Abstract
Biofuels come in a variety of forms: from wood, the classic biofuel, to liquid fuels like ethanol, higher alcohols, and the energy-dense biodiesel. Given the recent uncertainty of fuel prices and the certainty of global climate change, there has been much focus on fuels from renewable sources. Researchers and corporations are looking toward a fermentative route to produce fuels as well as chemicals that had been traditionally produced using petroleum feedstocks. The key challenge for effective biofuel production and distribution is controlling the cost of production. We as researchers can begin to address this by utilizing waste carbon as the feedstock for fermentative fuel production. Many different feedstocks, including lignocellulose and carbon dioxide, are being considered for production of alcohol fuels or lipids that would be used for production of biodiesel. This chapter is a survey of the most common liquid biofuels that are being produced by fermentative means using robust biocatalysts and renewable feedstocks.