A product of fermentation. It is a component of the butanediol cycle in microorganisms. In mammals it is oxidized to carbon dioxide.
An enzyme that catalyzes the conversion of acetoin to diacetyl in the presence of NAD.
Butanones, also known as methyl ethyl ketone or MEK, are organic compounds consisting of a four-carbon chain with a ketone functional group located at the second carbon atom, classified as dimethyl ketones, and commonly used in industrial and laboratory settings as solvents and chemical intermediates.
4-carbon straight chain aliphatic hydrocarbons substituted with two hydroxyl groups. The hydroxyl groups cannot be on the same carbon atom.
Carrier of aroma of butter, vinegar, coffee, and other foods.
A genus of gram-positive, facultatively anaerobic bacteria whose growth is dependent on the presence of a fermentable carbohydrate. It is nonpathogenic to plants and animals, including humans.
Anaerobic degradation of GLUCOSE or other organic nutrients to gain energy in the form of ATP. End products vary depending on organisms, substrates, and enzymatic pathways. Common fermentation products include ETHANOL and LACTIC ACID.
A colorless, flammable liquid used in the manufacture of acetic acid, perfumes, and flavors. It is also an intermediate in the metabolism of alcohol. It has a general narcotic action and also causes irritation of mucous membranes. Large doses may cause death from respiratory paralysis.
A subclass of enzymes which includes all dehydrogenases acting on primary and secondary alcohols as well as hemiacetals. They are further classified according to the acceptor which can be NAD+ or NADP+ (subclass 1.1.1), cytochrome (1.1.2), oxygen (1.1.3), quinone (1.1.5), or another acceptor (1.1.99).

Biochemical and molecular characterization of the Bacillus subtilis acetoin catabolic pathway. (1/91)

A recent study indicated that Bacillus subtilis catabolizes acetoin by enzymes encoded by the acu gene cluster (F. J. Grundy, D. A. Waters, T. Y. Takova, and T. M. Henkin, Mol. Microbiol. 10:259-271, 1993) that are completely different from those in the multicomponent acetoin dehydrogenase enzyme system (AoDH ES) encoded by aco gene clusters found before in all other bacteria capable of utilizing acetoin as the sole carbon source for growth. By hybridization with a DNA probe covering acoA and acoB of the AoDH ES from Clostridium magnum, genomic fragments from B. subtilis harboring acoA, acoB, acoC, acoL, and acoR homologous genes were identified, and some of them were functionally expressed in E. coli. Furthermore, acoA was inactivated in B. subtilis by disruptive mutagenesis; these mutants were impaired to express PPi-dependent AoDH E1 activity to remove acetoin from the medium and to grow with acetoin as the carbon source. Therefore, acetoin is catabolized in B. subtilis by the same mechanism as all other bacteria investigated so far, leaving the function of the previously described acu genes obscure.  (+info)

Three distinct phases of isoprene formation during growth and sporulation of Bacillus subtilis. (2/91)

During growth on a glucose-tryptone medium, Bacillus subtilis 6051 (Marburg strain) exhibited three phases of isoprene (2-methyl-1, 3-butadiene) formation, corresponding to (i) glucose catabolism and secretion of acetoin, (ii) catabolism of acetoin, and (iii) the early stages of sporulation. These results establish an experimental system for studying the biological role of isoprene formation.  (+info)

Characterization of a (2R,3R)-2,3-butanediol dehydrogenase as the Saccharomyces cerevisiae YAL060W gene product. Disruption and induction of the gene. (3/91)

The completion of the Saccharomyces cerevisiae genome project in 1996 showed that almost 60% of the potential open reading frames of the genome had no experimentally determined function. Using a conserved sequence motif present in the zinc-containing medium-chain alcohol dehydrogenases, we found several potential alcohol dehydrogenase genes with no defined function. One of these, YAL060W, was overexpressed using a multicopy inducible vector, and its protein product was purified to homogeneity. The enzyme was found to be a homodimer that, in the presence of NAD(+), but not of NADP, could catalyze the stereospecific oxidation of (2R,3R)-2, 3-butanediol (K(m) = 14 mm, k(cat) = 78,000 min(-)(1)) and meso-butanediol (K(m) = 65 mm, k(cat) = 46,000 min(-)(1)) to (3R)-acetoin and (3S)-acetoin, respectively. It was unable, however, to further oxidize these acetoins to diacetyl. In the presence of NADH, it could catalyze the stereospecific reduction of racemic acetoin ((3R/3S)- acetoin; K(m) = 4.5 mm, k(cat) = 98,000 min(-)(1)) to (2R,3R)-2,3-butanediol and meso-butanediol, respectively. The substrate stereospecificity was determined by analysis of products by gas-liquid chromatography. The YAL060W gene product can therefore be classified as an NAD-dependent (2R,3R)-2,3-butanediol dehydrogenase (BDH). S. cerevisiae could grow on 2,3-butanediol as the sole carbon and energy source. Under these conditions, a 3. 5-fold increase in (2R,3R)-2,3-butanediol dehydrogenase activity was observed in the total cell extracts. The isoelectric focusing pattern of the induced enzyme coincided with that of the pure BDH (pI 6.9). The disruption of the YAL060W gene was not lethal for the yeast under laboratory conditions. The disrupted strain could also grow on 2,3-butanediol, although attaining a lesser cell density than the wild-type strain. Taking into consideration the substrate specificity of the YAL060W gene product, we propose the name of BDH for this gene. The corresponding enzyme is the first eukaryotic (2R, 3R)-2,3-butanediol dehydrogenase characterized of the medium-chain dehydrogenase/reductase family.  (+info)

An operon for a putative ATP-binding cassette transport system involved in acetoin utilization of Bacillus subtilis. (4/91)

The ytrABCDEF operon of Bacillus subtilis was deduced to encode a putative ATP-binding cassette (ABC) transport system. YtrB and YtrE could be the ABC subunits, and YtrC and YtrD are highly hydrophobic and could form a channel through the cell membrane, while YtrF could be a periplasmic lipoprotein for substrate binding. Expression of the operon was examined in cells grown in a minimal medium. The results indicate that the expression was induced only early in the stationary phase. The six ytr genes form a single operon, transcribed from a putative sigma(A)-dependent promoter present upstream of ytrA. YtrA, which possesses a helix-turn-helix motif of the GntR family, acts probably as a repressor and regulates its own transcription. Inactivation of the operon led to a decrease in maximum cell yield and less-efficient sporulation, suggesting its involvement in the growth in stationary phase and sporulation. It is known that B. subtilis produces acetoin as an external carbon storage compound and then reuses it later during stationary phase and sporulation. When either the entire ytr operon or its last gene, ytrF, was inactivated, the production of acetoin was not affected, but the reuse of acetoin became less efficient. We suggest that the Ytr transport system plays a role in acetoin utilization during stationary phase and sporulation.  (+info)

Bacillus subtilis ccpA gene mutants specifically defective in activation of acetoin biosynthesis. (5/91)

A large number of carbon source utilization pathways are repressed in Bacillus subtilis by the global regulator CcpA, which also acts as an activator of carbon excretion pathways during growth in media containing glucose. In this study, CcpA mutants defective in transcriptional activation of the alsSD operon, which is involved in acetoin biosynthesis, were identified. These mutants retained normal glucose repression of amyE, encoding alpha-amylase, and acsA, encoding acetyl-coenzyme A synthetase, and normal activation of ackA, which is involved in acetate excretion; in these ccpA mutants the CcpA functions of activation of the acetate and acetoin excretion pathways appear to be separated.  (+info)

Analysis of acetoin and diacetyl in bacterial culture supernatants by gas-liquid chromatography. (6/91)

The acetoin and diacetyl contents of culture supernatants of Voges-Proskauer-positive "viridans" streptotocci, Klebsiella pneumoniae and Staphylococcus aureus, were determined by a gas liquid chromatographic procedure, in which supernatants were extracted with diethyl ether and diacetyl was measured on columns of 10% (wt/wt) polyethylene glycol 400 (PEG 400) at 73 C. Acetoin was converted to diacetyl, before analysis, by a simple oxidation procedure with ferric chloride and without a distillation step. Streptococcal culture supernatants were shown by this method to contain only acetoin; supernatants of K. pneumoniae and S. aureus contained both acetoin and diacetyl.  (+info)

Mutagenesis at asp27 of pyruvate decarboxylase from Zymomonas mobilis. Effect on its ability to form acetoin and acetolactate. (7/91)

Pyruvate decarboxylase (PDC) is one of several enzymes that require thiamin diphosphate (ThDP) and a bivalent cation as essential cofactors. The three-dimensional structure of PDC from Zymomonas mobilis (ZMPDC) shows that Asp27 (D27) is close to ThDP in the active site, and mutagenesis of this residue has suggested that it participates in catalysis. The normal product of the PDC reaction is acetaldehyde but it is known that the enzyme can also form acetoin as a by-product from the hydroxyethyl-ThDP reaction intermediate. This study focuses on the role of D27 in the production of acetoin and a second by-product, acetolactate. D27 in ZMPDC was altered to alanine (D27A) and this mutated protein, the wild-type, and two other previously constructed PDC mutants (D27E and D27N) were expressed and purified. Determination of the kinetic properties of D27A showed that the affinity of D27A for ThDP is decreased 30-fold, while the affinity for Mg2+ and the Michaelis constant for pyruvate were similar to those of the wild-type. The time-courses of their reactions were investigated. Each mutant has greatly reduced ability to produce acetaldehyde and acetoin compared with the wild-type PDC. However, the effect of these mutations on acetaldehyde production is greater than that on acetoin formation. The D27A mutant can also form acetolactate, whereas neither of the other mutants, nor the wild-type PDC, can do so. In addition, acetaldehyde formation and/or release are reversible in wild-type ZMPDC but irreversible for the mutants. The results are explained by a mechanism involving thermodynamic and geometric characteristics of the intermediates in the reaction.  (+info)

Regulation of the acetoin catabolic pathway is controlled by sigma L in Bacillus subtilis. (8/91)

Bacillus subtilis grown in media containing amino acids or glucose secretes acetate, pyruvate, and large quantities of acetoin into the growth medium. Acetoin can be reused by the bacteria during stationary phase when other carbon sources have been depleted. The acoABCL operon encodes the E1alpha, E1beta, E2, and E3 subunits of the acetoin dehydrogenase complex in B. subtilis. Expression of this operon is induced by acetoin and repressed by glucose in the growth medium. The acoR gene is located downstream from the acoABCL operon and encodes a positive regulator which stimulates the transcription of the operon. The product of acoR has similarities to transcriptional activators of sigma 54-dependent promoters. The four genes of the operon are transcribed from a -12, -24 promoter, and transcription is abolished in acoR and sigL mutants. Deletion analysis showed that DNA sequences more than 85 bp upstream from the transcriptional start site are necessary for full induction of the operon. These upstream activating sequences are probably the targets of AcoR. Analysis of an acoR'-'lacZ strain of B. subtilis showed that the expression of acoR is not induced by acetoin and is repressed by the presence of glucose in the growth medium. Transcription of acoR is also negatively controlled by CcpA, a global regulator of carbon catabolite repression. A specific interaction of CcpA in the upstream region of acoR was demonstrated by DNase I footprinting experiments, suggesting that repression of transcription of acoR is mediated by the binding of CcpA to the promoter region of acoR.  (+info)

Acetoin is a chemical compound that is produced as a metabolic byproduct in certain types of bacteria, including some species of streptococcus and lactobacillus. It is a colorless liquid with a sweet, buttery odor and is used as a flavoring agent in the food industry. In addition to its use as a flavoring, acetoin has been studied for its potential antibacterial properties and its possible role in the development of biofilms. However, more research is needed to fully understand the potential uses and implications of this compound.

Acetoin dehydrogenase is an enzyme complex that plays a role in the metabolism of certain organic compounds. It is responsible for catalyzing the oxidation of acetoin to diacetyl, which is then further oxidized to acetate. This enzyme complex is found in many different types of bacteria and is involved in their energy metabolism. Acetoin dehydrogenase is a multi-enzyme complex that consists of several different subunits, including an acetoin reductase, a diacetyl reductase, and a dihydrolipoyl dehydrogenase. These subunits work together to catalyze the oxidation of acetoin in a series of steps. The overall reaction is:

Acetoin + NAD+ -> Diacetyl + NADH + H+

Diacetyl + 2NADH + 2H+ -> 2Acetate + 2NAD+

The overall equation for the conversion of acetoin to acetate by acetoin dehydrogenase is:

Acetoin + NAD+ -> 2Acetate + NADH + H+

This reaction is important in the metabolism of certain types of bacteria, as it allows them to generate energy and reduce power for their growth and survival.

Butanones are a group of chemical compounds that contain a ketone functional group and have the molecular formula C4H8O. They are also known as methyl ethyl ketones or MEKs. The simplest butanone is called methyl ethyl ketone (MEK) or 2-butanone, which has a chain of four carbon atoms with a ketone group in the second position. Other butanones include diethyl ketone (3-pentanone), which has a ketone group in the third position, and methyl isobutyl ketone (MIBK) or 4-methyl-2-pentanone, which has a branched chain with a ketone group in the second position.

Butanones are commonly used as solvents in various industrial applications, such as paint thinners, adhesives, and cleaning agents. They have a characteristic odor and can be harmful if ingested or inhaled in large quantities. Exposure to butanones can cause irritation of the eyes, skin, and respiratory tract, and prolonged exposure may lead to neurological symptoms such as dizziness, headache, and nausea.

Butylene glycols are a type of organic compounds that belong to the class of diols, which are chemical compounds containing two hydroxyl groups. Specifically, butylene glycols are composed of a four-carbon chain with two hydroxyl groups located on adjacent carbon atoms.

There are two isomeric forms of butylene glycol: 1,2-butanediol and 1,3-butanediol.

* 1,2-Butanediol (also known as 1,2-butylene glycol) has the hydroxyl groups on the first and second carbon atoms of the chain. It is a colorless, viscous liquid that is used as a solvent, humectant, and antifreeze in various industrial and cosmetic applications.
* 1,3-Butanediol (also known as 1,3-butylene glycol) has the hydroxyl groups on the first and third carbon atoms of the chain. It is also a colorless, viscous liquid that is used as a solvent, humectant, and antifreeze in various industrial and cosmetic applications.

Butylene glycols are generally considered to be safe for use in cosmetics and other consumer products, although they may cause skin irritation or allergic reactions in some individuals. They are also used as intermediates in the synthesis of other chemicals, such as polyesters and polyurethanes.

Diacetyl is a volatile, yellow-green liquid that is a byproduct of fermentation and is used as a butter flavoring in foods. The chemical formula for diacetyl is CH3COCH3. It has a buttery or creamy taste and is often added to microwave popcorn, margarine, and other processed foods to give them a buttery flavor.

Diacetyl can also be found in some alcoholic beverages, such as beer and wine, where it is produced naturally during fermentation. In high concentrations, diacetyl can have a strong, unpleasant odor and taste.

There has been concern about the potential health effects of diacetyl, particularly for workers in factories that manufacture artificial butter flavorings. Some studies have suggested that exposure to diacetyl may increase the risk of developing lung disease, including bronchiolitis obliterans, a serious and sometimes fatal condition characterized by scarring and narrowing of the airways in the lungs. However, more research is needed to fully understand the health effects of diacetyl and to determine safe levels of exposure.

Leuconostoc is a genus of gram-positive, facultatively anaerobic bacteria that belong to the family Leuconostocaceae. These bacteria are non-motile, non-spore forming, and occur as pairs or chains. They are catalase-negative and reduce nitrate to nitrite.

Leuconostoc species are commonly found in nature, particularly in plants, dairy products, and fermented foods. They play a significant role in the food industry, where they are used in the production of various fermented foods such as sauerkraut, pickles, and certain cheeses.

In clinical settings, Leuconostoc species can sometimes be associated with healthcare-associated infections, particularly in patients who have underlying medical conditions or who are immunocompromised. They can cause bacteremia, endocarditis, and device-related infections. However, these infections are relatively rare, and the majority of Leuconostoc species are considered to be non-pathogenic.

Fermentation is a metabolic process in which an organism converts carbohydrates into alcohol or organic acids using enzymes. In the absence of oxygen, certain bacteria, yeasts, and fungi convert sugars into carbon dioxide, hydrogen, and various end products, such as alcohol, lactic acid, or acetic acid. This process is commonly used in food production, such as in making bread, wine, and beer, as well as in industrial applications for the production of biofuels and chemicals.

Acetaldehyde is a colorless, volatile, and flammable liquid with a pungent odor. It is the simplest aldehyde, with the formula CH3CHO. Acetaldehyde is an important intermediate in the metabolism of alcohol and is produced by the oxidation of ethanol by alcohol dehydrogenase. It is also a naturally occurring compound that is found in small amounts in various foods and beverages, such as fruits, vegetables, and coffee.

Acetaldehyde is a toxic substance that can cause a range of adverse health effects, including irritation of the eyes, nose, and throat, nausea, vomiting, and headaches. It has been classified as a probable human carcinogen by the International Agency for Research on Cancer (IARC). Long-term exposure to acetaldehyde has been linked to an increased risk of certain types of cancer, including cancers of the oral cavity, esophagus, and liver.

Alcohol oxidoreductases are a class of enzymes that catalyze the oxidation of alcohols to aldehydes or ketones, while reducing nicotinamide adenine dinucleotide (NAD+) to NADH. These enzymes play an important role in the metabolism of alcohols and other organic compounds in living organisms.

The most well-known example of an alcohol oxidoreductase is alcohol dehydrogenase (ADH), which is responsible for the oxidation of ethanol to acetaldehyde in the liver during the metabolism of alcoholic beverages. Other examples include aldehyde dehydrogenases (ALDH) and sorbitol dehydrogenase (SDH).

These enzymes are important targets for the development of drugs used to treat alcohol use disorder, as inhibiting their activity can help to reduce the rate of ethanol metabolism and the severity of its effects on the body.

In some bacteria, acetoin can also be reduced to 2,3-butanediol by acetoin reductase/2,3-butanediol dehydrogenase. The Voges- ... The form produced by bacteria is (R)-acetoin. Acetoin is a neutral, four-carbon molecule used as an external energy store by a ... The conversion of acetoin into acetyl-CoA is catalysed by the acetoin dehydrogenase complex, following a mechanism largely ... Proskauer test is a commonly used microbiological test for acetoin production. Acetoin, along with diacetyl, is one of the ...
... (EC 2.3.1.190, acetoin dehydrogenase complex, acetoin dehydrogenase enzyme system, AoDH ES) is an enzyme ... Acetoin+dehydrogenase at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Portal: Biology (Articles with ... This enzyme catalyses the following chemical reaction acetoin + CoA + NAD+ ⇌ {\displaystyle \rightleftharpoons } acetaldehyde ... "Identification and molecular characterization of the Alcaligenes eutrophus H16 aco operon genes involved in acetoin catabolism ...
... (EC 1.1.1.304, (S)-acetoin dehydrogenase) is an enzyme with systematic name (S)- ... acetoin:NAD+ oxidoreductase. This enzyme catalyses the following chemical reaction (S)-acetoin + NAD+ ⇌ {\displaystyle \ ... Different from EC 1.1.1.303, diacetyl reductase ((R)-acetoin forming). Giovannini, P.P.; Medici, A.; Bergamini, C.M.; Rippa, M ... acetoin) reductase from Enterobacter aerogenes". Eur. J. Biochem. 198 (2): 327-332. doi:10.1111/j.1432-1033.1991.tb16019.x. ...
In enzymology, an acetoin-ribose-5-phosphate transaldolase (EC 2.2.1.4) is an enzyme that catalyzes the chemical reaction 3- ... from DL-acetoin and D-ribose 5-phosphate by a transketolase mutant of Bacillus pumilus". Agric. Biol. Chem. 47 (7): 1545-1553. ...
... (EC 1.1.1.303, (R)-acetoin dehydrogenase) is an enzyme with systematic name (R)- ... acetoin:NAD+ oxidoreductase. This enzyme catalyses the following chemical reaction (R)-acetoin + NAD+ ⇌ {\displaystyle \ ... This enzyme is different from EC 1.1.1.304, diacetyl reductase ((S)-acetoin forming). Heidlas J, Tressl R (1990). "Purification ...
Acetoin is an intermediate. Diacetyl and acetoin are two compounds that give butter its characteristic taste. Because of this, ... The yeast then absorbs the diacetyl, and reduces the ketone groups to form acetoin and 2,3-butanediol.[citation needed] Beer ... Acetylpropionyl, a similar diketone Acetoin Bronchiolitis obliterans Merck Index (11th ed.). p. 2946. Eriks K, Hayden TD, Yang ... manufacturers of artificial butter flavoring, margarines or similar oil-based products typically add diacetyl and acetoin ( ...
Diacetyl, a similar diketone Acetoin "2,3-Pentanedione". Hardo Siegel, Manfred Eggersdorfer "Ketones" in Ullmann's Encyclopedia ...
Krampitz, L.O. (1957). [50] Preparation and determination of acetoin, diacetyl, and acetolactate. Methods in Enzymology. Vol. 3 ...
Bertagnolli BL, Hager LP (January 1993). "Role of flavin in acetoin production by two bacterial pyruvate oxidases". Archives of ...
Diacetyl, acetoin, and 2,3-pentanedione are used for buttery flavoring. Camphor and cyclohexanone are used for minty flavoring ... acetoin, 2,3-pentanedione, cyclohexanone, benzaldehyde, cresol, butyraldehyde, and isoamyl acetate. Sugars are frequently used ...
It produces H2S from thiosulfate but does not produce acetoin or indole. It's catalase and cytochrome oxidase positive with no ...
Geckil H, Barak Z, Chipman DM, Erenler SO, Webster DA, Stark BC (October 2004). "Enhanced production of acetoin and butanediol ... "Thermophilic fermentation of acetoin and 2,3-butanediol by a novel Geobacillus strain". Biotechnology for Biofuels. 5 (1): 88. ...
α-Acetolactic acid can also be decarboxylated by alpha-acetolactate decarboxylase to produce acetoin. The name α-acetolactate ...
... is a species of bacteria that ferments 2,3-butanediol and acetoin. It is Gram-negative, strictly ...
... is a species of bacteria that ferments 2,3-butanediol and acetoin. It is Gram-negative, strictly ...
It also tests positive for acetoin production, arginine, dihydrolase, benzidine, catalase, hemolysis, and lipase; it tests ...
Gabriel, M. A.; Ilbawi, M.; Al-Khalidi, U. A. S. (1972-03-15). "The oxidation of acetoin to CO2 in intact animals and in liver ... Specifically, he researched riboflavin biosynthesis, acetoin metabolism in mammals, acetyl-coA metabolism in liver supernatant ...
Together with the acetylpolyamine amidohydrolases and the acetoin utilization proteins, the histone deacetylases form an ... Leipe DD, Landsman D (September 1997). "Histone deacetylases, acetoin utilization proteins and acetylpolyamine amidohydrolases ... as HDAC homologs have been found in bacteria in the form of Acetoin utilization proteins (AcuC) proteins. Within the Class I ...
Members of this group are esculin positive, 6.5% salt negative, sorbitol negative and produce acetoin. Isolates from the S. ...
Acetoin and Diacetyl by Wine Making Lactic Acid Bacteria". Agricultural and Biological Chemistry. 49 (7): 2147-2157. doi: ...
Tolasch, Till; Sölter, Susanne; Tóth, Miklós; Ruther, Joachim; Francke, Wittko (2003-04-01). "(R)-Acetoin-Female Sex Pheromone ...
The yeasts also help keep levels low by consuming diacetyl and reducing it to acetoin and butylene glycol. Diacetyl production ... The main products of malolactic fermentation are lactic acid, diacetyl, acetic acid, acetoin, and various esters. The amount ... Acetoin and Diacetyl by Wine Making Lactic Acid Bacteria" Agricultural and Biological Chemistry 49(7), 2147-2157, 1985 Jan ...
Acetoin is produced by several species and is further reduced to 2,3-butanediol by Clostridium beijerinckii. Clostridium ...
That notice also solicited input regarding exposure and health effects of acetoin, acetaldehyde, acetic acid and furfural. Two ... It may contain diacetyl, acetylpropionyl, or acetoin, three natural compounds in butter that contribute to its characteristic ...
Tests used to identify S. pseudintermedius specifically include DNase, hyaluronidase, coagulase, catalase, and acetoin ...
Like members of the S. mitis group, they are negative for acetoin production and mannitol and sorbitol fermentation. The S. ... S. salivarius group organisms are positive for acetoin production and are esculin positive but are negative for arginine ... Isolates in this group are negative for acetoin production, arginine, esculin, and mannitol and are sorbitol fermentation ... They do not hydrolyze arginine but are positive for acetoin production, esculin hydrolysis, and mannitol and sorbitol ...
The Voges-Proskauer test detects whether a bacterium is producing the product acetoin from the digestion of glucose. Mycolic ...
It does not produce indole or acetoin, with the latter characteristic representing a negative Voges-Proskauer test result. It ...
This strain grows best between 18 and 25°C.This strain can ferment citrate into acetoin and diacetyl. Most strains of this ...
Other names in common use include L-butanediol dehydrogenase, L-BDH, and L(+)-2,3-butanediol dehydrogenase (L-acetoin forming ... acetoin + NADH + H+ Thus, the two substrates of this enzyme are (S,S)-butane-2,3-diol and NAD+, whereas its 3 products are ... acetoin, NADH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of ...
In some bacteria, acetoin can also be reduced to 2,3-butanediol by acetoin reductase/2,3-butanediol dehydrogenase. The Voges- ... The form produced by bacteria is (R)-acetoin. Acetoin is a neutral, four-carbon molecule used as an external energy store by a ... The conversion of acetoin into acetyl-CoA is catalysed by the acetoin dehydrogenase complex, following a mechanism largely ... Proskauer test is a commonly used microbiological test for acetoin production. Acetoin, along with diacetyl, is one of the ...
Sulfurol, tetramethylpyrazine ,Acetoin,2,3-Dimethyl,pyrazine,4-Methyl-5-vinylthiazole ...
Acetoin. -. -. Optochin disk. Resistant. ND. Enzymes. α-galactosidase. +. +. β-galactosidase. Variable. +. β-glucuronidase. +. ...
ACETOIN BUTYRATE. Fruity, Sweet. ACETONE. Pungent, solvent, apple, pear, fruity. ACETONE Liquid. Pungent, solvent, apple, pear ...
Sampling and analytical methods: acetoin and diacetyl. Washington, DC: US Department of Labor, Occupational Safety and Health ...
... three constitutive and two inducible promoters to drive the expression of two fluorescent reporter proteins and a short acetoin ... three constitutive and two inducible promoters to drive the expression of two fluorescent reporter proteins and a short acetoin ... Acetoin production pathway comprising the C83S ilvB mutant from E. coli and aldB from Brevibacillus brevis (A); acetoin titers ... Employing the optimized gene expression architecture to the acetoin pathway led to an acetoin accumulation of 5.5 ± 0.76 mM, ...
acetoin. 180.00. isoamyl valerate. 40.00. benzaldehyde. 10.00. ethyl phenyl acetate. 10.00. aldehyde C-18. ...
meso-2,3-BD and (2R,3R)-2,3-BD were transformed from racemic acetoin by meso-BDH and GDH with NADH, respectively. Compared with ... meso-2,3-BD and (2R,3R)-2,3-BD were transformed from racemic acetoin by meso-BDH and GDH with NADH, respectively. ... Xiao Z, Wang X, Huang Y, Huo F, Zhu X, Xi L, Lu JR: Thermophilic fermentation of acetoin and 2,3-butanediol by a novel ... Ui S, Okajima Y, Mimura A, Kanai H, Kobayashi T, Kudo T: Sequence analysis of the gene for and characterization of d-acetoin ...
Flavoring chemicals in e-cigarettes: diacetyl, 2,3-pentanedione, and acetoin in a sample of 51 products, including fruit-, ... Flavoring chemicals in e-cigarettes: diacetyl, 2,3-pentanedione, and acetoin in a sample of 51 products, including fruit-, ...
... and acetoin. The presence of esters in C wines suggest fruity and floral notes in these wines. Similarly, C wines had the ...
... acetoin, glucuronic acid, carnitine, myoinositol, sulfates, phosphates, and middle molecules. Levels of some of the guanidine ...
In addition to information on diacetyl, OSHA seeks information on acetoin, acetaldehyde, acetic acid, furfural, and other ...
Acetoin. Acetophenone. 2 Acetyl Pyridine. 2 Acetyl Pyrazine. Agrumen Aldehyde. Alcohol C-10. Alcohol C-12. Alcohol C-6. Alcohol ...
The absolute perfect system for storing and or steeping your juice! This set comes with the rack, and 50 Vials (with caps). This is the full set!. Great Little Test Tube (for use in the rack or set). The last number that is written with ink is 13ml. After that there is another line (14ml) and finally a top line that is molded into the test tube with "15ml" written upside down ...
MEDIDAS DISPONÍVEIS: 10ML / 30ML / 60ML / 100MLEssência Alimentícia Concentrada de Leite (TPA).ESTA ESSÊNCIA CONCENTRADA É APROVADA PELA FDA PARA USO EM ALIMENTOS, BEBIDAS E PRODUTOS PARA CONSUMO HUMANO.Informações adicionais: Essências Conce...
acetylmethylcarbinol - acetoin. All 20-letter words containing a, b On this page, we collect all words with A, B. To make ...
acetoin degradation. 66.67. 2 of 3. [Ref.: #66794]. d-xylose degradation. 63.64. ...
Product Characteristics: Water Soluble PG Based Acetoin Free Ingredients: Propylene Glycol, Natural & Artificial Flav ... This is the acetoin-free version of TFA Hazelnut. Flavour Uses: Candy Making, Ice Cream, Desserts, Whipped Cream, Coffee, Tea, ...
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Acetoin: Not Determined. *Acetyl Propionyl: Not Determined. *Suggested Starting Use: 2%-3% ...
acetoin biosynthetic process. 1.82% (1/55). 7.37. 0.006034. 0.030924. GO:0045149. acetoin metabolic process. 1.82% (1/55). 7.37 ...
Acetoin: 0 PPM. Acetyl Propionyl: 0 PPM. Suggested Starting Use: 2% - 3%. Storage: No heat or light. Ingredients: Propylene ...
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E-liquidy neobsahují diacetyl ani acetoin.. Buďte první, kdo napíše příspěvek k této položce. ...
  • Acetoin, along with diacetyl, is one of the compounds that gives butter its characteristic flavor. (wikipedia.org)
  • Because of this, manufacturers of partially hydrogenated oils typically add artificial butter flavor - acetoin and diacetyl - (along with beta carotene for the yellow color) to the final product. (wikipedia.org)
  • 2016 . Flavoring chemicals in e-cigarettes: diacetyl, 2,3-pentanedione, and acetoin in a sample of 51 products, including fruit-, candy-, and cocktail-flavored e-cigarettes. (annualreviews.org)
  • I think what you'll find is that flavorings we use can contain acetoin, a precursor to diacetyl, and acetyl propionyl, a diketone or the same type of molecule as diacetyl. (e-liquid-recipes.com)
  • Diacetyl, Acetoin and Acetyl Propionyl free. (vapelittle.com)
  • BFV are a complex mixture of volatile agents containing of diacetyl and butyric acid, two components of BFV, and to develop a hybrid computational fluid dynamic-physiologically diacetyl (2,3-butanedione), acetoin, 2-nonanone, acetic acid, based pharmacokinetic model (CFD-PBPK) to describe these and butyric acid, among other vapors (Boylstein et al. (cdc.gov)
  • TPA is very open about which of their flavors contain acetoin and acetyl propionyl. (e-liquid-recipes.com)
  • Contains Acetoin and Acetylpropionyl. (fsecig.com)
  • We used three constitutive and two inducible promoters to drive the expression of two fluorescent reporter proteins and a short acetoin biosynthesis pathway. (frontiersin.org)
  • Owing to its neutral nature, production and excretion of acetoin during exponential growth prevents over-acidification of the cytoplasm and the surrounding medium that would result from accumulation of acidic metabolic products, such as acetic acid and citric acid. (wikipedia.org)
  • The Voges-Proskauer test is a commonly used microbiological test for acetoin production. (wikipedia.org)
  • Acetoin is used as a food flavoring (in baked goods) and as a fragrance. (wikipedia.org)
  • Toxicity studies of acetoin and 2,3-pentanedione administered by inhalation to Wistar Han [Crl:WI(Han)] rats and B6C3F1/N mice. (nih.gov)
  • An overview of Genetic Toxicology Micronucleus Rats study conclusions related to Acetoin (513-86-0). (nih.gov)
  • Figures 4 and 5), the finalenzyme in the acetoin biosynthesis pathway and a metabolic indicator of anaerobic growth in L. monocytogenes [31]. (emlinhibitor.com)
  • 19. A potential flavor culture: Lactobacillus harbinensis M1 improves the organoleptic quality of fermented soymilk by high production of 2,3-butanedione and acetoin. (nih.gov)
  • Note: This flavor contains 'custard' ingredients: Acetoin. (perfumersapprentice.com)
  • Furthermore, acetoin was not detected in culture fluids of alkaline adapted L. monocytogenes EGD-e cells using a Voges-Proskauer method [32] but was at pH 7.3 (data not shown). (emlinhibitor.com)