STUDIES ON THE SOLID-STATE PRODUCTION OF THERMOSTABLE ENDOXYLANASES FROM THERMOASCUS-AURANTIACUS - CHARACTERIZATION OF 2 ISOZYMES

Production of xylanases by the thermophilic fungus Thermoascus auranti acus under solid state culture (SSC) was enhanced by optimization of t he type of carbon and nitrogen source, inoculum type, moisture level a nd particle size of the carbon source. Under these conditions, yields as high as 6193 U g(-1) of carbon source were obtained. Chromogenic (f luorogenic) 4-methylumbelliferyl-beta-glycosides of xylose (MUX) and x ylobiose (MUX2) were used to characterize xylanase multienzyme compone nts, after separation by isoelectric focusing. The zymogram indicated one major and two minor xylanases and one beta-xylosidase. The major ( xylanase I) and one of the minor (xylanase II) xylanases were separate d and characterized. Both xylanases exhibited remarkable thermostabili ty. (C) 1998 Elsevier Science B.V. All rights reserved.