Pseudomonas sp.ZXY-1,a newly isolated and highly efficient atrazine-degrading bacterium,and optimization of biodegradation using response surface methodology

Atrazine, a widely used herbicide, is increasing the agricultural production effectively, while also causing great environmental concern. Efficient atrazine-degrading bacterium is necessary to removal atrazine rapidly to keep a safe environment. In the present study, a new atrazine-degrading strain ZXY-1, identified as Pseudomonas, was isolated. This new isolated strain has a strong ability to biodegrade atrazine with a high efficiency of 9.09 mg/L/hr.Temperature, p H, inoculum size and initial atrazine concentration were examined to further optimize the degradation of atrazine, and the synthetic effect of these factors were investigated by the response surface methodology. With a high quadratic polynomial mathematical model（R^2= 0.9821） being obtained, the highest biodegradation efficiency of 19.03 mg/L/hr was reached compared to previous reports under the optimal conditions（30.71°C, pH 7.14, 4.23%（V/V） inoculum size and 157.1 mg/L initial atrazine concentration）.Overall, this study provided an efficient bacterium and approach that could be potentially useful for the bioremediation of wastewater containing atrazine.

A new hydrophobic deep eutectic solvent composed of menthol and tris(2-ethylhexyl) phosphate for solvent bar microextraction of parabens from biological fluids

Parabens are antimicrobial preservatives with extensive applications in cosmetics,toiletries,pharmaceuticals,and food.Considering the legitimate concerns relating to their potential to disrupt multiple endocrine functions,it becomes imperative to prioritize the development of innovative bioanalytical techniques for effectively monitoring their presence in biological samples.In this study,an efficient solvent bar microextraction(SBME)was established,utilizing new hydrophobic deep eutectic solvents(DEs)to determine methylparaben and propylparaben in urine and plasma samples.The DEs comprising menthol and tris(2-ethylhexyl)phosphate(M-TEHP)at various molar ratios were synthesized for the first time to enhance the extraction capacity and promote the eco-friendliness of the DE used as an extraction solvent.Fourier-transform infrared(FT-IR)and proton nuclear magnetic resonance(1H NMR)spectroscopies were employed to confirm and investigate the properties of the successful synthesis(M-TEHP)DE at a molar ratio of 1:1.The synthesized DE exhibits low microbial toxicity and can be considered an eco-friendly solvent for extraction.Furthermore,quantum-chemical calculations were utilized to predict synthesized DE's structure and interaction energy with selected parabens.The influential operational factors of DE-SBME on the extraction efficiency(EE%)of both parabens were evaluated using response surface methodology based on central composite design,and a total of 30 extraction tests were conducted to determine the optimal conditions.The optimized DE-SBME,in combination with HPLC-DAD,exhibited low detection limits(0.54–0.91μg L^(−1)),excellent linearity(R^(2)≥0.9993),precise results(RSDs≤7.6%),satisfactory recoveries(92–97%)and negligible matrix effects.Hence,it had remarkable effectiveness and applicability in determining selected parabens in real urine and plasma samples.