Characterization of Alkaline Phosphatase Producing Bacteria Isolated from Thai Fermented Fish Products

Seventeen isolates of alkaline phosphatase (ALP) producing bacteria were screened and systematically studied. They were divided into 10 groups on the basis of their phenotypic characteristics and 16S rRNA gene sequence analyses. The Gram-positive coccal isolates in Group I (3 isolates), Group II (3 isolates) and Group III (1 isolate) showed 99.2%, 99.5-99.7% and 99.8% sequences similarity to Staphylococcus saprophyticus, S. napalensis and S. sciuri, respectively. Each Gram-positive rod-shaped isolates in Group IV and V belonged to the genus Bacillus and was closely related to B. vietnamensis and B. safensis with 99.2% and 99.4% sequences similarity, respectively. The Gram-positive, moderately halophilic rod-shaped bacteria in Group VI (3 isolates), Group VII (1 isolate), Group VIII (1 isolate) and Group IX (2 isolates) were closely related to Virgibacillus halodenitrificans (98.5-99.1%), Oceanobacillus iheyensis (99.3%), Halobacillus mangrove (97.9%) and H. dabanensis (98.5-98.6%), respectively. One Gram-negative isolate of moderately halophilic bacterium (Group X) was closely related to Idiomarina zobelli (98.0%). They possessed phosphatase activities ranged from 10.08-70.96 U ml-1. The isolate NSW 13-2 (Group VI) showed the highest ALP.