsuitable for agriculture, and the potential for sustainable growth by extracting macro- and micronutrients from wastewater and industrial flue-stack emissions. Integrating microalgal cultivation with municipal wastewater treatment and industrial CO(2) emissions from coal-fired power plants is a potential strategy to produce large quantities of biomass, and represents an opportunity to develop, test, and optimize the necessary technologies to make microalgal biofuels more cost-effective and efficient. However, many constraints on the eventual deployment of this technology must be taken into consideration and mitigating strategies developed before large scale microalgal cultivation can become a reality. As a strategy for CO(2) biomitigation from industrial point source emitters, microalgal cultivation can be limited by the availability of land, light, and other nutrients like N and P. Effective removal of N and P from municipal wastewater is limited by the processing capacity of available microalgal cultivation systems. Strategies to mitigate against the constraints are discussed.

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.

Thermogravimetric analysis of co-combustion between microalgae and textile dyeing sludge.

Science.gov (United States)

Peng, Xiaowei; Ma, Xiaoqian; Xu, Zhibin

2015-03-01

The synergistic interaction and kinetics of microalgae, textile dyeing sludge and their blends were investigated under combustion condition by thermogravimetric analysis. The textile dyeing sludge was blended with microalgae in the range of 10-90wt.% to investigate their co-combustion behavior. Results showed that the synergistic interaction between microalgae and textile dyeing sludge improved the char catalytic effect and alkali metals melt-induced effect on the decomposition of textile dyeing sludge residue at high temperature of 530-800°C. As the heating rate increasing, the entire combustion process was delayed but the combustion intensity was enhanced. The lowest average activation energy was obtained when the percentage of microalgae was 60%, which was 227.1kJ/mol by OFW and 227.4kJ/mol by KAS, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Water use and its recycling in microalgae cultivation for biofuel application.

Science.gov (United States)

Farooq, Wasif; Suh, William I; Park, Min S; Yang, Ji-Won

2015-05-01

Microalgal biofuels are not yet economically viable due to high material and energy costs associated with production process. Microalgae cultivation is a water-intensive process compared to other downstream processes for biodiesel production. Various studies found that the production of 1 L of microalgal biodiesel requires approximately 3000 L of water. Water recycling in microalgae cultivation is desirable not only to reduce the water demand, but it also improves the economic feasibility of algal biofuels as due to nutrients and energy savings. This review highlights recently published studies on microalgae water demand and water recycling in microalgae cultivation. Strategies to reduce water footprint for microalgal cultivation, advantages and disadvantages of water recycling, and approaches to mitigate the negative effects of water reuse within the context of water and energy saving are also discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

Biodiesel from wet microalgae: extraction with hexane after the microwave-assisted transesterification of lipids.

Science.gov (United States)

Cheng, Jun; Huang, Rui; Li, Tao; Zhou, Junhu; Cen, Kefa

2014-10-01

A chloroform-free novel process for the efficient production of biodiesel from wet microalgae is proposed. Crude biodiesel is produced through extraction with hexane after microwave-assisted transesterification (EHMT) of lipids in wet microalgae. Effects of different parameters, including reaction temperature, reaction time, methanol dosage, and catalyst dosage, on fatty acids methyl esters (FAMEs) yield are investigated. The yield of FAME extracted into the hexane from the wet microalgae is increased 6-fold after the transesterification of lipids. The yield of FAME obtained through EHMT of lipids in wet microalgae is comparable to that obtained through direct transesterification of dried microalgae biomass with chloroform; however, FAME content in crude biodiesel obtained through EHMT is 86.74%, while that in crude biodiesel obtained through the chloroform-based process is 75.93%. EHMT ensures that polar pigments present in microalgae are not extracted into crude biodiesel, which leads to a 50% reduction in nitrogen content in crude biodiesel. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

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.

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.

Interacción bacteria-microalga en el ambiente marino y uso potencial en acuicultura Microalgae and bacteria interaction in the aquatic environment and their potential use in aquaculture

Directory of Open Access Journals (Sweden)

CARLOS E. RIQUELME

2003-12-01

Full Text Available El presente estudio tiene como objetivo revisar el conocimiento generado sobre el rol que juegan las interacciones bacteria-microalga en ambientes marinos y dulceacuícolas, definiendo las posibles aplicaciones que puede tener el conocimiento de estas interacciones en el manejo de las aguas costeras y sistemas acuícolas. Los antecedentes proporcionados en este análisis permiten sugerir que bacterias y/o microalgas, constituyen una alternativa para el control de proliferaciones de bacterias y fitoplancton causantes de efectos dañinos en ambientes naturales y sistemas cerrados de cultivo. Además, las interacciones específicas entre bacteria-microalga permitiría la optimización de sistemas productivos en la industria acuícola. Sin embargo, los mecanismos de estas interacciones son pobremente entendidos. Futuras investigaciones debieran ser dirigidas a comprender el modo de acción de las interacciones bacteria-microalga a nivel molecularThe objective of this survey is to review the knowledge generated with respect to the role of bacteria-microalgae interaction play in marine and fresh environments, and to define the possible application of these microorganisms on the management of costal water and aquaculture systems. This review proposes that bacteria and/or microalgae are an alternative to control the proliferation of bacteria and phytoplankton that cause damages in natural environments or in closed culture systems. Also, the knowledge of specific interactions between bacteria and microalgae will allow the optimization of productive systems in aquaculture. However, until date the mechanisms involved in these interactions are poorly understood. Therefore, future investigations should be directed towards understanding the mode of action of such interactions at a molecular level

Microalgae as bioreactors for bioplastic production

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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.

Biodiesel renovável derivado de microalgas: avanços e perspectivas tecnológicas

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Claudio M. P. Pereira

2012-01-01

Full Text Available Microalgae are a promising source of raw material for biodiesel production. This review discusses the latest developments related to the application of microalgae biomass for biodiesel production. Characterization of fatty acid of microalgae and comparisons with other sources of raw materials and processes are presented. Furthermore, technological perspectives and approaches for growing microalgae in photobioreactors, microalgal oil extraction techniques, and procedures for synthesizing biodiesel are reviewed.

Biodiesel de microalgas: avanços e desafios

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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.

Chemical composition of microalgae Heterochlorella luteoviridis and Dunaliella tertiolecta with emphasis on carotenoids.

Science.gov (United States)

Diprat, Andressa Bacalau; Menegol, Tania; Boelter, Juliana Ferreira; Zmozinski, Ariane; Rodrigues Vale, Maria Goreti; Rodrigues, Eliseu; Rech, Rosane

2017-08-01

Microalgae have been used as food supplements owing to their high protein, polyunsaturated fatty acid and carotenoid contents. As different carotenoids have distinct properties and the carotenoid composition of microalgae has been poorly explored in the literature, this study determined the complete carotenoid composition of two microalgae species, Heterochlorella luteoviridis and Dunaliella tertiolecta, using high-performance liquid chromatography coupled with diode array detection and tandem mass spectrometry (HPLC-DAD/MS 2 ). Additionally, the proximate composition and major minerals were evaluated. The carotenoid composition of the two microalgae was similar, with 13 carotenoids being found in H. luteoviridis and 12 in D. tertiolecta. The major carotenoids were all-trans-lutein (1.18 mg g -1 in H. luteoviridis and 1.59 mg g -1 in D. tertiolecta), all-trans-violaxanthin (0.52 mg g -1 in H. luteoviridis and 0.45 mg g -1 in D. tertiolecta) and all-trans-β-carotene (0.50 mg g -1 in H. luteoviridis and 0.62 mg g -1 in D. tertiolecta). All-trans-lutein was the predominant carotenoid in both microalgae, representing around 40% (mass fraction) of the total carotenoids. The lutein content found in these microalgae was significantly higher (2-40 times) than that in other important food sources of lutein (e.g. parsley, carrot, red pepper and broccoli). The microalgae H. luteoviridis and D. tertiolecta are excellent sources of lutein that could be commercially exploited by the food and pharmaceutical industries. Moreover, it was confirmed that both microalgae are good sources of protein, lipids and calcium. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Protein N-glycosylation in eukaryotic microalgae and its impact on the production of nuclear expressed biopharmaceuticals

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Elodie eMathieu-Rivet

2014-07-01

Full Text Available Microalgae are currently used for the production of food compounds. Recently, few microalgae species have been investigated as potential biofactories for the production of biopharmaceuticals. Indeed in this context, microalgae are cheap, classified as Generally Recognized As Safe (GRAS organisms and can be grown easily. However, problems remain to be solved before any industrial production of microalgae-made biopharmaceuticals. Among them, post-translational modifications of the proteins need to be considered. Especially, N-glycosylation acquired by the secreted recombinant proteins is of major concern since most of the biopharmaceuticals are N-glycosylated and it is well recognized that glycosylation represent one of their critical quality attribute. Therefore, the evaluation of microalgae as alternative cell factory for biopharmaceutical productions thus requires to investigate their N-glycosylation capability in order to determine to what extend it differs from their human counterpart and to determine appropriate strategies for remodelling the microalgae glycosylation into human-compatible oligosaccharides. Here, we review the secreted recombinant proteins which have been successfully produced in microalgae. We also report on recent bioinformatics and biochemical data concerning the structure of glycans N-linked to proteins from various microalgae phyla and comment the consequences on the glycan engineering strategies that may be necessary to render those microalgae-made biopharmaceuticals compatible with human therapy.

Sorting cells of the microalga Chlorococcum littorale with increased triacylglycerol productivity

NARCIS (Netherlands)

Dominguez Teles, I.; Zwart, van der Mathijs; Kleinegris, D.M.M.; Wijffels, R.H.; Barbosa, M.J.

2016-01-01

Despite extensive research in the last decades, microalgae are still only economically feasible for high valued markets. Strain improvement is a strategy to increase productivities, hence reducing costs. In this work, we focus on microalgae selection: taking advantage of the natural biological

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)

Biogas Production From Cassava Starch Effluent Using Microalgae As Biostabilisator

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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.

Biological potential of microalgae in China for biorefinery-based production of biofuels and high value compounds.

Science.gov (United States)

Li, Jingjing; Liu, Ying; Cheng, Jay J; Mos, Michal; Daroch, Maurycy

2015-12-25

Microalgae abundance and diversity in China shows promise for identifying suitable strains for developing algal biorefinery. Numerous strains of microalgae have already been assessed as feedstocks for bioethanol and biodiesel production, but commercial scale algal biofuel production is yet to be demonstrated, most likely due to huge energy costs associated with algae cultivation, harvesting and processing. Biorefining, integrated processes for the conversion of biomass into a variety of products, can improve the prospects of microalgal biofuels by combining them with the production of high value co-products. Numerous microalgal strains in China have been identified as producers of various high value by-products with wide application in the medicine, food, and cosmetics industries. This paper reviews microalgae resources in China and their potential in producing liquid biofuels (bioethanol and biodiesel) and high value products in an integrated biorefinery approach. Implementation of a 'high value product first' principle should make the integrated process of fuels and chemicals production economically feasible and will ensure that public and private interest in the development of microalgal biotechnology is maintained. Copyright © 2015 Elsevier B.V. All rights reserved.

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 ...

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.

Enhanced Productivity of a Lutein-Enriched Novel Acidophile Microalga Grown on Urea

Directory of Open Access Journals (Sweden)

Carlos Vilchez

2010-12-01

Full Text Available Coccomyxa acidophila is an extremophile eukaryotic microalga isolated from the Tinto River mining area in Huelva, Spain. Coccomyxa acidophila accumulates relevant amounts of b-carotene and lutein, well-known carotenoids with many biotechnological applications, especially in food and health-related industries. The acidic culture medium (pH < 2.5 that prevents outdoor cultivation from non-desired microorganism growth is one of the main advantages of acidophile microalgae production. Conversely, acidophile microalgae growth rates are usually very low compared to common microalgae growth rates. In this work, we show that mixotrophic cultivation on urea efficiently enhances growth and productivity of an acidophile microalga up to typical values for common microalgae, therefore approaching acidophile algal production towards suitable conditions for feasible outdoor production. Algal productivity and potential for carotenoid accumulation were analyzed as a function of the nitrogen source supplied. Several nitrogen conditions were assayed: nitrogen starvation, nitrate and/or nitrite, ammonia and urea. Among them, urea clearly led to the best cell growth (~4 ´ 108 cells/mL at the end of log phase. Ammonium led to the maximum chlorophyll and carotenoid content per volume unit (220 mg·mL-1 and 35 mg·mL-1, respectively. Interestingly, no significant differences in growth rates were found in cultures grown on urea as C and N source, with respect to those cultures grown on nitrate and CO2 as nitrogen and carbon sources (control cultures. Lutein accumulated up to 3.55 mg·g-1 in the mixotrophic cultures grown on urea. In addition, algal growth in a shaded culture revealed the first evidence for an active xanthophylls cycle operative in acidophile microalgae.

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

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

Techno-economical evaluation of protein extraction for microalgae biorefinery

Science.gov (United States)

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

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 components, such as carbohydrates and protein, may lead to the sustainable and economical microalgae-based fuels. This paper discusses two relatively mild conditions for microalgal protein extraction, based on alkali and enzymes. Green microalgae (Chlorella fusca) with and without prior lipid removal were used as feedstocks. Under mild conditions, more protein could be extracted using proteases, with the highest yields for microalgae meal (without lipids). The data on protein extraction yields were used to calculate the costs for producing 1 ton of microalgal protein. The processing cost for the alkaline method was € 2448 /ton protein. Enzymatic method performed better from an economic point of view with € 1367 /ton protein on processing costs. However, this is still far from industrially feasible. For both extraction methods, biomass cost per ton of produced product were high. A higher protein extraction yield can partially solve this problem, lowering processing cost to €620 and 1180 /ton protein product, using alkali and enzyme, respectively. Although alkaline method has lower processing cost, optimization appears to be better achievable using enzymes. If the enzymatic method can be optimized by lowering the amount of alkali added, leading to processing cost of € 633/ton protein product. Higher revenue can be generated when the residue after protein extraction can be sold as fuel, or better as a highly digestible feed for cattle.

Microalgae Harvest through Fungal Pelletization—Co-Culture of Chlorella vulgaris and Aspergillus niger

Directory of Open Access Journals (Sweden)

Sarman Oktovianus Gultom

2014-07-01

Full Text Available Microalgae harvesting is a labor- and energy-intensive process and new approaches to harvesting microalgae need to be developed in order to decrease the costs. In this study; co-cultivatation of filamentous fungus (Aspergillus niger and microalgae (Chlorella vulgaris to form cell pellets was evaluated under different conditions, including organic carbon source (glucose; glycerol; and sodium acetate concentration; initial concentration of fungal spores and microalgal cells and light. Results showed that 2 g/L of glucose with a 1:300 ratio of fungi to microalgae provided the best culturing conditions for the process to reach >90% of cell harvest efficiency. The results also showed that an organic carbon source was required to sustain the growth of fungi and form the cell pellets. The microalgae/fungi co-cultures at mixotrophic conditions obtained much higher total biomass than pure cultures of each individual strains; indicating the symbiotic relationship between two strains. This can benefit the microbial biofuel production in terms of cell harvest and biomass production.

Paper-based device for separation and cultivation of single microalga.

Science.gov (United States)

Chen, Chih-Chung; Liu, Yi-Ju; Yao, Da-Jeng

2015-12-01

Single-cell separation is among the most useful techniques in biochemical research, diagnosis and various industrial applications. Microalgae species have great economic importance as industrial raw materials. Microalgae species collected from environment are typically a mixed and heterogeneous population of species that must be isolated and purified for examination and further application. Conventional methods, such as serial dilution and a streaking-plate method, are intensive of labor and inefficient. We developed a paper-based device for separation and cultivation of single microalga. The fabrication was simply conducted with a common laser printer and required only a few minutes without lithographic instruments and clean-room. The driving force of the paper device was simple capillarity without a complicated pump connection that is part of most devices for microfluidics. The open-structure design of the paper device makes it operable with a common laboratory micropipette for sample transfer and manipulation with a naked eye or adaptable to a robotic system with functionality of high-throughput retrieval and analysis. The efficiency of isolating a single cell from mixed microalgae species is seven times as great as with a conventional method involving serial dilution. The paper device can serve also as an incubator for microalgae growth on simply rinsing the paper with a growth medium. Many applications such as highly expressed cell selection and various single-cell analysis would be applicable. Copyright © 2015 Elsevier B.V. All rights reserved.

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

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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.

Simulation of temperature effect on microalgae culture in a tubular photo bioreactor for local solar irradiance

Science.gov (United States)

Shahriar, M.; Deb, Ujjwal Kumar; Rahman, Kazi Afzalur

2017-06-01

Microalgae based biofuel is now an emerging source of renewable energy alternative to the fossil fuel. This paper aims to present computational model of microalgae culture taking effect of solar irradiance and corresponding temperature in a photo bioreactor (PBR). As microalgae is a photosynthetic microorganism, so irradiance of sunlight is one of the important limiting factors for the proper growth of microalgae cells as temperature is associated with it. We consider the transient behaviour of temperature inside the photo bioreactor for a microalgae culture. The optimum range of temperature for outdoor cultivation of microalgae is about 16-35°c and out of this range the cell growth inhibits. Many correlations have already been established to investigate the heat transfer phenomena inside a tubular PBR. However, none of them are validated yet numerically by using a user defined function in a simulated model. A horizontal tubular PBR length 20.5m with radius 0.05m has taken account to investigate the temperature effect for the growth of microalgae cell. As the solar irradiance varies at any geographic latitude for a year so an empirical relation is established between local solar irradiance and temperature to simulate the effect. From our simulation, we observed that the growth of microalgae has a significant effect of temperature and the solar irradiance of our locality is suitable for the culture of microalgae.

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.

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.

Mild disintegration of the green microalgae Chlorella vulgaris using bead milling

NARCIS (Netherlands)

Postma, P.R.; Miron, T.L.; Olivieri, G.; Barbosa, M.J.; Wijffels, R.H.; Eppink, M.H.M.

2015-01-01

In this work, the mild disintegration of the microalgae Chlorella vulgaris for the release of intracellular products has been studied. By means of bead milling the microalgae suspensions were successfully disintegrated at different biomass concentrations (25–145 gDW kg-1) over a range of agitator

Lipid-based liquid biofuels from autotrophic microalgae: energetic and environmental performance

NARCIS (Netherlands)

Reijnders, L.

2013-01-01

Commercial cultivation of autotrophic microalgae for food production dates back to the 1950s. Autotrophic microalgae have also been proposed as a source for lipid-based liquid biofuels. As yet, there is no commercial production of such biofuels and estimated near-term prices are far in excess of

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.

Potential of Microalgae Cultivation in Dairy Wastewater as a Step in Low-Cost Biofuel Production

Directory of Open Access Journals (Sweden)

Basma Abbas Abdulmajeed

2018-04-01

Full Text Available The present study addresses adopting the organic and nutritious materials in dairy wastewater as media for cultivation of microalgae, which represent an important source of renewable energy. This study was carried out through cultivation of three types of microalgae; Chlorella sp., Synechococcus, and Anabaena. The results shows the success the cultivation of the Synechococcus and Chlorella Sp, while the Anabaena microalgae were in low-growth level. The highest growth was in the Synechococcus farm, followed by Chlorella and Anabaena. However, the growth of Synechococcus required 10 days to achieve this increase that represents a negative indicator of the adoption of this type of microalgae in this media to meet the desired aims. While Chlorella needs less than two days to start growing. Moreover, the data obtained from the experiment show that removal of chemical oxygen demand in Chlorella cultures was (72% more than that obtained from cultivation of other microalgae. Thus this microalgae is more efficient in wastewater treatment than other types.

Efficient harvesting of marine Chlorella vulgaris microalgae utilizing cationic starch nanoparticles by response surface methodology.

Science.gov (United States)

Bayat Tork, Mahya; Khalilzadeh, Rasoul; Kouchakzadeh, Hasan

2017-11-01

Harvesting involves nearly thirty percent of total production cost of microalgae that needs to be done efficiently. Utilizing inexpensive and highly available biopolymer-based flocculants can be a solution for reducing the harvest costs. Herein, flocculation process of Chlorella vulgaris microalgae using cationic starch nanoparticles (CSNPs) was evaluated and optimized through the response surface methodology (RSM). pH, microalgae and CSNPs concentrations were considered as the main independent variables. Under the optimum conditions of microalgae concentration 0.75gdry weight/L, CSNPs concentration 7.1mgdry weight/L and pH 11.8, the maximum flocculation efficiency (90%) achieved. Twenty percent increase in flocculation efficiency observed with the use of CSNPs instead of the non-particulate starch which can be due to the more electrostatic interactions between the cationic nanoparticles and the microalgae. Therefore, the synthesized CSNPs can be employed as a convenient and economical flocculants for efficient harvest of Chlorella vulgaris microalgae at large scale. Copyright © 2017 Elsevier Ltd. All rights reserved.

Marine microalgae used as food supplements and their implication in preventing cardiovascular diseases

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Mimouni Virginie

2015-07-01

Full Text Available Marine microalgae are photosynthetic microorganisms producing numerous bioactive molecules of interest for health and disease care such as lipids rich in omega-3 fatty acids -as eicosapentaenoic acid (EPA, 20:5 n-3 and docosahexaenoic acid (DHA, 22:6 n-3- and carotenoids (e.g., β-carotene, fucoxanthin, astaxanthin. It has already been shown that these molecules, individually used, are benefic in the prevention of diseases such as those associated with the cardiovascular risks, but also in some carcinomas. When these molecules are combined, synergistic effects may be observed. Microalgae, as a dietary supplement, can be used to study these synergistic effects in animal models in which dyslipidemia can be induced by a nutrition treatment. Different marine microalgae of interest are studied in this context to determine their potential effect as an alternative source to marine omega-3 rich fish oils, actually widely used for human health. Actually, the pharmaceutical and nutrition industries are developing health research programs involving microalgae, trying to limit the dramatic reduction of fish stocks and the associated pollution in the marine environment. The aim of this review is threefold: (1 to present research on lipids, particularly long chain polyunsaturated fatty acids, as components of marine microalgae used as food supplements; (2 to present the health benefits of some microalgae or their extracts, in particular in the prevention of cardiovascular diseases and (3 to highlight the role of Odontella aurita, a marine microalga rich in EPA used as food supplement with the aim of preventing cardiovascular diseases.

Use of Solid Waste from Thermoelectric Plants for the Cultivation of Microalgae

Directory of Open Access Journals (Sweden)

Bruna da Silva Vaz

2016-01-01

Full Text Available ABSTRACT The aim of this study was to analyze the influence of solid waste on the cultivation of the microalgae Spirulina sp. LEB 18 and Chlorella fusca LEB 111 with 0, 40, 80 and 120 ppm of mineral coal ash. The addition of the ash did not inhibit the cultivation of microalgae at the tested concentrations, showing that it could be used for the cultivation of these microalgae due to the minerals present in the ash, which might substitute the nutrients needed for their growth.

Removal of metal from acid mine drainage using a hybrid system including a pipes inserted microalgae reactor.

Science.gov (United States)

Park, Young-Tae; Lee, Hongkyun; Yun, Hyun-Shik; Song, Kyung-Guen; Yeom, Sung-Ho; Choi, Jaeyoung

2013-12-01

In this study, the microalgae culture system to combined active treatment system and pipe inserted microalgae reactor (PIMR) was investigated. After pretreated AMD in active treatment system, the effluent load to PIMR in order to Nephroselmis sp. KGE 8 culture. In experiment, effect of iron on growth and lipid accumulation in microalgae were inspected. The 2nd pretreatment effluent was economic feasibility of microalgae culture and lipid accumulation. The growth kinetics of the microalgae are modeled using logistic growth model and the model is primarily parameterized from data obtained through an experimental study where PIMR were dosed with BBM, BBM added 10 mg L(-1) iron and 2nd pretreatment effluent. Moreover, the continuous of microalgae culture in PIMR can be available. Overall, this study indicated that the use of pretreated AMD is a viable method for culture microalgae and lipid accumulation. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

Volatile Metabolites Emission by In Vivo Microalgae-An Overlooked Opportunity?

Science.gov (United States)

Achyuthan, Komandoor E; Harper, Jason C; Manginell, Ronald P; Moorman, Matthew W

2017-07-31

Fragrances and malodors are ubiquitous in the environment, arising from natural and artificial processes, by the generation of volatile organic compounds (VOCs). Although VOCs constitute only a fraction of the metabolites produced by an organism, the detection of VOCs has a broad range of civilian, industrial, military, medical, and national security applications. The VOC metabolic profile of an organism has been referred to as its 'volatilome' (or 'volatome') and the study of volatilome/volatome is characterized as 'volatilomics', a relatively new category in the 'omics' arena. There is considerable literature on VOCs extracted destructively from microalgae for applications such as food, natural products chemistry, and biofuels. VOC emissions from living (in vivo) microalgae too are being increasingly appreciated as potential real-time indicators of the organism's state of health (SoH) along with their contributions to the environment and ecology. This review summarizes VOC emissions from in vivo microalgae; tools and techniques for the collection, storage, transport, detection, and pattern analysis of VOC emissions; linking certain VOCs to biosynthetic/metabolic pathways; and the role of VOCs in microalgae growth, infochemical activities, predator-prey interactions, and general SoH.

Techno-economic analysis of solar integrated hydrothermal liquefaction of microalgae

International Nuclear Information System (INIS)

Pearce, Matthew; Shemfe, Mobolaji; Sansom, Christopher

2016-01-01

Highlights: • Hydrothermal liquefaction and concentrated solar power provide integrated biofuel technology. • Heat kinetics and energy efficiency Aspen plus modelling of CSP and HTL. • Microalgae biofuel minimum fuel sales price of $1.23/kg. - Abstract: Integration of Hydrothermal Liquefaction (HTL) of microalgae biomass with concentrated solar power thermal processing (CSP) for bio-oil production is a potential processing pathway for energy efficient generation of renewable biofuels. Solar HTL infrastructure avoids additional bolt-on components of conventional solar parabolic trough systems used for electricity production including heat transfer fluids, counter current heat exchangers, fluid transfer interconnectivity and electrical power control systems. The absence of such capital intensive additional equipment considerably reduces the production costs of solar HTL biofuels compared to electricity generation from conventional CSP power systems. An economic and market appraisal of variance and system economic resilience is presented. It is hypothesised that the combination of nutrient recycling with HTL/CSP unification has the potential for economically sustainable microalgae bio-oil production. A microalgae biofuel minimum fuel sales price of $1.23/kg has been modelled. Further experimental work would be able to validate this integrated model.

A Label-Free Microfluidic Biosensor for Activity Detection of Single Microalgae Cells Based on Chlorophyll Fluorescence

Directory of Open Access Journals (Sweden)

Junsheng Wang

2013-11-01

Full Text Available Detection of living microalgae cells is very important for ballast water treatment and analysis. Chlorophyll fluorescence is an indicator of photosynthetic activity and hence the living status of plant cells. In this paper, we developed a novel microfluidic biosensor system that can quickly and accurately detect the viability of single microalgae cells based on chlorophyll fluorescence. The system is composed of a laser diode as an excitation light source, a photodiode detector, a signal analysis circuit, and a microfluidic chip as a microalgae cell transportation platform. To demonstrate the utility of this system, six different living and dead algae samples (Karenia mikimotoi Hansen, Chlorella vulgaris, Nitzschia closterium, Platymonas subcordiformis, Pyramidomonas delicatula and Dunaliella salina were tested. The developed biosensor can distinguish clearly between the living microalgae cells and the dead microalgae cells. The smallest microalgae cells that can be detected by using this biosensor are 3 μm ones. Even smaller microalgae cells could be detected by increasing the excitation light power. The developed microfluidic biosensor has great potential for in situ ballast water analysis.

A Label-Free Microfluidic Biosensor for Activity Detection of Single Microalgae Cells Based on Chlorophyll Fluorescence

Science.gov (United States)

Wang, Junsheng; Sun, Jinyang; Song, Yongxin; Xu, Yongyi; Pan, Xinxiang; Sun, Yeqing; Li, Dongqing

2013-01-01

Detection of living microalgae cells is very important for ballast water treatment and analysis. Chlorophyll fluorescence is an indicator of photosynthetic activity and hence the living status of plant cells. In this paper, we developed a novel microfluidic biosensor system that can quickly and accurately detect the viability of single microalgae cells based on chlorophyll fluorescence. The system is composed of a laser diode as an excitation light source, a photodiode detector, a signal analysis circuit, and a microfluidic chip as a microalgae cell transportation platform. To demonstrate the utility of this system, six different living and dead algae samples (Karenia mikimotoi Hansen, Chlorella vulgaris, Nitzschia closterium, Platymonas subcordiformis, Pyramidomonas delicatula and Dunaliella salina) were tested. The developed biosensor can distinguish clearly between the living microalgae cells and the dead microalgae cells. The smallest microalgae cells that can be detected by using this biosensor are 3 μm ones. Even smaller microalgae cells could be detected by increasing the excitation light power. The developed microfluidic biosensor has great potential for in situ ballast water analysis. PMID:24287532

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...

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.

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.

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.

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.

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.

From transient response of a compact photobioreactor for microalgae cultivation

Energy Technology Data Exchange (ETDEWEB)

Dilay, Emerson; Ribeiro, Robert Luis Lara; Pulliam, Raevon; Mariano, Andre Bellin [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Nucleo de Pesquisa e Desenvolvimento em Energia Auto-Sustentavel; Ordonez, Juan Carlos [Florida State University, Tallahassee, FL (United States). Dept. of Mechanical Engineering and Center for Advanced Power Systems], E-mail: ordonez@caps.fsu.edu; Vargas, Jose Viriato Coelho [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Engenharia Mecanica

2010-07-01

Biofuels from microalgae are currently the subject of funded scientific research in many countries due to their high productivity of oil when compared with other crops. Microalgae can also be used in many important applications such as to obtain compounds of interest for food, chemicals, and pharmaceuticals. The high productivity of microalgae when compared with other crops is achieved because agricultural land is not mandatory for their cultivation, since they can be grown in open ponds, sea or vertical photo bioreactors. In this paper, a mathematical model is introduced for assessing the transient microalgae growth as a function of variable light intensity, temperature and environmental conditions in the daily cycle. Photo bioreactor geometry is considered as well. Light intensity is obtained from sun position, photo bioreactor geometry, and the installation location in the world. The photo bioreactor was discretized in space by the the volume element method. Balances of energy and species together with thermodynamics, heat transfer and chemistry empirical and theoretical correlations are applied to each volume element. Therefore, a system of ordinary differential equations with respect to time only is capable of delivering temperatures and concentrations as functions of space and time, even with a coarse mesh. The numerical results are capable of predicting the transient and steady state photo bioreactor biomass production with low computational time. Microalgae specific growth rate as a function of average light intensity inside the tubes and time was calculated. As a result, the model is expected to be a useful tool for simulation, design, and optimization of compact photo bioreactors. (author)

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

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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.

Pilot scale harvesting, separation and drying of microalgae biomass from compact photo-bioreactor

Energy Technology Data Exchange (ETDEWEB)

Cardoso, Alberto Tadeu Martins; Luz Junior, Luiz Fernando de Lima [Dept. de Engenharia Quimica. Universidade Federal do Parana, Curitiba, PR (Brazil)], e-mail: luzjr@ufpr.br; Mariano, Andre Bellin; Ghidini, Luiz Francisco Correa; Gnoatto, Victor Eduardo; Locatelli Junior, Vilson; Mello, Thiago Carvalho de; Vargas, Jose Viriato Coelho [Nucleo de Pesquisa e Desenvolvimento em Energia Autossustentavel (NPDEAS). Dept. de Engenharia Mecanica. Universidade Federal do Parana, Curitiba (Brazil)], E-mail: jvargas@demec.ufpr.br

2010-07-01

Bio diesel produced from microalgae lipids is gaining a substantial ground in the search for renewable energy sources. In order to optimize the operating conditions of a continuous process, several experiments were realized, both in laboratory and pilot scale. The microalgae cultivation can be conducted in a photo-bioreactor, a closed system which allows parameters control and necessarily involves the aquatic environment. Because of that, the use of separation unit operations is required. The process starts in a proposed compact photo-bioreactor, which consist of a chain of transparent tubes with 6 cm of diameter arranged in parallel where the cultivation media circulate with the help of a pump. This arrangement offers a closed culture with less risk of contamination and maintains a minimum contact with the environment. The microalgae grow inside the pipes under incidence of ambient light. In this paper, harvesting, separation and drying were studied, as part of the processes of a sustainable energy plant under construction at UFPR, as shown in Fig. 1. To control the production in a photo-bioreactor in continuous system, it is necessary to monitor the concentration of microalgae growth in suspension. To measure the cell concentration in this equipment, an optic sensor has been developed. The microalgae biomass separation from the culture media is achieved by microalgae flocculation. Several cultivation situations have been tested with different NaOH concentrations, increasing the pH to 10. The system was kept under agitation during the addition by an air pump into the tank. Thereafter the system was maintained static. After a short time, it was observed that the microalgae coagulated and settled. The clarified part water was removed, remaining a concentrated microalgae suspension. Our results suggest that pH increase is a suitable methodology for microalgae separation from the growth suspension. The microalgae sedimentation time was recorded, which allowed the

Uso de Microalgas para Produção de Biodiesel

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Gillianne Assis Carneiro

2018-01-01

Full Text Available A maioria das demandas energéticas da sociedade ainda são atendidas pelos combustíveis de origem fóssil. Porém, essa fonte vem sendo substituída por outras renováveis, menos agressivas ao meio ambiente e com melhor custo/benefício. Como exemplo, podemos mencionar os biocombustíveis produzidos a partir de plantas oleaginosas e microrganismos, que são capazes de substituir os derivados do petróleo com eficiência equivalente. Graças a sua elevada produção de lipídios, as microalgas, cujo diâmetro não ultrapassa 2 mm, são objeto de estudos e estão sendo aplicadas na produção de biocombustíveis, em especial, do biodiesel, sendo que, cerca de 150 espécies de microalgas são usadas comercialmente. O objetivo deste trabalho foi realizar uma revisão de literatura sobre a produção de biodiesel a partir de microalgas. Este estudo é do tipo teórico-conceitual, visto que foi elaborado a partir da realização de pesquisas na literatura nacional e internacional sobre a produção de biocombustíveis a partir de microalgas, além da consulta a órgãos governamentais e legislações pertinentes.  Ademais, pretende-se apresentar as principais técnicas de cultivo e de produção, bem como as principais vantagens e desvantagens da utilização das microalgas para produção de biodiesel. A partir da problemática ambiental e da redução das reservas fósseis faz-se necessário o investimento em fontes alternativas, sendo o biodiesel produzido a partir de microalgas uma opção a ser considerada e aperfeiçoada para produção e utilização em escala comercial.

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

Biodiesel Production from Microalgae by Extraction – Transesterification Method

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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

Resistance of common carp (Cyprinus carpio L.) to oxidative stress after chloramine-T treatment is increased by microalgae carotenoid-rich diet.

Science.gov (United States)

Stara, Alzbeta; Sergejevova, Magda; Kozak, Pavel; Masojidek, Jiri; Velisek, Josef; Kouba, Antonin

2014-01-01

In fish aquaculture, disinfectants are used against bacterial and protozoal infections. These compounds cause oxidative stress that may stimulate the generation of reactive oxygen species, and subsequently the alteration in antioxidant systems of exposed organisms. Antioxidants like carotenoids present in microalgae increase carp resistance to oxidative stress after chemical treatment. The aim of these experiments was to prove increased resistance of common carp (Cyprinus carpio L.) juveniles fed on experimental diets with microalgae biomass supplement (Algadiets) to oxidative stress caused by a disinfectant chloramine-T. In indoor experiments fish were fed on laboratory-prepared extruded diets containing supplement of Chlorella spp. (cf. C. vulgaris Beijerinck) biomass which contains antioxidants (carotenoids) like lutein. The young-of-the-year-old fish were acclimatized and fed on basal diet (control group) and the on diets containing 1, 2, 5 and 10% (w/w) of spray-dried Chlorella biomass (Algadiet 1, 2, 5 and 10) for 14 days followed by 6 weeks. Consequently, fish were treated daily with chloramine-T (Chl-T) at concentration of 10 mg x l(-1) for 1 h in three consecutive days. After this treatment, the indices of oxidative stress and antioxidant enzyme activity were assayed in fish gill, muscle and hepatopancreas. The fish fed on different Algadiets had increased antioxidant enzyme activities of glutathione peroxidase, glutathione reductase and catalase in flesh after the exposure to Chl-T. Higher activities of superoxide dismutase, glutathione peroxidase and glutathione reductase were also observed in the hepatopancreas in all tested concentrations compared to the control group fed on the basal diet. The increased production and activity of antioxidant enzymes confirmed improved protection ability of fish tissues against oxidative damage when microalgae biomass was supplemented to the fish diet which was more pronounced by higher microalgae supplement in

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

Culture of microalgae biomass for valorization of table olive processing water

International Nuclear Information System (INIS)

Contreras, C.G.; Serrano, A.; Ruiz-Filippi, G.; Borja, R.; Fermoso, F.G.

2016-01-01

Table olive processing water (TOPW) contains many complex substances, such as phenols, which could be valorized as a substrate for microalgae biomass culture. The aim of this study was to assess the capability of Nannochloropsis gaditana to grow in TOPW at different concentrations (10- 80%) in order to valorize this processing water. Within this range, the highest increment of biomass was determined at percentage of 40% of TOPW, reaching an increment of 0.36 ± 0.05 mg volatile suspended solids (VSS)/L. Components of algal biomass were similar for the experiments at 10-40% of TOPW, where proteins were the major compounds (56-74%). Total phenols were retained in the microalgae biomass (0.020 ± 0.002 g of total phenols/g VSS). Experiments for 80% of TOPW resulted in a low production of microalgae biomass. High organic matter, nitrogen, phosphorus and phenol removal were achieved in all TOPW concentrations. Although high-value products, such as proteins, were obtained and high removal efficiencies of nutrients were determined, microalgae biomass culture should be enhanced to become a suitable integral processing water treatment. [es

Potency of Microalgae as Biodiesel Source in Indonesia

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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.

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.

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.

Assessment of Methods to Pretreat Microalgal Biomass for Enhanced Biogas Production

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Aline de L. Marques

2018-06-01

Full Text Available In anaerobic digestion of microalgae, the intracellular material may remain intact due to the non-ruptured membrane and/or cell wall, reducing the methane yield. Therefore, different pretreatment methods were evaluated for the solubilization of microalgae Scenedesmus sp. The anaerobic digestion of biomass hydrolyzed at 150 °C for 60 min with sulfuric acid 0.1% v/v showed higher methane yield (204-316 mL methane/g volatile solids applied compared to raw biomass (104-163 mL methane/g volatile solids applied. The replacement of sulfuric acid with carbonic acid (by bubbling carbon dioxide up to pH 2.0 provided results similar to those obtained with sulfuric acid, reaching solubilization of 41.6% of the biomass. This result shows that part of the flue gas (containing carbon dioxide and other acid gases as well as high temperatures may be used for the hydrolysis of the residual biomass from microalgae, thus lowering operational costs (e.g., energy consumption and chemical input.

Experimental and theoretical study of microalgal competition in laboratory and natural ecosystems

Science.gov (United States)

Pisman, T. I.; Somova, L. A.

An important aspect of studying mixed cultures of microalgae is the artificial ecosystems containing algal culture as a regeneration link and a source of vegetable substances. The peculiarities of studying the stability of microalgae mixed cultures in the laboratory and natural environment have been considered in the work. The role of factors most essentially affecting the species structure of phytoplankton community (temperature factor, light intensity, pH environments, elements of mineral nutrition, algal metabolites, predation and fluctuation of environmental conditions) has been displayed. As a result of experimental and theoretical modelling of the microalgae Chlorella vulgaris and Scenedesmus quadricauda competition under limitation on nitrogen, the impossibility of their co-existence has been revealed. Under these conditions Chl. vulgaris turned out to be less competitive than Sc. quadricauda. The influence of the ratio of biogenic elements concentration in the environment, which should be recognized as an independent regulatory factor limiting growth of populations in the community and, thus affecting its structure, has been analyzed.

Bio-gasification of post transesterified microalgae residues: A route to improving overall process renewabilities

DEFF Research Database (Denmark)

Ehimen, Ehiazesebhor Augustine

Using results from experiments and process modelling tools, a renewability assessment was carried out for the use of the conventional and in-situ transesterification processes for a large scale microalgae biodiesel production. In a present day scenario, all the transesterification processes were...... shown to be non-renewable. The process renewability of biodiesel production from microalgae was found to significantly improve with the use of renewable electricity, reacting alcohols from biomass fermentation and process heating and biomass drying using heat from wood pellet combustion or heat pump...... technology. The anaerobic digestion of the microalgae residues to generate methane from was further seen to lead to positive renewabilities for the considered microalgae-biodiesel processes....

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

Pyrolysis characteristics and kinetics of microalgae via thermogravimetric analysis (TGA): A state-of-the-art review.

Science.gov (United States)

Bach, Quang-Vu; Chen, Wei-Hsin

2017-12-01

Pyrolysis is a promising route for biofuels production from microalgae at moderate temperatures (400-600°C) in an inert atmosphere. Depending on the operating conditions, pyrolysis can produce biochar and/or bio-oil. In practice, knowledge for thermal decomposition characteristics and kinetics of microalgae during pyrolysis is essential for pyrolyzer design and pyrolysis optimization. Recently, the pyrolysis kinetics of microalgae has become a crucial topic and received increasing interest from researchers. Thermogravimetric analysis (TGA) has been employed as a proven technique for studying microalgae pyrolysis in a kinetic control regime. In addition, a number of kinetic models have been applied to process the TGA data for kinetic evaluation and parameters estimation. This paper aims to provide a state-of-the art review on recent research activities in pyrolysis characteristics and kinetics of various microalgae. Common kinetic models predicting the thermal degradation of microalgae are examined and their pros and cons are illustrated. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

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.

Growth of locally isolated microalga in POME to produce lipid as alternative energy sources

Science.gov (United States)

Elvitriana; Munir, E.; Delvian; Wahyuningsih, H.

2018-04-01

Purpose of this study was to find the best growth of locally isolated microalgae that produce lipids from Palm Oil Mill Effluent (POME) as an alternative energy source. Microalgae was cultivated in POME in glass vessel at room temperature using a lighting intensity of 13,000 lux and continuously aeration for 24 and 12 hours, respectively. Biomass of microalgae were analyzed daily to get their growth by spectrophotometry at 624 nm wavelength, whereas Modified Bligh and Dyer method determined lipid content. Results show that the best growth occurred at 10% inoculum with lighting cycle and aeration of 24 hours (on/off) and resulting highest biomass content of 0.99 g dry weight/L followed by the decrease of organic substances in POME. The percentage reduction of COD, BOD, TSS, and oil at POME reached above 92%, while phosphate concentration reached 89.2%. Cultivation of microalgae in POME for 12 days showed its ability to reduce organic substances and nutrients in POME and produced biomass with lipid content of 35%. These results reached to the conclusion that locally isolated microalgae has an ability to treat POME safely for environment and POME can be used as a growing medium of microalgae that produces lipids.

Culture of microalgae biomass for valorization of table olive processing water

Directory of Open Access Journals (Sweden)

Contreras, C. G.

2016-09-01

Full Text Available Table olive processing water (TOPW contains many complex substances, such as phenols, which could be valorized as a substrate for microalgae biomass culture. The aim of this study was to assess the capability of Nannochloropsis gaditana to grow in TOPW at different concentrations (10- 80% in order to valorize this processing water. Within this range, the highest increment of biomass was determined at percentage of 40% of TOPW, reaching an increment of 0.36 ± 0.05 mg volatile suspended solids (VSS/L. Components of algal biomass were similar for the experiments at 10-40% of TOPW, where proteins were the major compounds (56-74%. Total phenols were retained in the microalgae biomass (0.020 ± 0.002 g of total phenols/g VSS. Experiments for 80% of TOPW resulted in a low production of microalgae biomass. High organic matter, nitrogen, phosphorus and phenol removal were achieved in all TOPW concentrations. Although high-value products, such as proteins, were obtained and high removal efficiencies of nutrients were determined, microalgae biomass culture should be enhanced to become a suitable integral processing water treatment.El agua resultante del proceso de elaboración de la aceituna de mesa (TOPW presenta un elevado contenido en sustancias complejas, como fenoles, que podría permitir su uso como sustrato para el cultivo de microalgas. El objetivo de este estudio se centra en evaluar la capacidad de crecimiento de Nannochloropsis gaditana en TOPW a distintas concentraciones (10-80% con vistas a la valorización de estas aguas. El mayor incremento de biomasa se obtuvo para un porcentaje del 40% de TOPW, alcanzando un aumento de 0.36 ± 0.50 mg sólidos en suspensión volátiles (SSV/L. Los componentes presentes en la biomasa han sido similares para los experimentos con 10-40% de TOPW, siendo las proteínas los compuestos mayoritarios en todos los casos (56-74%. Los fenoles totales quedaron retenidos en las microalgas, alcanzando una concentraci

Heavy metals removals from wet market wastewater by phycoremediation technology

Science.gov (United States)

Jais, N. M.; Mohamed, R. M. S. R.; Apandi, N.; Al-Gheethi, A. A.

2018-04-01

The wet market provided fresh foodstuff. Unfortunately, the sullage commonly discharged directly to the drainage without any treatment. Hence, this research was focused on culturing the Scenedesmus sp. and implemented the phycoremediation process to wet market wastewater and to measure the heavy metal removals by Scenedesmus sp. There are two different time collected samples: (1) Sample at 7 a.m. and (2) Sample at 9 a.m.. The five samples were collected for each time sampling from of the Parit Raja Public Market, Batu Pahat wastewater (with additional of five different concentrations of Scenedesmus sp. which are 1.235x106, 1.224x106, 1.220x106, 1.213x106 and 1.203x106 cell/ml). This experiment was conducted within eight days for culturing Scenedesmus sp. and phycoremediation within another eight days. The analysis was done with changes of DO and pH and heavy metals removal during phycoremediation. Based on the result, the optimum efficiency removals for each heavy metal had achieved (36.62-100%) and the optimum concentration for Sample 7 a.m. and Sample 9 a.m. is Concentration 1 (1.235x106 cell/ml) obtained 81.18-100% of heavy metal removals. Concentration of microalgae is statistically correlated well with Fe (p0.05) in influencing high nutrient removal in the wastewater.

Mathematical modeling and experimental validation of Phaeodactylum tricornutum microalgae growth rate with glycerol addition

Energy Technology Data Exchange (ETDEWEB)

Morais, Keli Cristiane Correia; Ribeiro, Robert Luis Lara; Santos, Kassiana Ribeiro dos; Mariano, Andre Bellin [Mariano Center for Research and Development of Sustainable Energy (NPDEAS), Curitiba, PR (Brazil); Vargas, Jose Viriato Coelho [Departament of Mechanical Engineering, Federal University of Parana (UFPR) Curitiba, PR (Brazil)

2010-07-01

The Brazilian National Program for Bio fuel Production has been encouraging diversification of feedstock for biofuel production. One of the most promising alternatives is the use of microalgae biomass for biofuel production. The cultivation of microalgae is conducted in aquatic systems, therefore microalgae oil production does not compete with agricultural land. Microalgae have greater photosynthetic efficiency than higher plants and are efficient fixing CO{sub 2}. The challenge is to reduce production costs, which can be minimized by increasing productivity and oil biomass. Aiming to increase the production of microalgae biomass, mixotrophic cultivation, with the addition of glycerol has been shown to be very promising. During the production of biodiesel from microalgae there is availability of glycerol as a side product of the transesterification reaction, which could be used as organic carbon source for microalgae mixotrophic growth, resulting in increased biomass productivity. In this paper, to study the effect of glycerol in experimental conditions, the batch culture of the diatom Phaeodactylum tricornutum was performed in a 2-liter flask in a temperature and light intensity controlled room. During 16 days of cultivation, the number of cells per ml was counted periodically in a Neubauer chamber. The calculation of dry biomass in the control experiment (without glycerol) was performed every two days by vacuum filtration. In the dry biomass mixotrophic experiment with glycerol concentration of 1.5 M, the number of cells was assessed similarly in the 10{sup th} and 14{sup th} days of cultivation. Through a volume element methodology, a mathematical model was written to calculate the microalgae growth rate. It was used an equation that describes the influence of irradiation and concentration of nutrients in the growth of microalgae. A simulation time of 16 days was used in the computations, with initial concentration of 0.1 g l{sup -1}. In order to compare

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.

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

Science.gov (United States)

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

2015-06-15

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

Setting the conditions for phycoremediation of radionuclide microalgae Dunaliella salina and Chlorella vulgaris

International Nuclear Information System (INIS)

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

2016-01-01

This presentation deals with bioremediation using microalgae - by phycoremediation. Microalgae are economically low profile compared to the plants, their cultivation can be carried out in laboratory conditions. They can survive in extreme conditions, they occur in all habitats and have faster growth. Halophilous green D. salina can accumulate heavy metals such as Zn, Cu and Cd. It occurs in hypersaline environment with tolerance (0.2 to 35) % NaCl. It contains high amounts of carotenoids, which protect it against formation of free radicals from UV radiation. Chlorella vulgaris is a representative of eukaryotic green microalgae with the highest chlorophyll content with the appearance in fresh water. Its phycoremediant ability are found in N and P elements, which are used as its nutritional components as well as for Cu, Cr, Cd, Pb, Au. The experiments were carried out using a peristaltic pump ISMATEC Model: ISM851 (flow rate 2 cm"3 min"-"1) followed by monitoring of time dependence of decrease of activity of the microalgae solutions. For evaluation of the samples was used HPGe gamma spectrometer (measurement time of the samples: 600 sec) from ORTEC Company and measured spectra were evaluated with software GammaVision from ORTEC. The measured results showed that the most effective phycoremediation of microalgae Dunaliella salina toke place in an environment of pH 3, and even more at pH 8. The fact that the D. salina is able of phycoremediation at so acidic pH can contribute to its applications in extreme conditions or in the coastal areas in view of that it is halophilic. At freshwater microalgae Chlorella vulgaris was found the best phytoremediation potential in its natural environment at pH of 6. Because this microalgae is freshwater, it may find application in inland or in liquid radioactive waste from nuclear facilities.(authors)

Lipidomic Approaches towards Deciphering Glycolipids from Microalgae as a Reservoir of Bioactive Lipids

Directory of Open Access Journals (Sweden)

Elisabete da Costa

2016-05-01

Full Text Available In recent years, noteworthy research has been performed around lipids from microalgae. Among lipids, glycolipids (GLs are quite abundant in microalgae and are considered an important source of fatty acids (FAs. GLs are rich in 16- and 18-carbon saturated and unsaturated fatty acids and often contain polyunsaturated fatty acids (PUFAs like n-3 α-linolenic (ALA 18:3, eicosapentaenoic (EPA, 20:5 and docosahexaenoic (DHA, 22:6. GLs comprise three major classes: monogalactosyldiacyl glycerolipids (MGDGs, digalactosyl diacylglycerolipids (DGDGs and sulfoquinovosyl diacylglycerolipids (SQDGs, whose composition in FA directly depends on the growth conditions. Some of these lipids are high value-added compounds with antitumoral, antimicrobial and anti-inflammatory activities and also with important nutritional significance. To fully explore GLs’ bioactive properties it is necessary to fully characterize their structure and to understand the relation between the structure and their biological properties, which can be addressed using modern mass spectrometry (MS-based lipidomic approaches. This review will focus on the up-to-date FA composition of GLs identified by MS-based lipidomics and their potential as phytochemicals.

Pyrolysis mechanism of microalgae Nannochloropsis sp. based on model compounds and their interaction

International Nuclear Information System (INIS)

Wang, Xin; Tang, Xiaohan; Yang, Xiaoyi

2017-01-01

Highlights: • Pyrolysis experiments were conducted by model compounds of algal components. • Interaction affected little bio-crude yield of model compounds co-pyrolysis. • Some interaction pathways between microalgae components were recommended. • N-heterocyclic compounds were further pyrolysis products of Maillard reaction products. • Surfactant synthesis (lipid-amino acids and lipid-glucose) between algal components. - Abstract: Pyrolysis is one of important pathways to convert microalgae to liquid biofuels and key components of microalgae have different chemical composition and structure, which provides a barrier for large-scale microalgae-based liquid biofuel application. Microalgae component pyrolysis mechanism should be researched to optimal pyrolysis process parameters. In this study, single pyrolysis and co-pyrolysis of microalgal components (model compounds castor oil, soybean protein and glucose) were conducted to reveal interaction between them by thermogrametric analysis and bio-crude evaluation. Castor oil (model compound of lipid) has higher pyrolysis temperature than other model compounds and has the maximum contribution to bio-crude formation. Bio-crude from soybean protein has higher N-heterocyclic compounds as well as phenols, which could be important aromatic hydrocarbon source during biorefineries and alternative aviation biofuel production. Potential interaction pathways based on model compounds are recommended including further decomposition of Maillard reaction products (MRPs) and surfactant synthesis, which indicate that glucose played an important role on pyrolysis of microalgal protein and lipid components. The results should provide necessary information for microalgae pyrolysis process optimization and large-scale pyrolysis reactor design.

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

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Adoracion Arañez

1992-06-01

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

Active compounds from cyanobacteria and microalgae: properties and potential applications in biomedicine

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Alexey Llopiz

2016-05-01

Full Text Available Cyanobacteria and microalgae are source of many chemicals substances with potential applications on biopharmaceutical industry. Many structures have been characterized in these organism, such as: peptides, proteins, carbohydrates, terpenoids, polyinsatured fatty acids, flavonoids, phenolic compounds, vitamins, porfirins and other organic substances. Chemicals structures of isolated compounds are diverse and it depends of microalgae habitats. Pharmacological activities located in microalgae are bactericides, immunomodulatory, antioxidants, cytoprotective, fungicides and antivirals. These properties may possible the potential treatment of many diseases including autoimmunes disorders, tumoral, and infectious process. In this review are presented and discussed some elements associated to chemical structure and biological activities around of compounds with potential uses as biopharmaceuticals.

The effect of growth phase on the surface properties of three oleaginous microalgae (Botryococcus sp. FACGB-762, Chlorella sp. XJ-445 and Desmodesmus bijugatus XJ-231).

Science.gov (United States)

Xia, Ling; Huang, Rong; Li, Yinta; Song, Shaoxian

2017-01-01

The effects of growth phase on the lipid content and surface properties of oleaginous microalgae Botryococcus sp. FACGB-762, Chlorella sp. XJ-445 and Desmodesmus bijugatus XJ-231 were investigated in this study. The results showed that throughout the growth phases, the lipid content of microalgae increased. The surface properties like particle size, the degree of hydrophobicity, and the total concentration of functional groups increased while net surface zeta potential decreased. The results suggested that the growth stage had significant influence not only on the lipid content but also on the surface characteristics. Moreover, the lipid content was significantly positively related to the concentration of hydroxyl functional groups in spite of algal strains or growth phases. These results provided a basis for further studies on the refinery process using oleaginous microalgae for biofuel production.

Techno-economic assessment of micro-algae as feedstock for renewable bio-energy production

NARCIS (Netherlands)

Jonker, J.G.G.; Faaij, A.P.C.|info:eu-repo/dai/nl/10685903X

2013-01-01

This paper determines the energy consumption ratio and overall bio-energy production costs of microalgae cultivation, harvesting and conversion to secondary energy carriers, thus helping to clarify future perspectives of micro-algae production for energy purposes. A limitation growth model is

Potency of Microalgae as Biodiesel Source in Indonesia

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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.

Cultivation of microalgae Spirulina platensis (Arthrospira platensis from biological treatment of swine wastewater Cultivo da microalga Spirulina platensis (Arthrospira platensis a partir de tratamento biológico de efluente suíno

Directory of Open Access Journals (Sweden)

Natália Mezzomo

2010-03-01

Full Text Available The microalgae biomass production from swine wastewater is a possible solution for the environmental impact generated by wastewater discharge into water sources. The biomass can be added to fish feed, which can be used in the formulation of meat products. This work addresses the adaptation of the microalgae Spirulina platensis (Arthrospira platensis in swine wastewater and the study of the best dilution of the wastewater for maximum biomass production and for removal of Chemical Oxygen Demand (COD, ammonia and phosphorous to the microalgae. The cultivation of Spirulina platensis, strain Paracas presented maximum cellular concentrations and maximum specific growth rates in the wastewater concentration of 5.0 and 8.5%. The highest COD removals occurred with 26.5 and 30.0% of wastewater in the medium. The maximum removal of total phosphorous (41.6%, was with 8.5% of wastewater, which is related to the microalgae growth. The results of Spirulina culture in the swine wastewater demonstrated the possibility of using these microalgae for the COD and phosphorous removal and for biomass production.A produção de biomassa de microalgas a partir de efluente suíno consiste em uma possível solução para o impacto ambiental gerado pela descarga de efluentes em fontes naturais. A biomassa produzida pode ser adicionada a rações de peixes, os quais podem ser utilizados na formulação de produtos cárneos. O objetivo deste trabalho foi a adaptação da microalga Spirulina platensis (Arthrospira platensis em efluente suíno e o estudo da diluição ideal de efluente para obter a máxima produção de biomassa e remoção de Demanda Química de Oxigênio (DQO, amônia e fósforo do efluente pela microalga. O cultivo da Spirulina platensis, cepa Paracas apresentou máxima concentração celular e máxima taxa específica de crescimento em concentrações de efluente de 5,0 e 8,5%. As maiores remoções de DQO ocorreram com 26,5 e 30,0% de efluente no meio. A

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

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...

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.

Microalgae for Biofuels and Animal Feeds

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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.

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....

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

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

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

Enhancement of growth and lipid production from microalgae using fluorescent paint under the solar radiation.

Science.gov (United States)

Seo, Yeong Hwan; Cho, Changsoon; Lee, Jung-Yong; Han, Jong-In

2014-12-01

Solar radiation has intensity that is too high to inhibit microalgae activity and is composed of wide light spectrum including ultraviolet (UV) range which cannot be utilized for microalgae. For these reasons, the modification of solar radiation is required for effective microalgae cultivation, and to do that, fluorescent paint was used for not only blocking excessive solar energy but also converting UV to visible light. With fluorescent aqueous layer, microalgae was protected from photoinhibition and could grow well, but there was difference in growth and lipid accumulation efficiencies depending on the color; maximum dry weight of 1.7 g/L was achieved in red paint, whereas best lipid content of 30% was obtained in blue one. This phenomenon was due to the different light spectrum made by colors. With simple process using fluorescent paint, modification of light was successfully done and allowing microalgae to grow under strong radiation such as solar radiation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Current Status and Outlook in the Application of Microalgae in Biodiesel Production and Environmental Protection

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xin [Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan (China); University of Chinese Academy of Sciences, Beijing (China); Rong, Junfeng [SINOPEC Research Institute of Petroleum Processing, Beijing (China); Chen, Hui; He, Chenliu; Wang, Qiang, E-mail: wangqiang@ihb.ac.cn [Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan (China)

2014-08-19

Microalgae have been currently recognized as a group of the most potential feedstocks for biodiesel production due to high productivity potential, efficient biosynthesis of lipids, and less competition with food production. Moreover, utilization of microalgae with environmental purposes (CO{sub 2} fixation, NO{sub x}, and wastewater treatment) and biorefinery has been reported. However, there are still challenges that need to be addressed to ensure stable large-scale production with positive net energy balance. This review gives an overview of the current status of the application of microalgae in biodiesel production and environmental protection. The practical problems not only facing the microalgae biodiesel production but also associated with microalgae application for environmental pollution control, in particular biological fixation of greenhouse gas (CO{sub 2} and NO{sub x}) and wastewater treatment are described in detail. Notably, the synergistic combination of various applications (e.g., food, medicine, wastewater treatment, and flue gas treatment) with biodiesel production could enhance the sustainability and economics of the algal biodiesel production system.

Current status and outlook in the application of microalgae in biodiesel production and environmental protection

Directory of Open Access Journals (Sweden)

Xin eZhang

2014-08-01

Full Text Available Microalgae have been currently recognized as one group of the most potential feedstocks for biodiesel production due to high productivity potential, efficient biosynthesis of lipids and less competition with food production. Moreover, utilization of microalgae with environmental purposes (CO2 fixation, NOX and wastewater treatment and biorefinery have been reported. However, there are still challenges that need to be addressed to ensure stable large-scale production with positive net energy balance. This review gives an overview of the current status of the application of microalgae in biodiesel production and environmental protection. The practical problems not only facing the microalgae biodiesel production but also associated with microalgae application for environmental pollution control, in particular biological fixation of greenhouse gas (CO2 and NOX and wastewater treatment are described in detail. Notably, the synergistic combination of various applications (e.g. food, medicine, wastewater treatment and flue gas treatment with biodiesel production could enhance the sustainability and economics of the algal biodiesel production system.

Evaluation of lipid extractability after flash hydrolysis of algae

Energy Technology Data Exchange (ETDEWEB)

Teymouri, Ali; Adams, Kameron J.; Dong, Tao; Kumar, Sandeep

2018-07-01

Microalgae is identified as a promising feedstock for producing renewable liquid transportation fuels; however, lipids extraction from microalgae for downstream processing to biofuels is one of the important challenges for algal based biorefineries. This work aims at evaluating the potential of applying flash hydrolysis (FH) as a chemical-free technique to increase the lipids extractability of algal biomass as well as its integration with the hydrothermal liquefaction (HTL) of microalgae to enhance the biocrude yields and characteristics for fuel production. To this aim, the FH process was performed on three different algal species (Scenedesmus sp., Nannochloropsis sp., and Chlorella vulgaris) at 280 degrees C and 10 s of residence time. Following FH, in addition to the nutrients rich hydrolysate, approximately, 40 wt% of solids containing almost all (>90 wt%) the lipids termed as biofuels intermediates (BI), were recovered. Kinetics study on lipids extractability from the BI and their lipid profile analyses were conducted for each algal species. The results showed that the FH process had significantly enhanced the lipids extractability. For all three algae species, lipid yields from BI were higher than that of the raw algae. Lipid yields of Chlorella vulgaris in the first 15 min were more than five times higher (52.3 +/- 0.8 vs. 10.7 +/- 0.9 wt%) than that of raw algae during n-hexane based solvent extraction. The kinetics of lipids extractability followed a zero-order reaction rate for all wet raw microalgae and the BI of Scenedesmus sp., while the BI recovered from the other two algal species were determined as a second-order reaction. Comparison of fatty acids profiles indicated the contribution of the FH process in saturating fatty acids. Subsequent to lipids extraction, a conventional hydrothermal liquefaction was performed at 350 degrees C and 1 h to compare the biocrude yields from raw versus BI of Chlorella vulgaris microalgae. The results showed that the

Toxic pressure of herbicides on microalgae in Dutch estuarine and coastal waters

Science.gov (United States)

Booij, Petra; Sjollema, Sascha B.; van der Geest, Harm G.; Leonards, Pim E. G.; Lamoree, Marja H.; de Voogt, W. Pim; Admiraal, Wim; Laane, Remi W. P. M.; Vethaak, A. Dick

2015-08-01

For several decades now, there has been an increase in the sources and types of chemicals in estuarine and coastal waters as a consequence of anthropogenic activities. This has led to considerable concern about the effects of these chemicals on the marine food chain. The fact is that estuarine and coastal waters are the most productive ecosystems with high primary production by microalgae. The toxic pressure of specific phytotoxic chemicals now poses a major threat to these ecosystems. In a previous study, six herbicides (atrazine, diuron, irgarol, isoproturon, terbutryn and terbutylazine) were identified as the main contaminants affecting photosynthesis in marine microalgae. The purpose of this study is to investigate the toxic pressure of these herbicides in the Dutch estuarine and coastal waters in relation to the effective photosystem II efficiency (ΦPSII) in microalgae. Temporal and spatial variations in the concentrations of these herbicides were analyzed based on monitoring data. Additionally, a field study was carried out in which chemical analysis of water was performed and also a toxicity assessment using the Pulse Amplitude Modulation (PAM) fluorometry assay that measures ΦPSII. The toxic pressure on ΦPSII in microalgae has decreased with 55-82% from 2003 to 2012, with the Western Scheldt estuary showing the highest toxic pressure. By combining toxicity data from the PAM assay with chemical analysis of herbicide concentrations, we have identified diuron and terbutylazine as the main contributors to the toxic pressure on microalgae. Although direct effects are not expected, the toxic pressure is close to the 10% effect level in the PAM assay. A compliance check with the current environmental legislation of the European Union revealed that the quality standards are not sufficient to protect marine microalgae.

Microalgae wet extraction using N-ethyl butylamine for fatty acid production

Directory of Open Access Journals (Sweden)

Ying Du

2016-04-01

Full Text Available Microalgae are considered a promising feedstock for the production of food ingredients, cosmetics, pharmaceutical products and biofuels. The energy intensity of drying and cell breaking of algae and solvent recovery afterwards hindered the route of algae biorefinery. In this work the influences of freeze drying and cell breaking to the extraction efficiency of crude lipid yield and fatty acid yield were investigated. Results showed that drying and cell breaking are not necessary for N-ethyl butylamine extraction, because good yields were obtained without. Crude lipid yield and fatty acid yield using N-ethyl butylamine were comparable with Bligh & Dyer extraction, making N-ethyl butylamine a candidate for further development of an energy efficient lipid extraction technology for non-broken microalgae. Keywords: Microalgae, Lipids, Extraction, Switchable solvent, Secondary amine

Optimal control of nutrition restricted dynamics model of Microalgae biomass growth model

Science.gov (United States)

Ratianingsih, R.; Azim; Nacong, N.; Resnawati; Mardlijah; Widodo, B.

2017-12-01

The biomass of the microalgae is very potential to be proposed as an alternative renewable energy resources because it could be extracted into lipid. Afterward, the lipid could be processed to get the biodiesel or bioethanol. The extraction of the biomass on lipid synthesis process is very important to be studied because the process just gives some amount of lipid. A mathematical model of restricted microalgae biomass growth just gives 1/3 proportion of lipid with respect to the biomass in the synthesis process. An optimal control is designed to raise the ratio between the number of lipid formation and the microalgae biomass to be used in synthesis process. The minimum/ Pontryagin maximum principle is used to get the optimal lipid production. The simulation shows that the optimal lipid formation could be reach by simultaneously controlling the carbon dioxide, in the respiration and photosynthesis the process, and intake nutrition rates of liquid waste and urea substrate. The production of controlled microalgae lipid could be increase 6.5 times comparing to the uncontrolled one.

Isolation and evaluation of oil-producing microalgae from subtropical coastal and brackish waters.

Directory of Open Access Journals (Sweden)

David K Y Lim

Full Text Available Microalgae have been widely reported as a promising source of biofuels, mainly based on their high areal productivity of biomass and lipids as triacylglycerides and the possibility for cultivation on non-arable land. The isolation and selection of suitable strains that are robust and display high growth and lipid accumulation rates is an important prerequisite for their successful cultivation as a bioenergy source, a process that can be compared to the initial selection and domestication of agricultural crops. We developed standard protocols for the isolation and cultivation for a range of marine and brackish microalgae. By comparing growth rates and lipid productivity, we assessed the potential of subtropical coastal and brackish microalgae for the production of biodiesel and other oil-based bioproducts. This study identified Nannochloropsis sp., Dunaniella salina and new isolates of Chlorella sp. and Tetraselmis sp. as suitable candidates for a multiple-product algae crop. We conclude that subtropical coastal microalgae display a variety of fatty acid profiles that offer a wide scope for several oil-based bioproducts, including biodiesel and omega-3 fatty acids. A biorefinery approach for microalgae would make economical production more feasible but challenges remain for efficient harvesting and extraction processes for some species.

Moringa oleifera Seed Derivatives as Potential Bio-Coagulant for Microalgae Chlorella sp. Harvesting

International Nuclear Information System (INIS)

Azizah Endut; Azizah Endut; Siti Hajar Abdul Hamid; Fathurrahman Lananan; Helena Khatoon

2016-01-01

Microalgae is an economical and potential raw material of biomass energy, which offer a wide range of commercial potential to produce valuable substances for applications in aquaculture feed, pharmaceutical purposes and bio fuels production. However, lack of an economical, efficient and convenient method to harvest microalgae is a bottleneck to boost their full-scale application. Hence, this study was performed to investigate the potentialities of Moringa oleifera seed derivatives as an environmentally bio-coagulant to harvest microalgae Chlorella sp. biomass from the water column, which acts as a binder to coagulate particulate impurities to form larger aggregates. Results shown M. oleifera to have better biomass recovery of 122.51 % as compared to 37.08 % of alum at similar dosages of 10 mgL"-"1. In addition, it was found that the zeta potential values of mixed microalgae-coagulant suspension shows positive correlation on the flocculation parameters. For biomass recovery, the correlation for M. oleifera protein powder showed the R"2-value of 0.9565 whereas the control chemical flocculant, alum with the R"2-value of 0.7920. It was evidence that M. oleifera has a great potential in efficient and economical for environmentally microalgae harvesting and the adaptation of biological harvesting technology especially for the purpose of aquaculture feed in Malaysia. (author)

Modifications of the metabolic pathways of lipid and triacylglycerol production in microalgae

Directory of Open Access Journals (Sweden)

Yu Wei-Luen

2011-11-01

Full Text Available Abstract Microalgae have presented themselves as a strong candidate to replace diminishing oil reserves as a source of lipids for biofuels. Here we describe successful modifications of terrestrial plant lipid content which increase overall lipid production or shift the balance of lipid production towards lipid varieties more useful for biofuel production. Our discussion ranges from the biosynthetic pathways and rate limiting steps of triacylglycerol formation to enzymes required for the formation of triacylglycerol containing exotic lipids. Secondarily, we discuss techniques for genetic engineering and modification of various microalgae which can be combined with insights gained from research in higher plants to aid in the creation of production strains of microalgae.

Effective harvesting of the microalgae Chlorella protothecoides via bioflocculation with cationic starch

DEFF Research Database (Denmark)

Letelier Gordo, Carlos Octavio; Holdt, Susan Løvstad; De Francisci, Davide

2014-01-01

In the present work, the flocculation efficiency of cationic starch (Greenfloc 120) was tested on the fresh water microalga Chlorella protothecoides under different conditions (pH and flocculant concentrations). Different concentrations of Greenfloc 120 (0, 2.5, 5, 10, 20, 40mgL-1) were screened...... to use, efficient and cost-effective flocculant for harvesting of microalgae....

A Verhulst model for microalgae Botryococcus sp. growth and nutrient removal in wastewater

Science.gov (United States)

Jamaian, Siti Suhana; Bakeri, Noorhadila Mohd; Sunar, Norshuhaila Mohamed; Gani, Paran

2017-08-01

Microalgae Botryococcus sp. is a colonial green alga found in lakes and reservoirs in Malaysia. Previous studies reported that the potential of Botryococcus sp. photosynthesis as a source of fuel. The Botryococcus sp. contains hydrocarbon up to 75% of dry weight, which can be converted into petrol, diesel or turbine fuel or other liquid or gaseous hydrocarbons. Recently, an experimental study was conducted on phycoremediation technology for wastewater using Botryococcus sp. The phycoremediation technology is useful to remove the excess of nutrients such as nitrogen, phosphorus and also have the ability to remove various pollutants from wastewater. This research implements the Verhulst model to estimate the nutrient removal by microalgae Botryococcus sp. from the wastewater. This model has been validated with the experiments of microalgae Botryococcus sp. grown in domestic and palm oil wastewater. The results suggested that microalgae Botryococcus sp. could be cultured in domestic and palm oil wastewater while nutrients are reduced from these wastewaters.

Co-digestion of cultivated microalgae and sewage sludge from municipal waste water treatment.

Science.gov (United States)

Olsson, Jesper; Feng, Xin Mei; Ascue, Johnny; Gentili, Francesco G; Shabiimam, M A; Nehrenheim, Emma; Thorin, Eva

2014-11-01

In this study two wet microalgae cultures and one dried microalgae culture were co-digested in different proportions with sewage sludge in mesophilic and thermophilic conditions. The aim was to evaluate if the co-digestion could lead to an increased efficiency of methane production compared to digestion of sewage sludge alone. The results showed that co-digestion with both wet and dried microalgae, in certain proportions, increased the biochemical methane potential (BMP) compared with digestion of sewage sludge alone in mesophilic conditions. The BMP was significantly higher than the calculated BMP in many of the mixtures. This synergetic effect was statistically significant in a mixture containing 63% (w/w VS based) undigested sewage sludge and 37% (w/w VS based) wet algae slurry, which produced 23% more methane than observed with undigested sewage sludge alone. The trend was that thermophilic co-digestion of microalgae and undigested sewage sludge did not give the same synergy. Copyright © 2014 Elsevier Ltd. All rights reserved.

Microalgae dewatering based on forward osmosis employing proton exchange membrane.

Science.gov (United States)

Son, Jieun; Sung, Mina; Ryu, Hoyoung; Oh, You-Kwan; Han, Jong-In

2017-11-01

In this study, electrically-facilitated forward osmosis (FO) employing proton exchange membrane (PEM) was established for the purpose of microalgae dewatering. An increase in water flux was observed when an external voltage was applied to the FO equipped with the PEM; as expected, the trend became more dramatic with both concentration of draw solution and applied voltage raised. With this FO used for microalgae dewatering, 247% of increase in flux and 86% in final biomass concentration were observed. In addition to the effect on flux improvement, the electrically-facilitated FO exhibited the ability to remove chlorophyll from the dewatered biomass, down to 0.021±0015mg/g cell. All these suggest that the newly suggested electrically-facilitated FO, one particularly employed PEM, can indeed offer a workable way of dewatering of microalgae; it appeared to be so because it can also remove the ever-problematic chlorophyll from extracted lipids in a simultaneous fashion. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biodiesel production from microalgae: cultivation parameters that affect lipid production

International Nuclear Information System (INIS)

Arias Penaranda, Martha Trinidad; Martinez Roldan, Alfredo de Jesus; Canizares Villanueva, Rosa Olivia

2013-01-01

The microalgae have the capacity to mitigate CO 2 emissions and to produce lipids, which are considered with potential to obtain third-generation biofuel. This review provides updated information of the influence of culture conditions on the lipids production with high productivity and profile suitable for the biodiesel production. This document presents a compilation of research conclusions over the last 13 years around the world. in the literature consulted, the authors conclude that although the behavior of microalgae at physiological stress conditions, varies between species; the nutrients limitation, especially nitrogen and phosphorus, associated with heterotrophic growth or high irradiances in phototrophy are considered the most efficient strategies to increase the lipid content in microalgae, particularly triglycerides (consisting of saturated and monounsaturated fatty acids), which are excellent for the production of biodiesel. Also, it is reported that the lipid content increase and the number of unsaturated fatty acids decrease with the addition of small amounts of CO 2 and harvesting the biomass it the stationary phase of growth.

Innovative Alternative Technologies to Extract Carotenoids from Microalgae and Seaweeds.

Science.gov (United States)

Poojary, Mahesha M; Barba, Francisco J; Aliakbarian, Bahar; Donsì, Francesco; Pataro, Gianpiero; Dias, Daniel A; Juliano, Pablo

2016-11-22

Marine microalgae and seaweeds (microalgae) represent a sustainable source of various bioactive natural carotenoids, including β-carotene, lutein, astaxanthin, zeaxanthin, violaxanthin and fucoxanthin. Recently, the large-scale production of carotenoids from algal sources has gained significant interest with respect to commercial and industrial applications for health, nutrition, and cosmetic applications. Although conventional processing technologies, based on solvent extraction, offer a simple approach to isolating carotenoids, they suffer several, inherent limitations, including low efficiency (extraction yield), selectivity (purity), high solvent consumption, and long treatment times, which have led to advancements in the search for innovative extraction technologies. This comprehensive review summarizes the recent trends in the extraction of carotenoids from microalgae and seaweeds through the assistance of different innovative techniques, such as pulsed electric fields, liquid pressurization, supercritical fluids, subcritical fluids, microwaves, ultrasounds, and high-pressure homogenization. In particular, the review critically analyzes technologies, characteristics, advantages, and shortcomings of the different innovative processes, highlighting the differences in terms of yield, selectivity, and economic and environmental sustainability.

Innovative Alternative Technologies to Extract Carotenoids from Microalgae and Seaweeds

Science.gov (United States)

Poojary, Mahesha M.; Barba, Francisco J.; Aliakbarian, Bahar; Donsì, Francesco; Pataro, Gianpiero; Dias, Daniel A.; Juliano, Pablo

2016-01-01

Marine microalgae and seaweeds (microalgae) represent a sustainable source of various bioactive natural carotenoids, including β-carotene, lutein, astaxanthin, zeaxanthin, violaxanthin and fucoxanthin. Recently, the large-scale production of carotenoids from algal sources has gained significant interest with respect to commercial and industrial applications for health, nutrition, and cosmetic applications. Although conventional processing technologies, based on solvent extraction, offer a simple approach to isolating carotenoids, they suffer several, inherent limitations, including low efficiency (extraction yield), selectivity (purity), high solvent consumption, and long treatment times, which have led to advancements in the search for innovative extraction technologies. This comprehensive review summarizes the recent trends in the extraction of carotenoids from microalgae and seaweeds through the assistance of different innovative techniques, such as pulsed electric fields, liquid pressurization, supercritical fluids, subcritical fluids, microwaves, ultrasounds, and high-pressure homogenization. In particular, the review critically analyzes technologies, characteristics, advantages, and shortcomings of the different innovative processes, highlighting the differences in terms of yield, selectivity, and economic and environmental sustainability. PMID:27879659

Discoloration of wastewater from a paint industry by the microalgae Chlorella sp

Directory of Open Access Journals (Sweden)

Edgardo Angulo M

2017-09-01

Full Text Available Objective. Decoloring wastewater from a paint factory making use of Chlorella sp., microalgae as a biological way of treatment. Materials and methods. Samples of this microalgae previously cultivated with nourishing fertilizer under photoperiods of light and darkness were taken to test the microalgae Chlorella sp., initial concentration effect in the bioremoval process. For this purpose, it was cultivated in 0.10, 0.20 and 0.30 units of absorbance in bioreactors with 200 mL wastewater with and without nutrients. The biotest with the best rate of colour removal was chosen and the DBO5 and DQO were marked out. The immobilized Chlorella sp., in kappa carrageenan was also tested. Results. In the tests colour decrease percentage were 81.7, 69.7 and 58.3% without nutrients in the initial concentrations of 0.10, 0.20 and 0.30 units of absorbance respectively and 72.6, 69.0 and 86.8% for 0.10, 0.20 and 0.30 units of absorbance with nutrients respectively in the day of maximum growth. The immobilized microalgae score were 72.60% and 78.36% of color removal for 0.4 and 1.6 units of absorbance respectively. The higher colour removal test score was that with nutrients at 0.30 units of absorbance with several changes in DBO5 and DQO values. Conclusion. The biological wastewater treatment making use of Chlorella sp., microalgae can be considered as an effective choice in decolorating wastewater.

Strategies for Lipid Production Improvement in Microalgae as a Biodiesel Feedstock

Directory of Open Access Journals (Sweden)

L. D. Zhu

2016-01-01

Full Text Available In response to the energy crisis, global warming, and climate changes, microalgae have received a great deal of attention as a biofuel feedstock. Due to a high lipid content in microalgal cells, microalgae present as a promising alternative source for the production of biodiesel. Environmental and culturing condition variations can alter lipid production as well as chemical compositions of microalgae. Therefore, application of the strategies to activate lipid accumulation opens the door for lipid overproduction in microalgae. Until now, many original studies regarding the approaches for enhanced microalgal lipid production have been reported in an effort to push forward the production of microalgal biodiesel. However, the current literature demonstrates fragmented information available regarding the strategies for lipid production improvement. From the systematic point of view, the review highlights the main approaches for microalgal lipid accumulation induction to expedite the application of microalgal biodiesel as an alternative to fossil diesel for sustainable environment. Of the several strategies discussed, the one that is most commonly applied is the design of nutrient (e.g., nitrogen, phosphorus, and sulfur starvation or limitation. Other viable approaches such as light intensity, temperature, carbon dioxide, salinity stress, and metal influence can also achieve enhanced microalgal lipid production.

Effect of Metals, Metalloids and Metallic Nanoparticles on Microalgae Growth and Industrial Product Biosynthesis: A Review.

Science.gov (United States)

Miazek, Krystian; Iwanek, Waldemar; Remacle, Claire; Richel, Aurore; Goffin, Dorothee

2015-10-09

Microalgae are a source of numerous compounds that can be used in many branches of industry. Synthesis of such compounds in microalgal cells can be amplified under stress conditions. Exposure to various metals can be one of methods applied to induce cell stress and synthesis of target products in microalgae cultures. In this review, the potential of producing diverse biocompounds (pigments, lipids, exopolymers, peptides, phytohormones, arsenoorganics, nanoparticles) from microalgae cultures upon exposure to various metals, is evaluated. Additionally, different methods to alter microalgae response towards metals and metal stress are described. Finally, possibilities to sustain high growth rates and productivity of microalgal cultures in the presence of metals are discussed.

Bioprocess engineering of microalgae to produce a variety of consumer products

Energy Technology Data Exchange (ETDEWEB)

Harun, Razif [Bio Engineering Laboratory (BEL), Department of Chemical Engineering, Monash University, Victoria 3800 (Australia); Department of Chemical and Environmental Engineering, Universiti Putra Malaysia, 43400 Serdang (Malaysia); Singh, Manjinder; Forde, Gareth M.; Danquah, Michael K. [Bio Engineering Laboratory (BEL), Department of Chemical Engineering, Monash University, Victoria 3800 (Australia)

2010-04-15

Microalgae biotechnology has recently emerged into the lime light owing to numerous consumer products that can be harnessed from microalgae. Product portfolio stretches from straightforward biomass production for food and animal feed to valuable products extracted from microalgal biomass, including triglycerides which can be converted into biodiesel. For most of these applications, the production process is moderately economically viable and the market is developing. Considering the enormous biodiversity of microalgae and recent developments in genetic and metabolic engineering, this group of organisms represents one of the most promising sources for new products and applications. With the development of detailed culture and screening techniques, microalgal biotechnology can meet the high demands of food, energy and pharmaceutical industries. This review article discusses the technology and production platforms for development and creation of different valuable consumer products from microalgal biomass. (author)

Bioprocess engineering of microalgae to produce a variety of consumer products

International Nuclear Information System (INIS)

Harun, Razif; Singh, Manjinder; Forde, Gareth M.; Danquah, Michael K.

2010-01-01

Microalgae biotechnology has recently emerged into the lime light owing to numerous consumer products that can be harnessed from microalgae. Product portfolio stretches from straightforward biomass production for food and animal feed to valuable products extracted from microalgal biomass, including triglycerides which can be converted into biodiesel. For most of these applications, the production process is moderately economically viable and the market is developing. Considering the enormous biodiversity of microalgae and recent developments in genetic and metabolic engineering, this group of organisms represents one of the most promising sources for new products and applications. With the development of detailed culture and screening techniques, microalgal biotechnology can meet the high demands of food, energy and pharmaceutical industries. This review article discusses the technology and production platforms for development and creation of different valuable consumer products from microalgal biomass. (author)

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)

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

Management of a toxic cyanobacterium bloom (Planktothrix rubescens) affecting an Italian drinking water basin: a case study.

Science.gov (United States)

Bogialli, Sara; Nigro di Gregorio, Federica; Lucentini, Luca; Ferretti, Emanuele; Ottaviani, Massimo; Ungaro, Nicola; Abis, Pier Paolo; Cannarozzi de Grazia, Matteo

2013-01-02

An extraordinary bloom of Planktothrix rubescens, which can produce microcystins (MCs), was observed in early 2009 in the Occhito basin, used even as a source of drinking water in Southern Italy. Several activities, coordinated by a task force, were implemented to assess and manage the risk associated to drinking water contaminated by cyanobacteria. Main actions were: evaluation of analytical protocols for screening and confirmatory purpose, monitoring the drinking water supply chain, training of operators, a dedicated web site for risk communication. ELISA assay was considered suitable for health authorities as screening method for MCs and to optimize frequency of sampling according to alert levels, and as internal control for the water supplier. A liquid chromatography-tandem mass spectrometric method able to quantify 9 MCs was optimized with the aim of supporting health authorities in a comprehensive risk evaluation based on the relative toxicity of different congeners. Short, medium, and long-term corrective actions were implemented to mitigate the health risk. Preoxidation with chlorine dioxide followed by flocculation and settling have been shown to be effective in removing MCs in the water treatment plant. Over two years, despite the high levels of cyanobacteria (up to 160 × 10(6) cells/L) and MCs (28.4 μg/L) initially reached in surface waters, the drinking water distribution was never limited.

Combustion characteristics and air pollutant formation during oxy-fuel co-combustion of microalgae and lignite.

Science.gov (United States)

Gao, Yuan; Tahmasebi, Arash; Dou, Jinxiao; Yu, Jianglong

2016-05-01

Oxy-fuel combustion of solid fuels is seen as one of the key technologies for carbon capture to reduce greenhouse gas emissions. The combustion characteristics of lignite coal, Chlorella vulgaris microalgae, and their blends under O2/N2 and O2/CO2 conditions were studied using a Thermogravimetric Analyzer-Mass Spectroscopy (TG-MS). During co-combustion of blends, three distinct peaks were observed and were attributed to C. vulgaris volatiles combustion, combustion of lignite, and combustion of microalgae char. Activation energy during combustion was calculated using iso-conventional method. Increasing the microalgae content in the blend resulted in an increase in activation energy for the blends combustion. The emissions of S- and N-species during blend fuel combustion were also investigated. The addition of microalgae to lignite during air combustion resulted in lower CO2, CO, and NO2 yields but enhanced NO, COS, and SO2 formation. During oxy-fuel co-combustion, the addition of microalgae to lignite enhanced the formation of gaseous species. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chlorococcalean microalgae Ankistrodesmus convolutes biodiesel characterization with Fourier transform-infrared spectroscopy and gas chromatography mass spectroscopy techniques

Directory of Open Access Journals (Sweden)

Swati SONAWANE

2015-12-01

Full Text Available The Chlorococcalean microalgae Ankistrodesmus convolutes was found in fresh water Godawari reservoir, Ahmednagar district of Maharashtra State, India. Microalgae are modern biomass for the production of liquid biofuel due to its high solar cultivation efficiency. The collection, harvesting and drying processes were play vital role in converting algal biomass into energy liquid fuel. The oil extraction was the important step for the biodiesel synthesis. The fatty acid methyl ester (FAME synthesis was carried through base catalyzed transesterification method. The product was analyzed by using the hyphened techniques like Fourier Transform-Infrared spectroscopy (FT-IR and Gas Chromatography Mass Spectroscopy (GCMS. FT-IR Spectroscopy was results the ester as functional group of obtained product while the Gas Chromatography Mass Spectroscopy was results the six type of fatty acid methyl ester with different concentration. Ankistrodesmus convolutes biodiesel consist of 46.5% saturated and 49.14% unsaturated FAME.

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...

Recent Developments on Genetic Engineering of Microalgae for Biofuels and Bio-Based Chemicals.

Science.gov (United States)

Ng, I-Son; Tan, Shih-I; Kao, Pei-Hsun; Chang, Yu-Kaung; Chang, Jo-Shu

2017-10-01

Microalgae serve as a promising source for the production of biofuels and bio-based chemicals. They are superior to terrestrial plants as feedstock in many aspects and their biomass is naturally rich in lipids, carbohydrates, proteins, pigments, and other valuable compounds. Due to the relatively slow growth rate and high cultivation cost of microalgae, to screen efficient and robust microalgal strains as well as genetic modifications of the available strains for further improvement are of urgent demand in the development of microalgae-based biorefinery. In genetic engineering of microalgae, transformation and selection methods are the key steps to accomplish the target gene modification. However, determination of the preferable type and dosage of antibiotics used for transformant selection is usually time-consuming and microalgal-strain-dependent. Therefore, more powerful and efficient techniques should be developed to meet this need. In this review, the conventional and emerging genome-editing tools (e.g., CRISPR-Cas9, TALEN, and ZFN) used in editing the genomes of nuclear, mitochondria, and chloroplast of microalgae are thoroughly surveyed. Although all the techniques mentioned above demonstrate their abilities to perform gene editing and desired phenotype screening, there still need to overcome higher production cost and lower biomass productivity, to achieve efficient production of the desired products in microalgal biorefineries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study of Selecting on Light Source Used for Micro-algae Cultivation in Space

Science.gov (United States)

Ai, Weidang; Ai, Weidang; Guo, Shuang-Sheng; Gao, Feng; Tang, Yong-Kang; Qin, Li-Feng

To select suitable light source for micro-algae cultivation in future space station, the selected Spirulina plastensis(No.7) were cultured under different lightening qualities, including six light sources that were made up of different combinations of red and blue light-emitting diode(LED). The growth, photosynthetic efficiency and nutrition quality of the Spirulina, were analyzed. From the experiments, the red light may promote the cumulation of biomass of the Spirulina, and the cumulating rate was the highest under all red light source, but the syntheses of protein, phycobiliprotein, β-carotene, VE and other nutrients needs a certain portion of blue light; yet, the complete blue light condition is not favorable to the growth of Spirulina, and may bring pollution by chlorella and other kinds of micro-algae. It is concluded that the LEDs can be used as the light resource of micro-algae cultivation. The normal growth and development of microalgae need two light sources of both red and blue LEDs. The comprehensive analyses of the various factors that affect the growth of Spirulina, such as nutrition quality and photosynthetic activities, etc., showed that the combination of 80% red and 20% blue LED is the optimum one among those tested combinations. Key word: light-emitting diode; micro-algae; controlled ecological life support system (CELSS); space cultivation

hydroprocessing processing processing microalgae derived h