Nitrogen Source Optimization for Cellulase Production by Penicillium funiculosum, using a SequentialExperimental Design Methodology and the Desirability Function

摘要

The present study aimed at maximizing cellulase production by Penicilliumfuniculosum using sequential experimental design methodology for optimizing the concentrationsof nitrogen sources. Three sequential experimental designs were performed. The firstand the second series of experiments consisted of a 24 and a 23 factorial designs, respectively,and in the third one, a central composite rotational design was used for better visualizing theoptimum conditions. The following nitrogen sources were evaluated: urea, ammonium sulfate,peptone, and yeast extract. Peptone and ammonium sulfate were removed from the mediumoptimization since they did not present significant statistical effect on cellulase production.The optimal concentrations of urea and yeast extract predicted by the model were 0.97 and0.36 g/L, respectively, which were validated experimentally. By the use of the desirabilityfunction, it was possible to maximize the three main enzyme activities simultaneously, whichresulted in values for Fpase of 227 U/L, for CMCase of 6,917 U/L, and for β-glucosidase of1,375 U/L. These values corresponded to increases of 3.3-, 3.2-, and 6.7-folds, respectively,when compared to those obtained in the first experimental design. The results showed that theuse of sequential experimental designs associated to the use of the desirability function can beused satisfactorily to maximize cellulase production by P. funiculosum.