Remediation of Mn (II), Cu (II), and Cr (VI) Using Dead Biomass of Thermophilic Bacteria Isolated from Himalayan Geothermal Springs: A Comparative Study

Aquatic ecosystems heavily impacted by heavy metal contamination are a serious issue for the environment. Therefore, the adoption of an affordable and effective bioremediation method will help to address this problem. The objective of this study was to examine the bioremediation potential of the thermophilic dead biomass of three isolates (GS1, BS1, and GWII) for the detoxification of manganese (Mn2+), copper (Cu2+), and chromium (Cr6+). These isolates were collected from water and soil sediment samples of Gauri Kund and Tapt Kund geothermal springs. The bacterial isolates were characterized as neutrophilic to alkali-tolerant and exhibited maximal growth at the optimum temperature of 55 °C under laboratory environment conditions. The results showed distinct affinities of the dead biomass for each thermophilic isolate for metal bioremediation. The sediment isolate GS1 (Gauri Kund) exhibits the highest metal removal affinities for Mn2+ (44.95%) and Cr6+ (53.89%), respectively, while BS1 (Tapt Kund) exhibits the highest metal-specific affinity for Cu2+ (53.51%). These findings highlight the significance of thermophilic dead biomass as a viable alternative for addressing microbial pathogenicity, metabolic dependence, and metal toxicity. Therefore, this method has proven to be a highly effective substitute for conventional treatment approaches.