Biodegradation of a keratin waste and the concomitant production of detergent stable serine proteases from Paecilomyces lilacinus

CAVELLO, IA; CAVALITTO,S.F; HOURS, RA

Trivandrum

Congreso; International Conference on New Horizons in Biotechnology and 8 th Annual Convention of The Biotech Research Society, India.; 2011

National Institute for Interdiciplinary Science and Technology, CSIR, Trivandrum. The Biotech Research Society, India.

Paecilomyces lilacinus strain LPS # 876, isolated from alkaline soils from Buenos Aires Province (Argentine), efficiently degraded feather keratin during submerged cultivations, producing extracellular proteases. The present study describes the characterization of crude protease and its compatibility in commercial detergents. The optimum pH and temperature for proteolytic activity were 10.0 and 60°C, respectively. Protease activity was enhanced in the presence of 1 mM Ca2+ and Mg2+, but was strongly inhibited by PMSF and by Hg2+ suggesting the presence of thiol-dependent serine proteases. The crude protease showed extreme stability toward non-ionic (5% Tween 20; 5% Tween 85 and 5% Triton X-100) and anionic (1% SDS) surfactants, and relative stability toward various oxidizing agents. In addition, it showed excellent stability and compatibility with different solid (7 mg/ml) and liquid (1% v/v) commercial detergents for 1 h at temperatures from 30 to 50°C. The enzyme preparation retained more than 95% of its initial activity after pre-incubation at 40°C with solid detergents (Ariel™ and Drive™ followed by Skip™ and Ala™). It retained 97% of its original activity after pre-incubation at 40°C with a liquid detergent (Ace™). The protective effect of polyols (propylene glycol, PEG 4000 and glycerol) on the heat inactivation was also examined and the best results were obtained with glycerol from 50 to 60°C. Considering its promising properties, P. lilacinus enzymatic preparation may be considered a potential candidate for future use in biotechnological processes, particularly as detergent additive and in the processing of poultry wastes, particularly keratinous wastes.