It seems that Z. mobilis is capable of tolerating high concentrations of sucrose than of glucose on molar basis. The ethanol yields by Z. mobilis on molasses are low as compared to pure substrates like glucose, fructose or sucrose. Efforts have been made to improve its fermentation efficiency. These observations are based on the study of effect of temperature on fermentation of sucrose by Zymomonas mobilis. The optimum pH range and temperature for fermentation is between 5 to 7 and 30oC, respectively. This necessitates sterilization of fermentation medium.