17^th Euro Biotechnology Congress

Biography

Biography: David Bolonio

Abstract

Advanced biodiesel is an alternative fuel prepared from renewable non-food sources of biomass. It is non-toxic, non-flammable, biodegradable, and compatible with current vehicles and infrastructure. Most efforts to develop advanced biodiesel have focused on the metabolic engineering of microorganisms able to efficiently convert lignocellulosic and waste biomass into fuel molecules. The enterobacterial, Escherichia coli is well suited for this purpose owing to its exceptional amenability for genetic manipulation. Indeed, it has already been used for commercial synthesis of a wide array of chemicals. This work addresses two key steps for biodiesel production in E. coli: (i) increasing the total yields of free fatty acids (FAA) and (ii) improving FAA length and unsaturation from an applied standpoint. These properties must be carefully optimized in order to obtain optimum engine performance once FAAs are converted into esters or biodiesel. To this end, E. coli cells were genetically modified to express in an inducible fashion, a leaderless version of the enzyme thioesterase I (tesA), which cleaves the fatty acyl-carrier protein and deregulates the tight product inhibition typical of fatty acid synthesis, the transcription factor FadR, which down-regulates several genes in the fatty acid degradation pathway and increases fatty acid unsaturation; and a plant acyl-ACP thioesterase (FatA) showing higher hydrolytic activity towards oleoyl-ACP than the endogenous bacterial enzyme. As a result of the above manipulations we report here a 6-fold increase in FAA yield and a significant improvement of one of the most important properties of biodiesel: the cold flow performance.