EFFECT OF MULTIPLE FACTORS ON AZO DYE DECOLORIZATION USING A MODERATE HALOPHILIC BACTERIUM EXIGUOBACTERIUM AURANTIACUM (ESL52)R. PALANIVELAN, A. SAKTHI THESAI, S. RAMYA AND P.M. AYYASAMY
Halo-tolerant dye decolorizing bacteria ESL52 was isolated from a textile sludge contaminated with dye and the strain was identified as Exiguobacterium aurantiacum using 16S rRNA sequencing method. This strain showed 96.78 % decolorization efficiency within 48 hours in LB broth. The significant factors that influence dye decolorization process were obtained using Plackett-Burman design: starch, yeast extract and pH. These factors were optimized using central composite design, which was followed by response surface methodology (RSM). The dye removal rate was found to vary from 5.06 to 88.30%. The established optimal concentration of the variables was found to be as follows: starch - 0.49% (w/v); yeast extract - 0.60% (w/v); and pH - 7.10. This optimal condition yielded 88.26% of decolorization under experimental setup, which was in agreement with the predicted value of 89.73%. This study confirmed that the specific interactions of co-substrates with pH would be a key factor for effective decolorization of remazol golden yellow dye under halophilic culture condition.