[Isolation of bacterial alpha-amylase. Effect of heat shock and media nutrients].

We studied alpha-amylase production by Bacillus subtilis strain NRRL 3411, the effect of heat shock, concentration and nature of the growth factors, carbon and nitrogen source. We also considered the stability of the cell-free enzymatic culture by using spores heat shocked at 100 degrees C for 10 minutes in media containing lactose, casein, yeast extract and minerals. We achieved a final value of 1400 units of alpha-amylase after 72 h of process. It was also found that by adding 20% glycerol and 1% sodium benzoate, cultures were stable at 20 degrees C for 30 days.