Probiotic detoxification of heavy metals: functional assessment in simulated intestinal and ex vivo models

Introduction Bioremediation is an emerging, sustainable strategy that relies on microbial processes to detoxify environmental pollutants. Among these pollutants, heavy metals (HMs) are pervasive, non-degradable toxic elements that pose serious risks to human health. In this study, we individually evaluated three probiotic lactobacilli strains-Lactiplantibacillus plantarum LP14, Lactobacillus crispatus LCR04, and Lactobacillus acidophilus LA12-for their capacity to detoxify cadmium, chromium, mercury, and lead in the gastrointestinal (GI) tract, as well as their capacity to mitigate heavy metal-induced intestinal damage, with a single-strain product strategy in mind.Methods After initial selection of the strains for their in vitro detoxifying potential, we employed a dynamic Simulator of the Human Intestinal Microbial Ecosystem (SHIME (R)) model and each strain's survival, growth, and heavy metal detoxification capacity was assessed under sequential gastric, small-intestinal, and colonic conditions.Results Strain- and metal-specific differences in HMs sequestration emerged: L. plantarum LP14 and L. crispatus LCR04 showed robust persistence and significantly reduced HMs bioavailability, whereas L. acidophilus LA12 displayed minimal detoxification under GI simulation. Mechanistically, only the strains that proliferated in the colonic phase achieved substantial HM removal, underscoring the importance of metabolic activity in situ. In a gut ex vivo system (GEVS), heavy metal exposure alone compromised epithelial barrier integrity and triggered pro-inflammatory responses. Pre-incubation of the HMs with each of the probiotic strains markedly alleviated these effects, restoring intestinal permeability and cytokine profiles.Discussion Overall, the results demonstrate a novel probiotic-based intestinal bioremediation strategy and highlight the translational potential of targeted single-strain probiotic interventions, reducing heavy metal exposure to protect gut health.