A review on lignin utilization in petroleum exploration, petroleum products formulation, bio-fuel production, and oil spill clean-up

After cellulose, lignin is considered to be the most abundant, renewable, economical natural biopolymer existing on earth. Out of the natural biosynthesized carbon in biosphere, lignin accounts for 30%. Lignin is a complex aromatic polymer and a vital cell wall structural component. This highly complex phenolic macromolecule is obtained as a low-value by-product of cellulose production and by the paper pulp industry. It is an underutilized material, so the use of lignocellulosic feedstock is increasing as a renewable and sustainable alternative to petroleum resource. Several efforts have also been made to use lignin in the petroleum field. Here, we summarize the current knowledge regarding lignin utilization for the petroleum exploration, petroleum products formulation, bio-fuel production, and oil spill clean-up. This review covers the direct use of lignin (as such) and also the chemical modifications of lignin. The future perspective and trend towards lignin-based material utility for the petroleum industry are then addressed.