Production of Bioactivity Secondary Metabolites by Cell and Tissue Cultures of Marine Seaweeds in Bioreactor Systems

Secondary Metabolite Biosynthesis

We are studying secondary metabolite biosynthesis in cell and tissue cultures of marine macroalgae, with emphasis on pathways that generate unique bioactive compounds. Efforts focus on two model systems. The first model system is the biosynthesis of C18 and C20 hydroxy fatty acids in female gametophyte cell cultures of the temperate brown alga Laminaria saccharina. In this system, linoleic acid is the common precursor. Linoleic acid is converted to C18 and C20 polyunsaturated and hydroxy fatty acids by a series of desaturation, elongation, and oxidation steps via w-6 lipoxygenase enzyme.

The second model system is the biosynthesis of cyclic and acyclic halogenated monoterpenes in the microplantlet tissue cultures of the tropical red algae Ochtodes secundiramea and Portieria hornemannii. In this system, geranyl diphosphate (GPP) from the nonmelavonate pathway is the common precursor. GPP is converted to myrcene, a monoterpene, by a novel myrcene synthase. Myrcene then undergoes a series of bromonium ion (Br+) mediated halogenation reactions to yield a variety of brominated and chlorinated monoterpenes.