Heavy metal removal by Bacillus for sustainable agriculture

Microbial biosorbents are widely used for the removal of various toxic metals which pose a significant threat to agriculture. Metals like cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, palladium, platinum, and zinc are the predominant metal contaminants in our soils and water which call for instantaneous action to design microbiological techniques for effective bioremediation. The associated anthropogenic activities lead to a significant release of toxic metals into the environment purposely. Various industries related to mining, surface finishing, energy and fuel producing, fertilizer, pesticide, metallurgy, iron and steel, electroplating, electrolysis, paints and ceramic discharge metal laden effluents result in severe environmental pollution and health hazards. An indefinite persistence of heavy metals in the environment is a potential health hazard as it leads to bioaccumulation of toxic metals in the crops that eventually leads to biomagnification upon entering the food chain. This chapter highlights the promises of Bacillus as a potential biosorbent for the effective removal of toxic heavy metals from the environment. Numerous members of the genus Bacillus, like B. subtilis, B. thuringiensis, B. sterothermophilus, B. megaterium, B. cereus, B. pumilus, B. licheniformis, and B. jeotgali have been reported to remove heavy metals most effectively. Diverse functional groups like carboxyl, amino, amide, phosphate, and hydroxyl groups