Role of microorganisms in bio-removal of heavy metals

Increasing metal contamination in the environment, foods, and drinking water due to industrial activities is one of the most concerns all over the world. Among all chemical, physical, and biological techniques used for reducing these contamination, bio-removal approach has attracted interest as a green ecofriendly, inexpensive, and simple method for decontamination of metals from soil, foodstuffs, and water. As a matter of interest, biological decontamination of heavy metals in food is discussed in the current review paper.

After an introduction about importance and concerns about heavy metal pollutions, main reported microorganisms for bio-removal of Lead, Cadmium, Mercury, and Arsenic are addressed. Then, the main influencing variables on biosorption efficiency including pH, bacterial concentration, temperature, and contact time have been reviewed. Finally, maximum permitted levels of the pollutants in foods and feeds, and their effect on human health are reported. Choosing a suitable microorganism under appropriate condition is important in heavy metals bio-removal. In addition, matrix of the media (food, drinking or waste water, and soil) is another important issue. Other than providing optimum external variables for the microorganisms, having lipids, carbohydrate, and other necessary nutrients in the matrix would increase the biosorption effectiveness.