The change regulations of biomass and fatty acid contents of Schizochytrium sp. A3-9 were studied under different fermentation conditions. The results showed that the optimal fermentation conditions for biomass accumulation of Schizochytrium sp. were as follows: initial glucose content 90 g/L and carbon-nitrogen ratio 8. Under the optimal condition, the biomass could reach 38.12 g/L, which was 104.59％ higher than that of the control group. The optimal fermentation conditions for total fatty acid accumulation were as follows: liquid loading volume 220 ml/500 ml, citric acid addition 1.6 g/L, and carbon-nitrogen ratio 23. Under the optimal condition, the content of total fatty acids could reach 47.16 g/100 g algal powder,which was 40.25％ higher than that of the control group. The fatty acid metabolic flux distribution in the cell of Schizochytrium sp. under different fermentation conditions showed that when the initial glucose content was 90 g/L, liquid loading volume was 60 ml/500 ml, carbon-nitrogen ratio was 8, the addition of citric acid and malic acid were 1.6 g/L, it was most beneficial to the synthesis of unsaturated fatty acid by acetyl-CoA (CoA) influx into the polyketide synthase (PKS) pathway. Under the condition, the ratio of unsaturated fatty acid to saturated fatty acid contents could reach 1.15,which was 21.28％higher than that of the control group.When carbon-nitrogen ratio was 14.75 and liquid loading volume was 220ml/500ml, the content ratio of docosahexaenoic acid (DHA) to docosapentaenoic acid (DPA) could reach 6.82, which was 3.02％ higher than that of the control group.%探究裂殖壶藻(Schizochytrium sp.)A3-9在不同发酵条件下生物量和脂肪酸含量的变化规律.结果显示,初始葡萄糖含量90 g/L,碳氮比8时最有利于裂殖壶藻生物量积累,此时生物量可达38.12 g/L,较对照组提高了104.59％;装液量220 mL/500 mL,柠檬酸添加量1.6 g/L,碳氮比23时总脂肪酸的积累可达47.16 g/100 g藻粉,较对照组提高了40.25％.不同发酵条件下裂殖壶藻胞内脂肪酸的代谢流量分布分析显示,初始葡萄糖含量90 g/L,碳氮比8,装液量60 mL/500 mL,柠檬酸和苹果酸添加量1.6 g/L时最有利于乙酰辅酶A(CoA)流入聚酮合酶(PKS)途径合成不饱和脂肪酸,此时不饱和脂肪酸与饱和脂肪酸含量之比可达1.15,相比对照组提高了21.28％;而当碳氮比14.75,装液量220mL/500mL时二十二碳六烯酸(DHA)与二十二碳五烯酸(DPA)含量之比可达6.82,较对照组提高了3.02％.
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