Engineering lactococci for increased functionality

Various strategies have been employed to engineer lactic acid bacteria (LAB) to improve their functionality as cell-factory or in food fermentation applications. Lactococcus lactis has long served as a paradigm organism in genetic engineering of the LAB, and the analysis of gene-specific mutant strains and/or strains overexpressing specific functions has been crucial for our increased insight in gene-regulation and metabolism of these industrially important microbes. However, application of engineered strains in food fermentations is limited by the lack of consumer acceptance of genetically engineered foods. This has led to a renewed interest in natural mechanisms of gene transfer and has stimulated the use of experimental evolution to increase specific LAB functionalities