Production of gasoline from fermentable feedstocks

Compositions and methods for forming hexane, and, optionally, gasoline and/or components of a gasoline composition, from fermentable sugars are disclosed. The sugars are fermented using a bacteria or yeast that predominantly forms butyric acid. The butyric acid is subjected to Kolbe or photo-Kolbe electrolysis to form hexane. The hexane can be subjected to catalytic, reforming and/or isomerization steps to form higher octane products, which are or can be included in gasoline compositions. In one aspect, the fermentable sugars are derived from lignocellulosic materials such as wood products, switchgrass, or agricultural wastes. These materials are delignified to form lignin, cellulose and hemicellulose. The cellulose and hemicellulose are depolymerized to form glycose and xylose, either or both of which can be fermented by the bacteria. The lignin can be used to generate heat energy and/or electric energy for use in one or more process steps, such as the fermentation, product isolation, Kolbe electrolysis, catalytic reforming and/or isomerization steps. Alternatively, the lignin can be converted to synthesis gas, which can then be subjected to Fischer-Tropsch synthesis, or converted to methanol and/or ethanol. Thus, the methods described herein can convert biomass to a fuel composition or fuel additive, which can be used in a conventional gasoline engine, unlike traditional fuels such as ethanol or biodiesel.