Modelling strategies for the industrial exploitation of lactic acid bacteria

Key Points Lactic acid bacteria (LAB) have a long tradition of use in the food industry, and the number and diversity of their applications have increased considerably over the years. Industrial applications of LAB can be divided into three types on the basis of their specific optimization criteria: applications involving biomass production (starter cultures, probiotics), those involving bulk chemicals production (lactic acid, polyols) and those producing fine chemicals and functional ingredients (flavour compounds, exopolysaccharides, vitamins). Recent technological advances in the field of functional genomics have moved the focus from more traditional modelling techniques used in biotechnology to global modelling techniques. Genome-scale models and their analysis by constraint-based modelling specifically have attracted a lot of attention. Genome-scale models are a condensed inventory of the metabolic capacity of an organism, in which the metabolic reactions are coupled to the genes and their gene products. As such, these models can be used to integrate high-throughput data sets, such as transcriptomics and metabolomics data. Mapping of the global modelling techniques onto the industrial applications of LAB results in many possibilities for the use of these models in scanning process conditions and exploring the metabolic capabilities. However, it also becomes clear that this is only the first step towards strain improvement: for truly rational metabolic engineering, understanding of the control structure of the network will be essential. A major challenge for future work therefore lies in the incorporation of kinetic and regulatory information into the global metabolic models, so that the control structure can be derived and understood in terms of the interactions between all components in the cell. Lactic acid bacteria (LAB) are extensively used in the food and chemical industries. Here, Bas Teusink and Eddy Smid discuss how global metabolic modelling approaches, encompassing metabolic engineering, functional genomics and mathematical analysis, can be applied to optimize the industrial applications of LAB. Lactic acid bacteria (LAB) have a long tradition of use in the food industry, and the number and diversity of their applications has increased considerably over the years. Traditionally, process optimization for these applications involved both strain selection and trial and error. More recently, metabolic engineering has emerged as a discipline that