Advanced oxidation processes against alkyl phenols in groundwater samples

Spectrophotometric examinations showed the presence of phenolic compounds in the organic residue collected from four groundwater resources located in vicinity of an oil refinery at the outskirt of Tehran. The average concentration of total phenolic compounds was about 0.38 mg.L-1 in these samples using Folin-Ciocalteu method. GC-Mass analysis disclosed that alkylphenols were the major phenolic contaminants in the samples. Evaluation of the Advanced Oxidation Processes (AOPs) efficacy for removal of alkylphenols from real water samples is a hot topic of recent Environmental Research due to the decomposition of these compounds in soil and by microorganisms which may results in the formation of structures more resistance against various types of oxidation. To explore the efficacy of AOPs for removal of alkylphenols from the examined groundwater resources, the optimal conditions for three important AOP including Fe2+/H2O2/UV (Photo-Fenton), O3/UV and O3/UV/H2O2 were first sought using a recalcitrant lab sample containing different aromatic compounds with total concentration of 2 mg L^-1. Consequently, two methods of O3/UV (2 mg L-1 O3, 15 min UVC), and O3/UV/H2O2 (2 mg L^-1 O3, 5000 mg L^-1 H2O2, 15 min UVC) were selected to be examined on the real samples. Although the selected methods were quantitatively effective on the lab sample, they resulted in average removal efficiencies of 79.71% and 84.16% on the real samples, respectively. With respect to the safety regulations, costs and easiness of implementation, the O3/UV method seems to be more promising for large-scale plans

Detailed Investigations on the Solid Cell Culture and Antimicrobial Activities of the Iranian Arnebia euchroma

In pursuit of strong shikalkin-producing cell lines, seeds of the Iranian Arnebia euchroma were collected from Dena altitudes in the central Zagross. Chemical analysis showed that the dried root of the plant contained about 8.5% (w/w) shikalkin pigment. The root explants of the young plantlets, obtained from the germinated seeds, were used for establishing callus. Then, parameters effective on proliferation and pigment production of the resulting calli were studied in detail. Accordingly, two modified media called mLS and mM9 were optimized for propagation and pigment production, respectively. Using these media, the biomass of the A.euchroma calli was increased to 600%, and the pigment production reached to a maximum of 16.3 mg per gram of the wet biomass in a period of a subculture (21 days). Parallel to these experiments, the antimicrobial activity of shikalkin pigment was examined on some fungi and Gram-positive and Gram-negative bacteria. Results indicated that the pigment was almost ineffective on fungi and Gram-negative bacteria, but it was meaningfully effective against Micrococcus luteus

Calorimetric, spectrophotometric and circular dichroism studies on the impact of sodium dodecyl sulfate on the mushroom tyrosinase structure

Mono-oxygenase (also called cresolase) activity of mushroom tyrosinase (MT) can be optimized in the presence of 0.35 mM of sodium dodecyl sulfate (SDS). Spectrophotometric kinetic studies on MT revealed that the optimum temperature for the cresolase reaction was about 35°C both in the absence and presence of SDS. Circular dichroism studies of the thermal denaturation of MT between 20°C to 90°C disclosed that the secondary structure experienced minor changes in the presence of SDS, while changes in the tertiary structure were significant. The tertiary structure was destabilized by 15.7 kJ/mol in the presence of SDS. Differential scanning calorimetric studies on MT, in the absence and presence of SDS, produced two different profiles. The former showed an irreversible peak with Tm at 72°C and the latter showed a reversible peak with Tm about 37°C. Deconvulation analysis of the reversible peak was in good agreement with three transitions with Tm values of 33, 36 and 39°C, respectively. Considering the results of the kinetic studies, CD, and differential scanning calorimetry, it was concluded that the best performance of the cresolase activity of MT was achieved after a spatial change in the tertiary or quaternary structure caused by SDS. To reach this particular conformation, three structural transitions happen, which could be referred to the changes in the spatial positions of the domains or its subunits