Bioaugmentation of activated sludge by an indigenous 3-chloroaniline-degrading Comamonas testosteroni strain, I2gfp.
A strain identified as Comamonas testosteroni I2 was isolated from activated sludge and found to be able to mineralize 3-chloroaniline (3-CA). During the mineralization, a yellow intermediate accumulated temporarily, due to the distal meta-cleavage of chlorocatechol. This strain was tested for its ability to clean wastewater containing 3-CA upon inoculation into activated sludge. To monitor its survival, the strain was chromosomally marked with the gfp gene and designated I2gfp. After inoculation into a lab-scale semicontinuous activated-sludge (SCAS) system, the inoculated strain maintained itself in the sludge for at least 45 days and was present in the sludge flocs. After an initial adaptation period of 6 days, complete degradation of 3-CA was obtained during 2 weeks, while no degradation at all occurred in the noninoculated control reactor. Upon further operation of the SCAS system, only 50% 3-CA removal was observed. Denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes revealed a dynamic change in the microbial community structure of the activated sludge. The DGGE patterns of the noninoculated and the inoculated reactors evolved after 7 days to different clusters, which suggests an effect of strain inoculation on the microbial community structure. The results indicate that bioaugmentation, even with a strain originating from that ecosystem and able to effectively grow on a selective substrate, is not permanent and will probably require regular resupplementation.
Boon
N
N
Laboratory of Microbial Ecology and Technology, Ghent University, B-9000 Ghent, Belgium.
Goris
J
J
De Vos
P
P
Verstraete
W
W
Top
E M
EM
D000814:Aniline Compounds / Q000378:metabolism*; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification; D001673:Biodegradation, Environmental; D019149:Bioreactors; D020604:Comamonas testosteroni / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media; D017753:Ecosystem; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D020459:Genes, rRNA; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*; D018508:Water Purification
D000814:Aniline Compounds; D003470:Culture Media; D008164:Luminescent Proteins; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D049452:Green Fluorescent Proteins; C031392:3-chloroaniline; C023650:aniline