利用麸皮水解液培养深黄伞形霉积累油脂

Lipid accumulation by Umbelopsis isabellina from wheat bran hydrolysate

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2×106m L–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。

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 andγ-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.