Chemistry. Ecology. Biotechnology

A.Furina, A. Maksimov, V. Basov

APPLICATION OF PENICILLIUM GENUS FUNGI OXIDASE

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УДК 549.755.211

E.А. Nosenko, G.V. Leontjevа, V.V. Volkhin

REMEDIATION OF THE SOILS CONTAMINATED BY HEAVY METALS USING SORPTION-ACTIVE FORM

OF MAGNESIUMAMMONIUMPHOSPHATE

Perm National Research Polytechnic University

Heavy metals are among the major biosphere pollutants. Physiological effect of metals on a human body and animals is various, also it depends on metal nature, type of connection in which it exists in the environment, and also its concentration.

Heavy metals do not decay in the soil that complicates soil cleaning of them. Removal of heavy metals is a difficult and expensive process. It is more expedient to transfer them to an inactive state that will allow reducing their bioavailability.

Ameliorants are used to stabilize heavy metals, they occlude and strongly hold ions of metals. Magnesiumammoniumphosphate is a perspective ameliorant stabilizer (MAP), accumulated as a waste in technology of sewage treatment from ammonium ions.

The purpose of this work is receiving MAP sorption-active form and developing a technique for their application as an ameliorant stabilizer to remediate the soil polluted by nickel ions.

In order to achieve the goal preparation conditions of the MAP sorptionactive form have been defined. Sorption properties of the received MAP samples are checked by the sorption of nickel ions (II) from water environments. The MAP sorption functions in the soil polluted by nickel ions (II) depend on a number of conditions: doses of the injected drug, humidity of the soil, interaction length. The assessment of the decrease of nickel bioavailability in soil solution is carried out on catalase activity.

It is planned to develop the technological scheme of sorptionactive MAP receiving for its use as an ameliorant stabilizer in the soil polluted by nickel ions.

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УДК 543.86

A.V. Bazhutin, A.A. Rukavicyna, L.D. Asnin

OPTIMIZATION OF THE CONDITIONS OF SCREENING TESTS FOR STYDING ENANTIOSELECTIVE MICROBIAL TRANSFORMATION OF AMINO ACIDS

Perm National Research Polytechnic University

The studies of microbiological processes involving homochiral substrates (optically pure enantiomers of chiral compounds) draw an increased interest in view of using such systems for testing homochiral medicinal compounds and developing of biotechnological platforms for enantioselective biosynthesis. Screening tests are aimed at identification of the most perspective microorganisms for further detailed study and at preliminary assessment of the impact of various factors on the studied reaction's characteristics. Requirements of accuracy, time and chemicals efficiency, and convenience of automation are imposed on them. The test procedure has to exclude the non-biochemical racemization of a substrate if enantiomers are examined.

The conditions of screening tests for the study of amino acids' enantioselective biodegradation are discussed in the present work, using phenylalanine as a case study. Bacteria of the Pseudomonas, Rhodococcus and Bacillus genera are taken as model microorganisms. Bacteria were stored in a solid medium and resowed 3 days prior to tests. The process was carried out in a Raymond nutrient medium containing 1% of substrate (L- or D-phenylalanine). It is shown that sterilization and sample preparation does not lead to the racemization of the substrate. Reaction was carried out in test tubes with a volume of the reaction mixture of 2 ml which secured a low consumption of reagents. The experimental procedure involves the washout of microorganisms from a slanted agar by the nutrient medium, addition of sterile alkali solutions and acid to achieve a desired pH, and aeration of test tubes on a shaker at 29 °С. Op-

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timum time of experiment is 48 hours. It is recommended to take an intermediate sample in 24 hours, but reliability of the bacterial activity assessment in this case is not guaranteed. After sampling, the specimen is purified by ultracentrifugation and filtered with a syringe filter with a pore size of 0.45 μm.

Specification of the substrate content was carried out on the Shimadzu LC-20ADXR chromatograph with a diode array detector using the ShimPack XR-ODS II reverse phase column at 25 °C. The optimization of separation conditions for sample components was performed by varying the composition of the aqueous-organic mobile phase, the nature of an organic solvent (acetonitrile or methanol) and flow rate (Fv). An acetate buffer solution (pH = 5.2, Fv = 0.3 ml/min) prepared in a water-methanol (60:40, v/v) solution was used as the mobile phase. The analysis time did not exceed 5 min. The 221 nm wavelength was used to record chromatograms that allowed us to detect the appearance of products of phenylalanine degradation, and the 254 nm wavelength was used to eliminate their impact on the peak of phenylalanine.

УДК 539.216.2:544.722.1

A.S. Averkina, V.V. Volkhin

INFLUENCE OF VARIOUS FACTORS

ON THE FORMATION AND STABILITY OF FILMS CONSISTING OF HYDROPHOBIC PARTICLES

Perm National Research Polytechnic University

Dust and smoke sediments on the water surface are considered to be a natural phenomenon. These sediments are small solid-phase particles of mineral and organic origin that have ability to rest on the air-to-water interface due to their fine dispersion. Similarly, the low weight hydrophilic small particles, as well as hydrophobic ones, stay at the interfacial surface.

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The ability of fine particles to form various surfaces (membranes, small particles clusters) is explained by their nature.

In this paper we focus on the study of fine hydrophobic particles behavior on the air-to-water interfacial surface. As model particles that define a degree of particle's hydrophobicity, various types of alkyl 3-chlorosilane modified silica particles (Diasorb – 130) are used. The experiments were carried out in the Biostat A Plus aggregate (Sartorius, Germany). An absorber allows setting and controlling the parameters of the liquid phase, namely temperature and mixing.

We have found that to reduce the contact area with the water surface, the hydrophobic particles may form small clusters on the interface (given the low motion intensity of surface flow), or they can unify into a membrane (given the high motion intensity of surface flow). The area of such membrane reduces with increase in length of the hydrocarbon radical, applied on the surface of silica particles of equal mass (Table 1).

T a b l e 1

The area of membrane on the interface, depending on the degree of hydrophobicity of the particles; silica in amount of 20 mg and liquid phase stirring speed 200 rpm

The experiment has shown that membrane formation and its dimension also depends on the mixing intensity of the liquid phase and on the amount of hydrophobic particles on the interface.

One of the experiment's objectives is to determine the effect of substances dissolved in a liquid phase on membrane formation. During the experiment the dependence of membrane formation on the type of soluble substances was obtained (the carboxylic acids with hydrocarbon

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radicals of a different molecular mass given as an example). The results are presented in Table 2.

Based on the results, we can conclude that the larger molecular mass of hydrocarbon radical is in the acid and the greater acid concentration is in the liquid phase, the less dense the membrane becomes, i.e. membrane's particles are further away from each other. The appearance of organic acid molecules near the interface leads to a spatial redistribution of hydrophobic particles on the surface of the liquid phase.

T a b l e 2

Area of the membrane of Diasorb-130-S16T particles; silica in amount of 20 mg and liquid phase stirring speed of 200 rpm

Note: "–" – studies have not been conducted

The results of these experiments can be predictive of the behavior of hydrophobic particles on the interface depending on the intensity of mixing, composition of the liquid phase, and on the nature of the particles forming the membrane.

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