Biosorption of cadmium by potential probiotic Pediococcus pentosaceus using in vitro digestion model

An exponential increase of heavy metal toxicant in the human body is a growing health-related problem. In the present study, Pediococcus pentosaceus FB145 and FB181 strains were isolated from fermented seafood and served as highly Cd-resistant strains. The unchanged structural cells of P. pentosaceus strains after treatment with Cd cations were investigated using a scanning electron microscope energy dispersive X-ray analysis. Furthermore, both P. pentosaceus strains showed strong human gastrointestinal tract resistance properties. The Cd biosorption results fit the pseudo-second-order kinetics with capacities for P. pentosaceus FB145 and FB181 for Cd were 52.8 and 50.3 mg/g, respectively, whereas the maximum biosorption capacities were 52.65 and 50.35 mg/g, respectively. The equilibrium data were well fitted to the Freundlich isotherm model. The binding of Cd to bacterial cells may be caused by the presence of different functional groups such as carboxyl, amide, and phosphate on cell surface, which was confirmed by the Fourier transform infrared-attenuated total reflectance spectra. Moreover, these strains decreased the Cd bioaccessibility by 44.7-46.8% in the in vitro digestion model. These findings indicate that P. pentosaceus FB145 and FB181 are novel potent biosorbent for preventing cadmium toxicity and reducing its absorption into the human body.