The aim of this work was to study the influence of phosphate concentrations on glucoamylase production by the fungus Aspergillus awamori. In culture media containing cassava flour, different levels of phosphates were tested and the fungal responses to increasing levels (whether or not coupled to pH adjustment throughout the run) were assessed in terms of the resulting glucoamylase production. Phosphate increments, associated with pH readjustments throughout the run, yielded around 1,200 U/L of quite stable glucoamylase activity in the broth, while under a conventional condition (low phosphate without pH readjustment), enzymatic activity was around 350 U/L, which decayed dramatically towards the end of the cultivation