In 2012, the World Economic Forum voted a new form of engineering the second most important new technology for economic growth. Synthetic biology creates new biological systems that could be used in the 'bioeconomy' – the sustainable production and conversion of biomass into a range of food, health, fibre and industrial products and energy. Professor Paul Freemont (Head of the Section of Structural Biology in the Department of Medicine) discusses why synthetic biology is becoming so vital for making new medicines, clearing pollution and even generating new fuels.