Efficient production of lignocellulolytic enzymes xylanase, -xylosidase, ferulic acid esterase and -glucosidase by the mutant strain Aspergillus awamori 2B.361 U2/1

ABSTRACT

The production of xylanase, -xylosidase, ferulic acid esterase and -glucosidase by Aspergillus awamori 2B.361 U2/1, a hyper producer of glucoamylase and pectinase, was evaluated using selected conditions regarding nitrogen nutrition. Submerged cultivations were carried out at 30 ºC and 200 rpm in growth media containing 30 g wheat bran/L as main carbon source and either yeast extract, ammonium sulfate, sodium nitrate or urea, as nitrogen sources, in all cases it was used a fixed molar carbon to molar nitrogen concentration of 10.3. The use of poor nitrogen sources favored the accumulation of xylanase, -xylosidase and ferulic acid esterase to a peak concentrations of 44,880, 640 and 118 U/L, respectively, for sodium nitrate and of 34,580, 685 and 170 U/L, respectively, for urea. However, the highest -glucosidase accumulation of 10,470 U/L was observed when the rich organic nitrogen source yeast extract was used. The maxima accumulation of filter paper activity, xylanase, -xylosidase, ferulic acid esterase and -glucosidase by A. awamori 2B.361 U2/1 was compared to that produced by Trichoderma reesei Rut-C30. The level of -glucosidase was over 17-fold higher for the Aspergillus strain, whereas the levels of xylanase and -xylosidase were over 2-fold higher. This strain also produced ferulic acid esterase (170 U/L), which was not detected in the T. reesei culture.(AU)