New/improved lignin products

Dimitri Areskogh

Ph.D. Student: Dimitri Areskogh
E-mail: d.areskogh@polymer.kth.se

Objectives:

The aim of this project is to investigate how the biodegrading enzyme laccase (multi-copper containing oxidase, E.C. 1.10.3.1) can be used on technical lignosulfonates to obtain new or improved lignin-based products with specific properties.

Lignosulfonates are the byproducts from the sulfite pulping process in the papermaking industry. These sulfonated lignins possess unique properties. The presence of both hydrophobic phenyl propane moieties as well as strong hydrophilic sulfonic groups ensures their good surfactancy and dispersibility which is desirable in a large number of applications such as concrete plasticizers or deflocculant in cement industry.

Activities:

Several approaches are pursued to solve the objectives. One of them is to gain a more comprehensive understanding of the action of laccase) on simple lignin model compounds and on technical lignin samples such as lignosulfonates. This includes an overview of the reaction mechanism of laccases. Another approach is quantifying the phenolic content, increasing it and oxidizing phenols to achieve increased hydrophilicity. The third main approach is to control molecular weight distribution of industrial lignosulfonates by laccase treatment.