DIFFERENT FACTORS AFFECTING GROWTH AND AMYLASE PRODUCTION BY FUNGI INHABITING POULTRY FEEDS

Extracellular amylase synthesis by Aspergillus flavus and A. .fumigatus, isolated from poultry feeds, was studied in stationary liquid medium. Maximum mycelium and extracellular amylase were produced after 7 days of incubation at 30-degrees-C and after 5 days at 3 5-degrees-C by A. flavus and A.fumigatus, respectively. Optimal amylase yield was obtained at pH 8 and 6 by the two fungi, respectively. Amylase production did not depend on the presence of starch in the growth medium but its inclusion in the medium enhanced amylase production by A. fumigatus. Sucrose appeared to be a poor carbon source for amylase synthesis by the test fungi. Growth on varying nitrogen sources showed that glycine promoted amylase production by A.flavus while yeast extract achieved maximum enzymatic yield by A. fumigatus.