EFFICIENT PROTEOLYSIS AND APPLICATION OF AN ALKALINE PROTEASE FROM HALOPHILIC Bacillus sp. EMB9

Abstract

A salt-stable alkaline protease from moderately halophilic Bacillus sp. EMB9, isolated from the western coast of India, is described. This protease was capable of efficiently removing silver from used/waste X-Ray films, as well as hydrolyzing defatted soy flour with 31% degree of hydrolysis (DH). Production of the protease was optimized by using response surface methodology. Ca²⁺ and NaCl were the most critical factors in enhancing the yield. Under optimized culture conditions, a maximum of 369 U protease/mL was obtained, which is quite comparable to the yields of commercial proteases. The elevated production level coupled with ability to efficiently hydrolyze protein-laden soy flour and complete recovery of silver from used X-Ray films makes it a prospective industrial enzyme.

Keywords:

• Bacillus sp.
• halophilic
• hydrolysates
• protease
• RSM
• soy flour

Notes

Note. R ² = 0.9156, , CV = 20.58, adequate precision ratio = 13.403.

Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/lpbb.