Pilot scale production of a Trichoderma reesei endo-β-glucanase by brewer's yeast

Endo-β-glucanase I (EGI) of Trichoderma reesei was produced in laboratory and pilot scale using recombinant strains of "bottom-fermenting" Saccharomyces cerevisiae. The gene egl1 was integrated in the chromosome or an expression cassette was inserted on a multicopy plasmid. Expression levels were compared in a laboratory scale bioreactor. The best EGI-producing strain was cultivated in pilot scale. Adsorbent treatment was used to remove endogenous yeast proteins and other impurities from the culture filtrate during concentration. Effective pilot scale one-step purification of the EGI protein was obtained using DEAE-Sepharose, on which EGI was weakly bound. The purified enzyme reacted with antibodies prepared against T. reesei EGI and catalyzed the hydrolysis of both insoluble and soluble substrates.