title: Nitrogen source optimization for cellulase production by Penicillium funiculosum, using a sequential experimental design methodology and the desirability function.
abstract: The present study aimed at maximizing cellulase production by Penicillium funiculosum using sequential experimental design methodology for optimizing the concentrations of nitrogen sources. Three sequential experimental designs were performed. The first and the second series of experiments consisted of a 2(4) and a 2(3) factorial designs, respectively, and in the third one, a central composite rotational design was used for better visualizing the optimum conditions. The following nitrogen sources were evaluated: urea, ammonium sulfate, peptone, and yeast extract. Peptone and ammonium sulfate were removed from the medium optimization 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 and 0.36 g/L, respectively, which were validated experimentally. By the use of the desirability function, it was possible to maximize the three main enzyme activities simultaneously, which resulted in values for FPase of 227 U/L, for CMCase of 6,917 U/L, and for beta-glucosidase of 1,375 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 the use of sequential experimental designs associated to the use of the desirability function can be used satisfactorily to maximize cellulase production by P. funiculosum.
authors.affiliation: Center of Technology, School of Chemistry, Laboratories of Bioprocess Development, Federal University of Rio de Janeiro, 21949-900, Rio de Janeiro, Brazil.
authors.forename: Roberto Nobuyuki
authors.initials: RN
authors.lastname: Maeda
authors.forename: Mariana Mello Pereira
authors.initials: MM
authors.lastname: da Silva
authors.forename: Lídia Maria Melo
authors.initials: LM
authors.lastname: Santa Anna
authors.forename: Nei
authors.initials: N
authors.lastname: Pereira
mesh_terms: D000645:Ammonium Sulfate / Q000737:chemistry / Q000378:metabolism; D001709:Biotechnology / Q000379:methods*; D002457:Cell Extracts / Q000737:chemistry; D002480:Cellulase / Q000378:metabolism*; D002482:Cellulose / Q000737:chemistry / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry*; D005285:Fermentation; D008031:Lignin / Q000737:chemistry / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D010407:Penicillium / Q000737:chemistry / Q000378:metabolism*; D010461:Peptones / Q000737:chemistry / Q000378:metabolism; D015202:Protein Engineering / Q000379:methods; D012107:Research Design; D031786:Saccharum; D014508:Urea / Q000737:chemistry / Q000378:metabolism
chemical_list: D002457:Cell Extracts; D003470:Culture Media; D010461:Peptones; D014508:Urea; D002482:Cellulose; D008031:Lignin; C027433:bagasse; D002480:Cellulase; D009584:Nitrogen; D000645:Ammonium Sulfate