Efficient biosorption of nanoplastics by food-derived lactic acid bacterium

Nanoplastics (NPs) are increasingly prevalent in ecosystems and human food chains and pose potential health risks, necessitating effective removal strategies applicable to both environmental and intestinal conditions. However, bacteria capable of functioning in both contexts remain poorly explored. Here, the food-derived bacterium Leuconostoc mesenteroides CBA3656 exhibited high NP biosorption efficiency across a wide range of NP concentrations (10-200 ppm), pH values (3-9), and temperatures (4-55°C), along with rapid adsorption at short contact times. Biosorption behavior followed pseudo-first-order kinetics and the Langmuir isotherm model, indicating predominantly physical adsorption. Fourier-transform infrared spectroscopy revealed that functional groups such as PO, CO, and COC in cell wall and membrane components contribute to NP interactions. Under simulated intestinal fluid, strain CBA3656 outperformed other Leuconostoc mesenteroides strains, and in vivo experiments demonstrated significantly enhanced fecal excretion of NPs. These results identify strain CBA3656 as a promising microbial biosorbent for NP mitigation.