Enhanced production and physicochemical properties of thermostable crude cellulase from Sporothrix carnis grown on corn cob

• Sporothrix carnis produces high yield of cellulase on neglected agricultural biomass.
• Remarkable increase in enzyme yield by S. carnis is achieved with certain supplements.
• S. carnis produces extremely thermostable and organic solvent-tolerance cellulose.
• Broad pH stability of cellulase from S. carnis is useful for industrial applications.
• Efficacy of cellulase from S. carnis under extreme operational conditions is proposed.

Increasing demand for highly thermostable cellulases for biotechnology and industrial applications is a serious challenge. Production of thermostable cellulase from Sporothrix carnis cultivated on corn cob, a readily available and affordable agricultural residue, was investigated. Effects of some supplements such as carbohydrates, amino acids and metal ions on cellulase production were evaluated. Crude cellulase from S. carnis was characterized in order to evaluate its potentials for industrial applications. Maximum yield of cellulase (285.7 U/ml) was at 96 h of cultivation using 2.5% inoculum at pH 6.0. Xylan, glutamic acid, tyrosine and Mn2+ enhanced enzyme production with an increase of about 250%. The crude cellulase had optimum activity at 80 °C and was highly stable at elevated temperatures (50–90 °C) with residual activities above 70% after 120 min of incubation. The enzyme showed 75% residual activity after 300 min of incubation at 80 °C. The crude enzyme had optimum pH of 5.0 and was stable over wide pH range (3.0–9.0) with residual activity above 60% after 180 min of incubation. Activity of cellulase was remarkably enhanced in the presence of almost all organic solvents studied. Metal ions (Mn2+, Cu2+, Mg2+ and Fe2+) increased enzyme activity, with 350% relative activity in the presence of 5 mM Mn2+. Results reveal potentials of cellulase from S. carnis for industrial applications.