Production of cellulase by Mucor ramanniacus using submerged fermentation and its applications in biodegradation of agro-industrial waste

Abstract

This study was undertaken to isolate and identify a novel cellulase-producing strain from a waste site (7°28’11’’N 4°31’24’’E), optimise the growth conditions, partially purify and biochemically characterise the enzyme. The potentials of the purified cellulase to hydrolyse the lignocellulosic component of some agro-industrial wastes (e.g. orange peels etc.) was also investigated. The best cellulase-producing fungus was identified as Mucor ramanniacus and the optimum conditions for cellulase production were pH (4.5), inoculum size (12 mm), carbon and nitrogen sources were carboxymethyl cellulose and sodium nitrate respectively resulting in a specific activity of 1423 Units/mg protein. A purification fold of 1.56 and 45.37 % yield were obtained after purification. The optimum pH and temperature were at 9.0 and 40°C respectively. The kinetic parameters were 0.63 ± 0.495 mg/ml, 20.21 ± 11.28 U/ml, 1001.4s− 1 for Km and Vmax and kcat respectively. Na+, K+, Ca+, Cysteine, β-mercaptoethanol and SDS were activators while Tween 80, Triton X-100 EDTA, Hg2+ and Ba2+ inhibited the enzyme. M. ramanniacus cellulase hydrolysed all agro-industrial wastes used. The partially purified M. ramanniacus cellulase showed great potential in biodegradation of various lignocellulosic substrates and the biochemical characteristics exhibited makes it suitable in industrial applications.