16S Ribosomal RNA Tools Identify an Unexpected Predominance of Paenibacillus-Like Bacteria in an Industrial Activated Sludge System Suffering from Poor Biosolids Separation


Molecular biology tools targeting 16S ribosomal RNA (16S rRNA) were used to identify a predominant bacterial population in a full-scale dairy wastewater activated sludge system suffering from poor biosolids separation. Gram and acridine orange staining indicated that viable, Gram-positive microorganisms were present in samples removed from the influent waste, stream and represented approximately 50% of total cell counts in samples removed from the mixed liquor. Subsequently, the "full-cycle 16S rRNA approach" showed that phylogenetic relatives of Paenibacillus spp., a low guanine-plus-cytosine percent DNA-content, Gram-positive microorganism, represented up to 30% of total 4,6-diamidino-2-phenylindole (DAPI)-stained cell counts in samples of mixed liquor. Although fluorescent in situ hybridizations with 16S rRNA-targeted oligonucleotide hybridization probes identified Paenibacillus-like spp. in samples removed from the influent waste stream, their abundance was less than 10% of total stained cell counts. Results of this study suggest that Paenibacillus-like spp. were present in low abundance in the influent waste stream, increased in relative abundance within the treatment system, and should be examined further as a candidate bacterial population responsible for poor biosolids separation. This study demonstrates that the full-cycle 16S rRNA approach can be used to identify candidate bacterial populations that may be responsible for operational upsets in full-scale activated sludge systems without prior information from cultivation or microscopic analyses.


Civil, Architectural and Environmental Engineering

Keywords and Phrases

16S ribosomal RNA; Activated sludge; Dairy food processing; Paenibacillus spp.; Bacteria; Dyes; Molecular biology; RNA; Wastewater; Wastewater treatment; Activated sludge process; 4',6 diamidino 2 phenylindole; acridine orange; oligonucleotide; RNA 16S; abundance; bacterium; biosolid; phylogenetics; water treatment; bacterium identification; cell count; dairying; fluorescence in situ hybridization; Gram staining; nonhuman; oligonucleotide probe; Paenibacillus; phylogeny; priority journal; RNA analysis; waste water management; Bacillaceae; Dairy Products; Equipment Failure; Food Industry; Industrial Waste; Models; Biological; Bacterial; Ribosomal; 16S; Ultrafiltration; Waste Disposal; Fluid; Water Microbiology; Bacteria (microorganisms); Posibacteria

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Article - Journal

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