[Destruction of oil in the presence of Cu2+ and surfactants of Acinetobacter calcoaceticus IMV B-7241, Rhodococcus erythropolis IMV Ac-5017 and Nocardia vaccinii IMV B-7405].

The effect of copper cations (0.01-1.0 mM) and surface-active agents (surfactants) of Acinetobacter calcoaceticus IMV B-7241, Rhodococcus erythropolis IMV Alc-5017 and Nocardia vaccinii IMV B-7405 in the form of culture liquid on the destruction of oil in water (3.0-6.0 g/L) and soil (20 g/kg), including in the presence of Cd2+ and Pb2+ (0.01-0.5 mM), was investigated. It was shown that the degree of oil degradation in water and soil after 20 days in the presence of low concentrations of Cu2+ (0.01-0.05 mM) and culture liquid of strains IMV B-7241, IMV Ac-5017, and IMV B-7405 was 15 - 25% higher than without copper cations. The activating effect of Cu2+ on the decomposition of complex oil and Cd2+ and Pb2+ pollution was established: after treatment with surfactant of A. calcoacelicus IMV B-7241 and R. erythropolis IMV Ac-5017 destruction of oil in water and soil was 85-95%, and after removal of the copper cations decreased to 45-70%. Intensification of oil destruction in the presence of copper cations may be due to their stimulating effect on the activity of alkane hydroxylases as in surfactant-producing strains, and natural (autochthonous) oxidizing microbiota.

[Influence of heavy metals on surfactants synthesis by Nocardia vaccinii IMV B-7405].

The production of surfactants by Nocardia vaccinii IMV B-7405 in glycerol -and hydrocarbon-containing medium after addition Cd(3+) Pb(2+) and Cu(2+) was investigated. It was established that the introduction of 0.1 mM Cu(2+) in the exponential growth phase of IMV B-7405 strain or simultaneous addition of Cu(2+) (0.1 mM) and Cd(2+) (0.3 mM), Cu(2+) (0.1 mM) and Pb(2+) (0.3 mM) in stationary phase was accompanied by the increase of conditional concentration of the surfactant (by 53 and 20-26%, respectively) compared with indexes in the medium without metals cations. It was established that the surfactants of N. vaccinii IMV B-7405 possessed protective functions from heavy metals influence. After surfactants elimination the survival of cells of strain IMV B-7405 in the presence of Cu(2+) (1.5-2.5 mM), Cd(2+) or Pb(2+) (0.1-0.3 mM) decreased a few times (to 5-45%). The inhibition action of Cu(2+) on alkane hydroxylase activity (the first enzyme of hydrocarbon catabolism) and stimulation--on phosphoenolpyruvate synthetase (enzyme of surface-active glycolipids biosynthesis) in MB B-7405 have been established.

[Antiadhesive potencial of Rhodococcus erythropolis IMB Ac-5017 biosurfactants].

The effect of Rhodococcus erythropolis IMB Ac-5017 biosurfactants (surface-active substances, SAS) with different degree of purification on attachment of bacteria (Escherichia coli IEM-1, Bacillus subtilis BT-2, Proteus vulgaris BT-1, Staphylococcus aureus BMC-1, Pseudomonas aeruginosa P-55, Enterobacter cloacae AC-22, Erwinia aroidaeae B-433), yeasts (Candida albicans D-6) and fungi (Aspergillus niger P-3, Fusarium culmorum T-7) to the abiotic surfaces (glass, plastic, ceramics, steel, linoleum) was studied. The dependence of microorganisms adhesion on degree of SAS purification (supernatant, purified SAS solution), SAS concentration (0,04-1,25 mg/ml), type of surface and test-cultures was established. The adhesion of majority investigated bacterial cells after treatment of abiotic surfaces with supernatant of cultural liquid with SAS concentration 0,06-0,25 mg/ml was on the average 20-45, yeasts C. albicans D-6--30-75% and was less than that purified SAS solution with the same concentration. Higher antiadhesive activity of supernatant as compared to purified SAS solution testifies to possibility of exception of the expensive stage of isolation and purification at obtaining of preparations with antiadhesive properties.

[Antiadhesive properties of the surfactants of Acinetobacter calcoaceticus IMB B-7241, Rhodococcus erythropolis IMB Ac-5017, and Nocardia vaccinii IMB B-7405].

Attachment of the cells of some bacteria, yeasts, and micromycetes to various surfaces (catheters, dentures, plastic, polyvinyl chloride, tiles, and steel) treated with the surfactants fromAcinetobacter calcoace- ticus IMB B-7241, Rhodococcus erythropolis IMB Ac-5017, and Nocardia vaccinii IMB B-7405 was studied. Adhesion of microorganisms to all the studied surfaces depended on the surfactant concentration and purity, kind of surface, and the test culture. Treatment with the surfactants from N. vaccinii IMB B-7405 (0.005- 0.05 mg/mL), A. calcoaceticus IMB B-7241 (0.003-0.036 mg/mL), and R. erythropolis IMB Ac-5017 (0.03- 0.12 mg/mL) resulted in adhesion decreased respectively by 35-75, 60-75, and 25-90% for bacteria (Es- cherichia coli IEM-1, Bacillus subtilis BT-2, etc.), by 80-85, 55-90, and 15-60% for yeasts Candida albicans D-6, and by 40-50, 35-45, and 10-20% for micromycetes (Aspergillus niger P-3 and Fusarium culmorum T-7).

[Influence of pH on synthesis of Acinetobacter calcoaceticus IMV B-7241 biosurfactants].

Synthesis of extracellular metabolites with surface-active and emulsifying properties, pH being maintained at the level of 5.8-8.0, in the process of cultivation of Acinetobacter calcoaceticus IMV B-7241 in the medium with ethanol (2%, volume part) was investigated. It is established that the neutral value of pH is optimal for synthesis of surface-active substances (SAS, biosurfactants) of A. calcoaceticus IMV B-7241. The maintenance of pH at the level of 7.0 with the help of KOH solution was accompanied by the 1.8-fold increase of the amount of synthesized SAS as compared with the process indicators without regulation of pH. The substitution of KOH by NaOH to maintain pH at the optimal level led to the 1.2-1.5-fold decrease of SAS concentration that is determined by the inhibiting effect of sodium cations on activity of biosynthesis enzymes of surface-active amino- and glycolipids of A. calcoaceticus IMV B-7241. The medium neutralization by KOH solution in the process of cultivation of the strain IMV B-7241 with further introduction of fumarate (0.01%) and citrate (0.01%) at the end of the exponential phase was accompanied by the 1.2-fold increase of the amount of synthesized SAS compared with the indicators of the analogous process without neutralization and by the 3 5-fold increase compared with bacteria cultivation on ethanol without organic acids and pH regulation.

[Effect of Cu2+ on synthesis of biosurfactants of Acinetobacter calcoaceticus IMV B-7241 and Rhodococcus erythropolis IMV Ac-5017].

Synthesis of biosurfactants (surface-active substances, SAS) was investigated under the conditions of growth of Rhodococcus erythropolis IMV Ac-5017 and Acinetobacter calcoaceticus IMV B-7241 on hydrophobic (n-hexadecane, liquid paraffins, sunflower oil) and hydrophilic (ethanol) substrates depending on concentration (0.01-0.5 mM) and time of copper cations introduction in the medium. It is established that Cu2+ addition in the exponential phase of growth of the strains IMV B-7241 and IMV Ac-5017 on all studied substrates was accompanied by the increase of conventional concentration of SAS by 25-140% as compared with the indices in the medium without copper cations. Maximum synthesis intensification of SAS of A. calcoaceticus IMV B-7241 and R. erythropolis IMV Ac-5017 was observed in the case of Cu2+ introduction in the medium with hydrocarbons. The increase of SAS synthesis in the presence of copper cations is determined by their activating effect on activity of alkane hydroxylase of the both strains, as well as 4-nitroso-N,N-dimethylaniline-dependent alcohol dehydrogenase and enzymes of biosynthesis of surface active glyco-(phosphoenolpyruvate-synthetase) and aminolipids (NADP(+)-dependent glutamate dehydrogenase) in A. calcoaceticus IMV B-7241.

[Effect of surface-active substances of Acinetobacter calcoaceticus IMV B-7241, Rhodococcus erythropolis IMV Ac-5017, and Nocardia vaccinii K-8 on phytopathogenic bacteria].

The effect of surface-active substances (SAS's) of Acinetobacter calcoaceticus IMV B-7241, Rhodococcus erythropolis IMV Ac-5017, and Nocardia vaccinii K-8 on phytopathogenic bacteria has been studied. It was shown that the survival of cells (10(5)-10(7) in a milliliter) of the Pseudomonas and Xanthomonas phytopathogenic bacteria was found to be 0-33% after treatment with SAS preparations of the IMV Ac-5017 and IMV B-7241 strains for 2 h (0.15-0.4 mg/mL). In the presence of N. vaccinii K-8 SAS preparations (0.085-0.85 mg/mL), the number of cells of the majority of the studied phytopathogenic bacteria decreased by 95-100%. These data show prospects for using microbial SAS's for the construction of ecologically friendly drugs for regulating the number of phytopathogenic bacteria.

[Synthesis of surfactants acinetobacter calcoaceticus IMV B-7241 and Rhodococcus erythropolis IMV Ac-5070 in the medium with glycerol].

It was established that glycerol, a byproduct of biodiesel production, may be used as substrate for synthesis of surfactants Rhodococcus erythropolis IMV Ac-5017 and Acinetobacter calcoaceticus IMV B-7241. Maximum indices of surfactants synthesis by the strain IMV B-7241 have been fixed, when the medium with glycerol included yeast autolysate and trace elements. It was shown that the surfactants synthesis could be intensified when cultivating A. calcoaceticus IMV B-7241 and R. erythropolis IMV Ac-5017 on the mixture of hexadecane and glycerol in concentration of 0.5-1.0% (in volume). When using inoculate grown on hexadecane, the conditional concentration of the surfactant A.calcoaceticus IMV B-7241 on the mixed substrate was higher by 56-100, and that of R. erythropolis IMVAc-5017 by 260-320 % than on the monosubstrate glycerol. The paper is presented in Russian.

[Production of surfactants by Acinetobacter calcoaceticus K-4 grown on ethanol with organic acids].

The effect of fumarate (C4-dicarboxylic acid, a gluconeogenesis precursor) and citrate (a lipid synthesis regulator) on the production of surfactants by Acinetobacter calcoaceticus K-4 grown on ethanol has been studied. Simultaneous addition of fumarate and citrate to concentrations of 0.01-0.02% at the end of the log phase of K-4 growth in a medium with 2 vol% ethanol increases the nominal surfactant concentration by 45-55% in comparison with a culture without organic acids. The increased level of surfactant production in the presence of fumarate and citrate is determined by the increase in the activities of enzymes involved in the production of glycolipids (phosphoenolpyruvate synthase and trehalose phosphate synthase) and aminolipids (NADP(+)-dependent glutamate dehydrogenase) by factors of 1.7-7, as well as by the simultaneous operation of two anaplerotic pathways: the glyoxylate cycle and the reaction catalyzed by phosphoenolpyruvate carboxylase.

[Effect of biosurfactants Acinetobacter calcoaceticus K-4 and Rhodococcus erythropolis EK-1 on some microorganisms].

It has been established that the preparations of biosurfactants Rhodococcus erythropolis EK-1 (0.61 -2.1 mg/ml) and Acinetobacter calcoaceticus K-4 (0.15 - 0.22 mg/ml) in a form of supernatants of the cultural liquid show antimicrobial effect in respect of a number of microorganisms (Bacillus subtilis BT-2, Escherichia coli IEM-1, Candida tropicalis BT-5, Candida albicans D6, Candida utilis BVC-65, Saccharomyces cerevisiae OB-3). No inhibiting effect of biosurfactant preparations of R. erythropolis EK-1 on the cells of S. cerevisiae OB-3 and E. coli IEM-I and antifungal effect of the both studied surfactants on Aspergillus niger P-3 and Fusarium culmorum T-7 were revealed. The survival of microbe cells depend on biosurfactants concentration in the preparations, on exposure time as well as on physiological state of test-cultures. It has been established that the surfactant preparations of A. calcoaceticus K-4 had a higher effect on the spores of B. subtilis BT-2, than on vegetative cells, thus decreasing the spore culture survival by 75% in 2 h of exposure.

[Influence of metal nanoparticles on some microorganisms and microflora of unpasteurized beer].

The influence of nanoparticles of gold, silver, dioxide of cerium and zirconium in low concentration (0.5-7.5 mg/l) on pure cultures of Escherichia coli IEM-1, Bacillus subtilis BT-2, Candida scottii KB-2, Saccharomyces cerevisiae OB-3, Aspergillus niger R-3, Fusarium culmorum T-7 and Penicillium chrysogenum F-7 has been investigated. Silver nanoparticles, which caused a decrease of the amount of S. cerevisiae OB-3 cells by 90% after one hour of exposition, and led to almost complete death of vegetative and spore cells of B. subtilis BT-2 after 1 and 24 h of exposition, respectively, proved to be the most effective antimicrobial preparation. The decrease by one-two orders of the amount of B. subtilis BT-2 and of S cerevisiae OB-3 cells under the influence of preparations of silver nanoparicles in the presence of gold has been established. After adding silver preparations to the unpasteurized beer one could observe a decrease by 10-20% of bacterial and by about 40% of fungi which contaminated microflora on the 20th day of shelf-life. The paper is presented in Ukrainian.