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Biodegradation and detoxification of textile azo dyes by bacterial consortium under sequential microaerophilic/aerobic processes.

Lade H, Kadam A, Paul D, Govindwar S - EXCLI J (2015)

Bottom Line: RB 5 (0.08 mM), RO 16 (0.06 mM), DR 78 (0.07 mM) and DR 81 (0.09 mM) resulted into the formation of aromatic amines.Additionally, 62-72 % reduction in total organic carbon content was observed in all the dyes decolorized broths under sequential microaerophilic/aerobic processes suggesting the efficacy of method in mineralization of dyes.Notable induction within the levels of azoreductase and NADH-DCIP reductase (97 and 229 % for RB 5, 55 and 160 % for RO 16, 63 and 196 % for DR 78, 108 and 258 % for DR 81) observed under sequential microaerophilic/aerobic processes suggested their critical involvements in the initial breakdown of azo bonds, whereas, a slight increase in the levels of laccase and veratryl alcohol oxidase confirmed subsequent oxidation of formed amines.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Engineering, Konkuk University, Seoul-143-701, Korea.

ABSTRACT
Release of textile azo dyes to the environment is an issue of health concern while the use of microorganisms has proved to be the best option for remediation. Thus, in the present study, a bacterial consortium consisting of Providencia rettgeri strain HSL1 and Pseudomonas sp. SUK1 has been investigated for degradation and detoxification of structurally different azo dyes. The consortium showed 98-99 % decolorization of all the selected azo dyes viz. Reactive Black 5 (RB 5), Reactive Orange 16 (RO 16), Disperse Red 78 (DR 78) and Direct Red 81 (DR 81) within 12 to 30 h at 100 mg L(-1) concentration at 30 ± 0.2 °C under microaerophilic, sequential aerobic/microaerophilic and microaerophilic/aerobic processes. However, decolorization under microaerophilic conditions viz. RB 5 (0.26 mM), RO 16 (0.18 mM), DR 78 (0.20 mM) and DR 81 (0.23 mM) and sequential aerobic/microaerophilic processes viz. RB 5 (0.08 mM), RO 16 (0.06 mM), DR 78 (0.07 mM) and DR 81 (0.09 mM) resulted into the formation of aromatic amines. In distinction, sequential microaerophilic/ aerobic process doesn't show the formation of amines. Additionally, 62-72 % reduction in total organic carbon content was observed in all the dyes decolorized broths under sequential microaerophilic/aerobic processes suggesting the efficacy of method in mineralization of dyes. Notable induction within the levels of azoreductase and NADH-DCIP reductase (97 and 229 % for RB 5, 55 and 160 % for RO 16, 63 and 196 % for DR 78, 108 and 258 % for DR 81) observed under sequential microaerophilic/aerobic processes suggested their critical involvements in the initial breakdown of azo bonds, whereas, a slight increase in the levels of laccase and veratryl alcohol oxidase confirmed subsequent oxidation of formed amines. Also, the acute toxicity assay with Daphnia magna revealed the nontoxic nature of the dye-degraded metabolites under sequential microaerophilic/aerobic processes. As biodegradation under sequential microaerophilic/aerobic process completely detoxified all the selected textile azo dyes, further efforts should be made to implement such methods for large scale dye wastewater treatment technologies.

No MeSH data available.


Related in: MedlinePlus

Effect of [a] Microaerophilic and shaking incubation, [b] incubation temperature, [c] initial broth pH and [d] dyes concentration on decolorization of azo dyes by bacterial consortium. Decolorization was measured after 30 h for RB5, 12 h for RO 16, 18 h for DR 78 and 24 h for DR 81. Data points indicate the mean of three independent replicates, standard error of mean is indicated by error bars.
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Figure 2: Effect of [a] Microaerophilic and shaking incubation, [b] incubation temperature, [c] initial broth pH and [d] dyes concentration on decolorization of azo dyes by bacterial consortium. Decolorization was measured after 30 h for RB5, 12 h for RO 16, 18 h for DR 78 and 24 h for DR 81. Data points indicate the mean of three independent replicates, standard error of mean is indicated by error bars.

Mentions: Decolorization performance of bacteria has been known to be greatly influenced by various environmental conditions. For the enhancement of decolorization rate and to design an affordable treatment technology for textile effluent containing structurally different azo dyes, the optimization of decolorization conditions has been carried out. The complete and enhanced decolorization of all azo dyes (100 mg L-1) was observed within 12-30 h by bacterial consortium under microaerophilic conditions while only 12 % RB 5, 20 % RO 16, 22 % DR 78, and 21 % DR 81 dye removal performance was achieved under shaking conditions within the same time (Figure 2a(Fig. 2)). Hence, the microaerophilic conditions were adopted to optimize pH, temperature and dye concentration for enhanced degradation studies.


Biodegradation and detoxification of textile azo dyes by bacterial consortium under sequential microaerophilic/aerobic processes.

Lade H, Kadam A, Paul D, Govindwar S - EXCLI J (2015)

Effect of [a] Microaerophilic and shaking incubation, [b] incubation temperature, [c] initial broth pH and [d] dyes concentration on decolorization of azo dyes by bacterial consortium. Decolorization was measured after 30 h for RB5, 12 h for RO 16, 18 h for DR 78 and 24 h for DR 81. Data points indicate the mean of three independent replicates, standard error of mean is indicated by error bars.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4553892&req=5

Figure 2: Effect of [a] Microaerophilic and shaking incubation, [b] incubation temperature, [c] initial broth pH and [d] dyes concentration on decolorization of azo dyes by bacterial consortium. Decolorization was measured after 30 h for RB5, 12 h for RO 16, 18 h for DR 78 and 24 h for DR 81. Data points indicate the mean of three independent replicates, standard error of mean is indicated by error bars.
Mentions: Decolorization performance of bacteria has been known to be greatly influenced by various environmental conditions. For the enhancement of decolorization rate and to design an affordable treatment technology for textile effluent containing structurally different azo dyes, the optimization of decolorization conditions has been carried out. The complete and enhanced decolorization of all azo dyes (100 mg L-1) was observed within 12-30 h by bacterial consortium under microaerophilic conditions while only 12 % RB 5, 20 % RO 16, 22 % DR 78, and 21 % DR 81 dye removal performance was achieved under shaking conditions within the same time (Figure 2a(Fig. 2)). Hence, the microaerophilic conditions were adopted to optimize pH, temperature and dye concentration for enhanced degradation studies.

Bottom Line: RB 5 (0.08 mM), RO 16 (0.06 mM), DR 78 (0.07 mM) and DR 81 (0.09 mM) resulted into the formation of aromatic amines.Additionally, 62-72 % reduction in total organic carbon content was observed in all the dyes decolorized broths under sequential microaerophilic/aerobic processes suggesting the efficacy of method in mineralization of dyes.Notable induction within the levels of azoreductase and NADH-DCIP reductase (97 and 229 % for RB 5, 55 and 160 % for RO 16, 63 and 196 % for DR 78, 108 and 258 % for DR 81) observed under sequential microaerophilic/aerobic processes suggested their critical involvements in the initial breakdown of azo bonds, whereas, a slight increase in the levels of laccase and veratryl alcohol oxidase confirmed subsequent oxidation of formed amines.

View Article: PubMed Central - PubMed

Affiliation: Department of Environmental Engineering, Konkuk University, Seoul-143-701, Korea.

ABSTRACT
Release of textile azo dyes to the environment is an issue of health concern while the use of microorganisms has proved to be the best option for remediation. Thus, in the present study, a bacterial consortium consisting of Providencia rettgeri strain HSL1 and Pseudomonas sp. SUK1 has been investigated for degradation and detoxification of structurally different azo dyes. The consortium showed 98-99 % decolorization of all the selected azo dyes viz. Reactive Black 5 (RB 5), Reactive Orange 16 (RO 16), Disperse Red 78 (DR 78) and Direct Red 81 (DR 81) within 12 to 30 h at 100 mg L(-1) concentration at 30 ± 0.2 °C under microaerophilic, sequential aerobic/microaerophilic and microaerophilic/aerobic processes. However, decolorization under microaerophilic conditions viz. RB 5 (0.26 mM), RO 16 (0.18 mM), DR 78 (0.20 mM) and DR 81 (0.23 mM) and sequential aerobic/microaerophilic processes viz. RB 5 (0.08 mM), RO 16 (0.06 mM), DR 78 (0.07 mM) and DR 81 (0.09 mM) resulted into the formation of aromatic amines. In distinction, sequential microaerophilic/ aerobic process doesn't show the formation of amines. Additionally, 62-72 % reduction in total organic carbon content was observed in all the dyes decolorized broths under sequential microaerophilic/aerobic processes suggesting the efficacy of method in mineralization of dyes. Notable induction within the levels of azoreductase and NADH-DCIP reductase (97 and 229 % for RB 5, 55 and 160 % for RO 16, 63 and 196 % for DR 78, 108 and 258 % for DR 81) observed under sequential microaerophilic/aerobic processes suggested their critical involvements in the initial breakdown of azo bonds, whereas, a slight increase in the levels of laccase and veratryl alcohol oxidase confirmed subsequent oxidation of formed amines. Also, the acute toxicity assay with Daphnia magna revealed the nontoxic nature of the dye-degraded metabolites under sequential microaerophilic/aerobic processes. As biodegradation under sequential microaerophilic/aerobic process completely detoxified all the selected textile azo dyes, further efforts should be made to implement such methods for large scale dye wastewater treatment technologies.

No MeSH data available.


Related in: MedlinePlus