Materials and Methods
Sampling and isolation. The fish used in top grade fish sauce
production in Thailand are Indo-Pacific Anchovies of the genus
Stolephorus (Pisces: Engraulidae). Samples collected from fish
fermentation tanks were plated on Trypticase Soy Agar (Difco
laboratories, Detroit Michigan) containing 1 % (wt/vol) casein
and 0, 10, 15, and 20% (wtlvol) sodium chloride. After incubation
for two days at 37 QC, protease producing colonies were selected,
i.e., colonies surrounded by a clear zone, indicating hydrolysis
of casein. Bacterial colonies showing strong proteolytic
activity on an high salt medium were isolated by repetitive
streaking and subjected to polyphasic taxonomic analysis.