Abstract:

The aim of this study was to increase the amount of Zygosaccharomyces rouxii and break the bottleneck of long fermentation time in the industrialized production of soy sauce. On the basis of single factor experiment, response surface methodology was used to optimize the composition of the medium. 3 significant factors were quickly and effectively screened out of 9 factors affecting the amount of Zygosaccharomyces rouxii by Plackett-Burman design: glucose, soybean meal, manganese sulfate. The maximum response interval was obtained by the steepest climb test and the optimal medium combination was obtained by Box-Behnken design. The optimal medium combination was as follows: glucose 58 g/L, corn meal 20 g/L, phosphate dibasic Ammonium hydrogen 5 g/L, soybean meal 43 g/L, potassium dihydrogen phosphate 1 g/L, disodium hydrogen phosphate 2 g/L, zinc sulfate 0.04 g/L, manganese sulfate 0.04 g/L, magnesium sulfate 0.5 g/L. Under the optimal medium combination, the amount of Zygosaccharomyces rouxii reached 12.81×10⁸ cfu/mL, which was 3.64 times higher than that before optimization.

Key words: Zygosaccharomyces rouxii, soy sauce production, single factor experiment, response surface experiment, medium optimization