Lignin degradation and oxygen dependence

Abstract: This work concerns itself with the biological degradation of the lignin polymer. The chemical composition of the polymer makes it recalcitrant toward hydrolysis and other common chemical reactions occurring under biological conditions. The rumen of animals is considered as a place of high turnover rates for plant matter where lignin is an integral constituent. This makes it a promising place to look for microorganisms adapted to degrade the lignin fraction of the plant matter. In this work, steps were taken to create a metagenomic library of the microorganisms present in the rumen of sheep. Bioinformatical searches were performed to investigate the possible existence of enzyme systems explaining the widespread presence of the genera Clostridium and Desulfovibrio in environments rich in lignin. While several species of Clostridium contained an O-demethylase system, the presence of Desulfovibrio could not be explained.