‘Morphological shifts’ in filamentous bacteria isolated from activated sludge processes

Ramothokang, TR; Naidoo, D.; Bux, Faizal

doi:10.1007/s11274-005-9113-1

Cited by 7 publications

(5 citation statements)

References 23 publications

(22 reference statements)

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“…This finding is contrary to Pike and Curds' computer simulation of microorganism succession (Pike & Curds 1971 It seems probable that grazer pressure can enhance such morphology as has been shown in aquatic bacteria (Hahn & Hö fle 2001). It has also been shown that filamentous bacteria from activated sludge are extremely plastic when isolated and grown in pure culture (Ramothokang et al 2006). The authors showed that three different filamentous bacteria changed their form to single cocci or rod-shaped cells when isolated on solid medium.…”

Section: Discussionmentioning

confidence: 82%

“…The authors showed that three different filamentous bacteria changed their form to single cocci or rod-shaped cells when isolated on solid medium. They assumed that it was a reaction to the change in environmental conditions (Ramothokang et al 2006). If bacteria can so radically change their morphology in response to habitat conditions, it is also highly probable that in their natural habitat, they can shift morphology to protect themselves against grazers.…”

Section: Discussionmentioning

confidence: 99%

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Resistance of nitrifiers inhabiting activated sludge to ciliate grazing

Pajdak‐Stós

Fiałkowska

Fyda

et al. 2010

Water Science and Technology

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We monitored the succession of nitrifiers in a newly opened wastewater treatment plant for five weeks. After the first distinct decrease in total nitrogen, we began monitoring the appearance, size and number of nitrifying bacteria colonies using the fluorescence in situ hybridization (FISH) method. Ammonia oxidizing bacteria (AOB) colonies were visualized under green excitation as red, and nitrite oxidizing bacteria (NOB) colonies were visualized under blue excitation as green. The changes in protozoan community were monitored simultaneously. Ciliates were divided into four functional groups: predatory, bacterivorous free-swimming, bacterivorous crawling, and sessile. The results showed that at the time of the first distinct total nitrogen decrease, the mean length of both AOB and NOB were relatively low, but the colonies, especially those of nitrite oxidizers, were abundant. In time, the distribution of ammonia oxidizer colonies shifted towards larger sizes, but their quantity decreased. In the case of nitrite oxidizers, a similar trend was noticeable but less pronounced. These changes corresponded with an increasing number of crawling bacterivorous ciliates dominated by the "scavenger" genus Aspidisca. The increasing size of nitrifier colonies may have been due to the growing grazing pressure from crawling bacterivorous ciliates. The strong grazing pressure did not negatively affect N-NH(4)(+) removal effectiveness.

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Section: Discussionmentioning

confidence: 82%

Section: Discussionmentioning

confidence: 99%

Resistance of nitrifiers inhabiting activated sludge to ciliate grazing

Pajdak‐Stós

Fiałkowska

Fyda

et al. 2010

Water Science and Technology

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“…For example some filamentous organisms are able to revert to a unicellular form at some stages of their lifecycle (Ramothokang et al, 2006). Other morphological groups such as 'Eikelboom Type 1863' have been shown to comprise of several unrelated taxa (Seviour et al, 1997) (therefore a confidence and utility score 3).…”

Section: Microscopy Based Ecologymentioning

confidence: 99%

A review of practical tools for rapid monitoring of membrane bioreactors

2016

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The production of high quality effluent from membrane bioreactors (MBRs) arguably requires less supervision than conventional activated sludge (CAS) processes. Nevertheless, the use of membranes brings additional issues of activated sludge filterability, cake layer formation and membrane fouling. From a practical standpoint, process engineers and operators require simple tools which offer timely information about the biological health and filterability of the mixed liquor as well as risks of membrane fouling. To this end, a range of analytical tools and biological assays are critically reviewed from this perspective. This review recommends that Capillary Suction Time (CST) analysis along with Total Suspended and Volatile Solids (TSS/VSS) analysis is used daily. For broad characterisation, total carbon and nitrogen analysis offer significant advantages over the commonly used chemical and biological oxygen demand (COD/BOD) analyses. Of the technologies for determining the vitality of the microbial biomass the most robust and reproducible, are the second generation adenosine-5'-triphosphate (ATP) test kits. Extracellular polymer concentrations are best monitored by measurement of turbidity after centrifugation. Taken collectively these tools can be used routinely to ensure timely intervention and smoother operation of MBR systems.

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“…Isolation of filamentous bacteria, however, is a difficult task. The majority of filamentous bacteria are overgrown by rapid growers (Ramothokang et al, 2006). Therefore, the aim of this research was to isolate, identify, and characterize the predominant filamentous bacteria observed in foaming sludge from a South African wastewater treatment plant.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Nocardia farcinica, a Filamentous Bacterium Isolated from Foaming Activated Sludge Samples

Naidoo

Kumari

Bux

2011

Water Environment Research

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The identification and ch;iracterization of filamentous bacteria and their association with specific plant operating conditions and influent characteristics has been hampered because of morphological variations and differences between process configurations. A study was conducted to isolate and characterize the predominant filamentous bacteria observed in a foaming activated sludge treatment plant. The predominant foam-forming filament was isolated and characterized using microscopic, biochemical and molecular techniques. The phylogenetic analysis of the 16S rRNA gene confirmed that it was Nocardia farcinica, a typical filamentous foam-foaming pathogenic bacterium which is not widely reported outside of South Africa. The bacterium used a variety of substrates for its growth and showed greater affinity to larger and slowly biodegradable compounds. The N. farcinica grew well at temperatures ranging from 12 to 30 C in R2A medium and with a pH ranging from 5.5 to 8.0 and an NaCl concentration of 1 to 5%. This range of conditions shows that A' , farcinica can withstand extreme conditions, which results in its proliferation in foaming samples. Water Environ. Res., 83, 527 (2011).

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‘Morphological shifts’ in filamentous bacteria isolated from activated sludge processes

Cited by 7 publications

References 23 publications

Resistance of nitrifiers inhabiting activated sludge to ciliate grazing

Resistance of nitrifiers inhabiting activated sludge to ciliate grazing

A review of practical tools for rapid monitoring of membrane bioreactors

Characterization of Nocardia farcinica, a Filamentous Bacterium Isolated from Foaming Activated Sludge Samples

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