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Identification and characterisation of hemicellulases from thermophilic Actinomycetes

<p>To ensure the sustainability of bioethanol production, major attention has been directed to develop feedstocks which provide an alternative to food-crop biomass. Lignocellulosic (LC) biomass, which is chiefly composed of industrial plant residues, is a carbon-rich reservoir that is presently attracting much attention. However LC material is highly recalcitrant to bioprocessing and requires a mixture of physical and enzymatic pretreatment in order to liberate fermentable sugars. Thermostable enzymes are extremely desirable for use in thermophilic fermentations due to their inherent stability. Hemicellulose, a core constituent of LC, requires a cascade of hemicellulases to stimulate the depolymerisation of its xylan backbone. &alpha / -L-arabinofuranosidase (AFase) increases the rate of lignocellulose biodegradation by cleaving arabinofuranosyl residues from xylan thereby increasing the accessibility of other hemicellulases. Twenty thermophilic Actinomycete isolates were screened for AFase activity using pnp-arabinofuranoside as the substrate. Three strains (ORS #1, NDS #4 and WBDS #9) displayed significant AFase activity and were identified as Streptomyces species with 16S rRNA gene sequence analysis. Genomic DNA was isolated from these strains and a cosmid library constructed in the shuttle vector pDF666. Subsequent functional and PCR-based screening revealed no positive clones.</p>

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uwc/oai:UWC_ETD:http%3A%2F%2Fetd.uwc.ac.za%2Findex.php%3Fmodule%3Detd%26action%3Dviewtitle%26id%3Dgen8Srv25Nme4_8316_1306914871
Date January 2010
CreatorsMatthews, Lesley-Ann A
Source SetsSouth African National ETD Portal
LanguageEnglish
Detected LanguageEnglish
TypeThesis and dissertation
FormatPdf
CoverageZA
RightsCopyright: University of the Western Cape

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