Limits...
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

Mortality of Daphnia magna exposed to 75 % dilution of the culture supernatants containing azo dyes treated with bacteria consortium under different incubation processes
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4553892&req=5

T4: Mortality of Daphnia magna exposed to 75 % dilution of the culture supernatants containing azo dyes treated with bacteria consortium under different incubation processes

Mentions: The results of the toxicity assay are presented as percent death of Daphnia magna occurred in the bacterial consortium treated azo dyes broth under different incubation processes. The toxicity data showed that degradation under microaerophilic and sequential aerobic/microaerophilic conditions were not sufficient to remove the complete toxicity of dyes as little (1 to 4 %) mortality of Daphnia magna was observed in these treatment samples (Table 4(Tab. 4)). In addition, the partially decolorized azo dyes samples under aerobic conditions showed near about same mortality as like control dyes viz. 39 % RB5, 35 % RO16, 37 % DR78 and 41 % DR 81. In contrast, the sequential microaerophilic/ aerobic process treated dyes sample doesn’t show any mortality suggesting the complete removal of toxicity from decolorized broths. Therefore, a last sequential aerobic stage is necessary to diminish the toxicity from dyes decolorized broths. It can be concluded that, even bacterial consortium was able to completely decolorize all the dyes under microaerophilic, sequential aerobic/microaerophilic and sequential microaerophilic/aerobic processes, the final aerobic stage is necessary for aromatic amines removal (Sponza and Isik, 2005[53]).


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)

Mortality of Daphnia magna exposed to 75 % dilution of the culture supernatants containing azo dyes treated with bacteria consortium under different incubation processes
© Copyright Policy - open-access
Related In: Results  -  Collection

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

T4: Mortality of Daphnia magna exposed to 75 % dilution of the culture supernatants containing azo dyes treated with bacteria consortium under different incubation processes
Mentions: The results of the toxicity assay are presented as percent death of Daphnia magna occurred in the bacterial consortium treated azo dyes broth under different incubation processes. The toxicity data showed that degradation under microaerophilic and sequential aerobic/microaerophilic conditions were not sufficient to remove the complete toxicity of dyes as little (1 to 4 %) mortality of Daphnia magna was observed in these treatment samples (Table 4(Tab. 4)). In addition, the partially decolorized azo dyes samples under aerobic conditions showed near about same mortality as like control dyes viz. 39 % RB5, 35 % RO16, 37 % DR78 and 41 % DR 81. In contrast, the sequential microaerophilic/ aerobic process treated dyes sample doesn’t show any mortality suggesting the complete removal of toxicity from decolorized broths. Therefore, a last sequential aerobic stage is necessary to diminish the toxicity from dyes decolorized broths. It can be concluded that, even bacterial consortium was able to completely decolorize all the dyes under microaerophilic, sequential aerobic/microaerophilic and sequential microaerophilic/aerobic processes, the final aerobic stage is necessary for aromatic amines removal (Sponza and Isik, 2005[53]).

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