3.5. Effects of agitation speed on immobilized cells for maximal pectinase production
One of the most important parameters in fungal whole cell immobilization is to provide sufficient amounts of dissolved oxy-gen and nutrient to the culture. Moreover, external mass transferlimitations also are generally encountered while working with immobilized enzyme systems [33]. Therefore, the optimal agitation speed was investigated in order to overcome the external diffusion limitation in immobilized cells fermentation. It was observed that,the pectinase production increased with an increase of agitation speed from static conditions to 150 rpm, with maximum produc-tion of pectinase enzyme (9.82 U/ml) as well as fungal growth(9.07 g/L) (Fig. 5). However, agitation speed beyond 150 rpm, the enzyme production dropped. Hence, a speed of agitation at 150 rpm was chosen for further studies. According to Vijay and Rintu [33], at higher agitation rates, shearing of the enzyme molecule occurs, this