EFFECT OF DIFFERENT INORGANIC NITROGEN SOURCES ON THE PRODUCTION OF CELLULASE-FREE β-1,4-XYLANASE BY AUREOBASIDIUM PULLULANS
 
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Pol. J. Food Nutr. Sci. 1999;49(3):39–48
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ABSTRACT
The effect of different levels of inorganic nitrogen sources (0.15, 0.21 and 0.25% nitrogen content) on the synthesis of cellulase-free β -1,4-xylanase by Aureobasidium pullulans DSM-73015 was examined. Among inorganic nitrogen compounds tested, ammonium nitrate (NH4NO3) was the best inorganic nitrogen source at 0.21% nitrogen content that gave the highest volumetric and specific activities (8830.09 nkat mL-1; 10767.15 nkat/mg protein) after 96 h of cultivation, while urea displayed the lowest effect. Partial characterization of this crude enzyme produced after optimization processes on two different buffer systems showed that its optimum pH activity was 4, while the thermoactivity had its maximum at 500C in both buffers. The highest volumetric and specific activities obtained were 20102.35 nkat mL-1; 23000.40 nkat/mg protein for sodium acetate buffer and 19852.30 nkat mL-1; 22714.31 nkat/mg protein for sodium citrate buffer.
ISSN:1230-0322