Microbial Ecology of Activated Sludge I. Dominant Bacteria

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

ABSTRACT 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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    • "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.
    Glycobiology 05/2011; 21(10):1331-40. DOI:10.1093/glycob/cwr072 · 3.14 Impact Factor
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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.
    Water Research 12/2010; 44(20):5981-8. DOI:10.1016/j.watres.2010.07.042 · 5.32 Impact Factor
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    • "William T. Stringfellow and Lisa Alvarez-Cohen 2538 activated sludge samples (Table 2). Perhaps a more realistic microbial model for activated sludge MLSS would consist of a mixture of Gram positive bacteria , such as Rhodococcus rhodochrous and Gram negative bacteria such as Pseudomonas stutzeri, as MLSS is typically composed of both Gram positive and Gram negative organisms (Dias and Bhat, 1964; Taber, 1976; Lemmer and Kroppenstedt, 1984). "
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    ABSTRACT: Petroleum refinery wastewater containing polynuclear aromatic hydrocarbons (PAHs) are typically treated by biological processes in the United States. PAHs are recalcitrant, hydrophobic compounds and sorption to biological solids may be a significant mechanism for the removal of PAHs from refinery wastewater. The goal of this research was to investigate PAH sorption by bacterial biomass and examine the relationship between PAH biosorption and biodegradation. In this study, phenanthrene was used as a model PAH for biosorption studies and pyrene and fluoranthene were used as model compounds in biodegradation studies. It was found that phenanthrene biosorption varied with bacterial genus and species. Bacteria with the highest sorption capacity (Kp) belong to the Nocardioforms, organisms that often cause solids separation problems in activated sludge plants. Consequently, blooms of these difficult to settle organisms in refinery treatment plants could exasperate PAH releases to the environment. The measured sorption capacities were reproducible and appeared to represent surface sorption, based on the apparent competition between naphthalene and phenanthrene for sorption sites. Based on a comparison of Kp values, pure bacterial cultures can serve as valid models of biosorption by activated sludge MLSS. Finally it was found that PAH sequestration by high Kp, non-degraders has a significant impact on PAH biodegradation. The results of this study suggest that although biosorption can decrease the rate of PAH biodegradation in the short term, it can also result in the removal of PAHs from the wastewater and PAH retention in the treatment system where it may be ultimately biodegraded. This research improves our understanding of processes contributing to PAH degradation in petroleum refinery wastewater treatment plants.
    Water Research 10/1999; 33(11-33):2535-2544. DOI:10.1016/S0043-1354(98)00497-7 · 5.32 Impact Factor
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