Within the MICROLIFEPAQS project, new Enzyme-Based Kinetics linking RDase functional expression in Dehalococcoides to chlorinated ethene biodegradation were developed. The model introduces key features that were never incorporated in previous attempts, making it more flexible: (i) the presence of homologous functional genes expressed by different Dehalococcoides strains at a community level, (ii) nonunique transcription regulation mechanisms in chlorinated ethene-respiring bacteria, and (iii) degrading explicitly growing on multiple chlorinated ethenes. Furthermore, these kinetics were successfully integrated for the first time into full-aquifer-scale 1D RTMs simulating chlorinated ethene plumes, additionally considering the partitioning of Dehalococcoides the solid and aqueous phase, as experimentally observed in the literature. To test this novel modelling approach, molecular biological analyses were performed on newly collected groundwater samples from the test site (i.e. the Grindsted plume). These data were used to implement and calibrate the 1D RTM of the Grindsted plume, which was used to interpret for the first time the observed chemical and biomarker patterns and allowed providing insights into the effect of local field condition on Dehaloccoccoides ecological strategy, metabolic regulation dynamics, and biotic reductive dechlorination efficiency.
Key scientific innovations include:
1) The development of EBK, a flexible model linking chlorinated ethene biodegradation to specific metabolic functions (i.e. functional gene expression and enzyme production) in Dehalococcoides.
2) Successful integration in RTMs simulating chlorinated ethene plumes' evolution
3) Successful application of this modeling approach to a real case study, such as the Grindsted plume.
4) Insights into how environmental conditions, such as nutrient availability, chemical gradients, and aquifer hydrodynamics, influence microbial activity and biotic chlorinated ethene breakdown.
These advancements have implications for both science and society. For researchers, the models provide a powerful tool to study and predict biotic degradation processes in contaminated sites, especially reductive dechlorination. For specialists, they offer a robust modeling framework to design and optimize remediation strategies. On a broader scale, the project aligns with the European Union and United Nations’ objectives to eliminate environmental pollution in the next future. By enhancing our ability to manage and remediate polluted groundwater, MICROLIFEPAQS contributes to safer water resources, healthier ecosystems, and improved quality of life. Through its interdisciplinary approach and innovative outcomes, MICROLIFEPAQS sets a new benchmark for environmental research, paving the way for future advancements in hydrobiogeochemical reactive transport modelling.
