Monitoring of changes in lactic acid bacteria during production of Thai traditional fermented shrimp (Kung-Som) by culturing method and PCR-DGGE technique

Abstract

The lactic acid bacteria (LAB) ecology of Kung-Som, a traditional Thai fermented shrimp, was investigated using culture-dependent and culture-independent methods. Kung-Som was fermented at room temperature under anaerobic condition for 7 days using autochthonous fermentation. The viable counts revealed a dominance of LAB, from the 16S rRNA gene V6-V8 sequence analysis of the isolates, Enterococcus faecalis, Enterococcus sanguinicola, Weissella cibaria, Weissella confusa, Enterococcus sp., Leuconostoc pseudomesenteroides and Lactobacillus plantarum were observed. The total microbial community was profiled without cultivation by analyzing the DNA that was directly extracted from the Kung-Som samples. The 16S rRNA gene V6-V8 regions were used as targets in the denaturing gradient gel electrophoresis (DGGE), profiling of the LAB. Pediococcus argentinicus, Lactococcus lactis subsp. lactis, Lactococcus garvieae, Lactobacillus curvatus, Lactobacillus sakei and Lact. plantarum were observed. Our results provide evidence of the necessity to combine the two methods for better description of microbial communities in Kung-Som fermentation.

Keywords

• culture-dependent method
• culture-independent method
• 16S rRNA gene
• PCR-DGGE