两株小球藻培养基的优化及其产EPA性能的研究

采用L18(37)正交法优化小球藻C95和小球藻C97的生长培养基,经15 L规模培养并收获小球藻;碱性乙醇法萃取游离脂肪酸,再经脲素包埋提取多不饱和脂肪酸,并用气相色谱检测二十碳五烯酸(eicosapentaenoic acid,EPA)的含量。研究结果表明:小球藻C95最优培养基(微量元素母液0.8 m L/L,维生素母液2.4 mL/L,NaH2PO4·2H2O6.0 g/L,Na2SiO3·9H2O 9.0 g/L,NaNO360.0 g/L,FeC6H5O7·5H2O 3.0 g/L);小球藻C97最优培养基(微量元素母液1.6 m L/L,维生素母液2.4 m L/L,NaH2PO4·2H2O 4.0 g/L,Na2SiO3·9H2O 11.0 g/L,NaNO380.0 g/L,FeC6H5O7·5H2O 3.0 g/L);小球藻C95和小球藻C97对数末期(分别是第4天和第5天)达到的细胞密度分别为9.53×10^7个/mL和8.91×10^7个/mL,EPA含量分别占总脂肪酸的30.2%和29.5%,小球藻C95的EPA含量要高于小球藻C97。

Optimizing Culture Medium for Two Chlorella Strains and Their EPA Production

L18(37)orthogonal methods were used to optimize growth media for Chlorella C95 and Chlorella C97,and then in those optimal media(15-liter scale)these two Chlorella strains were cultured and harvested.Free fatty acids were extracted in basic ethanol solvents,polyunsaturated fatty acids(PUFA)were concentrated by urea complexation,and finally the content of eicosapentaenoic acid(EPA)was determined by gas chromatography.Results showed that the optimal medium for Chlorella C95(trace element mother liquor 0.8 mL/L,vitamin mother liquor 2.4 mL/L,NaH2PO4·2H2O 6.0 g/L,Na2Si O3·9H2O 9.0 g/L,NaNO360.0 g/L,FeC6H5O7·5H2O 3.0 g/L);The optimal medium for Chlorella C97(trace element mother liquor 1.6 mL/L,vitamin mother liquor 2.4 mL/L,NaH2PO4·2 H2O 4.0 g/L,Na2Si O3·9H2O 11.0 g/L,NaNO380.0 g/L,FeC6H5O7·5H2O 3.0 g/L);at the end of logarithmic phase(the fourth growth day for Chlorella C95 and the fifth day for Chlorella C97),algae cell densities of Chlorella C95 and Chlorella C97 were 9.53×10^7/mL and 8.91×10^7/mL,respectively and the EPA contents account for 30.2%and 29.5%of total fatty acids,respectively.Chlorella C95 had higher EPA content than Chlorella C97.