greatly increased with the increasing of metal concentration, especially for Cu and Zn. The highest chitosan qe (113.44) was recorded with Cu ions at their highest concentration (288.63 ppm). Although just traces from Zn (0.06 ppm) were resided from the ini- tial concentration of 98.25 ppm, after treatment with chitosan, the highest chitosan qe (109.20) was recorded at the concentration of 283.35 ppm from Zn2+ ions. On the other hand, the lowest adsorp- tion capacity of fungal chitosan, in the highest concentration level of metals, was recorded with Pb2+ at concentration of 286.46 ppm.
The impact of bacterial exposure to fungal chitosan is illustrated in Fig. 3. While the control E. coli cells appeared with a normal shape and smooth surface (Fig. 3A), cells began to lyse and combine with each other’s after 3 h of exposure (Fig. 3B), and many chitosan particles appeared attached within the combined cells (arrows). After 6 h of exposure (Fig. 3C), most of bacterial cells were swelled and severe alterations in their cell wall appeared, chitosan particles became more integrated and mixed with lysed cell matrix. At the end of exposure, after 12 h (Fig. 3D), the entire bacterial cell walls were fully disrupted; a matrix, from interior cellular debris and lyses cell walls residues, were appeared. Chitosan particles could not easily be detected in this stage.