Enterobacter cloacae CYS-25 strain was isolated from a chromate plant. This bacterium was capable of resisting high hexavalent chromium concentration and reducing Cr（VI） under aerobic condition. CrO4^2- stimulated t...Enterobacter cloacae CYS-25 strain was isolated from a chromate plant. This bacterium was capable of resisting high hexavalent chromium concentration and reducing Cr（VI） under aerobic condition. CrO4^2- stimulated the increase of bacterial size and production of compact convex paths containing chromium on the bacterial surface. The increase of bacterial size was caused by integrative growth but not extracellular polymeric substance hyperplasia. IR and SDS-PAGE analyses showed the extracellular polymeric substance （EPS） components were mainly proteins and had no obvious changes whether the strains were induced by Cr（VI） or not. The EPS was amorphous and contained trivalent chromium. Under CrO4^2- growth condition, the extracellular substance of Enterobacter cloacae CYS-25 strains and Cr（VI） had redox reaction. The products were Cr^3＊-protein complexes which formed a piece of compact convex paths on the surface of bacteria and prevented Cr（VI） from entering into cells.展开更多
基金This work was supported by the National Natural Science Foundation of China (20501020, 40772034) Nanoscience Foundation of China (90406024)+2 种基金Natural Science Foundation of Fujian Province (No. X0650094/2006J0383)973 program (2007CB815601) the Special Project on Science and Technology of Fujian Province (2005YZ1026)
文摘Enterobacter cloacae CYS-25 strain was isolated from a chromate plant. This bacterium was capable of resisting high hexavalent chromium concentration and reducing Cr（VI） under aerobic condition. CrO4^2- stimulated the increase of bacterial size and production of compact convex paths containing chromium on the bacterial surface. The increase of bacterial size was caused by integrative growth but not extracellular polymeric substance hyperplasia. IR and SDS-PAGE analyses showed the extracellular polymeric substance （EPS） components were mainly proteins and had no obvious changes whether the strains were induced by Cr（VI） or not. The EPS was amorphous and contained trivalent chromium. Under CrO4^2- growth condition, the extracellular substance of Enterobacter cloacae CYS-25 strains and Cr（VI） had redox reaction. The products were Cr^3＊-protein complexes which formed a piece of compact convex paths on the surface of bacteria and prevented Cr（VI） from entering into cells.
