Optimization of Culture Conditions to Produce Thermostable Keratinolytic Protease of Brevibacillus thermoruber LII, Isolated from the Padang Cermin Hot Spring, Lampung, Indonesia

Proteases have numerous biotechnological applications and the bioprospection for newly-thermostable proteases from the great biodiversity of thermophilic microorganisms inhabiting hot environments, such as geothermal sources, aims to discover more effective enzymes for processes at higher temperatures. We report in this paper the production and the characterization of a purified acid protease from strain OA30, a moderate thermophilic bacterium isolated from an Algerian hot spring. Phenotypic and genotypic study of strain OA30 was followed by the production of the extracellular protease in a physiologically-optimized medium. Strain OA30 showed multiple extracellular proteolytic enzymes and protease 32-F38 was purified by chromatographic methods and its biochemical characteristics were studied. Strain OA30 was affiliated with Brevibacillus thermoruber species. Protease 32-F38 had an estimated molecular weight of 64.6 kDa and was optimally active at 50 °C. It showed a great thermostability after 240 min and its optimum pH was 6.0. Protease 32-F38 was highly stable in the presence of different detergents and solvents and was inhibited by metalloprotease inhibitors. The results of this work suggest that protease 32-F38 might have interesting biotechnological applications.

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“…Monomeric proteases with molecular weights between 60 and 66 kDa from Brevibacillus sp. have been reported in literature [ 45 , 46 , 47 ].…”

Section: Resultsmentioning

confidence: 99%

“…Weak activities were still observed at pH 5.0 and 11.0. The majority of extracellular proteases reported in literature from Brevibacillus members were alkaline proteases with optimal pH around 8.0 [ 46 , 47 , 50 , 51 ], and acid proteases were rarely reported [ 45 ].…”

Section: Resultsmentioning

confidence: 99%