Submitted to: Society of Industrial Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 2, 2001
Publication Date: N/A
Technical Abstract: Corn fiber can serve as a low cost carbohydrate feedstock for production of fuel ethanol and other value-added fermentation products. The structure of arabinoxylan in corn fiber is very complex and commercially available hemicellulase preparations do not effectively saccharify it. A fungus Fusarium proliferatum (NRRL 26517) was isolated by screening soil samples using corn fiber xylan as carbon source. The production of xylanase, beta-xylosidase, and alpha-L-arabinofuranosidase by the organism was studied. The extracellular xylanase and beta-xylosidase from this fungal strain were separately purified to homogeneity. The purified xylanase (specific activity, 591 U/mg protein; MW, 22,000; optimum temperature, 55 deg C; optimum pH, 5.0-5.5) released mostly xylobiose and xylotriose or xylotetraose from xylan substrate depending on the source. The purified beta-xylosidase (specific activity, 53 U/mg protein; MW, 91,000; optimum temperature, 60 deg C; optimum pH, 4.5) hydrolyzed xylobiose and higher xylooligosaccharides to xylose. The detailed biochemical properties and modes of action of these two enzymes and their synergistic role in xylan hydrolysis will be presented.