Chromohalobacter is a Causing Agent for the Production of Organic Acids and Putrescine during Fermentation of Ganjang, a Korean Traditional Soy Sauce

• Published in: Journal of food science 2015-12, Vol.80 (12), p.M2853-M2859
• Main Authors: Jung, Ji Young, Chun, Byung Hee, Jeon, Che Ok
• Format: Article
• Language: English
• Subjects: Acids; Acids - metabolism; Amino Acids - analysis; Bacillus; Bacillus - genetics; Bacteria; biogenic amines; Bioreactors; Carbon; Carbon compounds; Chromohalobacter; Chromohalobacter - genetics; Chromohalobacter - metabolism; doenjang-meju; Fatty Acids, Volatile - metabolism; Fermentation; Food Microbiology; ganjang fermentation; Glycine max - chemistry; Glycine max - microbiology; Humans; Metabolites; Microorganisms; Organic acids; putrescine; Putrescine - metabolism; RNA, Ribosomal, 16S - genetics; Sodium Chloride; Soy Foods - analysis; Soy Foods - microbiology; Soy sauce
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/1750-3841.13114

Ganjang, a Korean traditional fermented soy sauce, is prepared by soaking doenjang‐meju (fermented soybeans) in approximately 20% (w/v) solar salt solution. The metabolites and bacterial communities during ganjang fermentation were simultaneously investigated to gain a better understanding of the roles of the microbial population. The bacterial community analysis based on denaturing gradient gel electrophoresis of 16S rRNA gene sequences showed that initially, the genus Cobetia was predominant (0 to 10 d), followed by Bacillus (5 to 74 d), and eventually, Chromohalobacter became predominant until the end of the fermentation process (74 to 374 d). Metabolite analysis using 1H‐NMR showed that carbon compounds, such as fructose, galactose, glucose, and glycerol, probably released from doenjang‐meju, increased rapidly during the early fermentation period (0 to 42 d). After removal of doenjang‐meju from the ganjang solution (42 d), the initial carbon compounds remained nearly constant without the increase of fermentation products. At this point, Bacillus species, which probably originated from doenjang‐meju, were predominant, suggesting that Bacillus is not mainly responsible for ganjang fermentation. Fermentation products including acetate, lactate, α‐aminobutyrate, γ‐aminobutyrate, and putrescine increased quickly with the rapid decrease of the initial carbon compounds, while Chromohalobacter, probably derived from the solar salts, was predominant. Multivariate redundancy analysis indicated that the Chromohalobacter population was closely correlated with the production of the organic acids and putrescine during the ganjang fermentation. These results may suggest that Chromohalobacter is a causing agent responsible for the production of organic acids and putrescine during ganjang fermentation and that the solar salts, not doenjang‐meju, is an important microbial source for ganjang fermentation. Practical Application This study showed that Chromohalobacter was a causing agent responsible for the production of organic acids and putrescine during ganjang fermentation through the analysis of metabolites and bacterial communities. This study suggests that we may need to control the growth of Chromohalobacter during fermentation to produce good quality ganjang.