What is Lignin

Lignin is the second most abundant natural polymeric carbon source on earth after cellulose. It is a plant-originated polymer with three-dimensional network of dimethoxylated (syringyl), monomethoxylated (guaiacyl), and non-methoxylated (phydroxyphenyl) phenylpropanoid and acetylated units. The structural complexity and insolubility of lignin make it highly recalcitrant for degradation. Its biological degradation is critical to the global carbon cycle. Bioligninolysis involves application of microorganisms and their enzymes in degradation of lignin whichprovide environmental friendly technology for various industrial applications. As a major repository of aromatic chemical structures, lignin bears paramount significance for its removal from woody plants/lignocellulosic material, owing to potential application of bioligninolytic systems on commercial scale. This chapter provides an overview of microbial ligninolysis and its role in carbon cycling, various industrial process and pollution abatement for natural ecosystem management.