Denaturing gradient gel electrophoresis analysis of a methyl tert-butyl ether degrading culture applied in a membrane bioreactor

2002 ◽  
Vol 2 (2) ◽  
pp. 207-212 ◽  
Author(s):  
A. Pruden ◽  
M. Suidan ◽  
J. Morrison ◽  
A. Venosa
Keyword(s):  
Gel Electrophoresis ◽  
Membrane Bioreactor ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Selective Pressure ◽  
Methyl Tert Butyl Ether ◽  
Butyl Ether ◽  
Tert Butyl ◽  
Start Up ◽  
Gradient Gel Electrophoresis ◽  
Dramatic Shift

A membrane bioreactor (MBR) was operated for the removal of methyl tert-butyl ether (MTBE) from water. Although the reactor was seeded with several cultures acclimated to MTBE degradation, a long start-up time was observed. Monitoring of the reactor with denaturing gradient gel electrophoresis (DGGE) revealed a dramatic shift in the MBR culture from the original seed culture, indicating that the membrane had exerted a selective pressure on the culture. The MBR culture was found to be dominated almost entirely by Sphingomonas, belonging to the a-4 subclass of the a-Proteobacteria. Several unique properties of Sphingomonas, including their characteristic outer membrane containing glycosphingolipids, as well as their extreme adeptness at xenobiotic degradation are hypothesized to have aided in their selection in this bioreactor.

Biodegradation of MTBE and BTEX in an aerobic fluidized bed reactor

2003 ◽  
Vol 47 (9) ◽  
pp. 123-128 ◽  
Author(s):  
A. Pruden ◽  
M. Sedran ◽  
M. Suidan ◽  
A. Venosa
Keyword(s):  
Fluidized Bed ◽  
Flow Rate ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Oxygen Demand ◽  
Fluidized Bed Reactor ◽  
Methyl Tert Butyl Ether ◽  
Reactor Performance ◽  
Butyl Ether ◽  
Acclimation Period ◽  
Gradient Gel Electrophoresis

An aerobic fluidized bed reactor (FBR) was operated for the removal of methyl tert-butyl ether (MTBE) and benzene, toluene, ethylbenzene, and p-xylene (BTEX) from water. The reactor was seeded with a mixed culture adapted to MTBE. Granular activated carbon (GAC) was used as the biological attachment medium. Influent MTBE to the reactor was 7.8 mg/L MTBE, with a flow rate of 22.7 L/day, and an empty bed contact time of 1 hour. The acclimation period required was relatively short, about 30 days before reaching an average stable effluent concentration of 18.5 ± 10 μg/L. BTEX was introduced to the feed at an equivalent chemical oxygen demand (COD) as the MTBE at day 225 and was biodegraded spontaneously with no apparent acclimation period required. The average influent of each of the four BTEX compounds was about 2 mg/L, and the range of the average effluent concentrations was 1.4-2.2 μg/L. After achieving 180 days of stable performance with BTEX addition, the total flow rate to the reactor was gradually increased by 20% increments to 160% of the original flow (36.4 L/day). Increases by 20% and 40% had no apparent effect on reactor performance, but increase by 60% required 30 days before effluent quality returned to previous values. Composition of the culture was monitored throughout operation of the reactor using denaturing gradient gel electrophoresis (DGGE). The culture consisted of Flavobacteria-Cytophaga and organisms with high similarity to the known MTBE degrader PM1.

scholarly journals Isolation of Methylophaga spp. from Marine Dimethylsulfide-Degrading Enrichment Cultures and Identification of Polypeptides Induced during Growth on Dimethylsulfide

2007 ◽  
Vol 73 (8) ◽  
pp. 2580-2591 ◽  
Author(s):  
Hendrik Schäfer
Keyword(s):  
Gel Electrophoresis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Large Subunit ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Butyl Ether ◽  
Bacterial Populations ◽  
Enrichment Cultures ◽  
Gradient Gel Electrophoresis ◽  
Insight Into

ABSTRACT Dimethylsulfide (DMS)-degrading enrichment cultures were established from samples of coastal seawater, nonaxenic Emiliania huxleyi cultures, and mixed marine methyl halide-degrading enrichment cultures. Bacterial populations from a broad phylogenetic range were identified in the mixed DMS-degrading enrichment cultures by denaturing gradient gel electrophoresis (DGGE). Sequences of dominant DGGE bands were similar to those of members of the genera Methylophaga and Alcanivorax. Several closely related Methylophaga strains were obtained that were able to grow on DMS as the carbon and energy source. Roseobacter-related populations were detected in some of the enrichment cultures; however, none of the Roseobacter group isolates that were tested were able to grow on DMS. Oxidation of DMS by Methylophaga sp. strain DMS010 was not affected by addition of the inhibitor chloroform or methyl tert-butyl ether, suggesting that DMS metabolism may occur by a route different from those described for Thiobacillus species and other unidentified marine isolates. Addition of DMS and methanethiol to whole-cell suspensions of strain DMS010 induced oxygen uptake when strain DMS010 was grown on DMS but not in cells grown on methanol. The apparent Km s of strain DMS010 for DMS and for methanethiol were 2.1 and 4.6 μM, respectively, when grown on DMS. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the biomass of strain DMS010 and analysis of peptide bands by mass spectrometry techniques and N-terminal sequencing provided the first insight into the identity of polypeptides induced during growth on DMS. These included XoxF, a homolog of the large subunit of methanol dehydrogenase for which a biological role has not been identified previously.

Allelopathic and Medicinal plant. 26. Millettia speciosa

2020 ◽  
Vol 51 (2) ◽  
pp. 125-146
Author(s):  
Nasiruddin Nasiruddin ◽  
Yu Zhangxin ◽  
Ting Zhao Chen Guangying ◽  
Minghui Ji
Keyword(s):  
Community Structure ◽  
Medicinal Plant ◽  
Gel Electrophoresis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Wiener Index ◽  
Pseudomonas Spp ◽  
Evenness Index ◽  
Gradient Gel Electrophoresis ◽  
Rhizosphere Pseudomonas

We grew cucumber in pots in greenhouse for 9-successive cropping cycles and analyzed the rhizosphere Pseudomonas spp. community structure and abundance by PCR-denaturing gradient gel electrophoresis and quantitative PCR. Results showed that continuous monocropping changed the cucumber rhizosphere Pseudomonas spp. community. The number of DGGE bands, Shannon-Wiener index and Evenness index decreased during the 3rd cropping and thereafter, increased up to the 7th cropping, however, however, afterwards they decreased again. The abundance of Pseudomonas spp. increased up to the 5th successive cropping and then decreased gradually. These findings indicated that the structure and abundance of Pseudomonas spp. community changed with long-term cucumber monocropping, which might be linked to soil sickness caused by its continuous monocropping.

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