Ethanol provides the first model for biofuel commercialization. However, in order to make the cellulosic ethanol process economically viable, both government subsidies and scientific

R&D are still required. And it is generally accepted that ethanol alone is not going to provide a long-term solution to meet society’s energy needs (Hill et al., 2006). It suffers from a somewhat low energy density, inability to be transported through pipelines and fairly high cost for extraction from fermentation broths. This is opening the door to developing many other molecules as replacements for ethanol and thus, discovering new fuel molecules to be produced via microbial biotechnology.