Optimization of lead and cadmium biosorption by Lactobacillus acidophilus using response surface methodology

Despite the comprehensive effort to reduce exposure to heavy metals and protect human health, the release of toxic metals such as Pb2+ and Cd2+ into the environment has remained a critical problem yet. Hence, the present study was conducted to assay the potential of native species Lactobacillus acidophilus for biosorption of Pb2+ and Cd2+ considering the effect of pH (3-7), inoculum size (15-55 CFU/mL), and metal concentration (10-90 ppb). The experimental design and response surface methodology (RSM) were taken into account with the aim of acquiring the optimum condition for the independent variables. The results demonstrated the 87.68% removal of Pb2+ at the pH of 4 along with the increase of inoculum size providing more available binding sites. Conversely, the Cd2+ biosorption capacity was enhanced as a result of pH and inoculum size rising. As a brief, the maximum biosorption (>69%) was obtained at the optimum condition including the pH of 4, the metal concentration of 35 ppb, and inoculum size of 45 CFU/mL. The results represented the considerable potential of L. acidophilus as a promising approach for heavy metal removal.