In order to improve the ability of Bacillus subtilis engineering bacteria to produce keratinase and reduce the cost of fermentation, the fermentation medium was optimized. First, the single-factor test was used to optimize the medium composition and culture conditions. And then, the Plackett-Burman test was designed, and three significant factors, yeast extract, pH and temperature, were obtained. Finally, the Box-Behnken center combination test was designed and the response surface analysis was performed. The optimized fermentation medium was 30 g/L sucrose, 40 g/L soybean meal, 5.72 g/L yeast extract, 3 g/L Na2HPO4·12H2O, 1.5 g/L KH2PO4, 0.3 g/L MgSO4·7H2O, and the optimized culture temperature was 37.69 ℃, with the inoculation amount 5%, and pH 7.68. Under the optimized condition, the enzyme activity in flask culture reached 260 480 U/mL at 24 h, which is 4.26 times higher than before. Furthermore, the keratinase activity reached 704 400 U/mL after 26 h of batch culture in a 3 L fermenter. In addition, the cost of the fermentation medium after optimization reduced to only 4% of the origin raw materials. In summary, the optimization of fermentation effectively improves the ability of Bacillus subtilis WB600 to produce keratinase, and greatly reduces the cost of fermentation, thus lays the foundation for the industrial production of keratinase.
MAO Xinzhe
,
PENG Zheng
,
ZHOU Guanyu
,
DU Guocheng
,
ZHANG Juan
. Optimized fermentation for improving keratinase production by Bacillus subtilis WB600[J]. Food and Fermentation Industries, 2020
, 46(17)
: 138
-144
.
DOI: 10.13995/j.cnki.11-1802/ts.023592
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