Novel Aspergillus Hemicellulases Enhance Performance of Commercial Cellulases in Lignocellulose Hydrolysis

作者：Shin Hyun Dong; Trinh Vo; Chen Rachel^*

来源：Biotechnology Progress, 2011, 27(2): 581-586.

DOI：10.1002/btpr.547

• lignocellulose hydrolysis
• hemicellulase
• cellulase
• Aspergillus fumigatus

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 beta-xylosidase), and those acting on side chains (or accessory enzymes) notably a-arabinofuranosidase and acetyl-xylan esterase. The Asperigillus hemicellulases are characterized as having relatively low xylanase and beta-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.

• 出版日期2011-4