Bacterial Community Profiling during the Manufacturing Process of Traditional Soybean Paste by Pyrosequencing Method

• Published in: The Korean Journal of Microbiology Vol. 47; no. 3
• Main Authors: Kim, Y.S., Chonbuk National University, Jeonju, Republic of Korea, Jeong, D.Y., Sunchang Research Center for Fermentation Microbes (SRCM), Sunchang, Republic of Korea, Hwang, Y.T., Woorichon, Imsil, Republic of Korea, Uhm, T.B., Chonbuk National University, Jeonju, Republic of Korea
• Format: Journal Article
• Language: Korean
• Published: 01.09.2011
• Subjects: BACILLUS; BACTERIA; microbial community; pyrosequencing; soybean paste
• ISSN: 0440-2413

In order to evaluate the diversity and change of bacterial population during the manufacturing process of traditional soybean paste (doenjang), bacterial communities were analyzed using 16S rRNA gene-based pyrosequencing. In rice straw, the most important inoculum source for fermentation, the bacterial sequences with a relative abundance greater than 1% were assigned to four phyla, Proteobacteria (71%), Actinobacteria (20.6%), Bacteroidetes (4.2%), and Firmicutes (1.3%). Unlike bacterial community composition of rice straw, a different pattern of bacterial population in meju was observed with predominantly high abundance (99.1%) of Firmicutes. Phylum composition in young doenjang was almost same as that of meju. Major genera in young doenjang were Bacillus (81.3%), Clostridium (6.9%) and Enterococcus (6.3%) and the predominant species among bacterial population was B. amyloliquefaciens (63.6%). Abundance of the phylum Firmicutes in mature doenjang was 99.98%, which was even higher value than those in meju and young doenjang. Predominant species in mature doenjang were B. amyloliquefaciens (67.3%), B. atrophaeus (12.7%), B. methylotrophicus (6.5%), B. mojavensis (3.2%), and B. subtilis. (2.5%), which were also identified as major species of the microbial flora in meju. These results suggested that rice straw was a primary source for supplement of Bacillus species in manufacturing the traditional doenjang and that some species of Bacillus strains were mainly involved in the fermentation process of traditional doenjang.