Semicontinuous production of cellulolytic enzymes withTrichoderma reesei Rutgers C30 in an aqueous two-phase system

Abstract

Cellulolytic enzyme production was studied in an aqueous twophase system, PEG 8000 5%-Dextran 7%, withTrichoderma reesei Rutgers C30 in a 7L fermentor. In batch cultivations, an average of 2.5 filter paper units (FPU)/mL were obtained in the top phase. In cultiva tions in regular media without polymers, the same enzyme concen tration was obtained. The enzyme yield was 205 FPU/g cellulose in the phase system, and 259 FPU/g cellulose in the regular medium. An extractive fed-batch cultivation was maintained in the aqueous twophase system for 360 h. The enzyme containing top phase was with drawn after phase separation. New cellulose substrate and nutrients were added with the new top phase. The enzyme extraction was started after 120 h of cultivation, and was repeated every 72 h. The total substrate concentration was 40 g/L. A maximum enzyme concentration of 4.8 FPU/mL was obtained in the withdrawn cell-free top phase. The enzyme yield was 148 FPU/g cellulose.