A review of isolation and characterization of heavy metal and antibiotic co-resistant bacteria from tannery effluent

Abstract

The use of heavy metals in the tannery industry for leather processing and discharge of untreated effluents from this industry in the environment is a leading challenge to solve. Hence, micro-organism has a great potential to grow in the presence of toxic substances and it is a novel, cost-effective and eco-friendly approach to remove these heavy metals (Cr, Pb, Cu, Zn) from these contaminated sites and safeguard our environment. Toxic substances are hard to degrade, and microbes develop detoxifying mechanisms to counteract these substances' toxic effects. This article reviews the isolation of the heavy metal resistant bacteria and their ability to co-resistant against the antibiotic. Escherichia coli, Staphylococcus sp., Klebsiella sp., Pseudomonas sp. was identified to resist toxic substances to a minimum inhibitory concentration. In some cases, the same isolates showed co-resistance to multiple heavy metals. All the isolates were also resistant to several antibiotics. My study highlights the organisms' physiological color change in response to any stimuli like heavy metals as the media is incorporated with the heavy metals. Besides, interaction with different toxic compounds is still unclear if these patterns of color change are simply the consequences of heavy metals or any underlying factor or enzyme is responsible for the color transformation.