Culture-based strategies to enhance cellulase enzyme production from Trichoderma reesei RUT-C30 in bioreactor culture conditions

Abstract

Filamentous fungi Trichoderma reesei are considered to be one of the most efficient hyper producers of cellulase that is used in industry. Cellulase production by T. reesei was carried out using high concentration of cellulose to substitute glucose with the aim to improve cellulase production while trying to reduce production costs. The experiments were conducted separately as fed batch growth with T. reesei cultured using four media in a 7 L stirred tank bioreactor. A mixture of lactose and lactobionic acid was added into the bioreactor as cellulase inducers. The use of a cellulose–yeast extract culture medium yielded the highest enzyme and cell production with a volumetric enzyme activity of 69.8 U L −1 h −1, a filter paper activity of 5.02 U mL −1, a CMCase activity of 4.2 U mL −1, and a fungal biomass of 14.7 g L −1. The biomass concentration as a function of time was constant with relatively rapid, early growth on easily metabolized growth medium components (yeast extract), followed by a second slower growth phase due to hydrolysis of cellulose, which follow cellulase concentration augmentation. The costs to produce 1 L of production medium in laboratory-scale experiments were calculated to compare the tested media.