马铃薯淀粉水解条件优化及油脂酵母培养研究

以马铃薯淀粉为底物，葡萄糖含量为评价指标，通过响应面法优化淀粉酶解工艺，将水解液用于发酵生产微生物油脂。最佳酶解条件为马铃薯淀粉质量浓度20 mg/mL，加酶量为干淀粉质量3.2%，α-淀粉酶、葡萄糖淀粉酶的质量比2.2∶1，pH 4.1，酶解时间4.1 h，得到最高葡萄糖含量为15.06 mg/mL。向此水解液中添加一定氮源和无机盐用于油脂酵母菌株Y004-2培养，在250 mL三角瓶中其生物量为14.43 g/L，油脂产量5.16 g/L，在5.0 L发酵罐中生物量为14.27 g/L，油脂产量5.10 g/L，其生物量和油脂产量均略高于以葡萄糖为碳源；且菌株Y004-2在以马铃薯淀粉水解液为碳源的培养基中所得油脂的组成与以葡萄糖为碳源的培养基中所得油脂的脂肪酸组成相同。

Optimization of potato starch hydrolysis conditions and cultivation of oleaginous yeast

Using potato starch as substance, glucose yield as evaluation index, the optimum hydrolysis conditions was optimized by response surface methodology, and then the hydrolysate was used for microbial oil production. The results showed that the optimum hydrolysis condition was starch concentration 20 mg/ml, enzyme addition 3.2% of dry starch, α-amylase to glucamylase mass ratio 2.2∶1, pH 4.1, and hydrolysis time 4.1 h. Under the condition, the glucose content reached 15.06 mg/ml. Nitrogen source and inorganic salt was added in the hydrolysate to culture oleaginous yeast Y004-2, the biomass was 14.43 g/L, oil production was 5.16 g/L in 250 ml flask. While the biomass was 14.27 g/L, oil production was 5.10 g/L in 5.0 L fermenter. The oil composition of strain Y004-2 in the medium of potato starch hydrolysate as carbon source was same with glucose as carbon source.