Bioaugmentation of sequencing batch reactors for biological phosphorus removal: comparative rRNA sequence analysis and hybridization with oligonucleotide probes

Abstract

Four laboratory-scale sequencing batch reactors (SBRs) were operated to evaluate whether bioaugmentation with Acinetobacter spp. can be used to improve start-up and performance of enhanced biological phosphorus removal (EBPR) systems. Two of the SBRs were bioaugmented during start-up by adding pure cultures of Acinetobacter spp., the third reactor received an amendment of activated sludge from a laboratory-scale EBPR system, and the fourth reactor, receiving no amendment, served as a control. Various chemical parameters were measured to monitor the performance of the four SBRS. Oligonucleotide probes of nested phylogenetic specificity were designed to quantify the contribution of Acinetobacter to EBPR. The probes were characterized for use in quantitative membrane hybridizations and fluorescent in situ hybridizations. Data from hybridizations with samples collected from the SBRs show declining levels of Acinetobacter spp. over the experiment. All four reactors achieved significant phosphorus removal and 90% nitrification after three days of operation. The results do not show a positive correlation between levels of Acinetobacter and successful EBPR.

Phosphorus removal characteristics of granular and flocculent sludge in SBR

“…This clearly indicated that the more dominant microbial species existed in the flocs system. Meanwhile, β-proteobacterium was widely reported to be responsible for EBPR (Ahn et al 2002;Bond et al 1999;Crocetti et al 2000;Oerther et al 1998). This result implied that the different sludge morphology could influence dominant species and phosphorus removal efficiency in EBPR.…”

Monitoring Precursor 16S rRNAs of Acinetobacter spp. in Activated Sludge Wastewater Treatment Systems

“…Acinetobacter spp. have been historically important in the study of activated sludge, especially in the area of enhanced biological phosphorus removal (20). Therefore, this genus was selected for further study.…”

“…For example, fluorescence in situ hybridization (FISH) has been used to quantify the biomass of specific filamentous microorganisms in activated sludge using a relationship between the number and length of individual target cells and biomass concentration (10). In addition, membrane hybridizations have been used to measure the activity of microbial populations in foaming activated sludge (11) and in activated sludge systems operated for enhanced biological phosphorus removal (20). Although these approaches may not work for all microbial populations-such as metabolically active microorganisms with low rRNA content (19) and metabolically inactive microorganisms with a high residual rRNA content (25,32)-oligonucleotide hybridization probes targeting rRNA have been used successfully to study the microbial ecology of activated sludge (5).…”

Photoalteration of macrophyte-derived chromophoric dissolved organic matter induces growth of single bacterial populations in a coastal lagoon

“…Briefly, a first hybridisation using the peroxidase-conjugated probe LGC354A (Meier et al, 1999) for low guanine-cytosine (GC) content Grampositive bacteria was done including the catalysed reporter deposition step, but the hybridised filter pieces were not counterstained with DAPI. Instead, they were incubated for 20 min at room temperature in 0.01M HCl to inactivate the horseradish peroxidase and then a second hybridisation was run using the monolabeled S-G-Acin-0652-a-A-18 probe (Oerther et al, 1998) for Acinetobacter spp. conjugated to Cy3.…”