Optimization of Low Yield Positive N-propyl Alcohol Fermentation Process of Bacillus cereus by Response Surface Methodology

Abstract

In order to optimize the separation of Luzhou flavor liquor Daqu and fermented grains in the low yield of n-propyl alcohol fermentation process of Bacillus cereus, single factor experiments were conducted to investigate the effects of four main factors, including fermentation time, inoculation amount of Bacillus cereus, fermentation temperature and initial pH of fermentation broth, on the content of n-propyl alcohol in fermentation broth. Then the response surface analysis and optimization were carried out with the response value of normal as the response value to establish a regression model for the fermentation process of Bacillus cereus. The results showed that the optimum fermentation time was 33 h, the inoculation amount of Bacillus cereus was 4.9%, the fermentation temperature was 32℃, and the initial pH of fermentation broth was pH7.0. Under the condition, the content of n-propyl alcohol in the fermentation broth was (0.70±0.0012) mg/100 mL, which had accordance with the predicted value of the model.