Determination of agitation and aeration conditions for scale-up of cellulolytic enzymes production by Trichoderma inhamatum KSJ1

Abstract

10 to 35 L jar fermentation scale-up cultures were performed to determine the optimum agitation and aeration rates in the cellulolytic enzymes production culture by Trichoderma inhamatum KSJ1. The optimum agitation rate in the 35 L jar fermenter was provisionally determined to be 150 rpm by using a geometrically resembled scale up method from the 10 L jar fermenter. The optimum aeration rate was determined to be 0.5 vvm by applying the mean values of superficial velocity and vvm. The DO (Dissolved Oxygen) concentration of the culture liquid was maintained below the critical DO concentration (2.336 mg/L) at 150 rpm in the 35 L jar fermenter. To increase the DO above the critical DO concentration, the agitation rate was increased from 150 to 200 rpm, with the aeration rate maintained at 0.5 vvm. As a result, the DO was maintained above critical DO concentration. The OUR (Oxygen Uptake Rate) and kLa values were 0.91 mg-DO/L·min and 11.1 hr−1, respectively. The amylase and FPase (filter paper activity) activities were 4.48 and 0.74 U/mL, respectively, in the 35 L jar fermenter, which was comparable to that in the 10 L fermenter (4.2 and 0.5 U/mL, respectively). Therefore, the scale-up conditions, 0.5 vvm and 200 rpm, were concluded to be the optimum aeration and agitation rates in the 35 L jar fermenter.