Biobutanol, or butanol produced by biochemical means, is a 4-carbon alcohol which is considered an “advanced biofuel” or the ‘biofuel of the future” (replacing ethanol). Compared to ethanol, which is a 2-carbon alcohol, butanol offers many advantages: (1) a higher energy content, (2) less corrosion, (3) can be used as stand-alone fuel or in higher blends in gasoline without the need for engine modification and (4) can be easily transported in existing pipelines. However, there are many bottlenecks that need to be ironed out before large scale, low cost production of biobutanol can be realized. Like ethanol, butanol can also be produced from lignocellulosic biomass through a sequence of 4 steps: (1) pretreatment (removes the “lignin barrier” and “liberates” cellulose), (2) saccharification (enzymatic conversion of cellulose to simple sugars), (3) fermentation of sugars to ethanol, and (4) recovery of butanol from fermentation broth. And like ethanol, the bottlenecks are the cost of steps 1 to 3, and the problem of low yields due to toxicity of butanol to the fermenting organisms at high concentrations. Scientists at the United States Department of Agriculture (USDA) Agricultural Research Service (ARS) are developing modifications in the process for low cost, high yielding biobutanol production. The modifications involve combining steps 1 to 3 into a single step using bacteria and enzymes, utilizing a fed batch mode of feeding, and “gas stripping” (removal of the butanol from the fermentation product) to eliminate its toxic effects on the fermenting organism. Details of their work can be access at the USDA-ARS website (URL above)..