The relative contents of normal alkanes and isoprenoid alkanes from pyrolysed products of green alga Chlorella protothecoides increased when the algal cell subject to hydrolysis and bacterial degradation were used. Th...The relative contents of normal alkanes and isoprenoid alkanes from pyrolysed products of green alga Chlorella protothecoides increased when the algal cell subject to hydrolysis and bacterial degradation were used. Their value of C 23 -/C 24 + and the rate of Pr/C 17 increased greatly whereas the contents of C 20 alkenes were remarkably low compared with that from untreated sample (as control). These results are more analogous to the formation process of hydrocarbons derived from algae in natural geological environment.展开更多
The fast growing unicellular green microalgae Chlorella protothecoides has attracted interest as a promising organism for commercial production of a high-value carotenoid,lutein,by heterotrophic fermentation.Effects o...The fast growing unicellular green microalgae Chlorella protothecoides has attracted interest as a promising organism for commercial production of a high-value carotenoid,lutein,by heterotrophic fermentation.Effects of two oxidant-forming reactive oxygen species(ROS)on the biomass concen-tration,and yield and content of lutein in batch culture of heterotrophic Chlorella protothecoides were investigated in this study.The addition of 0.1 mmol/L H2O2 and 0.01 mmol/L NaClO plus 0.5 mmol/L Fe2+to the culture led to the generation of·OH and enhanced the lutein content from 1.75 to 1.90 and 1.95 mg/g,respectively.The lutein content further increased to 1.98 mg/g when 0.01 mmol/L H2O2 and 0.5 mmol/L NaClO were added to generate 1O2.The maximum yield of lutein(28.5,29.8 and 31.4 mg/L)and a high biomass concentration(15.0,15.3 and 15.9 g/L)were also achieved through the above treatments.The results indicated that 1O2 could promote lutein formation and enhance lutein production in hetero-trophic Chlorella protothecoides.Moreover,1O2 produced from the reaction of H2O2 and NaClO was more effective in enhancing lutein production and reducing biomass loss than·OH from the reaction of H2O2 or NaClO plus Fe2+.展开更多
Effects of inhibitors and glucose on cytochrome and alternative respiration and on adenylate energy charge (AEC) in glucose starved Chlorella protothecoides were investigated. 1 mmol/L azide (NaN 3), which immediate...Effects of inhibitors and glucose on cytochrome and alternative respiration and on adenylate energy charge (AEC) in glucose starved Chlorella protothecoides were investigated. 1 mmol/L azide (NaN 3), which immediately caused an increase of O 2 uptake by inhibiting the cytochrome pathway and stimulating alternative respiration, resulted in a decrease of AEC value from 0.83 to 0.34 within 3 minutes. When 1 mmol/L salicylhydroxamic acid (SHAM) was added into the cell suspension, there was no apparent variation in AEC. Adding NaN 3 and SHAM together into cell suspension to inhibit both cytochrome and alternative pathways showed a same change of AEC as that of adding NaN 3 alone. When 2.0 mmol/L of glucose was added to a suspension of glucose starved cells, the O 2 uptake rate was immediately stimulated from 0.81 up to 1.34 [μmol/L O 2[DK]·min -1 ·(mL PCV) -1 ]. The respiration stimulated by glucose could be inhibited about 20% by adding 1 mmol/L SHAM. It was found by titration with SHAM in the absence and presence of NaN 3 that 53% of O 2 uptake went through the cytochrome pathway and 45% of the alternate pathway was operational in enhanced respiration. It implied that induced operation of the alternative respiratory pathway probably resulted from the burst of the electron flux into the electron transport chain by glucose stimulation. . The respiration stimulated by glucose could be inhibited about 20% by adding 1 mmol/L SHAM. It was found by titration with SHAM in the absence and presence of NaN 3 that 53% of O 2 uptake went through the cytochrome pathway and 45% of the alternate pathway was operational in enhanced respiration. It implied that induced operation of the alternative respiratory pathway probably resulted from the burst of the electron flux into the electron transport chain by glucose stimulation.展开更多
Effects of nitrogen source and concentration as well as lipid extraction method on the lipid yield of autotrophic Scenedesmus dimorphus and heterotrophic Chlorella protothecoides were studied.Three concentration level...Effects of nitrogen source and concentration as well as lipid extraction method on the lipid yield of autotrophic Scenedesmus dimorphus and heterotrophic Chlorella protothecoides were studied.Three concentration levels of nitrate,urea and glycine/yeast extract as the nitrogen source were investigated.The highest lipid yield of S.dimorphus in the 17-d autotrophic culture was 0.40 g/L from the 1.8 g/L urea medium,and the maximum lipid yield of C.protothecoides in the nine-day heterotrophic culture was 5.89 g/L from the 2.4 g/L nitrate medium.Four different cell disruption methods-bead-beater,French press,sonication and wet milling-were studied for their effectiveness in solvent extraction of algal lipids from S.dimorphus and C.protothecoides.Wet milling followed by hexane extraction was most effective for S.dimorphus lipid extraction,whereas bead-beater disruption followed by hexane extraction was best for C.protothecoides.展开更多
文摘The relative contents of normal alkanes and isoprenoid alkanes from pyrolysed products of green alga Chlorella protothecoides increased when the algal cell subject to hydrolysis and bacterial degradation were used. Their value of C 23 -/C 24 + and the rate of Pr/C 17 increased greatly whereas the contents of C 20 alkenes were remarkably low compared with that from untreated sample (as control). These results are more analogous to the formation process of hydrocarbons derived from algae in natural geological environment.
基金Supported by the National Key Project of Sci&Tech Supporting ProgramsFunded by Ministry of Science&Technology of China(Grant No.2006BAD27B03)+1 种基金Sci&Tech Project of Guangzhou(Grant No.2005Z3-E0331)Sci&Tech Project of Guangdong(Grant No.20052050166)
文摘The fast growing unicellular green microalgae Chlorella protothecoides has attracted interest as a promising organism for commercial production of a high-value carotenoid,lutein,by heterotrophic fermentation.Effects of two oxidant-forming reactive oxygen species(ROS)on the biomass concen-tration,and yield and content of lutein in batch culture of heterotrophic Chlorella protothecoides were investigated in this study.The addition of 0.1 mmol/L H2O2 and 0.01 mmol/L NaClO plus 0.5 mmol/L Fe2+to the culture led to the generation of·OH and enhanced the lutein content from 1.75 to 1.90 and 1.95 mg/g,respectively.The lutein content further increased to 1.98 mg/g when 0.01 mmol/L H2O2 and 0.5 mmol/L NaClO were added to generate 1O2.The maximum yield of lutein(28.5,29.8 and 31.4 mg/L)and a high biomass concentration(15.0,15.3 and 15.9 g/L)were also achieved through the above treatments.The results indicated that 1O2 could promote lutein formation and enhance lutein production in hetero-trophic Chlorella protothecoides.Moreover,1O2 produced from the reaction of H2O2 and NaClO was more effective in enhancing lutein production and reducing biomass loss than·OH from the reaction of H2O2 or NaClO plus Fe2+.
基金the National Natural Science Foundationof China(No. 39870 0 6 4and30 0 70 0 6 5 ) partly bythe State Key Basic Research and Developm entProgram s of China(No.G19980 10 10 0 and G19990 433)
文摘Effects of inhibitors and glucose on cytochrome and alternative respiration and on adenylate energy charge (AEC) in glucose starved Chlorella protothecoides were investigated. 1 mmol/L azide (NaN 3), which immediately caused an increase of O 2 uptake by inhibiting the cytochrome pathway and stimulating alternative respiration, resulted in a decrease of AEC value from 0.83 to 0.34 within 3 minutes. When 1 mmol/L salicylhydroxamic acid (SHAM) was added into the cell suspension, there was no apparent variation in AEC. Adding NaN 3 and SHAM together into cell suspension to inhibit both cytochrome and alternative pathways showed a same change of AEC as that of adding NaN 3 alone. When 2.0 mmol/L of glucose was added to a suspension of glucose starved cells, the O 2 uptake rate was immediately stimulated from 0.81 up to 1.34 [μmol/L O 2[DK]·min -1 ·(mL PCV) -1 ]. The respiration stimulated by glucose could be inhibited about 20% by adding 1 mmol/L SHAM. It was found by titration with SHAM in the absence and presence of NaN 3 that 53% of O 2 uptake went through the cytochrome pathway and 45% of the alternate pathway was operational in enhanced respiration. It implied that induced operation of the alternative respiratory pathway probably resulted from the burst of the electron flux into the electron transport chain by glucose stimulation. . The respiration stimulated by glucose could be inhibited about 20% by adding 1 mmol/L SHAM. It was found by titration with SHAM in the absence and presence of NaN 3 that 53% of O 2 uptake went through the cytochrome pathway and 45% of the alternate pathway was operational in enhanced respiration. It implied that induced operation of the alternative respiratory pathway probably resulted from the burst of the electron flux into the electron transport chain by glucose stimulation.
文摘小球藻Chlorella protothecoides(C.protothecoides)是潜在的、可用于工业生产生物柴油的高产油微藻.本研究通过体外诱变的手段,获得了一株完全不能进行光合自养生长的突变体Al64.利用尼罗红染色和叶绿素自发荧光分析和电子显微镜分析细胞的亚显微结构,结果显示该突变体中叶绿体严重退化,其中类囊体膜结构缺失,导致该突变体缺乏叶绿素,无法进行光合自养生长.在富糖富氮的培养条件下,该光合自养缺陷型突变体的细胞密度和油脂含量比野生型细胞分别高5.54%和6.76%,分析还发现,该突变体产油能力为0.158 g L?1 h?1,比野生型提高12.8%.本文通过缺失光合作用突变体的构建,在异养高氮条件下实现了生物量及细胞内油脂含量的同步提高,为进一步提高微藻生产生物柴油的产量提供了新的研究平台.
基金the use of some equipment.This research is funded by NSF(Award CMMI-0836610)Kansas Agricultural Experiment Station(Contribution No.09-237-J from the Kansas Agricultural Experiment Station).
文摘Effects of nitrogen source and concentration as well as lipid extraction method on the lipid yield of autotrophic Scenedesmus dimorphus and heterotrophic Chlorella protothecoides were studied.Three concentration levels of nitrate,urea and glycine/yeast extract as the nitrogen source were investigated.The highest lipid yield of S.dimorphus in the 17-d autotrophic culture was 0.40 g/L from the 1.8 g/L urea medium,and the maximum lipid yield of C.protothecoides in the nine-day heterotrophic culture was 5.89 g/L from the 2.4 g/L nitrate medium.Four different cell disruption methods-bead-beater,French press,sonication and wet milling-were studied for their effectiveness in solvent extraction of algal lipids from S.dimorphus and C.protothecoides.Wet milling followed by hexane extraction was most effective for S.dimorphus lipid extraction,whereas bead-beater disruption followed by hexane extraction was best for C.protothecoides.
