In this study,we used both metabolism-based plasmid addiction systems for the production of 1-butanol. The essential anabolic system that we targeted was lipopolysaccharide(LPS) biogenesis,specifically the essential lptB
gene. LPS is a cell surface glycolipid that is required for viability of E. coli. LptB is also essential for survival because it functions as the ATPase of the ABC transporter that powers LPS transport to the cell surface (Sherman etal.,2014;Sperandeoetal.,2008).