Production of succinic acid by anaerobiospirillum succiniciproducens

The effect of an external supply of carbon dioxide and pH on the production of succinic acid byAnaerobiospirillum succiniciproducens was studied. In a rich medium containing yeast extract and peptone, when the external carbon dioxide supply was provided by a 1.5M Na₂CO₃ solution that also was used to maintain the pH at 6.0, no additional carbon dioxide supply was needed. In fact, sparging CO₂ gas into the fermenter at 0.025 L/L-min or higher rates resulted in significant decreases in both production rate and yield of succinate. Under the same conditions, the production of the main by-product acetate was not affected by sparging CO₂ gas into the fermenter. The optimum pH (pH 6.0) for the production of succinic acid was found to be in agreement with results previously reported in the literature. Succinic acid production also was studied in an industrial-type inexpensive medium in which light steep water was the only source of organic nutrients. At pH 6.0 and with a CO₂ gas sparge rate of 0.08 L/L-min, succinate concentration reached a maximum of 32 g/L in 27 h with a yield of 0.99 g succinate/g glucose consumed.     

The effect of acetic acid on fuel ethanol production byZymomonas

Applied Biochemistry and Biotechnology - Acetic acid acts to promote uncoupling withZymomonas. At pH 5, 36% of acetic acid is in the uncharged and undissociated form (HAc), which is able to...     

The effect of lactic acid on fuel ethanol production byZymomonas

Efficient utilization of the pentosan fraction of hemicellulose from lignocellulosic feedstocks offers an opportunity to increase the yield and to reduce the cost of producing fuel ethanol. During prehydrolysis (acid hydrolysis or autohydrolysis of hemicellulose), acetic acid is formed as a consequence of the deacetylation of the acetylated moiety of hemicellulose. Recombinant Escherichia coli B (ATCC 11303), carrying the plasmid pLO1297 with pyruvate decarboxylase and alcohol dehydrogenase II genes from Zymomonas mobilis (CP4), converts xylose to ethanol with a product yield that approaches theoretical maximum. Although other pentose-utilizing microorganisms are inhibited by acetic acid, the recombinant E. coli displays a high tolerance for acetic acid. In xylose fermentations with a synthetic medium (Luria broth), where the pH was controlled at 7, neither yield nor productivity was affected by the addition of 10.7 g/L acetic acid. Nutrient-supplemented, hardwood (aspen) hemicellulose hydrolysate (40.7 g/L xylose) was completely fermented to ethanol (16.3 g/L) in 98 h. When the acetic acid concentration was reduced from 5.6 to 0.8 g/L, the fermentation time decreased to 58 h. Overliming, with Ca(OH)₂ to pH 10, followed by neutralization to pH 7 with sulfuric acid and removal of insolubles, resulted in a twofold increase in volumetric productivity. The maximum productivity was 0.93 g/L/h. The xylose-to-ethanol conversion efficiency and productivity in Ca(OH)₂-treated hardwood prehydrolysate, fortified with only mineral salts, were 94% and 0.26 g/L/h, respectively. The recombinant E. coli exhibits a xylose-to-ethanol conversion efficiency that is superior to that of other pentose-utilizing yeasts currently being investigated for the production of fuel ethanol from lignocellulosic materials.     

Thermodynamic study on the sublimation of succinic acid and of methyl- and dimethyl-substituted succinic and glutaric acids

The Knudsen mass-loss effusion technique was used to measure the vapour pressures at different temperatures of the following crystalline dicarboxylic acids: succinic acid, between T =  360.11 K and T =  375.14 K; methylsuccinic acid, between T =  343.12 K and T =  360.11 K; 2,2-dimethylsuccinic acid, between T =  350.11 K, and T =  365.11 K; 2-methylglutaric acid, between T =  338.38 K and T =  347.63 K; and 2,2-dimethylglutaric acid between T =  342.18 K and T =  352.66 K. From the temperature dependence of the vapour pressure, the standard molar enthalpies of sublimation were derived by the Clausius–Clapeyron equation and the molar entropies of sublimation at equilibrium pressures were calculated. Using estimated values for the heat capacity differences between the gas and the crystal phases of the studied compounds, the standard, p^o =  10⁵Pa, molar enthalpies, entropies and Gibbs energies of sublimation at T =  298.15 K, were derived:     

Continuous production of succinic acid by a fumarate-reducing bacterium immobilized in a hollow-fiber bioreactor

Enterococcus faecalis RKY1, a fumarate-reducing bacterium, was immobilized in an asymmetric hollow-fiber bioreactor (HFBR) for the continuous production of succinic acid. The cells were inoculated into the shell side of the HFBR, which was operated in transverse mode. Since the pH values in the HFBR declined during continuous operation to about 5.7, it was necessary to change the feed pH from 7.0 to 8.0 after 24 h of operation in order to enhance production of succinic acid. During continuous operation with a medium containing fumarate and glycerol, the productivity of succinate was 3.0–10.9 g/(L·h) with an initial concentration of 30 g/L of fumarate, 4.9–14.9 g/(L·h) with 50 g/L of fumarate, and 7.2–17.1 g/(L·h) with 80 g/L of fumarate for dilution rates between 0.1 and 0.4 h⁻¹. The maximum productivity of succinate obtained by the HFBR (17.1 g of succinate /[L·h]) was 1.7 times higher than that of the batch bioconversions (9.9 g of succinate /[L·h]) with 80 g/L of fumarate. Furthermore, the long-term stability of the HFBR was demonstrated with a continuously efficient production of succinate for more than 15 d (360 h).     

Surface-active properties of succinic acid monoalkyl derivatives

Surface activity, capability for micelle formation of sodium and calcium salts of succinic acid monoalkyl esters and monoalkyl amides in aqueous solutions, and their waterproofing action in the microflotation of the calcium-containing mineral apatite were studied. The results obtained have been compared with similar data for saturated monocarboxylic acids.     

The influence of the nature of the background electrolyte on the heat effects of dissociation of succinic acid

The results of calorimetric measurements were used to determine the heat effects of dissociation of succinic acid at 298.15 K and several ionic strength values in the presence of NaNO₃. The thermodynamic characteristics of dissociation at fixed ionic strength values and I = 0 were calculated.     

Enzymatic determination of succinic acid in foodstuffs

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Enzymatic determination of succinic acid in foodstuffs

     

Expression ofAscaris suum malic enzyme in a mutantEscherichia coli allows production of succinic acid from glucose

Applied Biochemistry and Biotechnology - The malic enzyme gene ofAscaris suum was cloned into the vector pTRC99a in two forms encoding alternative arnino-termini. The resulting plasmids, pMEAl and...     

Crystal structure of 2,2-dimethyl succinic acid.

The title compound crystallizes triclinically in space group of P1. The C2-COOH and C3-COOH molecular groups are planar. The crystal structure is stabilized by the formation of intermolecular (O-HO) hydrogen bonds.     

Bioconversion of fumaric acid to succinic acid by recombinantE. coli

Applied Biochemistry and Biotechnology - Succinic acid was produced efficiently from fumaric acid by a recombinantE. coli strain DH5αt/pGC1002 containing multicopy fumarate reductase genes....     

The cocrystal nicotinamide–succinic acid (2/1)

In the asymmetric unit of the crystal structure of nicotinamide–succinic acid (2/1), 2C₆H₆N₂O·C₄H₆O₄, there are two independent nicotinamide molecules in general positions and two half succinic acid molecules which lie about inversion centres. The structure contains acid–pyridine and amide–amide synthons with nicotinamide molecules forming ladders of alternating R₂²(8) and R₄²(8) rings linked through succinic acid to generate a corrugated hydrogen‐bonded sheet. This sheet is a common supramolecular unit found in other 2:1 nicotinamide–dicarboxylic acid cocrystals, but the presence of two crystallographically distinct nicotinamides with anti and syn conformations, forming two distinct sheets within the same structure, is a novel packing feature in this type of material.     

Polarographic determination of zinc and manganese in succinic acid

Summary Zinc and manganese develop well defined waves in 0.1 M succinic acid at pH 3.5 and 6.0, respectively. Both the waves are diffusion controlled in nature. Zn wave does not develop any maxima while Mn does, which is suppressed by using 0.005% gelatin. Their half-wave potentials are separated by 0.47 V, which renders their simultaneous determination possible.

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Polarographische Bestimmung von Zink und Mangan in Bernsteinsäure-Lösung

Zusammenfassung Zn und Mn geben gut ausgebildete diffusionskontrollierte Stufen in 0,1 M Bernsteinsäure-Lösung bei pH 3,5 bzw. 6,0. Zn entwickelt keine Maxima, während die von Mn durch 0,005% Gelatine unterdrückt werden. Da die Halbstufenpotentiale um 0,47 V auseinanderliegen, ist eine gleichzeitige Bestimmung beider Ionen möglich.

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Our sincere thanks are due to Dr. G. B. Singh, Head of Chemistry Department, B. H. U. for providing necessary facilities.     

Chemo-enzymatic synthesis of chiral 2-substituted succinic acid derivatives

Prochiral discrimination by the biocatalyst Alcalase^®, an enzyme preparation of subtilisin Carlsberg, was used to effect enantio- and regioselective monohydrolysis of a variety of (RS)-2-substituted succinate diesters to afford the corresponding half esters in modest to excellent enantiomeric excesses (>99%). Exploitation of malonate chemistry, as well as recycling of the unhydrolyzed isomer from the enantioselective hydrolysis, has resulted in a process which is both practical and economical.     

Supramolecular organogels formed by monochain derivatives of succinic acid

The monoalkyl chain derivatives of succinic acid self-assemble into ordered bilayer aggregates by forming dimers of hydrogen bonded carboxylic acid in a number of organic solvents and finally gelatinize the solvents. The gelation ability of each derivative was inspected. The morphologies of xerogels were investigated by scanning electron microscope (SEM). The microstructure of aggregates was studied by small angle X-ray diffraction (SA-XRD) and Fourier transform infrared spectroscopy (FT-IR). The results reveal that the intermolecular hydrogen bonds between neighboring molecules are critical factor in the process of organogelation.     

Local and global chirality at surfaces: succinic acid versus tartaric acid on Cu110

A detailed comparison of tartaric acid (HOOC-CHOH-CHOH-COOH) and succinic acid (HOOC-CH(2)-CH(2)-COOH) molecules on a Cu(110) surface is presented with a view to elucidate how the two-dimensional chirality exhibited by such robust, chemisorbed systems is affected when both OH groups of the former molecule are replaced with H groups, a stereochemical change that leaves the metal-bonding functionalities of the molecule untouched but destroys both chiral centers. It is found that this change does not significantly affect the thermodynamically preferred chemical forms that are adopted, namely the doubly deprotonated bicarboxylate at low coverages (theta 相似文献   

The standard enthalpies of formation of succinic acid and the products of its dissociation in aqueous solution

Direct calorimetric measurements of the heat effects of solution of crystalline succinic acid in water and solutions of potassium hydroxide were performed at 298.15 K. The standard enthalpies of formation of succinic acid and the products of its dissociation in aqueous solution were calculated.