Biotechnological production of conjugated fatty acids with biological properties

Conjugated derivatives of fatty acids, namely conjugated linoleic acid (CLA) and conjugated α-linolenic acid (CLNA), have attracted much attention of the scientific community over the last two decades due to their biological properties. In fact, several studies realized in animal models and/or cell cultures have shown anticarcinogenic, antiobesity, antiatherogenic, antidiabetic, and immunomodulatory activities. CLA and CLNA isomers are commonly present in ruminant's derived foods mainly because of the action of microorganisms on linoleic acid (LA) and α-linolenic acid (LNA), respectively. However, the natural concentrations of CLA and CLNA found in these food products do not seem to be sufficient to have any significant therapeutic effect and thus there are efforts to obtain CLA- and/or CLNA-enriched foods. Several food-grade microorganisms, such as bifidobacteria, lactic acid bacteria (LAB), and propionibacteria, are capable of producing CLA and CLNA from LA and LNA, respectively, given their linoleate isomerase activity. These microorganisms could thus be used to produce CLA-enriched foods either as starter or adjunct cultures or as biocatalysts producing CLA and/or CLNA that can be used as natural food additives. This chapter presents a comprehensive outlook of the biotechnological production of CLA and CLNA and a discussion of its technical issues, limitations, challenges, and potential food and nutraceutical applications based on nutritional value and biological properties.