Kraiser, T., Stuardo, M., Manzano, M., Ledger, T., & Gonzalez, B. (2013). Simultaneous assessment of the effects of an herbicide on the triad: rhizobacterial community, an herbicide degrading soil bacterium and their plant host. Plant Soil, 366(1-2), 377–388.
Abstract: This work addresses the relevant effects that one single compound, used as model herbicide, provokes on the activity/survival of a suitable herbicide degrading model bacterium and on a plant that hosts this bacterium and its bacterial rhizospheric community. The effects of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), on Acacia caven hosting the 2,4-D degrading bacterium Cupriavidus pinatubonensis JMP134, and its rhizospheric microbiota, were simultaneously addressed in plant soil microcosms, and followed by culture dependent and independent procedures, herbicide removal tests, bioprotection assays and use of encapsulated bacterial cells. The herbicide provokes deleterious effects on the plant, which are significantly diminished by the presence of the plant associated C. pinatubonensis, especially with encapsulated cells. This improvement correlated with increased 2,4-D degradation rates. The herbicide significantly changes the structure of the A. caven bacterial rhizospheric community; and it also diminishes the preference of C. pinatubonensis for the A. caven rhizosphere compared with the surrounding bulk soil. The addition of an herbicide to soil triggers a complex, although more or less predictable, suite of effects on rhizobacterial communities, herbicide degrading bacteria and their plant hosts that should be taken into account in fundamental studies and design of bio(phyto)remediation procedures.
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Ortega-Martinez, E., Toledo-Alarcon, J., Fernandez, E., Campos, J. L., Oyarzun, R., Etchebehere, C., et al. (2024). A review of autotrophic denitrification for groundwater remediation: A special focus on bioelectrochemical reactors. J. Environ. Chem. Eng., 12(1), 111552.
Abstract: Groundwater is an important resource that can help in climate change adaptation. However, the pollution of these aquifers with nitrate is a widespread problem of growing concern. Biological denitrification using inorganic electron donors shows significant advantages in treating nitrate-polluted groundwater where organic matter presence is negligible. However, mass transfer limitations and secondary contamination seem to be the major hinderance to spread the use of these technologies. This could be solved by the use of bioelectrochemical systems (BES), which emerge as an attractive technology to solve these problems due to the reported low energy demand and high denitrification rates. However, technical and operational issues must be considered to replicate these results at full-scale. This review summarizes the biological basis of autotrophic denitrification and the key aspects of its application in bioelectrochemical systems. In addition, an estimation of the capital costs required for the implementation of a BES considering different population sizes and initial nitrate concentration in the ground-water is made.
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