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Biodegradation of Methyl tert -Butyl Ether by Co-Metabolism with a Pseudomonas sp. Strain

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ABSTRACT

Co-metabolic bioremediation is supposed to be an impressive and promising approach in the elimination technology of methyl tert-butyl ether (MTBE), which was found to be a common pollutant worldwide in the ground or underground water in recent years. In this paper, bacterial strain DZ13 (which can co-metabolically degrade MTBE) was isolated and named as Pseudomonas sp. DZ13 based on the result of 16S rRNA gene sequencing analysis. Strain DZ13 could grow on n-alkanes (C5-C8), accompanied with the co-metabolic degradation of MTBE. Diverse n-alkanes with different carbon number showed a significant influence on the degradation rate of MTBE and accumulation of tert-butyl alcohol (TBA). When Pseudomonas sp. DZ13 co-metabolically degraded MTBE with n-pentane as the growth substrate, a higher MTBE-degrading rate (Vmax = 38.1 nmol/min/mgprotein, Ks = 6.8 mmol/L) and lower TBA-accumulation was observed. In the continuous degradation experiment, the removal efficiency of MTBE by Pseudomonas sp. Strain DZ13 did not show an obvious decrease after five times of continuous addition.

No MeSH data available.


Related in: MedlinePlus

Kinetics of MTBE oxidation by pure strain DZ13 with n-pentane and n-octane as co-metabolic substrates. The figure shows the average rate of MTBE oxidation by strain DZ13 on n-pentane (filled red circles) or n-octane (filled black squares). All of the experiments were performed in triplicate.
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ijerph-13-00883-f002: Kinetics of MTBE oxidation by pure strain DZ13 with n-pentane and n-octane as co-metabolic substrates. The figure shows the average rate of MTBE oxidation by strain DZ13 on n-pentane (filled red circles) or n-octane (filled black squares). All of the experiments were performed in triplicate.

Mentions: The oxidation of TBA—the first stable metabolite detected in MTBE-degrading pathway—is the limiting step of the mineralization of MTBE. The apparent TBA accumulation during the first period of MTBE oxidation by n-alkane-grown cells indicated that the kinetics of MTBE oxidation could be directly determined by measuring the rates of TBA accumulation. Values of Ks and Vmax for MTBE oxidation were determined for pure DZ13 culture grown on n-pentane and n-octane, respectively, in the presence of MTBE (Figure 2). When cultivated with the equivalent concentration of MTBE and n-alkane with different carbon number (C5 and C8) on the same condition, Pseudomonas sp. DZ13 showed different kinetic parameters. The values for Ks of 6.8 mmol and 17.2 mmol, for Vmax of 38.1 nmol/min/mgprotein and 19.6 nmol/min/mgprotein were determined for Pseudomonas sp. DZ13 grown on n-pentane and n-octane, respectively. The alternative explanation of this phenomenon may be the different aqueous solubility of each n-alkane. The Henry’s Law constants of n-pentane and n-octane were 8.1 × 10−4 M/atm and 3.14 × 10−4 M/atm (at 25 °C), respectively [33]. When incubated with the same initial concentration of n-pentane or n-octane, the higher dissolved quantity of n-pentane facilitated its capture by the DZ13 cells and then induced the transcription of alkane monooxygenase, resulting in the degradation of n-pentane and MTBE.


Biodegradation of Methyl tert -Butyl Ether by Co-Metabolism with a Pseudomonas sp. Strain
Kinetics of MTBE oxidation by pure strain DZ13 with n-pentane and n-octane as co-metabolic substrates. The figure shows the average rate of MTBE oxidation by strain DZ13 on n-pentane (filled red circles) or n-octane (filled black squares). All of the experiments were performed in triplicate.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036716&req=5

ijerph-13-00883-f002: Kinetics of MTBE oxidation by pure strain DZ13 with n-pentane and n-octane as co-metabolic substrates. The figure shows the average rate of MTBE oxidation by strain DZ13 on n-pentane (filled red circles) or n-octane (filled black squares). All of the experiments were performed in triplicate.
Mentions: The oxidation of TBA—the first stable metabolite detected in MTBE-degrading pathway—is the limiting step of the mineralization of MTBE. The apparent TBA accumulation during the first period of MTBE oxidation by n-alkane-grown cells indicated that the kinetics of MTBE oxidation could be directly determined by measuring the rates of TBA accumulation. Values of Ks and Vmax for MTBE oxidation were determined for pure DZ13 culture grown on n-pentane and n-octane, respectively, in the presence of MTBE (Figure 2). When cultivated with the equivalent concentration of MTBE and n-alkane with different carbon number (C5 and C8) on the same condition, Pseudomonas sp. DZ13 showed different kinetic parameters. The values for Ks of 6.8 mmol and 17.2 mmol, for Vmax of 38.1 nmol/min/mgprotein and 19.6 nmol/min/mgprotein were determined for Pseudomonas sp. DZ13 grown on n-pentane and n-octane, respectively. The alternative explanation of this phenomenon may be the different aqueous solubility of each n-alkane. The Henry’s Law constants of n-pentane and n-octane were 8.1 × 10−4 M/atm and 3.14 × 10−4 M/atm (at 25 °C), respectively [33]. When incubated with the same initial concentration of n-pentane or n-octane, the higher dissolved quantity of n-pentane facilitated its capture by the DZ13 cells and then induced the transcription of alkane monooxygenase, resulting in the degradation of n-pentane and MTBE.

View Article: PubMed Central - PubMed

ABSTRACT

Co-metabolic bioremediation is supposed to be an impressive and promising approach in the elimination technology of methyl tert-butyl ether (MTBE), which was found to be a common pollutant worldwide in the ground or underground water in recent years. In this paper, bacterial strain DZ13 (which can co-metabolically degrade MTBE) was isolated and named as Pseudomonas sp. DZ13 based on the result of 16S rRNA gene sequencing analysis. Strain DZ13 could grow on n-alkanes (C5-C8), accompanied with the co-metabolic degradation of MTBE. Diverse n-alkanes with different carbon number showed a significant influence on the degradation rate of MTBE and accumulation of tert-butyl alcohol (TBA). When Pseudomonas sp. DZ13 co-metabolically degraded MTBE with n-pentane as the growth substrate, a higher MTBE-degrading rate (Vmax = 38.1 nmol/min/mgprotein, Ks = 6.8 mmol/L) and lower TBA-accumulation was observed. In the continuous degradation experiment, the removal efficiency of MTBE by Pseudomonas sp. Strain DZ13 did not show an obvious decrease after five times of continuous addition.

No MeSH data available.


Related in: MedlinePlus