Many
Bacillus species are able to
secrete large quantities of enzymes.
Bacillus amyloliquefaciens is the source of a natural antibiotic protein
barnase (a
ribonuclease),
alpha amylase used in starch hydrolysis, the
protease subtilisin used with detergents, and the
BamH1 restriction enzyme used in DNA research. A portion of the
Bacillus thuringiensis genome was incorporated into
corn and
cotton crops. The resulting plants are resistant to some insect pests.
Bacillus subtilis (
natto) is the key microbial participant in the ongoing production of the soya-based traditional natto fermentation, and some
Bacillus species are on the Food and Drug Administration's GRAS (generally regarded as safe) list. The capacity of selected
Bacillus strains to produce and secrete large quantities (20–25 g/L) of extracellular enzymes has placed them among the most important industrial enzyme producers. The ability of different species to ferment in the acid, neutral, and alkaline pH ranges, combined with the presence of thermophiles in the genus, has led to the development of a variety of new commercial enzyme products with the desired temperature, pH activity, and stability properties to address a variety of specific applications. Classical mutation and (or) selection techniques, together with advanced cloning and protein engineering strategies, have been exploited to develop these products. Efforts to produce and secrete high yields of foreign recombinant proteins in
Bacillus hosts initially appeared to be hampered by the degradation of the products by the host proteases. Recent studies have revealed that the slow folding of heterologous proteins at the membrane-cell wall interface of Gram-positive bacteria renders them vulnerable to attack by wall-associated proteases. In addition, the presence of thiol-disulphide oxidoreductases in
B. subtilis may be beneficial in the secretion of disulphide-bond-containing proteins. Such developments from our understanding of the complex protein translocation machinery of Gram-positive bacteria should allow the resolution of current secretion challenges and make
Bacillus species preeminent hosts for heterologous protein production.
Bacillus strains have also been developed and engineered as industrial producers of nucleotides, the vitamin riboflavin, the flavor agent ribose, and the supplement poly-gamma-glutamic acid. With the recent characterization of the genome of
B. subtilis 168 and of some related strains,
Bacillus species are poised to become the preferred hosts for the production of many new and improved products as we move through the genomic and proteomic era. ==Use as model organism==