Burning fossil fuels is a major source of greenhouse gas emissions and replacing these with truly sustainable biofuels in which the released carbon is balanced by photosynthetic fixation into new biomass is an important way to reduce emissions. Producing biofuels from crops is unsustainable in terms of global food security and instead we need to focus on waste sources of biomass. The UK is a net importer of food and other biomass such as paper and wood, and every year more than 50 Mt of biological material in the form of municipal and commercial waste is sent to landfill at high cost to the environment and economy. This biological fraction of solid waste (BioSW) represents the biggest untapped source of biomass available in the UK that could be used for biofuel and biochemical production (1). With landfill taxes in excess of £100/t, solid waste comes with an equivalent gate fee, which translates to a BioSW feedstock cost in the region of minus £40/t. This compares very favourably with alternative biomass sources such as cereal straw, of which only 5-10 Mt are available in the UK and which is currently priced at around £60/t).

The studentship project involves a close collaboration between an innovative engineering company, Wilson Steam Engineering, and the McQueen-Mason research group in the Centre for Novel Agricultural Products at York. Wilson Steam has developed waste autoclave technology that allows unsorted MSW to be sterilised and separated into recyclable metals, glass and plastics leaving a solid (fibre) component that has a high (40% of dry matter) polysaccharide (mostly cellulose) content that currently has little use. The McQueen-Mason group has a strong track record in underpinning research for the development of sustainable biofuels from woody biomass (2-4). Preliminary work has shown the feasibility of cleaning the autoclave fibre and using it as a potential substrate for hydrolysis and fermentation to establish the basis of a sustainable renewable biofuel that could displace petroleum derived fuels. However, a number of technical challenges need to be tackled before fuels produced in this way become a reality.