Role of PPase-SE in Geotrichum klebahnii, a yeast-like fungus able to solubilize pectin

ROJAS, N L; CAVALITTO, S E; MIGNONE, C F; HOURS R A

ELECTRONIC JOURNAL OF BIOTECHNOLOGY

Año: 2007 vol. 11

0717-3458

Protopectinases (PPases) constitute a heterogeneousgroup of extracellular enzymes able to release solublepectin from insoluble protopectin in plant tissues.Geotrichum klebahnii (ATCC 42397) produces PPase-SEwith endopolygalacturonase activity. PPase-SE hasbeen used for pectin extraction and maceration of planttissues. Here, the capacity of G. klebahnii to usedifferent pectins as carbon and energy sources (CES)was studied, in addition to PPase-SE capacity to releasepectin from lemon peel. The strain was unable to usepectin from different origins as CES. When G. klebahniiwas cultivated with mixtures of different amounts ofglucose and citrus pectin as CES, the biomass obtainedwas proportional to the initial concentration of glucose,which was completely consumed. In addition, itproduced PPase-SE in a glucose-containing medium. Aculture was used for the extraction of pectin from lemonpeels. Pectin was enzymatically extractedsimultaneously with tissue maceration, yielding 3.7 g of(dry) pectin per 100 g of (wet) lemon peel. Extractedpectin was not metabolized by the strain. It wasconcluded that G. klebahnii uses PPase-SE to macerate,invade and colonize plant tissues, thus releasing solublesugars to be used as CES without metabolizingsolubilized pectin.