| Title |
Isolation and Analyses of Uranium Tolerant Serratia marcescens Strains and Their Utilization for Aerobic Uranium U(VI) Bioadsorption |
| Author |
Rakshak Kumar1, Celin Acharya2, and Santa Ram Joshi1* |
| Address |
1Microbiology Laboratory, Department of Biotechnology & Bioinformatics, North-Eastern Hill University, Umshing, Shillong, Meghalaya 793022, India, 2Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, Maharashtra 400085, India |
| Bibliography |
Journal of Microbiology, 49(4),568-574, 2011,
|
| DOI |
|
| Key Words |
uranium-rich area, uranium-tolerant bacteria, Serratia marcescens, adsorption |
| Abstract |
Enrichment-based methods targeted at uranium-tolerant populations among the culturable, aerobic, chemoheterotrophic
bacteria from the subsurface soils of Domiasiat (India’s largest sandstone-type uranium deposits,
containing an average ore grade of 0.1% U3O8), indicated a wide occurrence of Serratia marcescens. Five
representative S. marcescens isolates were characterized by a polyphasic taxonomic approach. The phylogenetic
analyses of 16S rRNA gene sequences showed their relatedness to S. marcescens ATCC 13880 (≥99.4%
similarity). Biochemical characteristics and random amplified polymorphic DNA profiles revealed significant
differences among the representative isolates and the type strain as well. The minimum inhibitory concentration
for uranium U(VI) exhibited by these natural isolates was found to range from 3.5-4.0 mM. On
evaluation for their uranyl adsorption properties, it was found that all these isolates were able to remove
nearly 90-92% (21-22 mg/L) and 60-70% (285-335 mg/L) of U(VI) on being challenged with 100 μM (23.8
mg/L) and 2 mM (476 mg/L) uranyl nitrate solutions, respectively, at pH 3.5 within 10 min of exposure.
his capacity was retained by the isolates even after 24 h of incubation. Viability tests confirmed the tolerance
of these isolates to toxic concentrations of soluble uranium U(VI) at pH 3.5. This is among the first studies
to report uranium-tolerant aerobic chemoheterotrophs obtained from the pristine uranium ore-bearing site
of Domiasiat. |
