PRODUCTION OF EXTRACELLULAR XYLANASES BY PENICILLIUM-JANTHINELLUM - EFFECT OF SELECTED GROWTH-CONDITIONS

Xylanase production by Penicillium janthinellum using 10-100 mM of 2,2-dimethylsuccinate (DMS) buffer, in a range of PH 4.5-6.0 was studied. The enzyme activity was enhanced using oat xylan as the carbon source. Under these conditions a culture produced 1.14 mu mol/min (11.4 U/mL or 84.4 U/mg) of beta-xylanase after 5 d of growth in a 10-mM buffer solution at PH 4.5. Protease was absent in the DMS buffer except when 100 mM phosphate buffer at PH 6.0 was used (4 U/mL). beta-Xylosidase was only found at a PH of 4.5 in all the buffer concentrations. At a 50 mM DMS buffer concentration at pH 4.5 beta-xylanases were induced by both oat and birch xylans, having a greater effect with oat spelt xylans. Electrophoretic analyses showed that the birchwood xylan induction exhibited different proteins profiles. No beta-xylosidase or beta-glucosidase was induced until d 5. The beta-xylanases were rapidly inactivated at 50 degrees C, however, birch xylanase appeared to be more stable than oat xylanase.