Thermotolerant hemicellulolytic and cellulolytic enzymes from Eupenicillium parvum 4-14 display high efficiency upon release of ferulic acid from wheat bran.

Abstract

To characterize the hemicellulolytic and cellulolytic enzymes from novel fungi, and evaluate the potential of novel enzyme system in releasing ferulic acid (FA) from biomass resource. A hemicellulolytic and cellulolytic enzyme-producing fungus 4-14 was isolated from soil by Congo red staining method, and identified as Eupenicillium parvum based on the morphologic and molecular phylogenetic analysis. The optimum temperature of fungal growth was 37°C. Hemicellulolytic and cellulolytic enzymes were produced by this fungus in solid-state fermentation (SSF), and their maximum activities were 554, 385, 218, 2·62 and 5·25Ug(-1) for CMCase, xylanase, β-glucosidase, FPase and FAE respectively. These enzymes displayed the best catalytic ability at low pH values (pH 4·5-5·0). The optimum temperatures were 70°C, 70°C, 75°C and 55°C for CMCase, β-glucosidase, xylanase and FAE respectively. CMCase, xylanase and FAE were stable at different pHs or high temperature (60°C). Enzymatic hydrolysis experiment indicated that the maximum (76·8±4)% of total alkali-extractable FA was released from de-starched wheat bran by the fungal enzyme system. High activities of thermotolerant CMCase, β-glucosidase, xylanase and FAE were produced by the newly isolated fungus E.parvum 4-14 in SSF. The fungal enzyme system displayed high efficiency at releasing FA from wheat bran. This study provides a new fungal strain for researches of novel hemicellulolytic and cellulolytic enzymes and will improve the bioconversion and utilization of agricultural by-products.