Exoproduction and characterization of a detergent-stable alkaline keratinase from Arthrobacter sp. KFS-1

Abstract

Arthrobacter sp. KFS-1 previously isolated from a dump site was used to produce keratinase in basal medium. The physico-chemical conditions were optimized to enhance the keratinase production, and biochemical properties of the enzyme were also evaluated. Arthrobacter sp. KFS-1 optimally produced keratinase in a basal medium that contained 1.0 g/L xylose, 2.5-5.0 g/L chicken feather; with initial pH, incubation temperature and agitation speed of 6.0, 30 °C and 200 rpm, respectively. Maximum keratinase activity of 1559.09 ± 29.57 U/mL was achieved at 96 h of fermentation; while optimal thiol concentration of 665.13 ± 38.73 μM was obtained at 144 h. Furthermore, the enzyme was optimally active at pH 8.0 and 60 °C. The enzyme activity was inhibited by ethylene diamine tetraacetic acid and 1,10-phenanthroline, but not affected by phenylmethylsulfonyl floride. In addition, the crude enzyme retained 55%, 63%, 80%, 81% and 90% of the original activity after respective pretreatment with some commercial detergents (Maq, Omo, Surf, Sunlight and Ariel). Moreso, the enzyme showed remarkable stability in the presence of reducing agents, surfactants, and organic solvents. Arthrobacter sp. KFS-1 significantly produced keratinase which exhibited excellent stability in presence of chemical agents and commercial laundry detergents; hence, suggesting its industrial application potentials especially in detergent formulation.

Keywords: Arthrobacter sp.; Chicken feather; Detergent formulation; Keratinase; Thiol group.