Production of alph-amylase in acid cheese whey culture media with automatic pH control

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.

Obtención de *-amilasa bacteriana: influencia del shock térmico y de los nutrientes del medio / Isolation of baceterial *-amylase: effect of heat shock and media nutrients

Se estudió la producción de alfa-amilasa empleando una cepa de Bacillus subtilis NRRL 3411. Las variables estudiadas incluyeron shock término, concentración y naturaleza de la fuente de carbono, nitrógeno y factores. Además se realizaron experiencias sobre estabilización de los caldos enzimáticos libres de células. Se determinó que utilizando esporos sometidos a un shock térmico de 100-C de 10 min, en un medio con lactosa, caseína, extracto de levadura y minerales, se alcanzaron valores de 140 unidades de alfa-amilasa en 72 h de proceso. También se demostró que el agregado de 20% de glicerol y 1% de benzoato de sodio aseguran caldos estabilizados a 20-C, por un período de 30 días