Production kinetics of conjugated fatty acids by lactic acid bacteria during in vitro fermentations

Recently, a lot of attention has been directed towards the health advantages of conjugated fatty acids (CFA), in particular the conjugated linoleic acids (CLA). CLA-isomers are naturally ocurring in tissues and products of ruminants, amongst others due to specific biohydrogenation and enzymatic activities of rumen bacteria (isomerases). Via directed feeding, ruminal metabolism can be directed towards higher CLA contents in the milk. Also, a number of lactic acid bacteria, bifidobacteria and propionic acid bacteria possess linoleic acid isomerases. As an alternative for interventions via the feed, bacterial generation of CLA in milk (via suitable microbial isomerase/desaturase activities) could be very interesting. If this approach appears to be successful, industrial use of these bacteria as starter cultures in the dairy industry can be envisaged. In this project, a number of computer-controlled laboratory fermentations will be carried out with selected microorganisms that are capable of producing such fatty acids. The production kinetics of fatty acid conversion will be studied in function of microbial population growth and the prevailing environmental conditions. A better understanding of their production kinetics will permit the application of such selected microorganisms in industrial fermentation processes in the dairy sector, enabling the production and commercialisation of new products with health-promoting properties.