Production, Partial Purification and Characterization of Enzyme Cocktail from Trichoderma citrinoviride AUKAR04 Through Solid-State Fermentation
Résumé
A strain of Trichoderma citrinoviride AUKAR04 was identified on the basis of morphological and 5.8S ribosomal RNA sequencing [GenBank: KF698728]. It produces cocktail of enzymes such as xylanase (55,000 IU gds−1), CMCase (375 IU gds−1) and β-1,3-glucanase (695 IU gds−1) after 72 h under solid-state fermentation. These enzymes were partially purified by a three-phase partitioning method, which recovered the maximum activities of xylanase (99.8 %) with 5.7-fold, CMCase (96.5 %) with 5.5-fold and β-1,3-glucanase (98.4 %) with 5.6-fold purification. The maximum activity of xylanase was observed at pH 5.0, CMCase at pH 5.0–6.0 and β-1,3-glucanase at pH 6.0. Optimum temperature of xylanase and β-1,3-glucanase was found to be at 50 °C, while for CMCase was at 60 °C. The activities of these enzymes were enhanced by Mg2+ and Mn2+ ions. Eucalyptus pulp fiber was incubated for 14 h with the enzyme cocktail. Xylanase hydrolyzed the pulp to yield arabinose (475 mg L−1) and xylose (1795 mg L−1), CMCase and β-1,3-glucanase released glucose (18763 mg L−1). The length of fiber was reduced from 0.881 to 0.056 mm. This is indicative of the potential application on bioconversion of lignocellulosic biomass into fermentable sugars by the enzyme cocktail produced from T. citrinoviride AUKAR04 for sustainable production of bioethanol.