Optimized protocol for the pilot-scale preparation of fungal cellulase

Summary A 25-l scale protocol is devised for the optimal secretion and recovery of fungal cellulase. Using a selected higher yieldingTrichoderma viride SMC strain, a protocol consisted of: a) an optimized production medium rich in microcrystalline cellulose (MCC), fortified with 1% (w/v) ammonium sulphate, 0.5% (w/v) soybean flour, 0.1% (v/v) Tween-80 and other trace nutrients; b) optimized physical parameters of production, such as an inoculum containing a homogeneous suspension of 6×10⁷ conidia per 1,28±1°C, pH 4.0±0.5, 300±20 rpm, 11000±1000 l/h aeration, and 170–220 h duration; c) optimal recovery through a filter press (450 l/h rate of filtration) followed by precipitation with 2.5–3.0 volumes of acetone (15°C and basket centrifugation (27°C, 1700 rpm)); and d) vacuum drying (35°C, 4–6 h). This afforded 70% recovery of cellulase in the form of white fluffy powder containing 20000±2000 carboxy methyl cellulase and 1000±50 units filter paperase per g activities, with raw material cost of US$ 8–10 per million carboxy methyl cellulase units. During storage for 18 months at 4°C, ambient temperature and 37°C, the cellulase preparation was found to retain 100, 75 and 60% of its initial activity, respectively.