Abstract

Xinhui Wang, Yanling Jin*, Yang Fang, Yuhong Huang, Guohua Zhang, Xiaofeng Gao and Hai Zhao

To elucidate respective effects of sodium and chloride ion on filament formation in Zymomonas mobilis232B culture induced by NaCl, the morphological changes of cell grown in medium containing 0.2 M (NH4)2SO4, Na+ (as Na2SO4) and Cl- (as NH4Cl) were observed using a scanning electronic nicroscope (SEM). The occurrence of filament formation began as early as 4 h after exposuring to NaCl and Cland the length was approximate 10 to 15 μm after exposuring for 20 h, which was 3 to 5 fold longer compared to normal cell, while Na+ and (NH4)2SO4 treated cells kept normal morphology, indicating that filament formation in NaCl-inhibited Z. mobilis cultures is attributable to chloride ion. In the presence of 0.2 M chloride ion, increase in cell number stop almost immediately, whereas cells continued to elongate slowly, suggesting that chloride ion has a direct inhibitory effect on cell division.