2.9. Morphological study of bacteria
The K.pneumoniae cells treated by different samples were collected after centrifugation (8000 rpm, 5 min) and rinsed three times with normal saline. Thereafter, the treated bacteria were fixed with 2.5% glutaraldehyde solution in dark for 4 h at 4 °C. Subsequently, the fixed samples were dehydrated for 10 min with sequential concentrations (30%, 50%, 70%, 80%, 90%, 95% and 100%) of ethanol solution, respectively, followed by observing under a scanning electron microscope.