Abstract:To efficiently remove αs1-casein,the primary allergen in dairy products, a strain of Bacillus subtilis S7 with decent desensitization ability was screened from 3 000 strains of wild bacteria. High performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry(LC-MS/MS) were adopted to analyze the flavor of desensitization dairy products made by the key enzyme in Bacillus subtilis S7 and the bioactive peptides produced. By comparison with another candidate Bacillus subtilis S21, it was found that S7 had a higher activity to αs1-casein hydrolysis. To analyze this difference, all secreted enzymes were identified through peptide fingerprint. It was found that S7 could secrete and express more vegetative catalase. After the enzyme was recombinantly expressed and supplemented into the supernatant of Bacillus subtilis S21 fermentation broth, the activity of S21 to αs1-casein hydrolysis was increased by about 1.5 times to a level similar to that of S7. The enzyme activity to allergen was improved by vegetative catalase, which helped proteases to hydrolyze. The results show that desensitized milk products prepared by vegetative catalase and subtilisin E in Bacillus subtilis S7 may have promising application in the food industry.
