In order to inhibit the growth of pathogens and degrade biogenic amines during the fermentation of soybean
products, an isolate with antimicrobial activity against pathogens and biogenic amine-degrading property was
obtained from 83 traditionally fermented soybean products. The morphological and biochemical tests and the
phylogenetic relationship among 16S rRNA gene sequences indicated that the isolate named as the strain SCK B11
was most closely related to Bacillus licheniformis. The cell-free supernatant of two day cultures was active against
several pathogens including Enterococcus faecalis, Listeria monocytosis, Micrococcus luteus, Pseudomonas
aeruginosa, Bacillus cereus, and Staphylococcus aureus. PCR analysis was conducted to determine relatedness to
antimicrobial lantibiotics and biosurfactants produced by Bacillus spp., but showed negative for the genes encoding
surfactin, lichenysin, and lichenicidine. Electron microscopic observation indicated that the antimicrobial agent
seemed to attack the membrane of the pathogens, leaving the ghost or shrunken cells. The strain was found to
degrade histamine by 72% and tyramine by 66% in the cooked soybean containing 5.3% of biogenic amine over 10
days of fermentation time. The use of selected strain would be a potential control measure in manufacturing
traditionally fermented soybean products that are difficult to control pathogens and biogenic amine levels.
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