Utilization of Fenton-like reaction for antibiotics and resistant bacteria elimination in different parts of WWTP.

Utilization of relatively low-cost modification of Fenton reaction for the elimination of selected antibiotics and resistant coliforms in different part of wastewater treatment plant (WWTP) was studied. The concentration of antibiotics and occurrence of resistant gems in different stages of WWTP in the capital city of Slovakia - Bratislava was analyzed by LC-MS/MS technique. Consequently, Fenton-like reaction was applied for the elimination of chemical and biological contaminants. Comparative study with classical Fenton reaction was also done. Very high concentrations of clarithromycin, ciprofloxacin and azithromycin in influent water were found. Coliform bacteria were predominantly resistant to ampicillin, ciprofloxacin and gentamicin. After the mechanical stage, the concentration of antibiotics in water was significantly decreased because of the sorption during this step. Biological step degraded 12 types of antibiotics. Analyses of effluent water showed very bad elimination of azithromycin (919ng/L) and clarithromycin (684ng/L). Contrary, ciprofloxacin was removed with very high efficiency (95%). The number of resistant bacteria was also significantly decreased in effluent water. In the case of Escherichia coli only ampicillin and gentamicin resistance bacteria were detected. Our results show that antibiotics as well as resistant bacteria were eliminated by the modification of classical Fenton reaction with high efficiency. The modification of the Fenton reaction can decrease the process wages, environmental impact. Moreover, the degradation process was easily controlled, monitored and tuned.

Phosphatidylserine content is a more important contributor than transmembrane potential to interactions of merocyanine 540 with lipid bilayers.

Several factors, including the exposure of the negatively charged PL and transmembrane potential (TMP), may affect the binding of merocyanine 540 dye (MC540) to membrane lipids. Our aim was to quantify the significance of each of these two determinants in MC540 interactions with phosphatidylserine:phosphatidylcholine (PS/PC) vesicles. The effects of the altered PS content (PS/PC molar ratio: 5:95, 10:90 and 20:80) and TMP on MC540 binding were monitored using flow cytometry. Rapid [K(+)] flux across the vesicle membrane lipid bilayer was generated using valinomycin. We showed that the increased PS content leads to attenuated MC540 binding, while having no influence on the dynamic parameters of PS/PC vesicle membranes (electron spin resonance (ESR) spectrometry). Higher [K(+)](out) makes PS/PC liposomes bind more MC540, which implies that TMP-which becomes more positive inside the vesicles-favours the interactions of MC540 with the PL bilayer. Overall, the variability attributed to MC540-PL interactions is explained only to a minor extent by the generated TMP (7%) and largely by the variations in PS content (by up to 60%). In conclusion, the content of negatively charged PL is more important than TMP in determining the interactions of MC540 with PS/PC membranes.