Large Amount Of Acetic Acid Research Articles

Effects of long-term ingestion of difructose anhydride III (DFA III) on intestinal bacteria and bile acid metabolism in humans

Changes in the intestinal microbiota of 10 human subjects with long-term ingestion of 3 g/d difructose anhydride III (DFA III; 4 persons, 2 months; 3 persons, 6 months; and 3 persons, 12 months) were examined by denaturing gradient gel electrophoresis (DGGE). According to the answers to questionnaires, the subjects were divided into two groups (constipated and normal). The DGGE profile was different for every individual and each subject had unique profiles of intestinal microbiota. In the DGGE profiles of constipated subjects, the intensities of bands related to Bacteroides spp. increased. Moreover, the DFA III-assimilating bacteria, Ruminococcus sp. were isolated from subjects who ingested DFA III for 12 months. These strains showed 95% similarity of their 16S rDNA sequences with that of Ruminococcus obeum ATCC 29174(T) (X85101) and produced large amounts of acetic acid. DFA III ingestion for 2 months tended to increase total organic acids in feces, and tended to decrease fecal pH and the secondary bile acid (SBA) ratio in total bile acids. The SBA ratio in total bile acids corresponded to fecal pH. The production of SBA was decreased by low pH in vitro. These results indicated that DFA III ingestion in humans tended to lower intestinal pH, inhibited bile acid 7alpha-dehydroxylation activities and also tended to decrease the SBA ratios in total bile acids. Moreover, as another cause for the decrease in the SBA ratio in total bile acids, it was suggested that the number of bile acid 7alpha-dehydroxylating bacteria were decreased by DFA III ingestion.

Controlling Hydrothermal Reaction Pathways To Improve Acetic Acid Production from Carbohydrate Biomass

A two-step hydrothermal process to improve the production of acetic acid was discussed. The first step was to accelerate the formation of 5-hydroxymethyl-2-furaldehyde (HMF), 2-furaldehyde (2-FA), and lactic acid (LA), and the second step was to further convert the furans (HMF, 2-FA) and LA produced in the first step to acetic acid by oxidation with newly supplied oxygen. The acetic acid obtained by the two-step process had not only a high yield but also better purity. The contribution of two pathways via furans and LA in the two-step process to convert carbohydrates into acetic acid was roughly estimated as 85-90%, and the ratio of the contributions of furans and LA to yield acetic acid was estimated as 2:1. The fact that WO of carbohydrates is not capable of producing a large amount of acetic acid, while the two-step process can enhance the acetic acid yield, can be explained because formic acid is a basic product of direct oxidation of carbohydrate, and acetic acid in WO of carbohydrates may come from the oxidation of dehydration products of aldose.

Methanogenesis in McLean Bog, an Acidic Peat Bog in Upstate New York: Stimulation by H2/CO2 in the Presence of Rifampicin, or by Low Concentrations of Acetate

Acidic peat bog soils produce CH4 and although molecular biological studies have demonstrated the presence of diverse methano-genic populations in them, few studies have sustained methanogenesis by adding the CH4 precursors H2/CO2 or acetate, and few indigenous methanogens have been cultured. McLean Bog is a small (ca. 70 m across), acidic (pH 3.4–4.3) Sphagnum -dominated bog in upstate New York. Although addition of H2/CO2 or 10 mM acetate stimulated methanogenesis in soils from a nearby circumneutral-pH fen, neither of these substrates led to sustained methanogenesis in McLean Bog soil slurries. After a brief period of stimulation by H2/CO2, methanogenesis in McLean Bog soil declined, which could be attributed to buildup of large amounts of acetic acid produced from the H2/CO2 by acetogens. Addition of the antibiotic rifampicin inhibited acetogenesis (carried out by Bacteria) and allowed methanogenesis (carried out by Archaea) to continue. Using rifampicin, we were able to study effects of temperature, pH, and salts on methanogenesis from H2/CO2 in McLean Bog soil samples. The enriched H2/CO2-utilizing methanogens showed an optimum for activity near pH 5, and a temperature optimum near 35°C. Methanogenesis was not stimulated by addition of 10 mM acetate, but it was stimulated by 1 mM acetate, and multiple additions were consumed at increasing rates and nearly stoichiometrically converted to CH4. In conclusion, we have found that both hydrogentrophic and aceticlastic methanogens are present in McLean Bog soils, and that methanogenic activity can be stimulated using H2/CO2 in the presence of rifampicin, or using low concentrations of acetate.

Removal of acetic acid from aqueous solutions containing succinic acid and acetic acid by tri- n-octylamine

Extraction of succinic acid and acetic acid by tri- n-octylamine (TOA) was studied under various pHs of their aqueous solutions. For the extraction of both acids, the loading values decreased with increasing values of pH. In the extraction of acetic acid, the sharp decrease in loading values with increasing pH began at higher values than that of succinic acid extraction due to its higher p K A value. Based on the different extractability for succinic acid and acetic acid with pH, the selective removal of acetic acid from succinic acid and acetic acid aqueous mixture was carried out. After three successive extraction by 0.25 mol kg −1 TOA dissolved in 1-octanol at pH 5.1, the large amount of acetic acid from aqueous acid mixture could be removed.

Effect of Lignin on Acetic Acid Production in Wet Oxidation of Lignocellulosic Wastes

Abstract The role of lignin in acetic acid production in wet oxidation (WO) of lignocellulosic biomass was discussed. It was found that lignin was indirectly attributed to the increase of acetic acid production in WO of lignocellulosic waste. A possible mechanism for this is that decomposition intermediates of lignin would act as a retardant in WO of cellulose, leading to the formation of HMF and 2-FA which are dehydration products from monosaccharides and can produce a large amount of acetic acid by their oxidation.

Estimation of volatile acids in wood and bark

To estimate the volatile acids from soft- and hardwoods a simple method was developed. Since the main part of volatile acids originates from acetyl groups of wood polyoses alkaline hydrolysis was applied, upon acidifying the free acetic acid was liberated and distilled. Acetic acid, with small amounts of other volatile acids, was then estimated by titration and expressed in two manners, as mmol acids per 100 g wood and as percent of acetyl group content. The free acids were also analyzed by high pressure liquid chromatography (HPLC), in order to compare the results obtained titrimetrically and chromatographically. Indeed, as expected, the distillate contains large amount of acetic acid and a small amount of formic acid. The titration method is simple and does not require high cost equipment to be carried out, however it delivers slightly higher results than the HPLC technique. This deviation in the results due to other acids is minute and can be tolerated. The titration method can therefore be recommended to estimate the volatile wood acids conveniently. According to the results hardwoods contain significantly more volatile acids than softwoods. Moreover, bark contains also volatile acids. Though highly acidic, heartwoods of oak and chestnut have less volatile acids than most normal hardwoods. In these woods, apparently, the nonvolatile tannins contribute largely to wood acidity.

Assessment of fermentation results ofHanseniaspora (Kloeckera)strains isolated in Finger Lakes' wineries

Hanseniaspora (Kloeckera) yeast strains were isolated from several Finger Lakes' wineries (New York State, USA), which belonged to species H. uvarum and H. osmophila, and were examined by the ability of fermentation in Chardonnay grape juice and synthetic medium, respectively. One-way analysis of variance (ANOVA), post hoc range tests, and pairwise multiple comparison analysis were used to estimate the glucose, fructose consumption and the ethanol, acetic acid production after fermentation in both media. The strains of H. uvarum formed quite a large amount of acetic acid (average 0.753 g l-1) in the grape juice. The isolated H. osmophila strain (FL392) produced an average amount of 68.06 g l-1 of ethanol in the same medium. The compounds analyzed in synthetic medium for H. uvarum and H. osmophila isolates were observed in lesser amounts than in grape juice.

CONTROLLED PRODUCTION OF CIDER BY INDUCTION OF ALCOHOLIC FERMENTATION AND MALOLACTIC CONVERSION

Characterization experiments involving lactic bacteria allowed a strain of Leuconostoc oenos to be selected in terms of growth capacity at variable pH, temperature, ethanol and sulphite concentrations, malic to lactic conversion yield, acetic acid uptake and dextran production capacity. Cider was produced under controlled conditions where the effect of Kloeckera apiculata yeasts on the development of Saccharomyces cerevisiae and production of major non-volatile compounds influencing end product quality was studied. The apiculate yeast was found to produce large amounts of acetic acid and use the other organic acids; also, it hindered fermentation to a certain extent. A study of the effect of the inoculation time with L oenos as an inducer of malolactic fermentation revealed sequential inoculation of the lactic bacterium once most major sugars in the must had been depleted to be the most favourable. Using yeast cell walls boosted fermentation development, as well as degradation of malic acid and synthesis of succinic and acetic acid.

ヒト大便由来のＣｌｏｓｔｒｉｄｉｕｍ ｂｕｔｙｒｉｃｕｍ‐Ｃｌｏｓｔｒｉｄｉｕｍ ｂｅｉｊｅｒｉｎｃｋｉｉ ｇｒｏｕｐならびに嫌気性腸内細菌によるペクチン酸の資化

The Clostridium butyricum-Clostridium beijerinckii group, which was isolated from human feces, assimilated pectic acid and 4, 5-unsaturated digalacturonic acid. Acetic acid and small amounts of n-butyric acid and formic acid were produced from pectic acid, and acetic acid and formic acid were produced from 4, 5-unsaturated digalacturonic acid. Pectic acid was degraded to acetic acid via 4, 5-unsaturated digalacturonic acid. Little galacturonic acid was used as a carbon source by this bacterium and alginic acid was not used. The other anaerobic intestinal bacteria tested produced a large amount of acetic acid and small amount of n-butyric acid from pectic acid, and the acetic acid produced was 35-42% carbon equivalents.

A balanced DO‐stat and its application to the control of acetic acid excretion by recombinant Escherichia coli

During fed-batch cultivation of a recombinant Escherichia coli AT2471 harboring plasmid pSY130-14 for phenylalanine production, a large amount of acetic acid was excreted by the cells and accumulated in the culture medium. Acetic acid concentration reached 30-35 g/L at the end of a process conducted without special precautions for the reduction of this excretion. Cell growth stopped when acetic acid concentration was about 15 g/L, resulting in poor growth, 16 g/L cell concentration, and poor production - 8 g/L phenylalanine. A novel control strategy, called a balanced DO-stat. was developed to prevent acetic acid excretion. It represents a model-independent two-loop control structure, which is simple, reliable, and convenient for computer application. Using the balanced DO-stat, implemented in a computer control system, acetic acid concentration was kept at zero during the entire cultivation period. As a result, the cell concentration increased to 36 g/L and phenylalanine concentration reached 24 g/L. Aside from the phenylalanine fermentation, the proposed control approach might be applied to cultivation of other bacterial and yeast strains which have similar mechanism of the excretion of fermentative by-products.

Physicochemical characteristics and flora of diarrhoeal and recovery faeces in children with acute gastroenteritis in Kenya

Physiochemical characteristics and flora of diarrhoeal and recovery faeces were investigated in 14 Kenyan children with acute gastro-enteritis. Causative micro-organisms were Shigella, Campylobacter, enterotoxigenic Escherichia coli, rotavirus and unknown in 6, 2, 1, 2 and 3 patients, respectively. The mean values of the pH of the diarrhoeal specimens were significantly higher than those of the recovery specimens. Large amounts of acetic acid and many other kinds of fatty acids were detected in the recovery specimens, but small amounts and few kinds of fatty acids were detected in the diarrhoeal specimens. Bacterial counts of anaerobic organisms, such as Bacteroides, Bifidobacterium, Lactobacillus and Eubacterium, were lower in the diarrhoeal specimens than in the recovery ones. The normal anaerobic intestinal flora is remarkably disturbed in patients with acute gastro-enteritis. This may result in changes in fatty acid contents and in the pH of diarrhoeal faeces.

Regulating Flavor Compound Synthesis and Cofactor Recycling in Heterogeneous Enzymatic Reactions by Mixtures of Bacterial Cell-Free Extracts

Enzymatic cofactor recycling and generation of acetic acid, 3-methylbutanal, and 3-methylbutanol were evaluated using a mixture of cell-free extracts of Gluconobacter oxydans and Streptococcus lactis var. maltigenes. Ethanol was used as a substrate by cell-free extracts of G, oxydans to produce acetic acid and to generate reduced nicotinamide adenine dinucleotide from nicotinamide adenine dinucleotide. Leucine was converted by S. lactis var. maltigenes cell-free extracts to 3-methylbutanal and 3-methylbutanol and to regenerate nicotinamide adenine dinucleotides. Optimum pH to form 3-methylbutanal by the combined cell-free extracts was about 6.8 and that for 3-methylbutanol was 6.4. At 30°C, 3-methylbutanol reached a maximum of 73ppm after 30h but declined slightly at 48h. Concentrations of 3-methylbutanol increased gradually over 48h to a maximum of 56ppm. Rates of production of these compounds at 12.8°C were about half that at 32°C. Concentrations of 3-methylbutanol were increased to about those of 3-methylbutanal by adjusting the concentrations of substrate, nicotinamide adenine dinucleotide, cell-free extract, and pH so as to produce large amounts of acetic acid and reduced nicotinamide adenine dinucleotide.

ChemInform Abstract: SYNTHESIS OF ACETIC ANHYDRIDE BY VAPOR PHASE CARBONYLATION OF METHYL ACETATE WITH A NICKEL‐ACTIVE CARBON CATALYST

AbstractEssigsäuremethylester (I) reagiert in Gegenwart von Methyliodid (III) und Nickel(II)‐acetat (IV) mit Kohlenmonoxid (II) zu einem Gemisch aus Acetanhydrid (V), Essigsäure (VI) und Methan (VII).

Vapor phase carbonylation of dimethyl ether and methyl acetate with nickel-active carbon catalysts

Vapor phase carbonylation of dimethyl ether and methyl acetate on nickel-active carbon catalysts was studied under pressurized conditions in the presence of methyl iodide as a promoter. Methyl acetate was synthesized from dimethyl ether and carbon monoxide with a selectivity of 80 to 90% at 250° C and 11 atm. A small amount of acetic anhydride was obtained at higher pressure which was essential for the acetic anhydride formation from methyl acetate. By-products such as acetic acid, methane and carbon dioxide were formed in both reactions. In particular, fairly large amount of acetic acid was formed in spite of the reaction under water free condition to bring about the decrease in the selectivity to acetic anhydride.

SYNTHESIS OF ACETIC ANHYDRIDE BY VAPOR PHASE CARBONYLATION OF METHYL ACETATE WITH A NICKEL-ACTIVE CARBON CATALYST

Abstract Vapor phase carbonylation of methyl acetate on nickel-active carbon catalyst was studied under pressurized conditions in the presence of methyl iodide as a promoter. High pressure was essential for the acetic anhydride formation. A fairly large amount of acetic acid, by-product, was also formed under the water-free reaction condition.

Urinary bacteria: potential source of some organic acidurias

Normal human urine was inoculated with pure cultures of various urinary pathogens, and then incubated at 37°. Organic acids were measured in the urine by gas Chromatographie techniques. Microorganisms of 11different species were found capable of producing large amounts of acetic acid in urine, while 8 species produced propionic acid. Bacteria of 8 different species were able to hydrolyze hippuric acid to benzoic acid. A few organisms also produced butyric, isovaleric, or caproic acid. Thus investigators who study cases of presumed metabolic disorders in man must exclude the possibility that abnormal acids found in urine are only artifacts produced by urinary tract infections.

Causative Bacteria of Flat Souring Deterioration of Fish Sausage

Bacteriological studies have been conducted on the flat souring deterioration of fish sausage.The spoiled sample showed pH down and a large amount of acetic acid and formic acid were detected in them. At the same time, viable bacteria was found at the level of about 104 per gram. The isolated strain was identified to be Bacillus coagulans which is known as the causative bacteria of flat souring of canned milk products and tomato products.

Production of acetic acid and other volatile compounds by Leucoostoc citrovorum and Leuconostoc dextranicum.

Single-strain milk cultures of Leuconostoc dextranicum are capable of reducing added acetaldehyde, propionaldehyde, and butanone to the corresponding alcohols at 30 C. L. dextranicum and L. citrovorum reduced propionaldehyde to n-propanol quantitatively in 30 hr, and the reduction of this compound paralleled culture growth. Under unagitated conditions, these organisms produced large amounts of acetic acid and ethyl alcohol. The yield of acetic acid increased when cultures were agitated during growth. This increase in acetic acid production was accompanied by a 20- to 70-fold decrease in ethyl alcohol. The addition of acetaldehyde to the fermentation caused a reduction in the final concentration of acetic acid.

Production of Acetic Acid and Other Volatile Compounds by Leuconostoc citrovorum and Leuconostoc dextranicum1

Single-strain milk cultures of Leuconostoc dextranicum are capable of reducing added acetaldehyde, propionaldehyde, and butanone to the corresponding alcohols at 30 C. L. dextranicum and L. citrovorum reduced propionaldehyde to n-propanol quantitatively in 30 hr, and the reduction of this compound paralleled culture growth. Under unagitated conditions, these organisms produced large amounts of acetic acid and ethyl alcohol. The yield of acetic acid increased when cultures were agitated during growth. This increase in acetic acid production was accompanied by a 20- to 70-fold decrease in ethyl alcohol. The addition of acetaldehyde to the fermentation caused a reduction in the final concentration of acetic acid.

The heterometric microdetermination of mercury of mercaptobenzthiazole

The heterometric determinations of murcury or mercaptobentlnazole are very sensitive reactions. An aqueous or a dilute alcoholic solution is used and the titration may lie carried out at pH 2–10. If meicaptobenzlhiazole is determined, two analytical end-points are obtained : the first gives an estimate, the second gives the precise end-point. In all cases, the insoluble Hg(MBT) 2 is obtained, The presence of larger amounts of strong acids is disadvantageous Large amounts of acetic acid cause distuibances in aqueous solution; dilute alcoholic .solution is therefore used The theoretical end-point is obtained by the intersection of two lines. In acid solution a horizontal maximum density line is obtained at the end ot the reaction, in alkahne solution a maximum point is obtained instead. 1–2 mg mercury or meicaptobenzthiazole may be determined in 20–30 ml solution with an error of 0–3% 'Ihe titration time is 10–20 mniutes