**Abstract**

Heavy metals accumulated the earth crust and causes extreme pollution. Accumulation of rich concentrations of heavy metals in environments can cause various human diseases which risks health and high ecological issues. Mercury, arsenic, lead, silver, cadmium, chromium, etc. are some heavy metals harmful to organisms at even very low concentration. Heavy metal pollution is increasing day by day due to industrialization, urbanization, mining, volcanic eruptions, weathering of rocks, etc. Different microbial strains have developed very efficient and unique mechanisms for tolerating heavy metals in polluted sites with ecofriendly techniques. Heavy metals are group of metals with density more than 5 g/ cm3 . Microorganisms are generally present in contaminated sites of heavy metals and they develop new strategies which are metabolism dependent or independent to tackle with the adverse effects of heavy metals. Bacteria, Algae, Fungi, Cyanobacteria uses in bioremediation technique and acts a biosorbent. Removal of heavy metal from contaminated sites using microbial strains is cheaper alternative. Mostly species involved in bioremediation include Enterobacter and *Pseudomonas* species and some of bacillus species too in bacteria. *Aspergillus* and *Penicillin* species used in heavy metal resistance in fungi. Various species of the brown algae and Cyanobacteria shows resistance in algae.

**Keywords:** heavy metal resistance, bioremediation, biosorption, bioleaching, plasmid
