Saccharification of Lignocelluloses by Carbohydrate Active Enzymes of the White Rot Fungus Dichomitus squalens

• Published in: PloS one 2015-12, Vol.10 (12), p.e0145166-e0145166
• Main Authors: Rytioja, Johanna, Hildén, Kristiina, Mäkinen, Susanna, Vehmaanperä, Jari, Hatakka, Annele, Mäkelä, Miia R
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Biodiesel fuels; Biological research; Biomass; Biotechnology; Carbohydrates; Cell walls; Cellulase; Cellulose; Cellulose - metabolism; Cellulose 1,4-beta-Cellobiosidase - genetics; Cellulose 1,4-beta-Cellobiosidase - metabolism; Chromatography, High Pressure Liquid; Cloning; Coprinopsis cinerea; Crystalline cellulose; Dehydrogenases; Depolymerization; Diachus squalens; Electrophoresis, Polyacrylamide Gel; Environmental science; Enzymatic activity; Enzyme activity; Enzymes; Food; Fungal Proteins - genetics; Fungal Proteins - metabolism; Fungi; Genomics; Glucose; Hydrolysis; Isoelectric Focusing; Isoenzymes; Laccase; Laccase - metabolism; Lignin; Lignin - metabolism; Lignocellulose; Peptides - analysis; Peptides - chemistry; Phanerochaete chrysosporium; Physiological aspects; Pichia pastoris; Plant biomass; Polyporaceae - enzymology; Polysaccharides; Pulp; Recombinant Proteins - biosynthesis; Recombinant Proteins - chemistry; Recombinant Proteins - isolation & purification; Saccharides; Saccharification; Substrates; Sugar; Sugar beets; Synergistic effect; Tandem Mass Spectrometry; Trichoderma - metabolism; Trichoderma reesei; Wheat; Wheat bran; White rot; White rot fungi
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0145166

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.