Influence of water activity on growth and activity of Aspergillus niger for glycoamylase production in solid-state fermentation.

Growth of Aspergillus niger and glucoamylase production correlated well with the water activity of the substrate (wheat bran plus corn flour) in a solid-state fermentation. Both were maximal at an initial water activity of 0.936. Glycoamylase reached 550 units/g dry substrate after 96 h.