An environmental “fairytail”: Removal of mercury from water via phage virion-based biosorption

Contamination of water with mercury constitutes a serious public health problem, especially in locations where the use of Hg occurs improperly/illegally and negligently, as is the case in the Amazon region (Brazil). The riverside populations in the Amazon are frequently invaded by illegal mining, exposing these populations to significant risks, of which contamination by heavy metals such as mercury (Hg²⁺) has the potential to cause serious illnesses. Furthermore, exposure to this metal causes neurological, cardiovascular, immune and digestive system disorders, in addition to damaging the lungs, kidneys, skin and eyes. The aquatic biome is extremely important for the local economy and population, being drastically affected by Hg²⁺ contamination and its effects. Therefore, it is necessary to develop bioremediation/biomitigation methods that are effective and less harmful to the environment, aiming to remove Hg²⁺ from water. Hence, when we think about new methodologies that can lead to the reduction of mercury in water, the use of protein entities is a potential option and, for this reason, we can highlight the possibility of using bacteriophage virions to remove Hg²⁺ ions from water by biosorption using their negative Zeta Potential for this purpose. In this sense, the main goal of the research work undertaken was to test the possibility of mitigating the presence of mercury (II) ions in water through the immobilization of a bacteriophage isolated and already characterized by our research group (EcoM021, T4 myovirus of the Straboviridae family and genus Tequatrovirus), on a chitosan-coated Ca-alginate microparticle support, through which water contaminated with Hg²⁺ ions was percolated. The system developed in microparticle form integrating trapped phage virions showed to be very promising for retaining mercury ions through biosorption (electrostatic attraction), thus enabling the removal of ionic mercury from water.