| 摘要: |
| 以1.4cm和2.8cm光径的平板光生物反应器, 恒定高光强[ 2400μE/( m2?s) ] , 通气、无菌高密度连续培养雪地绿藻( 简称雪藻) 。连续采收并补充等量新鲜培养液, 当藻体生物量(以去灰分干重表示, AFDW) 达恒态时, 研究雪藻比生长速率( SGR ) 、藻体的生物产量、总脂肪酸( TFA) 和花生四烯酸( AA) 产率。结果表明, 尽管随着比生长速率增加, 雪藻高密度连续培养体系的AA/ TFA、TFA/ AFDW 和AA/ AFDW 三个指标有不同程度的降低, 但生物产量、总脂肪酸及其花生四烯酸产出都相当高。2.8cm光径的平板光生物反应器中, 雪藻SGR为0.2d-1时, 每平方米光照面积日获35.3g AFDW 的高产量; SGR 0.135d-1时, TFA 产率最大, 为7.0g/(m2?d) , 此时AA 产率也最高, 达2.6g /(m2?d) 。尽管1.4cm 光径的反应器的培养体积比前者下降了50%, 但细胞浓度明显提高, 单位光照面积的AFDW 和TFA 最大日产率只下降了37.3%和10%, 分别为22.1 和6.3g/( m2?d) , 而AA 的最大日产率也是2.6g/(m2?d) 。结果还表明, 氮或磷营养亏缺能明显提高雪藻AA 含量的各项指标, 同时高光强也有利于雪藻累积AA。 |
| 关键词: 雪藻, 高密度培养, 平板光生物反应器, 花生四烯酸, 产率, 比生长速率 |
| DOI： |
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| 基金项目:国家自然科学基金资助项目, 39500114 号, 39970575 号; 国际科学基金项目, A/2786-1 号,A/2786-2 号。 |
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| THE HIGH PRODUCTIVITY OF BIOMASS AND ARACHIDONIC ACID IN CONTINUOUS HIGH DENSITY CULTURE OF PARIETOCHLORIS INCISA |
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LIU Jian-Guo1, LIU Wei1, Zvi Cohen2, Amos Richmond2
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1.R&D Center of Marine Biotechnology, Institute of Oceanology, The Chinese Academy of Sciences;2.Microalgal Biotechnology , The Jacob Blaustein Institute for Desert Research,Ben-Gurion University of the Negev, Sede Boker Campus 84994
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| Abstract: |
| Parietochloris incise is a species of cryophilic green microalgae, which is economically valuable and has a unique ability to accumulate large amount of arachidonic acid. Some physiological profiles like specific growth rate (SGR) , ash free dry weigh ( AFDW) , total fatty acids ( TFA) and arachidonic acid ( AA) in axenic high density culture of this alga were closely studied by using 1.4cm and 2.8cm light-path flat-photobioreactors. The culture was vigorously aerated and exposed to strong photon flux density [ ca. 2400μE/( m2?s) ]. Culture was partly harvested daily and the same volume of fresh medium was added into the culture system.
Data showed that very high productions of biomass, TFA and AA were observed from the flat-photobioreactor systems, although the main profiles ( AA/ TFA, TFA/ AFD and AA/ AFDW) decreased in varied content with a similar pattern concomitant with the increase of SGR. Maximal biomass production [ AFDW, 35.3g/ (m2?d) ] and TFA production [ 7.0g/(m2?d) ] were obtained in 2.8cm light-path photobioreactor when the SGR were at 0.2d-1 and 0.135d-1. The highest ratio of AA/AFDW was observed when the SGR was at 0.1d-1, while the AA production [ 2.6g/(m2?d) ] reached to its maximum when the SGR of the culture was at 0.135d-1. The maximal TFA production and biomass production in the narrow light-path photobioreactor ( 1.4cm) were 10% and 37.3% less than that of the thick one ( 2.8cm) , though the culture volume was only half. The maximal AA production of two photobioreactors was the same mainly because of the increase of biomass density in narrow light-path photobioreactor and partly due to the increase in AA/AFDW profile.
The studies also indicated that nitrate-or phosphate-deficiency accelerated the AA accumulation in the cells, and strong light intensity favored the AA accumulation. |
| Key words: Parietochloris incisa, High density culture, Flat-photobioreactor, Arachidonic acid, Productivity, Specific growth rate |
