Search

In this study, initially 11 different bacterial strains were tested for the degradation capabilities against Basic Orange 2 dye. In initial screening with 78.90% degradation activity, Escherichia coli emerged as the most promising strain to degrade the selected dye, and was then employed in subsequent experiments. For further enhancing the degradation capability of selected bacteria, the effects of various physicochemical parameters were also evaluated. Among the tested parameters, 20 ppm dye concentration, 1666 mg/L glucose concentration, a temperature of 40 °C, 666 mg/L sodium chloride concentration, pH 7, 1000 mg/L urea concentration, a 3-day incubation period and the use of sodium benzoate as a redox mediator (666 mg/L) were found to be ideal conditions to get the highest decolorization/degradation activities. Finally, all the mentioned parameters were combined in a single set of experiments, and the decolorization capacity of the bacteria was enhanced to 89.88%. The effect of pH, dye concentration, incubation time and temperature were found to be responsible for the optimum degradation of dye (p < 0.05), as predicted from the ANOVA (analysis of variance) of the response surface methodology. The metabolites were collected after completion of the process and characterized through Fourier transform irradiation (FTIR) and gas chromatography mass spectrometry (GC-MS). From the data obtained, a proposed mechanism was deduced where it was assumed that the azo bond of the dye was broken by the azoreductase enzyme of the bacteria, resulting in the formation of aniline and 3, 4-diaminobezeminium chloride. The aniline was then further converted to benzene by deamination by the action of the bacterial deaminase enzyme. The benzene ring, after subsequent methylation, was transformed into o-xylene, while 3, 4-diaminobezeminium chloride was converted to p-xylene by enzymatic action. These findings suggest that Escherichia coli is a capable strain to be used in the bioremediation of textile effluents containing azo dyes. However, the selected bacterial strain may need to be further investigated for other dyes as well. [ABSTRACT FROM AUTHOR]

Three natural extracted oils from Citrus reticulata peels, C. aurantifolia leaves, and Linum usitatissimum (linseeds) were used as antifungal agents against the growth of Aspergillus flavus and Penicillium chrysogenum. The following main compounds (determined via gas chromatography--mass spectrometry) were found. The essential oil (EO) from C. aurantiifolia leaves contained limonene (22.96%), geranyl acetal (13.53%), and geraniol acetate (13.33%); the n-hexane oil from C. reticulata peels contained methyl-13-cyclopentyltridecanoate (16.74%), and D-limonene (16.06%); and linseed oil contained linoleic acid (27.36%), and oleic acid (19.01%). The inhibition of fungal growth significantly was reached 100% against A. flavus at all tested C. aurantifolia leaf EO concentrations and at a concentration of 2000 µL/mL for linseeds oil. The growth inhibition reached 100% against P. chrysogenum with C. aurantifolia leaf EO concentrations of 125-2000 µL/mL. Citrus reticulata peel EO had 100% growth inhibition of P. chrysogenum at concentrations of 2000 µL/mL and 1000 µL/mL, while linseeds oil had 100% growth inhibition at 2000 µL/mL. Thermogravimetric analysis showed that C. aurantifolia EO yielded the greatest thermal stability and color change protection to cotton pulp, while linseed oil was found to protect wood pulpbased and historical papers. [ABSTRACT FROM AUTHOR]

In this study, we have prepared anatase titanium (IV) oxide warped reduced graphene oxide nanocomposites (TiO2-rGO NC) using ultrasonic methodology. The morphology of the TiO2-rGO NC was studied using FESEM and TEM. In addition, XRD, Raman, thermogravimetric analysis (TGA) and XPS are used to analyze the crystallinity and chemical composition of the TiO2-rGO NC. We have also investigated the electrochemical behavior of the as-prepared NCs with electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and different pulse voltammetry techniques (DPV). The TiO2-rGO NC modified electrode shows the lower charge transfer resistance (Rct) of 62.87 Ω. Next, the glassy carbon electrode (GCE) was modified with sonochemically prepared TiO2-rGO NC and used to determine the electrocatalytic reduction of nitrofurazone (NTF). Thus, the proposed sensor established the wider covering range (WCR) of 0.01 to 380 µM and an excellent detection limit of 2.28 nM. Finally, the TiO2-rGO NC/GCE was applied to determine the NTF in real samples, including crayfish and human blood serum samples, which acquired good found and recovery values. [ABSTRACT FROM AUTHOR]

Background: The use of carbapenem antibiotics in the treatment of serious Gram-negative bacterial infections is under threat due to the emergence of the blaIMP gene amongst the bacterial pathogens., Methods: The present descriptive cross-sectional study aimed to determine the occurrence of the blaIMP gene and minimum inhibitory concentrations (MICs) of the bacterial pathogens. The carbapenem-resistant isolates were screened out for the detection of MBLs by using the modified Hodge test and disk potentiation method. MBL producing strains were tested for the presence of the blaIMP gene by using PCR technique. The MICs of the blaIMP gene positive bacterial isolates were detected on the Vitek 2 system (bioMerieux)., Results: The primary source of MBLs and blaIPM gene carrying bacterial pathogens was blood (38.5%). We isolated 104 bacterial isolates in the initial screening of carbapenem resistance. Metallo-beta-lactamases (MBLs) were detected in 76 (73%) of the isolates which predominantly included 27 (26%) Klebsiella pneumoniae, 20 (19.2%) Acinetobacter baumannii, 16 (15.4%) Pseudomonas aeruginosa, and 11 (10.6%) E. coli while the other Gram-nega-tive MBL producing bacteria were few in number. The blaIPM gene was detected in 1 (1.3%) case of Acinetobacter baumannii and 1 (1.3%) case of Stenotrophomonas maltophilia. These strains were found to be multi-drug resistant with high MICs (≥ 8 to ≥ 256 µg/mL) against the majority of the drugs., Conclusions: The emergence of the blaIPM gene is a matter of serious concern as it left us with limited treatment options of minocycline, tigecycline, and levofloxacin. The horizontal transfer of blaIPM gene in other Gram-negative isolates can lead the epidemics of multidrug resistance.