Double Mutants of Cellulomonas biazotea for Production of Cellulases and Hemicellulases following Growth on Straw of a Perennial Grass

Summary

Deoxyglucose-resistant mutants of Cellulomonas biazotea secreted elevated levels of cellulases and xylanases. The production of β-glucosidase in the constitutive mutant was increased 5-fold over its parent strain. This mutant showed an approximately 1.6-fold enhanced productivity of extracellular endo-glucanase following growth on Leptochloa fusca over the mutant parent. Extracellular production of xylanase, filter-paper cellulase (FPase) and endo-glucanase (CMCase) were also altered in the mutant. Maximum volumetric productivities for xylanase, β-xylosidase, FPase, β-glucosidase and endo-glucosidase were 451, 98, 80, 95, and 143 IU  l⁻¹ h⁻¹ which were significantly more than their respective values from the parental strains. The enzyme preparation of the mutants exhibited improved saccharification of kallar grass straw.