ISOLATION OF HALOPHILIC LACTIC BACTERIA TETRAGENOCOCCUS HALOPHILUS FROM VIETNAMESE FISH SAUCE

Abstract

Halophilic lactic bacteria Tetragenococcus halophilus were isolated from Thailand fish sauce. They were suggested to play an important role in flavor and aroma development and used as starter culture during fish sauce fermentation.In this study the isolation of Tetragenococcus halophilus from two different factories of fish sauce production in Vietnam was conducted on MRS agar media supplemented with 0.5 % CaCO3 and 5 % NaCl under anaerobic condition. The Tetragenococcus halophilus was present in all investigated fish sauce samples from 2 months to 8 months. Six isolates CH2-4, CCH8-3, CH6-1, CH6-2, CH8-1 and V5-1 were selected based on various ability to grow in fish broth supplemented with 25 % NaCl and degrade fish protein to oligopeptide. The 16S rDNA sequence analysis of 6 isolates showed that they were closely related to Tetragenococcus halophilus ATCC 33315 and Tetragenococcus halophilus MCR10-7-8 and MRC 5-5-2 from study of Thailand scientist with more than 99 % sequence homology, suggesting their potential using as starter culture in fish sauce fermentation.