A comprehensive study on the behavior of a novel bacterial strain Acinetobacter guillouiae for bioremediation of divalent copper

Abstract

Biological methods have been successfully used to mitigate heavy metal pollution problem in wastewater. The present study was aimed towards isolation of a novel indigenous bacterial strain, Acinetobacter guillouiae from activated sludge and its subsequent application in remediation of copper (Cu(2+)) from aqueous solution. Kinetic study of bioremediation was performed for initial Cu(2+) concentrations ranging from 40 to 150mgL(-1). Optimum values of nutrient dosage, pH, macronutrients [Nitrogen (N)-Phosphorus (P)-Potassium (K)] dosage, aerobic and facultative anaerobic conditions, temperature, and inoculum volume were determined by conducting separate batch bioremediation studies at 80mgL(-1) initial concentration of Cu(2+). Kinetic study showed that A. guillouiae removed 98.7% Cu(2+) for 80mgL(-1) initial concentration of Cu(2+) after 16h at an optimum solution pH of 7.0. Results also revealed that A. guillouiae showed maximum growth at double the standard composition of N, P and standard composition of K in nutrient dosage. Experimental data obtained in present study were utilized to validate different growth kinetic models such as Monod, Powell, Haldane, Luong, and Edwards. Growth kinetics of A. guillouiae was better understood by Luong model (R (2)=0.97). Higher values of coefficient of determination (R (2)=0.97-0.99) confirmed the suitability of the three-half-order kinetic model for representing the Cu(2+) bioremediation. A. guillouiae showed a robust removal mechanism for the bioremediation of Cu(2+).