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The purpose of the study was to identify the infl uence of reactive mixture concentration (23-48 g/100 mL), pH (6.5-9.0), presence of NaCl (0.05-0.25 mol/L) and enzyme dose (2850-28,500 LAU/100 g of lactose) on the synthesis of galactosyl mannitol derivative using β-galactosidase from Kluyveromyces lactis. The use of the enzyme dose ranging from 2850 to 11,400 LAU/100 g lactose allowed obtaining gal-mannitol at the level of 21.8% total saccharides; higher doses intensifi ed product decomposition. An increase in the concentration of the reactive mixture had a positive impact on the quantity of gal-mannitol obtained every single time, i.e. 4.39 g were obtained from 100 mL of a 23 g/100 mL solution and over 10 g were obtained from a 48 g/100 mL solution. A relatively low increase in product quantity (by ca. 5%) occurred after the pH was increased from 6.5 to 9.0. The use of NaCl rendered better results. An increase in the maximum content of gal-mannitol in the total sugar by 12.8% was observed at the concentration of 0.25 mol/L.

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In this study, the extraction of nickel(II) ions from sulphate and sulphate/chloride solutions with 2-, 3-, and 4-pyridylketoximes was investigated. The effect of different variables influencing the extraction of nickel(II) ions such as the extractant structure and the concentration of hydrogen ion, sulphate, and chloride ions have been studied. The shaking time and temperature also influenced metal ion removal. It was found that the hydrophobic 2-pyridylketoximes are the most effective extractants for nickel ions from sulphate/chloride solutions. The discussion also includes the mechanism of nickel(II) complexation by the hydrophobic pyridylketoximes and the speciation of nickel(II) in the presence of chloride and sulphate ions.

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The goal of this work was to study the extraction of zinc(II) ions from chloride solutions with the hydrophobic quaternary 3-pyridinium ketoximes. The influence of pH, contact time, concentration of chloride ions and extractant, as well as the effect of ligand structure on the zinc(II) extraction were investigated. The studies showed that at 4 M Cl − , regardless of the acidity of the aqueous chloride solutions and type of anions attached to pyridinium ring, the zinc(II) extraction increased with increasing length of the alkyl chain. Furthermore, the extraction from a multielemental solution is selective and the created complex can be decomposed after being shaken with the aqueous solutions of sodium sulfate or sodium hydroxide. It was also indicated that the zinc(II) extraction by the hydrophobic quaternary 3-pyridinium ketoximes proceeded via an ion-exchange mechanism, and the molar ratio of zinc to ligand to chloride in the complex molecule was 1:1:2, 1:1:3, and 1:2:2.

SummaryBionic acids are bioactive compounds demonstrating numerous interesting properties. They are widely produced by chemical or enzymatic oxidation of disaccharides. This paper focuses on the galactosyl derivative of gluconic acid as a result of a new method of bionic acid synthesis which utilises the transglycosylation properties of β-galactosidase and introduces lactose as a substrate. Products obtained in such a process are characterised by different structures (and, potentially, properties) than those resulting from traditional oxidation of disaccharides. The aim of this study is to determine the effect of selected parameters (concentration and ratio of substrates, dose of the enzyme, time, pH, presence of salts) on the course of the reaction carried out with the enzymatic preparation Lactozym, containing β-galactosidase from Kluyveromyces lactis. Research has shown that increased dry matter content in the baseline solution (up to 50 %, by mass per volume) and an addition of NaCl contribute to higher yield. On the other hand, reduced content of the derivative is a result of increased pH from 7.0 to 9.0 and an addition of magnesium and manganese salts. Moreover, exceeding the β-galactosidase dose over approx. 35 000 U per 100 g of lactose also leads to reduced yield of the process. The most favourable molar ratio of sodium gluconate to lactose is 2.225:0.675. Depending on the conditions of the synthesis, the product concentration ranged between 17.3 and 118.3 g/L of the reaction mixture, which corresponded to the mass fraction of 6.64-23.7 % of dry matter. The data obtained as a result of the present study may be useful for designing an industrial process.