Effectual bio-decolourization of anthraquinone dye reactive blue-19 containing wastewater by Bacillus cohnii LAP217: process optimization

Abstract

The Colored wastewaters produced from textile industries are enriched with toxic reactive dyes that cause serious biotic risk and ecological disturbances. The present study aims to decolourize an anthraquinone reactive blue-19 dye from aqueous solution by Bacillus cohnii LAP217. The selection of influential process parameters and optimization of process condition is performed using two-point factorial analysis and response surface method, respectively. The results reveal that the decolourization of dye is positively influenced by supplementation of di-sodium hydrogen phosphate (coefficient estimate: 7.4). The bacterium has exhibited 87.3 ± 0.4% decolourization of initial dye concentration 50 mg/L during the model validation through confirmatory experiment analysis, which has satisfactory correlation with model predicted response. However, the initial chromate concentration >50 mg/L in the medium have negative influence on performance of system by reducing the dye decolourization response below <70%, under similar process condition. Colored bacterial mass is obtained after the centrifugation of treated dye solution and a significant change in the UV-visible absorption peak is observed between raw and treated dye solution, which confirms the bio-accumulation of reactive blue-19 dye. The bacteria could exhibit significant American dyes manufactures institutes (ADMI) value reduction percentage of 79.84% during treatment of real wastewater.