Exploring potential use of Australian thraustochytrids for the bioconversion of glycerol to omega-3 and carotenoids production

• Glycerol showed promising biomass growth with significant lipid and carotenoid productivity.
• A three-fold increase in carotenoid content in all isolates was achieved.
• Thraustochytrid isolates have astaxanthin or canthaxanthin as dominant carotenoids.
• DHA and carotenoids present in these isolates presents an opportunity to exploit them as potential bio-refinery systems.

Marine microbes have the potential for accumulating large quantities of lipids and are therefore suitable candidate as feedstock in unsaturated fatty acid production. The efficient utilisation of glycerol as an alternative carbon source to glucose was demonstrated in the fermentation of newly isolated thraustochytrid strains from the Queenscliff, Victoria, Australia. The isolates exhibited the presence of omega-3 and omega-6 polyunsaturated fatty acids, with the major fatty acids for all isolates being (as percent total fatty acid), palmitic acid (25.1–40.78%), stearic acid (4.24–13.2%), eicosapentaenoic acid EPA (2.31–8.5%) and docosapentaenoic acid (7.24–10.9%). Glycerol as a carbon source gave promising biomass growth with significant lipid and DHA productivity. An approximate three-fold increase in carotenoid content in all isolates was achieved when glycerol was used as a carbon source in the production medium.