title: Saccharification of Lignocelluloses by Carbohydrate Active Enzymes of the White Rot Fungus Dichomitus squalens.
abstract: White rot fungus Dichomitus squalens is an efficient lignocellulose degrading basidiomycete and a promising source for new plant cell wall polysaccharides depolymerizing enzymes. In this work, we focused on cellobiohydrolases (CBHs) of D. squalens. The native CBHI fraction of the fungus, consisting three isoenzymes, was purified and it maintained the activity for 60 min at 50°C, and was stable in acidic pH. Due to the lack of enzyme activity assay for detecting only CBHII activity, CBHII of D. squalens was produced recombinantly in an industrially important ascomycete host, Trichoderma reesei. CBH enzymes of D. squalens showed potential in hydrolysis of complex lignocellulose substrates sugar beet pulp and wheat bran, and microcrystalline cellulose, Avicel. Recombinant CBHII (rCel6A) of D. squalens hydrolysed all the studied plant biomasses. Compared to individual activities, synergistic effect between rCel6A and native CBHI fraction of D. squalens was significant in the hydrolysis of Avicel. Furthermore, the addition of laccase to the mixture of CBHI fraction and rCel6A significantly enhanced the amount of released reducing sugars from sugar beet pulp. Especially, synergy between individual enzymes is a crucial factor in the tailor-made enzyme mixtures needed for hydrolysis of different plant biomass feedstocks. Our data supports the importance of oxidoreductases in improved enzyme cocktails for lignocellulose saccharification.
authors.affiliation: Department of Food and Environmental Sciences, Division of Microbiology and Biotechnology, University of Helsinki, Helsinki, Finland.
authors.forename: Johanna
authors.initials: J
authors.lastname: Rytioja
authors.affiliation: Department of Food and Environmental Sciences, Division of Microbiology and Biotechnology, University of Helsinki, Helsinki, Finland.
authors.forename: Kristiina
authors.initials: K
authors.lastname: Hildén
authors.affiliation: Roal Oy, Rajamäki, Finland.
authors.forename: Susanna
authors.initials: S
authors.lastname: Mäkinen
authors.affiliation: Roal Oy, Rajamäki, Finland.
authors.forename: Jari
authors.initials: J
authors.lastname: Vehmaanperä
authors.affiliation: Department of Food and Environmental Sciences, Division of Microbiology and Biotechnology, University of Helsinki, Helsinki, Finland.
authors.forename: Annele
authors.initials: A
authors.lastname: Hatakka
authors.affiliation: Department of Food and Environmental Sciences, Division of Microbiology and Biotechnology, University of Helsinki, Helsinki, Finland.
authors.forename: Miia R
authors.initials: MR
authors.lastname: Mäkelä
mesh_terms: D000595:Amino Acid Sequence; D002482:Cellulose / Q000378:metabolism; D043366:Cellulose 1,4-beta-Cellobiosidase / Q000235:genetics / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D006868:Hydrolysis; D007525:Isoelectric Focusing; D042845:Laccase / Q000378:metabolism; D008031:Lignin / Q000378:metabolism*; D010455:Peptides / Q000032:analysis / Q000737:chemistry; D011124:Polyporaceae / Q000201:enzymology*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D053719:Tandem Mass Spectrometry; D014242:Trichoderma / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D010455:Peptides; D011994:Recombinant Proteins; C036909:lignocellulose; D002482:Cellulose; D008031:Lignin; D042845:Laccase; D043366:Cellulose 1,4-beta-Cellobiosidase; C109691:microcrystalline cellulose