Metabolic Fluxes in Lactic Acid Bacteria-A Review

The technological role of lactic acid bacteria (LAB) has consistently increased in the recent decades. This is due to its large cellular production capabilities of metabolites with commercial interest and to its innocuous and beneficial characteristic of being considered generally regarded as safe (GRAS) and food tradition found virtually in all food categories. With the advent of the 21st century and Omics technologies, it has been possible for LAB to become metabolite overproducers, delivery vectors, and live vaccines, as well as improve in-situ technological properties, among many other applications. The present review offers an introduction to the LAB metabolism, showing that the main products are able to be secreted and diverted toward a specific molecule of value for bioproduction by directing the flux of pyruvate. Thus, a general overview of the metabolic flux analysis, isotopic techniques, and software calculations including examples in LAB is presented. Furthermore, flux distribution of the metabolic pathways in LAB enables the evaluation of the metabolic state and provides useful answers to improve target productivity in food, medical and industrial applications. It is clear that with the advances in genomics (more than 200 whole genome sequences) LAB will play a key role in the generation of environmentally friendly new bio-products, functional foods, biomaterials, and therapeutics products in the era of systems biology.