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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

Decolorization of four azo dyes (100 mg L-1) by individual P. rettgeri strain HSL1 (-■-), Pseudomonas sp. SUK1 (-▲-) and its consortium (-x-) under microaerophilic conditions. The percent decolorization was measured at respective dyes λmax after different time of intervals at 30 ± 0.2 °C incubation temperature. Data points indicate the mean of three independent replicates, standard error of mean is indicated by error bars.
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Figure 1: Decolorization of four azo dyes (100 mg L-1) by individual P. rettgeri strain HSL1 (-■-), Pseudomonas sp. SUK1 (-▲-) and its consortium (-x-) under microaerophilic conditions. The percent decolorization was measured at respective dyes λmax after different time of intervals at 30 ± 0.2 °C incubation temperature. Data points indicate the mean of three independent replicates, standard error of mean is indicated by error bars.

Mentions: The chemical structural differences in textile dyes due to the substitution of various functional groups on aromatic base greatly influence their decolorization rates (Chivukula and Renganathan, 1995[10]; Pasti-Grigsby et al., 1992[40]). Thus, the bacterial consortium consisting of previously isolated dyes degrading bacteria P. rettgeri strain HSL1 and Pseudomonas sp. SUK1 has been developed and investigated for decolorization of structurally different azo dyes under microaerophilic and aerobic conditions. The results of the decolorization study indicate that both the individual cultures and its consortium were failed to completely decolorize selected dyes (100 mg L-1) under aerobic conditions and only 12-22 % performance was achieved within 48 h. On the other hand, individual cultures P. rettgeri strain HSL1 and Pseudomonas sp. SUK1 were able to completely decolorize two azo dyes viz. RO 16 (24 and 18 h) and DR 78 (36 and 42 h) and partially decolorize another dyes viz. RB 5 (52 and 58 %) and DR 81 (85 and 92 %) in microaerophilic conditions within 48 h respectively (Figure 1(Fig. 1)).


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)

Decolorization of four azo dyes (100 mg L-1) by individual P. rettgeri strain HSL1 (-■-), Pseudomonas sp. SUK1 (-▲-) and its consortium (-x-) under microaerophilic conditions. The percent decolorization was measured at respective dyes λmax after different time of intervals at 30 ± 0.2 °C incubation temperature. 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 1: Decolorization of four azo dyes (100 mg L-1) by individual P. rettgeri strain HSL1 (-■-), Pseudomonas sp. SUK1 (-▲-) and its consortium (-x-) under microaerophilic conditions. The percent decolorization was measured at respective dyes λmax after different time of intervals at 30 ± 0.2 °C incubation temperature. Data points indicate the mean of three independent replicates, standard error of mean is indicated by error bars.
Mentions: The chemical structural differences in textile dyes due to the substitution of various functional groups on aromatic base greatly influence their decolorization rates (Chivukula and Renganathan, 1995[10]; Pasti-Grigsby et al., 1992[40]). Thus, the bacterial consortium consisting of previously isolated dyes degrading bacteria P. rettgeri strain HSL1 and Pseudomonas sp. SUK1 has been developed and investigated for decolorization of structurally different azo dyes under microaerophilic and aerobic conditions. The results of the decolorization study indicate that both the individual cultures and its consortium were failed to completely decolorize selected dyes (100 mg L-1) under aerobic conditions and only 12-22 % performance was achieved within 48 h. On the other hand, individual cultures P. rettgeri strain HSL1 and Pseudomonas sp. SUK1 were able to completely decolorize two azo dyes viz. RO 16 (24 and 18 h) and DR 78 (36 and 42 h) and partially decolorize another dyes viz. RB 5 (52 and 58 %) and DR 81 (85 and 92 %) in microaerophilic conditions within 48 h respectively (Figure 1(Fig. 1)).

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