title: Statistical optimization of culture conditions for milk-clotting enzyme production by bacillus amyloliquefaciens using wheat bran-an agro-industry waste.
abstract: In order to improve the production of the milk-clotting enzyme under submerged fermentation, two statistical methods were applied to optimize the culture conditions of Bacillus amyloliquefaciens D4 using wheat bran as nutrient source. First, initial pH, agitation speed, and fermentation time were shown to have significant effects on D4 enzyme production using the Plackett-Burman experimental design. Subsequently, optimal conditions were obtained using the Box-Behnken method, which were as follows: initial pH 7.57, agitation speed 241 rpm, fermentation time 53.3 h. Under these conditions, the milk-clotting enzyme production was remarkably enhanced. The milk-clotting enzyme activity reached 1996.9 SU/mL, which was 2.92-fold higher than that of the initial culture conditions, showing that the Plackett-Burman design and Box-Behnken response surface method are effective to optimize culture conditions. The research can provide a reference for full utilization of wheat bran and the production of milk-clotting enzyme by B. amyloliquefaciens D4 under submerged fermentation.
authors.affiliation: College of Food Science and Technology Engineering, Gansu Agricultural University, Lanzhou, 730070 China.
authors.forename: Weibing
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Dingxi Center for Disease Control and Prevention, Dingxi, 74300 China.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: He
authors.affiliation: College of Food Science and Technology Engineering, Gansu Agricultural University, Lanzhou, 730070 China.
authors.forename: Hongna
authors.initials: H
authors.lastname: Liu
authors.affiliation: Key Laboratory of Functional Dairy, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083 China.
authors.forename: Huiyuan
authors.initials: H
authors.lastname: Guo
authors.affiliation: College of Food Science and Technology Engineering, Gansu Agricultural University, Lanzhou, 730070 China ; Key Laboratory of Functional Dairy, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083 China.
authors.forename: Fazheng
authors.initials: F
authors.lastname: Ren
authors.affiliation: College of Food Science and Technology Engineering, Gansu Agricultural University, Lanzhou, 730070 China.
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Wen
keywords: Culture Conditions; Milk-clotting enzyme; Optimization; Wheat bran