Open AccessQuantification of Hyphomicrobium Populations in Activated Sludge from an Industrial Wastewater Treatment System as Determined by 16S rRNA Analysis
Author(s) -
Alice C. Layton,
P. N. Karanth,
Curtis A. Lajoie,
A. J. Meyers,
I. R. Gregory,
Raymond D. Stapleton,
D. E. Taylor,
Gary S. Sayler
Publication year - 2000
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.66.3.1167-1174.2000
Subject(s) - biology , 16s ribosomal rna , activated sludge , microbiology and biotechnology , strain (injury) , ribosomal rna , phylogenetic tree , bacteria , gene , genetics , sewage treatment , anatomy , engineering , waste management
The bacterial community structure of the activated sludge from a 25 million-gal-per-day industrial wastewater treatment plant was investigated using rRNA analysis. 16S ribosomal DNA (rDNA) libraries were created from three sludge samples taken on different dates. Partial rRNA gene sequences were obtained for 46 rDNA clones, and nearly complete 16S rRNA sequences were obtained for 18 clones. Seventeen of these clones were members of the beta subdivision, and their sequences showed high homology to sequences of known bacterial species as well as published 16S rDNA sequences from other activated sludge sources. Sixteen clones belonged to the alpha subdivision, 7 of which showed similarity toHyphomicrobium species. This cluster was chosen for further studies due to earlier work onHyphomicrobium sp. strain M3 isolated from this treatment plant. A nearly full-length 16S rDNA sequence was obtained fromHyphomicrobium sp. strain M3. Phylogenetic analysis revealed thatHyphomicrobium sp. strain M3 was 99% similar toHyphomicrobium denitrificans DSM 1869T inHyphomicrobium cluster II. Three of the cloned sequences from the activated sludge samples also grouped with those ofHyphomicrobium cluster II, with a 96% sequence similarity to that ofHyphomicrobium sp. strain M3. The other four cloned sequences from the activated sludge sample were more closely related to those of theHyphomicrobium cluster I organisms (95 to 97% similarity). Whole-cell fluorescence hybridization of microorganisms in the activated sludge with genus-specificHyphomicrobium probe S-G-Hypho-1241-a-A-19 enhanced the visualization ofHyphomicrobium and revealed thatHyphomicrobium appears to be abundant both on the outside of flocs and within the floc structure. Dot blot hybridization of activated sludge samples from 1995 with probes designed forHyphomicrobium cluster I andHyphomicrobium cluster II indicated thatHyphomicrobium cluster II-positive 16S rRNA dominated overHyphomicrobium cluster I-positive 16S rRNA by 3- to 12-fold.Hyphomicrobium 16S rRNA comprised approximately 5% of the 16S rRNA in the activated sludge.