Changes in Microbial Community Composition during Production of Takanazuke

Abstract

Changes in microbial community composition of takana produced by a conventional fermenatation method with 6% (w/w) NaCl were analyzed. Harvested takana leaves were pickled with 6% (w/w) NaCl in Aso city, transported to our laboratory in Kumamoto city, and then incubated at the average monthly temperatures of the Aso area. The lactate concentration and D- to L-lactate ratio increased during the 180-day fermentation. Partial sequencing of the 16S rRNA gene was used to determine the microbial composition of takanazuke on days 0, 19, 40, 90, and 180. Only Pseudomonas was detected on day 0, whereas Lactobacillus curvatus was clearly the dominant species on day 19. After 40 days, L. curvatus (56.9%), L. (para)plantarum (39.2%), and L. sakei (3.9%) were detected, whereas on day 90, the bacterial population consisted of L. (para)plantarum (50.9%), L. sakei (45.6%), L. curvatus (1.7%), and members of the genus Weissella (1.7%). The final microbial composition on day 180 of the fermentation was L. (para) plantarum (59.6%), genus Weissella (32.7%), L. curvatus (3.8%), L. alimentarius (1.9%), and genus Clostridium (1.9%).