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.     

Degradation of uric acid and 3-ribosyluric acid during treatment with charcoal

Uric acid and 3-ribosyluric acid at a concentration of 1.5 × 10^?4M were quantitatively adsorbed to charcoal, but were not recovered when the charcoal was washed with ethanol:water:NH₄OH (60:36:4), a solvent which readily eluted a number of other bases and nucleosides. With [2-¹⁴C]uric acid it was shown that the radioactivity was adsorbed to the charcoal and that [¹⁴C]allantoin was the primary product recovered after elution. Incubation of uric acid or 3-ribosyluric acid in the ethanol:water:NH₄OH did not result in any degradation. The elution of uric acid from charcoal with other eluents such as 7% phenol, 0.1 M NaOH, or ethanol:water:pyridine (50:40:10) also resulted in the conversion of uric acid to allantoin. It was concluded that when uric acid and 3-ribosyluric acid are adsorbed to charcoal and then eluted, there is a substantial conversion of these compounds to the corresponding allantoin.     

Optimal conditions for alkaline detoxification of dilute-acid lignocellulose hydrolysates

Alkaline detoxification strongly improves the fermentability of dilute-acid hydrolysates in the production of bioethanol from lignocellulose with Saccharomyces cerevisiae. New experiments were performed with NH₄OH and NaOH to define optimal conditions for detoxification and make a comparison with Ca(OH)₂ treatment feasible. As too harsh conditions lead to sugar degradation, the detoxification treatments were evaluated through the balanced ethanol yield, which takes both the ethanol production and the loss of fermentable sugars into account. The optimization treatments were performed as factorial experiments with 3-h duration and varying pH and temperature. Optimal conditions were found roughly in an area around pH 9.0/60°C for NH₄OH treatment and in a narrow area stretching from pH 9.0/80°C to pH 12.0/30°C for NaOH treatment. By optimizing treatment with NH₄OH, NaOH, and Ca(OH)₂, it was possible to find conditions that resulted in a fermentability that was equal or better than that of a reference fermentation of a synthetic sugar solution without inhibitors, regardless of the type of alkali used. The considerable difference in the amount of precipitate generated after treatment with different types of alkali appears critical for industrial implementation.     

Ammonium hydroxide detoxification of spruce acid hydrolysates

When dilute-acid hydrolysates from spruce are fermented to produce ethanol, detoxification is required to make the hydrolysates fermentable at reasonable rates. Treatment with alkali, usually by overliming, is one of the most efficient approaches. Several nutrients, such as ammonium and phosphate, are added to the hydrolysates prior to fermentation. We investigated the use of NH₄OH for simultaneous detoxification and addition of nitrogen source. Treatment with NH₄OH compared favorably with Ca(OH)₂, Mg(OH)₂, Ba(OH)₂, and NaOH to improve fermentability using Saccharomyces cerevisiae. Analysis of monosaccharides, furan aldehydes, phenols, and aliphatic acids was performed after the different treatments. The NH₄OH treatments, performed at pH 10.0, resulted in a substantial decrease in the concentrations of furfural and hydroxymethylfurfural. Under the conditions studied, NH₄OH treatments gave better results than Ca(OH)₂ treatments. The addition of an extra nitrogen source in the form of NH₄Cl at pH 5.5 did not result in any improvement in fermentability that was comparable to NH₄OH treatments at alkaline conditions. The addition of CaCl₂ or NH₄Cl at pH 5.5 after treatment with NH₄OH or Ca(OH)₂ resulted in poorer fermentability, and the negative effects were attributed to salt stress. The results strongly suggest that the highly positive effects of NH₄OH treatments are owing to chemical conversions rather than stimulation of the yeast cells by ammonium ions during the fermentation.     

Succinic Acid Production from Cheese Whey using Actinobacillus succinogenes 130 Z

Actinobacillus succinogenes 130 Z was used to produce succinic acid from cheese whey in this study. At the presence of external CO₂ supply, the effects of initial cheese whey concentration, pH, and inoculum size on the succinic acid production were studied. The by-product formation during the fermentation process was also analyzed. The highest succinic acid yield of 0.57 was obtained at initial cheese whey concentration of 50 g/L, while the highest succinic acid productivity of 0.58 g h⁻¹ L⁻¹ was obtained at initial cheese whey concentration of 100 g/L. Increase in pH and inoculum size caused higher succinic acid yield and productivity. At the preferred fermentation condition of pH 6.8, inoculum size of 5% and initial cheese whey concentration of 50 g/L, succinic acid yield of 0.57, and productivity of 0.44 g h⁻¹ L⁻¹ were obtained. Acetic acid and formic acid were the main by-products throughout the fermentation run of 48 h. It is feasible to produce succinic acid using lactose from cheese whey as carbon resource by A. succinogenes 130 Z.     

Succinic acid production from acid hydrolysate of corn fiber by Actinobacillus succinogenes

Dilute acid hydrolysate of corn fiber was used as carbon source for the production of succinic acid by Actinobacillus succinogenes NJ113. The optimized hydrolysis conditions were obtained by orthogonal experiments. When corn fiber particles were of 20 mesh in size and treated with 1.0% sulfuric acid at 121 °C for 2 h, the total sugar yield could reach 63.3%. It was found that CaCO₃ neutralization combined with activated carbon adsorption was an effective method to remove fermentation inhibitors especially furfural that presented in the acid hydrolysate of corn fiber. Only 5.2% of the total sugar was lost, while 91.9% of furfural was removed. The yield of succinic acid was higher than 72.0% with the detoxified corn fiber hydrolysate as the carbon source in anaerobic bottles or 7.5 L fermentor cultures. It was proved that the corn fiber hydrolysate could be an alternative to glucose for the production of succinic acid by A. succinogenes NJ113.     

Continuous wine making by γ-alumina-supported biocatalyst

The main objective of the present work was the removal of aluminum from wines produced by γ-alumina-supported yeast cells. Reagents such as Na₂CO₃, NH₄OH, albumin, and Ca(OH)₂ were used. Calcium in the presence of albumin was effective, whereas other reagents were not so effective. Because of the improved aroma and taste of distillates produced by γ-alumina-supported biocatalyst, volatile byproducts of distillates were analyzed. They were also assessed by sensory tests. Methanol, acetaldehyde, ethyl acetate, propanol-1, isobutyl alcohol, and amyl alcohols were determined in distillates. It was noted that the amounts of higher alcohols and amyl alcohols decreased as the temperature of fermentation dropped, leading to a product of improved quality and reduced toxicity.     

Production of high-purity carbon dioxide and sodium bicarbonate by lime cellar gas cleaning and chemical recycling: Process simulation and techno-economic analysis

The cement industry is responsible for 8% of total global CO₂ emissions, which mainly originate from limestone calcination and fuel combustion. In view of the application potential of using CO₂ to produce chemicals, this paper developed a novel process based on the Aspen Plus process simulation for the co-production of 99.99% CO₂ by means of Methyldiethanolamine (MDEA) absorption/desorption and NaHCO₃ by carbonization of CO₂, NH₃ and Na₂SO₄. The effects of absorption temperature, NH₃ and Na₂SO₄ feeding amount, crystallizer temperature and pressure on CO₂ capture rate and utilization rate were explored. The results showed that the best CO₂ capture rate was achieved when the cellar gas inlet temperature of the absorber tower was 37 °C; Saturated Na₂SO₄ solution was favorable for CO₂ absorption, and the CO₂ utilization rate increased with the increase of Na₂SO₄ dosage; NaHCO₃ yield decreased with the increase of crystallizing temperature, and the best NaHCO₃ yield was achieved when the crystallizer temperature was 35.5 °C; Crystallizing pressure had little impact on the reaction. Economic analysis showed that the project will start to be profitable in 6.48 years with a Net Return Rate (NRR) value of 13.51%. It indicates that the project has economic benefits and provides a new way to reduce CO₂ emissions from lime cellar gas.     

Effect of nutrient supplements addition on ethanol production from cheese whey usingCandida pseudotropicalis under batch condition

Candida pseudotropicalis ATCC 8619 was selected among nine strains of lactose fermenting yeast for the production of ethanol from cheese whey. The effects of three nutrients (ammonium sulfate (NH₄)₂SO₄, dipotassium hydrogen phosphate K₂HPO₄, yeast extract, and a combination of them) on the ethanol yield from cheese whey were investigated. The results indicated that no addition of nutrient supplement is necessary to achieve complete lactose utilization during the cheese whey ethanol fermentation. However, addition of a small concentration (0.005% w/v) of these supplements reduced the lag period and the total fermentation time and increased the specific growth rate of the yeast. Higher concentrations (0.01 and 0.015% w/v) of ammonium sulfate and dipotassium hydrogen phosphate inhibited the cell growth and reduced lactose consumption. The highest ethanol (21.17 g/L) was achieved using yeast extract at a concentration of 0.01% w/v, given a conversion efficiency of 98.3%. No indication of alcohol inhibition was observed in this study.     

Complex Carbonates of Iron(III)

The complex carbonates of iron(III) are shown to be anionic in nature. The solutions containing these complexes show a maximum absorbance at 460 nm. The complex carbonates of iron(III), viz., (i) K₆[Fe₂(OH)₂(CO₃)₅] · H₂O, — (ii) Na₂[Fe₃O₂(OH)₃(CO₃)₂], — (iii) K[Co(NH₃)₆]₂[Fe₃(OH)₄(CO₃)₆], — (iv) K₅[Co(NH₃)₆]₃[Fe₃(OH) ₄(CO₃)₆]₂, — (v) K[Co(NH₃)₆][Fe₂(OH)₄(CO₃)₃], and (vi) NH₄[Co(NH₃)₆][Fe₂(OH)₄(CO₃)₃] are isolated and studied by thermogravimetry. The infrared spectra of these compounds are recorded and probable band assignments made. Besides, the reaction between KHCO₃ and Fe(NO₃)₃ was studied through chemical and physicochemical methods.     

Polarographische Bestimmung von 1,5-Dihydroxy-4,8-dinitro-anthrachinon (DNA) und seines Isomeren 1,8-Dihydroxy-4,5-dinitro-anthrachinon (DNC)

Zusammenfassung Zur quantitativen Analyse der Isomeren DNA und DNC, des Substanzgemisches und von Mischungen mit anderen Nitroderivaten wird die Polarographie von 0,1–0,3 g-Proben in Pyridin in Gegenwart von 1. NH₄Cl, NH₄OH, Na₂SO₃ und Nigrosinlösung; 2. Na₂SO₃ und Nigrosinlösung und 3. NH₄Cl, NH₄OH, Na₃SO₃ und Gelatinelösung mit einer Genauigkeit von ± 3% und einer Empfindlichkeit von 10^–2 durchgeführt.

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Polarographic determination of 1,5-dihydroxy-4,8-dinitroanthraquinone (DNA) and its isomer 1,8-dihydroxy 4,5-dinitroanthraquinone(DNC)

Quantitative analysis is carried out with the isomeric compounds, there mixtures and mixtures with other nitro derivatives. 0.1 to 0.3 g samples are applied in pyridine and polarographic recording is performed in the presence of 1) NH₄Cl, NH₄OH, Na₂SO₃ and nigrosine, 2) Na₂SO₃ and nigrosine, 3) NH₄Cl, NH₄OH, Na₂SO₃ and gelatin. Accuracy is ± 3%, sensitivity 10^–2.

     

Effect of Nutrients on Fermentation of Pretreated Wheat Straw at very High Dry Matter Content by Saccharomyces cerevisiae

Wheat straw hydrolysate produced by enzymatic hydrolysis of hydrothermal pretreated wheat straw at a very high solids concentration of 30% dry matter (w/w) was used for testing the effect of nutrients on their ability to improve fermentation performance of Saccharomyces cerevisiae. The nutrients tested were MgSO₄ and nitrogen sources; (NH₄)₂SO₄, urea, yeast extract, peptone and corn steep liquor. The fermentation was tested in a separate hydrolysis and fermentation process using a low amount of inoculum (0.33 g kg^?1) and a non-adapted baker’s yeast strain. A factorial screening design revealed that yeast extract, peptone, corn steep liquor and MgSO₄ were the most significant factors in obtaining a high fermentation rate, high ethanol yield and low glycerol formation. The highest volumetric ethanol productivity was 1.16 g kg^?1 h^?1 and with an ethanol yield close to maximum theoretical. The use of urea or (NH₄)₂SO₄ separately, together or in combination with MgSO₄ or vitamins did not improve fermentation rate and resulted in increased glycerol formation compared to the use of yeast extract. Yeast extract was the single best component in improving fermentation performance and a concentration of 3.5 g kg^?1 resulted in high ethanol yield and a volumetric productivity of 0.6 g kg^?1 h^?1.     

Untersuchung der Bildung von Polyesteramiden aus Dicarbonsäure-anhydriden und Oxazolidinonen-2

The well-known reaction of dicarboxylic acid anhydrides with epoxides, catalyzed by bases and yielding linear polyesters, has been extended by a variation of the reactants. The reactions of succinic and phthalic anhydrides with N-substituted oxazolidinones-2, which by their tendency to split off CO₂ may be regarded as ethyleneimine derivatives, give in the presence of a few mole percent of LiCl at 200–220°C. within 5–10 hr. polyester amides of molecular weights up to 3.500 in nearly quantitative yield. The polymer yield corresponds to the CO₂ evolution indicating an equal consumption of oxazolidinone and anhydride in the reaction. The experimental activation energies of 22.8 and 20.2 kcal./mole for the reaction of 3-phenyl oxazolidinone-2 with succinic and phthalic anhydrides, respectively, fairly agree with earlier values reported for the corresponding reactions of the cyclic carbonates.     

Oxidation of congested thiophene 1,1-dioxides with m-chloroperbenzoic acid. Formation of epoxides and thiete 1,1-dioxides and steric acceleration

A series of thiophene dioxides ( 3 ), including highly congested ones, were synthesized. Their oxidation with m-chloroperbenzoic acid (m-CPBA) was investigated either in the presence or in the absence of Na₂CO₃. The following conclusions were reached. (1) Oxidation in the presence of Na₂CO₃ affords the corresponding epoxides ( 4 ) in moderate to excellent yields. (2) Oxidation in the absence of Na₂CO₃ produces the ring-contracted thiete 1,1-dioxides ( 5 ) as the principal product, thus providing a novel synthesis of the sulfur-containing unsaturated four-membered ring system. If necessary, 5 can also be derived by treatment of 4 with BF₃·Et₂O. In an extreme case, the oxidation of 3,4-di(1-adamantyl)thiophene afforded the corresponding thiete dioxide 5b directly in 78% yield. (3) Oxidation takes place faster with a more congested 3 , probably because of destabilization of the HOMO by steric repulsion between bulky substituents and also owing to relief of steric crowding on going from the ground to the transition state. (4) The formation of 5 from 3 in the absence of Na₂CO₃ can be explained by the occurrence of an acid-catalyzed rearrangement of 4 initially formed. However, a competitive pathway leading directly to 5 may also be operative.     

Detoxification of Organosolv-Pretreated Pine Prehydrolysates with Anion Resin and Cysteine for Butanol Fermentation

Bioconversion of lignocellulose to biofuels suffers from the degradation compounds formed during pretreatment and acid hydrolysis. In order to achieve an efficient biomass to biofuel conversion, detoxification is often required before enzymatic hydrolysis and microbial fermentation. Prehydrolysates from ethanol organosolv-pretreated pine wood were used as substrates in butanol fermentation in this study. Six detoxification approaches were studied and compared, including overliming, anion exchange resin, nonionic resin, laccase, activated carbon, and cysteine. It was observed that detoxification by anion exchange resin was the most effective method. The final butanol yield after anion exchange resin treatment was comparable to the control group, but the fermentation was delayed for 72 h. The addition of Ca(OH)₂ was found to alleviate this delay and improve the fermentation efficiency. The combination of Ca(OH)₂ and anion exchange resin resulted in completion of fermentation within 72 h and acetone–butanol–ethanol (ABE) production of 11.11 g/L, corresponding to a yield of 0.21 g/g sugar. The cysteine detoxification also resulted in good detoxification performance, but promoted fermentation towards acid production (8.90 g/L). The effect of salt on ABE fermentation was assessed and the possible role of Ca(OH)₂ was to remove the salts in the prehydrolysates by precipitation.     

A unique feature of hydrogen recovery in endogenous starch-to-alcohol fermentation of the marine microalga, Chlamydomonas perigranulata

A unicellular marine green alga, Chlamydomonas perigranulata, was demonstrated to synthesize starch through photosynthesis, store it in a cell, and ferment it under anaerobic conditions in the dark to produce ethanol, 2,3-butanediol (butanediol), acetic acid, and carbon dioxide (CO₂). Previous fermentation data of an algal biomass cultivated outdoors in a 50-L tubular photo-bioreactor showed good carbon (C) recovery in the fermentation balance, with a higher ratio to alcohols and, therefore, lower ratio to CO₂ in the C distribution of products than what would be expected from the embden-Myerhof-Parnas pathway. These findings led to a proposed concept for a CO₂-ethanol conversion system (CDECS). The above data were evaluated in terms of hydrogen (H) recovery with the following results: C recovery at 105% was well balanced, although H recovery was as high as 139%, meaning an additional gain of H through fermentation. This finding was reproduced wholly in a set of experiments carried out in the same month of the following year, October, whereas another set of experiments was carried out in the following June provided ordinary fermentation results in terms of C and H recoveries with poor growth. Further analyses of these data revealed that butanediol is equal to ethanol as a product from a putative conversion system from CO₂ to the detected fermentation products, leading to the revision of the CDECS concept to a CO₂-alcohol conversion system (CDACS). The relevance of the CDACS will be discussed in relation to the cultivation conditions employed by chance.     

Theoretical influence of third molecule on reaction channels of weakly bound complex CO2… HF systems

In this investigation, reaction channels of weakly bound complexes CO₂…HF, CO₂…HF…NH₃, CO₂…HF…H₂O and CO₂…HF…CH₃OH systems were established at the B3LYP/6‐311++G(3df,2pd) level, using the Gaussian 98 program. The conformers of syn‐fluoroformic acid or syn‐fluoroformic acid plus a third molecule (NH₃, H₂O, or CH₃OH) were found to be more stable than the conformers of the related anti‐fluoroformic acid or anti‐fluoroformic acid plus a third molecule (NH₃, H₂O, or CH₃OH). However, the weakly bound complexes were found to be more stable than either the related syn‐ and anti‐type fluoroformic acid or the acid plus third molecule (NH₃, H₂O, or CH₃OH) conformers. They decomposed into CO₂ + HF, CO₂ + NH₄F, CO₂ + H₃OF or CO₂ + (CH₃)OH₂F combined molecular systems. The weakly bound complexes have four reaction channels, each of which includes weakly bound complexes and related systems. Moreover, each reaction channel includes two transition state structures. The transition state between the weakly bound complex and anti‐fluoroformic acid type structure (T₁₃) is significantly larger than that of internal rotation (T₂₃) between the syn‐ and anti‐FCO₂H (or FCO₂H…NH₃, FCO₂H…H₂O, or FCO₂H…CH₃OH) structures. However, adding the third molecule NH₃, H₂O, or CH₃OH can significantly reduce the activation energy of T₁₃. The catalytic strengths of the third molecules are predicted to follow the order H₂O < NH₃ < CH₃OH. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006     

Electrooxidation of isotope-labeled ethanol: a FTIRS study

In this work, we investigated some important aspects related to the electrooxidation of isotope-labeled ethanol on Pt. The central point was the effect of the adsorption potential on the formation of CO₂ produced from both alcohol and methyl groups during the electrooxidation of ethanol in acid media. As a way to follow these contributions, we used isotope-labeled ethanol (¹³CH₃CH₂OH) and Fourier transform infrared spectroscopy (FTIRS). The yield of ¹³CO₂ increased with the ethanol adsorption potential. Despite the visualization difficulties due to dipole coupling, ¹³CO was detected, indicating that the formation of ¹³CO₂ follows a mechanism analogous to the one of ¹²CO₂. Dedicated to our friend Professor Francisco Carlos Nart (in memoriam), IQSC-USP, Brazil     

Potentiometric determination of free acidity and uranium in uranyl nitrate solutions using sulfate as complexing agent

In this paper free acid and uranium present together in the range of 0.05–3.0 meq and 20–250 mg, respectively, have been determined by potentiometric titration, using Na₂SO₄ and (NH₄)₂SO₄ complexants and NaOH and Na₂CO₃ as titrants. The results are presented as percentage recovery of free acidity and uranium over the range studied. It has been shown that percentage recovery of free acidity suggests a bias which varied from –5% to +74% at different free acidity and uranium concentrations for the Na₂SO₄–NaOH, Na₂SO₄–Na₂CO₃ and (NH₄)₂SO₄–NaOH complexant — titrant combinations. The percentage recovery of uranium always showed a positive bias which could be up to +8% for extreme free acidity — uranium ratios in the case of Na₂SO₄–Na₂CO₃ complexant — titrant combination. For the other Na₂SO₄–NaOH and (NH₄)₂SO₄–NaOH complexant — titrant combinations a positive bias of up to only +4% has been noticed.     

Specific assay for homoserine and its lactone in Pisum sativum. Preparation of homoserine hydroxamic acid

The existence of homoserine lactone in Pisum sativum seedlings is demonstrated. L-Homoserine lactone reacts with hydroxylamine, at neutral or alkaline pH, to form homoserine hydroxamic acid. Procedures are described for preparing L-homoserine lactone and L-homoserine hydroxamic acid. The hydroxamic acid yields a color with maximum absorbance at 492 nm with Fe³⁺ in 0.25 N HCl. This reaction permitted assay for total homoserine and homoserine lactone. Six-day old Pisum sativum seedlings, with cotyledons removed, were extracted with 90% ethanol. Evaporation of the ethanol and addition of Na₂SO₄ solution and toluene and centrifugation removed protein lipids and esters. After clarification with activated charcoal, homoserine lactone content was estimated by reaction with NH₂OH and Fe³⁺ reagents. For total homoserine, protein precipitation was with 2 N HCl and toluene. Evaporation to dryness at 60 °C under vacuum converted all homoserine to the lactone. The values found for total homoserine (μmols/g, wet weight) and preformed lactone (%) with the various growth media used were as follows: nitrate 87.4 (14.7%), NH₂OH 75.2 (6.3%), water 70.5 (7.9%), urea 56.4 (18.9%). Acetic anhydride added to homoserine hydroxamic acid forms acetohydroxamic acid, which yields a color with maximum absorbance at 505 nm with Fe³⁺. This color reaction is seven times as sensitive as the reaction of Fe³⁺ with homoserine hydroxamic acid itself.