Evolutionary Genomics of Lactic Acid Bacteria

The lactic acid bacteria (LAB) might be the most numerous group of bacteria linked to humans. They are naturally asso- ciated with mucosal surfaces, particularly the gastrointestinal tract, and are also indigenous to food-related habitats, includ- ing plant (fruits, vegetables, and cereal grains), wine, milk, and meat environments (60, 61). The LAB include both important pathogens, e.g., several Streptococcus species, and extremely valuable nonpathogenic species that are used for industrial fermentation of dairy products, meats, and vegetables, and they are also critical for the production of wine, coffee, silage, cocoa, and sourdough (13, 60, 61). In addition, the LAB are a priceless source of antimicrobial agents, the bacteriocins (ref- erence 10 and references therein). The term LAB mainly refers to the defining feature of the basal metabolism of these bacteria, the fermentation of hexose sugars yielding, primarily, lactic acid. Various aspects of LAB biology and application are thoroughly covered in several books by Wood and Holzapfel and Wood and Warner (60, 61)