TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Device: In the biorefinery, the bio-product is a fuel comprised of the lignin and the lignin solvent exiting the pulper; or fuel comprised of the lignin and the lignin solvent exiting the pulper and biodiesel. The biorefinery further comprises a separator (40) for removing water from the mixture of lignin and lignin solvent exiting the pulper; and a pre-treater (14) operable to remove hemicelluloses from the plant fiber materials prior to passing the plant fiber materials to the pulper. The fermentation unit comprises: a depolymerization treatment unit (30) to reduce the polymer length of the cellulose from the pulper; a saccharification unit (34) to convert the portion of the cellulose and enzymes from the depolymerization treatment to sugars; and a fermenter to convert the sugars from the saccharification unit into the bio-product.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The lignin solvent is a hydrophobic solvent. The second bio-product is the lignin solvent (preferably methyl butanol and/or n-butanol), or isoprene.    TECHNOLOGY FOCUS - POLYMERS - Preferred Method: The lignin solvent has a density less than that of water, and the step of combining the lignin solvent and the lignin further involves separating water from the lignin solvent via gravity separation. The method additionally involves combining the lignin solvent and lignin with a biodiesel to provide a biodiesel fuel with improved energy density and gelling temperatures; extracting hemicellulose material from the fibrous plant material prior to extracting the lignin; pretreating at least a portion of the purified cellulose with a catalyst after forming the purified cellulose; and depolymerizing the pretreated cellulose by saccharification; and recycling the bio-product for the step of extracting the lignin. The step of extracting the lignin further involves extracting a purified cellulose component from the fibrous plant material; depolymerizing the cellulose by saccharification to form sugars after forming the purified cellulose; and fermenting the sugars to form a second bio-product. The step of fermenting the cellulose further involves selecting a particular microorganism for use in the fermentation to change the form of the second bio-product. Preferred Biofuel: The biofuel further comprises biodiesel to provide improved energy density and gelling temperatures. EXAMPLE - No suitable example is given.