Screening of Fusarium sp. for xylan and cellulose hydrolyzing enzymes and perspectives for the saccharification of delignified sugarcane bagasse

Abstract

Abstract Endophytic and phytopathogenic isolates of the genus Fusarium were evaluated for their potential to produce cellulolytic and xylanolytic enzymes. The fungi were grown under solid-state conditions using a mixture of sugarcane bagasse and wheat bran as substrate with an initial moisture of 82%. Endoglucanases (ranging from 0.20 ± 0.03 to 5.31 ± 0.30 U/g of substrate), xylanases (ranging from 4.65 ± 0.76 to 125.57 ± 8.25 U/g of substrate), β-glucosidases (ranging from 21.48 ± 3.70 to 527.17 ± 22.14 U/g of substrate) and β-xylosidases (ranging from 5.61 ± 1.25 to 40.69 ± 1.26 U/g of substrate) were produced by all isolates. Enzymatic extracts from the best xylanase producers, F. lateritum var. majus and F. sacchari var. subglutinans, were tested for their capacities in promoting saccharification of delignified sugarcane bagasse. Amounts of 200.60 ± 10.60 mg/g and 280.00 ± 19.00 mg/g of reducing sugars, mainly xylose, were obtained after enzymatic hydrolysis by F. lateritum var. majus and F. sacchari var. subglutinans extracts, respectively. Up to now these species of Fusarium have been barely explored as sources of xylanolytic enzymes capable to degrade plant biomass, but our results open perspectives for their biotechnological use in the obtainment of xylose from delignified sugarcane bagasse.