Collaborative Research: A Systems Biology Approach for Metabolically Engineering Escherichia coli for Producing Hydrogen via Fermentation

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CBET-0753664SrivastavaNon-harmful bacteria may be used to produce chemicals for humans and this includes fuels. Molecular hydrogen is an environmentally-clean fuel; hence, if hydrogen can be synthesized efficiently by bacteria, then we may reduce air pollution, reduce our dependence on foreign oil, and avoid greenhouse gases (the carbon dioxide formed by our process will be recycled to plant mass and used again to form hydrogen so there are no net emissions). This research will enable hydrogen to be produced as a clean form of energy from bacteria using fermentation of simple sugars. In fermentative production of hydrogen, glucose is converted into pyruvate which is converted to formate which is then converted to hydrogen. Hence, it is imperative to direct the carbon flux in the bacterial cell to hydrogen formation by preventing competing glucose reactions and those that convert pyruvate to acetate, lactate, and ethanol or that remove formate. To achieve this aim, a systems biology approach will be used to produce more hydrogen that includes (i) altering the metabolism of the bacteria by removing unwanted pathways, (ii) evolving the necessary enzymes using protein engineering, and (iii) modeling all the metabolic pathways of the bacterial cell so that even better bacteria may be generated. We have chosen Escherichia coli as our model system since (i) all 3985 non-lethal single mutations of strain E. coli BW25113 are available; (ii) we may combine mutations rapidly using our novel, successive, virus-based method; (iii) E. coli is the best-studied bacterium so its metabolism is well understood; and (iv) its genome is sequenced so DNA microarrays are available and metabolic flux analysis may be carried out at the genome-scale. Along with the research results, the three professors involved in this research will train undergraduate and graduate students, will make accessible, via the World-Wide Web, specific outcomes of the project, and will disseminate some of the research results to a diverse audience using podcasting.