Production and Physical Characterization of Thermo-stable and Organic Solvents-tolerant Protease from Mesophilic Bacillus sp. NASK P6

Naif Abdullah Al-Harbi

Department of Botany and Microbiology, Addiriyah Chair for Environmental Studies College of Science, King Saud University, B.O. Box 2455 Riyadh 11451, Saudi Arabia.

Corresponding Author E-mail: naalharbi@ksu.edu.sa

ABSTRACT: Production of protease enzyme from soil newly isolated Bacillus sp. (NASK P6) was investigated. The proteolytic activity was observed when the bacteria were grown in the minimal medium containing sucrose, K2HPO4, MgSO4, KCl2 and FeSO4 in shake flask culture condition. 16S rRNA phylogenetic analysis revealed that isolate NASK-P6 closely related to B. subtilis. Different inoculums size such as 1, 2, 3, 4, 5 and 10% in the same medium and further selected inoculums size with various carbon and nitrogen sources were used for production. The protease productivity was determined with various time interval i.e., 24, 48 and 72 hrs with 100 ml medium. The maximal productivity obtained (6319 U ml-1) in the 1% inoculums size at 72 hours, will be used to select best carbon, nitrogen and raw waste substrates. The maximum enzyme yield obtained in glucose (10564 U/ml/72 hrs), yeast extract (13777 U ml-1) and dhore dhal washing (19760 U ml-1) as most selective carbon, nitrogen and raw waste substrates respectively. Further the crude enzyme was subjected to various physical factors like temperature, pH and solvent stability analysed. The enzyme was highly active in alkaline pH (9.0), high temperature (55o C) and also active in acetone exposure.

KEYWORDS: Proteases; Bacillus; Thermo stable; Enzyme

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