scholarly journals Effect of Pyocyanin on a Crude-Oil-Degrading Microbial Community

2004 ◽  
Vol 70 (7) ◽  
pp. 4004-4011 ◽  
Author(s):  
R. Sean Norman ◽  
Peter Moeller ◽  
Thomas J. McDonald ◽  
Pamela J. Morris

ABSTRACT Pseudomonas aeruginosa is an n-alkane degrader that is frequently isolated from petroleum-contaminated sites and produces factors that enhance its competitiveness and survival in many environments. In this study, one such factor, pyocyanin, has been detected in an oil-degrading culture containing P. aeruginosa and is a redox-active compound capable of inhibiting microbial growth. To examine the effects of pyocyanin further, an oil-degrading culture was grown with and without 9.5 μM pyocyanin and microbial community structure and oil degradation were monitored for 50 days. Denaturing gradient gel electrophoresis (DGGE) analysis of cultures revealed a decrease in the microbial community diversity in the pyocyanin-amended cultures compared to that of the unamended cultures. Two members of the microbial community in pure culture exhibited intermediate and high sensitivities to pyocyanin corresponding to intermediate and low levels of activity for the antioxidant enzymes catalase and superoxide dismutase, respectively. Another member of the community that remained constant in the DGGE gels over the 50-day culture incubation period exhibited no sensitivity to pyocyanin, corresponding to a high level of catalase and superoxide dismutase when examined in pure culture. Pyocyanin also affected the overall degradation of the crude oil. At 50 days, the culture without pyocyanin had decreased polycyclic aromatic hydrocarbons compared to the pyocyanin-amended culture, with a specific reduction in the degradation of dibenzothiophenes, naphthalenes, and C29 and C30 hopanes. This study demonstrated that pyocyanin influenced the diversity of the microbial community and suggests the importance of understanding how interspecies interactions influence the degradation capability of a microbial community.

2013 ◽  
Vol 59 (10) ◽  
pp. 694-700 ◽  
Author(s):  
Xinyu Li ◽  
Xu Li ◽  
Jian Wang ◽  
Xiujuan Wang ◽  
Jian Sun ◽  
...  

Indigenous Mycobacterium communities play an important role in the degradation of polycyclic aromatic hydrocarbons (PAHs), but little is known about Mycobacterium distribution in situ at PAH-contaminated sites. In this study, the diversity and distribution of Mycobacterium communities were investigated in sediments and soils at sites upstream, midstream, and downstream of an oil-sewage irrigation channel, using denaturing gradient gel electrophoresis (DGGE). The results show that heavy PAH contamination in upstream sites negatively affected Mycobacterium community diversity compared with midstream and downstream sites in all 3 sample types (sediments, corn field soils, and rice field soils). There was a correlation between the distribution of Mycobacterium communities and PAH contamination, as indicated by canonical correspondence analysis. Mycobacterium diversity and distribution was found to vary between the 3 sample types.


2002 ◽  
Vol 46 (11-12) ◽  
pp. 93-98 ◽  
Author(s):  
S. Yoshie ◽  
N. Noda ◽  
T. Miyano ◽  
S. Tsuneda ◽  
A. Hirata ◽  
...  

The metallurgic wastewater generated from the processes of recovering precious metals from industrial wastes contains high concentrations of nitrogen compounds such as ammonia and nitric acid and of salts such as sodium chloride and sodium sulfate. Biological nitrogen removal from this wastewater was attempted by a circulating bioreactor system equipped with an anoxic packed bed and an aerobic fluidized bed. The anoxic packed bed of this system was found to effectively remove nitrite and nitrate from the wastewater by denitrification at a removal ratio of 97%. As a result of denitrification activity tests at various NaCl concentrations, the sludge obtained from the anoxic packed bed exhibited accumulation of nitrite at 5.0 and 8.4% NaCl concentrations, suggesting that the reduction of nitrite is the key step in the denitrification pathway under hypersaline conditions. The microbial community analysis by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S ribosomal DNA (rDNA) fragments revealed that the community diversity varied in accordance with water temperature, nitrate-loading rate and ionic strength. When particular major DGGE bands were excised, reamplified and directly sequenced, the dominant species in the anoxic packed bed were affiliated with the beta and gamma subclasses of the class Proteobacteria such as Alcaligenes defragrans and Pseudomonas spp., respectively.


2004 ◽  
Vol 70 (4) ◽  
pp. 2263-2270 ◽  
Author(s):  
William E. Holben ◽  
Kevin P. Feris ◽  
Anu Kettunen ◽  
Juha H. A. Apajalahti

ABSTRACT Effectively and accurately assessing total microbial community diversity is one of the primary challenges in modern microbial ecology. This is particularly true with regard to the detection and characterization of unculturable populations and those present only in low abundance. We report a novel strategy, GC fractionation combined with denaturing gradient gel electrophoresis (GC-DGGE), which combines mechanistically different community analysis approaches to enhance assessment of microbial community diversity and detection of minority populations of microbes. This approach employs GC fractionation as an initial step to reduce the complexity of the community in each fraction. This reduced complexity facilitates subsequent detection of diversity in individual fractions. DGGE analysis of individual fractions revealed bands that were undetected or only poorly represented when total bacterial community DNA was analyzed. Also, directed cloning and sequencing of individual bands from DGGE lanes corresponding to individual G+C fractions allowed detection of numerous phylotypes that were not recovered using a traditional random cloning and sequencing approach.


2001 ◽  
Vol 43 (1) ◽  
pp. 77-82 ◽  
Author(s):  
O.-C. Chan ◽  
W.-T. Liu ◽  
H. H. Fang

The microbial community structure of granular sludge from an upflow anaerobic sludge blanket (UASB) reactor treating brewery effluent was studied by denaturing gradient gel electrophoresis (DGGE). Twelve major bands were observed in the DGGE fingerprint for the Bacteria domain and four bands for the Archaea domain. Of the bacterial bands observed, six were successfully purified and sequenced. Among them, three were related to the gram-positive low G+C group, one to the Delta subclass of the Proteobacteria, one to the Gamma subclass, and one to the Cytophaga group with no close related sequence. The 16S rRNA sequences of the four archaeal bands were closely associated with Methanosaeta concilii and Methanobacterium formicum.


2014 ◽  
Vol 700 ◽  
pp. 519-524 ◽  
Author(s):  
Jie Liu ◽  
Yan Li Ding ◽  
Mark Bartlam ◽  
Ying Ying Wang

Underground water is directly used as drinking water in most rural areas of developing countries due to limitations in infrastructure. As an important indicator of drinking water quality, however, microbial quality has been largely ignored for a long time. Microbial quality poses a great threat to the safety of underground drinking water, especially in rural areas. The current study compared microbial abundance and community structure of three different water sources, i.e. underground water, Poyang Lake and Hai River, combined with flow cytometry (FCM) and denaturing gradient gel electrophoresis (DGGE). FCM results showed that the bacterial concentration of underground water is the lowest (1.037×106cell/ml) of the three water sources, but still approximates that of the Poyang Lake. The removal rate of bacteria after filtration through a 0.45μm-pore-size filter is 98.16% in underground water. The removal rate for Poyang Lake and Hai River is much lower (i.e. 66.57% and 74.17% respectively). DGGE profiles demonstrated that the microbial community structure in underground water shares higher similarity to Poyang Lake (51.0% and 53.1% similarity for bacteria and fungi respectively) than Hai River. The microbial diversity index (i.e. Shannon-Weaver index) for bacteria and fungi are 2.906 and 2.847 respectively in underground water, which is lower than in Poyang Lake. The evenness (i.e. Simpson index) of groundwater was lowest among the three water sources tested. The results suggested that groundwater has a complex microbial community and hence it is critical to apply necessary hygienic barriers to remove microbes for the safety of underground drinking water.


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