International Journal of Current Microbiology and Applied Sciences

ISSN: 2319-7706 Volume 2 Number 10 (2013) pp. 496-505

Biodegradation of textile azo dyes and its bioremediation potential using seed germination efficiency

C.Initha Lebanon Ebency1 *, S.Rajan2 , A.G.Murugesan3 , R.Rajesh4 , B.Elayarajah5

1Department of Microbiology, Sree Narayana Guru College, K.G. Chavadi, Coimbatore - 641105 2Department of Microbiology, M.R. College of Arts and Science, Manargudi, Tamilnadu, India 3Sri Paramakalyani Centre for Environmental Sciences, Manonmaniam Sundarnar University, Tirunelveli, Tamilnadu, India 4RndBio, The Biosolution Company, Coimbatore, India 5School of Biological Sciences, CMS College of Science and Commerce, Coimbatore-641049, India

ABSTRACT

To decolourize indigo blue dye which was used mostly in all jean manufacturing textile industries using the soil and sludge isolate, Bacillus spp. Soil and sludge from textile effluent discharge sites were collected from different jeans manufacturing industries in Coimbatore district. Indigo blue dye degrading organisms were screened using a Zhou and Zimmermann (ZZ) screening media after serially diluted the collected samples. After screening and isolating the best dye decolourizer from the samples, optimization of dye degrading conditions were carried out. Different factors like temperature, pH, carbon source, nitrogen source, metallic salts, inoculum size and time course of decolourization was selected as optimization parameters. Phytotoxicity of dye and degraded dye was evaluated by measuring the relative changes in seed germination of three different plants Green gram (Vigna radiate), Kidney beans (Phaseolus vulgaris), Fenugreek (Trigonella foerum). Seven bacterial isolates were screened based on their ability to decolourize the indigo blue dyes from the soil and sludge samples. Dye decolourizer (DD4) decolourized upto 98% followed by DD2 with 81%. Both the isolates were identified as Bacillus sp1 and 2 after microscopic and biochemical characteristics. From the optimization analysis, the suitable optimized condition for the isolate, Bacillus sp2 was identified as sucrose (1%), ammonium chloride (0.25%), temperature (45 0C), pH (8.0), potassium dihydrogen-ortho- phosphate and inoculum dose (2%). Phytotoxicity of dye and degraded dye was evaluated after 6 days of study. No phytotoxicity was observed for the concentration of dye used in the study. Good germination and shoot, root length of the plants were observed for both dye and degraded dye exposed seeds after comparing with the control. The isolate from the effluent discharge site showed a potential of degrading dyes at faster rate with an application of good seed germinating efficiency. These properties thus found useful for the bioremediation of various textile industrial effluents, saving the ecosystem from harmful effects of various dyes.

Keywords

Indigo blue dye; Bacillus spp ; Different factors; Green gram (Vigna radiate); Kidney beans (Phaseolus vulgaris),; Fenugreek (Trigonella foerum).