Regulation of xylanase in Aspergillus phoenicis: a physiological and molecular approach
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Microbial xylanolytic enzymes have a promising biotechnological potential, and are extensively applied in industries. In this study, induction of xylanolytic activity was examined in Aspergillus phoenicis. Xylanase activity induced by xylan, xylose or β-methylxyloside was predominantly extracellular (93–97%). Addition of 1% glucose to media supplemented with xylan or xylose repressed xylanase production. Glucose repression was alleviated by addition of cAMP or dibutyryl-cAMP. These physiological observations were supported by a Northern analysis using part of the xylanase gene ApXLN as a probe. Gene transcription was shown to be induced by xylan, xylose, and β-methylxyloside, and was repressed by the addition of 1% glucose. Glucose repression was partially relieved by addition of cAMP or dibutyryl cAMP.
KeywordsFungi Aspergillus phoenicis Xylanase cAMP Gene transcription
This work was supported by grants from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), and Conselho de Desenvolvimento Científico e Tecnológico (CNPq). M.C.B.; H.F.T.; J.A.J. and M.L.T.M.P. are Research Fellows of CNPq. A.C.S.R., F.Z.F. and S.C.P.N are Doctors recipient from CNPq. This work is part of A.C.S.R. thesis. The authors thank Ricardo Fernandes Alarcon, and Mauricio de Oliveira for technical assistance.
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