SALT-TOLERANT AND THERMOSTABLE ALKALINE PROTEASE FROM BACILLUS-SUBTILIS NCIM NO 64

The proteolytic activity produced by a Bacillus subtilis isolated from a hot spring was investigated. Maximum protease production was obtain ed after 38 h of fermentation. Effects of various carbon and nitrogen sources indicate the requirement of starch and bacteriological peptone to be the best inducers for maximum protease production. Requirement for phosphorus was very evident, and the protease was secreted over a wide range of pH 5-11. The partially purified enzyme was stable at 60- degrees-C for 30 min. Calcium ions were effective in stabilizing the e nzyme, especially at higher temperature. The enzyme was extremely salt tolerant and retained 100% activity in 5M NaCl over 96 h. The molecul ar weight of the purified enzymes as determined by SDS-PAGE was 28,000 . The enzyme was completely inactivated by PMSF, but little affected b y urea, sodium dodecyl sulfate, and sodium tripoly phosphate.