Abstract: To investigate the lipid accumulation by Umbelopsis isabellina from the wheat bran hydrolysate, the effects of temperature, pH and inoculum size were investigated through one factor at a time experiments. After that, the lipid accumulation was optimized using the response surface methodology. A correlation was developed after three factors, three level experiments designed by Box-Behmken software. The highest lipid yield was obtained at the conditions of 27℃, pH 4.6, and 2×10⁶mL^-1 inoculum size. It was found that Umbelopsis isabellina accumulated 9.81g/L lipid with 24.93g/L dry biomass after 5d cultivation. The lipid content was 39.35%. It was showed that Umbelopsis isabellina utilized 69.40% total sugar including the mannose, glucose, xylose, arabinose, and some of polysaccharides. Residual polysaccharides contributed 84.30% residual total sugar according to the HPLC analysis. The lipid from Umbelopsis isabellina had 67.70% unsaturated fatty acid, and 18.11% polyunsaturated fatty acid including the linoleic acid and γ-linolenic acid mainly. Therefore, the lipid production through oleaginous fungal species Umbelopsis isabellina from hydrolysate of wheat bran was built, which provided an option for the wheat bran utilization.

Key words: wheat bran hydrolysate, Umbelopsis isabellina, lipid, response surface methodology, polyunsaturated fatty acid

摘要： 为了探讨利用麸皮水解液培养深黄伞形霉积累油脂情况，首先通过单因素实验研究了培养温度、pH和接种量对油脂产量的影响，进而通过响应面方法优化培养条件。采用Box-Behnken设计建立了3因素3水平响应面和回归模型。油脂产量最高的条件为培养温度27℃、最适pH 4.6，接种量2×10⁶mL^-1。经过5天发酵后，油脂产量达到最高值（9.81g/L），菌体产量为24.93g/L，菌体中油脂含量（质量分数）为39.35%。通过高效液相色谱测定了水解液中残糖种类的变化，发现总糖利用率为69.40%，深黄伞形霉能够利用甘露糖、葡萄糖、木糖、阿拉伯糖以及部分多聚糖。残余糖中84.3%为多聚糖。气相色谱质谱联用仪分析发现油脂中不饱和脂肪酸含量（质量分数）为67.70%，多不饱和脂肪酸的含量（质量分数）为18.11%。多不饱和脂肪酸主要为亚油酸和γ-亚麻酸。本研究建立了由深黄伞形霉利用麸皮水解液积累油脂的途径，为综合利用麸皮提供了一个选择。

关键词: 麸皮水解液, 深黄伞形霉, 油脂, 响应面优化, 多不饱和脂肪酸