Bacterial degradation of textile dyes under saline condition

Presented by: Farzana Kausar

IntroductionDyes•A dye is a colored substance that has an affinity to the substrate to which it is being applied. •Amongst the synthetic dyes, azo dyes are the largest group.

Uses

These dyes are widely used in textile, food, cosmetics, pharmaceuticals and paper industry.

Problems cussed by dyes

Chemical nature Pollution Disturb aquatic life Carcinogenic, mutagenic

Biodegradation of textile dyes

Microorganisms Enzymes systemSteps involved in degradationAdvantages

Effects of salt on microbial degradtion

Various salts are used in dyeing industrySalt concentration up to 15-20% High salt concentarion cause plasmolysis Halotolerant micoorganisms

Objective of the study

This study was planned with the following objectives:• Isolation of salt tolerating bacteria from dye contaminated wastewater, sludge and soil.• Evaluate performance of bacteria for the removal of different azo dyes under saline conditions.

MATERIALS AND METHODS Dyes

Reactive Black-5,

Reactive Blue BRS and

Reactive Golden Ovifix

Culture Medium

MSM

pH-7.2

ISOLATION OF AZO DYE DECOLORIZING BACTERIA

1. Sampling Karachi Faisalabad Khewra

2. Isolation Procedure

3. Purification of Bacterial Culture

Table 1: Isolation of salt tolerant bacterial strains Karachi Faisalabad Khewra

Ocean

water Ocean sludge

Noshad textile mill

Qazaffi textile mill

Saline soil of khewra

salt mines KW-1

KW-2

KW-3

KW-4

KW-5

KW-6

KW-7

KW-8

KW-9

KW-10

KW-11

KW-12

KW-13

KW-14

KW-15

KW-16

KW-17

KW-18

KS-1 KS1-19

KS-2 KS-20

KS-3 KS-21

KS-4 KS-22

KS-5 KS-23

KS-6 KS-24

KS-7 KS-25

KS-8 KS-26

KS-9 KS-27

KS-10 KS-28

KS-11 KS-29

KS-12 KS30

KS-13

KS-14

KS-15

KS-16

KS-17

KS-18

F-1 F-19

F-2 F-20

F-3

F-4

F-5

F-6

F-7

F-8

F-9

F-10

F-11

F-12

F-13

F-14

F-15

F-16

F-17

F-18

T-1 T-19

T-2 T-20

T-3 T-21

T-4 T-22

T-5 T-23

T-6 T-24

T-7

T-8

T-9

T-10

T-11

T-12

T-13

T-14

T-15

T-16

T-17

T-18

S-1

S-2

S-3

S-4

S-5

S-6

S-7

S-8

S-9

S-10

SCREENING EFFICIENT BACTERIAL STRAINS FOR DECOLORIZATION OF

AZO DYES •On the basis of better decolorization efficiency initially 16 isolates were selected after 24 hours of decolorization results.

•Three most efficient strains were used for further experiment.

DECOLORIZATION OF AZO DYES UNDER SALINE CONDITIONS

KS-26, KS-23 and T-14 salinity levels ranging from 0-100 g l-1 of NaCl. The medium to inoculum ratio was 20:1. Decolorization of azo dyes

RESULTS

Isolation of salt tolerated bacterial strains

The selected strains of bacteria capable of degrading azo dye at 50 g NaCl l-1

Table 2: The selected strains of bacteria capable of degrading azo dye at 50 g NaCl l-

Bacterial Strains % Decolorization

KS-23 100

KS-26 100

T-14 100

T-17 90

F-9 70

S-4 80

DEGRADATION OF REACTIVE BLACK-5

All the three strains of bacteria were able to decolorize Reactive Black-5 up to salt concentration of 60 g NaCl l-1. The degradation rate was affected with increase in salt concentration

0

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120

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Time (h)

Deco

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Fig. 1: Potential of bacterial strain KS-23 for decolorization of Reactive Black-5 at different salt concentration (0-60 g NaCl l-1)

0

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60

80

100

120

0 4 8 12 16 20 24

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Fig. 2: Potential of bacterial strain KS-26 for decolorization of Reactive Black-5 at different salt concentration (0-60 g NaCl l-1)

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100

120

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Fig. 3: Potential of bacterial strain T-14 for decolorization of Reactive Black-5 at different salt concentration (0-60 g NaCl l -1)

DEGRADATION OF REACTIVE BLUE BRS

All the selected strains were able to degrade Reactive Blue BRS efficiently. Bacterial strains were able to tolerate salt concentration up to 100 g NaCl l-1.

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100

120

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Deco

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70 80 90 100

Fig. 4: Potential of bacterial strain KS-23 for decolorization Reactive Blue BRS at different salt concentration (0-100 g NaCl l-1)

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40

60

80

100

120

0 4 8 12 16 20 24

Time (h)

Deco

lori

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0 10 20 30 40 50 60 70

80 90 100

Fig. 5: Potential of bacterial strain KS-26 for decolorization Reactive Blue BRS at different salt concentration (0-100 g NaCl l-1)

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60

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100

120

0 4 8 12 16 20 24

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70 80 90 100

Fig. 6: Potential of bacterial strain T-14 for decolorization Reactive Blue BRS at different salt concentration (0-100 g NaCl l-1)

DEGRADATION OF REACTIVE GOLDEN OVIFIX

Bacterial strains were able to decolorize Reactive Golden Ovifix. All the three strains were able to decolorize Reactive Golden Ovifix in the presence of salt concentration 0-60 g NaCl l-1.

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0 4 8 12 16 20 24

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Fig. 7: Potential of bacterial strain KS-23 for decolorization Reactive Golden Ovifix at different salt concentration (0-100 g NaCl l-1)

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100

120

0 4 8 12 16 20 24

Time (h)

Deco

loriz

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)0 10 20 30 40 50 60

Fig. 8: Potential of bacterial strain KS-26 for decolorization Reactive Golden Ovifix at different salt concentration (0-100 g NaCl l-1)

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100

120

0 4 8 12 16 20 24

Time (h)

Deco

lori

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)0 10 20 30 40 50 60

Fig. 9: Potential of bacterial strain T-14 for decolorization Reactive Golden Ovifix at different salt concentration (0-100 g NaCl l-1)

CONCLUSION

This research suggested that under high saline conditions microbial activity is affected but there are many bacteria that have natural ability to tolerate such saline conditions. Therefore use of such halotolerant bacteria can be useful for the degradation of azo dyes under saline conditions.