Statistical optimization of mineral salt and urea concentration for cellulase and xylanase production by Penicillium echinulatum in submerged fermentation

Abstract

Penicillium echinulatum S1M29 is a mutant with cellulase and xylanase production comparable to the most studied microorganisms in the literature. However, its potential to produce these enzymes has not been fully investigated. This study aimed at optimizing salt and urea concentrations in the mineral solution, employing the response surface methodology. A 2 5-1 Fractional Factorial Design and a 2 3 Central Composite Design were applied to elucidate the effect of salts and urea in enzyme production. Lower concentrations of KH 2 PO 4 (2.0 g.L -1), (NH 4) 2 SO 4 (1.4 g.L -1), MgSO 4.7H 2 O (0.375 g.L -1) and CaCl 2 (0.375 g.L -1) were most suitable for the production of all enzymes evaluated. Nevertheless, higher concentrations of urea (0.525 g.L -1) gave the best results for cellulase and xylanase production. The maximum FPase (1,5 U.m.L -1), endoglucanase (7,2 U.m.L -1), xylanase (30,5 U.m.L -1) and β-glucosidase (4,0 U.m.L -1) activities obtained with the planned medium were, respectively, 87, 16, 17 and 21% higher when compared to standard medium. The experimental design contributed to adjust the concentrations of minerals and urea of the culture media for cellulase and xylanase production by P. echinulatum, avoiding waste of components in the medium.