Optimization of cadmium and lead biosorption onto marine Vibrio alginolyticus PBR1 employing a Box-Behnken design

Abstract

Microorganisms are well capable of removing heavy metals by different mechanisms especially where the process of biosorption has attracted researchers in the recent years. Various bacteria and fungi are currently being used for biosorption of heavy metals, however, reports suggesting the use of bioluminescent Vibrio sp. for metal biosorption are rare. In this study, the dead biomass of Vibrio alginolyticus PBR1 was employed to remove two metals, cadmium (Cd) and lead (Pb) from a single aqueous system. The Box-Behnken design (BBD), a Response Surface Method (RSM), was used to optimize biosorption of metals by V. alginolyticus PBR1. The three major factors; pH, biosorbent dosage and metal concentration were optimized to remove the metals efficiently. The optimum conditions for V. alginolyticus PBR1 were pH 5.7, biosorbent dosage of 2.0 g L−1 and metal concentration of 50 mg L−1 for each metal showed to have removal efficiencies of 59.78 % and 82.20 % for Cd and Pb, respectively. Furthermore, the possible interactions between functional groups present on cell surface and metals were studied using Fourier Transform Infrared (FTIR) spectroscopy. The study provides potential application of bioluminescent Vibrio sp. for removing two metals simultaneously from heavy metal contaminated aqueous solution.