PRODUCTION OF PHYTASE BY ASPERGILLUS-FICUUM AND REDUCTION OF PHYTIC ACID CONTENT IN CANOLA-MEAL

Production of the phytase (EC 3.1.3.8) from Aspergillus ficuum in a submerged batch process was inhibited by high concentrations of glucose. The inhibition was overcome by applying a fed batch technique in the production of the enzyme. Tests carried out at different oxygen concentrations revealed that aeration had a beneficial effect on the production of the enzyme. The enzyme showed an optimum pH and temperature of 5.0 and 60-degrees-C, respectively. Preincubation of the enzyme preparation at 60-degrees-C resulted in relatively fast denaturation of the enzyme. Upon storage at 4-degrees-C it lost only 15% of its activity in 5 weeks. Aspergillus ficuum also produced phytase when grown on canola meal by a solid state technique. The enzyme catalysed degradation of the phytic acid present in the meal and completely eliminated it, rendering the commodity more suitable for animal feed. An apparent 10% increase in protein content of the canola meal was noted as a result of the growth of the microorganism.