• Title/Summary/Keyword: microbial engineering

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Differentiation in Nitrogen-Converting Activity and Microbial Community Structure between Granular Size Fractions in a Continuous Autotrophic Nitrogen Removal Reactor

  • Qian, Feiyue;Chen, Xi;Wang, Jianfang;Shen, Yaoliang;Gao, Junjun;Mei, Juan
    • Journal of Microbiology and Biotechnology
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    • v.27 no.10
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    • pp.1798-1807
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    • 2017
  • The differentiations in nitrogen-converting activity and microbial community structure between granular size fractions in a continuous completely autotrophic nitrogen removal over nitrite (CANON) reactor, having a superior specific nitrogen removal rate of $0.24g/(g\;VSS{\cdot}h)$, were investigated by batch tests and high-throughput pyrosequencing analysis, respectively. Results revealed that a high dissolved oxygen concentration (>1.8 mg/l) could result in efficient nitrite accumulation with small granules (0.2-0.6 mm in diameter), because aerobic ammonium-oxidizing bacteria (genus Nitrosomonas) predominated therein. Meanwhile, intermediate size granules (1.4-2.0 mm in diameter) showed the highest nitrogen removal activity of $40.4mg/(g\;VSS{\cdot}h)$ under sufficient oxygen supply, corresponding to the relative abundance ratio of aerobic to anaerobic ammonium-oxidizing bacteria (genus Candidatus Kuenenia) of 5.7. Additionally, a dual substrate competition for oxygen and nitrite would be considered as the main mechanism for repression of nitrite-oxidizing bacteria, and the few Nitrospira spp. did not remarkably affect the overall performance of the reactor. Because all the granular size fractions could accomplish the CANON process independently under oxygen limiting conditions, maintaining a diversity of granular size would facilitate the stability of the suspended growth CANON system.

Measurement of Biological Activity in Pilot Scale Dyeing Wastewater Process by Using Respirometer (호흡률 측정기를 이용한 파일럿 스케일 염색폐수처리 장치에서의 생물학적 활성 측정)

  • Jeon Hyun Hee;Choi Kwang Keun;Yoon In Jun;Lee Jin Won
    • KSBB Journal
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    • v.19 no.5
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    • pp.390-393
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    • 2004
  • Oxygen uptake rate (OUR) was used as an indicator of microbial activity. In this study OUR at dyeing wastewater in the pilot plant was monitored to examine biological activity. Correlation between inlet COD concentration and maximum OUR showed that maximum OUR was proportional to inlet COD concentration. Changes in the OUR values reflected the changing waste load in the reactor. Consequently, OUR can be used to estimate biological activity of inlet COD concentration. This study showed that biodegradable COD at dyeing wastewater could be calculated from OUR and yield coefficient. Non-biodegradable COD was able to be calculated from a difference between initial COD concentration and biodegradable COD.

Linkage Between Biodegradation of Polycyclic Aromatic Hydrocarbons and Phospholipid Profiles in Soil Isolates

  • Nam, Kyoung-Phile;Moon, Hee-Sun;Kim, Jae-Young;Kukor, Jerome-J.
    • Journal of Microbiology and Biotechnology
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    • v.12 no.1
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    • pp.77-83
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    • 2002
  • A bacterial consortium capable of utilizing a variety of polycyclic aromatic hydrocarbons has been isolated from a former manufactured gas plant site. The consortium consisted of four members including Arthrobacter sp., Burkholderia sp., Ochrobacterium sp., and Alcaligenes sp., which were identified and characterized by the patterns of fatty acid methyl esters (FAME analysis) and carbon source utilization (BIOLOG system). With the individual members, the biodegradation characteristics of aromatic hydrocarbons depending on different growth substrates were determined. FAME analyses demonstrated that microbial fatty acid profiles changed to significant extents in response to different carbon sources, and hence, such shift profiles may be informative to characterize the biodegradation potential of a bacterium or microbial community.

Pyrosequencing-Based Analysis of the Bacterial Community in Korean Traditional Seafood, Ojingeo Jeotgal

  • Jung, Jaejoon;Choi, Sungjong;Jeon, Che Ok;Park, Woojun
    • Journal of Microbiology and Biotechnology
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    • v.23 no.10
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    • pp.1428-1433
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    • 2013
  • Jeotgal fermentation is dependent upon a diverse microbial community, although a detailed understanding of its microbial composition is limited to a relatively small number of jeotgal. Pyrosequencing-based bacterial community analysis was performed in fermented squid, ojingeo jeotgal. Leuconostoc was identified as the predominant bacterial genus, with Bacillus and Staphylococcus also accounting for a large proportion of the bacterial community. Phylogenetic analysis with 16S rRNA genes of Leuconostoc type species indicated that L. citreum- and L. holzapfelii-like strains could be the major Leuconostoc strains in jeotgal. High concentrations of NaCl were thought to be an important factor determining the makeup of the bacterial community in the fermented squid; however, a genomic survey with osmotic stress-related genes suggests the existence of more complex factors selecting the dominant bacterial species in fermented squid.