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Bacterial community composition determined by culture‐independent and ‐dependent methods during propane‐stimulated bioremediation in trichloroethene‐contaminated groundwater
Author(s) -
Con Stephanie A.,
Tovanabootr Adisorn,
Dolan Mark,
Vergin Kevin,
Giovani Stephen J.,
Semprini Lewis
Publication year - 2005
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2004.00680.x
Subject(s) - bioremediation , biology , groundwater , microbial population biology , library , environmental chemistry , propane , microorganism , microbiology and biotechnology , population , bacteria , contamination , 16s ribosomal rna , ecology , chemistry , genetics , demography , geotechnical engineering , organic chemistry , sociology , engineering
Summary An in situ co‐metabolic air sparging (CAS) study was carried out at McClellan Air Force Base (MAFB), Sacramento, CA, USA, in a trichloroethene‐ (TCE) and cis ‐dichloroethene ( cis ‐DCE)‐contaminated aquifer where one test zone received 2% propane in air and the other served as a control and received only air. As part of that study, bacterial population shifts were evaluated by length heterogeneity polymerase chain reaction (LH‐PCR). The results showed that an organism(s) that had a fragment size of 385 bp was positively correlated with propane removal rates. The 385 bp fragment consisted of up to 83% of the total fragments in the analysis when propane removal rates peaked. A 16S rRNA clone library made from the bacteria sampled from the propane‐sparged groundwater included clones of a TM7 division bacterium that had a 385 bp LH‐PCR fragment; no other bacterial species with this fragment size were detected. Both propane removal rates and the 385 bp LH‐PCR fragment decreased as nitrate levels in the groundwater decreased. Extinction culturing in natural unamended groundwater medium was used to assess the bacterial diversity of the culturable fraction of microorganisms in both CAS and air‐sparged groundwater and to bring novel species into culture for further study. The dominant cultures acquired from the CAS groundwater were from the Herbaspirillum/Oxalobacter clade. The dominant cultures from the air‐sparged groundwater were from a novel beta‐Proteobacterial clade, which we named after isolate HTCC333.