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The valorisation of lignin is crucial in making lignocellulosic biorefining economically viable. Unfortunately, in conventional processes, such as Kraft pulping, the lignin is hard to convert into intermediates and end products because of unwanted components.
Editorial office / Rotterdam

Roberto Rinaldi (Imperial College) presented at Eco-Bio 2016, held in Rotterdam, parts of his research conducted in Germany and England. ‘In terms of mass and energy (content) lignin is an important macromolecule. It has the reputation of being ‘difficult’ which isn’t true. The complexity added to native lignin is due to the processing – Kraft pulping – of lignocellulosic biomass.’

The model of obtaining lignin therefore has to change, Rinaldi said. The idea is to ‘mine’ lignin first, not as a byproduct but as a main product. Through catalytic hydrogen transfer reactions, a new biorefining method results in the isolation of depolymerized lignin, a non-pyrolytic lignin bio-oil, in addition to pulps that are amenable to enzymatic hydrolysis. The oil doesn’t contain any acid species, just fenols, is stable in storage up until two years and relatively easy to convert into other end products. According to Rinaldi, there is a downside to the process, namely the production of CO2, which in some way needs to be mitigated.