The Experts below are selected from a list of 26364 Experts worldwide ranked by ideXlab platform
Feng Chen - One of the best experts on this subject based on the ideXlab platform.
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rapid screening method for lipid production in alga based on nile red fluorescence
Biomass & Bioenergy, 2009Co-Authors: Guanhua Huang, Gu Chen, Feng ChenAbstract:Abstract As a promising source of biodiesel, Chlorella has drawn more and more attention of researcher, while rapid screening of enhanced lipid production becomes essential. Here we investigated lyophilized alga powders as the starting material and optimized Nile red method for quantitative measurement of neutral lipids in Chlorella with a high correlation coefficient ( R 2 = 0.99) between gravimetric and spectrofluorimetric quantification. Using this method, Chlorella vulgaris were screened out of several Chlorella strains with the highest lipid content and orthogonal design experiments were performed to search for the significant factors affecting lipid accumulation. Our data implied that the sensitivity and versatility enable this method a useful tool in optimizing culture and accumulation condition of lipid production in alga and figured out several factors significantly influenced lipid production in C. vulgaris.
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isolation and purification of lutein from the microalga Chlorella vulgaris by extraction after saponification
Journal of Agricultural and Food Chemistry, 2002Co-Authors: Huabin Li, Yue Jiang, Feng ChenAbstract:A simple and efficient method for the isolation and purification of lutein from the microalga Chlorella vulgaris was developed. Crude lutein was obtained by extraction with dichloromethane from the microalga after saponification. Partition values of lutein in the two-phase system of ethanol−water−dichloromethane at different ratios were measured by HPLC so as to assist the determination of an appropriate condition for washing water-soluble impurities in the crude lutein. Partition values of lutein in another two-phase system of ethanol−water−hexane at different ratios were also measured by HPLC for determining the condition for removing fat-soluble impurities. The water-soluble impurities in the crude lutein were removed by washing with 30% aqueous ethanol, and the fat-soluble impurities were removed by extraction with hexane. The final purity of lutein obtained was 90−98%, and the yield was 85−91%. Keywords: Lutein; purification; Chlorella vulgaris; saponification; extraction
Shigeyuki Kawano - One of the best experts on this subject based on the ideXlab platform.
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starch and lipid accumulation in eight strains of six Chlorella species under comparatively high light intensity and aeration culture conditions
Bioresource Technology, 2014Co-Authors: Tsuyoshi Takeshita, Shuhei Ota, Tomokazu Yamazaki, Aiko Hirata, Vilem Zachlede, Shigeyuki KawanoAbstract:Abstract The microalgae family Chlorella species are known to accumulate starch and lipids. Although nitrogen or phosphorous deficiencies promote starch and lipids formation in many microalgae, these deficiencies also limit their growth and productivity. Therefore, the Chlorellaceae strains were attempted to increase starch and lipids productivity under high-light-intensity conditions (600-μmol photons m−2 s−1). The 12:12-h light–dark (LD) cycle conditions elicited more stable growth than the continuous light (LL) conditions, whereas the starch and lipids yields increased in LL conditions. The amount of starch and lipids per cell increased in Chlorella viscosa and Chlorella vulgaris in sulfur-deficient medium, and long-chain fatty acids with 20 or more carbon atoms accumulated in cells grown in sulfur-deficient medium. Accumulation of starch and lipids was investigated in eight strains. The accumulation was strain-dependent, and varied according to the medium and light conditions. Five of the eight Chlorella strains exhibited similar accumulation patterns.
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sequential accumulation of starch and lipid induced by sulfur deficiency in Chlorella and paraChlorella species
Bioresource Technology, 2013Co-Authors: Yusuke Mizuno, Tsuyoshi Takeshita, Shuhei Ota, Aiko Hirata, Vilem Zachlede, Atsushi Sato, Koichi Watanabe, Norihiro Sato, Mikio Tsuzuki, Shigeyuki KawanoAbstract:The influence of sulfur deficiency on biomass production was analyzed in the four Chlorellaceae species, Chlorella vulgaris, Chlorella sorokiniana, Chlorella lobophora, and ParaChlorella kessleri. Culturing under sulfur-deficient conditions promoted transient accumulation of starch followed by a steady increase in lipid storage. Transmission electron microscopy indicated an increase and decrease in starch granules and subsequent enlargement of lipid droplets under sulfur-deficient conditions. Chlorellaceae spp. accumulated 1.5–2.7-fold higher amounts of starch and 1.5–2.4-fold higher amounts of lipid under sulfur-deficient conditions than under sulfur-sufficient conditions. More than 75% of the fatty acids that accumulated in Chlorellaceae spp. under the sulfur-sufficient condition were unsaturated and culturing under sulfur-deficient conditions increased the saturated fatty acid content from 24.3% to 59.7% only in P. kessleri. These results indicate that the sequential accumulation of starch and lipid is a response to the sulfur depletion that commonly occurs in Chlorellaceae spp.
Josef Komenda - One of the best experts on this subject based on the ideXlab platform.
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photoadaptation of two members of the chlorophyta scenedesmus and Chlorella in laboratory and outdoor cultures changes in chlorophyll fluorescence quenching and the xanthophyll cycle
Planta, 1999Co-Authors: Jiři Masojidek, Jiři Kopecký, Angelo Sacchi, Paola Bernardini, Giuseppe Torzillo, Michal Kobližek, Josef KomendaAbstract:The role of the xanthophyll cycle in the adaptation of two chlorococcal algae Scenedesmus quadricauda and Chlorella sorokiniana to high irradiance was studied under laboratory and outdoor conditions. We wished to elucidate whether the xanthophyll cycle plays a key role in dissipating the excesses of absorbed light, as in higher plants, and to characterise the relationship between chlorophyll fluorescence parameters and the content of xanthophyll-cycle pigments. The xanthophyll cycle was found to be operative in both species; however, its contribution to overall non-photochemical quenching (NPQ) could only be distinguished in Scenedesmus (15–20% of total NPQ). The Scenedesmus cultures showed a larger pool of xanthophyll-cycle pigments than Chlorella, and lower sensitivity to photoinhibition as judged from the reduction of maximum quantum yield of photosystem II. In general, both algae had a larger xanthophyll-cycle pool when grown outdoors than in laboratory cultures. Comparing the two species, Scenedesmus exhibited a higher capacity to adapt to high irradiance, due to an effective quenching mechanism and high photosynthetic capacity; in contrast, Chlorella represents a species with a larger antennae system, less-efficient quenching and lower photosynthetic performance. Non-photochemical quenching (NPQ) induced through the xanthophyll cycle can, to a limited extent, represent a regulatory factor in diluted algal cultures grown in outdoor solar photobioreactors, as well as in natural algal phytoplankton populations exposed transiently to high irradiance. However, it does not play an appreciable role in dense, well-mixed microalgal suspensions.
Roger Ruan - One of the best experts on this subject based on the ideXlab platform.
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enhanced mixotrophic growth of microalga Chlorella sp on pretreated swine manure for simultaneous biofuel feedstock production and nutrient removal
Bioresource Technology, 2012Co-Authors: Bing Hu, Wenguang Zhou, Paul Chen, Roger Ruan, Zhenyi Du, Michael Mohr, Yanling ChengAbstract:Abstract The objectives were to assess the feasibility of using fermented liquid swine manure (LSM) as nutrient supplement for cultivation of Chlorella sp. UMN271, a locally isolated facultative heterotrophic strain, and to evaluate the nutrient removal efficiencies by alga compared with those from the conventionally decomposed LSM–algae system. The results showed that addition of 0.1% (v/v) acetic, propionic and butyric acids, respectively, could promote algal growth, enhance nutrient removal efficiencies and improve total lipids productivities during a 7-day batch cultivation. Similar results were observed when the acidogenic fermentation was applied to the sterilized and raw digested LSM rich in volatile fatty acids (VFAs). High algal growth rate (0.90 d −1 ) and fatty acid content (10.93% of the dry weight) were observed for the raw VFA-enriched manure sample. Finally, the fatty acid profile analyses showed that Chlorella sp. grown on acidogenically digested manure could be used as a feedstock for high-quality biodiesel production.
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integration of algae cultivation as biodiesel production feedstock with municipal wastewater treatment strains screening and significance evaluation of environmental factors
Bioresource Technology, 2011Co-Authors: Yecong Li, Wenguang Zhou, Bing Hu, Paul Chen, Roger RuanAbstract:Abstract The objectives of this study are to find the robust strains for the centrate cultivation system and to evaluate the effect of environmental factors including light intensity, light–dark cycle, and exogenous CO 2 concentration on biomass accumulation, wastewater nutrient removal and biodiesel production. The results showed that all 14 algae strains from the genus of Chlorella , Haematococcus , Scenedesmus , Chlamydomonas , and Chloroccum were able to grow on centrate. The highest net biomass accumulation (2.01 g/L) was observed with Chlorella kessleri followed by Chlorella protothecoides (1.31 g/L), and both of them were proved to be capable of mixotrophic growth when cultivated on centrate. Environmental factors had significant effect on algal biomass accumulation, wastewater nutrients removal and biodiesel production. Higher light intensity and exogenous CO 2 concentration with longer lighting period promote biomass accumulation, biodiesel production, as well as the removal of chemical oxygen demand and nitrogen, while, lower exogenous CO 2 concentration promotes phosphorus removal.
Amitava Mukherjee - One of the best experts on this subject based on the ideXlab platform.
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studies on toxicity of aluminum oxide al 2 o 3 nanoparticles to microalgae species scenedesmus sp and Chlorella sp
Journal of Nanoparticle Research, 2011Co-Authors: Mohammed I Sadiq, Sunanda Pakrashi, N Chandrasekara, Amitava MukherjeeAbstract:In view of increasing commercial applications of metal oxide nanoparticles their toxicity assessment becomes important. Alumina (Al2O3) nanoparticles have wide range of applications in industrial as well as personal care products. In the absence of prior report on toxicological impact of alumina nanoparticles to microalgae, the principal objective of this study was to demonstrate the effect of the nanoparticles on microalgae isolated from aquatic environment (Scenedesmus sp. and Chlorella sp.). The growth inhibitory effect of alumina nanoparticles was observed for both the species (72 h EC50 value, 45.4 mg/L for Chlorella sp.; 39.35 mg/L for Scenedesmus sp.). Bulk alumina also showed toxicity though to a lesser extent (72 h EC50 value, 110.2 mg/L for Chlorella sp.; 100.4 mg/L for Scenedesmus sp.). A clear decrease in chlorophyll content was observed in the treated cells compared to the untreated ones, more effect being notable in the case of nanoparticles. Preliminary results based on FT-IR studies, optical and scanning electron microscopic images suggest interaction of the nanoparticles with the cell surface.