Forschungs- & Entwicklungsinformationsdienst der Gemeinschaft - CORDIS

Cellulases and hemicellulases from the thermophilic fungus Thermoascus aurantiacus

The research concerns obtaining high yields of stable and efficient enzymes from a thermophilic fungus, Thermoascus aurantiacus, which produces a complete cellulase and hemicellulase enzyme system, for use in valorization of agricultural wastes of agronomic importance from colder (wheat straw) and warmer (sorghum bagasse) regions of the European Community.

To date, a number of proteins enzymes have been isolated, purified and screened for use in saccharification, textiles, stone-washing and animal feed. Crude filtrates fractionated using ion-exchange, gel filtration, chromato-focusing and affinity chromatographies yielded 7 cellulases and 6 hemicellulases. The major beta-glucosidase, the major endoglucanase and the major endoxylanase have been characterized and the N-terminal sequence of 4 cellulase components investigated. In addition, antibodies have been raised for six cellulase components and the amino acid composition of all seven cellulase components have been determined. Enzyme purification and characterization was aided by the synthesis of specific affinity gels, model cello-oligosaccharides, specific ligands and inhibitors. Scale up of production and evaluation of low-cost culture medium were investigated for both submerged culture and solid state fermentation. Mutagenesis and cloning to enable the more interesting proteins to be expressed in other systems and/or to provide information which could enable the thermal stability of existing systems to be improved, as well as to increase the yield of protein and decrease end product and catabolic inhibition, have both proved more difficult than anticipated. Structural studies have been initiated with production of good crystals and subsequent X-ray data-sets for the major endoglucanase and endoxylanase, which are currently being resolved.

Kontakt

James COOMBS
Tel.: +44-1635-524064
Fax: +44-1635-529322
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