Engineering Bacteria for Biofuel Production

Our research into biofuels addresses the need for environmentally and socially responsible sources of energy. Biofuels, made from organic matter, have recently become a viable alternative to petroleum-based fossil fuel. Sugar and starch make up the majority of feedstock used in biofuel production as it is easily digested. However, the use of these feedstocks is problematic as it consumes resources with negative environmental and social implications. By using a bacterium able to utilise five and six carbon sugars, such as the thermophile Geobacillus thermoglucosidasius, organic lignocellulosic waste material can be used as a feedstock.

The aim of this project is to investigate and utilise key genetic regulators of fermentation in G.thermoglucosidasius and to construct genetic engineering tools that enable strain development, for second generation biofuel production. We have focused on the redox-sensing transcriptional regulator Rex, widespread in Gram positive bacteria, which controls the major fermentation pathways in response to changes in the cellular NAD+/NADH ratio. Having identified several members of the Rex regulon, we are now building novel synthetic regulatory switches that can be used to dynamically control gene expression in response to changes in cellular redox state. In addition, new approaches and tools for the efficient genetic engineering of G.thermoglucosidasius will be discussed including an optimized E. coli - Geobacillus conjugation method for plasmid transfer and gene disruption.