Fermentation ofBacillus

The products in commerce today that are produced by Bacillus fermentations include enzymes antibiotics , and insecticides. This chapter focuses on the basic principles necessary for an understanding of growth and product production in Bacillus spp. The authors show the important link between some very basic observations and how these can be (and need to be) applied in medium development processes, choice of equipment, and elimination of bottlenecks in production. Using protease production as a model, examples show the potential value of using controlled fermentations in identifying some of the limitations of product formation in Bacillus spp. Bacillus spp. as a class are known to secrete a large number of extracellular enzymes, including several proteases , amylase, cellulase, and other degradative enzymes. Costs of exoprotein production can be estimated from material balances, molecular formulae, and growth parameters. Results of these calculations can be a key element in choosing a fermentor type and mode of operation for desired product formation. The functions included under strain development are identification and isolation of an organism exhibiting the trait (or traits) of interest; analysis and optimization of cultural conditions that allow expression of the trait; and mutagenesis, selection, and screening for isolates that hyperproduce the trait. In addition, overexpression of these proteins may improve the secretion efficiency of heterologous proteins, as has been demonstrated for signal peptidase.