| Virginia
Journal of Science.
2002. Vol 53 (3) : 141-155 |
| Chromium
Tolerant Microbial Communities from the Chesapeake Bay Watershed Kristine L. Lowe1, Ruth E. Fliflet1, Tony Ly1, Brenda J. Little2 and Joanne Jones-Meehan1, 1Chemistry Division, Code 6115, Naval Research Laboratory, Washington, DC 20375 2Oceanography Division, Code 7303, Naval Research Laboratory, Stennis Space Center, MS 39529. ABSTRACT
Chromium tolerant bacteria were enumerated from portions of the
Chesapeake Bay watershed and examined for their potential to reduce
Cr(VI). Water and sediment samples were collected from various
locations in Baltimore Harbor and Bear Creek, as well as Sandy Point
State Park in Maryland and the Anacostia River in Washington, DC.
Samples were spread onto agar plates with CrO42-
(5 ppm) as the sole terminal electron acceptor. Plates were incubated
anaerobically and colony forming units (CFU) enumerated. CFU arising on
minimal-CrO42- medium ranged from 103-104
mL-1 or g-1 and community estimates from sites in
proximity to Baltimore City were approximately 6-30X higher than distal
sites. Bacterial identification by BIOLOG™ or 16S rRNA sequencing
indicated the presence of bacteria of the genera Klebsiella, Pseudomonas, Burkholderia,
Kluyvera and others. Typical Cr(VI) reduction rates by these
isolates were significantly lower than Shewanella oneidensis, a known
metal-reducing bacterium. Results suggested that microbial communities
in the Chesapeake Bay watershed, particularly in Baltimore Harbor and
Bear Creek, had a high tolerance for Cr(VI) and/or could grow slowly
with Cr(VI) as a terminal electron acceptor. However, the isolates did
not rapidly degrade Cr(VI) in the laboratory.Key Words: Chromium tolerance, Shewanella, contaminant metals, Chesapeake Bay |