Biofilm-Mediated Heavy Metals Bioremediation

Industrial activities have generated wastes globally and are still being created and dumped, resulting in contaminated environments (terrestrial as well as aquatic). Industrial wastes include polycyclic aromatic hydrocarbons, polythene, dyes, phenols, and heavy metals which degrade the quality of soil and cause havoc to ecosystem, animal, and human welfare. In order to overcome from the problem, various remediation strategies have been initiated such as land sparing, soil excavation, crop rotation, land sharing, and offsite treatment. While these methods require trained workers and could potentially introduce harmful substances into the environment. These are capable of removing and detoxifying the heavy metal contamination. Microbial communities produce extracellular polymeric substance (biofilm) that enhances the colonization of microbial cells and shields them in harsh environmental conditions. Biofilm formation is a natural character, exhibited by microbes growing on natural and artificial surfaces. In biofilms, multiple microorganisms reside together and degrade the pollutants in polluted soil and groundwater. Biofilm functions through cell signalling and quorum sensing to remove metal contamination from the environment. These microbes include Gram-positive, Gram-negative bacteria, cyanobacteria, fungi, and microalgae. Microbial biofilms are used as biomarkers and biofilters when pollution is on large scale. Bioremediation is a developing technology and has attracted interests in research and development. This chapter provides clear idea about toxicity of heavy metals in environment and the role of microbial biofilms in bioremediation of heavy metals from environment.