Removal of nitrate-N by antibiotic exposed bacterial isolates from constructed wetlands

Abstract

Nitrate-N-removing bacterial strains were isolated from a constructed wetland soil treated with three ionophoric antibiotics: monensin, salinomycin and narasin. Five isolates were selected after initial screening for nitrogen removing potential. Nucleotide sequence analysis of the 16S rRNA gene showed that these isolates were highly similar to Bacillus, and Pseudomonas species. The isolates were assessed for their ability to grow in the presence of ionophoric antibiotics. All strains were found to withstand these pharmaceuticals. In particular, Bacillus subtilis strain BRAZ2B was found to thrive in the drugexposed wetland environment, showing higher nitrate removal rate than the uninoculated control. The strains were also assessed for nitrogen removal potential under three different C/N ratios: 4, 8 and 12; optimum removal efficiency was observed at C/N 8 for most isolates.

Implications of Benzoate Induced Alterations in Cell Morphology and Physiology in Pseudomonas aeruginosa TMR2.13 for Potential Application in Bioremediation and Monitoring Approaches

“…However, several studies have shown that both oxygen and nitrate can function concurrently during respiration irrespective of the availability of oxygen [20,22]. Such a phenomenon is termed as aerobic denitrification and is more prevalent in Gram negative bacteria such as P. aeruginosa [34]. Our results reflect that although static conditions were conducive for denitrification in strain TMR2.13, aeration created favourable conditions for growth of the aerobic culture.…”

A Literature Review of Wetland Treatment Systems Used to Treat Runoff Mixtures Containing Antibiotics and Pesticides from Urban and Agricultural Landscapes

“…Studies were also removed if only nutrient removal was analyzed without the presence of pesticides or antibiotics. For example, analyzed N removal in the presence of antibiotics; thus, the study was retained for further analysis even though the antibiotic removal potential was not specified [43]; however, Jia et al (2021) investigated N removal and poly-3-hydroxybutyrate-co-3hydroxyvalerate/polylactic acid removal in the absence of any pesticides or antibiotics, so this study was removed from further analysis [44]. Review articles were also excluded from the analysis, given that new research on the topic was not conducted; rather, a summary of the existing research was reviewed and/or meta-analysis was completed.…”

“…Review articles were also excluded from the analysis, given that new research on the topic was not conducted; rather, a summary of the existing research was reviewed and/or meta-analysis was completed. From this, there were 181 primary studies used for further analysis [3,16,23,25,30,32,43,. Each study was evaluated to ensure it pertained to wetland treatment of non-point sources.…”

“…used in 11% of the studies (Table 6). It is important to note that not all studies used wetland plants [43,83,89] or identified the specific plant species within the wetland system [148,159,179]. Also, not all primary studies that specified the plant species present in the wetland system analyzed the impact of phytoremediation as a removal mechanism [21,173,205].…”

Spatial and seasonal analysis of antimicrobials and toxicity tests with Daphnia magna, on the sub-basin of Piracicaba river, SP, Brazil

“…Additionally, consideration over contamination with pharmaceuticals have been increasing since these compounds are, also, considered "pseudo-persistent" pollutants due to their continuous insertion in the environment [6]. These even in low concentrations, have the capacity to affect the exposed biota [7], though studies have reported that some of these compounds can be degraded by microbial activity [8,9] or even natural photolysis reactions [10]. However, occasionally the intermediaries generated by these natural routes can be more toxic and persistent in the environment [11].…”