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Identification and characterization of d-xylose reductase involved in pentose catabolism of the zygomycetous fungus Rhizomucor pusillus

Paper ID Volume ID Publish Year Pages File Format Full-Text
20307 43168 2015 8 PDF Available
Title
Identification and characterization of d-xylose reductase involved in pentose catabolism of the zygomycetous fungus Rhizomucor pusillus
Abstract

Rhizomucor pusillus NBRC 4578 efficiently produces ethanol from lignocellulosic biomass because of its ability to ferment not only d-glucose, but also d-xylose. When the strain was cultivated on d-xylose, ethanol was gradually formed in the culture medium with a decrease in d-xylose and the simultaneous accumulation of xylitol, which suggested that the strain catabolized d-xylose with d-xylose reductase (XR) and xylitol dehydrogenase (XDH). XR (RpXR) was purified to homogeneity from the crude extract prepared from the mycelia of the strain grown on d-xylose. The purified enzyme was found to be NADPH-dependent and prefer pentoses such as d-xylose, d-ribose, and l-arabinose as substrates. Isolation of the genomic DNA and cDNA of the xyl1 gene encoding RpXR revealed that the gene was interrupted by two introns and the exon of the gene encoded a protein composed of 322 amino acids with a Mr of 36,724. Phylogenetic analysis showed that RpXR is more related to 4-dihydromethyltrisporate dehydrogenases from Mucoraseae fungi rather than the previously reported fungal XRs. Quantitative real-time PCR indicated that transcription of the xyl1 gene was marked in the presence of d-xylose and l-arabinose, but was week in the presence of d-glucose. These biochemical and expression analyses suggest that RpXR is involved in the catabolism of l-arabinose as well as d-xylose. This is the first report of the purification, characterization, and gene cloning of XR from zygomycetous fungi.

Keywords
Pentose catabolism; d-Xylose reductase; Rhizomucor pusillus; Zygomycetous fungus; 4-Dihydromethyltrisporate dehydrogenase
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Identification and characterization of d-xylose reductase involved in pentose catabolism of the zygomycetous fungus Rhizomucor pusillus
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Bioscience and Bioengineering - Volume 119, Issue 1, January 2015, Pages 57–64
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us