Conversion Of Maleic Acid Research Articles

Factors influencing catalytic wet peroxide oxidation of maleic acid in aqueous phase over copper/micelle templated silica-3-aminopropyltrimethoxysilane catalyst

Catalytic wet peroxide oxidation (CWPO) of initial maleic acid feed concentration (0.005 to 0.03 M) was carried out in a temperature range of 20-50 degrees Celsius, on micelle templated silica-3-aminopropyltrimethoxysilane (MTS-AMP) supported copper catalyst. The influence of various operating parameters such as initial feed concentration of maleic acid, temperature, catalyst loading and the stability of the catalyst were investigated. CWPO reactions were performed in a stirred batch reactor at an atmospheric pressure in the presence of H(2)O(2) as an oxidant. Total conversion of maleic acid into acetic acid was obtained under mild conditions (i.e. atmospheric pressure and 40 degrees Celsius). Blank experiments showed no measurable maleic acid conversion (i.e. only approximately 0.5% conversion of initial maleic acid), indicating that a significant oxidation reaction of maleic acid is enhanced by the presence of a catalyst. Copper on micelle templated silica-3-aminopropyltrimethoxysilane catalyst therefore was found to be suitable for aqueous phase oxidation of maleic acid with 100% of maleic acid conversion.

Kinetic model of hydrogen generation by Rhodobacter sphaeroides in the presence of NH4+ ions

To examine the effects of ammonium ion concentration and illumination intensity on the effectivness of the hydrogen generation process of Rhodobacter sphaeroides. In all experiments the amount of evolved hydrogen, biomass growth, concentration of ammonium ions, pH and chemical oxygen demand were measured. A nonstructural kinetic model was applied in description of biomass growth, the amount of evolved hydrogen and consumption of organic compounds and ammonium ions. An increase of ammonium ions concentration resulted in a decrease of maximal specific hydrogen potential production. At higher ammonium ion concentrations, no hydrogen evolution was observed. The efficiency of malic acid conversion into hydrogen and the PHB content in the biomass were the highest with lower concentrations of nitrogen compounds. The presence of ammonium ions inhibits hydrogen photogeneration. A good agreement between the experimental data and model simulations were obtained. In all cases, hydrogen evolution started after an exhaustion of ammonium ions and the increase was proportional to the C/N ratio in the medium. The accumulation of PHB competes with the hydrogen evolution process while the conversion of acids into biomass was limited at higher levels of hydrogen generation. Confirmation of the suitability of the selected model for kinetic studies of hydrogen photoevolution.

Malic acid photocatalytic degradation using a TiO 2-coated optical fiber reactor

A photoreactor containing a bundle of TiO 2-coated optical fibers was employed for the photocatalytic degradation of malic acid, a polycarboxylic acid found in fermentation processes and in biomass. TiO 2 film was coated on optical fiber using a dip-coating method. The kinetic behavior of malic acid conversion in this study was found to follow a first-order kinetics with a degradation rate of 6.8 × 10 −2 h −1. Laboratory experiments enabled one to detect six intermediates presented in five degradation pathways. Their evolution during the photocatalytic reaction was also investigated. The major one, malonic acid, is initiated by a decarboxylation (“photo-Kolbe”) reaction in the α-position with respect to the OH group followed by an OH addition. The others intermediates come from the same process or from H-abstraction or oxidation. The total organic carbon removal after 20 h of treatment was 21%. A high photonic efficiency of 6% was achieved for experiments operated in the optical fiber photoreactor due to the optimized light utilization.

Reduction of Maleic Acid to Succinic Acid on Titanium Cathode

Electrochemical reduction of maleic acid to succinic acid has been studied. The effect of (i) temperature, (ii) current density, (iii) concentration of H2SO4, and (iv) hydrodynamic conditions on conversion of maleic acid and current efficiency has been studied. The reaction was best carried out electrochemically at 40 °C at a current density of 625 A m-2. The effect of recycling the electrolyte, on conversion and current efficiency, has been reported. Conversion of maleic acid and current efficiency are affected marginally up to the fifth reuse. A material balance has been presented for these recycle studies.

The potential of positively-charged cellulose sponge for malolactic fermentation of wine, using Oenococcus oeni.

Malolactic fermentation (MLF) is a secondary bioconversion developed in some wines involving malic acid decarboxylation. The induction of MLF in wine by cultures of free and immobilized Oenococcus oeni cells was investigated. This work reports on the effect of surface charges in the immobilization material, a recently described fibrous sponge, as well as the pH and the composition of the media where cells are suspended. A chemical treatment provided positive charge to the sponges (DE or DEAE) and gave the highest cell loadings and subsequent resistance to removal. Preculture media to grow the malolactic bacteria before the immobilization procedure were also evaluated. We have established favorable conditions for growth (Medium of Preculture), suspension solution (Tartrate-Phosphate Buffer), suspension pH (3.5-5.5) and immobilization matrix (DE or DEAE cellulose sponge) to induce MLF in red wine. The use of a semi-continuous system permitted a high-efficiency malic acid conversion by 2 x 10(9) cfu sponge(-)(1) in at least four subsequent batch fermentations.

Catalytic wet air oxidation of carboxylic acids at atmospheric pressure

Catalytic wet air oxidation of carboxylic acids (maleic acid, oxalic acid and formic acid) was carried out in a batch reactor operated at 160 psi or atmospheric pressure. Pt/Al 2O 3 and the sulfonated poly(styrene-co-divinylbenzene) resin were used as catalysts. Maleic acid was proved to be a refractory substance which could not be oxidized on the Pt/Al 2O 3 catalyst at all atmoshperic pressure, and needed high pressure and high temperature operation for its oxidation. On the contrary, oxalic acid and formic acid were readily oxidized into carbon dioxide and water at 353 K and atmospheric pressure. The pathways of maleic acid oxidation were proposed, and the conversion of maleic acid into oxalic acid was the rate-determining step. When the sulfonated resin catalyst was present together with the Pt/Al 2O 3 catalyst, maleic acid could be oxidized at 353 K and atmospheric pressure. The sulfonated resin catalyst was suggested to hydrolyze maleic acid into readily oxidizable compounds.

Continuous malolactic fermentation by Oenococcus Oeni entrapped in LentiKats

A continuous process to deacidify apple juices and cider was developed by entrapping Oenococcus oeni in LentiKats, a new polyvinyl alcohol hydrogel. For a residence time of 0.55 h, malic acid was completely converted into lactic acid when the LentiKats bioreactor was fed with apple juice at pH 4.46 and 3.95 and thirty three percent of initial malic acid (6.7 g l−1) was converted when the initial apple juice pH was 2.30. The optimal malolactic activity of this bioreactor was obtained at 30 °C and a 50% reduction in malic acid conversion was measured between 15 °C and 20 °C, at a residence time of 0.3 h. The LentiKats bioreactor gave better performance than continuous reactor with Oenococcus oeni immobilised in alginate beads (specific malic acid consumption increased by a factor of 4.6) due to the increase of the ratio external surface to volume, allowing better mass transfer.

The malolactic fermentation in the wines of Naoussa (Greece). Study of lactic acid bacteria

<p style="text-align: justify;">The red wine« Appellation d'Origine Naoussa de qualité supérieure » stemming from the « Xynomavro » vine cultivated in this wine-growing region of western Macedonia (Greece) needs the advantages coming of malolatic fermentation. This wine, in spite of its incontestable qualities has a strong astringent and a high level of acidity, the malic acid contributing essentially to these two characters.</p><p style="text-align: justify;">Because of the interest malolactic fermentation presents for this region, we have collaborated with the wine-producters to insure, at first, the generally admitted conditions which favour the evolution of malolactic fermentation, then to study it.</p><p style="text-align: justify;">The latter includes : a) the control of the conversion of malic acid into lactic acid by chromatography paper and b) the enumeration, isolation and identification of lactic acid bacteria.</p><p style="text-align: justify;">During this two-year-long research, 187 samples have been taken from 50 different tanks during 12 samplings. The isolation of lactic acid bacteria was done by plating dilutions of wine samples and their identification with the API system and other physico-chemical and enzymatic methods.</p><p style="text-align: justify;">Data processing has been done by computer and given a strain group distribution according to their similarity.</p><p style="text-align: justify;">The results show that the homofermentative lactic acid bacteria - mainly <em>Lactobacillus plantarum</em> - are more numerous than the heterofermentative ones before the malolactic fermentation. They decrease during the fermentative process and disappear with its completion.</p><p style="text-align: justify;">The heterofermentative lactic aeid baeteria, whose main specie is <em>Leuconostoc oenos</em> evolves inversely.</p><p style="text-align: justify;">A low increase of <em>Pediococcus</em> has been observed too after the beginning of malolactic fermentation. A statistical analysis confirms the main points of this research.</p><p style="text-align: justify;">The application of malolactic fermentation becomes more efficient the second year; it is favoured in press-wines and for temperatures kept at 20-25°C; the bacteria population is also increased.</p><p style="text-align: justify;">The persued reduction of total acidity in wines, which underwent malolactic fermentation, was considerable.</p>

Selection of Streptococcus lactis Mutants Defective in Malolactic Fermentation

An enrichment medium and a new sensitive medium were developed to detect malolactic variants in different strains of lactic bacteria. Factors such as the concentration of glucose and l-malate, pH level, and the type of indicator dye used are discussed with regard to the kinetics of malic acid conversion to lactic acid. Use of these media allowed a rapid and easier screening of mutagenized streptococcal cells unable to ferment l-malate. A collection of malolactic-negative mutants of Streptococcus lactis induced by UV, nitrosoguanidine, or transposonal mutagenesis were characterized. The results showed that several mutants were apparently defective in the structural gene of malolactic enzyme, whereas others contained mutations which may either inactivate a putative permease or affect a regulatory sequence.

Temperature Features of Enzymes Affecting Crassulacean acid Metabolism

Enzymes involved in malic acid production via a pathway with 2 carboxylation reactions and in malic acid conversion via total oxidation have been demonstrated in mitochondria of Bryophyllum tubiflorum Harv. Activation of the mitochondria by Tween 40 was necessary to reveal part of the enzyme activities. The temperature behavior of the enzymes has been investigated, revealing optimal activity of acid-producing enzymes at 35 degrees . Even at 53 degrees the optimum for acid-converting enzymes was not yet reached. From the simultaneous action of acid-producing and acid-converting enzyme systems the overall result at different temperatures was established. Up to 15 degrees the net result was a malic acid production. Moderate temperatures brought about a decrease in this accumulation, which was partly accompanied by a shift to isocitrate production, while at higher temperatures total oxidation of the acids exceeded the production.

The Malo-Lactic Fermentation in New York State Wines

Wines from <i>Vitis labrusca</i> grapes and their hybrids produced in New York State were examined to determine the incidence of malo-lactic fermentation. Ninety-six samples of partially ameliorated varietal wines were analyzed for organic acids by paper chromatography. Forty-five percent had undergone a malo-lactic fermentation. The incidence was much greater in red wines than in white wines. There was a marked difference in incidence among the wineries involved, and the correlation between must handling procedures and incidence of malo-lactic fermentation was noted. The time interval between the alcoholic fermentation and a malo-lactic fermentation was found to be of the order of three weeks. The conversion of malic acid to lactic acid in these wines occurred rapidly, once started, and coincided with the development of a bacterial population in excess of a million organisms per milliliter. Three types of lactic acid organisms have been isolated, a heterofermentative rod, a homofermentative rod, and a homofermentative coccus. Characteristics of musts were reported. In the new wines, the relationship between total acidity and pH, and the incidence of malo-lactic fermentation was noted.

Induction of Malo-Lactic Fermentation by Inoculation of Must and Wine with Bacteria

Two strains of lactic acid bacleria, previously isolated from California wines, were used to induce the malo-lactic fermentation in must and wine. Under the condition described, the malo-lactic fermentation was independent of the stage of the alcoholic fermentation at which the bacterial inoculations were made. The malolactic fermentation was much more rapid with ML 34 (<i>Leuconostoc</i> sp.) than with ML 30 (<i>Lactobacillus</i> sp.) The conversion of malic acid to lactic acid was made to occur in both dry wine and in must in the presence of SO₂ by the use of a large inoculum of bacteria. In no instances was the malo-lactic fermentation accompanied by any detrimental effect to the wines. Slight but chemically detectable increases of volatile acid occurred with the malolactic fermentation. There was no further increase in volatile acidity after the end of the malo-lactic fermentation, and fining was thus not necessary to halt further volatile acid formation.

Organic acid metabolism in cider and perry fermentations. I.—A preliminary study

AbstractThe organic acid constituents of cider‐apple and perry‐pear juices and the microbiological changes which they undergo during fermentation have been investigated using methods based on ion‐exchange and paper chromatography. The main changes observed during fermentation were the conversion of malic acid to lactic acid and of quinic acid to dihydroshikimic acid, both of which were brought about by lactic acid bacteria. These bacteria also broke down citric acid, present in considerable amount in some perry‐pear juices.

(114)ポリエステル化反応中におけるマレイン酸の転移について

(114)ポリエステル化反応中におけるマレイン酸の転移について