Relationship of Biodiversity with Heavy Metal Tolerance and Sorption Capacity: A Meta-Analysis Approach

Microbial remediation of metals can alleviate the concerns of metal pollution in the environment. The microbial remediation, however, can be a complex process since microbial metal resistance and biodiversity can play a direct role in the bioremediation process. This study aims to understand the relationships among microbial metal resistance, biodiversity, and metal sorption capacity. Meta-analyses based on 735 literature data points of minimum inhibitory concentrations (MIC) of Plantae, Bacteria, and Fungi exposed to As, Cd, Cr Cu, Ni, Pb, and Zn showed that metal resistance depends on the microbial Kingdom and the type of heavy metal and that consortia are significantly more resistant to heavy metals than pure cultures. A similar meta-analysis comparing 517 MIC values from different bacterial genera (Bacillus, Cupriavidus, Klebsiella, Ochrobactrum, Paenibacillus, Pseudomonas, and Ralstonia) confirmed that metal tolerance depends on the type of genus. Another meta-analysis with 195 studies showed that the maximum sorption capacity is influenced by microbial Kingdoms, the type of biosorbent (whether consortia or pure cultures), and the type of metal. This study also suggests that bioremediation using microbial consortia is a valid option to reduce environmental metal contaminations.