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|Type:||Artigo de periódico|
|Title:||Production and characterization of thermostable phenol oxidases of the ascomycete Thermoascus aurantiacus|
|Abstract:||The effect of some culture conditions on extracellular phenol oxidase (PO) production by the thermophilic ascomycete Thermoascus aurantiacus was studied. The effect of different lignocellulosic and an aromatic compound (p-anisidine) as inducers of PO activity was studied in liquid culture. The most effective substrate, wheat bran, induced between 1 and 2 units/ml PO activity when utilized at a concentration of 1.5% (w/v). The type and size of fungal inoculum influenced the PO production, However, the agitation of cultures did not increase PO production, An initial pH between 6 and 8 resulted in a higher PO production. The crude extracts of T. aurantiacus had activities sufficient to oxidize various typical substrates of POs in the absence of H2O2. Higher activities were attained with 2,2'-azinobis-(3-ethylthiazoline 6-sulphonate), 2,6-dimethoxyphenol and o-dianisidine. Typical inhibitors of metal-containing oxidases were the most potent inhibitors of T. aurantiacus PO. The optimal pH for o-dianisidine oxidation was 2.8 in 50 mM citrate/ phosphate buffer; the optimal oxidation temperature was between 70 and 80 degrees C. All characteristics of the crude extract indicated that the PO is a typical fungal laccase, except for the high optimal temperature.|
|Appears in Collections:||Artigos e Materiais de Revistas Científicas - Unicamp|
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