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 .