With the depletion of natural oil reserves, the need for alternative renewable
sources for energy and chemicals is growing. Waste biomass which is a side product of
some industries, can be used as feedstock to produce biofuels and other value-added
products. The main components of lignocellulosic biomass are cellulose, hemicellulose
and lignin. The valorisation of cellulose from biomass is an established process of
converting cellulose to simple sugars, which can be converted in further processing
operations. Commercial product of cellulose valorisation is bioethanol. Lignin
valorisation processes are still non-commercial and therefore less suitable for industrial
scale. In the future, biorefineries will focus on the co-valorisation of lignin and
cellulose. Another source of lignin could be the lignin that is a by-product of the paper
industry. This lignin is chemically modified, which should be taken into account when
designing valorisation processes. The valorisation of lignin could be steered in the
biological direction, where useful chemicals could be obtained by mimicking the
processes of biomass degradation in nature. White rot fungi and certain bacteria are
capable of just that. Through genetic modifications of certain bacteria, some scientists
have already found that it is possible to biologically funnel the conversion of several
substrates to a smaller number of end products. The challenge of the heterogeneous
structure of lignin is thus solved. Lignin valorisation products can be fuels, materials
and other value-added chemicals.
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