Austrian scientists have shown that an environmentally friendly enzyme, laccase, can be used to replace toxic drying agents in paint.
Currently, water-based paints contain heavy metals that dry the alkyd (polyester) resin films that are used as binding agents by catalysing the oxidative cross-linking of unsaturated fatty acid moieties in the films. Heavy metals are often toxic, and the commonly used cobalt-based catalysts have recently proved to be carcinogenic, and so alternative materials are being sought.
Enrique Herrero Acero at the Austrian Centre of Industrial Biotechnology, Graz, and colleagues, decided to replace the heavy metal catalysts with a laccase enzyme–mediator-based, non-toxic biocatalyst. Laccases, found in fungi, bacteria and plants, can catalyse the oxidation of mainly phenolic substances, and are already used in other fields, including the food, pulp and paper, and textile industries.
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Banning toxic heavy-metal catalysts from paints: enzymatic cross-linking of alkyd resins
Katrin J. Greimel, Veronika Perz, Klaus Koren, Roland Feola, Armin Temel, Christian Sohar, Enrique Herrero Acero, Ingo Klimant and Georg M. Guebitz
Green Chem., 2013, Advance Article
DOI: 10.1039/C2GC36666E