Production of organic acids by fermentation of Syngas

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The aim of this project is to evaluate the feasibility of producing platform chemicals by the fermentation of Syngas. The release of sugars from lignocellulosic biomass is still hindered by high enzyme cost and generation of inhibitors during processing. Upstream processes need to be customised for different biomass sources. Furthermore, some microorganisms, notably Saccharomyces cerevisiae, can only utilise effectively C6 sugars and not the C5 sugars that make up a significant proportion of the total carbohydrate. An alternative approach is gasification of the biomass to generate Syngas (carbon monoxide and hydrogen) which can act as a growth substrate for carboxydotrophic (CO-utilising) microorganisms. Gasification can be applied to all different biomass sources and even lower grade materials such as municipal wastes. Furthermore all of the carbon is released for fermentation, even the lignin component which is not available from other processing options. Unfortunately carboxydotrophs are not as well-studied as sugar fermenting heterotrophs and appear naturally to produce only a restricted range of products such as acetate and ethanol. This project aims to break new ground by evaluating the potential to use metabolic engineering to broaden the range of products from fermentation of CO to include valuable platform chemicals.