Production, optimization and partial purification of bacterial and fungal proteases for animal skin dehairing: A sustainable development in leather-making process

Abstract

Crude microbial protease was produced from Bacillus subtilis KM5B and Aspergillus flavus KMAF1 after their 16S/18S rDNA molecular identification with 99.59 % and 98.99 % respectively through solid state fermentation in a medium containing hair, feathers and agro wastes. The crude protease after optimization had an optimum production with Bacillus subtilis of 35 mm, enzyme activity of 123.2 U/mL at 35 °C, pH 8.0 for 48 h while A. flavus recorded 18 mm and an enzyme activity of 122.1 U/ml at 30C, pH 7.0 for 120 h. The percentage protease recovery for the B. subtilis and A. flavus were 71.5 % and 94.8 %, fold purification at 1.5 and 2.0, total protein was 107.90 mg and 150.60 mg, enzyme activity was 125.06 U/ml and 122.01 U/ml, and specific activity was 1.159 U/mg and 0.81 U/mg respectively. Therefore, protease from the two organisms have potential to dehair animal skins in tanneries industries to improve the quality of leather without environmental pollution.