Optimization of fermentation process of sugar- tolerant bread yeast

In order to optimize the sugar- tolerant bread yeast fermentation process,the conditions including fermentation temperature,rotation speed,liquid volume,initial p H,inoculation amount were optimized by experiment of single factor at first. Based on the experimental result,liquid volume,initial p H,inoculation amount were chosen to study on response surface optimization. The experimental results indicated that the optimum conditions were as follows: temperature at 30 ℃,rotation speed 200 r / min,8.4% liquid volume,p H4.7,7.4%inoculation amount.The condition increased dry weight of yeast by 55.72%. At the same time,by making growth curve to compare three methods including dissolved oxygen feedback feeding,constant feeding,intermittent feeding in 5.0 L mechanical stirring fermentation tank.It showed that the dissolved oxygen feedback feeding is best and the maximum wet yeast weight reached 143.95 g / L,the experiment reached the level of high density fermentation of sugar- tolerant bread yeast,and determine the optimal feeding mode of yeast.