ABSTRACT
The pollution caused by heavy metals has become a serious problem due to its detrimental impacts on environmental and human health. The current situation demands an eco-friendly, economical, and effective approach for the remediation of varying concentrations of heavy metals from wastewater. Microorganisms such as bacteria, fungi, and algae have gained appreciable attention due to their ability in remediating different heavy metals from wastewater. However, for the sake of simplicity, investigations are concerned with remediation of high concentrations of single metal rather than the low levels of complex mix of different heavy metals, a situation that is encountered in actual contaminated environments. This chapter covers those selected studies that describe simultaneous removal of multiple heavy metals by different microorganisms. This chapter discusses the uptake capacity of different microbes and the effect of interfering metal ions and various factors influencing the uptake rate of heavy metals. It is apparent from the studies that although microbes are efficient biosorbents to uptake heavy metals even at low concentrations, their capacity declines when subjected to binary or ternary mixtures. Very few attempts have been made to understand the response of metabolically active microbes/consortium under multiple metal stress and to harness diverse mechanisms of metal uptake under complex scenarios. More research is needed toward understanding the process mechanisms, selecting the best microbial strain/consortia for multimetal removal, and developing suitable bioreactors to improve the simultaneous uptake of multiple heavy metals from wastewater.
