AVT - Research - Research project

In the last decades biomass has gained increasing importance as a renewable resource for fuels and platform chemicals. Especially wooden biomass has come under scrutiny, because there is no direct competition with food production. Rather unused parts of cereals like haulms and husk could be exploited in order to enlarge the range of application of plants and to increase the areic yield of agricultural cultivations. In average wooden biomass consists to approximately 95% of the polymers cellulose, hemicellulose and lignin.

Lignin is a heterogeneous, branched polymer derived from the three monolignols p-coumaryl, coniferyl, and sinapyl alcohol. It is located in the cell wall of higher plants and provides stability and protection against biodegradation and environmental stresses. Lignin is one of the most abundant renewable raw materials available on earth. Pulp and paper industry already produces millions of tons as a widely unutilized side product.

Both, the high availability and the content of phenolic subunits, feature lignin as an attractive resource to obtain platform chemicals which nowadays are only generated by petrochemical processes. The big challenge here is to break down the lignin polymer into its monolignolic subunits which then can be employed for further transformations to value-adding products of chemical and pharmaceutical industry. Furthermore a delignification of wooden biomass can improve the access to the other main components cellulose and hemicellulose.

In nature, lignin degradation occurs during the rot of biomass. Several saprophytes, especially from the fungi kingdom, are able to break down lignin. Their strategies for lignin utilization are based on certain enzymes, which catalyses the depolymerisation of the lignin molecule. The most prominent lignin degrading enzymes belong to the laccase family. Laccases catalyse a four electron transfer from a substrate over a mediator to oxygen which is reduced to water.

Within this project, a suitable reaction environment for laccase-catalysed lignin degradation shall be identified. This includes kinetic characterization of the laccase-mediator-system under various conditions. The obtained results shall help to draft an adapted process concept and a convenient reactor design.