Microbial Ecology of Activated Sludge I. Dominant Bacteria

Applied microbiology 10/1964; 12(5):412-7.
Source: PubMed


Over 300 bacterial strains were isolated from seven samples of activated sludge by plating on sewage agar. Gram-negative bacteria of the genera Zoogloea and Comamonas predominated. Many isolates (51%) showed sudanophilic inclusions of poly-beta-hydroxybutyric acid, whereas 34% accumulated iodophilic material on media containing starch. A large number required either vitamins or amino acids, or both, for growth. None of the isolates tested for their ability to bring about changes in autoclaved sewage produced an effluent comparable in quality to the activated sludge control, although the Zoogloea did produce activated sludgelike flocs. A study of 150 bacterial strains isolated from raw sewage revealed that they differed from the sludge isolates in several respects. Coliforms, which constitute nearly a quarter of the sewage isolates, were rarely encountered in sludge.

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    • "It contains a highly complex mixture of microbial populations whose composition has been intensively studied in the past decades. By applying culture-dependent methods many species have been isolated from activated sludge (Dias and Bhat, 1964; Prakasam and Dondero, 1967; Benedict and Carlson, 1971). However, a great majority cannot be obtained by conventional techniques (Wagner et al., 1993) and, consequently, current molecular techniques such as sequence analysis of 16S rRNA gene clone libraries (Snaidr et al., 2011), fingerprinting methods such as denaturing gradient gel electrophoresis (DGGE; Boon et al., 2002), thermal gradient gel electrophoresis (TGGE; Eichner et al., 1964) and terminal restriction fragment length polymorphism (Saikaly et al., 2011) along with fluorescence in situ hybridization (FISH) have been employed in wastewater microbiology to analyse and compare the microbial structure of activated sludge. "
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    ABSTRACT: The bacterial community composition of activated sludge from a wastewater treatment plant (Almería, Spain) with the particularity of using seawater was investigated by applying 454-pyrosequencing. The results showed that Deinococcus-Thermus, Proteobacteria, Chloroflexi and Bacteroidetes were the most abundant retrieved sequences, while other groups, such as Actinobacteria, Chlorobi, Deferribacteres, Firmicutes, Planctomycetes, Spirochaetes and Verrumicrobia were reported at lower proportions. Rarefaction analysis showed that very likely the diversity is higher than what could be described despite most of the unknown microorganisms probably correspond to rare diversity. Furthermore, the majority of taxa could not be classified at the genus level and likely represent novel members of these groups. Additionally, the nitrifiers in the sludge were characterized by pyrosequencing the amoA gene. In contrast, the nitrifying bacterial community, dominated by the genera Nitrosomonas, showed a low diversity and rarefaction curves exhibited saturation. These results suggest that only a few populations of low abundant but specialized bacteria are responsible for removal of ammonia in these saline wastewater systems.
    Full-text · Article · Apr 2013 · Microbial Biotechnology
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    • "C. testosteroni is a Gram-negative aerobic bacteria that is found in diverse environments (Ma et al. 2009). Bacteria of the genus Comamonas are predominant in activated sewage sludge (Dias and Bhat 1964) and are defined by a poor ability to use carbohydrates; instead carbon is derived from molecules such as testosterone and other cyclic hydrocarbons (Linares et al. 2008; Horinouchi et al. 2010). C. testosteroni has recently been identified as an opportunistic human pathogen that has been found in various hospital infections including meningitis (Arda et al. 2003; Jin et al. 2008), bacteremia (Gul et al. 2007) and endophthalmitis (Reddy et al. 2009). "
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    ABSTRACT: Glycosaminoglycans (GAGs) are linear hexosamine-containing polysaccharides. These polysaccharides are synthesized by some pathogenic bacteria to form an extracellular coating or capsule. This strategy forms the basis of molecular camouflage since vertebrates possess naturally occurring GAGs that are essential for life. A recent sequence database search identified a putative protein from the opportunistic pathogen Comamonas testosteroni that exhibits similarity with the Pasteurella multocida GAG synthase PmHS1, which is responsible for the synthesis of a heparosan polysaccharide capsule. Initial supportive evidence included glucuronic acid (GlcUA)-containing polysaccharides extracted from C. testosteroni KF-1. We describe here the cloning and analysis of a novel Comamonas GAG synthase, CtTS. The GAG produced by CtTS in vitro consists of the sugars d-GlcUA and N-acetyl-D-glucosamine, but is insensitive to digestion by GAG digesting enzymes, thus has distinct glycosidic linkages from vertebrate GAGs. The backbone structure of the polysaccharide product [-4-D-GlcUA-α1,4-D-GlcNAc-α1-](n) was confirmed by nuclear magnetic resonance. Therefore, this novel GAG, testosteronan, consists of the same sugars as the biomedically relevant GAGs heparosan (N-acetyl-heparosan) and hyaluronan but may have distinct properties useful for future medical applications.
    Preview · Article · May 2011 · Glycobiology
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    • "Successful integration of activated sludge as the biocomponent in an FM-BOD assay would overcome the timeconsuming and expensive requirement of culturing several strains of bacteria to produce a mixed consortia biocatalyst. Activated sludge also represents the ideal biocatalyst for the BOD 5 assay as it contains a diverse community of heterotrophs from a number of functional groups that will ensure a high proportion of biodegradation occurs (Dias and Bhat, 1964, 1965; Hiraishi et al., 1989). In addition, activated sludge can be readily sampled from most WWTPs and an activated sludge FM-BOD assay would be far more relevant to the wastewater industry, as measurements of the industrial effluent BODs, would be representative of the BOD loading exerted upon the plant activated sludge ultimately treating the same wastewater. "
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    ABSTRACT: Activated sludge was successfully incorporated as the biocatalyst in the fast, ferricyanide-mediated biochemical oxygen demand (FM-BOD) bioassay. Sludge preparation procedures were optimized for three potential biocatalysts; aeration basin mixed liquor, aerobic digester sludge and return activated sludge. Following a 24h starving period, the return activated sludge and mixed liquor sludges reported the highest oxidative degradation of a standard glucose/glutamic acid (GGA) mixture and the return activated sludge also recorded the lowest endogenous FM-respiration rate. Dynamic working ranges up to 170 mg BOD(5)L(-1) for OECD standard solutions and 300mg BOD(5)L(-1) for GGA were obtained. This is a considerable improvement upon the BOD(5) standard assay and most other rapid BOD techniques. Time-series ferricyanide-mediated oxidation of the OECD(170) standard approached that of the GGA(198) standard after 3-6h. This is noteworthy given the OECD standard is formulated as a synthetic sewage analogue. A highly significant correlation with the BOD(5) standard method (n=35, p<0.001, R=0.952) was observed for a wide diversity of real wastewater samples. The mean degradation efficiency was indistinguishable from that observed for the BOD(5) assay. These results demonstrate that the activated sludge FM-BOD assay may be used for simple, same-day BOD analysis of wastewaters.
    Full-text · Article · Dec 2010 · Water Research
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