Outdoor Cultivation Oil Extraction of the Salt-tolerant Microalga,Eustigmatos sp.

doi:10.13560/j.cnki.biotech.bull.1985.2019-1050

Abstract

Abstract: Due to the fast growth and the ability of accumulating high content of microalgal oil and polyunsaturated fatty acids,Eustigmatos sp. has received widespread attention from microalgal scientists. Assessing its outdoor cultivation and exploring oil extraction from Eustigmatos are considered as the key to its industrialization. Two kinds of light path self-made flat-plate photobioreactors were used to evaluate the productivity of Eustigmatos sp. SCSIO-45821,which was isolated from the Ningxia Autonomous Region by measuring its growth,lipid accumulation,and fatty acid composition. Moreover,the method of oil extraction by ethanol was investigated. Results showed that Eustigmatos sp. SCSIO-45821 grew normally in the flat-plate photobioreactors. The light path of 6 cm flat-plate photobioreactors was suitable for the production of Eustigmatos biomass being rich in eicosapentaenoic acid（EPA）. The highest average productivity of biomass and EPA was 93.5 mg/L·d and 0.6 mg/L·d,respectively. However,the light path of 4 cm flat-plate photobioreactor was more conducive to oil accumulation,and the lipid productivity was 22.0 mg/L·d. Ethanol was used for the extraction of oil from the biomass of Eustigmatos. The optimal condition for oil extraction included：100% ethanol,room temperature and more than 36 h for extraction,and under which the highest extraction rate reached 94.3%. The extracted oil contained > 70% neutral lipid in total lipid and 4.0% EPA in total fatty acid. However,the Eustigmatos oil showed black color and needed to be decolorized and refined. In sum,the outdoor flat-plate photobioreactor is an ideal device for cultivating Eustigmatos sp. However,it is necessary to select a suitable light path according to the target product. Ethanol can be used as an ideal solvent for extracting oil from Eustigmatos oil.

Key words: Eustigmatos, microalgae oil, flat-plate photobioreactors, productivity, oil extraction

LI Tao, ZHAO Wei, YANG Bing-Jie, CHEN Zi-Shuo, WU Hua-lian, WU Hou-bo, XIANG Wen-zhou. Outdoor Cultivation Oil Extraction of the Salt-tolerant Microalga,Eustigmatos sp.[J]. Biotechnology Bulletin, 2020, 36(7): 130-138.

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