Growth,Lipid Accumulation,and Fat Composition of Eustigmatos sp. Under Different Nitrogen Source and Concentration

doi:10.13560/j.cnki.biotech.bull.1985.2019-0009

Abstract

Abstract: Eustigmatophyceae can accumulate high content of eicosapntemacnioc acid（EPA）,which is of great value for development and utilization. The aims of the present work are to investigate the effects of different nitrogen sources and concentrations on the growth,fat accumulation and fatty acid composition of Eustigmatos sp. tolerating high salt. Using G-11 as basic medium,3 nitrogen sources（sodium nitrate,urea,and bicarbonate）were selected and 3 nitrogen concentrations（3.5 mmol/L,5.9 mmol/L and 17.6 mmol/L）for each nitrogen source were set,the time-course changes in biomass,total lipids content,fat classification and fatty acid composition of Eustigmatos sp. were traced and determined. The results showed that the highest biomass concentration of Eustigmatos sp. was 7.07 g/L while ammonium bicarbonate（17.6 mmol/L）as nitrogen source. The total lipids yield by 3 nitrogen sources at 3.5 mmol/L was higher than that at 5.9 mmol/L and 17.6 mmol/L,and while under 3.5 mmol/L it was the highest 4.18 g/L by urea as nitrogen source,following 4.07 g/L by sodium nitrate,and the lowest 3.42 g/L by ammonium bicarbonate. Nitrogen deficiency increased the proportion of neutral lipids in Eustigmatos sp. The proportion of neutral lipids at 3.5 mmol/L was higher than that at 5.9 mmol/L and 17.6 mmol/L. At 3.5 mmol/L condition,the content of neutral lipids in urea group,ammonium bicarbonate group and sodium nitrate group were 79.0% TL（total lipids）,77.0% TL and 75.7% TL,respectively. The fatty acid composition of Eustigmatos sp. was mainly C14∶0（myristic acid）,C16∶0（palmitic acid）,C16∶1（palmitoleic acid）,C18∶1（oleic acid）,C18∶2（linoleic acid）,C20∶4（arachidonic acid）and C20∶5（EPA）. The content of C16∶1 was 51% in total acid fatty（TFA）. The highest percentage of C20∶5（EPA）was at 17.6 mmol/L,7.18% TFA by sodium nitrate,followed by 6.20% TFA by urea and the lowest 4.82% TFA by ammonium bicarbonate. In conclusion,Eustigmatos sp. presents great development potential.

Key words: Eustigmatos, growth, total lipid, fatty acid, nitrogen source

ZHAO Wei, LI Tao, WU Hua-lian, CHEN Hao, LIU De-Hai, XIANG Wen-zhou, WU Hou-bo. Growth,Lipid Accumulation,and Fat Composition of Eustigmatos sp. Under Different Nitrogen Source and Concentration[J]. Biotechnology Bulletin, 2019, 35(6): 62-68.

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