Screening and optimization of candidate alkaline protease for dehairing potential from marine Bacillus paramycoides M2

Abstract

Alkaline proteases are active from neutral to alkaline pH range and have extensive applications in detergent and leather industries. In the present research, bacteria isolated from marine water samples were screened for proteolytic activity. Among the isolates, M2 showed maximum proteolysis with a clear zone when cultured on skim milk agar plates at 37°C for 24 h. Molecular identification using 16S rRNA sequencing and phylogenetic analysis revealed that M2 has sequence identity (99.93%) to Bacillus paramycoides. SEM analysis was carried for determining the morphology of M2 and also for enzyme treated skin. FAME analysis using GCMS was performed for the determination of fatty acids in the strain. The selected isolate was inoculated into protease production medium under submerged fermentation conditions at 37ºC for 48 h with a constant agitation of 120 rpm. Protease activity was determined under varying conditions of pH, incubation temperature, carbon and nitrogen sources, metal ions and NaCl (1- 5%) using casein as substrate. The isolate M2 utilized molasses and peptone as carbon and nitrogen sources for better alkaline protease production at 40°C and pH 10 under optimal conditions. The dehairing experiments with M2 alkaline protease revealed dehairing efficacy of protease over chemical treatment. Hence, extracellular alkaline protease from M2 isolate could find potential application in leather processing industries and can be exploited commercially.