The production of liquid fuels from biological material ('biomass') is gaining increasing interest worldwide. Climate change, rising fuel prices, political instability and depletion of petroleum resources are some of the recent concerns that have sparked this interest into alternatives from fossil fuels. As a result, many different biomass sources are being evaluated as suitable feedstocks for biofuel production, and these range from plant material, to animal waste, to microorganisms such algae and genetically engineered bacteria. Currently, Brazil and the United States, which make bio-ethanol from sugarcane and maize, respectively are the two major players for commercial biofuel production. In addition, there is a growing global production of bio-diesel from the oil extracted from oil-rich crops such as canola and soybean. More recently, research has focused on whether microbial systems can be exploited for the biosynthesis of a wide range of liquid biofuels.