The strain of Arueobasidium pullulans NRRL Y-2311 (CCY 27-1-98), known as a hyperproducer of endo-1.4-beta-xylanase, exhibited good growth on pectin or pectate. Growth on these carbon sources is associated with an inducible production of significant amounts of pectolytic enzymes, of which exopolygalacturonase (EC 3.2.1.67) and endopolygalacturonase (EC 3.2.1.15) were identified. The two enzymes are not produced on D-glucose or under carbon starvation conditions. The enzymes can be induced in glucose-grown cells by D-galacturonic acid and its oligomers. Thus, D-galacturonic acid, the monomer derived from the polysaccharide, appears to be the natural inducer or a precursor of an inducer of pectolytic enzymes in the studied yeast.