1. 2Shailesh Dave, 2Devyani Tipre
Isolation and Screening of Acid Red -119 Decolorizing Bacteria and Decolorization Study
1Shweta Agrawal,
2Shailesh Dave, 2Devyani Tipre
1Department of Biotechnology, Sanghvi Institute of Management and Science, Indore, M.P.
2Department of Microbiology & Biotechnology, School of Sciences, Gujarat University, Ahmedabad

2. Introduction to Dye
The name of ‘acid dyes’ refers to the dyeing process, which means these dyes are applied for dyeing nitrogen-containing fibers such as wool, silk and polyamides using from neutral to acidic solutions (pH 2-6). Most synthetic food colours falls in this category.
During the synthesis of dyes and dyeing process in industries, dyes that are lost to the industrial wastewater remain recalcitrant.
Several dyes are mutagenic and carcinogenic.

3. Materials and Methods
Sample: 35 different samples were collected from various sites of Indore city.

4. Materials and Methods
Soil sample
Day 1
Day 2
Day 3
Day 4
Sand + ++
+++
++++
Compost Soil 1
Municipal waste water 1
Garden Soil 1
Garden Soil 2 -
‘+’: low; ‘++’: good; ‘+++’ : Significant; ‘++++’: Complete decolorization
Screening- Initial enrichment was carried out in Nutrient broth tubes containing 50 ppm dye. 1 g of soil was added to 10ml of distilled water and supernatant was used as inoculum.Tubes showing decolorization were used for further screening.

5. Secondary screening study
The various colonies were identified and their colony characters were recorded.
11 Gram positive & 14 Gram negative strains.
The potential of the isolates to decolorize the dye was further tested by observing their zone of inhibition on Nutrient agar plates containing 50 ppm.

6. Tertiary screening study
Four strains were then selected for further study and their decolorization time was determined.
Isolate
Time taken for >99%decolorization
A-3 7h
A-C6
12 h
A-C12b
27h
A-C5b
32 h

7. Conclusion
Thirty five samples were screened for enrichment and isolation of acid red 119 decolourizing bacteria.
Except garden soil-2 all the soil enrichment samples showed luxuriant growth in presence of 50 ppm dye.
Total 25 isolates were isolated and screened for the study.
Secondary screening was carried out based on the zone of clearance on solid agar plate.
Out of 25 isolates, 12 isolates showed the zone of clearance and 6 isolates showed > 2.0 ratio.
The highest 94.7% of decolourisation was achieved with isolate A-C5b after 120 h of incubation followed by 5 isolates giving >80% decolourisation.
Finally 4 isolates viz. A-3, A-C6 , A-C5b, A-C12b were selected that required as low as 7 h to as high as 32 h of incubation to decolourize >99% of the 50 ppm dye.
Further optimization study is in progress to develop an efficient acid red 119 decolourizing/degrading bacterial strain.