Processing of a reaction product mixture of cellulosic biomass material containing at least one volatile organic compound at least one of lignin, a lignin-derived compound, unextracted cellulose, unextracted hemicellulose, a caramelan, and any combination thereof by vaporizing the at least one volatile organic compound using at least thermal energy generated by combusting at least a portion of the reaction product mixture. In a particular embodiment, the reaction product mixture comes from reactions involving deconstruction (or digestion) of cellulosic biomass which contains various polysaccharides (e.g., carbohydrates) and lignin.