Biochemical, Molecular Characteristics, and Bioremediation Properties of Mn²⁺- Resistant Thermophilic Bacillus Strains

Manganese (Mn) groundwater poisoning, through industrial discharge, is a global challenge that requires effective remediation. In this study, the biochemical, and molecular characteristics of metal-resistant thermophilic bacterial strains are examined with their bioremediation properties. Three Mn-resistant bacterial isolates namely TA8, SA9, and GA7 were isolated from the 3 different hot springs, and identified with the highest metal resistance activity for Mn²⁺. The 16 S rRNA sequencing identification with similarities 96.53%, 99.10%, and 99.86% of those isolates was identified respectively, as Bacillus aerius strain CCMMB964, Oceanobacillus caeni strain JNW-23, and novel, Bacillus composti strain SgZ-9. The metal tolerance capabilities of the strains were evaluated through minimum inhibitory concentration (MIC) and the metal biosorption rate was determined by the live cell bioremediation method. Bacillus aerius strain CCMMB964 has the highest MIC (600 µg/lt.) with a 98.34% Mn bioremediation rate. Oceanobacillus caeni strain JNW-23 has MIC value 525 µg/lt with 77.74% Mn biosorption. The MIC of Bacillus composti strain SgZ-9 was 475 µg/lt. with 61.17% Mn removal efficiency. Bacillus aerius strain CCMMB964 (TA8) has demonstrated the greatest potential (98.34%) among all the strains and is confirmed as the most potent strain of thermophilic bacteria for the Mn bioremediation. This research could offer a novel, economical, and environmentally beneficial approach to reducing metal toxicity.