Long chain polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA, C22:6) are essential in eukaryotes as components of cellular membranes and signaling processes.  Interest in this area has been increasing due to clinical evidence of the importance of PUFAs in human health, development and nutrition.  PUFAs also have important functions as components of membranes and precursors of biological effector and signaling molecules including those involved in inflammatory responses.

One pathway for the biosynthesis of PUFAs relies on the step-wise, alternating action of desaturases and elongases on shorter-chain fatty acid substrates.  Alternatively, organisms such as the marine microalga Schizochytrium sp. and some marine bacteria produce PUFAs via an independent PUFA synthase.  While the overall architecture of these polyketide-like synthases differs from both fatty acid and polyketide synthases, they do contain domains and biosynthetic mechanisms common to both of those systems.  Fatty acid and polyketide biosynthesis have been well studied but PUFA synthases have been relativity unexplored.  Data concerning various aspects of the biosynthesis of PUFAs will be presented.

The independence of PUFA synthases from the standard fatty acid synthesis pathways and the relatively pure end-products has made them attractive targets for heterologous expression.   Data related to PUFA production in heterologous hosts using PUFA synthase gene systems will also be presented.