Removal of heavy metals from contaminated water by thermophilic bacteria isolated from hot springs in Saudi Arabia

Abstract

The xenobiotic and heavy metals are major source of pollutants cause severe illness to the human body and harm ecosystem. Therefore, a study was designed to investigate role of microbes in removal to these contaminants. Two thermophilic bacterial strains (Brevibacillus borstelensis AK1.) and Anoxybacillus flavithermus AK1) were isolated from the Hot Springs of Saudi Arabia and categorised as S11 and S40 respectively. The strains were tested against eight heavy metals via Minimal inhibitory concentrations (MICs) to determine heavy metal resistance. Study revealed that B. borstelensis AK1 efficiently biodegrade Chromium and Nickle with MICs of 3 mm while A. flavithermus actively involved in removal of Chromium with MIC of 3.5 mm. In distilled water, the maximum removal (90%) of Aluminum was achieved by both bacterial strains. The S40 strain was effectively remove 21.6% manganese and 50.9% cadmium. The strain S11 was capable to remove 6.1% manganese. The highest rate of removal of Lead (97.4%) and aluminum (98.5%) was observed by S11 strains. The whole study was conducted on 24-hour incubation utilizing antibiotics cinoxacin, ciprofloxacin (70 µgmL-1) and ampicillin was (3 µgmL-1) for both strains (S11 and S40) as positive control. The current study provides baseline data regarding role of thermophiles in heavy metals removal from water and in future more studies are required to identify the genetic aspects and related pathways associated with the heavy metals removal.