FED-BATCH FERMENTATION OF Escherichia coli FOR A PKS-DERIVED METHYLBRANCHED ESTER PRODUCTION

S. MENENDEZ-BRAVO; SABATINI M.; ROULET J.; COMBA S.; ARABOLAZA A.; GRAMAJO H.

Mar del Plata

Congreso; LI Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2015

Microbial fatty acid (FA)-derived molecules have emerged as promising alternatives to petroleum-based chemicalsfor reducing dependence on fossil hydrocarbons. In this sense, we have successfully engineered into Escherichia colia mycocerosic polyketide synthase-based biosynthetic pathway from Mycobacterium tuberculosis and redefined itsbiological role towards the production of multi-methyl-branched-esters (MBE) with novel chemical structures. In thiswork we aimed to develop a fed-batch fermentation process in order to increase MBE production yields. To achievethis goal we cultured the E. coli MBE producer strain in 1 L fermentors, using a glucose-based minimal media. Afteroptimization of medium composition and growth parameters for this particular strain, we focused our study ondetermining the optimal protein induction timing and inducer concentration, in order to maximize the volumetricproduction of the lipid product. After all of these steps, we scaled up the process to a 75 L fermentation. Finally, wedeveloped a protocol for MBE purification from total lipid extracts, based on the differential silica adsorption affinityof the MBE esters in comparison to the phospholipid and fatty acid fractions of the extract. After that, a silica columnbased purification of MBE led us to obtain the pure product, suitable for physicochemical properties measurements.