1.Availability of Oxygen-The degree of anaerobiosis is a principal factor controlling fermentations. with yeasts. when large amounts of oxygen are present, yeast cell production is promoted.

1.人类通过研究，作为好奇而得物，已开发了批控自然过程系统。其就是通过控（也包括促进）微生物生长来保藏食物。