玉米酒糟离心上清液发酵产单细胞蛋白的工艺优化

Process optimization of single cell protein production through fermentation of upper serum of centrifugalized corn distiller's grains

利用中心组合响应面法优化了以玉米酒糟离心上清液为原料、产朊假丝酵母为菌种发酵生产单细胞蛋白的工艺。首先通过单因素优化法优化了培养条件,采用Plackett-Burman(PB)设计试验筛选出影响发酵效果的显著性因素,再通过响应面优化试验确定最优条件。试验结果表明,采用廉价易得的碳氮源玉米糖化醪及尿素,最优培养基组成为糖化醪体积分数为17%,ρ(尿素)=0.8 g/L;在最优条件下开展了3.7 L发酵罐流加发酵试验,发酵液中粗蛋白干基质量分数达到29.4%,较发酵前提高38.0%。

CCD-RSM（central composite design-response surface methodology） design is applied to optimize the production process for single cell protein by using upper serum of centrifugalized corn distiller＇s grains as raw material and Candida utilis as strain.Firstly,the cultural conditions are optimized by single factor optimization method.Secondly,the significant factors that affect fermentation effect are screened by Plackett-Burman design test.Finally,the optimal conditions are determined through CCD-RSM design test.The result suggests that the optimum culture matrix composes17% volume fraction of saccharification liquor and 0.8 g·L-1 of urea when cheap and available saccharification liquor and urea are used as the source of carbon and nitrogen,respectively.Under the optimal conditions,fed-batch fermentation experiment is conducted in a 3.7 L fermenting tank.The result reveals that the mass fraction of crude protein in fermentation liquid reaches 29.4%,an increase of 38.0% comparing with that before fermentation.