Chapter 9 - Genetics of Lactic Acid Bacteria

Abstract

Our accumulated knowledge of the group of microorganisms known as the lactic acid bacteria (LAB), which harbor most of today’s widely used dairy starters, has expanded in an unprecedented manner in the past two decades. Application of high-throughput whole genome sequencing and the associated “omics” technologies have completely revolutionized the study of this important group of organisms, from providing a comprehensive view of the remarkable diversity within the group to the development of improved or novel strains and their associated processes in industrial application. Comparative and functional genome analysis of multiple LAB species and strains has not only given us new insights into the complete genetic potential of these organisms, but has also revealed a central trend in LAB evolution: the loss of ancestral genes and metabolic simplification toward adaptation to nutrition-rich environments. Pangenomics has offered the opportunity to acquire an in-depth understanding of the taxonomical and functional diversity within different species and genera, while systems biology approaches provide the means to a more holistic view of the metabolic potential of the group. In this chapter, we provide an overview of the developments in LAB research during this genomic era, particularly in relation to members of the group that are at the core of the dairy industry. We examine the genetic events responsible for the adaptation of these organisms to the specialized dairy environment, review new information on their metabolic potential afforded by genomic investigations, and examine the possibilities for exploitation of their metabolic potential, thus improving their use in biotechnological and health-related applications.