Supercritical extraction of waxes and lipids from biomass : A valuable first step towards an integrated biorefinery

The decline in petrochemical wax supply coupled with the ever-growing demand for bio-products means that the development of a sustainable process to renewably sourced waxes is paramount. This review focuses on recent advances in supercritical extraction as a clean efficient process for extracting waxes from waste biomass as a part of a holistic biorefinery. The use of supercritical carbon dioxide leads to reductions in solvent waste and leaves no solvent residues meaning that the biomass can further processed without the need for energy-intensive solvent removal steps. This technology crucially improves the downstream conversion of residual cellulosic biomass for the sustainable production of sugars, consumer products and biofuels (up to a 40% increase in ethanol production) leading to higher energy efficiencies and higher economic returns. Supercritical carbon dioxide extraction is not only an important technology for the cleaner production of waxes, it is a sustainable pre-treatment of biomass as part of an integrated holistic biorefinery and significantly, it can improve the safety of products, e.g. less off gassing of wood pellets.