Improving cellulosic ethanol fermentability of Zymomonas mobilis by overexpression of sodium ion tolerance gene ZMO0119.

Inhibition of sodium ion (Na+) on Zymomonas mobilis represents an important obstacle for efficient cellulosic ethanol production. This study screened and overexpressed the genes responsible for transporting metal ions in Z. mobilis for increasing its Na+ tolerance. The ZMO0119 gene encoding Na+/H+ antiporter was identified to be highly effective for reducing intracellular Na+ concentration of Z. mobilis by improving the Na+ transport capacity. Overexpression of ZMO0119 gene in Z. mobilis significantly accelerated the cell growth, glucose consumption, and cellulosic ethanol production from the dry acid pretreated and biodetoxified corn stover feedstock. This study provided an important gene responsible for increasing the cellulosic ethanol fermentability by Z. mobilis.