Chitosan regularly contains three types from reactive functional groups, at C-2, C-3, and C-6 positions, i.e. amino group, primary hydroxyl groups and secondary hydroxyl groups, respectively [15]. The varied physico-chemical characteristics of chitosan contribute to its bioactive properties, e.g. molecular weights (50–2000 kDa), deacetylation degrees (70–95%), pKa values and viscosity [16]; these physiognomies could directly influence its targeted applica- tion [17].
From the successful applications of chitosan biopolymers, espe- cially from fungal sources, are their use as powerful antimicrobial agent, coagulation factor, chelating agent for heavy metals adsorp- tion [9,18–22].
However, the current study was designed to produce fungal chi- tosan from C. elegans and to use it for the elimination of water pollutants, e.g. heavy metals and waterborne microorganisms, and to investigate its antibacterial mode of action against E. coli.