title: Pectin lyase overproduction by Penicillium griseoroseum mutants resistant to catabolite repression.
abstract: Expression of pectinolytic genes is regulated by catabolic repression limiting the production of pectin lyase (PL) if the natural inducer, pectin, is missing from the growth medium. Here, we report the isolation of Penicillium griseoroseum mutants resistant to 2-deoxy-d-glucose (DG) that show resistance to catabolite repression and overproduce PL. Three spontaneous and nine UV-induced mutants were obtained. Some mutants produced sectors (segments morphologically different) that were also studied. The mutants were analyzed for pectinases production on pectinase-agar plates and five mutants and two sectors showing larger clearing zones than the wild type were selected for quantitative assay. Although PL production higher than the wild type has been found, phenotype instability was observed for most of the mutants and, after transfers to nonselective medium, the DG resistance was no longer present. Only mutants M03 and M04 were stable maintaining the DG-resistance phenotype. When growing for 120h in liquid medium containing glucose with or without pectin, both mutants showed higher PL production. In the presence of glucose as sole carbon source, the mutant M03 produced 7.8-fold more PL than the wild type. Due its phenotypic stability and PL overproduction, the mutant M03 presents potential for industrial applications.
authors.affiliation: Universidade Federal de Viçosa, Departamento de Microbiologia, Viçosa, MG, Brazil.
authors.forename: Juliana Oliveira
authors.initials: JO
authors.lastname: Lima
authors.affiliation: Universidade Federal de Viçosa, Departamento de Microbiologia, Viçosa, MG, Brazil; Embrapa Trigo, Passo Fundo, RS, Brazil.
authors.forename: Jorge Fernando
authors.initials: JF
authors.lastname: Pereira
authors.affiliation: Universidade Federal de Viçosa, Departamento de Microbiologia, Viçosa, MG, Brazil.
authors.forename: Elza Fernandes de
authors.initials: EF
authors.lastname: Araújo
authors.affiliation: Universidade Federal de Viçosa, Departamento de Microbiologia, Viçosa, MG, Brazil. Electronic address: mvqueiro@ufv.br.
authors.forename: Marisa Vieira de
authors.initials: MV
authors.lastname: Queiroz
mesh_terms: D057465:Catabolite Repression; D003470:Culture Media / Q000737:chemistry / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010368:Pectins / Q000378:metabolism; D010407:Penicillium / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D011133:Polysaccharide-Lyases / Q000378:metabolism*
chemical_list: D003470:Culture Media; D005656:Fungal Proteins; D010368:Pectins; D011133:Polysaccharide-Lyases; C027349:pectin lyase
keywords: 2-Deoxy-d-glucose; Pectinolytic complex; Spontaneous mutant; Ultraviolet mutagenesis