Overproduction of Polygalacturonase by Penicillium griseoroseum Recombinant Strains and Functional Analysis by Targeted Disruption of the pgg2 Gene

Inactivation of the pgg2 gene, a polygalacturonase-encoding gene from Penicillium griseoroseum, reduced the total activity of polygalacturonase (PG) by 90 % in wild-type P. griseoroseum, which indicates that the pgg2 gene is the major gene responsible for PG production in this species. To increase PG production, the coding region of the pgg2 gene was cloned under the control of the glyceraldehyde 3-phosphate dehydrogenase (gpd) promoter and the terminator region of the tryptophan synthase (trpC) gene from Aspergillus nidulans (pAN52pgg2 vector). This vector was then used to transform P. griseoroseum. The transformed strains were characterized according to PG production using glucose, sucrose, or sugar cane juice as the carbon sources. The recombinant P. griseoroseum T146 strain contained an additional copy of the pgg2 gene, which resulted in a 12-fold increase in PG activity when compared with that detected in the supernatant of the control PG63 strain. The proteins secreted by the recombinant strain T146 showed a strong band at 38 kDa, which corresponds to the molecular weight of PG of the P. griseoroseum. The results demonstrate the significant biotechnological potential of recombinant P. griseoroseum T146 for use in PG production.