IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Microbial engineering for production of novel lipids
Autor/es:
SIMÓN MENENDEZ-BRAVO, SANTIAGO COMBA, ANA ARABOLAZA AND HUGO GRAMAJO.
Reunión:
Congreso; IX Congreso de Microbiología General; 2013
Resumen:
Nowadays, there are considerable
environmental and economic drivers that impulse the development of new and
improved bio-based chemicals. Particularly, in view of the lubricant industry,
vegetable oils (i.e. triacylglycerols, TAGs) are considered a good source of biolubricants.
However, their main disadvantages are their poor low temperature fluidity behaviour
and their sensitivity to oxidation at high temperatures. Wax esters have lubrication properties
that are superior to ordinary vegetable oil due to their high oxidation
stabilities and resistance to hydrolysis. Nevertheless, due to the high cost of
obtaining wax esters from existing sources, their use is limited to specialized
and high value product areas such as cosmetic, pharmaceutical and/or specialty
lubricants.
In this context, microbial-cell-factories
are an attractive model for the production of specific products as it provides
the opportunity to convert sustainable biomass into high value chemicals. The
assembly of metabolic activities derived from different organisms allows the reconstitution
of designed biosynthetic pathways for the production of novel molecules with chosen
features.
With
the aim of producing novel lipids with improved lubricant properties, we
propose the synthesis of multi methyl-branched wax esters (MMWEs) in Escherichia coli. The inclusion of
methyl branches would disrupt the lipid packing ability of the hydrocarbon
chains, thereby reducing the melting temperature of the oil without altering
chemical stability. To accomplish this, we
took advantage of the metabolic pathways involved in the biosynthesis of complex
lipids in mycobacteria. We have assembled a minimal set of three enzymes based
on a type I iterative polyketide synthase biochemistry for in vivo production of a variety of functionalized lipids in a
genetically improved E. coli strain. The
successful in vivo synthesis of MMWEs
by recombinant E. coli was detected
by thin layer chromatography and confirmed by HPLC coupled to nanospray tandem mass
spectrometry. We also showed that the chemical diversity of the MMWEs
produced can be modulated in function of the substrates utilized.