Optimization of production of an oxidant and detergent-stable alkaline β-keratinase from Brevibacillus sp. strain AS-S10-II: Application of enzyme in laundry detergent formulations and in leather industry

Present study is the first report on production and purification of β-keratinase enzyme from a bacterium belongs to the genus Brevibacillus. The response surface optimized alkaline β-keratinase production by this strain was achieved as 923.0 × 103 U l−1 post 48 h of incubation. An alkaline β-keratinase (Brevicarnase) having molecular mass of 83.2 kDa purified from this strain showed optimum activity at 45 °C and pH 12.5, respectively. The Km and Vmax values of β-keratinase towards keratin were determined as 0.3 mg ml−1 and 4.5 μmol min−1 mg−1, respectively. The Brevicarnase demonstrated appreciable thermo-stability and stability in the presence of anionic and non-ionic surfactants, oxidizing and bleaching agents, EDTA, and compatibility with the tested commercial laundry detergents at a concentration of 0.1%. The purified β-keratinase did not show collagen-degrading activity however, demonstrated dehairing property when tested on goat skin. These properties reinforce the feasibility of inclusion of Brevicarnase in laundry detergent formulations and in leather-industry.

Research highlights
► This is first report on statistical optimization of β-keratinase enzyme production and purification from Brevibacillus sp. AS-S10-II strain.
► An alkaline β-keratinase (Brevicarnase) with molecular mass of 83.2 kDa displayed optimum activity at 45 °C and pH 12.5.
► Brevicarnase demonstrated application oriented properties such as excellent thermostability, compatibility with commercial laundry detergents at a concentration of 0.1% (v/v) and dehairing activity suggesting its inclusion in commercial laundry detergent formulations and in leather- industry as eco-friendly dehairing agent.