Development of MOF exoskeleton with robust cytoprotection on bacterial cells enables enhanced bioremediation of pesticide pollution in soil.

In recent years, microorganisms such as bacteria have emerged as promising agents for bioremediation of pesticide-contaminated soil due to their high safety, sustainability, and less vulnerability. In this study, a durable and robust exoskeleton was developed in situ on bacterial cell surface through a facile one-pot biomimetic mineralization process using the porous zeolitic imidazolate frameworks-8 (ZIF-8) under amiable conditions. The ZIF-8 nanocoating endowed bacterial cells with significant resistance against various environmental stressors, including high temperature, pH, UV exposure, and osmotic pressure. Meanwhile, the porous ZIF-8 shell allowed the diffusion of small molecular nutrients for cell survival while protecting the coated cells from cytotoxic lysozyme attack. The introduction of the exogenous enzyme into the ZIF-8 coating, rather than genetically modified cells, significantly prolonged cell survival (79 % viability after 7 d) by generating the essential nutrients required by the coated cells in the nutrient-deficient environment. When returned to growth conditions, the normal proliferation potential of the released cells was reverted from the dormant state following the removal of the ZIF-8 exoskeleton, enabling more cells to survive in extreme oligotrophic environments. Furthermore, the ZIF-8 coated cells significantly enhanced cell adaptability and degradation efficiency in black soil and red clay compared to native inoculants, especially in unsterilized soil (100 mg kg within 5 d in black soil and 100 mg kg within 12 d in red clay). Overall, the experimental results demonstrate that the developed bioactive ZIF-8 coating has the potential to safeguard vulnerable microorganisms during efficient bioremediation of pesticide-polluted soil.