513-85-9Relevant articles and documents
Radical-regulating and antiviral properties of ascorbic acid and its derivatives
Brinkevich, Sviatoslav D.,Boreko, Eugene I.,Savinova, Olga V.,Pavlova, Natalia I.,Shadyro, Oleg I.
, p. 2424 - 2427 (2012)
The ability of ascorbic acid and a number of its derivatives to suppress replication of Herpes simplex virus type I was investigated in human rhabdomyosarcoma cell line. In parallel, interaction of the test compounds with carbon- and oxygen-centered radicals formed on radiolysis of hydroxyl-containing organic compounds was studied using the steady state radiolysis method. It has been shown that 2-O-glycoside of ascorbic acid, displaying marked antiviral properties against Herpes simplex virus type I, is also capable of inhibiting fragmentation and recombination reactions of α-hydroxyl-containing carbon-centered radicals while not affecting processes involving oxygen-centered radicals.
The effects of ascorbic acid on homolytic processes involving α-hydroxyl-containing carbon-centered radicals
Brinkevich,Shadyro
, p. 6448 - 6450 (2008)
Effects of ascorbic acid and 5,6-O-isopropylidene-2,3-O-dimethylascorbic acid on final product formation in radiolysis of ethanol, aqueous solutions of ethanol, ethylene glycol, α-methylglycoside, maltose, α-glycerophosphate, and α-glucose phosphate were studied. It was found that ascorbic acid is able to suppress reactions involving various α-hydroxyl-containing carbon-centered radicals and depending on the experimental conditions can either oxidize or reduce α-hydroxyethyl radicals.
Reactions of cyclopentanone, γ-butyrolactone, and their derivatives with α-hydroxyethyl radicals
Brinkevich,Reztsov,Shadyro
, p. 303 - 309 (2014)
The interaction of cyclopentanone, 2-cyclopentenone, 1,3-cyclopentanedione, 3-methyl-1,2-cyclopentanedione, γ-butyrolactone, 2(5H)-furanone, ascorbic acid, and 5,6-O-isopropylidenyl-2-3-O-dimethylascorbic acid with α-hydroxyethyl radicals (α-HER) generated during the radiolysis of deaerated ethanol has been studied in the continuous irradiation mode. The test compounds, except γ-butyrolactone, oxidize α-HER. 2(5H)-Furanone and 2-cyclopentenone give hydroxyethylation products via the free-radical chain mechanism. In contrast to 2(5H)-furanone and 2-cyclopentenone, ascorbic and 5,6-O-isopropylidenyl-2,3-O-dimethyl-L-ascorbic acids are weaker oxidants for α-HER and attach these radicals at the multiple carbon-carbon bonds.
Effects of different techniques of malolactic fermentation induction on diacetyl metabolism and biosynthesis of selected aromatic esters in cool- climate grape wines
Lasik-Kurdys, Ma?gorzata,Majcher, Ma?gorzata,Nowak, Jacek
, (2018)
Thr effects of different malolactic bacteria fermentation techniques on the bioconversion of aromatic compounds in cool-climate grape wines were examined. During three wine seasons, red and white grape wines were produced using various malolactic fermentation induction techniques: Coinoculation, sequential inoculation, and spontaneous process. Volatile compounds (diacetyl and the products of its metabolism, and selected ethyl fatty acid esters) were extracted by solid phase microextraction. Compounds were identified with a multidimensional gas chromatograph-GC × GC-ToFMS with ZOEX cryogenic (N2) modulator. Sensory evaluation of the wines was also performed. It was found that the fermentation-derived metabolites studied were affected by the malolactic bacteria inoculation regime. Quantitatively, ethyl lactate, diethyl succinate, and ethyl acetate dominated as esters with the largest increase in content. The total concentration of ethyl esters was highest for the coinoculation technique, while the highest concentration of diacetyl was noted for the spontaneous technique. Controlled malolactic fermentation, especially using the coinoculation technique, can be proposed as a safe and efficient enological practice for producing quality cool-climate grape wines enriched with fruity, fresh, and floral aromas.
Particle size and surface chemistry in photoelectrochemical reactions at semiconductor particles
Müller,Majoni,Memming,Meissner
, p. 2501 - 2507 (1997)
In the present paper reactions at small and large ZnS particles have been investigated. It has been shown that ethanol is selectively oxidized at large (micrometer) particles to acetaldehyde without side products by a "two hole" process. In the case of nanometer particles the primarily formed α-hydroxyethyl radicals in a "one hole" process undergo a secondary reaction, i.e., the dimerization and disproportionation of the free radicals. It has been shown that a two hole process on nanometer particles becomes impossible because the time interval between two successive photon absorption incidents which lead to a successful hole transfer process in a 1-nm particle is much longer than the maximum lifetime of the α-hydroxyethyl radicals formed in the first step. The different mechanisms of ethanol oxidation and the influence of surface chemistry are discussed in detail.
Efficient production of acetoin by the newly isolated Bacillus licheniformis strain MEL09
Liu, Yongfeng,Zhang, Shuling,Yong, Yang-Chun,Ji, Zhixia,Ma, Xin,Xu, Zhenghong,Chen, Shouwen
, p. 390 - 394 (2011)
In this study, a new bacterial strain MEL09, which produces acetoin at high concentrations, was isolated from solid cultures of traditional Chinese vinegar. Based on physiological and biochemical characteristics as well as the 16S rDNA gene sequence, strain MEL09 was identified as Bacillus licheniformis. To improve acetoin production by B. licheniformis MEL09, medium composition and culture conditions were optimized by varying one factor at a time and using orthogonal array tests. Under these optimized conditions, the maximum acetoin concentration achieved was 41.26 g l-1, with 41.26% glucose conversion efficiency (84.39% of theoretical glucose conversion efficiency). This increase is 84.86% over the initial condition and is, to our knowledge, the highest acetoin level ever reported using fermentation methods.
Electrosynthesis of 2,3-butanediol and methyl ethyl ketone from acetoin in flow cells
Ochoa-Gómez, José R.,Fernández-Carretero, Francisco,Río-Pérez, Francisca,García-Luis, Alberto,Roncal, Tomás,García-Suárez, Eduardo J.
, p. 164 - 177 (2019)
Acetoin could shortly become a platform molecule due to current progress in fermentation technology, the megatrend for shifting from an oil-based economy to the one based on biomass, the quest for green manufacturing processes and its two highly reactive carbonyl and hydroxyl moieties. In this paper, the successful electro-conversion of acetoin into two valuable chemicals, 2,3-butanediol (2,3-BD) and methyl ethyl ketone (MEK), at a constant electrical current in an aqueous phase at room temperature using both divided and undivided 20 cm2 filter-press flow cells under experimental conditions suitable for industrial production is reported. Cathode material is the key parameter to drive the electroreduction towards one or another chemical. 2,3-BD is the major chemical produced by electrohydrogenation when low hydrogen overvoltage cathodes, such as Pt and Ni, of high surface areas obtained by PVD coating on a carbon gas diffusion layer are used, while MEK is the principal product produced by electrohydrogenolysis when high hydrogen overvoltage cathodes, such as graphite, Pb and Cd foils, are employed. 2,3-BD and MEK can be obtained, respectively, in 92.8% and 85.7% selectivities, 71.7% and 80.4% current efficiencies, with 1.21 and 1.08 kg h-1 m-2 productivities and power consumptions of 2.94 and 4.1 kWh kg-1 using undivided cells and aqueous K2HPO4 electrolysis media at pH values of 3.6 and 5.5. The reported electroconversion of acetoin is highly flexible because 2,3-BD and MEK can be produced by changing just the cathode but using the same cell, with the same electrolyte at the same current density.
Amplified Rate Acceleration by Simultaneous Up-Regulation of Multiple Active Sites in an Endo-Functionalized Porous Capsule
Kopilevich, Sivil,Müller, Achim,Weinstock, Ira A.
, p. 12740 - 12743 (2015)
Using the hydrolysis of epoxides in water as a model reaction, the effect of multiple active sites on Michaelis-Menten compliant rate accelerations in a porous capsule is demonstrated. The capsule is a water-soluble Ih-symmetry Keplerate-type complex of the form, [{MoVI6O21(H2O)6}12{MoV2O4(L)}30]42-, in which 12 pentagonal "ligands," {(MoVI)MoVI5O21(H2O)6}6-, are coordinated to 30 dimolybdenum sites, {MoV2O4L}1+ (L = an endohedrally coordinated ν2-bound carboxylate anion), resulting in 20 Mo9O9 pores. When "up-regulated" by removal of ca. one-third of the blocking ligands, L, an equal number of dimolybdenum sites are activated, and the newly freed-up space allows for encapsulation of nearly twice as many substrate guests, leading to a larger effective molarity (amplification), and an increase in the rate acceleration (kcat/kuncat) from 16,000 to an enzyme-like value of 182,800.
Properties of a 2,3-butanediol dehydrogenase from taiwanofungus camphorata
Ken, Chuian-Fu,Tsai, Wei-Wei,Wen, Lisa,Sheu, Dey-Chyi,Lin, Chi-Tsai
, p. 443 - 448 (2015)
2,3-Butanediol dehydrogenase (Bdh) plays important roles in reduction of acetoin to 2,3-butanediol, an important platform chemical with many industrial applications. Here, a TcBdh cDNA (1348 bp, GenBank accession JF896462) encoding a putative Bdh was cloned from Taiwanofungus camphorata. The deduced amino acid sequence is similar to the Bdhs from other species. A 3-D structural model of TcBdh has been constructed based on the known structure of Pseudomonas putida formaldehyde dehydrogenase (PpFdh, PDB code 1KOL). To characterize the TcBdh protein, the coding region was subcloned into an expression vector pYEX-S1 and transformed into Saccharomyces cerevisiae. The recombinant His6-tagged TcBdh was expressed and purified by Ni2+-nitrilotriacetic acid Sepharose. The purified enzyme showed a single band of 49 kDa on 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The Michaelis constant (KM) value of the recombinant enzyme for acetoin was 8.5 mM. The enzyme's optical pH was 6. The thermal inactivation of the enzyme showed a half-life of 5.3 min at 45°C.
Selective Photocatalytic C-C Coupling of Bioethanol into 2,3-Butanediol over Pt-Decorated Hydroxyl-Group-Tunable TiO2 Photocatalysts
Yang, Pengju,Zhao, Jianghong,Cao, Baoyue,Li, Li,Wang, Zhijian,Tian, Xuxia,Jia, Suping,Zhu, Zhenping
, p. 2384 - 2390 (2015)
2,3-Butanediol (2,3-BD) was synthesized through TiO2-photocatalytic C-C coupling of bioethanol synchronously with the liberation of an energy H2 molecule in an anaerobic atmosphere. It was found that the selectivity of 2,3-BD is controlled by the amount of .OH. The less the .OH, the higher the 2,3-BD selectivity. Furthermore, it was revealed that the amount of .OH increases with the increasing of the surface OH groups on TiO2 photocatalyst. The introduction of water is in favor of the C-C coupling pathway. This can be attributed to the stronger interaction between water and TiO2, which is beneficial to recovering the OH groups and promoting the desorption of .CH(OH)CH3 intermediates, thus suppressing the thermodynamically favorable overoxidation of .CH(OH)CH3 into acetaldehyde and promoting the C-C coupling into 2,3-BD. Based on the findings, the 2,3-BD selectivity was greatly enhanced from approximately 2.6 % to approximately 65 % over Degussa P25-TiO2 photocatalyst through fluorine substitution of surface OH groups.
