Reverse micellar extraction of fungal glucoamylase produced in solid state fermentation culture

Partial purification of glucoamylase from solid-state fermentation culture was, firstly, investigated by reverse micellar extraction (RME). To avoid back extraction problems, the glucoamylase was kept in original aqueous phase, while the other undesired proteins/enzymes were moved to reverse micellar organic phase. The individual and interaction effects of main factors, i.e. pH and NaCl concentration in aqueous phase, and concentration of AOT (sodium bis-2-ethyl-hexyl-sulphosuccinate) in organic phase were studied using response surface methodology. The optimum conditions for the maximum recovery of the enzyme were pH 2.75, 100 mM NaCl, and 200 mM AOT. Furthermore, the optimum organic to aqueous volume ratio (Vorg/Vaq) and appropriate number of sequential extraction stages were 2 and 3, respectively.Finally, 60% of the undesired enzymes including proteases and xylanases were removed from aqueous phase, while 140% of glucoamylase activity was recovered in aqueous phase and the purification factor of glucoamylase was found to be 3.0-fold