Studies of pectic enzymes produced by Talaromyces flavus in submerged and solid substrate cultures

Tons of peel and rag are generated each year by industries of citrus fruit juices. These by-products are used either for the elaboration of pectin or as substrate for enzyme production. Talaromyces flavus produces extracellul ar pectinesterase and polygalacturonase after 24 h in submerged culture sup plemented with 0.5-0.8% citrus pectin preceded by preculture for 24 h in 2% (w/v) sucrose or in solid substrate culture on passion fruit peel, lemon o r orange pulp pellets after 3-6 days of incubation. Chromatographic profile s in a CM-Sepharose column of liquid and solid cultures were very similar, consisting of one endopolygalacturonase (endo-PG I) and one pectinolytic co mplex constituted by an endopoligalacturonase (endo-PG II) and pectinestera se. Pectin and pectate lyases were undetectable in both media. In Talaromyc es flavus the synthesis of pectinases was repressed by glucose and finally controlled by the concentration of products from pectic enzymes degradation .