Disclosed is a method of changing a molecular structure of a biomass feedstock, the method comprising: preparing the biomass feedstock by reducing one or more dimensions of individual pieces of biomass； pre-treating the biomass feedstock using two or more different pre-treatment methods that each change the molecular structure, wherein the different pre-treatment methods are selected from radiation, sonication, pyrolysis, and oxidation； and processing the prepared and pre-treated biomass feedstock to produce a product.
