title: Effect of β-Mannanase and β-Mannosidase Supplementation on the Total Hydrolysis of Softwood Polysaccharides by the Talaromyces cellulolyticus Cellulase System.
abstract: Softwoods are promising lignocellulosic feedstock that provide numerous fermentable sugars via the hydrolysis of the components of cellulose and mannan-type hemicellulose such as galactoglucomannan (GGM). However, fungal cellulase systems are insufficient for the hydrolysis of softwood GGM due to the relatively low levels of mannan-degrading activities. To compensate for the deficient activities in the cellulase system, mannan-degrading enzymes were added to a cellulase preparation from Talaromyces cellulolyticus and the hydrolysis of a ball-milling-treated Douglas fir (BM-DF) was evaluated. The addition of a commercial enzyme derived from Aspergillus niger with high β-mannanase and β-mannosidase activities resulted in approximately 80 % mannose yield from BM-DF for a small protein loading amount (i.e., 1.4 mg/g substrate). Supplementation of β-mannanase and β-mannosidase purified from the commercial enzyme revealed that both enzymes were essential to improve the hydrolysis of BM-DF GGM by T. cellulolyticus cellulase. T. cellulolyticus produced inducible mannan-degrading enzymes using glucomannan as a carbon source. Supplementation of this enzyme preparation increased mannose yield from BM-DF to approximately 70 %. These results suggest that the enhancement of T. cellulolyticus β-mannosidase and β-mannanase productivity will be effective for the construction of cellulase system suitable for BM-DF hydrolysis.
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.forename: Shinichi
authors.initials: S
authors.lastname: Yano
authors.forename: Shigeki
authors.initials: S
authors.lastname: Sawayama
mesh_terms: D001234:Aspergillus niger / Q000201:enzymology*; D002480:Cellulase / Q000096:biosynthesis*; D005656:Fungal Proteins / Q000096:biosynthesis / Q000737:chemistry; D008031:Lignin / Q000737:chemistry*; D032901:Talaromyces / Q000201:enzymology*; D014934:Wood / Q000737:chemistry*; D044902:beta-Mannosidase / Q000737:chemistry*
chemical_list: D005656:Fungal Proteins; C036909:lignocellulose; D008031:Lignin; D044902:beta-Mannosidase; D002480:Cellulase