Isolation, characterization and bioremediation efficiency of some bacterial strains from Aurangabad, India with reference to heavy-metal polluted water in a lab-scale microcosm

Abstract

Inherent heavy metal presence in soil is exacerbated by geological and anthropogenic activities, posing threats to both plant and animal life. This study isolates 11 bacteria from Naregaon garbage and Yash Raj Engineering soil samples, with 6 strains demonstrating adept hydrolysis of various metal ions (Cu, Co, Mn & Cr) for growth. The most efficient bacterial isolate in degrading heavy metals was identified as Achromobacter sp. HM6 through 16S rRNA sequencing and remaining isolates were identified as Kocuria pelophila, Paenarthrobacter nitroguajacolius, Liquorilactobacillus mali, Burkholderia cepacia, Bacillus megaterium as per Bergey's Manual and ABIS software. In laboratory-scale experiments, these isolates demonstrated substantial remediation of heavy metal-polluted water (78% Lead, 82% Cobalt, 90% Chromium, and 92% Copper) within 15-20 days. Optimal conditions determined through Plackett-Burman design (pH 6.9, Temp 40.5℃, and sub 0.06%) yielded a 96% bioremediation efficiency within 4.5 days. Furthermore, landfilling bioremediation reduced the toxicity of heavy metals (Fe, Zn, Mn & Cu) in polluted soil by 80-90%, and land farming bioremediation significantly enhanced overall plant growth compared to control conditions. These findings highlight the capability of the isolated bacteria to eco-friendly and cost-effectively mitigate the toxicity of heavy metals in polluted soils and water, offering a sustainable solution for environmental remediation.