THE ANAEROBIC DISSIMILATION OF D-XYLOSE-1-C14, D-XYLOSE-2-C14, AND D-XYLOSE-5-C14 BY LEUCONOSTOC MESENTEROIDES

1955 ◽  
Vol 33 (1) ◽  
pp. 622-626 ◽  
Author(s):  
H. A. Altermatt ◽  
A. C. Blackwood ◽  
A. C. Neish

D-Xylose was dissimilated anaerobically by Leuconostoc mesenteroides to an equimolecular mixture of acetic and lactic acids. Xylose-1-C14 gave methyl-labelled acetic acid, xylose-2-C14 gave carboxyl-labelled acetic acid, and xylose-5-C14 gave methyl-labelled lactic acid. The amount of C14 found in any other position was less than one per cent of the total.

1955 ◽  
Vol 33 (4) ◽  
pp. 622-626 ◽  
Author(s):  
H. A. Altermatt ◽  
A. C. Blackwood ◽  
A. C. Neish

D-Xylose was dissimilated anaerobically by Leuconostoc mesenteroides to an equimolecular mixture of acetic and lactic acids. Xylose-1-C14 gave methyl-labelled acetic acid, xylose-2-C14 gave carboxyl-labelled acetic acid, and xylose-5-C14 gave methyl-labelled lactic acid. The amount of C14 found in any other position was less than one per cent of the total.


2011 ◽  
Vol 74 (5) ◽  
pp. 820-825 ◽  
Author(s):  
YOEN JU PARK ◽  
JINRU CHEN

This study was conducted to evaluate the abilities of five neutralizing agents, Dey-Engley (DE) neutralizing broth (single or double strength), morpholinepropanesulfonic acid (MOPS) buffer, phosphate-buffered saline (PBS), and sodium thiosulfate buffer, in mitigating the activities of acetic or lactic acid (2%) and an alkaline or acidic sanitizer (a manufacturer-recommended concentration) againt the cells of Shiga toxin–producing Escherichia coli (STEC; n = 9). To evaluate the possible toxicity of the neutralizing agents to the STEC cells, each STEC strain was exposed to each of the neutralizing agents at room temperature for 10 min. Neutralizing efficacy was evaluated by placing each STEC strain in a mixture of sanitizer and neutralizer under the same conditions. The neutralizing agents had no detectable toxic effect on the STEC strains. PBS was least effective for neutralizing the activity of selected organic acids and sanitizers. Single-strength DE and sodium thiosulfate neutralized the activity of both acetic and lactic acids. MOPS buffer neutralized the activity of acetic acid and lactic acid against six and five STEC strains, respectively. All neutralizing agents, except double-strength DE broth, had a limited neutralizing effect on the activity of the commercial sanitizers used in the study. The double-strength DE broth effectively neutralized the activity of the two commercial sanitizers with no detectable toxic effects on STEC cells.


1989 ◽  
Vol 52 (10) ◽  
pp. 688-695 ◽  
Author(s):  
NORMAH AHAMAD ◽  
ELMER H. MARTH

Inhibition of Listeria monocytogenes CA and V7 by of acetic, citric, and lactic acids at 7, 13, 21, and 35°C was investigated. Statistical analysis showed interactive effects between temperature, types, and concentration of acids and strains of the pathogen. Presence of up to 0.1% of acetic, citric and lactic acids in the medium (tryptose broth) inhibited growth; the degree of inhibition increased as the temperature of incubation decreased (no growth occurred in the presence of 0.1% acetic acid at 7°C). L. monocytogenes was inactivated at all temperatures when acid concentrations in the medium were 0.3% or greater. Acetic acid was most detrimental to L. monocytogenes followed in order by lactic and citric acids. The antilisterial activity of these acids coincided with their degree of undissociation. Citric and lactic acids, with larger dissociation constants, were less detrimental to the pathogen than was acetic acid.


1959 ◽  
Vol 5 (5) ◽  
pp. 547-560 ◽  
Author(s):  
O. Ciferri ◽  
E. R. Blakley

The degradation of 2-keto-D-gluconate by Leuconostoc mesenteroides is shown to proceed according to the following pathway: 2-keto-D-gluconate → 2-keto-6-phospho-D-gluconate → 6-phospho-D-gluconate → D-ribulose-5-phosphate + CO2 → D-xylulose-5-phosphate → acetyl-phosphate + D-glyceraldehyde-3-phosphate.Cells grown on 2-keto-D-gluconate were shown previously to possess an adaptive and specific 2-ketogluconokinase. These cells also contained a reductase that reduced 2-keto-6-phospho-D-gluconate to 6-phospho-D-gluconate in the presence of DPNH or TPNH, 6-phospho-D-gluconate-dehydrogenase, phosphoketolase, D-ribulose-5-phosphate-3-epimerase, and acetokinase. The 2-keto-6-phospho-D-gluconate-reductase which was also present in cells grown on D-gluconate shows optimal activity between pH 4.5 and 6.5 and is rapidly inactivated by heat. The 6-phospho-D-gluconate-dehydrogenase specific for DPN has an optimum pH between 7.2 and 7.7 and is stable when heated to 50 °C for 5 minutes.The production of carbon dioxide or pentulose-phosphate with extracts from cells grown on 2-keto-D-gluconate proceeded more rapidly with 2-keto-6-phospho-D-gluconate as the substrate than with 6-phospho-D-gluconate. This difference in rates was eliminated if a system to recycle hydrogen such as alcohol dehydrogenase and acetaldehyde or pyruvate to couple with lactic acid dehydrogenase was provided. Thus the existence of an alternate pathway for the catabolism of 2-keto-6-phospho-D-gluconate to carbon dioxide, acetic acid, and lactic acid does not appear to exist.


1960 ◽  
Vol 6 (1) ◽  
pp. 107-114
Author(s):  
E. R. Blakley ◽  
A. C. Blackwood

The rate of utilization of 2-keto-D-gluconate and the accumulation of pentulose by resting cells of Leuconostoc mesenteroides is affected markedly by pH, Below pH 5, 2-keto-D-gluconate is utilized slowly and pentulose accumulates in the fermentation medium. The pentulose was separated by column chromatography and identified as D-xylulose and D-ribulose. The products of the fermentation of 2-keto-D-gluconate by resting cells, in addition to pentulose, are carbon dioxide, acetic acid, and lactic acid, as expected from the studies with growing cultures. The results obtained are unexpected when considered with what is known about the metabolism of 2-keto-D-gluconate by this organism.


1940 ◽  
Vol 11 (3) ◽  
pp. 243-265 ◽  
Author(s):  
A. Cunningham ◽  
A. M. Smith

1. The microflora of A.I.V. silage consists mainly of lactic acid bacteria—lactobacilli, streptococci, micrococci and sarcinae. Some samples also contain yeasts and yeast-like organisms.2. Among the lactobacilli, both homo- and heterofermentative types are represented. The former include strains ofLactobacillus plantarum(Orla- Jensen) Bergey et. al.; in the heterofermentative groupL. brevis(Orla-Jensen) Bergey et al. has been found.3. Cultures of a motile homofermentative lactobacillus were isolated; this appears to be a new type. Among the unidentified heterofermentative lactobacilli, forms which may prove to be similar to the inactive group of Pederson were encountered.4. The homofermentative streptococci were found to belong to the Streptococcus lactis group; the heterofermentative forms were identified withLeuconostoc mesenteroides(Cienkowski) van Tieghem.5. Strains of unidentified homofermentative micrococci and sarcinae were isolated and shown to possess characteristics not usually associated with organisms of these types.6. Streptococci, micrococci and motile lactobacilli were found mainly in fodder recently ensiled; the majority of the lactobacilli and sarcinae were associated with the older samples.7. The characteristics which proved to be most valuable for the differentiations of the organisms were ability to produce carbon dioxide, percentage of lactic acid formed and lactic-acetic acid ratio.


2002 ◽  
Vol 68 (4) ◽  
pp. 1616-1623 ◽  
Author(s):  
K. C. Thomas ◽  
S. H. Hynes ◽  
W. M. Ingledew

ABSTRACT Acetic acid (167 mM) and lactic acid (548 mM) completely inhibited growth of Saccharomyces cerevisiae both in minimal medium and in media which contained supplements, such as yeast extract, corn steep powder, or a mixture of amino acids. However, the yeast grew when the pH of the medium containing acetic acid or lactic acid was adjusted to 4.5, even though the medium still contained the undissociated form of either acid at a concentration of 102 mM. The results indicated that the buffer pair formed when the pH was adjusted to 4.5 stabilized the pH of the medium by sequestering protons and by lessening the negative impact of the pH drop on yeast growth, and it also decreased the difference between the extracellular and intracellular pH values (ΔpH), the driving force for the intracellular accumulation of acid. Increasing the undissociated acetic acid concentration at pH 4.5 to 163 mM by raising the concentration of the total acid to 267 mM did not increase inhibition. It is suggested that this may be the direct result of decreased acidification of the cytosol because of the intracellular buffering by the buffer pair formed from the acid already accumulated. At a concentration of 102 mM undissociated acetic acid, the yeast grew to higher cell density at pH 3.0 than at pH 4.5, suggesting that it is the total concentration of acetic acid (104 mM at pH 3.0 and 167 mM at pH 4.5) that determines the extent of growth inhibition, not the concentration of undissociated acid alone.


Fermentation ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 59
Author(s):  
Timothy J. Tse ◽  
Daniel J. Wiens ◽  
Jianheng Shen ◽  
Aaron D. Beattie ◽  
Martin J. T. Reaney

As barley and oat production have recently increased in Canada, it has become prudent to investigate these cereal crops as potential feedstocks for alcoholic fermentation. Ethanol and other coproduct yields can vary substantially among fermented feedstocks, which currently consist primarily of wheat and corn. In this study, the liquified mash of milled grains from 28 barley (hulled and hull-less) and 12 oat cultivars were fermented with Saccharomyces cerevisiae to determine concentrations of fermentation products (ethanol, isopropanol, acetic acid, lactic acid, succinic acid, α-glycerylphosphorylcholine (α-GPC), and glycerol). On average, the fermentation of barley produced significantly higher amounts of ethanol, isopropanol, acetic acid, succinic acid, α-GPC, and glycerol than that of oats. The best performing barley cultivars were able to produce up to 78.48 g/L (CDC Clear) ethanol and 1.81 g/L α-GPC (CDC Cowboy). Furthermore, the presence of milled hulls did not impact ethanol yield amongst barley cultivars. Due to its superior ethanol yield compared to oats, barley is a suitable feedstock for ethanol production. In addition, the accumulation of α-GPC could add considerable value to the fermentation of these cereal crops.


2021 ◽  
Vol 9 (5) ◽  
pp. 1044
Author(s):  
Jeong A Kim ◽  
Geun Su Kim ◽  
Se Mi Choi ◽  
Myeong Seon Kim ◽  
Do Young Kwon ◽  
...  

Hardening of cheese is one of major issues that degrade the quality of Home Meal Replacement (HMR) foods containing cheese such as Cheese-ddukbokki rice cake (CD, stir-fried rice cakes with shredded cheese). The quality of cheese, such as pH, proteolytic, and flavor properties, depends on various lactic acid bacteria (LAB) used in cheese fermentation. The hardening of cheese is also caused by LAB. In this study, various LAB strains were isolated from CD samples that showed rapid hardening. The correlation of LAB with the hardening of cheese was investigated. Seven of the CD samples with different manufacturing dates were collected and tested for hardening properties of cheese. Among them, strong-hardening of cheese was confirmed for two samples and weak-hardening was confirmed for one sample. All LAB in two strong-hardening samples and 40% of LAB in one weak-hardening sample were identified as Latilactobacillus curvatus. On the other hand, most LAB in normal cheese samples were identified as Leuconostoc mesenteroides and Lactobacillus casei. We prepared cheese samples in which L. curvatus (LC-CD) and L. mesenteroides (LM-CD) were most dominant, respectively. Each CD made of the prepared cheese was subjected to quality test for 50 days at 10 °C. Hardening of cheese with LC-CD dominant appeared at 30 days. However, hardening of cheese with LM-CD dominant did not appear until 50 days. The pH of the LC-CD was 5.18 ± 0.04 at 30 days, lower than that of LM-CD. The proteolytic activity of LC-CD sample was 2993.67 ± 246.17 units/g, higher than that of LM-CD sample (1421.67 ± 174.5 units/g). These results indicate that high acid production and high protease activity of L. curvatus might have caused hardening of cheese.


Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 894
Author(s):  
Johannes Pitsch ◽  
Georg Sandner ◽  
Jakob Huemer ◽  
Maximilian Huemer ◽  
Stefan Huemer ◽  
...  

Fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) are associated with digestive disorders and with diseases such as irritable bowel syndrome. In this study, we determined the FODMAP contents of bread, bakery products, and flour and assessed the effectiveness of sourdough fermentation for FODMAP reduction. The fermentation products were analyzed to determine the DP 2–7 and DP >7 fructooligosaccharide (FOS) content of rye and wheat sourdoughs. FOSs were reduced by Acetobacter cerevisiae, Acetobacter okinawensis, Fructilactobacillus sanfranciscensis, and Leuconostoc citreum to levels below those in rye (−81%; −97%) and wheat (−90%; −76%) flours. The fermentation temperature influenced the sourdough acetic acid to lactic acid ratios (4:1 at 4 °C; 1:1 at 10 °C). The rye sourdough contained high levels of beneficial arabinose (28.92 g/kg) and mannitol (20.82 g/kg). Our study contributes in-depth knowledge of low-temperature sourdough fermentation in terms of effective FODMAP reduction and concurrent production of desirable fermentation byproducts.


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