1. Isolation & Characterization of an unknown bacterium from an industrial waste water and study of its azo dye decolourisation and degradation capability
Puspita Bhattacharya, Dr.Papita Das*
INTRODUCTION
RESULTS
Azo dyes are Chemically & photolytically stable, highly persistent in natural environment causes ecotoxic hazards, highly mutagenic, carcinogenic, introduces potential danger of bioaccumulation in human body
Congo red is the sodium salt of 3,3'-([1,1'-biphenyl]-4,4'-diyl)bis(4-aminonaphthalene-1-sulfonic acid), formula: C32H22N6Na2O6S2; molecular weight is g/mol)
The waste water sample was collected from a waste disposal site of a textile processing and dying industry near Rajarhat (Kolkata, West Bengal, India)
The decolorization experiment was done by inoculating loopful of bacterium into 100 ml of MSM in 250 ml conical flask at at 30o c and 130 rpm
Effect of various dye concentrations
The effect of different concentrations of congo red on decolorization was observed by taking mg/l respectively, the required time was 4 hr, 8 hr, 24 hr, 30 hr.
Increasing concentration of Congo red repress the percentage of decolorization. The dye decolorization rate was decreased after 500 ppm
Effect of various pH
pH of the medium was varied from 3-9 and as the pH increases from 7 the % of decolorization gradually decreases with further decrease in pH
At pH 3, the removal of the dye was maximum and at pH 9, the removal of the congo red dye minimum
Effect of inoculum concentration
Inoculum % was varied from 5-20% and the required time for the removal was 6 hr,18 hr,21 hr,24 hr and 32 hr and % of removal of congo red was decreased with increase in inoculum percentage
% of dye removal of congo red dye with increase in pH at a concentration of 70 mg/l
AIM
Percentage of the dye removal with increase in inoculum concentration
This study presents biological decolourization of congo red through a microbial isolate obtained from dye contaminated textile effluent
To obtain the maximum operating condition for the dye removal by changing the parameters i.e. Concentration range, pH and the inoculum percentage for the bacterium
METHODS
Isolation and screening of the bacterium
Serially diluted soil sample was plated on nutrient agar plate supplemented with 50 mg/l congo red dye, bacterium capable of growing on the plates were isolated and the bacterium was further screened in the mineral salt medium( MSM) agar plate supplemented with 1% glucose and 0.5g/l yeast extract for confirmation of its dye degrading capability and to obtain pure culture
Composition of the mineral salt medium (MSM):
1.CaCl2, 2H
2.KH2PO4- 0.1
3.NaCl- 0.8
4.NH4Cl- 1.0
5.MgSO4,7H2O- 0.2
6.KCl- 0.1
7.CoCl2,6H2O- 0.1mg/l
8.MnCl2,4H2O mg/l
9.ZnCl mg/l
10.CuSO4,5H2O mg/l
11.NiCl2,6H mg/l
12.Na2MoO mg/l
13.Na2SeO4-0.01mg/l
14. Agar- 30g/l
CONCLUSION
The isolated microorganism has a potential for the removal of congo red dye at a higher concentration and the bacterium works well in the acidic pH and as the pH increases, the percentage of removal decreased. The percentage of removal also decreased with increasing in the concentration of the dye .
REFERENCE
Banat, I.M., Nigam, P., Singh, D. & Marchant, R Microbial
decolorization of textile dye containing effluents: a review.
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Bras, R., Ferra, I.A., Pinheiro, H.M. & Goncalves, I.C Batch
tests for assessing decolorization of azo dyes by methanogenic and
mixed cultures. Journal of Biotechnology 89, 155–162
Characterization of aerobic azo dye degrading bacteria and their
activity in biofilms. Water Science and Technology 36, 215–220.
Percentage of decolourization of congo red at various dye concentration.