Ethanol is the most commonly used biofuel and can be produced on large scale via fermentation. The maximum theoretical yield for the production of ethanol was achieved around 20 years. A plasmid that carried the pyruvate decarboxylase and alcohol dehydrogenase genes from the bacteria Z. mobilis was used by scientists. This was inserted into E. coli and resulted in an increased yield of ethanol. The genome of this E. coli strain, KO11, has more recently been sequenced and mapped.