NOVELTY - Conversion of lignocellulosic materials to a liquid biofuel comprises a series of processing steps where feed materials are hydrolyzed in three stages and withdrawn as three product streams, each comprising solubilized fragments of one of the three major components of the feed materials; a set of concurrently operating processing steps where each of the three product streams is transformed through chemical or biochemical processes into products, such as pure lignin and ethanol that have a high calorific value; and combining the products with high calorific value to form a liquid biofuel.    USE - The process is for converting lignocellulosic materials to a liquid biofuel comprising a chemically modified form of lignin component dissolved in ethanol that is produced from cellulosic components. The lignocellulosic materials are field residues such as cotton stalks and corn stover, process residues such as sugarcane bagasse and sweet Sorghum bagasse, woody parts of energy crops such as switchgrass and Miscanthus, and forest residues or byproducts of wood processing industries such as sawdust from sawmills (claimed). The liquid biofuel is used as substitute for liquid fuels derived from petroleum crude. It is used for any purpose where there is a need for thermal energy by burning in the presence of air, e.g. an external combustion engine or stirling engine, and useful for moving vehicle powered by batteries, to recharge the batteries while in motion.    ADVANTAGE - The process increases the yield of energy contained in liquid biofuels produced from lignocellulosic materials, in a cost-effective and energy-efficient manner, by first isolating the lignin contained in the feed material in a chemically modified form that is soluble in the liquid fuels produced from the sugars contained in the feed material and through judicious selection and combination of processing steps, e.g. appropriate catalyst and catalyst recycling step, such that the only major inputs to the overall process are agrowaste biomass, water, and energy in the form of heat and electricity. It has sufficiently mild processing conditions, i.e. temperature and operating pressure in each processing step, to reduce the cost of steam and electricity required in these steps and the formation of degradation products having a deleterious effect on the operation of downstream process steps. The process, by greatly increasing the yield of energy contained in the liquid biofuels produced from lignocellulosic materials, lowers the cost per GJ of energy contained in the liquid biofuels both in terms of capital expenditures required for selling up the processing plants and the operating expenses incurred during the running of these plants. The lower cost liquid biofuel can be used as an economically competitive substitute for liquid fuels derived from petroleum crude. A further reduction in cost per GJ of the liquid biofuel is achieved due to the manner in which the process provides streams of pure components, lignin and cellulose, both of which can be in part processed further to much higher value products and the higher value realization used to offset some of the processing costs entailed for the production of liquid biofuels themselves. Considering the dwindling reserves of petroleum crude and the increasing atmospheric carbon dioxide levels caused by fossil fuel consumption, the energy content of agrowastes represents a very attractive renewable resource that can be utilized as raw material for the preparation of renewable liquid fuels. An economical, energy efficient, and environmentally benign process of converting lignocellulosic materials into liquid biofuels is achieved. The liquid biofuels have an energy content that is more than 70% of that of the solid agrowastes. The yield of the liquid biofuel is approximately 50 wt.%. The process cleanly regenerates the catalyst used in one of the hydrolysis steps and thus makes it possible to avoid the use of any major inputs, such as acids and bases, other than the agrowastes and water. The liquid biofuel has an energy content of approximately 30 MJ/kg, density of approximately 0.9 g/ml, kinematic viscosity of approximately 3 cSt, and very low sulfur and nitrogen content. It burns cleanly generating no visible soot; is stable as a liquid; and does not solidify even below 275 K. The overall yield of liquid biofuels could reach 16 wt.% of the weight of the primary crop.    DETAILED DESCRIPTION - Conversion of lignocellulosic materials to a liquid biofuel comprising a chemically modified form of lignin component dissolved in ethanol that is produced from cellulosic components, comprises a series of processing steps where feed materials are hydrolyzed in three stages and withdrawn as three product streams, each comprising solubilized fragments of one of the three major components of the feed materials; a set of concurrently operating processing steps where each of the three product streams is transformed through chemical or biochemical processes into products, such as pure lignin and ethanol that have a high calorific value; and combining the products with high calorific value to form a liquid biofuel.