title: Penicillium echinulatum secretome analysis reveals the fungi potential for degradation of lignocellulosic biomass.
abstract: BACKGROUND
  The enzymatic degradation of lignocellulosic materials by fungal enzyme systems has been extensively studied due to its effectiveness in the liberation of fermentable sugars for bioethanol production. Recently, variants of the fungus Penicillium echinulatum have been described as a great producer of cellulases and considered a promising strain for the bioethanol industry.
  
  
  RESULTS
  Penicillium echinulatum, wild-type 2HH and its mutant strain S1M29, were grown on four different carbon sources: cellulose, sugar cane bagasse pretreated by steam explosion (SCB), glucose, and glycerol for 120 h. Samples collected at 24, 96, and 120 h were used for enzymatic measurement, and the 96-h one was also used for secretome analysis by 1D-PAGE LC-MS/MS. A total of 165 proteins were identified, and more than one-third of these proteins belong to CAZy families. Glycosyl hydrolases (GH) are the most abundant group, being represented in larger quantities by GH3, 5, 17, 43, and 72. Cellobiohydrolases, endoglucanases, β-glycosidases, xylanases, β-xylosidases, and mannanases were found, and in minor quantities, pectinases, ligninases, and amylases were also found. Swollenin and esterases were also identified.
  
  
  CONCLUSIONS
  Our study revealed differences in the two strains of P. echinulatum in several aspects in which the mutation improved the production of enzymes related to lignocellulosic biomass deconstruction. Considering the spectral counting analysis, the mutant strain S1M29 was more efficient in the production of enzymes involved in cellulose and hemicellulose degradation, despite having a nearly identical CAZy enzymatic repertoire. Moreover, S1M29 secretes more quantities of protein on SCB than on cellulose, relevant information when considering the production of cellulases using raw materials at low cost. Glucose, and especially glycerol, were used mainly for the production of amylases and ligninases.
authors.affiliation: Enzymes and Biomass Laboratory, Institute of Biotechnology, University of Caxias do Sul, Francisco Getúlio Vargas Street 1130, Caxias Do Sul, RS 95070-560 Brazil.
authors.forename: Willian Daniel Hahn
authors.initials: WDH
authors.lastname: Schneider
authors.affiliation: Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Giuseppe Maximo Scolfaro 10.000, Campinas, São Paulo 13083-970 Brazil.|Department of Biochemistry, Institute of Biology, State University of Campinas (UNICAMP), Campinas, São Paulo Brazil.
authors.forename: Thiago Augusto
authors.initials: TA
authors.lastname: Gonçalves
authors.affiliation: Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Giuseppe Maximo Scolfaro 10.000, Campinas, São Paulo 13083-970 Brazil.
authors.forename: Cristiane Akemi
authors.initials: CA
authors.lastname: Uchima
authors.affiliation: Department of Microbiology and Molecular Genetics, Oklahoma State University, 1110 South Innovation Way, Stillwater, OK 74078 USA.
authors.forename: Matthew Brian
authors.initials: MB
authors.lastname: Couger
authors.affiliation: Department of Microbiology and Molecular Genetics, Oklahoma State University, 1110 South Innovation Way, Stillwater, OK 74078 USA.
authors.forename: Rolf
authors.initials: R
authors.lastname: Prade
authors.affiliation: Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Giuseppe Maximo Scolfaro 10.000, Campinas, São Paulo 13083-970 Brazil.
authors.forename: Fabio Marcio
authors.initials: FM
authors.lastname: Squina
authors.affiliation: Enzymes and Biomass Laboratory, Institute of Biotechnology, University of Caxias do Sul, Francisco Getúlio Vargas Street 1130, Caxias Do Sul, RS 95070-560 Brazil.
authors.forename: Aldo José Pinheiro
authors.initials: AJP
authors.lastname: Dillon
authors.affiliation: Enzymes and Biomass Laboratory, Institute of Biotechnology, University of Caxias do Sul, Francisco Getúlio Vargas Street 1130, Caxias Do Sul, RS 95070-560 Brazil.
authors.forename: Marli
authors.initials: M
authors.lastname: Camassola
keywords: Biofuels; CAZymes; Lignocellulosic biomass; Penicillium echinulatum strains; Secretome