Response surface methodology based optimization of keratinase production from Trichoderma harzianum isolate HZN12 using chicken feather waste and its application in dehairing of hide

Keratin proteins are a major constituent of feathers which largely contribute to environmental pollution. The present study reports a potent feather degrading fungi isolated from soil and molecularly characterized (18S rDNA gene sequencing) and identified as Trichoderma harzianum isolate HZN12 (KP235366). Assessment of keratinase production from the isolate revealed better production under solid state fermentation (SSF) conditions (1320 U/g) over submerged (185 U) using chicken feathers. The effect and contribution of independent process variables were studied by Plackets-Burman design. Additionally, statistical modeling by central composite design of response surface methodology was applied to optimize the culture conditions for keratinase production under SSF. Maximum keratinase production (10,150 U/g) was validated with a 7.7 fold increase under the optimized conditions (chicken feather meal 3 g/20 ml, yeast extract 0.2%, glucose 0.9%, pH 8.5 and temperature of 37 degrees C) with a correlation coefficient (R-2) = 95.56%. Keratinase was employed for dehairing of goat hide and assessed based on different organoleptic properties. The keratinase dehaired skin exhibited superior properties in comparison to the chemical treatment. Furthermore, keratinase also showed good stability and compatibility with the tested commercial detergents making it suitable for industrial applications such as, leather and detergent industries. The results suggest an ecofriendly approach for biodegradation of chicken feather waste.