PPTCC 1015S Strain of Bacillus cereus as an Effective Medium for Removing Azo Dyes; Acid Blue 113 and Acid Orange 7

Abstract

Background: Bio-remediation methods of organic pollutants are promising due to their high efficiency, low cost, and green chemistry. These methods are effective alternatives to traditional elimination methods. Methods: Bacillus cereus PTCC 1015S strain was used to eliminate acid blue 113 (AB113) and acid orange 7 (AO7) from aqueous solutions. The bacteria were activated in the Luria Bertani Broth (MILLER) culture medium. The effective parameters such as incubation time and temperature, pH of dye solution, dye concentration, and the bacterial inoculation quantity on decolorization were investigated. Kinetic and thermodynamic studies were done to clarify the different aspects of the introduced method. Also, the reliability of the method to remove studied dyes was investigated in dye factory wastewater samples. Results: The first-order kinetic model was the best model to describe the kinetics of decolorization. The obtained thermodynamic data showed that the elimination process was endothermic (∆H0=+29.03, 30.53) while it was spontaneous (∆G0<0) for both studied dyes and so entropy change (∆S0=+109.63, 116.32) was an effective force in the decolorization. Under optimized conditions, B. cereus PTCC 1015S showed high average removal; 98.5 and 99.3 % for AB113 and AO7 respectively in dye model solutions. The removal efficiency was more than 85 % for both studied dyes in wastewater spiked samples. Conclusions: The B. cereus PTCC 1015 strain was capable of being exploited in the removal of AB113 and AO7 dye molecules as an affordable and eco-amiable method for the treatment of aqueous samples contaminated with the studied azo dyes.