Optimization of fermentation conditions of oleaginous yeast Lipomyces starkeyi for fatty produce | 斯达氏油脂酵母高产油发酵培养条件的优化

صينى. 通过摇瓶发酵，对斯达氏油脂酵母的产油发酵条件进行优化。利用单因素试验，确定最佳碳源、氮源、初始pH值、无机盐的质量浓度；利用4因素3水平正交试验，优化碳源质量浓度、氮源质量浓度、接种量、培养温度等参数；同时考察发酵时间对斯达氏油脂酵母生长及油脂产量的影响。单因素试验结果表明，以葡萄糖为碳源时，斯达氏油脂酵母发酵生物量及油脂产量明显高于其他碳源；以(NH4)2SO4为氮源时，则生物量、油脂产量均最高；最佳初始pH值为6.0～6.5；无机盐离子的最适添加质量浓度为：MgSO4•7H2O 1.5 g/L，KH2PO4 3.0 g/L。碳源质量浓度、氮源质量浓度、接种量、培养温度4因素3水平正交试验的极差分析结果表明，培养温度对斯达氏油脂酵母的生物量和油脂产量的影响最大。斯达氏油脂酵母发酵培养基的最优组合为:葡萄糖90 g/L，(NH4)2SO4 3.5 g/L，接种量10%，培养温度28 ℃。在摇瓶发酵过程中，发酵培养144 h时菌体生物量、油脂产量均最高， OD600值也较高。在优化条件下对斯达氏油脂酵母进行摇瓶发酵，获得的菌体生物量最高可达16.35 g/L，较优化前提高了25.19%；油脂产量为4.94 g/L，较优化前提高了97.84%；菌体含油率最高可达302.1 g/kg。

إنجليزي. Single factor experiments and orthogonal design experiments were carried out to optimize fermentation conditions of oleaginous yeast Lipomyces starkeyi for fatty produce. In shaking-flask means of incubation, the fermentation of L. starkeyi was tested in different culture condition optimization by single factor experiment and orthogonal design of carbon source, nitrogen source, seed inoculum rate and temperature. The results showed that mass yield and fatty rate were obviously higher by glucose than by other carbon source; also the mass yield was the highest when (NH4)2SO4 was used as nitrogen sources; meanwhile optimal initial pH was at 6.0－6.5, MgSO4•7H2O 1.5 g/L, KH2PO4 3.0 g/L. Throughout the orthogonal experiments of glucose, (NH4)2SO4, seed inoculum rate and temperature, the optimal culture condition was found as follows: glucose 90 g/L, (NH4)2SO4 3.5 g/L, seed inoculum rate about 10%, the incubating temperature equals 28 ℃. According to OD600 of cultured liquid, the incubating time was 144 h when mass yield grew up to the maximum. Under the optimum culture condition, the biomass yield was 16.35 g/L, 25.19% higher than that with unoptimized condition, while the lipid content was 4.94 g/L, 97.84% higher against unoptimization, and the highest lipidic content was 302.1 g/kg of the biomass.