Effect of mechanical agitation on the production of cellulases by Trichoderma reesei RUT-C30 in a draft-tube airlift bioreactor

With the aim to produce cellulases and to study the effect of mechanical agitation, a 35 L draft-tube airlift bioreactor equipped with a mechanical impeller was developed and validated to grow Trichoderma reesei RUT-C30 in a cellulose culture medium with lactose and lactobionic acid as fed batch. Cultures carried out without mechanical agitation resulted in higher volumetric enzyme productivity (200 U L-1 h(-1)), filter paper activity (17 U mL(-1)), carboxymethyl cellulase activity (11.8 U mL(-1)) and soluble proteins (3.2 mg mL(-1)) when compared to those with agitation. Stereo and polarized light microscopy analyses reveal that mechanical agitation resulted in shorter mycelial hyphae and larger numbers of tips. (C) 2010 Elsevier B.V. All rights reserved.