Cyanobacteria as a potent platform for heavy metals biosorption: Uptake, responses and removal mechanisms

Towering up of heavy metal (HMs) contamination in varied natural ecosystems sensitize the scientific community to think up of its remediation preferably with biosorbing components. With ease of growth along with little requirement for sustenance, cyanobacterial members (living and non- living biomass) have been considered as one of the suitable alternative for the purpose in recent years. Presence of proton active functional groups in the cell wall and polymeric substances in the exo-polysaccharidic (EPS) layer make them competent enough to adsorb and absorb the positively charged metal ions. The metal ions, once incorporated are transported into the cytoplasm and dispersed therein whereas, HMs are being adsorbed directly from the substratum when treated with nonliving biomass. Such mechanisms could be now visualized with help of kinetic models. Genetically modified cyanobacterial cells too take part in overproduction of metallothionein protein, EPS and trehalose for enhancing the mechanism of biosorption processes in which kinetic models are yet to be developed.