Identification of Halophilic Bacteria from Fish Sauce (nam-pla) in Thailand

Four strains of Gram-negative, rod-shaped, moderately halophilic bacteria, Group A, and eleven strains of strictly aerobic, extremely halophilic rods (10 strains, Group B) and coccoid (1 strain, Group C) were isolated from fish sauce fermentation (nam-pla) in Thailand. The 16S rRNA gene sequence analyses of the representative strains indicated that DS26-2 (Group A), HDS2-5 (Group B), and HRF6 (Group C), were closely related to Chromohalobacter salexigens KCTC 12941, Halobacteirum salinarum JCM 8978, and Halococcus saccharolyticus JCM 8878 with 99.3, 99.9, and 99.0 % similarity, respectively. Group A strains were identified as C. salexigens, Group B as H. salinarum, and Group C strain was H. saccharolyticus based on their DNA-DNA relatedness. Group A strains grew in 3–25 % (w/v) NaCl. Ubiquinone with nine isoprene units (Q-9) was a major component. The DNA G+C contents ranged from 63.1 to 64.2 mol %. Group B and Group C strains grew optimally in the presence of 25-30 % NaCl. The tested strains of Group B contained major menaquinone with eight isoprene units (MK-8). DNA G+C contents ranged from 63.3 to 64.7 mol %. Group C strain had MK-8(H2) as a predominant menaquinone. The DNA G+C content was 63.2 mol %.