Factors affecting production of raw-starch-digesting amylase by the soil bacterium Cytophaga sp.

A Cytophaga sp. isolated from soil had a great potential for production of raw-starch-digesting amylase. The effect of the culture conditions and medium components on enzyme production was investigated. The basal medium contained 1% polypeptone, 0.2% yeast extract, 0.5% beef extract and 0.5% raw corn starch. Enzyme production increased when both the polypeptone and raw starch contents were reduced. The optimal cultivating medium consists of 0.5% polypeptone-s, 0.2% yeast extract and 0.2% raw corn starch at pH 6.5. The enzyme activity of the culture supernatant for raw starch reached maximum (220 units/ml) after 24 h incubation at 35°C.