Dissipation of pesticides by stream biofilms is influenced by hydrological histories.

To evaluate the effects of hydrological variability on pesticide dissipation capacity by stream biofilms, we conducted a microcosm study. We exposed biofilms to short and frequent droughts (daily frequency), long and less frequent droughts (weekly frequency) and permanently immersed controls, prior to test their capacities to dissipate a cocktail of pesticides composed of tebuconazole, terbuthylazine, imidacloprid, glyphosate and its metabolite aminomethylphosphonic acid. A range of structural and functional descriptors of biofilms (algal and bacterial biomass, extracellular polymeric matrix (EPS) concentration, microbial respiration, phosphorus uptake and community-level physiological profiles) were measured to assess drought effects.

Effect of subtherapeutic and therapeutic sulfamethazine concentrations on transcribed genes and translated proteins involved in Microbacterium sp. C448 resistance and degradation.

Microbacterium sp. C448, isolated from a soil regularly exposed to sulfamethazine (SMZ), can use various sulphonamide antibiotics as the sole carbon source for growth. The basis for the regulation of genes encoding the sulphonamide metabolism pathway, the dihydropteroate synthase sulphonamide target (folP), and the sulphonamide resistance (sul1) genes is unknown in this organism.

Glyphosate-degrading behavior of five bacterial strains isolated from stream biofilms.

The present study investigates the individual degrading behavior of bacterial strains isolated from glyphosate-degrading stream biofilms. In this aim, biofilms were subjected to enrichment experiments using glyphosate or its metabolite AMPA (aminomethyl phosphonic acid) as the sole phosphorus source. Five bacterial strains were isolated and taxonomically affiliated to Ensifer sp.

Potential of preventive bioremediation to reduce environmental contamination by pesticides in an agricultural context: A case study with the herbicide 2,4-D.

One of the major problems with pesticides is linked to the non-negligible proportion of the sprayed active ingredient that does not reach its intended target and contaminates environmental compartments. Here, we have implemented and provided new insights to the preventive bioremediation process based on the simultaneous application of the pesticide with pesticide-degrading microorganisms to reduce the risk of leaching into the environment. This study pioneers such a practice, in an actual farming context.

Dissolved organic matter does not promote glyphosate degradation in auto-heterotrophic aquatic microbial communities.

Environmental dissolved organic matter (DOM) has been proved to increase microbial population sizes and stimulate the degradation of some pesticide molecules. Among these molecules, the present study investigated the biodegradation of the herbicide glyphosate depending on photoautotrophs DOM supply in a microbial consortium isolated from river biofilms. Degradation experiments in the laboratory were performed in dark and light conditions, as well as after antibiotic supply, in order to characterize the eventual interactions between photoautotrophs and heterotrophs activity during glyphosate degradation.