Butanol may be used as a fuel in an internal combustion engine. Because its longer hydrocarbon chain causes it to be fairly non-polar, it is more similar to gasoline than it is to ethanol. Butanol has been demonstrated to work in vehicles designed for use with gasoline without modification. University of California, Berkeley, chemists have engineered bacteria to churn out a gasoline-like biofuel (butanol) at about 10 times the rate of competing microbes, a breakthrough that could soon provide an affordable transportation fuel. The potential feedstocks are the same as for ethanol: energy crops such as sugar beets, sugar cane, corn grain, wheat and cassava, prospective non-food energy crops such as switchgrass and even guayule in North America, as well as agricultural byproducts such as straw and corn stalks.