With concerns over the future of natural resources and energy security there is a growing need for the UK to develop renewable and sustainable sources of chemicals such as butanol, a key precursor in the production of paints, polymers and plastics. Bio-butanol can also be used as a biofuel, directly replacing gasoline or blended with diesel and with many advantages over ethanol. However in order for these bio-based chemicals to compete with oil derivatives we need to improve the range of cheap, sustainable feedstocks that can be fermented by solventogenic microbes, and the efficiency of this fermentation process. Current commercial processes require the use of extreme heat and harsh chemicals to convert agricultural waste material to simple fermentable sugars. This not only reduces the environmental benefits of renewables but also makes the fermentation of waste feedstocks less economic when compared with easier substrates such as starch. We are developing microbial strains that are able to use agricultural wastes that have undergone less intensive pre-treatment procedures to produce bio-butanol with high efficiency, thereby reducing the environmental impact of harsh chemical and high temperature processes and reducing the competition for food crops as fermentation substrates.