Functional analysis of bacteria isolated from soy sauce moromi

Abstract:

[Objective] To isolate and characterize bacteria from soy sauce moromi and evaluate their potential applications in soy sauce production. [Methods] The dominant or specific bacterial strains will be isolated from Japanese-style soy sauce moromi. And their capabilities in salt tolerance, proteinase secretion and production of organic acid, amino acids, volatile compounds under high salt condition will be assessed. [Results] A total of nine strains belonging to the genus of Weissella, Pediococcus, Lactobacillus, Bacillus, Tetragenococcus and Staphylococcus were isolated from soy sauce moromi. Weissella paramesenteroides CQ03, Pediococcus acidilactici JY07, Pediococcus pentosaceus JY08, Staphylococcus sp. JY09 and Tetragenococcus halophilus MRS1 were found to be salt-tolerant strains. Bacillus amyloliquefaciens B2 exhibited stronger capability in secretion of protease and glucoamylase. W. paramesenteroides CQ03 produced more umami tasting amino acids than other isolates. Both T. halophilus MRS1 and S. sp. JY09 retained high activities in synthesis and accumulation of volatile compounds. The potential capability in organic acids production by T. halophilus MRS1 was also detected. [Conclusion] Nine strains that belong to different species with potential capability in promoting raw materials hydrolysis and improving soy sauce aroma were obtained. The results demonstrated their benefit for shortening fermentation duration and improving the quality of soy sauce.