Amylase Production by Rhizopus nigricans Using Mashed Maize

Rhizopus nigricans isolated from stagnant water was studied as a source of amylase using boiled mashed maize (yellow variety) as sole source of carbon, while ammonium sulphate was used as nitrogen source. Concentrations of mashed maize and ammonium sulphate were 50g/l and 20g/l respectively. These levels were optimal for growth and amylase production at 30C and pH 6.0. Partial purification of the enzyme by salting, desalting and elution using DEAE-Sephadex A 50 were carried out to increase enzyme activity. Amylase activities using some native starches as test substrates showed a maximum of 7.0U/L for rice starch, followed by potato starch 6.5U/L. Mashed maize, therefore, could serve as sole source of carbon for amylase production by Rhizopus nigricans.