Biosorption of Cd2+ and Pb2+ from apple juice by the magnetic nanoparticles functionalized lactic acid bacteria cells

The pollution of heavy metals in fruit juice is still increasing and becoming a significant food safety issue worldwide nowadays. In this work, twelve strains of lactic acid bacteria (LAB) were evaluated for the biomass and their capability to adsorb Cd2+ and Pb2+. One strain of LAB capable of efficiently adsorbing heavy metals in apple juice was screened. The obtained LAB was functionalized by magnetic Fe3O4 nanoparticles (MNPs) and modified by Ethylenediaminetetraacetic acid dianhydride (EDTAD) for generation EDTAD-MNPs-LAB (EMB) adsorbent, which was further characterized by Scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results indicated that the strain of LAB was successfully functionalized and modified by MNPs and EDTAD. The maximum adsorption capacity of EMB adsorbent for Cd2+ and Pb2+ in apple juice was 0.57 mg/g and 0.17 mg/g, respectively. The EMB adsorbent could be rapidly separated from the sample solution with the help of magnetic field and the adsorption process has no significant impact on the quality of fruit juice. The regeneration experiments revealed that the EMB adsorbent could be successfully reused. The research provides a new insight and strategy for the effective adsorption and removal of heavy metals from juice.