Polygalacturonase activity of Penicillum sp 7/4B/EI 1 mutant grown on some by-products of food industry.

Pectolytic activity of the Penicillum sp 7/4B/E11 mutant, which synthesized effectively PG and was not capable of producing PE, was studied on some by-products of food industries (apple pulp, beet pulp, and mixtures of apple pulp or beet pulp with wheat bran) supplemented in some experiments with mineral salts of the Czapek's medium. The strain showed good growth but a low PG activity when grown on by-products without mineral salts and an increase in PG activity after cultivation on these by-products (mainly on beet pulp) enriched with mineral salts. The highest PG activity was obtained after 6-8 days cultivation on beet pulp (3%) with mineral salts. Among the tested salts, NaNO3 influenced PG activity most effectively, K2HPO4 and MgSO4 to a smaller degree whereas others were ineffective. The mutant did not synthesize PE under these culture conditions.