Characterization of thermostable serine protease from <i>Bacillus</i> <i><span style="font-size:15.0pt;font-family:"Times New Roman";mso-fareast-font-family: "Times New Roman";mso-ansi-language:EN-IN;mso-fareast-language:EN-IN; mso-bidi-language:AR-SA">altitudinis </span></i><span style="font-size:15.0pt; font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language:AR-SA">strain BR1</span>

Abstract

This study is carried out for partially purified and characterized thermostable serine protease from alkaliphilic estuarine bacterium <i>Bacillus altitudinis </i>strain BR1 from Goa, India. The extracellular protease was stable at 50^o C and alkaline pH 9-11. Protease activity was maximum at pH 9 and 50^o C confirming it to be a thermostable, alkaline protease. Interestingly this bacterial strain possessed 5 distinct alkaline protease isozymes with approximate molecular mass of 17, 22, 43, 64 and 88 kDa which was clearly revealed by Zymogram. These isozymes are possibly encoded by five different genes. Phenyl methyl sulfonyl fluoride (PMSF) significantly inhibited protease suggesting it to be a serine protease. Interestingly protease production remained unaltered

in presence of EDTA-Na₂ and <span style="font-size:9.0pt;font-family: Symbol;mso-bidi-font-family:Symbol">b-mercaptoethanol. Significant morphological change as cell size reduction and transformation of rod shaped cells to oval cells at 50^o C without any adverse effect on protease activity may prove a protective mechanism to temperature stress. These results clearly demonstrated stability and activity of these serine protease isozymes at high temperature and alkalinity which is advantageous for various industrial applications.

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