Bioremediation of Mn2+ by Thermophilic Bacterial Isolates of Tapt Kund, Soldhar, and Gauri Kund, Hot Springs of Uttarakhand, India

Abstract

Heavy metals are considered to be the most prevalent contaminants in industrial effluent.  Effective remediation is necessary to address the global issue of groundwater pollution caused by some toxic heavy metals such as iron (Fe). This study provides an effective approach for possibly employing a thermophilic bacterial strain to remove excess iron from effluent water and the environment. The Gauri Kund hot spring in Uttarakhand (India) evolved the Fe-resistant bacterial isolate (GA6), which was determined to have the highest metal resistance activity for Fe.  The 16S rRNA sequencing with a percentage identity of 98.14% of this isolate was identified as Bacillus thermophilus HS-BTL2. According to the results, the Bacillus thermophilus HS-BTL2 bacteria was effectively able to extract iron from its solutions when cultured at the specific conditions of temperature (55 ^oC), and pH 7.0, for 48 hours.  The dead biomass of Bacillus thermophilus HS-BTL2 was able to extract a significantly higher 91.79% iron from the metal-contaminated solution. Whereas a live bacterial cell of Bacillus thermophilus HS-BTL2 can only biosorb 86.17% iron, which is comparatively lower than the dead biomass of bacterial strain. After direct inoculation of the Bacillus thermophilus HS-BTL2 into the industrial effluent water, this strain was successfully capable of bioremediating 63.94% of the iron metal ions from the effluent. The results of this study concluded that the rate of dead biomass of Bacillus thermophilus was comparatively higher in dead biomass rather than the live biomass of thermophilic bacteria.