Hemicellulose structural changes during steam pretreatment and biogradation of Lentinus edodes

To disclosed the internal factors for the growth of mycelium and Lentinus edodes, Quercus Linn wood, which was biotransformed during the artificial cultivation of Lentinus edodes, were synergistically characterized by TGA/DTG, FT-IR and NMR. The results showed that the different ingredients of hemicellulose decreased during steam explosion and biodegradation of Lentinus edodes, however hemicellulose content continued to increased. FT-IR showed that the transmittance of the characteristic peaks in hemicellose gradually increased after decreased after steam explosion and biodegradation of Lentinus edodes. TGA/DTG curves that thermal stability and maximum thermal degradation rates of hemicelloses were contiguous after steam explosion and biodegradation of Lentinus edodes. Structural determination based on FT-IR and 1H, and 2D-HSQC NMR analyses showed that the alkali-extractable hemicelluloses shared the structure composed of (1 → 4)-linked β-d-xylopyranosyl backbone with 4-O-methyl-R-d-glucuronic acid attached to O-2 of the xylose residues and l-arabinose attached to O-3 of the xylose residues. And it revealed that the extractable hemicelluloses retained original structure without cleaving chemical linkages. Furthermore, a small amount of other minor hemicelluloses (β-glucans) including xylans in the extractable hemicelluloses could be identified by NMR and other approaches.