Novel Aspergillus hemicellulases enhance performance of commercial cellulases in lignocellulose hydrolysis.

Hyun-Dong Shin; Trinh Vo; Chen, Rachel

A novel hemicellulase-producing fungal strain was isolated from a local soil sample. The organism is identified as Aspergillus fumigatus based on ribosomal RNA analyses. The Aspergillus strain, designated as 2NB, produces both enzymes acting on xylan backbone (xylanase and β-xylosidase), and those acting on side chains (or accessory enzymes) notably α-arabinofuranosidase and acetyl-xylan esterase. The Asperigillus hemicellulases are characterized as having relatively low xylanase and β-xylosidase activities but high side chain removal activities. The activity ratio of side-chain acting enzymes to xylanase is higher than that of the Multifect enzyme, a commercial hemicellulase product. The potential of the novel hemicellulases in lignocelluloses bioprocessing was demonstrated with alkaline-pretreated switchgrass as lignocellulose substrate with hemicellulase supplemented with a ratio of xylanase activity to filter paper unit of 2:1. Supplement of Aspergillus hemicellulases to commercial cellulases significantly enhanced the hydrolysis of lignocellulose, achieving a 94% hydrolysis yield based on reducing sugar measurement, compared to 60% when no hemicellulase or 75% when Multifect enzyme was used under otherwise identical conditions. The significant improvement resulting from supplementing a hemicellulase mix with high side-chain removal activities suggests the importance of accessory hemicellulases in lignocellulose processing. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011

LIGNOCELLULOSE; HYDROLYSIS; ASPERGILLUS fumigatus; CARBON; PETROLEUM; BIOMASS energy

Biotechnology Progress, 2011, Vol 27, Issue 2, p581

8756-7938

Academic Journal

10.1002/btpr.547