Molar growth yields and fermentation balances of Lactobacillus casei L3 in batch cultures and in continuous cultures.
TL;DR: Fermentation balances determined for different substrates in batch and continuous cultures of Lactobacillus casei revealed two pathways of pyruvate conversion by this organism, a reduction to lactate and the phosphoroclastic cleavage, and it was concluded that the intracellular level of fructose-1,6-diphosphate controlled the pathway of PyruVate conversion.
Abstract: SUMMARY: Fermentation balances determined for different substrates in batch and continuous cultures of Lactobacillus casei revealed two pathways of pyruvate conversion by this organism, a reduction to lactate and the phosphoroclastic cleavage. Pyruvate formed anaerobically from mannitol and citrate was split by the phosphoroclastic enzyme. Lactate was the main fermentation product formed during aerobic growth on mannitol and anaerobic and aerobic growth on glucose. In glucose-limited continuous cultures pyruvate conversion was dependent on the dilution rate. At low dilution rates glucose was fermented exclusively to acetate, ethanol and formate. At high rates only small amounts of acetate, ethanol and formate were formed and lactate production was maximal. Lactate dehydrogenase of L. casei had an absolute requirement for fructose-1,6-diphosphate and manganous ions. The specific activity of lactate dehydrogenase did not differ significantly at different dilution rates. It was concluded that the intracellular level of fructose-1,6-diphosphate controlled the pathway of pyruvate conversion. In batch cultures Y
ATP values were between 18.2 and 20.9. No evidence for oxidative phosphorylation was found. In continuous cultures YATP values varied from 18.7 at low dilution rates to 23.5 at high dilution rates. From the dependence of YATP on the dilution rate, a maintenance coefficient of 1.52 x 10-3 was calculated. The Y
ATP value corrected for energy of maintenance was 24.3. The possibility that the molar growth yields were erroneously high because of assimilation of growth substrate into intracellular polysaccharides, or because of energy yield from components of the medium other than the added energy source, was excluded.
Citations
More filters
TL;DR: This article corrects the article on p. 100 in vol.
Abstract: [This corrects the article on p. 100 in vol. 41.].
3,345 citations
01 Jan 1993
TL;DR: The present taxonomy relies partly on true phylogenetic relationships, largely based on morphology, mode of glucose fermentation, growth at different temperatures, configuration of the lactic acid produced, ability to grow at high salt concentrations, and acid or alkaline tolerance.
Abstract: Lactic acid bacteria (LAB) constitute a group of gram-positive bacteria united by a constellation of morphological, metabolic, and physiological characteristics The general description of the bacteria included in the group is gram-positive, nonsporing, nonrespiring cocci or rods, which produce lactic acid as the major end product during the fermentation of carbohydrates The LAB term is intimately associated with bacteria involved in food and feed fermentation, including related bacteria normally associated with the (healthy) mucosal surfaces of humans and animals The boundaries of the group have been subject to some controversy, but historically the genera Lactobacillus, Leuconostoc, Pediococcus, and Streptococcus form the core of the group Taxonomic revisions of these genera and the description of new genera mean that LAB could, in their broad physiological definition, comprise around 20 genera However, from a practical, food-technology point of view, the following genera are considered the principal LAB: Aerococcus, Carnobacterium, Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Oenococcus, Pediococcus, Streptococcus, Tetragenococcus, Vagococcus, and Weissella The genus Bifidobacterium, often considered in the same context as the genuine lactic acid bacteria and sharing some of their typical features, is phylogenetically unrelated and has a unique mode of sugar fermentation The classification of lactic acid bacteria into different genera is largely based on morphology, mode of glucose fermentation, growth at different temperatures, configuration of the lactic acid produced, ability to grow at high salt concentrations, and acid or alkaline tolerance Chemotaxonomic markers such as fatty acid composition and constituents of the cell wall are also used in classification In addition, the present taxonomy relies partly on true phylogenetic relationships,
995 citations
TL;DR: It is demonstrated that the yield of a growth process may be accurately computed by considering the relevant biochemistry of conversion reactions and the cytological implications of biosynthesis and growth.
915 citations
TL;DR: Recent work indicated that bacteria can also use futile cycles of potassium, ammonia, and protons through the cell membrane to dissipate ATP either directly or indirectly, and the utility of energy spilling in bacteria has been a curiosity.
810 citations
Cites background from "Molar growth yields and fermentatio..."
...Many streptococci and lactobacilli that were originally classified as homolactic produce acetate, formate, and ethanol when the rate of glucose fermentation is low (26, 97)....
[...]
...(26) noted that not even this correction could give YATP values as great as 32 g of cells per mol; Lactobacillus casei grown in glucose-limited continuous cultures had a YATP/MAX of only 24....
[...]
TL;DR: An overview of the following topics is given: main pathways of homo- and heterofermentation of hexoses, i.e. glycolysis, bifidus pathway, 6-phosphogluconate pathway; uptake and dissimilation of lactose (tagatose pathway); fermentation of pentoses and pentitols; alternative fates of pyruvate.
Abstract: The term “lactic acid bacteria” is discussed. An overview of the following topics is given: main pathways of homo- and heterofermentation of hexoses, i.e. glycolysis, bifidus pathway, 6-phosphogluconate pathway; uptake and dissimilation of lactose (tagatose pathway); fermentation of pentoses and pentitols; alternative fates of pyruvate, i.e. splitting to formate and acetate, CO2 and acetate or formation of acetoin and diacetyl; lactate oxidation; biochemical basis for the formation of different stereoisomers of lactate.
800 citations
References
More filters
3,422 citations
TL;DR: In this communication, a method is described which utilizes the reaction of acyl phosphates with hydroxylamine and the acyl part of the acid anhydride is converted into hydroxamic acid.
1,373 citations
TL;DR: From the laws of growth, a simple relation between the maintenance requirement, the growth yield and the growth rate is derived and is shown to be in good agreement with the available data.
Abstract: The variation, with growth rate, of the yield of organism from the substrate used as energy source is attributed to consumption of energy at a constant rate for cell maintenance. From the laws of growth, a simple relation between the maintenance requirement, the growth yield and the growth rate is derived. The relation is shown to be in good agreement with the available data. A distinction is made between 'observed' yield and 'true' yield of organisms. Values for maintenance energies and 'true growth yields' have been calculated from the data.
1,368 citations
TL;DR: The results suggest that, under anaerobic conditions, the yield of S. faecalis, S. cerevisiae and P. lindneri was proportional to the amount of ATP synthesized, which was compatible with the formation of approximately 4 mole ATP/mole glucose, 2 mole ATP-mole glycerol and 1 mole ATP /mole lactate.
Abstract: SUMMARY: When Streptococcus faecalis was grown anaerobically in a complex medium containing d-glucose, d-ribose or l-arginine as energy source the dry wt. of organism produced was proportional to the concentration of the energy source in the medium. However, S. faecalis will not grow in a defined medium with arginine as the energy source unless glucose is present at the same time. The anaerobic growth of both Saccharomyces cerevisiae and Pseudomonas lindneri was proportional to the concentration of glucose in the medium and the yield coefficient—defined as g. dry wt. organism/mole glucose—of the former was the same as that of S. faecalis grown upon glucose and approximately twice that of P. lindneri. Calculation of the g. dry wt. organism/mole adenosine triphosphate synthesized for these three organisms gave values ranging from 12.6 to 8.3 with an average of 10.5. These results suggest that, under anaerobic conditions, the yield of S. faecalis, S. cerevisiae and P. lindneri was proportional to the amount of ATP synthesized. When Propionibacterium pentosaceum was grown anaerobically with glucose, glycerol or dl-lactate as energy source there was, in all three cases, a linear relationship between the dry wt. of organisms produced and the concentration of the energy source in the medium. The values of the yield coefficients obtained were compatible with the formation of approximately 4 mole ATP/mole glucose, 2 mole ATP/mole glycerol and 1 mole ATP/mole lactate.
916 citations
TL;DR: Direct measurement of the metabolic changes in the intracellular carbohydrate of yeast has usually been restricted to the determination of total hydrolysable carbohydrate, that is to say, of reducing power after acid hydrolysis of a cell suspension.
Abstract: Direct measurement ofthe metabolic changes in the intracellular carbohydrate ofyeast has usually been restricted to the determination oftotal hydrolysable carbohydrate, that is to say, ofreducing power after acid hydrolysis of a cell suspension. The work of Pickett & Clifton (1943), or of Fales & Baumberger (1948), exemplifies this technique applied respectively to the aerobic and anaerobic metabolism of glucose by yeast. Clifton (1946) has reviewed studies in some ofwhich indirect methods were used: variation in carbon content, dry weight, and opacity have all been taken as indices of polysaccharide synthesis. Nickerson (1949) has taken the increase of dry weight of yeast during the aerobic metabolism of glucose as measuring, not merely synthesis of cell carbohydrate, but even synthesis of a particular polysaccharide, glycogen. Yeast, however, contains several other carbohydrates (see, for example, Neuberg, 1946): e.g. mannan, trehalose, and a 1:3-glucan insoluble in dilute acid or alkali. Ofthese trehalose (Pigman & Goepp, 1948), and glucan (Hassid, Joslyn & McCready, 1941) are only hydrolysed by drastic treatment which, when applied to yeast, might cause destruction of less stable sugars, such as the pentose derived from nucleotides and nucleic acids. In consequence, the determination even of total hydrolysable carbohydrate would seem, in principle, unsatisfactory. Schemes for fractionation of some of the constituents of yeast, followed by determination ofeach as reducing sugar after hydrolysis have been described, the latest being that of Payen (1949). These procedures frequently require large amounts ofmaterial and are excessively time-consuming. By determining carbohydrate colorimetrically with the anthrone reagent (Dreywood, 1946) we have been able to estimate the total carbohydrate of the yeast cell directly, and also to analyse separate fractions without lengthy hydrolysis. Fractionation was achieved by extracting the yeast with trichloroacetic acid, after which the extracted material was treated with alkali, and an alcohol precipitation carried out according to the method used by Good, Kramer & Somogyi (1933) for the determination of glycogen in animal tissue. The residue from these extractions formed a third fraction. Application of paper chromatography enabled this empirical procedure to be related to the known carbohydrate constituents of yeast.
811 citations