Optimization of protease production by newly isolated Bacillus sp. from the Red Sea using defatted soybean cake

Abstract

Abstract In this study, three strains of alkaline protease-producing bacteria were isolated from marine seawater collected at a depth of 15 meters off the coast of Ras Sedr at Egypt’s Red Sea. The isolates were morphologically and biochemically characterized, and the most efficient strain was identified via 16S rRNA sequencing, showing 99% similarity to Bacillus amyloliquefaciens MPA 1034. Our newly isolated strain was deposited in the GenBank under the accession number PP034178.1 (Bacillus amyloliquefaciens NRC-IB-11). Six organic waste substrates, namely defatted almond cake, shrimp peel, wheat bran, chicken feathers, defatted flax cake, and defatted soybean cake, were evaluated for enzyme production, with defatted soybean cake yielding the highest activity. Under optimized conditions (10 g/100 mL of defatted soybean cake media, 10% v/v inoculum size, pH 10, 35 °C, and 160 rpm agitation speed), the newly isolated strain produced a maximum of 590 U/mL alkaline protease. This study introduces a novel marine-derived Bacillus strain with promising protease productivity and demonstrates sustainable bioprocessing, utilizing a single-component culture medium to minimize production costs.