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High-throughput screening for a moderately halophilic phenol-degrading strain and its salt tolerance response.

Lu ZY, Guo XJ, Li H, Huang ZZ, Lin KF, Liu YD - Int J Mol Sci (2015)

Bottom Line: Bacterial enrichments were cultivated in 48 deep well microplates instead of shake flasks or tubes.Measurement of phenol concentrations was performed in 96-well microplates instead of using the conventional spectrophotometric method or high-performance liquid chromatography (HPLC).PCR detection of the functional genes suggested that the largest subunit of multicomponent phenol hydroxylase (LmPH) and catechol 1,2-dioxygenase (C12O) were active in the phenol degradation process.

View Article: PubMed Central - PubMed

Affiliation: State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China. lzy1009a@163.com.

ABSTRACT
A high-throughput screening system for moderately halophilic phenol-degrading bacteria from various habitats was developed to replace the conventional strain screening owing to its high efficiency. Bacterial enrichments were cultivated in 48 deep well microplates instead of shake flasks or tubes. Measurement of phenol concentrations was performed in 96-well microplates instead of using the conventional spectrophotometric method or high-performance liquid chromatography (HPLC). The high-throughput screening system was used to cultivate forty-three bacterial enrichments and gained a halophilic bacterial community E3 with the best phenol-degrading capability. Halomonas sp. strain 4-5 was isolated from the E3 community. Strain 4-5 was able to degrade more than 94% of the phenol (500 mg · L(-1) starting concentration) over a range of 3%-10% NaCl. Additionally, the strain accumulated the compatible solute, ectoine, with increasing salt concentrations. PCR detection of the functional genes suggested that the largest subunit of multicomponent phenol hydroxylase (LmPH) and catechol 1,2-dioxygenase (C12O) were active in the phenol degradation process.

No MeSH data available.


Related in: MedlinePlus

Biodegradation of phenol by Halomonas sp. strain 4-5 at different salt concentrations with 500 mg·L−1 phenol. The experiments were carried out in 125-mL serum bottles containing 50 mL of mineral salts medium (MSM) with 5% inoculation. PH stands for phenol concentration, and OD stands for optical density. Numbers correspond to NaCl concentration. Data are the mean of triplicate bottles, and bars indicate ± the standard deviation.
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ijms-16-11834-f006: Biodegradation of phenol by Halomonas sp. strain 4-5 at different salt concentrations with 500 mg·L−1 phenol. The experiments were carried out in 125-mL serum bottles containing 50 mL of mineral salts medium (MSM) with 5% inoculation. PH stands for phenol concentration, and OD stands for optical density. Numbers correspond to NaCl concentration. Data are the mean of triplicate bottles, and bars indicate ± the standard deviation.

Mentions: The effects of salinity on the growth and phenol degradation of strain 4-5 was investigated in mineral salts medium (MSM) containing 500 mg·L−1 phenol and various concentration of NaCl (Figure 6). Halomonas sp. strain 4-5 showed optimal growth and phenol degradation at 5% NaCl. The strain was able to remove phenol after 68 h when cultivated in medium containing 500 mg·L−1 phenol and 3%, 5%, 8%, 10% and 12% NaCl. The removal rates were 96.2%, 99.8%, 98.9%, 94.7% and 86.3%, respectively. When the salinity increased to more than 12%, the phenol removal rate decreased significantly. A few studies have already reported successful phenol removal under salt conditions; most of these investigated the degradation ability in fixed salinity or with a narrow range of salinities. Peyton et al. [21] enriched five bacterial cultures from diverse saline environments capable of degrading phenol from 50 mg·L−1 to lower than 2 mg·L−1 at 10% (w/v) NaCl. Bonfá et al. [22] isolated three halophilic strains from different saline environments identified as Halomonas organivorans, Arhodomonas aquaeolei and Modicisalibacter tunisiensis that could grow in a medium with 10% salinity and 280 mg·L−1 phenol. Kobayashi et al. [23] separated three marine bacteria identified as Acinetobacter spp. EBR01, EBR02 and C. marina EBR04 from marine environments that could degrade 100 mg·L−1 phenol at 3.7% salinity. However, these studies only investigated phenol degradation under a fixed salinity. Gayathri and Vasudevan [24] examined the phenol degradation ability of a moderately halophilic bacterial consortium, which could degrade 50 mg·L−1 phenol with a removal rate of 95%, 99%, 93% and 89% when the NaCl concentration was 3%, 5%, 7% and 10%, respectively. By comparison, the salt tolerance range of the strain obtained in this study was up to 3%–12%. A detailed investigation of the effects of various salinities on growth and phenol degradation of the strain was reported. Additionally, the strain could degrade 500 mg·L−1 phenol over 94% at 3%–10% NaCl. Compared with previous reports, strain 4-5 obtained in this study had the advantage not only of a high removal rate, but also tolerance to a high salinity and initial concentration of phenol, which may contribute to phenol removal in the biological treatment of saline wastewater. Strain 4-5 was screened from the community E3, which was identified as having the best phenol-degrading capability among the 43 bacterial enrichments cultivated in the high-throughput screening system. The strain obtained from this high-throughput system had a unique phenol-degrading character compared to previous reported strains using the conventional screening techniques. The high-throughput system had the advantages not only of increasing the number of the screened samples, but also of improving the phenol-degrading ability of the gained strains.


High-throughput screening for a moderately halophilic phenol-degrading strain and its salt tolerance response.

Lu ZY, Guo XJ, Li H, Huang ZZ, Lin KF, Liu YD - Int J Mol Sci (2015)

Biodegradation of phenol by Halomonas sp. strain 4-5 at different salt concentrations with 500 mg·L−1 phenol. The experiments were carried out in 125-mL serum bottles containing 50 mL of mineral salts medium (MSM) with 5% inoculation. PH stands for phenol concentration, and OD stands for optical density. Numbers correspond to NaCl concentration. Data are the mean of triplicate bottles, and bars indicate ± the standard deviation.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490417&req=5

ijms-16-11834-f006: Biodegradation of phenol by Halomonas sp. strain 4-5 at different salt concentrations with 500 mg·L−1 phenol. The experiments were carried out in 125-mL serum bottles containing 50 mL of mineral salts medium (MSM) with 5% inoculation. PH stands for phenol concentration, and OD stands for optical density. Numbers correspond to NaCl concentration. Data are the mean of triplicate bottles, and bars indicate ± the standard deviation.
Mentions: The effects of salinity on the growth and phenol degradation of strain 4-5 was investigated in mineral salts medium (MSM) containing 500 mg·L−1 phenol and various concentration of NaCl (Figure 6). Halomonas sp. strain 4-5 showed optimal growth and phenol degradation at 5% NaCl. The strain was able to remove phenol after 68 h when cultivated in medium containing 500 mg·L−1 phenol and 3%, 5%, 8%, 10% and 12% NaCl. The removal rates were 96.2%, 99.8%, 98.9%, 94.7% and 86.3%, respectively. When the salinity increased to more than 12%, the phenol removal rate decreased significantly. A few studies have already reported successful phenol removal under salt conditions; most of these investigated the degradation ability in fixed salinity or with a narrow range of salinities. Peyton et al. [21] enriched five bacterial cultures from diverse saline environments capable of degrading phenol from 50 mg·L−1 to lower than 2 mg·L−1 at 10% (w/v) NaCl. Bonfá et al. [22] isolated three halophilic strains from different saline environments identified as Halomonas organivorans, Arhodomonas aquaeolei and Modicisalibacter tunisiensis that could grow in a medium with 10% salinity and 280 mg·L−1 phenol. Kobayashi et al. [23] separated three marine bacteria identified as Acinetobacter spp. EBR01, EBR02 and C. marina EBR04 from marine environments that could degrade 100 mg·L−1 phenol at 3.7% salinity. However, these studies only investigated phenol degradation under a fixed salinity. Gayathri and Vasudevan [24] examined the phenol degradation ability of a moderately halophilic bacterial consortium, which could degrade 50 mg·L−1 phenol with a removal rate of 95%, 99%, 93% and 89% when the NaCl concentration was 3%, 5%, 7% and 10%, respectively. By comparison, the salt tolerance range of the strain obtained in this study was up to 3%–12%. A detailed investigation of the effects of various salinities on growth and phenol degradation of the strain was reported. Additionally, the strain could degrade 500 mg·L−1 phenol over 94% at 3%–10% NaCl. Compared with previous reports, strain 4-5 obtained in this study had the advantage not only of a high removal rate, but also tolerance to a high salinity and initial concentration of phenol, which may contribute to phenol removal in the biological treatment of saline wastewater. Strain 4-5 was screened from the community E3, which was identified as having the best phenol-degrading capability among the 43 bacterial enrichments cultivated in the high-throughput screening system. The strain obtained from this high-throughput system had a unique phenol-degrading character compared to previous reported strains using the conventional screening techniques. The high-throughput system had the advantages not only of increasing the number of the screened samples, but also of improving the phenol-degrading ability of the gained strains.

Bottom Line: Bacterial enrichments were cultivated in 48 deep well microplates instead of shake flasks or tubes.Measurement of phenol concentrations was performed in 96-well microplates instead of using the conventional spectrophotometric method or high-performance liquid chromatography (HPLC).PCR detection of the functional genes suggested that the largest subunit of multicomponent phenol hydroxylase (LmPH) and catechol 1,2-dioxygenase (C12O) were active in the phenol degradation process.

View Article: PubMed Central - PubMed

Affiliation: State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China. lzy1009a@163.com.

ABSTRACT
A high-throughput screening system for moderately halophilic phenol-degrading bacteria from various habitats was developed to replace the conventional strain screening owing to its high efficiency. Bacterial enrichments were cultivated in 48 deep well microplates instead of shake flasks or tubes. Measurement of phenol concentrations was performed in 96-well microplates instead of using the conventional spectrophotometric method or high-performance liquid chromatography (HPLC). The high-throughput screening system was used to cultivate forty-three bacterial enrichments and gained a halophilic bacterial community E3 with the best phenol-degrading capability. Halomonas sp. strain 4-5 was isolated from the E3 community. Strain 4-5 was able to degrade more than 94% of the phenol (500 mg · L(-1) starting concentration) over a range of 3%-10% NaCl. Additionally, the strain accumulated the compatible solute, ectoine, with increasing salt concentrations. PCR detection of the functional genes suggested that the largest subunit of multicomponent phenol hydroxylase (LmPH) and catechol 1,2-dioxygenase (C12O) were active in the phenol degradation process.

No MeSH data available.


Related in: MedlinePlus