Investigation of the Molecular Weight Increase of Commercial Lignosulfonates by Laccase Catalysis

• Published in: Biomacromolecules Vol. 11; no. 4; pp. 904 - 910
• Main Authors: Areskogh, Dimitri, Li, Jiebing, Gellerstedt, Göran, Henriksson, Gunnar
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 12.04.2010
• Subjects: Applied sciences; biosynthesis; Catalysis; Chemistry; Chromatography, Gel; delignification; Exact sciences and technology; Kemi; Laccase - metabolism; lignin; Lignin - analogs & derivatives; Lignin - chemistry; Lignin - metabolism; Lignin and derivatives; Molecular Weight; Natural polymers; NATURAL SCIENCES; NATURVETENSKAP; Organic chemistry; Organisk kemi; oxidation; Oxidation-Reduction; Physicochemistry of polymers; Polymer chemistry; Polymerkemi; pulp; Spectroscopy, Fourier Transform Infrared; spruce wood; Enzymatic treatment; Enzyme; Time curve; Oxidation; Oxidoreductases; Experimental study; Molecular mass; Lignosulfonate; Optimization; Operating conditions; Laccase
• ISSN: 1525-7797; 1526-4602; 1526-4602
• DOI: 10.1021/bm901258v

Lignosulfonates are by-products from the sulfite pulping process. During this process, lignin is liberated from pulp fibers through sulfonation and washed away. As a consequence, the lignosulfonate molecules contain both hydrophobic and hydrophilic moieties. Lignosulfonates are low-value products with limited performance and are used as such as binders, surfactants, and plasticizers in concrete. Lignosulfonates face strong competition from synthetic petroleum-based plasticizers with superior quality. Therefore, increasing the performance of lignosulfonates is desirable not only from a sustainability point of view but also to expand their usage. One important aspect that describes how well lignosulfonates can act as plasticizers is the molecular weight. In this paper, the molecular weight of four commercial lignosulfonates is increased through oxidation by two laccases without utilization of mediators. Different parameters to obtain maximal molecular weight increase were identified and the technical significance of the experiments is discussed.