ORIGINAL PAPER Ecotoxic heavy metals transformation by bacteria and fungi in aquatic ecosystem Amiy Dutt Chaturvedi 1 • Dharm Pal 2 • Santhosh Penta 3 • Awanish Kumar 4 Received: 24 April 2015 / Accepted: 24 July 2015 Ó Springer Science+Business Media Dordrecht 2015 Abstract Water is the most important and vital molecule of our planet and covers 75 % of earth surface. But it is getting polluted due to high industrial growth. The heavy metals produced by industrial activities are recurrently added to it and considered as dangerous pollutants. Increasing concentration of toxic heavy metals (Pb 2? , Cd 2? , Hg 2? , Ni 2? ) in water is a severe threat for human. Heavy metal contaminated water is highly carcinogenic and poisonous at even relatively low concentrations. When they discharged in water bodies, they dissolve in the water and are distributed in the food chain. Bacteria and fungi are efficient microbes that frequently transform heavy metals and remove toxicity. The application of bacteria and fungi may offer cost benefit in water treatment plants for heavy metal transformation and directly related to public health and environmental safety issues. The heavy metals trans- formation rate in water is also dependent on the enzymatic capability of microorganisms. By transforming toxic heavy metals microbes sustain aquatic and terrestrial life. Therefore the application of microbiological biomass for heavy metal transformation and removal from aquatic ecosystem is highly significant and striking. This paper reviews the microbial transformation of heavy metal, microbe metal interaction and different approaches for microbial heavy metal remediation from water bodies. Keywords Heavy metals  Ecotoxic  Microbes  Transformation  Remediation Introduction Bacteria and fungus are unique microorganisms that play a major role in the biotransformation of heavy metals. Water bodies contribute significantly for both aquatic as well as terrestrial life but they become polluted progressively due to mass development of industries and this is harmful for the surrounding life (Congeevaram et al. 2007). Municipal water and industrial waste discharge in water bodies damage the quality of water and affects the aquatic life. Due to globalization, increase in population and industrial development causes deposition of heavy metals in lakes and rivers. These are major issues that have been discussed by the developing and developed countries at world sce- nario (Souza and Tundisi 2003). Scientific approach may lead to solve these problems at in vitro to in vivo level as suggested by Hoppe (1993). A large number of populations were affected by mercury pollution in Minamata, Japan. It was caused by the release of mercury from chemical industry in Minamata Bay. This highly toxic mercury accumulated in the fish which was later eaten by the local population and resulted into mercury poisoning (Chang and Guo 2009). Loss of appetite, nausea, irritability, and muscular stiffness are common due to minor exposure of heavy metal to human. Prolonged exposure to different heavy metals such as cadmium, copper, lead, nickel and zinc can cause injurious effects on aquatic life as well as humans (Yan and Viraraghavan 2000). Despite the adverse & Awanish Kumar drawanishkr@gmail.com; awanik.bt@nitrr.ac.in 1 Department of Biochemistry, Shri Shankaracharya Mahavidyalaya, Bhilai, India 2 Department of Chemical Engineering, National Institute of Technology Raipur, Raipur, India 3 Department of Chemistry, National Institute of Technology Raipur, Raipur, India 4 Department of Biotechnology, National Institute of Technology Raipur, Raipur, Chhattisgarh 492010, India 123 World J Microbiol Biotechnol DOI 10.1007/s11274-015-1911-5