Author(s): LIMA, J. O.; PEREIRA, J. F.; ARAÚJO, R. F. de; QUEIROZ, M. V. de

Summary: Expression of pectinolytic genes is regulated by catabolic repression limiting the productionof 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 spontaneousand nine UV-induced mutants were obtained. Some mutants produced sectors (segmentsmorphologically different) that were also studied. The mutants were analyzed for pectinasesproduction on pectinase-agar plates and five mutants and two sectors showing larger clear-ing zones than the wild type were selected for quantitative assay. Although PL productionhigher than the wild type has been found, phenotype instability was observed for most ofthe mutants and, after transfers to nonselective medium, the DG resistance was no longerpresent. Only mutants M03 and M04 were stable maintaining the DG-resistance phenotype.When growing for 120 h in liquid medium containing glucose with or without pectin, bothmutants showed higher PL production. In the presence of glucose as sole carbon source, themutant M03 produced 7.8-fold more PL than the wild type. Due its phenotypic stability andPL overproduction, the mutant M03 presents potential for industrial applications.

Publication year: 2017

Types of publication: Journal article

Unit: Embrapa Dairy Cattle

Keywords: Microbiologia, Mutação, Pectinolytic complex, Spontaneous mutant, Ultraviolet mutagenesis