In experiments to test the effects of pH, crude enzyme from Aspergillus niger gave the highest glucoamylase activity of 3.34 U/ml at pH 5.0 shown in appendix 19. When pH was increased beyond 5.0, activity declined to 2.60 U/ml at pH 6.0 (Figure
4.7) and further down to 2.24 U/ml at pH 7.0. Activity however, increased at pH 8.0 to 3.22 U/ml. Crude enzyme from Rhizopus species gave highest glucoamylase activity of 3.11 U/ml at pH 4.5. When pH was increased beyond 4.5, activity declined to 1.64 U/ml at pH 6.0.