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 120 h 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.

Microbial Pectinases: A Review on Molecular and Biotechnological Perspectives

“…Several fungal pectin lyase genes (pelA, pelB) had been isolated and characterized from Aspergillus niger (Gysler et al, 1990;Kusters-van et al, 1991;Kusters-van et al, 1992), A. oryzae (Kitamoto et al, 2001). Recently, Lima et al, (2017) reported that expression of pectinolytic genes is regulated by catabolic repression. In presence of easily available metabolites, CreA-like protein binds at the promoters of gene (5-SYGGRG-3) to inhibit the gene transcription (Kiesenhofer, 2016).…”

Revisiting microbial pectinases: An understanding between structure-functional relationship in the arena of genetic engineering

“…In addition, other than physical-induced mutations such as UV-induced spontaneous mutations have been reported in Penicillium griseoroseum mutant strains which leads to 7.8-fold greater yield than the normal type [89]. Some recent findings showed that that Pel (BacPelA) gene from Bacillus clausii expressed in E. coli can increase the pectinase production up to 8378.2 U/ml [90] whereas endo polygalacturanase acid stable gene from Penicillium oxalicum and Aspergillus aculeatus, respectively, expressed in P. pastoris can increase the pectinase production up to 1828.7 U/ml [91] and 2408.7 U/ml [92], respectively. Similar trend was observed during expression gene encoding polygalcturonase from plasmid pAN52pgg2 in P. griseoroseum resulting 266-fold greater production of pectin lyase and 27-fold greater times of polygalacturonase than the normal strain [93].…”