10/09/2009
Breaking Down the Steps of Plant Cell Wall Lignin Degradation
The Science
The scientific community needs to understand the biological mechanisms for cleaving the plant wall component lignin to develop new strategies for producing biofuels from lignocellulosic biomass. Researchers from the Forest Products Laboratory at the University of Wisconsin have shown how different unsaturated fatty acids assist a peroxidase enzyme in lignin breakdown. Some peroxidases from wood-decay fungi can cleave the major recalcitrant structures in lignin, but these reactions require the participation of low molecular weight mediators that apparently act as diffusible free radical oxidants. The new results show that the major unsaturated fatty acid produced by the fungi, linoleic acid, is also the most effective mediator for breakdown of lignin. The results also suggest that the initial peroxyl radicals formed may not be the ligninolytic oxidants in this system. Instead, other radical oxidants produced during late-stage reactions of lipid peroxidation may be required. Future experiments will examine the effectiveness of lignocellulosic degradation using peroxidases by including linoleic acid or linoleate esters in the formulations.
References
Kapich, A. N., R. V. Korneichik, A. Hatakka, and K. E. Hammel. 2009. “Oxidizability of Unsaturated Fatty Acids and of a Non-Phenolic Lignin Structure in the Manganese Peroxidase-Dependent Lipid Peroxidation System,” Enzyme & Microbial Technology 46, 136-40. DOI:10.1016/j.enzmictec.2009.09.014.