Adenosine Triphosphate and Carbon Efficient Route to Second Generation Biofuel Isopentanol

Climate
change necessitates the development of CO2 neutral
or negative routes to chemicals currently produced from fossil carbon.
In this paper we demonstrate a pathway from the renewable resource
glucose to next generation biofuel isopentanol by pairing the isovaleryl-CoA
biosynthesis pathway from Myxococcus xanthus and
a butyryl-CoA reductase from Clostridium acetobutylicum. The best plasmid and Escherichia coli strain combination
makes 80.50 ± 8.08 (SD) mg/L of isopentanol after 36 h under
microaerobic conditions with an oleyl alcohol overlay. In addition,
the system also shows a strong preference for isopentanol production
over prenol in microaerobic conditions. Finally, the pathway requires
zero adenosine triphosphate and can be paired theoretically with nonoxidative
glycolysis, the combination being redox balanced from glucose thus
avoiding unnecessary carbon loss as CO2. These pathway
properties make the isovaleryl-CoA pathway an attractive isopentanol
production route for further optimization.