1. Bioprocess, Environmental and Chemical Technologies Research Group, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK
2. Present address: Centre for Synthetic Biology and Innovation, Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
3. Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK