Scientists at the University of York are playing a key role in the quest for a better understanding of how a recently discovered family of enzymes can degrade hard-to-digest biomass into its constituent sugars.

The enzymes – lytic polysaccharide monooxygenases (LPMOs) – are secreted by both fungi and bacteria and have the ability to 'chip away' at cellulose and other intractable materials. This allows cellulosic materials such as plant stems, wood chips and cardboard waste, as well as other tricky materials such as insect/crustacean shells, to be broken down.

Finding a way of breaking down cellulosic materials into their constituent sugars is one key barrier to developing ‘second generation’ or ‘advanced’ biofuels, which could be made from crop by-products, algae or other material which would not compete with food production, as is the case with modern crop-based biofuels. Breaking down hard to digest materials in this way would allow them to be fermented into bioethanol.

Reporting this week as part of an international team of researchers, Professor Paul Walton and Professor Gideon Davies from York, provided important new information on how LPMOs work. The team – which included scientists from the United States, Denmark and the UK – carried out a detailed investigation of how the enzymes use oxygen from the air to create a very reactive entity. This oxygen species then chips away at cellulose, allowing the difficult-to-degrade biomass to be broken down.

The York research is part of a European initiative to create sustainable biofuels, as first generation fuels have been linked to negative environmental impacts, including deforestation and food price volatility. Some, especially vegetable-based fuels from crops including oilseed rape, may be just as polluting as their fossil fuel equivalents, once the effects of land-use change are factored in.   

Professor Walton said, "The ability to ferment cellulose is important as it opens up new possibilities in the production of bioethanol from sustainable sources. Through our collaborative research we are starting to uncover exactly the details of how LPMOs work."

The discovery of an important new family of LPMO able to break down hard-to-digest biomass, by researchers at York and Marseilles, could open the door to more sustainable fuel production.

Professor Davies said, "To begin fermenting materials such as wood chips or plant stems, there needs to be a way of breaking into it. The action of an LPMO makes a scratch on the biomass surface which provides an entry point for other enzymes. Understanding how LPMOs work will aid the quest for second generation biofuel production."