title: Production of β-xylosidase from Trichoderma asperellum KIF125 and its application in efficient hydrolysis of pretreated rice straw with fungal cellulase.
abstract: On-site cellulase and hemicellulase production is a promising way to reduce enzyme cost in the commercialization of the lignocellulose-to-ethanol process. A hemicellulase-producing fungal strain suitable for on-site enzyme production was selected from cultures prepared using wet disc-milling rice straw (WDM-RS) and identified as Trichoderma asperellum KIF125. KIF125 hemicellulase showed uniquely high abundance of β-xylosidase in the xylanolytic enzyme system compared to other fungal hemicellulase preparations. Supplementation of Talaromyces cellulolyticus cellulase with KIF125 hemicellulase was more effective than that with the hemicellulases from other fungal sources in reducing the total enzyme loading for the improvement of xylose yield in the hydrolysis of ball-milling RS, due to its high β-xylosidase dominance. β-Xylosidase in KIF125 hemicellulase was purified and classified as a glycosyl hydrolase family 3 enzyme with relatively high specificity for xylobiose. The production of KIF125 β-xylosidase in the fermentor was estimated as 118 U/g-WDM-RS (2350 U/L culture) at 48 h. These results demonstrate that KIF125 is promising as a practical hemicellulase source to combine with on-site cellulase production using T. cellulolyticus.
authors.affiliation: Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-0046, Japan. inoue-h@aist.go.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Inoue
authors.affiliation: Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-0046, Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Kitao
authors.affiliation: Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-0046, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Yano
authors.affiliation: Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto, 606-8502, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Sawayama
mesh_terms: D018533:Biomass; D003470:Culture Media; D005656:Fungal Proteins / Q000096:biosynthesis / Q000378:metabolism; D006868:Hydrolysis; D012275:Oryza / Q000382:microbiology; D013379:Substrate Specificity; D014242:Trichoderma / Q000201:enzymology / Q000254:growth & development / Q000302:isolation & purification*; D014994:Xylose / Q000378:metabolism*; D014995:Xylosidases / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D003470:Culture Media; D005656:Fungal Proteins; D014994:Xylose; D014995:Xylosidases; C026579:exo-1,4-beta-D-xylosidase
keywords: Hemicellulase; On-site enzyme production; Talaromyces cellulolyticus; Trichoderma asperellum; β-Xylosidase