Metabolic Engineering Approach for Advanced Microbial Fuel Production Using Escherichia coli

Abstract

AbstractCurrently, biodiesel (fatty acid alkyl ester, FAAE) and bioethanol are two major candidates with great commercial importance concerning biofuel industries. Ethanol is the most extensively produced, utilised and collective with biodiesel accounting for 90% of the biofuels market. Fatty acid alkyl ester is synthesised during the transesterification of triacylglycerols obtained from plant-derived material. The major hurdles for the transesterification process are the use of toxic methanol, various cereal/oil crops, agricultural land and higher energy consumption. Hence, the production of free fatty acid-derived biofuels via microbial fermentation is a great strategy to overcome the hurdles. For the fatty acid synthesis, Escherichia coli has been demonstrated as a model bacterium due to its higher growth rate, has been well studied concerning metabolic engineering and has been an industrially important microorganism. Several sets of enzymes are engaged in fatty acid biosynthesis, membrane synthesis and fatty acid degradation. By overexpression and deletion of the respective genes, the higher production of free fatty acid (FFA) and biofuel intermediates can be possible in any industrially important strain. Specific strategies such as transcriptional regulation, promoters of the Fab operon, regulation by stringent response and remodelling of the FFA biochemical pathway can be used to exploit the production of biodiesel.KeywordsEngineered E. coliMicrobial fuelsFree fatty acidsFatty acid allyl esterFab operonShort-chain alcohols