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United States Department of Agriculture

Agricultural Research Service

Title: Enzymatic Saccharification of Complex Heteroxylan in Corn Fiber

Author
item Saha, Badal

Submitted to: United States Japan Natural Resources Protein Panel
Publication Type: Proceedings
Publication Acceptance Date: October 19, 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 verticillioides (NRRL 26518), was isolated by screening soil samples using corn fiber xylan as carbon source. The extracellular xylanase and beta-xylosidase from this fungal strain were purified to homogeneity. The purified xylanase (specific activity, 492 U/mg protein; MW, 24,000; pI, 8.6, optimum temperature, 50 deg C; optimum pH, 5.5) released xylobiose and higher xylooligosaccharides from various xylan substrates. The purified beta-xylosidase (specific activity, 57 U/mg protein; MW, 94,000; pI, 7.8, optimum temperature, 65 deg C; optimum pH, 4.5-5.0) hydrolyzed xylobiose and higher xylooligosaccharides to xylose. The biochemical properties and modes of action of these two enzymes and their synergistic role in xylan hydrolysis are presented.

Last Modified: 11/27/2014
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