The mass manufacture of biofuels could hold the key to greener, more environmentally sound energy, transportation and product options. Scientists have previously engineered metabolic pathways of microbes, making them tiny biofuel factories. Now, new research from an engineer at Washington University in St. Louis further refines the process, stitching together the best bits of several different bacteria to synthesize a new biofuel product that matches current engines better than previously produced biofuels.