How Many Atps Can Be Generated From Pelargonic Acid

Induced resistance to biotic stress in plants by natural compounds: Possible mechanisms

Hatem Boubakri , in Priming-Mediated Stress and Cross-Stress Tolerance in Ingather Plants, 2020

v.iv.three Hexanoic acrid

Hexanoic acid (HA) is a brusk-concatenation monocarboxylic acid present in strawberry ( Fragaria vesca L.) and arbutus (Arbutus unedo L.), which has been described to induce establish affliction resistance mainly through priming of host-defense force responses. ^{88, 89} After being used equally a soil drench, HA is absorbed and accumulated in the roots, and not translocated to other parts of the plants. ^ninety Recent studies showed that the application of HA in love apple (Solanum lycopersiccum Fifty.) plants induced specific changes that were able to affect the expression of Pseudomonas syringae virulence genes, highlighting for the first time that the awarding of elicitors not just activated host-defense reactions but as well might change the pathogen virulence. ⁹¹ HA has been also reported to provide important resistance levels in citrus to Alternaria alternata when applied as a soil drench. ⁹² This offered resistance past HA was accompanied by some molecular and cellular changes including increased levels of callose degradation, the expression of PGIP genes, and an aggregating of JA. ⁹² In long lasting assays, HA-treated plants showed enhanced levels of phenolic compounds, such as caffeic and chlorogenic acids. ⁹² In addition, HA treatment reduced the incidence of Xanthomonas citri subsp. citri by 50% in sweet orange plants (Citrus sinensis) and activated the expression of the PR-2 cistron. ⁹³

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Ghrelin

Yoshihiro Nishi , ... Masayasu Kojima , in Methods in Enzymology, 2012

2 Preparing Food and H2o Containing MCFAs or MCTs

ii.1 Preparation of drinking h2o with MCFAs

MCFAs (n -hexanoic acrid, n-octanoic acid, or n-decanoic acid (Sigma-Aldrich, Japan)) were dissolved in distilled h2o at a concentration of 5   mg/ml (Nishi et al., 2005a). At this concentration, no precipitates were formed at room temperature (25   °C).

2.2 Preparation of grub with MCTs

Standard laboratory chow (CLEA Rodent Nutrition: CE-2, CLEA Nippon Inc., Osaka, Japan) was used. The CE-2 chow contained 50.3% carbohydrate, 25.4% protein, and 4.four% fat. MCTs consisting of glyceryl trihexanoate (C6-MCT) (Tokyo-Kasei, Tokyo, Nippon), glyceryl trioctanoate (C8-MCT) (Wako Pure Chemical, Osaka, Nihon), glyceryl tridecanoate (C10-MCT) (Wako Pure Chemical), or glyceryl triheptanoate (Fluka Chemie, Switzerland) were mixed into the CE-2 grub at a concentration of 5% (w/w) as described beneath (Nishi et al., 2005a).

1.

Weigh out a portion of the CE-2 chow and sprinkle an advisable amount of the liquid MCT (v% due west/w of the CE-2) onto information technology (e.g., v.0   m of liquid MCT onto 95   g of CE-ii grub).

2.

Permit the MCT to soak into the CE-2 for at least 2   h at room temperature.

iii.

In the case of C10-MCT, which is a solid at room temperature, deliquesce the C10-MCT by heating in a thermostat chamber at 60 ^oC.

four.

Sprinkle the appropriate amount of liquid C10-MCT (5% west/west to CE-ii) onto the CE-2, which is prewarmed to 60 ^oC.

5.

Rut the C10-MCT-sprinkled CE-2 in a thermostat chamber at 60   °C for at to the lowest degree two   h to allow the C10-MCT to soak into the CE-2.

6.

Shop the C6-, C8-, or C10-MCT-soaked CE-2 at 4   °C until use.

2.3 Feeding weather

Male C57BL/6JJcl mice (CLEA Japan, Inc., Osaka, Japan) weighing 20–25   g were used. Mice were given ad libitum access to either the MCT-mixed chow (v% westward/w) or the MCFA-mixed water (five   mg/ml) for 0–14 days (Nishi et al., 2005a). To minimize the denaturing of MCFAs or MCTs, drinking water and grub were inverse twice a calendar week.

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Mitochondria, tertiary Edition

Chantal Priesnitz , ... Thomas Becker , in Methods in Prison cell Biological science, 2020

6.one.1 Material

3x Gel Buffer: 200   mM ɛ-amino-n-caproic acrid, 150   mM Bis-Tris/HCl pH 7.0

10x Anode Buffer: 500   mM Bis-Tris/HCl pH 7.0

10x Cathode Buffer: 500   mM Tricine, 150   mM Bis-Tris pH 7.0, 0.2% (w/five) Coomassie One thousand

Acrylamide: 49.v% (w/v) acrylamide, 3% (w/v) Bis-acrylamide

CAUTION: Acrylamide is toxic and irritant. Gloves should be worn when preparing and working with acrylamide. The utilise of a hood is recommended.

10x BN-Loading dye: v% (w/v) Coomassie bluish G, 500   mM ɛ-amino-n-caproic acid, 100   mM Bis-Tris pH 7.0

Solubilization buffer: 0.5–ane.5% (w/v) digitonin (other detergents [due east.g. Triton X-100, dodecylmaltoside] may also be suitable), 20   mM Tris/HCl pH 7.4, 0.i   mM EDTA, 50   mM NaCl, ten% (v/v) glycerol, 1   mM PMSF

SEM buffer: 250   mM sucrose, 1   mM ETDA, 10   mM MOPS/KOH pH 7.ii

Note: Since protein complexes can be temperature labile, absurd every solution prior to electrophoresis.

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Date Fruits

Issoufou Amadou , in Nutritional Composition of Fruit Cultivars, 2016

Desert Date

Desert date pulp extract is comprised of diverse flavour volatile compounds predominant with hexanoic acid and ethyl ester ( Tabular array 6). The overall amount of esters in wild desert date fruit pulp extract is the compounds that mainly responsible for fruity scent (El Arem et al., 2011; Paravisini et al., 2014). On the other hand, a low aldehyde content was observed (Table 6) in desert dates. This shows that desert dates have been used and accepted in the mixture of folk medicines (Kamel, 1998; Kamel and Koskinen, 1995; Koko et al., 2005). Ideally aldehydes are compounds responsible for the odor quality of the fruit, and their concentrations vary with the nature of the fruit. The likely flavor volatile compounds common in desert date and appointment palm fruits are hexanal, nonanal, ethyl acetate, one-pentanol, and ane-hexanol. In add-on, compounds such every bit cyclotetrasiloxane, octamethyl-, and 2,3-pentanedione are also among the most predominant found in the desert date. Alcohols are known to influence in the juice flavor; over 10 alcoholic compounds have been identified in the desert date, although fewer are present in date palm fruit (Table 6). Alcohol was identified in previous studies as an active aroma compound in unpasteurized fruit juice and heated juice by headspace–solid phase microextraction-Osme (El Arem et al., 2011; Sagna et al., 2014; Sarker et al., 2000; Wen et al., 2014). 1-Octen-iii-ol was the most abundant alcohol found in the desert date (Table six).

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Volume 3

M.-North. Leclercq-Perlat , in Encyclopedia of Dairy Sciences (Third Edition), 2022

Lipolysis and Free Fatty Acids: Important Aroma Precursors

Phenomena that generate FFAs are meaning in ripening. Concentrations of butanoic, caproic, and capric acids are higher than the olfactive threshold in fat, and thus probably directly contribute to the overall flavor intensity. Nevertheless, the products of catabolism generated by microorganisms are more important for flavor than the FFAs that accumulate. In the rind, and later on twenty-four hour period 6, the curt and medium-concatenation FFAs are in the dissociated form, that is to say, they are much less volatile than when in molecular course due to a rind pH college than the pK (close to 5.0). The dissociated course of FFAs are easily diffused. These may significantly alter the aroma impact of short chain fat acids (Table iv, Leclercq-Perlat et al., 2007).

Table 4. Correlations established between viable cell counts (log_x  cfu/g dry out thing) of One thousand. marxianus, G. candidum, and P. camemberti to make up one's mind microorganisms that could be involved in the formation of FFAs under investigation, classified by the number of carbon atoms (brusk-, medium-, or long-concatenation FFA), and these phenomena reported by Leclercq-Perlat et al. (2007) [ ] microorganism appears to have a small event. B. aurantiacum ATCC9175 was non demonstrated to exist lipolytic

FFA	FFA classes	Microorganisms related to FFA formation	Highlighted phenomena
Butanoic acrid (C4)	Curt-concatenation	Chiliad. marxianus; G. candidum	Lipolysis did not explain this production
Caproic acid (C6)	Short-chain	[K. marxianus], G. candidum	Diffusion from the rind to the core
Caprylic acrid (C8)	Medium-chain	[K. marxianus], G. candidum
Pelargonic acid (C9)	Medium-concatenation	Grand. candidum	Diffusion from the rind to the core
Capric acid (C10)	Medium-chain	K. marxianus, G. candidum
Lauric acid (C12)	Medium-chain	K. marxianus, G. candidum	Diffusion from the rind to the core β-Oxidation in the rind
Tridecanoic acid (Cthirteen)	Long-chain	Yard. candidum, P. camemberti	Chemical machine oxidation
Myristic acid (C14)	Long-concatenation	Thou. candidum, P. camemberti
Palmitic acid (Cxvi)	Long-chain	G. candidum, P. camemberti
Stearic acrid (Ceighteen)	Long-concatenation	G. candidum, P. camemberti	Improvidence from rind to cadre

M. candidum and P. camemberti spores tend to produce long-chain FFAs of pocket-sized olfactive importance (Leclercq-Perlat et al., 2007). Chiliad. candidum plays a pregnant office in Camembert season. The lipolytic enzymes of P. camemberti are mainly produced past the mycelium and do not lengthened to the cadre whereas Penicillium swelling spores are efficient in the conversion of FFAs into methyl ketones or octen-i-ol-three.

The differences in some medium-concatenation and stearic acid concentrations betwixt the rind and the cadre reveal diffusion from the rind, where these acids are produced, to the core. β-Oxidation of the FFAs on the surface takes place rapidly in the presence of oxygen, bringing well-nigh the breakdown of the residual FFAs in the rind.

Pelargonic and tridecanoic acids are rarely found and are mainly produced during M. candidum and P. camemberti mycelium growth (day seven–day fourteen) provided past unsaturated FFAs disrupted by lipoxygenase and hydroxide lyases. C9:0 is produced in the rind and migrates within the cheese, whereas C13:0 is produced at the same rates in these two cheese sections. A function of tridecanoic acid concentrations can be due to chemical automobile oxidation in the presence of peroxides of biological origin and non only due to P. camemberti enzymatic activity. Many significant correlations between FFA concentrations, nitrogen fractions, and volatile chemical compound concentrations resulting from proteolysis are establish.

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Organic and Fat Acid Production, Microbial

I. Goldberg , J.Southward. Rokem , in Encyclopedia of Microbiology (Third Edition), 2009

Gluconic acid

Gluconic acrid (two,iii,4,5,6-pentahydroxy caproic acrid, C₆H₁₂O₇) ( Figure 6 ) is a noncorrosive, nontoxic, balmy organic acrid with a brown clear advent. It is very soluble in water and has a mild and refreshing gustation. It is a skilful chelator at high pH, with better activity than commonly used chelators.

Figure six. Gluconic acid.

Gluconic acid was discovered in 1870 past Hlasiwetz and Habermann, when glucose was oxidized with chlorine. In 1922 it was isolated from a strain of A. niger. Afterward, other filamentous fungi, such as Penicillium, Scopulariopsis, Gonatobotrys, and Gliocladium, and too oxidative leaner, such as strains of Pseudomonas, Gluconobacter (Acetobacter), Moraxella, Micrococcus, Enterobacter, and Zymomonas were found to produce gluconic acid. Already in the 1940s it was possible to obtain expert yields of gluconic acrid using A. niger past fermentation, neutralizing the accumulating acid with calcium carbonate.

The physiological functions of gluconic acid aggregating for these organisms are not clear; one possibility is its contribution to the competitiveness of the organism, removing glucose from the shut environment. In the example of P. expansum (a phytopathogenic fungus), it was demonstrated that secreted gluconic acid contributed to the colonization and disease evolution of apple tissues by this mucus.

Gluconic acid is used in the manufacture of metal, leather, and food. Information technology has been accredited with the capability of inhibiting bitterness in foods. Sodium gluconate is permitted in food and information technology has GRAS (generally recognized as rubber) condition. This table salt is also utilized as a sequestering agent in many detergents, and added to cement to improve the hardening process.

The formation of gluconic acid is different from most other organic acids, since information technology is formed outside the cytoplasmic membrane, by the enzyme glucose oxidase. This enzyme has been shown to be localized in the cell wall, at least for fungi known to accumulate gluconic acid. Glucose in the medium is oxidized in a 2-pace reaction to gluconic acid; showtime glucose oxidase oxidizes β-d-glucopyranose to d-glucono-1,v lactone with the formation of hydrogen peroxide, acted upon by catalase to class h2o and oxygen ( Figure seven ). The hydrolysis of the lactone is spontaneous in aqueous solutions, only occurs six times faster with the enzyme gluconolactonase, resulting in gluconic acrid ( Effigy seven ).

Effigy vii. Biosynthesis of gluconic acrid. Reproduced from Ramachandran S, Fontanille P, Pandey A, and Larroche C (2006) Gluconic acid: Properties, applications and microbial product. Food Technology and Biotechnology 44: 185–195.

The main route of gluconic acid production has been past fermentation, mainly using A. niger in submerged fermentations. The two most important parameters of the fermentation is a high concentration of dissolved oxygen, used straight in the biosynthesis, and keeping pH 4.v–6.5, traditionally achieved by addition of calcium carbonate as the neutralizing agent. All-time results are obtained with a high glucose concentration (110–250   m   l⁻¹), low concentrations of nitrogen and phosphorus (<xx   mmol   l⁻ⁱ), and low concentrations of metal ions. Fermentations with almost quantitative yield (>xc% on a molar ground) are completed in less than 24   h. The fact that the oxidation reactions occur outside of the cells allows for reuse of the mycelium up to xiv times. In the current industrial method, neutralization with NaOH allows for the use of higher initial carbohydrate concentrations (upward to 350   grand   l⁻¹) and the pH is then maintained close to 6.5. Recently, enzymatic processes have been introduced past conversion of glucose syrups with less formation of byproducts and resulting in fewer problems in the downstream process.

There are alternative ways of gluconic acid production by chemical, electrochemical, and bioelectrochemical routes, but with lower yields than the fermentation processes. Bacteria, mainly Gluconobacter oxydans, are reported to be used by industry. Recently, a process based on Acetobacter methanolicus was developed. The procedure utilizes methanol equally the carbon source for growth, with the addition of glucose for its conversion to gluconic acid.

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Cheese | Camembert, Brie, and Related Varieties

M.-Northward. Leclercq-Perlat , in Encyclopedia of Dairy Sciences (Second Edition), 2011

Lipolysis and Free Fatty Acids: Important Aroma Precursors

Biochemical pathways liberating FFAs are significant in the ripening of Camembert-type cheeses. Concentrations of butanoic, caproic, and capric acids are higher than their flavor threshold adamant in a fatty medium and thus probably contribute directly to its overall flavor intensity. However, the products of catabolism generated by microorganisms are more important for season than the FFAs produced. In the rind and later on day 6, short- and medium-chain FFAs are in their dissociated grade, that is, they are much less volatile than when in their nonionized form, due to the rind pH being college than their p1000 _a (close to 5.0). The FFAs in their dissociated form diffuse easily. This may significantly change the aroma impact of short-chain fatty acids ( Table 4 ).

Table 4. Correlations established between viable cell counts (log₁₀ cfu g^-1 dry matter) of K. marxianus, G. candidum, and P. camemberti to determine microorganisms that can be involved in the germination of FFAs under investigation, classified past their number of carbon atoms (brusque-, medium-, or long-chain FFA), and the phenomena highlighted by Leclercq-Perlat et al. (2007)

FFA	FFA classes	Microorganisms related to FFA germination	Highlighted phenomena
Butanoic acid (Cfour)	Short-chain	M. marxianus; One thousand. candidum	Lipolysis did not explain this production
Caproic acid (Chalf-dozen)	Brusk-concatenation	[K. marxianus]; Thousand. candidum	Diffusion from the rind to the core
Caprylic acid (Ceight)	Medium-chain	[Thou. marxianus]; G. candidum
Pelargonic acid (C9)	Medium-concatenation	1000. candidum	Diffusion from the rind to the core
Capric acid (C10)	Medium-concatenation	K. marxianus; Chiliad. candidum
Lauric acid (C12)	Medium-chain	One thousand. marxianus; K. candidum	Diffusion from the rind to the core β-Oxidation in the rind
Tridecanoic acrid (C13)	Long-chain	G. candidum; P. camemberti	Chemical motorcar-oxidation
Myristic acid (C14)	Long-chain	G. candidum; P. camemberti
Palmitic acrid (C16)	Long-chain	One thousand. candidum; P. camemberti
Stearic acid (C18)	Long-concatenation	Thou. candidum; P. camemberti	Diffusion from the rind to the cadre

[ ] a microorganism appears involved in a minor fashion. B. aurantiacum ATCC9175 was not demonstrated to exist lipolytic.

Geotrichum candidum and P. camemberti spores tend to produce long-chain FFAs of minor olfactive importance. Geotrichum candidum plays a significant role in Camembert flavor. The lipolytic enzymes of P. camemberti are mainly produced past the mycelium and do not lengthened to the cadre, whereas the spores of Penicillium are efficient in converting FFAs into methyl ketones or octen-ane-ol-iii.

In the experiment under give-and-take, the differences in the concentrations of some medium-concatenation FFAs and stearic acid between the rind and the core revealed diffusion from the rind where these acids are produced to the core. β-Oxidation of FFAs on the surface takes place rapidly in the presence of oxygen, breaking down residual FFAs in the rind.

Pelargonic (C9:0) and tridecanoic (C13:0) acids, which are rarely found, were produced mainly during the growth of Thousand. candidum and P. camemberti mycelium (days 7–14) from unsaturated FFAs disrupted by lipoxygenase and hydroxide lyases. C9:0 was produced in the rind and migrated to inside of the cheese, whereas C13:0 was produced at the same rate in the rind and the cadre. Some tridecanoic acid could take been due to a chemical auto-oxidation in the presence of peroxides of biological origin and not due to the enzymatic activities of P. camemberti lone.

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Kinetic Characteristics of Booze Fermentation in Brewing: State of Fine art and Control of the Fermentation Procedure

Vesela Shopska , ... Georgi Kostov , in Fermented Beverages, 2019

13.iv.ii Modeling of the Secondary Metabolism of the Yeast Population

In contrast to main metabolism, where unlike variations in the models that describe information technology are possible, in secondary metabolism, cell-associated relationships are used. Only in case of VDK some differences can be observed, mainly due to the presence of a chemic phase in their reduction. The basis of the secondary metabolism models is the biochemistry of the procedure, and their grade is presented in Table 13.5.

Table thirteen.5. Mathematical Model for the Clarification of Secondary Metabolites, According to Ramirez and Maciejowski (2007)

College booze synthesis (FA) $\frac{dFA}{dt}=Y_{FA}\times \mu \times X\left(t\right)$

Ester synthesis (East) $\frac{dE}{dt}=Y_{\mathrm{East}}\times \mu \times \mathrm{Ten}\left(t\right)$

Aldehyde synthesis and reduction (A) $\frac{dA}{dt}=Y_A\times \mu \times X\left(t\right)-k_A\times A\times \mathrm{10}$

Vicinal diketones (VDK) $\frac{dVD\mathrm{Thou}}{dt}=Y_{5D\mathrm{Thou}}\times \mu \left(t\mathrm{,}T\right)\times X\left(t\mathrm{,}T\right)-{\mathrm{thousand}}_{X,VDK}\times \mathrm{Five}DK\left(t\mathrm{,}T\right)\times X\left(t\mathrm{,}T\right)$

In some cases, models for specific representatives of a given group of metabolites (ethyl acetate, ethyl caproate, etc.) tin be found in the literature, but the trend for their accumulation to be associated with biomass growth remains. The accurateness of the secondary metabolite models depends largely on the accuracy of the chosen model for describing the growth charge per unit of the yeast cells, only there are besides some features related to the biochemistry of the process. These peculiarities tin can exist summarized as follows:

•

Higher alcohol synthesis: higher alcohols are mainly synthesized (over 90%) during the chief fermentation, therefore the biomass growth charge per unit in this period is essential. The fermentation temperature is the main gene influencing the yield coefficient Y _FA ;

•

Ester synthesis: 60% of the esters are synthesized during the exponential phase and the remaining twoscore% during the stationary phase of biomass growth. Their synthesis is delayed compared to that of higher alcohols, since the latter are precursors to ester synthesis. This delay, still, is not commented past the model; the model is associated with biomass growth and its accuracy depends on the accuracy of the cell growth description;

•

Aldehyde synthesis and reduction: the germination of aldehydes during fermentation is associated with cell growth and the biosynthesis of higher alcohols from yeast oxo acids. They increase during the main fermentation and decrease during maturation. Their reduction is entirely related to the already formed biomass, so there is besides a second member in the equation, which is a part of the already synthesized biomass.

•

Vicinal diketones: diacetyl and 2,iii-pentanedione are synthesized during cell growth, so their increase is proportional to cell growth. In contrast to aldehydes, chemical reduction is possible in VDK, the rate of which depends on the fermentation temperature. At low fermentation temperatures, this process is very ho-hum and may not be taken into business relationship in the model for these metabolites. Reduction of diacetyl and 2,three-pentanedione is due to their consumption by yeasts and their transformation to the corresponding alcohol: 2,iii-butanediol and 2,3-pentanediol. The reduction rate is proportional to the concentration of biomass already accumulated and the electric current concentration of VDK.

Details of the parameters identified for these models are presented in Tabular array 13.1. The data brand it possible to compare different fermentation regimes with respect to the yields of the relevant metabolites. The accuracy of these models is entirely dependent on the chosen model for describing the primary metabolism. Furthermore, the accurateness of the secondary metabolism models depends on the fermentation temperature. Nosotros tin can summarize that yield coefficients can also be regarded as charge per unit constants every bit they depend on the temperature.

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A New Approach to Multi-Site and Multi-Scale Rehabilitation by Phytoextraction

Claude Grison , ... Jacques Biton , in Ecocatalysis, 2015

1.1.10.two Determination

An original and enantiomerically pure synthesis of the isopropyl ester 2-keto-3-deoxy-D-erythro -hexanoic acid was obtained with the best yield. The chirality of the final production was controlled during Swern oxidation phase followed by Darzens diastereoselective condensation resulting in the epimerization of the position of β in KDG. The results reveal the all-time synthesis of partially or completely protected KDG. The assimilation of partially protected KDG was tested on the microbial diversity of the soil of Saint-Laurent-Le-Minier by means of growth assays. The growth of 25% of the total microbial population was favored by the isopropyl ester of 2-keto-3-deoxy-D- erythro-hexanoic acid. These bacterial strains, which are capable of producing ammonium, tin can provide significant benefits to agriculture, particularly to food-poor soil. This microbial biotechnology favored by the uptake of the isopropyl ester of KDG is a promising green process to restore polluted soils, stimulating a revegetation project.

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Amino acid metabolism in relationship to cheese flavor development

B. Ganesan , B.C. Weimer , in Improving the Flavour of Cheese, 2007

Catabolism of branched chain amino acids

Multiple genera produce fatty acids in cheese environmental conditions. Acetic, propionic, isobutyric, n-butyric, isovaleric and northward-caproic acids are produced past lactococci and lactobacilli, the production depending on the strain (Nakae and Elliott, 1965b). The pH optima for fat acrid production vary for each organism. Lactobacilli produce valeric acid and its isomers from leucine and isoleucine at a lower pH (Nakae and Elliott, 1965a). Lactobacillus delbrueckii ssp. bulgaricus produces propionic and northward-butyric acids, while L. casei ssp. casei, L. delbrueckii ssp. lactis and Streptococcus salivarius ssp. thermophilus produce acetic acid (Thornhill and Cogan, 1984). In like experimental conditions, Fifty. lactis ssp. cremoris produces more BCFAs than Fifty. lactis ssp. lactis (Crow et al., 1993). Brevibacterium linens produces acerb acid from glycine, alanine and leucine, isovaleric acid from leucine, and caproic acid from cystine, alanine and serine (Hosono, 1968a, b). Propionibacterium freudenreichii produces isovaleric acrid from leucine (Thierry et al., 2002). Isovaleric and 3-methyl butyric acids found in Livarot and Pont l'Evêque cheeses are produced from leucine and isoleucine, respectively (Stark and Adda, 1971). Transamination and Strecker degradation yield branched chain aldehydes (Flim-flam and Wallace, 1997).

Xi genomes of LAB and related bacteria were recently sequenced past the LABGC and JGI (Walnut Creek, CA). Comparative metabolic analysis of the draft sequenced genomes (http://www.jgi.doe.gov/JGI_microbial/html/index.html) and the publicly available Lactococcus lactis subsp. lactis IL1403 genome (Bolotin et al., 1999, 2001) revealed the presence of more than 100 genes that are either directly or indirectly involved in production of fatty acids or in production of substrates for catabolism to fatty acids via substrate-level phosphylation to produce ATP. The presence of these genes indicates the feasibility of BCAA catabolism to fat acids and survival during substrate exhaustion. Genomic data, along with metabolomics and bioinformatics, was recently used to narrate the catabolic pathways of BCAAs in lactococci (Ganesan et al., 2006).

Lactococci produce 2-methyl butyric, isobutyric and isovaleric acids via a 12-pace mechanism (Fig. four.8) (Ganesan et al., 2006). ATases are the enzymes involved in the kickoff stride of the conversion of amino acids to flavor compounds (Ganesan et al., 2004a, b; Ganesan and Weimer, 2004; Yvon et al., 1997). The pathway further uses general classes of enzymes such as dehydrogenases, acyl transferases, carboxylases, dehydratases, and acyl kinases to generate BCFAs from leucine, isoleucine and valine. Lactococci possess more ane branched chain ATase (BAT) or other ATases (Chambellon and Yvon, 2003) with overlapping substrate specificities. Mutants of BAT are capable of growth on α-ketoisocaproate (Atiles et al., 2000). BAT catabolizes the BCAAs leucine, isoleucine and valine to yield their corresponding α-keto acids (Yvon et al., 2000). Since the genes related to these pathways are present in LAB (Bolotin et al., 1999, 2001) (http://world wide web.jgi.doe.gov/JGI_microbial/html/index.html), they may be expressed during cheese ripening and allow cell survival. In cheese, BCAAs may be transported faster at a low pH of 5.2 than at pH seven.2 (Konings et al., 1989). BCAAs are then utilized by the cell to produce ATP for ATP-driven send systems. This is one of the roles of BCAA catabolism by the starter culture in cheese. Amino acrid catabolism to fat acids, peculiarly BCAA catabolism, provides free energy equally ATP and other molecules essential for cellular survival. Notably the BCAA catabolic pathway of lactococci shares motifs and purposes similar to glycolysis (Ganesan et al., 2006).

Fig. iv.8. Branched chain amino acrid catabolism pathways of Brevibacterium linens (producing branched chain fatty acid 1) and Lactococcus lactis (producing branched concatenation fatty acrid ii) Enzymes involved in the various steps are: (ane) amino transferase, (ii) dehydrogenase, (iii) acyl transferase, (four) carboxylase, (5) dehydratase, (six) 3-hydroxy-3-methylglutaryl-CoA synthase, (7) phosphotransacylase/phosphatase, and (eight) acyl kinase.

reproduced with modifications and combined from Ganesan et al. (2004a) and Ganesan et al. (2006), respectively.

Amino acid to fatty acid catabolic pathways are identified in both lactic and non-lactic genera (Bolotin et al., 1999, 2001; Fraley et al., 1998) (http://www.jgi.doe.gov/JGI_microbial/html/alphabetize.html), and are characterized in some genera both enzymatically and genetically. Though the purposes are different, the serial of reactions in both cases higher up are initiated by an ATase (Choi et al., 2000; Heath and Rock, 1996; Ward et al., 1999, 2000). A global transcriptional regulator, codY, senses intracellular levels of BCAAs and aids in catabolism of amino acids via AAT and BAT (Chambellon and Yvon, 2003; Guedon et al., 2001; Petranovic et al., 2004). The physiological rationale for BCAA catabolism to BCFAs seems to be carbohydrate starvation (Ganesan et al., 2004a, b, 2006).

Fatty acid product pathways are agile in weather condition coordinating to cheese ripening (Heath and Rock, 1996; Ward et al., 2000). LAB generate fat acids, whose purpose is nevertheless unknown, except for jail cell wall fatty acid biosynthesis, but a common theme in all known amino acrid to fatty acid pathways is coupling reactions with ATP generation by substrate level phosphorylation and/or regeneration of redox compounds, like NADH, nether anaerobic conditions. These pathways need to exist active in the absenteeism of fermentable carbohydrates for the bacteria to survive.

Tabular array 4.3 shows Gibbs free energy change values (ΔYard ⁰′) at pH 7 for the catabolism of amino acids to fatty acids. A negative ΔOne thousand ⁰′ value means that the pathway produces energy (i.e. it is exergonic) and is energetically favorable. From the values of ΔG ⁰′ in the table, the catabolic mechanisms of most amino acids to fatty acids, except threonine, are favorable. Especially, the catabolic mechanisms of BCAAs to BCFAs are favorable. The free energy needed to generate one ATP is ∼–30.5kJ/mol. Hence, from the ΔG ⁰′ values, we meet that multiple ATP molecules can be generated from these pathways. One such physiological condition in which these pathways will be relevant is the onset of carbohydrate exhaustion during cheese ripening and growth in culture, commonly referred as saccharide starvation.

Tabular array 4.three. Bioenergetics of amino acid catabolism to fatty acids

Amino acid	Pathway	Fatty acid production	ΔG 0′ (kJ/mol)
Glycine		Acerb acid	−98.60
Isoleucine		Isovaleric acid	−56.29
Leucine		2-Methyl-valeric acid	−46.38
Threonine		Propionic + formic acid	+53.69
Valine		Isobutyric acid	−52.74
Glutamic acid	Hydroxypropionate	Butyric + acerb acid	−376.threescore
Glutamic acid	Methylaspartate	Butyric + acetic acrid	−234.63

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