To investigate the effect of temperature on glucoamylase production, crude culture filtrates of Aspergillus niger and Rhizopus species produced from inoculated substrates mixed with the appropriate mineral salts solution; and had been incubated at 30ºC, 40ºC and 50ºC for 24 hours, 48 hours, 72 hours, 96 hours and 120 hours were obtained as described in section 3.4 and glucoamylase activities determined as described in section 3.4.1.