This review focuses on the pivotal role of catalysis, both chemical and biological, in the development of sustainable technologies for the conversion of waste biomass to fuels, commodity chemicals and bio-based materials, such as bio-plastics, in a so-called bio-based, circular economy. Emphasis is placed on the catalytic conversion of second generation waste lignocellulosic biomass. (C) 2016. Elsevier B.V. All rights reserved.