In situ polychlorophenol bioremediation potential of the indigenous bacterial community of boreal groundwater.
The composition and chlorophenol-degrading potential of groundwater bacterial community in a permanently cold, oxygen-deficient chlorophenol contaminated aquifer at Kärkölä, Finland was studied with the aim of evaluating in situ bioremediation potential. The groundwater contained from 10(4) to 10(7) microscopically counted cells/ml and up to 10(5) CFU/ml heterotrophic bacteria cultivable at 8 and 20 degrees C. Of the 102 pure cultures, of which 86% Gram-negative, from the plume area (10,000 microg of chlorophenols/l), 57% degraded 2, 3, 4, 6-tetrachlorophenol (TeCP), the main component of the wood preservative which was the source of contamination: 17% also degraded pentachlorophenol (PCP). The degraders were scattered among 16 different clusters of Gram-negatives mainly proteobacteria and members of Cytophaga/Flexibacter/Bacteroides phylum judged by the composition of whole-cell fatty acids. Only one Gram-positive degrading cluster was found containing seven actinobacteria closest to Nocardioides. Of the 88 pure cultures isolated from outside the plume (< 10 microg of chlorophenols/l) 67% were Gram-negative. Seven percent of the isolates degraded 2, 3. 4, 6-TeCP and/or PCP. Five of the Gram-positive isolates from outside the plume were Mycobacterium/Rhodococcus-related actinobacteria and O-methylated 2, 3, 4, 6-TeCP and PCP. The results show that chlorophenol degrading bacterial flora had been enriched as a result of contamination of the aquifer. This suggests significant in situ bioremediation potential of the site.
Männisto
M K
MK
Institute of Environmental Engineering and Biotechnology, Tampere University of Technology, Finland. minna.mannisto@tut.fi
Salkinoja-Salonen
M S
MS
Puhakka
J A
JA
D001419:Bacteria / Q000378:metabolism*; D001439:Bacteroides / Q000254:growth & development / Q000378:metabolism; D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology; D002733:Chlorophenols / Q000378:metabolism*; D003080:Cold Temperature; D015169:Colony Count, Microbial; D003589:Cytophaga / Q000254:growth & development / Q000378:metabolism; D005227:Fatty Acids / Q000032:analysis; D005387:Finland; D005618:Fresh Water / Q000032:analysis / Q000737:chemistry / Q000382:microbiology*; D006090:Gram-Negative Bacteria / Q000254:growth & development; D006094:Gram-Positive Bacteria / Q000254:growth & development; D010100:Oxygen / Q000737:chemistry; D010416:Pentachlorophenol / Q000378:metabolism*
D002733:Chlorophenols; D005227:Fatty Acids; C031487:2,3,4,6-tetrachlorophenol; D010416:Pentachlorophenol; D010100:Oxygen