Screening and characterization of protease from halophilic bacterium


Thidarat Juthong, M.Sc. Student in Biotech., PSU.
Wanna Choorit, Asst. Prof., Inst. of Agricultural Tech., Walailak U., Nakorn Si Thammarat
Poonsuk Prasertsan, Assoc. Prof., D. of Industrial Biotech., F. of Agro-Industry, PSU.
Prasert Suntinanalert, Assoc. Prof., D. of Microbiology, F. of Sci., PSU.
Corresponding e-mail : cwanna@wu.ac.th

Grant : Graduate School, PSU.
Presented : The 12th Annual Meeting of the Thai Society for Biotechnology "Biotechnology : Impacts & Trends", 1-3 November 2000, Kanchanaburi, Thailand
Key words : screening, characterization, protease, halophile, bacteria

An extremely halophilic bacterium, designed as SMl was isolated from traditional fermented fish (Pla-ra). Clear zone around the bacterium colony was observed after cultivation its at 37^oC in skim milk agar containing 25% NaCl for 4 days. The result showed that skim milk with 25% NaCl is a suitable media for enzyme production from the bacterium. The highest extracellularly proteolytic enzyme was produced after 7 days cultivation. The remaining activities of crude enzyme were 55.56% and 90.74% after storage an enzyme at 4^oC and -20^oC with 10% glycerol for 6 days, respectively. Stability of enzyme was pH range 7-8. Ultrafiltration and precipitation of enzyme with 95% ice ethanol will be performed.

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