Author
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Saha, Badal |
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Submitted to: Process Biochemistry
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/4/2002 Publication Date: 6/1/2002 Citation: SAHA, B.C. PRODUCTION, PURIFICATION, AND PROPERTIES OF XYLANASE FROM A NEWLY ISOLATED FUSARIUM PROLIFERATUM. PROCESS BIOCHEMISTRY. 2002. V. 37. P. 1279-1284. Interpretive Summary: Corn fiber is an abundantly available low cost feedstock for production of fuel ethanol and other value-added fermentation products. For this, the corn fiber has to be broken down to simple sugars (saccharification). The structure of xylan in corn fiber is complex and commercially available enzyme preparations do not effectively hydrolyze it to simple sugars. Thus, this research was undertaken to isolate an organism that can produce enzymes for saccharification of corn fiber xylan. Xylanase is a key enzyme for xylan hydrolysis. The enzyme from one newly isolated fungal strain capable of utilizing corn fiber xylan as growth substrate has been purified and characterized. It also has potential for use in the production of xylooligosaccharides from xylan substrates and to improve animal feed digestibility by hydrolyzing a major component of animal feed. Technical Abstract: A fungus, Fusarium proliferatum (NRRL 26517), was isolated by screening soil samples surrounding decaying corn and wood using corn fiber xylan as carbon source. The extracellular xylanase from this fungal strain was purified 975-fold to homogeneity from the culture supernatant by ammonium sulfate treatment, DEAE Bio-Gel A column chromatography, octyl-Sepharose column chromatography and Bio gel A-0.5m gel filtration. The purified xylanase (specific activity 591 U/mg protein) was a monomeric glycoprotein with a molecular weight of 22,400 as determined by SDS-PAGE. The optimum pH and temperature for the action of the enzyme were at 5.0-5.5 and 55 deg C, respectively. The purified xylanase was fully stable at pH 5.0 to 7.5 and temperature up to 55 deg C. It hydrolyzed a variety of xylan substrates mainly to xylobiose and higher short-chain xylooligosaccharides. No xylose was formed. The enzyme did not require metal ions for activity and stability. |
