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Co-Mo/γ-Al2O3 catalysts with different pore shapes were synthesized for the ex situ upgrading of extra heavy oils by hydrodesulfurization (HDS), hydrodemetallization (HDM), and hydrodeasphaltization (HDA). The catalysts were synthesized using aluminum oxides that were prepared by various methods. It was found that using the product obtained by the thermochemical activation of gibbsite leads to the formation of slit-shaped pores in aluminum oxide, while the application of the hydroxide deposition method by the precipitation of sodium aluminate and nitric acid gives cylindrical pores in aluminum oxide. Co-Mo catalysts synthesized using these two types of pores exhibit different catalytic activities. The catalyst synthesized on a carrier with cylindrical pores exhibited a higher catalytic activity in sulfur, heavy metals, and asphaltenes removal reactions that are synthesized on a carrier with slit-like pores. This is because the presence of cylindrical pores leads to a decrease in diffusion restrictions when removing large molecules of asphaltenes and sulfur-containing and metal-containing compounds.

Alumina-supported palladium catalysts with acetate and acetylacetonate as precursors were synthesized. The properties of palladium in these systems treated in oxidizing and reducing atmospheres in a wide temperature range of 300–700 °C were investigated. According to the results of UV-vis DRS and TPR, the Pd(Ac)2/(δ + ϰ)-Al2O3 systems, oxidized at 300–700 °C, are characterized by the presence of large particles of PdO and Pd2+ in the structure of the aluminate phases. The subsequent reduction at 500 °C of the preoxidized Pd(Ac)2/(δ + ϰ)-Al2O3 systems according to the TEM results is accompanied by the formation of well crystallized palladium particles with an average diameter of 1.2 nm, which are characterized by the presence of the hydride form of hydrogen. The oxidation of Pd(Acac)2/(δ + ϰ)-Al2O3 in the temperature range 300–700 °C leads to the formation of small clusters of PdO and palladium–aluminate phases. When reducing, only cluster forms of palladium with a diameter of 1.3 nm are formed from them. It should be noted that palladium particles of catalysts have a close charge state and properties of active centers according to XPS and IRS of adsorbed CO. Therefore, the higher activity of the Pd(Ac)2/(δ + ϰ)-Al2O3 system is due to the presence of the hydride form of hydrogen. This fact leads to a high conversion of methylacetylene and propadiene, but a low selectivity of their conversion to propylene. An increase in the temperature of treatments to 600 °C is accompanied by an increase in the particle size of palladium. According to the results of IR spectroscopy of adsorbed carbon monoxide for the systems Pd(Ac)2/(δ + ϰ)-Al2O3 and Pd(Acac)2/(δ + ϰ)-Al2O3, the number of Pdδ+ centers and groups consisting of three atoms Pd0 is noted. This probably leads to the formation of fewer unsaturated hydrocarbon molecules firmly bound to the surface of the palladium particles, and less screening of the active surface of the palladium particles, with the formation of large areas of active sites where chemisorption of methylacetylene and propadiene is sterically possible. This in turn leads to an increase in the conversion of acetylene and diene hydrocarbons.

Two charge-transfer bicomponent 1:1 crystals of polycyclic aromatic hydrocarbons (anthracene and tetracene) with a new acceptor molecule (perfluoroanthraquinone) were grown by slow evaporation from...

The transformation of alumina-supported palladium salts during isothermal treatment in a reducing atmosphere has been studied to determine the optimum reduction temperature for the Pd/Al2O3 catalyst. It has been found that the interaction of palladium acetylacetonate with alumina surface sites is stronger than the interaction of the acetate complex. Owing to this factor, the diameter of the resulting active-ingredient particles is smaller in the case of the former precursor in the entire temperature range of reductive treatments. The optimum reduction temperature for the supported palladium salts is 500°С; this temperature provides the formation of palladium particles characterized by the maximum conversion of methylacetylene and propadiene at a high selectivity for conversion to propylene. The systems activated at temperatures of up to 400°C exhibit low activity in the hydrogenation of methylacetylene and propadiene; this behavior is attributed to an incomplete reduction of palladium from Pd salts to form oxidized and coordinatively unsaturated species of the active ingredient.

The present work introduces both synthesis of silica nanoparticles doped with CoII ions by means of differently modified microemulsion water-in-oil (w/o) and St&ouml, ber techniques and characterization of the hybrid nanoparticles (CoII@SiO2) by TEM, DLS, XRD, ICP-EOS, SAXS, UV-Vis, and UV-Vis/DR spectroscopy and electrochemical methods. The results reveal the lack of nanocrystalline dopants inside the hybrid nanoparticles, as well as no ligands, when CoII ions are added to the synthetic mixtures as CoII(bpy)3 complexes, thus pointing to coordination of CoII ions with Si-O- groups as main driving force of the doping. The UV-Vis/DR spectra of CoII@SiO2 in the range of d-d transitions indicate that St&ouml, ber synthesis in greater extent than the w/o one stabilizes tetrahedral CoII ions versus the octahedral ions. Both cobalt content and homogeneity of the CoII distribution within CoII@SiO2 are greatly influenced by the synthetic technique. The electrochemical behavior of CoII@SiO2 is manifested by one oxidation and two reduction steps, which provide the basis for electrochemical response on glyphosate and HP(O)(OEt)2 with the LOD = 0.1 &mu, M and the linearity within 0.1&ndash, 80 &mu, M. The St&ouml, ber CoII@SiO2 are able to discriminate glyphosate from HP(O)(OEt)2, while the w/o nanoparticles are more efficient but nonselective sensors on the toxicants.

Highly porous cellular material (&alpha, Al2O3-HPCM) support was synthesized by the template method. Highly porous support was used for the synthesis of the catalyst. A thin secondary layer with 25&ndash, 30 &mu, thick &gamma, Al2O3 and zeolite Y was applied on the &alpha, Al2O3-HPCM surface ((&gamma, Al2O3 (85%)-zeolite Y (15%))/&alpha, Al2O3-HPCM). The catalyst based on the highly porous support was tested in a process of decreasing oil viscosity. The catalyst in the form of cylindrical granules and a thermal process of decreasing oil viscosity without the catalyst were used as the basis for comparison. &alpha, Al2O3-HPCM in the catalyst provides low-quantity pores (d &lt, 10 nm) and a quantity of general acid centers compared with the granular catalyst. On the other hand, it shows a more significant oil viscosity decrease (from 2500 to 41 cPs) and a low rate of gas generation (137 mL/h) for the catalyst with highly porous support. A high oil fraction was observed in the presence of the (&gamma, Al2O3-zeolite Y)/&alpha, Al2O3-HPCM compared to the granular catalyst. The presence of large transport cells (pores) 1500&ndash, 2000 &mu, for the catalyst based on highly porous support allowed a work period four times longer than that of experiment only with temperature without catalysts.

For the development of a composite of nickel highly porous permeable cellular material with an applied secondary layer of alumina, transformation of the surface of the highly porous permeable cellular material is investigated at the stages of electrochemical synthesis and stages of alumina application on its surface. Etching of foamed-polyurethane bondings with 20% potassium hydroxide solution is accompanied by destruction of their surface and the formation of defective areas in the form of hillocks, hollows, and other imperfections acting as tin-hydroxide crystallization nuclei. Application of tin chloride with its subsequent hydrolysis leads to the formation of hemispherical tin-hydroxide grains with a mean size of about 80 nm uniformly distributed over the surface. The optimum values of temperature (50°C), solution pH (9–10), and electroless-nickel-plating duration (20–30 min), providing the formation of a conductive sublayer of chemically reduced nickel, are established. Nickel electroplating for 30 to 35 h at a current density of 0.1 A/dm2 yields high uniformity of a metal coating of foamed-polyurethane bondings across the thickness both in the bulk and at the outer periphery of a sample of 30 μm. A composite of nickel highly porous permeable cellular material with an applied alumina secondary layer is synthesized. The latter shows a high degree of uniformity and uniform thickness over the whole surface of bondings of the obtained composite.

Recently new flexible and hydrolytically stable metal-organic framework [M(H2O)2(Fc(PHOO)2)·2H2O]n, M = Co has been synthesized by the use of synthetic technique, described earlier for M = Mn [ 1 ]. The heating of both complexes leads to elimination of water molecules and in the case of Co complex is accompanied by change of its color from orange to dark blue. The corresponding structural changes are reversible and are reflected in vibrational and electronic absorption spectra. Analysis of IR, Raman and UV–vis spectra of complexes shows the same structures of Mn and Co complexes before and after heating and suggests that both Mn and Co coordination polyhedra undergo reversible changes under heating from octahedral to tetrahedral form with ferrocene part remaining unchanged.

Geological samples of calcium carbonates (CaCO3) were investigated by 3He NMR, nitrogen porosimetry, X-ray diffraction and electron microscopy methods. The integral porosity of the samples was obtained by 3He nuclear magnetic resonance method and compared with nitrogen adsorption isotherms data. The advantages of 3He porometry method are discussed.

Influence exerted by acid-base modifiers of aluminum hydroxide on the texture and acid characteristics of the aluminum oxide support was studied. The effect of the modified aluminum oxides on the charge state of the active component of aluminum-palladium catalysts was determined. It was found that catalysts based on a support with high concentration of strong acid centers are characterized by low conversion of butadiene-1,3 due to the firm chemisorption of the diene on electron-deficient palladium particles. Their formation is due to the strong metal-support interaction. By contrast, catalysts synthesized with supports having a small number of acid centers provide a high conversion of butadiene-1,3.

A new redox active coordination polymer [Co(H2O)2(Fc(PHOO)2)·2H2O]n (Fc = ferrocene) was synthesized by the diffusion method and characterized by single-crystal X-ray diffraction. Phosphinate fragments formed infinite chains connected through ferrocene fragments to 2D PCP associated with cobalt atoms. Additional strong hydrogen bonding via the participation of coordinated and lattice water molecules resulted in the formation of a 3D network. The polymer exhibited water-induced crystal-to-amorphous transformation with chromotropism, as confirmed by spectroscopic techniques, elemental analysis, TGA and XRPD. The explosion of the amorphous phase [Co(Fc(PHOO)2)]n to form water vapor readily led to its conversion into the initial crystalline [Co(H2O)2(Fc(PHOO)2)·2H2O]n with a reverse change of color. The dehydrated form of the polymer selectively sorbed water and could be used as a material with the function of an express dehydrator. Moreover, a modified electrode could qualitatively determine the water content in the solvent at a concentration of 0.05%. Both hydrated and dehydrated forms were evaluated as electrode materials for supercapacitors. The [Co(Fc(PHOO)2)]n (dehydrated form) electrode exhibited high specific capacitance and excellent cycling stability. Its maximum specific capacitance was 2517 F g−1 at a current density of 2 A g−1, and the specific capacitance retention was about 90.1% after 1000 cycles.

The demand for C3-C5 olefins is constantly growing, that is why it is important to improve the performance of catalysts for dehydrogenation of light alkanes. The study regards the influence of the supports porous system, the contribution of α-Cr2O3 particles to the state of the active phase and the catalytic performance of the chromia-alumina catalysts in the isobutane dehydrogenation reaction. The catalysts were synthesized by impregnating the support with chromic acid. The supports and the catalysts were studied by the following techniques: low-temperature nitrogen adsorption, temperature-programmed desorption and reduction; UV-Vis- and Raman-spectroscopy, X-ray phase and X-ray fluorescence analyses. It was found that crystals of α-Cr2O3 are formed on a support with 56 m2/g specific surface area and 7.1% (m/m) chromium content, that contributes to stabilization of the particles of highly active phases of amorphous Cr2O3 and polychromates and catalytic performance. Meanwhile, no α-Cr2O3 particles are formed on a support with a 103 m2/g specific surface area and 7.4% (m/m) chromium content. Therefore, in the course of 54 regeneration reactions cycles, the rates of isobutylene formation and isobutylene selectivity are significantly reduced due to agglomeration of amorphous Cr2O3 particles, formation of di-, tri- chromates, and migration of part of chromium into the support structure.

KGS-3 catalyst is tested in the selective hydrogenation of methylacetylene and propadiene contained in industrial pyrolysis propane-propylene fractions at a pilot installation in two successive adiabatic flow reactors equipped with immobile catalyst beds. The optimum technological conditions for hydrogenation are determined, ensuring a residual content of acetylene and diene admixtures of no more than 5 ppm: pressure in the system, 18 atm; hydrocarbon feedstock hourly space velocity (HSV), 2100 h−1; molar ratio of hydrogen to the sum of methylacetylene and propadiene in the first and second reactors, respectively, 1.1 : 1.0 and 1.6 : 1.0; temperatures, 50 and 55 °C. Under these conditions, KGS-3 catalyst ensures 100% conversion of methylacetylene and propadiene with a propylene selectivity of 76.7%. The expected service life of this catalyst is about 14 months. The catalyst can be used for the purification of hydrocarbon fractions containing up to 5 wt % of acetylene and diene admixtures.

Pilot tests of SGA-2M promoted Pd/Al2O3 catalyst in the selective hydrogenation of acetylene are performed on an industrial ethane-ethylene fraction in a system of two serially arranged adiabatic flow reactors. The optimum process conditions under which the conversion of acetylene reaches 100% at a selectivity of 68.2% with respect to ethylene are determined: system pressure, 21 atm; hydrocarbon feedstock hourly space velocity (HSV), 1500 h−1, carbon monoxide concentration, 7 ppm; H2: C2H2 molar ratio at the first and second hydrogenation stages, 1.0: 1.0 and 1.4: 1.0; inlet temperature of the first and second reactors, 40 and 55°C, respectively. The interregeneration service life of the SGA-2M catalyst under optimum conditions is estimated at 12 months. SGA-2M catalysts can be recommended for purifying ethane-ethylene fractions containing up to 2 vol % of acetylene.

The influence of the structural and electronic characteristics of nonpromoted and cobalt-promoted Pd catalysts on their adsorption and catalytic properties is studied. It is shown that the conversion of vinylacetylene depends on the dispersion of palladium for both types of catalysts synthesized from acetate and acetylacetonate complexes. The palladium acetylacetonate catalysts have a higher palladium dispersion than the samples obtained from acetate complex solutions, thus leading to a higher conversion of vinylacetylene. It is established that the selectivity of vinylacetylene conversion into 1,3-butadiene on palladium acetate and acetylacetonate catalysts depends on the state of the 3d orbitals of surface Pd atoms. The palladium acetate catalysts are characterized by a higher electron density on the 3d orbital in comparison with the acetylacetonate samples, thus producing higher selectivities of vinylacetylene conversion into 1,3-butadiene. The introduction of cobalt into Pd/δ-Al2O3 catalyst synthesized from acetylacetonate complex leads to the formation of bimetallic Pd-Co particles, in which Pd atoms have higher electron density than those in the nonpromoted Pd/δ-Al2O3 catalyst, due probably to the donation of electron density from promoter atoms, with a resulting decline in the adsorption ability of bimetallic particles with regard to 1,3-butadiene and hydrogen. As a consequence, the selectivity of vinylacetylene conversion into 1,3-butadiene increases. Requirements for the size, dispersion, and electronic characteristics of the active component in the catalysts for the selective hydrogenation of vinylacetylene are formulated, and two techniques for their synthesis are proposed.

To optimize the chemical composition of catalysts for the selective hydrogenation of diene and vinyl aromatic hydrocarbons in pyrolysis gasoline, we study the effect of the acid-base and textural characteristics of a support modified with additives of sodium compounds on the activity and stability of the catalysts in reactions of hydrogenation and oligomerization of unsaturated compounds. It is shown that the rate of formation of oligomeric compounds depends on the number of Lewis (QCO > 34 kJ/mol) and Bronsted sites (νOH = 3688 cm−1). An increase in their total amount on the catalyst surface leads to an increase in the rate of formation of oligomeric hydrocarbons. The amount of surface condensation products is determined by the concentration of strong aprotic sites with QCO > 35 kJ/mol. Alumina support samples with a high surface concentration of medium-strong Lewis sites, wedge-shaped or conical pores, and the preferential distribution of porometric volume in pores with a diameter of 5–15 nm are characterized by a significant ability to oligomerize unsaturated compounds. Catalysts that contain 0.5 wt % Na exhibit the lowest oligomerization ability and a high stabile activity in reactions of hydrogenation of diene and vinyl aromatic hydrocarbons in pyrolysis gasoline. For the selective hydrogenation of diene and vinyl aromatic hydrocarbons in pyrolysis gasoline, we recommend a catalyst with 0.5 wt % Pd supported from palladium acetylacetonate on δ-Al2O3 modified with 0.5 wt % sodium; it is characterized by the absence of wedge-shaped or conical pores, the preferential (60.7%) distribution of porometric volume in a range of dp > 15 nm, and a low aprotic acidity (L = 3.1 μmol/g), which contributes to the decrease in the amount of resulting condensation products (V = 3.6 μg/(gcat h)) and a high stable activity (DN = 0.68 g J2/100 g) in reactions of hydrogenation of unsaturated compounds.

NAD-dependent 1,2-propanediol dehydrogenase (EC 1.1.1.4) activity was detected in cell-free crude extracts of various propane-grown bacteria. The enzyme activity was much lower in 1-propanol-grown cells than in propane-grown cells of Pseudomonas fluorescens NRRL B-1244, indicating that the enzyme may be inducible by metabolites of propane subterminal oxidation. 1,2-Propanediol dehydrogenase was purified from propane-grown Ps. fluorescens NRRL B-1244. The purified enzyme fraction shows a single-protein band upon acrylamide gel electrophoresis and has a molecular weight of 760,000. It consists of 10 subunits of identical molecular weight (77,600). It oxidizes diols that possess either two adjacent hydroxy groups, or a hydroxy group with an adjacent carbonyl group. Primary and secondary alcohols are not oxidized. The pH and temperature optima for 1,2-propanediol dehydrogenase are 8.5 and 20-25 degrees C, respectively. The activation energy calculated is 5.76 kcal/mol. 1,2-Propanediol dehydrogenase does not catalyze the reduction of acetol or acetoin in the presence of NADH (reverse reaction). The Km values at 25 degrees C, pH 7.0, buffer solution for 1,2-propan1,2-propanediol dehydrogenase are 8.5 and 20-25 degrees C, respectively. The activation energy calculated is 5.76 kcal/mol. 1,2-Propanediol dehydrogenase does not catalyze the reduction of acetol or acetoin in the presence of NADH (reverse reaction). The Km values at 25 degrees C, pH 7.0, buffer solution for 1,2-propan1,2-propanediol dehydrogenase are 8.5 and 20-25 degrees C, respectively. The activation energy calculated is 5.76 kcal/mol. 1,2-Propanediol dehydrogenase does not catalyze the reduction of acetol or acetoin in the presence of NADH (reverse reaction). The Km values at 25 degrees C, pH 7.0, buffer solution for 1,2-propanediol and NAD are 2 X 10(-2) and 9 X 10(-5) M, respectively. The 1,2-propanediol dehydrogenase activity was inhibited by strong thiol reagents, but not by metal-chelating agents. The amino acid composition of the purified enzyme was determined. Antisera prepared against purified 1,2-propanediol dehydrogenase from propane-grown Ps. fluorescens NRRL B-1244 formed homologous precipitin bands with isofunctional enzymes derived from propane-grown Arthrobacter sp. NRRL B-11315, Nocardia paraffinica ATCC 21198, and Mycobacterium sp. P2y, but not from propane-grown Pseudomonas multivorans ATCC 17616 and Brevibacterium sp. ATCC 14649, or 1-propanol-grown Ps. fluorescens NRRL B-1244. Isofunctional enzymes derived from methane-grown methylotrophs also showed different immunological and catalytic properties.

Nineteen new C 2 to C 4 n -alkane-grown cultures were isolated from lake water from Warinanco Park, Linden, N.J., and from lake and soil samples from Bayway Refinery, Linden, N.J. Fifteen known liquid alkane-utilizing cultures were also found to be able to grow on C 2 to C 4 n -alkanes. Cell suspensions of these C 2 to C 4 n -alkane-grown bacteria oxidized 2-alcohols (2-propanol, 2-butanol, 2-pentanol, and 2-hexanol) to their corresponding methyl ketones. The product methyl ketones accumulated extracellularly. Cells grown on 1-propanol or 2-propanol oxidized both primary and secondary alcohols. In addition, the activity for production of methyl ketones from secondary alcohols was found in cells grown on either alkanes, alcohols, or alkylamines, indicating that the enzyme(s) responsible for this reaction is constitutive. The optimum conditions for in vivo methyl ketone formation from secondary alcohols were compared among selected strains: Brevibacterium sp. strain CRL56, Nocardia paraffinica ATCC 21198, and Pseudomonas fluorescens NRRL B-1244. The rates for the oxidation of secondary alcohols were linear for the first 3 h of incubation. Among secondary alcohols, 2-propanol and 2-butanol were oxidized at the highest rate. A pH around 8.0 to 9.0 was found to be the optimum for acetone or 2-butanone formation from 2-alcohols. The temperature optimum for the production of acetone or 2-butanone from 2-propanol or 2-butanol was rather high at 60°C, indicating that the enzyme involved in the reaction is relatively thermally stable. Metal-chelating agents inhibit the production of methyl ketones, suggesting the involvement of a metal(s) in the oxidation of secondary alcohols. Secondary alcohol dehydrogenase activity was found in the cell-free soluble fraction; this activity requires a cofactor, specifically NAD. Propane monooxygenase activity was also found in the cell-free soluble fraction. It is a nonspecific enzyme catalyzing both terminal and subterminal oxidation of n -alkanes.

NAD-linked alcohol dehydrogenase activity was detected in cell-free crude extracts from various propane-grown bacteria. Two NAD-linked alcohol dehydrogenases, one which preferred primary alcohols (alcohol dehydrogenase I) and another which preferred secondary alcohols (alcohol dehydrogenase II), were found in propane-grown Pseudomonas fluorescens NRRL B-1244 and were separated from each other by DEAE-cellulose column chromatography. The properties of alcohol dehydrogenase I resembled those of well-known primary alcohol dehydrogenases. Alcohol dehydrogenase II was purified 46-fold; it was homogeneous as judged by acrylamide gel electrophoresis. The molecular weight of this secondary alcohol dehydrogenase is 144,500; it consisted of four subunits per molecule of enzyme protein. It oxidized secondary alcohols, notably, 2-propanol, 2-butanol, and 2-pentanol. Primary alcohols and diols were also oxidized, but at a lower rate. Alcohols with more than six carbon atoms were not oxidized. The pH and temperature optima for secondary alcohol dehydrogenase activity were 8 to 9 and 60 to 70 degrees C, respectively. The activation energy calculated from an Arrhenius plot was 8.2 kcal (ca. 34 kJ). The Km values at 25 degrees C, pH 7.0, were 8.2 X 10(-6) M for NAD and 8.5 X 10(-5) M for 2-propanol. The secondary alcohol dehydrogenase activity was inhibited by strong thiol reagents and strong metal-chelating agents such as 4-hydroxymercuribenzoate, 5,5'-dithiobis(2-nitrobenzoic acid), 5-nitro-8-hydroxyquinoline, and 1,10-phenanthroline. The enzyme oxidized the stereoisomers of 2-butanol at an equal rate. Alcohol dehydrogenase II had good thermal stability and the ability to catalyze reactions at high temperature (85 degrees C). It appears to have properties distinct from those of previously described primary and secondary alcohol dehydrogenases.

Over 20 new strains of methane-utilizing bacteria were isolated from lake water and soil samples. Cell suspensions of these and of other known strains of methane-utilizing bacteria oxidized n -alkanes (propane, butane, pentane, hexane) to their corresponding secondary alcohols (2-propanol, 2-butanol, 2-pentanol, 2-hexanol). The product secondary alcohols accumulated extracellularly. The rate of production of secondary alcohols varied with the organism used for oxidation. The average rate of 2-propanol, 2-butanol, 2-pentanol, and 2-hexanol production was 1.5, 1.0, 0.15, and 0.08 μmol/h per 5.0 mg of protein in cell suspensions, respectively. Secondary alcohols were slowly oxidized further to the corresponding methylketones. Primary alcohols and aldehydes were also detected in low amounts (rate of production were 0.05 to 0.08 μmol/h per 5.0 mg of protein in cell suspensions) as products of n -alkane (propane and butane) oxidation. However, primary alcohols and aldehydes were rapidly metabolized further by cell suspensions. Methanol-grown cells of methane-utilizing bacteria did not oxidize n -alkanes to their corresponding secondary alcohols, indicating that the enzymatic system required for oxidation of n -alkanes was induced only during growth on methane. The optimal conditions for in vivo secondary alcohol formation from n -alkanes were investigated in Methylosinus sp. (CRL-15). The rate of 2-propanol and 2-butanol production was linear for the 40-min incubation period and increased directly with cell protein concentration up to 12 mg/ml. The optimal temperature and pH for the production of 2-propanol and 2-butanol were 40°C and pH 7.0. Metalchelating agents inhibited the production of secondary alcohols. The activities for the hydroxylation of n -alkanes in various methylotrophic bacteria were localized in the cell-free particulate fractions precipitated by centrifugation between 10,000 and 40,000 × g . Both oxygen and reduced nicotinamide adenine dinucleotide were required for hydroxylation activity. The metal-chelating agents inhibited hydroxylation of n -alkanes by the particulate fraction, indicating the involvement of a metal-containing enzyme system in the oxidation of n -alkanes. The production of 2-propanol from the corresponding n -alkane by the particulate fraction was inhibited in the presence of methane, suggesting that the subterminal hydroxylation of n -alkanes may be catalyzed by methane monooxygenase.

Cell-free particulate fractions derived from methylotrophic bacteria catalyze the oxygen- and reduced nicotinamide adenine dinucleotide-dependent epoxidation of alkenes and hydroxylation of alkanes. Evidence presented indicates that the hydroxylation and epoxidation reactions are catalyzed by the same or a similar metal-containing monooxygenase.

Methylobacterium sp. strain CRL-26 grown in a fermentor contained methane monooxygenase activity in soluble fractions. Soluble methane monooxygenase catalyzed the epoxidation/hydroxylation of a variety of hydrocarbons, including terminal alkenes, internal alkenes, substituted alkenes, branched-chain alkenes, alkanes (C 1 to C 8 ), substituted alkanes, branched-chain alkanes, carbon monoxide, ethers, and cyclic and aromatic compounds. The optimum pH and temperature for the epoxidation of propylene by soluble methane monooxygenase were found to be 7.0 and 40°C, respectively. Among various compounds tested, only NADH 2 or NADPH 2 could act as an electron donor. Formate and NAD + (in the presence of formate dehydrogenase contained in the soluble fraction) or 2-butanol in the presence of NAD + and secondary alcohol dehydrogenase generated the NADH 2 required for the methane monooxygenase. Epoxidation of propylene catalyzed by methane monooxygenase was not inhibited by a range of potential inhibitors, including metal-chelating compounds and potassium cyanide. Sulfhydryl agents and acriflavin inhibited monooxygenase activity. Soluble methane monooxygenase was resolved into three components by ion-exchange chromatography. All three compounds are required for the epoxidation and hydroxylation reactions.

Cell-free extracts derived from yeasts Candida utilis ATCC 26387, Hansenula polymorpha ATCC 26012, Pichia sp. NRRL-Y-11328 Torulopsis sp. strain A1 and Kloeckera sp. strain A2 catalyzed an NAD+-dependent oxidation of secondary alcohols (2-propanol, 2-butanol, 2-pentanol, 2-hexanol) to the corresponding methyl ketones (acetone, 2-butanone, 2-pentanone, 2-hexanone). We have purified a NAD+-specific secondary alcohol dehydrogenase from methanol-grown yeast, Pichia sp. The purified enzyme is homogenous as judged by polyacrylamide gel electro-phoresis. The purified enzyme catalyzed the oxidation of secondary alcohols to the corresponding methyl ketones in the presence of NAD+ as an electron acceptor. Primary alcohols were not oxidized by the purified enzyme. The optimum pH for oxidation of secondary alcohols by the purified enzyme is 8.0. The molecular weight of the purified enzyme as determined by gel filtration is 98000 and subunit size as determined by sodium dodecyl sulfate gel electrophoresis is 48 000. The activity of the purified secondary alcohol dehydrogenase was inhibited by sulfhydryl inhibitors and metal-binding agents.

Cell suspensions of yeasts, Candida utilis ATCC 26387, Hansenula polymorpha ATCC 26012, Pichia sp. NRRL-Y-11328, Torulopsis sp. strain A1, and Kloeckera sp. strain A2, grown on various C-1 compounds (methanol, methylamine, methylformate), ethanol, and propylamine catalyzed the oxidation of secondary alcohols to the corresponding methyl ketones. Thus, isopropanol, 2-butanol, 2-pentanol, and 2-hexanol were converted to acetone, 2-butanone, 2-pentanone, and 2-hexanone, respectively. Cell-free extracts derived from methanol-grown yeasts catalyzed an oxidized nicotinamide adenine dinucleotide-dependent oxidation of secondary alcohols to the corresponding methyl ketones, Primary alcohols were not oxidized. The effect of various environmental factors on the production of methyl ketones from secondary alcohols by methanol-grown Pichia sp. was investigated.

Cell suspensions of methane-utilizing bacteria grown on methane oxidized n -alkanes (propane, butane, pentane, hexane) to their corresponding methylketones (acetone, 2-butanone, 2-pentanone, 2-hexanone). The product methylketones accumulated extracellularly. The rate of production of methylketones varied with the organism used for oxidation; however, the average rate of acetone, 2-butanone, 2-pentanone, and 2-hexanone production was 1.2, 1.0, 0.15, and 0.025 μmol/h per 5.0 mg of protein in cell suspensions. Primary alcohols and aldehydes were also detected in low amounts as products of n -alkane (propane and butane) oxidation, but were rapidly metabolized further by cell suspensions. The optimal conditions for in vivo methylketone formation from n -alkanes were compared in Methylococcus capsulatus (Texas strain), Methylosinus sp. (CRL-15), and Methylobacterium sp. (CRL-26). The rate of acetone and 2-butanone production was linear for the first 60 min of incubation and directly increased with cell concentration up to 10 mg of protein per ml for all three cultures tested. The optimal temperatures for the production of acetone and 2-butanone were 35°C for Methylosinus trichosporium sp. (CRL-15) and Methylobacterium sp. (CRL-26) and 40°C for Methylcoccus capsulatus (Texas). Metal-chelating agents inhibited the production of methylketones, suggesting the involvement of a metal-containing enzymatic system in the oxidation of n -alkanes to the corresponding methylketones. The soluble crude extracts derived from methane-utilizing bacteria contained an oxidized nicotinamide adenine dinucleotide-dependent dehydrogenase which catalyzed the oxidation of secondary alcohols.

A soil microorganism, identified as Acinetobacter calcoaceticus , was cultivated on ethanol as a sole source of carbon. This organism grew with a maximum specific growth rate of 0.7/h. The pH optimum for growth was between 6.5 and 7.5, and the temperature optimum was between 32 and 35 C. Ethanol metabolism by this organism was inducible by ethanol, and the presence of acetate led to the repression of ethanol dehydrogenase. At higher cell densities the cessation of growth on ethanol was accompanied by the accumulation of acetate or acetaldehyde, or both. These accumulations were attributed to a reduction in the magnesium or sulfur content of the medium and a lack of feedback inhibition by acetate of alcohol dehydrogenase.

The microbiological 2β-hydroxylation of a number of steroids by Gnomonia fragariae is reported. The conformation of ring A in these 2β-hydroxylated steroids is discussed.

Lampen , J. O. (Rutgers, The State University, New Brunswick, N.J.), Peter M. Arnow, Zofia Borowska, and Allen I. Laskin . Location and role of sterol at nystatin-binding sites. J. Bacteriol. 84: 1152–1160. 1962.—The polyene antifungal antibiotics nystatin and N -acetylcandidin were bound rapidly at 0 C by isolated cell walls and derived polysaccharides or by protoplast membranes from Saccharomyces cerevisiae strain LK2G12. These binding sites were relatively inaccessible or unreactive in the intact cell, since polyene uptake by protoplasts, log-phase cells, or stationary-phase cells was slow, especially at 0 C. Binding by the membrane appears to be the critical event in cell damage; thus, uptake of nystatin by the cell wall may actually be protective. Binding by all cell forms showed little reversibility. Bound radioactive nystatin or N -acetyl (1-C 14 ) candidin was not displaced during incubation of log-phase yeast cells with a large excess of unlabeled polyene. Saturation of the polyenic moiety of nystatin to form the perhydro compound eliminated almost completely the affinity of the molecule for the yeast cell. Essentially all of the polyene bound by protoplasts was present on the membrane. It was removed by treatment of the protoplasts with the sterol-complexing agent digitonin. A variety of evidence is offered that the binding site on the membrane contains a sterol. (The membrane sterol was mostly unesterified ergosterol.) This hypothesis is consistent with the ability of certain exogenous sterols to complex with polyenes and prevent their binding and growth-inhibiting action for fungi. The bound sterol of the wall structure may also participate in polyene binding, although a possible function of the wall polysaccharides cannot be excluded. The specific binding structure(s) appears to be absent from bacteria, since nystatin was not taken up even by heated or benzene-treated bacteria or by bacterial protoplasts. It should be noted that bacteria, which are insensitive to the polyene antibiotics, generally contain only traces of sterol, if any. Considerable quantities of sterol are present in fungi, algae, certain protozoa, and animal cells, all of which are sensitive in some degree.

Nicotine adenine dinucleotide-linked primary alcohol dehydrogenase and a newly discovered secondary alcohol dehydrogenase coexist in most strains of methanol-grown yeasts. Alcohol dehydrogenases from methanol-grown yeasts oxidize (--)-2-butanol preferentially over its (+) enantiomorph. This is substantially different from alcohol dehydrogenases from bakers' yeast and horse liver.

Methylocystis parvus OBBP, an obligate methylotroph originally isolated as a methane-utilizing bacterium, was cultivated on methanol as a sole source of carbon. After adaptation to high methanol levels, this organism grew on methanol with a maximum specific growth rate of 0.65 h −1 . The pH optimum for growth was between 7 and 9, and the temperature optimum was between 30 and 37°C. Methanol concentrations higher than 5% (by weight) were toxic. Formaldehyde, at a concentration greater than 1 mM, inhibited growth. Formate was neither a substrate nor an inhibitor. An extracellular viscous heteropolysaccharide was produced during growth. The maximum production of the total biomass was 14.5 g (dry weight) per liter of broth. The dried biomass contained 22% (wt/wt) crude protein and 62% (wt/wt) polysaccharide. The main components of the polysaccharide were d -glucose (82%) and l -rhamnose (14%).

In the course of our studies on methylotrophs, microorganisms that grow on methane and on other C1 compounds, we discovered that cell suspensions of methane-grown bacteria have the ability to oxidize gaseous 1-alkenes to their corresponding 1,2-epoxyalkanes, as well as to hydroxylate not only methane, but also the other gaseous alkanes (1). Thus, ethylene, propylene, 1-butene, and butadiene are converted to expodies, and methand, ethane, propane, and butane are hydroxylated; both primary and secondary alcohol products were detected. The product epoxides are not further metabolized and they accumulate extracellularly.

Acinetobacter calcoaceticus was grown on ethanol in a chemostat as a model system for single-cell protein production. The substrate yield coefficient ( Y s , grams of biomass/gram of ethanol), protein yield coefficient ( Y p , grams of protein/gram of ethanol), and biomass composition were measured as a function of the specific growth rate. Nucleic acid, protein, Y p , and Y s all increased at higher growth rates. Although protein content increased only 14% (from 53 to 67%), Y p almost doubled over the same range of growth rates. The increase in Y p was due to the higher protein content of the biomass and to higher values of Y s . The higher values of Y s were attributed to maintenance metabolism, and the value of the maintenance coefficient was found to be 0.11 g of ethanol per g of cell per h. When A. calcoaceticus was cultivated under a phosphorus limitation protein content, Y p and Y s were lower than in carbon-limited cultures. It was concluded that a single-cell protein fermentation using A. calcoaceticus should be operated at a high growth rate under ethanol-limiting conditions in order to maximize both the protein content of the biomass and the amount of biomass and/or protein made from the substrate.