Due to the depletion of fossil fuel and increase in the energy demand, there is a need for a renewable and sustainable source of energy. Lignocellulosic biomass is one of the renewable energy sources, which is able to reduce the greenhouse gas emission and a source of bio-based fuels and chemicals. Agriculture residue, food waste and non-edible crops are the sustainable source of the bio-based economy, which is also able to maintain the balanced economic growth. Lignocellulosic biomass contains mostly 40-50 % cellulose, 15-35 % hemicellulose and 10-30% of lignin. Lignin is the most abundant natural phenolic biopolymer on the earth. The global demand for aromatic compounds is also increasing because of their applications in pharmaceuticals, healthcare, paints and dyeing industry. Lignin, which is a major component of lignocellulosic biomass, is considered as a valuable source of phenolic and high value added aromatic compounds. It is also the main by-product of the paper-pulp and bio-ethanol industry. The present aim of the work is use of Sono-Fenton (non-conventional) method to depolymerize alkali lignin in the presence of alkaline medium. The process parameters like time, lignin concentration and ultrasound power were studied with an amount of Fenton reagent to maximize the phenolic yield and selectivity of the products. The second study aims towards the Lignin separation from carbohydrates, in the stable form from biomass then depolymerization of lignin into phenols under reductive environment. The Effects of different operating conditions like time, temperature were studied to increase the yield and selectivity of the products. The experimental details and results of work will be discussed during the presentation.