[EFFECT OF Zn²âº ON SYNTHESIS OFACINETOBACTER CALCOACETICUS IMV B-7241 SURFACTANTS WITH ANTIMICROBIAL AND ANTIADHESIVE PROPERTIES].

AIM: To study the effect of zinc cations in the composition of ethanol and n-hexadecane containing medium on the antiadhesive and antimicrobial activity of Acinetobacter calcoaceticus IMV B-7241 surfactants. METHODS: Surfactants were extracted from supernatant of cultural liquid by mixture of chloroform and methanol (2:1). The number of attached cells was determined spectrophotometrically, antimicrobial properties - by index of the minimum inhibitory concentration (MIC). RESULTS: Adding Zn²âº (38 mmol/l) into medium with ethanol and n-hexadecane containing copper sulphate and iron sulphate, was accompanied by the formation of surfactant with higher antimicrobial and antiadhesive activity, as well as increasing activity of NADP⁺-dependent glutamate dehydrogenase - a key enzyme of aminolipids biosynthesis. The minimum inhibitory concentration against Escherichia coli IEM- 1, Enterobacter cloaceae C-8, Staphylococcus aureus EMC- 1 and Proteus vulgaris IIA- 12 of surfactants, synthesized in the presence of Zn²âº, and the adhesion of E. coli IEM-1 on abiotic surfaces treated with such surfactants, were respectively in 1.6-3.3 times and 10-19 % lower than those of the preparations obtained under cultivation of IMV B-7241 strain in medium without zinc cations. The activity of NADP⁺-dependent glutamate dehydrogenase at the end of exponential phase of A. calcoaceticus IMV B-7241 growth in medium with ethanol (n-hexadecane), copper, zinc and iron sulfate; was 1739±87 (8333±416) nmol-min⁻¹ mg⁻¹ protein that in 2 and 15 times higher than under the same conditions cultivation on ethanol and n-hexadecane without Zn²âº. CONCLUSIONS: The obtained data suggest the possibility of biosynthesis regulation of A. calcoaceticus IMV B-7241 surfactants with antimicrobial and antiadhesive properties, when zinc cations (activator NADP⁺-dependent glutamate dehydrogenase - a key enzyme of aminolipids synthesis) were added into medium with ethanol (n-hexadecane), as well as the possibility of regulating the biological properties of the surfactants during cultivation of producer.

[Biological Properties of Nocardia vaccinii IMV B-7405 Surfactants Synthesized on Fried Sunflower Oil].

Aim: To study of antimicrobial and antiadhesive properties of the surface-active substances (surfactants) Nocardia vaccinii IMV B-7405 synthesized on different oil-containing substrates (refined and waste after frying meat and potatoes sunflower oil). Methods: Surfactants were extracted from supernatant of cultural liquid by mixture of chloroform and methanol (2 : 1). Antimicrobial against bacteria and yeast properties of the surfactant was determined by index of the minimum inhibitory concentration (MIC). The number (%) of attached cells (adhesion) was determined as a ratio of the optical density of the suspension obtained from the materials treated with surfactants to the optical density of the control samples (100 %). Results: It was established that surfactants synthesized N. vaccinii IMV B-7405 on fried oil, at a concentration of 0.02 - 0.04 mg/ml decreased adhesion of bacteria (Escherichia coli IEM-1, Bacillus subtilis BT-2) on plastic, dutch tile, glass and linoleum by 25-90 %, and yeast Candida albicans Д-6 - by 15 - 65 %. The minimum inhibitory concentration with respect to studied test cultures surfactants synthesized on waste after frying potato oil was 8 - 67 mg/ml, and against phytopathogenic bacteria Pectobacterium carotovorum UCM B-1095, Pseudomonas syringae pv. atrofaciens UCM B-1015 and Xanthomonas campestris pv. campestris UCM B-1049 - 14 - 52 mg/ml. Conclusions: Replacing traditional substrates on fried oil can not only reduce cost of N. vaccinii IMV B-7405 surfactant biosynthesis, but also to obtain the final product with high antiadhesive and antimicrobial properties. The dependence of antiadhesive and antimicrobial potential of surfactants on the nature of the carbon source indicate the need for studies effect of cultivation conditions of producer on biological properties of synthesized surfactants.

[Antimicrobial Properties Surfactants Synthesized under Different Cultivation Conditions of Acinetobacter calcoaceticus EMV B-7241].

Aim: To study the antimicrobial properties of the surface-active agents (surfactants) Acinetobacter calcoaceticus IMV B-7241 depending on the availability of yeast autolysate and trace elements in the composition of ethanol-, n-hexadecane- and glycerol-containing media. Methods: Antimicrobial against bacteria (Escherichia coli IEM-1, Bacillus subtilis BT-2), and yeast (Candida albicans D-6) properties of the surfactant was determined by index of the minimum inhibitory concentration (MIC). Surfactants were extracted from supernatant of cultural liquid by mixture of chloroform and methanol (2:1). Results: The removal from cultivation medium yeast autolysate and trace element mix and replacing them by copper sulfate and iron sulphate in the medium with ethanol and n-hexadecane, and in the medium with glycerol - by potassium chloride, zinc sulfate and copper sulfate accompanied by decreasing antimicrobial properties of surfactants. The most effective antimicrobial agents were surfactant synthesized on ethanol in the presence of yeast autolysate and trace elements (MIC 9-20 µ/ml), whereas the surfactant obtained under similar cultivation conditions on glycerol and n-hexadecane, inhibited growth of tested bacteria and yeast at higher (9-68 and 27-54 µ/ml, respectively) concentrations. The minimum inhibitory concentration of surfactant, synthesized in a medium with ethanol (glycerol, n-hexadecane), yeast autolysate and trace elements, correlated with the activity of NADP+-dependent glutamate dehydrogenase - a key enzyme of aminolipids biosynthesis (610 ± 30, 395 ± 24, 397 ± 24 nM min-1·mg-1 protein, respectively). Conclusions: The higher activity of NADP+-dependent glutamate dehydrogenase when growing the strain IMV B-7241 in a medium with ethanol (n-hexadecane), yeast autolysates and trace elements compared to that in a medium with copper sulfate and iron sulfate, as well as an increase enzyme activity in the presence of zinc cations suggests the possibility of increasing synthesis aminolipids by introducing Zn2+ in the medium with ethanol and n-hexadecan. The obtained data indicate the need for studies depending on biological properties of surfactants of the cultivation conditions of producer.

[EFFECT OF CULTIVATION CONDITION OF ACINETOBACTER CAL COACETICUS IMV B-7241 ON ANTIADHESIVE PROPERTIES OF SURFACTANTS].

AIM: To study the effect of growth factors and microelements in composition of ethanol-, n-hexadecane- and glycerol-containing media on antiadhesive properties of A cinetobacter calcoaceticus IMV B-7241 surfactants. METHODS: Surfactants were extracted from supernatant of cultural liquid by mixture of chloroform and methanol (2:1). The number (%) of attached cells (adhesion) was determined as a ratio of the optical density of the suspension obtained from the materials treated with surfactants to the optical density of the control samples (100 %). RESULTS: Dependence of surfactants antiadhesive properties on presence in the medium of A. calcoaceticus IMB B-7241 cultivation of growth factors and certain microelements, as well as the nature of the carbon source was established. Adhesion of bacteria (Escherichia coli IEM- 1, Bacillus subtilis BT-2) and yeast (Candida albicans D-6) on plastic, dutch tile, linoleum, and steel was a minimal (25-35 %) after surface treatment with surfactant (0.005 mg/ml) synthesized on ethanol in the presence of yeast autolysate and microelements. Replacement the yeast autolysate and microelement mixture in the composition of ethanol- and n-hexadecane-containing media by copper sulfate and iron sulfate and in the medium with glycerol by KCl, zinc sulfate and copper sulfate accompanied by decreasing antiadhesive properties of synthesized surfactants. CONCLUSIONS: The obtained data indicate that the increasing surfactant synthesis does not always the accompanied by the formation of product with the required biological properties and indicate the need for studies depending on biological properties of surfactants of the cultivation conditions of producer.

[GLUCOSE METABOLISM IN SURFACTANTS PRODUCER NOCARDIA VACCINII IMV B-7405].

Key enzymes of glucose metabolism were detected in the cells of surfactants producer Nocardia vaccinii IMV B-7405 grown on this substrate. It has been established that glucose catabolism is performed through gluconate (FAD(+)-dependent glucose dehydrogenase activity 698 ± 35 nmol x min(-1) x mg(-1) of protein). Oxidation of gluconate to 6-phosphogluconate is catalised by gluconokinase (178 ± 9 nmol x min(-1) x mg(-1) of protein). 6-Phosphogluconate was involved into pentose phosphate cycle by constitutive NADP(+)-dependent 6-phosphogluconate dehydrogenase (activity 357 ± 17 nmol x min(-1) x mg(-1) of protein). The data obtained serve as the basis for theoretical calculations of optimal molar ratio of concentrations of energetically nonequivalent substrates for intensifying the surfactants synthesis on their mixture.

[PECULIARITIES OF GLUCOSE AND GLYCEROL METABOLISM IN Nocardia vaccinii IMB B-7405].

It has been established that in cells of Nocardia vaccinii IMB B-7405 (surfactant producer) glucose catabolism is performed through pentose phosphate cycle as well as through gluconate (activity of NAD+-dependent glucose-6-phosphate dehydrogenase and FAD+-dependent glucose dehydrogenase 835 ± 41 and 698 ± 35 nmol.min-1.mg-1 of protein respectively). 6-Phosphogluconate formed in the gluconokinase reaction is involved in the pentose phosphate cycle (activity of constitutive NADP+-dependent 6-phosphogluconate dehydrogenase 357 ± 17 nmol.min-1.mg-1 of protein). Glycerol catabolism to dihydroxyacetonephosphate (the intermediate of glycolysis) may be performed in two ways: through glycerol-3-phosphate (glycerol kinase activity 244 ± 12 nmol.min-1.mg-1 of protein) and through dihydroxyacetone. Replenishment of the C4-dicarboxylic acids pool in N. vaccinii IMV B-7405 grown on glucose and glycerol occurs in the phosphoenolpyruvate(PEP)carboxylase reaction (714-803 nmol.min-1.mg-1 of protein). 2-Oxoglutarate was involved in tricarboxylic acid cycle by alternate pathway with the participation of 2-oxoglutarate synthase. The observed activity of both key enzymes of gluconeogenesis (PEP-carboxykinase and PEP-synthase), trehalose phosphate synthase and NADP+-dependent glutamate dehydrogenase confirmed the ability of IMV B-7405 strain to the synthesis of surface active glycoand aminolipids, respectively.

[BIOCONVERSION OF CRUDE GLYCEROL AND MOLASSES MIXTURE IN BIOSURFACTANTS OF NOCARDIA VACCINII IMB B-7405].

The possibility of replacing glucose and pure glycerol in mixed substrates for surtace-active substances (SAS, biosurfactants) biosynthesis of Nocardia vaccinii IMB B-7405 on molasses (sugar production waste) and crude glycerol (by-product of biodiesel production) was established. It was established that the increasing concentration of crude glycerol to 6% in mixture with 1.0% molasses was accompanied by increase of amount of SAS synthesized more than twice, and the increasing content of molasses to 3.0% in mixture with 1.0% crude glycerol--by some decrease in the level of surfactant as compared to that in a medium containing 1.0% monosubstrates. It was shown that the increasing concentration of sodium nitrate to 2-fold in medium cultivation of N. vaccinii IMB B-7405 allowed to increase to 7.0% content of grude glycerol in mixture with 1.0% molasses. Under such conditions of cultivation concentration of exocellular SAS synthesized was 7,5 g/l, that to 1,3 fold higher than in basic medium with a lower content of nitrogen source.

[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.

[ANTIMICROBIAL ACTION OF NOCARDIA VACCINII IMV B-7405 SURFACTANTS].

AIM: To study the effect of Nocardia vaccinii IMV B-7405 surfactants on some bacteria (including pathogens of genera Proteus, Staphylococcus, Enterobacter), yeast of Candida species and fungi (Aspergillus niger R-3, Fusarium culmorum T-7). METHODS: The antimi- crobial properties of surfactant were determined in suspension culture by Koch method and also by index of the minimum inhibitory concentration. Surfactants were extracted from supernatant of cultural liquid by mixture of chloroform and methanol (2:1). RESULTS: It is shown that the antimicrobial properties of N. vaccinii IMV B-7405 surfactant depended on the degree of purification (supernatant, solution of surfactant), concentration and exposure. Survival of Escherichia coli IEM-1 and Bacillus subtilis BT-2 (both vegetative cells and spores) after treatment for 1-2 hours with surfactants solution and the supernatant (the surfactant concentration 21 µg/ml) was 3-28%. Minimum inhibitory concentrations of N. vaccinii IMV B-7405 surfactants on studied bacteria, yeast and micromycetes were 11.5-85.0; 11.5-22.5 and 165.0-325.0 µ/ml respectively. CONCLUSIONS: Minimum inhibitory concentrations of N. vaccinii IMV B-7405 surfactants are comparable to those of the known microbial surfactants. The possibility of using the supernatant of culture liquid as an effective antimicrobial agent noticeably simplifies and reduces the cost of the technology of its obtaining.

[SYNTHESIS OF PHYTOHORMONES BY NOCARDIA VACCINII IMV B-7405--PRODUCER OF SURFACTANTS].

AIM: To study the synthesis of phytohormones (auxins, cytokinins, abscisic acid) under cultivation of Nocardia vaccinii IMV B-7405 (surfactants producer) in media containing different carbon sources (glycerol, refined sunflower oil, as well as waste oil after frying potatoes and meat). METHODS: Phytohormones were extracted from supernatants of culture liquid (before or after surfactant separation) by ethylacetate (auxins, abscisic acid) and n-butanol (cytokinins), concentrated and purified by thin-layer chromatography, then quantitative determination was performed using a scanning Sorbfil spectrodensitometer. RESULTS: While growing in medium with refined oil IMV B-7405 strain synthesized 1.8 ± 0.09 g/l extracellular surfactant, also maximum amount of auxins (245-770 µ/l) and cytokinins (134-348 µl). Cultivation of N. vaccini LMV B-7405 on waste oil was accompanied by decreasing amount of phytohormones to 23-84 µ/l (auxins) and 16-90 µ/l (cytokinins) and increasing surfactant concentration to 2.3-2.6 g/l. The level of abscisic acid synthesis was practically not dependent on the nature of growth substrate, was substantially lower than that of auxins and cytokinins and ranged from 2 to 12 µ/l. CONCLUSIONS: Obtained data demonstrate the possibility of using oil-containing industrial waste for the simultaneous synthesis of both surfactants and phytohormones, and indicate the need for studies of the effect of producer cultivation conditions on the biological properties of the target products of microbial synthesis.

[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.

[Synthesis of surfactants by Rhodococcus erythropolis IMV Ac-5017, Acinetobacter calcoaceticus IMV B-7241 and Nocardia vaccinii IMV B-7405 on industrial waste].

The synthesis of surfactants by Rhodococcus erythropolis IMV Ac-5017, Acinetobacter calcoaceticus IMV B-7241 and Nocardia vaccinii IMV B-7405 on industrial waste (food and oil-processing industry, production of biodiesel) was investigated. The possibility of replacing the expensive substrates (n-hexadecane and ethanol) by industrial waste (oil and fat industry, fried sunflower oil, glycerol, liquid paraffin) for the surfactant biosynthesis was established. The conditional concentration of surfactants was maximal on oil containing substrates and exceeded those on n-hexadecane and ethanol 2-3 times. The highest rates of surfactants synthesis were observed on fried sunflower oil with the use of inoculum grown on carbohydrate substrates (glucose, molasses). It was established that the addition of glucose (0.1%) was accompanied by 2-4-fold intensification of surfactants synthesis by R. erythropolis IMV Ac-5017 and N. vaccinii IMV B-7405 on fried sunflower oil (2%).

[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.

[Intensification of surfactants synthesis by Nocardia vaccinii K-8 on crude glycerol].

The authors studied the effect of components of crude glycerol (potassium and sodium salts, ethanol, methanol) - the by-products of biodiesel production on formation of surfactants (surface-active substances, SAS) by Nocardia vaccinii K-8, as well as possibility to intensify the SAS synthesis by the strain K-8 on crude glycerol in the presence ofbiosynthesis precursors (glucose, sun-flower oil, organic substances). It has been established that the introduction of potassium (sodium) chloride in concentration 2.5 % and ethanol (methanol) in concentration 0.3 % into the medium with refined glycerol (1 %) was accompanied by the 14-1.7-fold increase of conditional SAS concentration as compared with indices on the medium without adding salts and alcohols. Under cultivation conditions of strain K-8 on the medium with crude glycerol the conditional SAS concentration was 3-fold higher than on the medium with refined substrate. Introduction of glucose (0.05 %), sun-flower oil (0.05 %), fumarate and citrate (0.1 %) during the stationary growth phase of N. vaccinii K-8 into the medium with crude glycerol (2.2%) was accompanied by the increase in the amount of synthesized SAS h by 17-44 % compared with cultivation of bacteria on the medium without precursors.

[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 univalent cations on synthesis of surfactants by Acinetobacter calcoaceticus IMV B-7241].

The effect of univalent cations on activity of key enzymes of C2-metabolism has been investigated in the producer of biosurfactants, Acinetibacter calcoaceticus IMV B-7241 grown on ethanol. It was established that potassium cations are inhibitors of pyroquinolinequinone-dependent alcohol- and acetaldehyde dehydrogenases, the enzymes of biosynthesis of surface-active aminolipids (NADP-dependent glutamate dehydrogenase) and glycolipids (phosphoenopyruvate (PhEP)-carboxikinase), while ammonium cations are activators of these enzymes and PhEP-carboxylase. A decrease of potassium cations concentration in the cultivation medium to 1 mM and increase of the content of amine nitrogen to 10 mM as a result of potassium nitrate substitution by equimolar, as to nitrogen, urea concentration were accompanied by the increase of activity of enzymes of ethanol metabolism and SAS biosynthesis, as well as by the 2-fold increase of conditional concentration of the biosurfactants.

[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 growth factors and some microelements on biosurfactant synthesis of Acinetobacter calcoaceticus IMV B-7241].

The effect of yeast autolysate and microelements on synthesis of surface-active substances (SAS, biosurfactants) was investigated under cultivation of Acinetobacter calcoaceticus IMV B-7241 on various carbon substrates (n-hexadecane, ethanol, glycerol). The authors have shown a possibility to substitute the yeast autolysate and microelement mixture in the composition of ethanol- and n-hexadecane-containing media by copper sulfate (0.16 micromol/l) and iron sulfate (3.6 micromol/l), and in the medium with glycerol by 0.21 mmol/l of KCl, 38 micromol/l of zinc sulfate and 0.16 micromol/l of copper sulfate. Under such conditions of cultivation of the strain IMV B-7241 the SAS concentration exceeded that on the initial media, which contained the yeast autolysate and microelements, 1.2-1.6 times. The authors have also established the activating effect of low (0.01 mM) concentrations of Fe2+ on activity of the enzymes of biosynthesis of surface-active amino- (NADP-dependent glutamate dehydrogenase) and glycolipids (phosphoenolpyruvate(PhEP)-synthetase, PhEP-carboxykinase), as well as of anaplerotic reaction(PhEP-carboxylase). A necessity to introduce zinc cations into glycerol-containing medium is determined by their stimulating effect on activity of 4-dinitroso-N,N-dimethylaniline-dependent alcohol dehydrogenase--one of the enzymes of this substrate catabolism in A. calcoaceticus IMV B-7241.

[Glycerol metabolism in surfactants producers Acinetobacter calcaaceticus IMV B-7241 and Rhodococcus erythropolis IMV Ac-5017].

Key enzymes of glycerol metabolism were detected in the cells of surfactants producers Rhodococcus erythropolis IMV Ac-5017 and Acinetobacter calcaaceticus IMV B-7241 grown on glycerol. It has been established that in the both strains glycerol catabolism to dihydroxyacetonephosphate (the intermediate of glycolysis) may be performed in two ways: through glycerol-3-phosphate (glycerol kinase activity 740-840 nmol min(-1) mg(-1) of protein) and through dihydroxyacetone. Glycerol oxidation to dihydroxyacetone in the strains IMV B-7241 and Ac-5017 is catalised by pyrrholo-quinolinquinone-dependent glycerol dehydrogenases and nitroso-N,N-dimethylaniline-dependent alcohol dehydrogenases. Both glyoxylate cycle and phosphoenol pyruvate(PEP)-carboxylase function as anaplerotic paths in R. erythropolis IMV Ac-5017, and only PEP-carboxylase reaction (1045 +/- 52 nmol min(-1) mg(-1) of proteins) functions in A. calcoaceticus IMV B-7241. The data obtained serve as the basis for theoretical calculations of optimal molar ratio of concentrations of energetically nonequivalent substrates for intensifying the surfactants synthesis on their mixture.