Biotechnologia Acta

22-33

Authors: T. P. Pirog, M. O. Shulyakova, L. V. Nikituk, S. I. Antonuk, I. V. Elperin

The aim of the work is to realize an alternative processing of toxic industrial waste into surfactants by strains Rhodococcus erythropolis IMV Ac-5017, Acinetobacter calcoaceticus IMV B-7241 and Nocardia vaccinii IMV B-7405 for remediation of environment. The studied strains were grown in liquid media containing such sources of carbon as waste (fried) sunflower oil, technical glycerol (by-product of biodiesel production), and aromatic compounds. The synthesis of surfactants was evaluated by emulsification index, conditional concentration of surfactants and concentration of extracellular surfactants, which was determined gravimetrically after their extraction from supernatant by the mixture of methanol and chloroform. The concentration of oil in water and soil was analyzed by gravimetric method after extraction with hexane. It was shown that with increasing concentration of the inoculum up to 10−15% and two times increase of nitrogen source content in medium containing 7−8% (v/v) of crude glycerol, concentration of surfactants synthesized by R. erythropolis IMV Ac-5017, A. calcoaceticus IMV B 7241 and N. vaccinii IMV B-7405 was 3.4; 5.0 and 5.3 g/l, respectively, that is 1.6−1.7 times higher as compared with values on basal medium with the same content of substrate. The maximum concentration (3.9−4.3 g/l) of surfactants synthesized by A. calcoaceticus IMV B-7241 on fried sunflower oil (4%) was achieved by using the inoculum grown on refined oil. The ability of R. erythropolis IMV Ac-5017, A. calcoaceticus IMV B-7241 and N. vaccinii IMV B-7405 to decompose aromatic compounds (phenol, naphthalene, toluene, hexachlorobenzene, benzoic and N-phenylanthranilic acid) with simultaneous synthesis of extracellular metabolites with surface-active and emulsifying properties was established. In the presence of surfactants in the form of culture liquid (5−10%), the degree of degradation of complex oil with heavy metal (Cu2+, Cd2+, Pb2+, 0.01−0.5 mmol) pollution in water (3−6 g/l ) and soil (20 g/kg) after 20 days was 82−92%. Bioconversion of industrial waste into surfactants for environmental technology allows recycling toxic waste, reducing costs of microbial surfactants and provides double effect of environmental purification, which is achieved in the production and use of microbial surfactants.

40-56

Authors: V. V. Turov, T. V. Krupska, А. P. Golovan, L. S. Аndriyko, М. Т. Кartel

The aim of the study was to identify the influence of hydrodensified nanosilica particles on the binding of water by milled plant raw materials in neutral and acidic media. Flowers of Hibiscus sabdariffa and Calendula officinalis were used as the model materials. According to the microphotographs and low temperature 1H NMR spectroscopy data, the silica film forms on the surface of the milled plant particles, and it can significantly influence their hydration. According to the suggested scheme, some of the water from the inner cavities of plant raw materials moves (as evidenced by the decreasing radius of water-filled pores) to the zone of contact of the composite components (the radius of clusters of adsorbed water increases). In studies of desorption of active substances from milled medicinal herbs and their composites by the initial and hydrodensified nanosilica, it has been shown that the formation of a composite significantly reduces the rate of desorption. Minimal desorption is observed in composites containing hydrodensified nanosilica. The studied composite systems are promising for biomedical researches.

67-74

Authors: N. O. Ryzhenko, V. M. Kavetsky

The aim of investigation was to develop a new approach in Cd, Zn, Cu, Pb phytotoxicity assessing. This approach provided the probit analysis using. Methods included probit analysis, thin layer chromatography, statistical methods (calculation of the least significant difference, correlation analysis). We applied «doze-effect» model to obtain the ranking of the metals according to their phytotoxicity in spring barley field. We offered to estimate the phytotoxicity by PhLD50 index. Research results were: graphic formalization of "dose-effect" dependence and calculation of phytotoxic doses (PhLD50 and PhLD95) for Cd, Cu, Pb, Zn in polluted soil. According to PhLD50 value we conducted a comparative assessment of Cd, Cu, Pb, Zn phytotoxicity relatively to spring barley. According to PhLD50 value metals could be ranked: Cd> Cu> Pb> Zn. The most toxic metal was Cd. PhLD values, on which the estimation of metals phytotoxicity, were: Cd – 50, Cu –129, Pb –537, Zn –603 mg / kg mobile forms in turf-podzol sandy loam soil. Our findings are relevant to estimating the metal hazard and controlling the condition of the crop growth.