Characterization of a thermo-adapted strain of Zymomonas mobilis for ethanol production at high temperature.

A thermo-adapted strain of Zymomonas mobilis designated ZM AD41 that capable of growth and ethanol production at high temperature was obtained using the thermal stress adaptation technique. This thermo-adapted strain exhibited approximately 1.8- and 27-fold higher growth rate than the wild-type at 39 °C and 41 °C, respectively. It was more resistant to stress induced by acetic acid at 200 mM and hydrogen peroxide (H2O2) at 0.4 mM and produced approximately 1.8- and 38.6-fold higher ethanol concentrations than the wild-type at 39 °C and 41 °C, respectively. Moreover, it had better sedimentation performance during ethanol fermentation at high temperature than the wild-type. Based on the growth performance, heat, acetic acid and H2O2 stress treatments, sedimentation characteristics, and ethanol fermentation capability, Z. mobilis ZM AD41 was a good candidate for ethanol production at high temperature.