Influence of backwashing on the microbial community in a biofilm developed on biological activated carbon used in a drinking water treatment plant.
The influence of backwashing on the biofilm community developed on biological activated carbon (BAC) used in a drinking water treatment plant was investigated by means of bacterial cell enumeration and terminal-restriction fragment length polymorphism (T-RFLP) fingerprinting analysis of bacterial and eukaryotic ribosomal RNA genes (rDNA). After backwashing, the attached bacterial abundance in the top layer of the BAC bed decreased to 64% of that before backwashing. The community level changes caused by backwashing were examined through the T-RFLP profiles. In the bacterial 16S rDNA analysis, the relative abundances of some terminal-restriction fragments (T-RFs) including the Planctomycetes-derived fragment increased; however, the relative abundances of some T-RFs including the Betaproteobacteria-derived fragments decreased. In the eukaryotic 18S rDNA analysis, the relative abundances of some T-RFs including the protozoan Cercozoa-derived fragments increased; however, the relative abundances of some T-RFs including the metazoan Chaetonotus- and Paratripyla-derived fragments decreased. The T-RFLP analysis suggests that backwashing can cause changes in the relative compositions of microorganisms in a BAC biofilm in the top layer of the bed.
Kasuga
I
I
Department of Water Supply Engineering, National Institute of Public Health, 2-3-6 Minami, Wako City, Saitama 351-0197, Japan. kasuga@env.t.u-tokyo.ac.jp
Shimazaki
D
D
Kunikane
S
S
D000818:Animals; D001483:Base Sequence; D020562:Betaproteobacteria / Q000502:physiology; D018441:Biofilms / Q000145:classification* / Q000254:growth & development; D002244:Carbon; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis; D056890:Eukaryota / Q000502:physiology; D012150:Polymorphism, Restriction Fragment Length; D018508:Water Purification / Q000379:methods*
D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D002244:Carbon