scholarly journals Effects of pH and Oxygen and Ammonium Concentrations on the Community Structure of Nitrifying Bacteria from Wastewater

1998 ◽  
Vol 64 (10) ◽  
pp. 3584-3590 ◽  
Author(s):  
Alenka Prinčič ◽  
Ivan Mahne ◽  
France Megušar ◽  
Eldor A. Paul ◽  
James M. Tiedje
Keyword(s):  
Community Structure ◽  
Fatty Acid ◽  
Starter Culture ◽  
Treatment Plant ◽  
Acid Methyl Ester ◽  
Ssu Rdna ◽  
Nitrifying Bacteria ◽  
Ammonia Oxidizer ◽  
Ammonium Concentration ◽  
Rdna Sequencing

ABSTRACT Shifts in nitrifying community structure and function in response to different ammonium concentrations (50, 500, 1,000, and 3,000 mg of N liter−1), pH values (pH 6.0, 7.0, and 8.2), and oxygen concentrations (1, 7, and 21%) were studied in experimental reactors inoculated with nitrifying bacteria from a wastewater treatment plant. The abilities of the communities selected for these conditions to regain their original structures after conditions were returned to the original conditions were also determined. Changes in nitrifying community structure were determined by performing an amplified ribosomal DNA (rDNA) restriction analysis of PCR products obtained with ammonia oxidizer-specific rDNA primers, by phylogenetic probing, by small-subunit (SSU) rDNA sequencing, and by performing a cellular fatty acid analysis. Digestion of ammonia-oxidizer SSU rDNA with five restriction enzymes showed that a high ammonium level resulted in a great community structure change that was reversible once the ammonium concentration was returned to its original level. The smaller changes in community structure brought about by the two pH extremes, however, were irreversible. Sequence analysis revealed that the highest ammonium environment stimulated growth of a nitrifier strain that exhibited 92.6% similarity in a partial SSU rRNA sequence to its nearest relative, Nitrosomonas eutropha C-91, although the PCR product did not hybridize with a general phylogenetic probe for ammonia oxidizers belonging to the β subgroup of the classProteobacteria. A principal-component analysis of fatty acid methyl ester data detected changes from the starter culture in all communities under the new selective conditions, but after the standard conditions were restored, all communities produced the original fatty acid profiles.

Resistance of nitrifiers inhabiting activated sludge to ciliate grazing

2010 ◽  
Vol 61 (3) ◽  
pp. 573-580 ◽  
Author(s):  
Agnieszka Pajdak-Stós ◽  
Edyta Fiałkowska ◽  
Janusz Fyda ◽  
Roman Babko
Keyword(s):  
Total Nitrogen ◽  
Treatment Plant ◽  
Grazing Pressure ◽  
Nitrifying Bacteria ◽  
Ammonia Oxidizer ◽  
Ammonia Oxidizing Bacteria ◽  
Protozoan Community ◽  
Nitrite Oxidizing Bacteria ◽  
Green Excitation ◽  
Nitrite Oxidizers

We monitored the succession of nitrifiers in a ne.wly 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-NH4+ removal effectiveness.

Evaluation of the Impact of Fatty Acid Methyl Ester (FAME) Contamination on the Thermal Stability of Jet A

2013 ◽  
Author(s):  
Jr Morris ◽  
Shardo Robert W. ◽  
Higgins James ◽  
Cook Kim ◽  
Tanner Rhonda ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Fatty Acid ◽  
Methyl Ester ◽  
Fatty Acid Methyl Ester ◽  
Acid Methyl Ester ◽  
Acid Methyl ◽  
The Impact ◽  
Thermal Stability Of

scholarly journals Primitive techno-economic study of bio-diesel and bio-active compound production from microalgae

2020 ◽  
Vol 44 (1) ◽  
Author(s):  
Sayeda M. Abdo ◽  
Guzine I. El Diwani ◽  
Kamel M. El-Khatib ◽  
Sanaa A. Abo El-Enin ◽  
Mohammed I. El-Galad ◽  
...  
Keyword(s):  
Active Compound ◽  
Municipal Wastewater ◽  
Scenedesmus Obliquus ◽  
Cetane Number ◽  
Treatment Plant ◽  
Acid Methyl Ester ◽  
Biodiesel Production ◽  
High Rate ◽  
Total Phenolic ◽  
Microscopical Examination

Abstract Background Microalgae cells can be identified as a potential source for new and renewable energy. The economic investigation for biodiesel and bio-active compound production from the microalgae community (Bloom), which are collected from the high rate algal pond (HRAP) constructed to treat municipal wastewater at Zenin wastewater treatment plant, Giza, was the main target of study. Results The microscopical examination showed that Scenedesmus obliquus is the dominant species. The total carotenoids were extracted using jojoba oil and determined by high-performance liquid chromatography (HPLC) to reach 81.44 μg/g. The biodiesel production through acid transesterification reaction recorded 70.6% of fatty acid methyl ester content with high cetane number (44) and low acid value. Such results prove that the obtained biodiesel has better ignition quality. The total phenolic and flavonoid compounds have been derived from the remaining biomass to give 5.36 ± 0.03 and 1.50 ± 0.19 mg/g respectively. Finally, total proteins and carbohydrates content in algal cells were recorded 54.3 and 1.5 mg/g successively Conclusion The preliminary economic evaluation showed that the production of biodiesel and carotenoids from the microalgae growing in municipal wastewater can be considered, as a techno-economic feasible process.

Sign in / Sign up

Export Citation Format

Share Document