Liquid-Liquid Extraction of Ferric Ions into the Ionic Liquids

Imidazolium ionic liquids containing acetylacetone, thenoyltrifluoroacetone, or 8-hydroxyquinoline, respectively, were used as the extracting agents for the separation of traces of iron (III) from its aqueous solutions with or without citric and oxalic acids. The results show that 8-hydroxyquinoline in imidazolium ionic liquids extract iron quantitatively from all the tested solutions including complexing ones, regardless of indications of unexpected iron behavior/speciation.

Liquid-Liquid Extraction of Ferric Ions Into the Ionic Liquids

(200 words) Imidazolium ionic liquids containing acetylacetone, thenoyltrifluoroacetone, or 8-hydroxyquinoline, respectively, were used as the extracting agents for the separation of traces of iron (III) from its aqueous solutions with or without citric and oxalic acids. The results show that 8-hydroxyquinoline in imidazolium ionic liquids extract iron quantitatively from all the tested solutions including complexing ones, regardless indications of unexpected iron behavior/speciation.

Decontamination Strategies Used for AFB Culture Significantly Reduce the Viability of Mycobacterium abscessus Complex in Sputum Samples from Patients with Cystic Fibrosis

Nontuberculous mycobacteria are important respiratory pathogens in patients with cystic fibrosis (CF). For diagnosis, international guidelines recommend culture of sputum that has been decontaminated via chemical treatment. Fifty-six sputum samples from 32 patients known to be previously colonized or infected with NTM were subdivided, and the aliquots were subjected to six different decontamination strategies, followed by quantitative culture for NTM. Thirty sputum samples contained Mycobacterium abscessus complex (MABSC) and 11 contained Mycobacterium avium complex (MAC). Decontamination strategies included treatment with N-acetyl L-cysteine with 2% sodium hydroxide (NALC-NaOH), 4% NaOH, 1% chlorhexidine, 0.5 N sulfuric acid, 5% oxalic acid, double decontamination with NALC-NaOH, followed by 5% oxalic acid, and saline (0.85%) as a control. The samples were also cultured directly with no treatment. Treatment with NALC-NaOH resulted in an average reduction in colony count of 87% for MABSC when compared with direct culture. NaOH at 4% caused a 98.3% average reduction in colony count. All treatments that included NaOH resulted in colony counts that were statistically lower than those obtained from direct culture or the saline-treated control (p < 0.05). Standard treatments using sulfuric or oxalic acids were less deleterious, but still resulted in an average reduction in colony count of at least 30%. The viability of MAC was much less affected by most decontamination treatments. In conclusion, the viability of MABSC was severely compromised by standard decontamination regimens. This supports recent evidence showing that optimal recovery of MABSC is achieved by culture on an appropriate selective agar without decontamination of sputum samples.

Chemical Removal of Cu and Zn from Swine Feces before Soil Application

Cu and Zn are known to be abundant in swine feces; hence, concentrations of these metals need to be lowered before swine feces are applied to land in order to prevent potential environmental problems. The main objective of this study was to develop an appropriate chemical process to remove Cu and Zn from swine feces using acid extractions. The removal efficiencies of Cu and Zn decreased in the order of H2SO4 > HNO3 > organic acids (citric and oxalic acids). Owing to the highest removal efficiencies of Cu and Zn by using H2SO4, it was selected for further elimination of Cu and Zn from swine feces. By using H2SO4, the optimal concentration, solid-to-liquid ratio, and reaction time were 2%, 1:50, and 8 h, respectively. At the optimum conditions, Cu concentration was decreased from 198 mg/kg to 40.1 mg/kg and Zn concentration from 474 mg/kg to 80.0 mg/kg, with removal rates of 79.7% and 83.1%, respectively. The low Cu removal efficiency, resulting from the strong complexation between Cu and organic matter of swine feces, was improved by the increase in the reaction time and H2SO4 solution concentrations. However, about half of the total nitrogen (TN) was also removed by using H2SO4, indicating that the swine feces treated with H2SO4 may have poor value as fertilizer. Additional studies are required to find an optimal method to maintain TN concentrations while simultaneously removing Cu and Zn.

Effect of frozen storage on some characteristics of kefir samples made from cow’s and goat’s milk

This study was aimed to determine the changes in kefir samples (CK and GK) made from cow’s and goat’s milk during frozen storage. The CK and GK samples were first stored at +4 °C for 14 and 21 days. Thereafter, all the samples were frozen at –35 °C for 24 h and kept at –18 °C for 45 days. There was no significant change in the fat, protein, acidity and pH values in both samples during the storage. The values of viscosity, WI and C* were higher in the CK samples while the syneresis value was higher in the GK samples throughout the frozen storage. The microorganisms ( Lactococcus spp., Lactobacillus spp., Leuconostoc spp., total mesophilic aerobic bacteria and yeasts) found in kefir made from goat's milk were more affected from the frozen storage. In both samples, the changes in organic acids and volatile flavor components were not significant during frozen storage, except acetic, citric and oxalic acids and acetaldehyde in GK sample. In addition, CK samples were preferred sensorially more by the panellists during frozen storage.

DOE Application for Analysis of Tribological Properties of the Al2O3/IF-WS2 Surface Layers

The article presents the effect of the processing parameters on tribological properties of aluminum oxide coatings Al2O3 doped with fullerene-like tungsten disulfide (IF-WS2) by design of experiment (DOE). Anodic oxidation of aluminum alloy was carried out in a ternary solution of SAS (sulfuric, adipic and oxalic acids) with IF-WS2. The thickness, geometric structure of the surface (SGP) and the tribological properties such as friction coefficient of tribological pair: Al2O3/IF-WS2 with polieteroeteroketon filled with graphite, carbon fiber and PTFE (named PEEK/BG) were investigated. The influence of electrolysis time and temperature on the tribological properties of coatings was studied using 2k factorial design. The stabilization of the friction coefficient indicates generation of steady anti-wear and anti-seizure Al2O3/IF-WS2 oxide coatings. DOE suggest i.e. high positive correlation between oxide thickness and time and temperature of the anodizing process.

Effects of Medium Components on Isocitric Acid Production by Yarrowia lipolytica Yeast

The microbiological production of isocitric acid (ICA) is more preferable for its application in medicine and food, because the resulting product contains only the natural isomer—threo-DS. The aim of the present work was to study ICA production by yeast using sunflower oil as carbon source. 30 taxonomically different yeast strains were assessed for their capability for ICA production, and Y. lipolytica VKM Y-2373 was selected as a promising producer. It was found that ICA production required: the limitation of Y. lipolytica growth by nitrogen, phosphorus, sulfur or magnesium, and an addition of iron, activating aconitate hydratase, a key enzyme of isocitrate synthesis. Another regulatory approach capable to shift acid formation to a predominant ICA synthesis is the use of inhibitors (itaconic and oxalic acids), which blocks the conversion of isocitrate at the level of isocitrate lyase. It is recommended to cultivate Y. lipolytica VKM Y-2373 under nitrogen deficiency conditions with addition of 1.5 mg/L iron and 30 mM itaconic acid. Such optimized nutrition medium provides 70.6 g/L ICA with a ratio between ICA and citric acid (CA) equal 4:1, a mass yield (YICA) of 1.25 g/g and volume productivity (QICA) of 1.19 g/L·h.