The
Enterobacter cloacae CYS-25 strain isolated from a chromate plant shows a strong capability for chromateresistance instead of chromate reduction in aerobic conditions. In this study, atomic force microscopy (AFM) wasused for stud
ying the morphology characteristics of bacterial properties during the chromate resistance process. Theaverage length of
E. cloacae bacteria in the stationary phase is about 2.3 ± 0.6
m, while under the stimulation of400 mg/L CrO
42-, the length of bacteria increases to 3.2 ± 0.7
m. Height and phase images showed that, with theaddition of CrO
42-, the smooth surface of bacteria changed into one with discontinuous features with characteristicdimension of 40-200 nm. Analysis reveals that these compact convex patches are organic components stimulatedby CrO
42-. A chromate resistance mechanism relating to the overexpression of extracellular biologic components forpreventing the permeability of CrO
42- into the cell is proposed as the survival strategy of
E. cloacae in chromatesituation.