ABSTRACT
The influence of aeration and automatic pH control on the production of alpha-amylase by a strain of "Bacillus subtilis" NRRL 3411 from acid cheese whey was studied. Tests were carried out in a rotary shaker and in mechanically stirred ferments. Alpha-maylase was analysed according to DUN's method. Oxygen absorption rate was determined by Cooper's method. Cell oxygen demand was determined as oxygen consumption in a Warburg respirometer. The level of dissolved oxygen was mesured by means of a galvanic silver-lead electrode. Results suggest the possibility of industrial use of acid cheese whey as a carbon source for alpha-amylase production, since the yiels was similar to that produced with lactose. The highest alpha-amylase levels 100,000 DUN/ml units were not attained at highr aeration rates -431 mLO2/L.h-. The indicated value correspond to a 96 h process with automatic pH enzyme production was directly related to growth in the form of cell aggregates.