Bacterial Community Migration in the Ripening of Doenjang, a Traditional Korean Fermented Soybean Food

Abstract

Doenjang, a traditional Korean fermented soybean paste, is made by mixing and ripening meju with high salt brine (approximately 18%). Meju is a naturally fermented soybean block prepared by soaking, steaming, and molding soybean. To understand living bacterial community migration and the roles of bacteria in the manufacturing process of doenjang, the diversity of culturable bacteria in meju and doenjang was examined using media supplemented with NaCl, and some physiological activities of predominant isolates were determined. Bacilli were the major bacteria involved throughout the entire manufacturing process from meju to doenjang; some of these bacteria might be present as spores during the doenjang ripening process. Bacillus siamensis was the most populous species of the genus, and Bacillus licheniformis exhibited sufficient salt tolerance to maintain its growth during doenjang ripening. Enterococcus faecalis and Enterococcus faecium, the major lactic acid bacteria (LAB) identified in this study, did not continue to grow under high NaCl conditions in doenjang. Enterococci and certain species of coagulase-negative staphylococci (CNS) were the predominant acid-producing bacteria in meju fermentation, whereas Tetragenococcus halophilus and CNS were the major acid-producing bacteria in doenjang fermentation. We conclude that bacilli, LAB, and CNS may be the major bacterial groups involved in meju fermentation and that these bacterial communities undergo a shift toward salt-tolerant bacilli, CNS, and T. halophilus during the doenjang fermentation process.

Metaproteomics of Microbiota in Naturally Fermented Soybean Paste, Da‐jiang

“…Jeong et al. () found that Enterococcus faecalis and Enterococcus faecium were the predominant Enterococcus in meju samples. As enterococci are an essential part of the microflora of humans and animals, we can speculate that Enterococcus faecalis in da‐jiang comes from humans during the process of mashing and molding the steamed soybean (Jeong, Jeong, & Lee, ).…”

Complete Genome Sequence of Staphylococcus succinus 14BME20 Isolated from a Traditional Korean Fermented Soybean Food

“…In our previous analysis of the cultivable bacterial community during the ripening of doenjang, a traditional fermented soybean food, coagulase-negative staphylococci (CNS) species, including Staphylococcus succinus , were isolated as a dominant bacterial group (1). In our successive study to select potential CNS starters for Korean fermented soybean foods, S. succinus isolates were identified as promising candidates in terms of safety, as well as technological functionality (2).…”

Influence of bacterial starter cultures on the sensory characteristics of doenjang, a fermented soybean paste, and their impact on consumer hedonic perception

“…Lactic acid bacteria including enterococci and coagulase‐negative staphylococci (CNS) have been identified as the predominant group of bacteria together with bacilli. We analyzed the microbiota of meju and doenjang using culture‐dependent methods and isolated numbers of bacilli, enterococci, and CNS (Jeong et al, ). In the following assessments of the safety, proteolytic and lipolytic enzyme activities, and salt tolerance of isolates, followed by analyses of the volatile compounds produced from their soybean cultures (Jeong, Heo, et al, ; Jeong, Jeong, & Lee, ; Jeong, Jeong, et al, ; Jeong, Lee, Her, Lee, & Lee, ), three strains of Bacillus licheniformis , Enterococcus faecium , and Staphylococcus succinus have been selected.…”