Production of biodiesel using Mucor circinelloides

The foreseeable depletion of petroleum, along with the need of cleaner fuels is promoting the development of renewable alternatives, such as biodiesel. Although biodiesel is currently obtained by transesterification of plant oils, all studies rule out the possibility of generating all biodiesel needed in the future exclusively from these oils, due to the huge requirements of soil and water. This has led to suggest the use of lipid from both autotrophic (algae) and heterotrophic (fungi) oleaginous microorganisms as feedstock for biodiesel production. In the case of heterotrophs, they would be grown using industrial or agricultural wastes, improving their use and reducing environmental problems associated with them. The high lipid content and growth rate of Mucor circinelloides make it a suitable candidate for its use in the production of biodiesel.

Our research group aims to use genetic manipulation tools we have developed for Mucor, together with information derived from its genome sequence, to generate strains for their use by the industry in the production of biodiesel. Our early research, carried out in collaboration with the group of Dr. Gemma Vicente (Universidad Rey Juan Carlos, Madrid), has shown that Mucor lipids can be transformed directly without prior extraction into high-quality biodiesel that complies with European and American specifications. Recently, we have generated genetically engineered strains with high levels of malic enzyme, a key enzyme in the synthesis of lipids. Although these strains do not accumulate higher levels of lipids than the parental strain, they will be useful as parental strains in the generation of new improved strains. In parallel, we are performing genetic screenings to isolate mutants with high levels of lipids, and transcriptomic analysis to identify genes involved in the regulation of lipid biosynthesis and accumulation.