Systems biology of lactic acid bacteria: For food and thought

Abstract

Lactic acid bacteria (LAB) ferment plants, fish, meats and milk and turn them into tasty food products with increased shelf life; other LAB help digesting food and create a healthy environment in the intestine. The economic and societal importance of these relatively simple and small bacteria is immense. In this review we hope to show that their adaptations to nutrient-rich environments provides fascinating and often puzzling behaviours that give rise to many fundamental evolutionary biological questions in need of a systems biology approach. We will provide examples of such questions, compare the (metabolic) behaviour of LAB to that of other model organisms, and provide the latest insights, if available.

Keywords: Biotechnology; Food fermentation; Lactic acid bacteria; Lactobacillus; Lactococcus; Systems biology.

Figure 1

Fermentation pathways in L. lactis to lactate or mixed acid fermentation. (A) Overview of the biochemical reactions, with external metabolites in white boxes, lumped metabolite pools in grey boxes, and positive (green) and negative (red) regulation by F16bP. (B) Is the metabolic regulation of acetate versus lactate observed in the chemostat (lower figure, based on [33]) a series of still pictures from a normally fast transition to glucose depletion (upper figure, based on [34])? During a brief period of glucose depletion, growth rate decreases rapidly, and a shift of lactate towards acetate production takes place.