Production of amylases by Aspergillus tamarii

A strain of Aspergillus tamarii, a filamentous fungus isolated from soil, was able to produce both Ó-amylase and glucoamylase activities in mineral media supplemented with 1(per cent) (w/v) starch or maltose as the carbon source. Static cultivation led to significantly higher yields than those obtained using shaking culture. The production of amylases was tolerant to a wide range of initial culture pH values (from 4 to 10) and temperature (from 25 to 42degree C). Two amylases, once Ó-amylase and one glucoamylase, were separated by ion exchange chromatography. Both partially purified enzymes had optimal activities at pH values between 4.5 and 6.0 and were stable under acid conditions (pH 4.0-7.0). The enzymes exhibited optimal activities at temperatures between 50(degree) and 60(degree) C and wete stable for more than ten hours at 55(degree) C.

Production of glucoamylase by fed-batch culture of Aspergillus awamori NRRL3112

A produçäo de amiloglicosidase por Aspergillus awamori NRRL3112 em processo descontínuo alimentado é 92 por cento superior em relaçäo ao processo descontínuo em cultivos com 20g/l de concentraçäo total de fonte de carbono oriunda de farinha de mandioca. Uma análise da velocidade específica de produçäo mostra ser este resultado decorrente da reduçäo do efeito repressivo causado pela glicose, já que o efeito indutivo, relacionado à concentraçäo de polissacarídeo, também foi reduzido

Effect of various organic compounds on synthesis of glucoamylase by an isolated strain Penicillium italicum.

Yeast extract (0.5%) stimulates the production of glucoamylase and cell synthesis while methylene blue (0.1 mM) activates the synthesis of glucoamylase. Studies on the metabolic changes during fermentation of glucoamylase in a selected medium by P. italicum show that the rate of production of glucoamylase and cellular growth are greatly accelerated between 48 and 168 hr. Rapid growth of cells during this period may account for enhanced utilization of maltose and NH4NO3 from the medium. The acid production remains constant from 48 to 144 hr. Different forms of nitrogen decrease steadily. Although methylene blue stimulates the production of glucoamylase in the broth it has practically no effect on the rate of utilization of amino and total nitrogen from the broth.