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1.
Summary The growth parameters of Acinetobacter calcoaceticus, relevant to its mass cultivation on acetate and ethanol, were determined in batch and continuous culture experiments. Acetic
acid exhibited a more powerful inhibitory effect on the growth rate than ethanol. In batch culture, the acetate component
of an acetate-ethanol substrate pair was preferentially utilized, but diauxic growth as such was not evident. The temperature
optimum for growth was in the region of 29°–36°C, and the cell yield did not change appreciably over this temperature range.
In carbon-limited chemostat cultures, the maximum specific growth rates on acetate and ethanol were 1.22 h−1 and 0.96 h−1 respectively, and the respective yield coefficients were 0.4 and 0.75. A high maintenance energy requirement was exhibited,
especially during acetate-limited growth. The respiratory quotient was dependent on the growth rate, the significance of which
is discussed.
Part of the material included in this paper was presented at the VIth International Fermentation Symposium, London, Ontario,
July 1980 相似文献
2.
B. J. Van Schie R. J. Rouwenhorst J. P. Van Dijken J. G. Kuenen 《Antonie van Leeuwenhoek》1989,55(1):39-52
Glucose metabolism has been studied in two strains ofAcinetobacter calcoaceticus. Strain LMD 82.3, was able to grow on glucose and possessed glucose dehydrogenase (EC 1.1.99.17). Glucose oxidation by whole
cells was stimulated by PQQ, the prosthetic group of glucose dehydrogenase. PQQ not only increased the rate of glucose oxidation
and gluconic acid production but also shortened the lag phase for growth on glucose.
Strain LMD 79.41 also possessed glucose dehydrogenase but was unable to grow on glucose. Batch cultures and carbon-limited
chemostat cultures growing on acetate in the presence of glucose oxidized the sugar to gluconic acid, which was not further
metabolized. However, after prolonged cultivation on mixtures of acetate and glucose, carbon-limited chemostat cultures suddenly
acquired the capacity to utilize gluconate. This phenomenon was accompanied by the appearance of gluconate kinase and a repression
of isocitrate lyase synthesis. In contrast to the starter culture, cells from chemostats which had been fully adapted to gluconate
utilization, were able to utilize glucose as a sole carbon and energy source in liquid and solid media. 相似文献
3.
A gas chromatographic method for the determination of aldose and uronic Acid constituents of plant cell wall polysaccharides 总被引:25,自引:14,他引:11
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A major problem in determining the composition of plant cell wall polysaccharides has been the lack of a suitable method for accurately determining the amounts of galacturonic and glucuronic acids in such polymers. A gas chromatographic method for aldose analysis has been extended to include uronic acids. Cell wall polysaccharides are depolymerized by acid hydrolysis followed by treatment with a mixture of fungal polysaccharide-degrading enzymes. The aldoses and uronic acids released by this treatment are then reduced with NaBH4 to alditols and aldonic acids, respectively. The aldonic acids are separated from the alditols with Dowex-1 (acetate form) ion exchange resin, which binds the aldonic acids. The alditols, which do not bind, are washed from the resin and then acetylated with acetic anhydride to form the alditol acetate derivatives. The aldonic acids are eluted from the resin with HCl. After the resin has been removed, the HCl solution of the aldonic acids is evaporated to dryness, converting the aldonic acids to aldonolactones. The aldonolactones are reduced with NaBH4 to the corresponding alditols, dried and acetylated. The resulting alditol acetate mixtures produced from the aldoses and those from the uronic acids are analyzed separately by gas chromatography. This technique has been used to determine the changes in composition of Red Kidney bean (Phaseolus vulgaris) hypocotyl cell walls during growth, and to compare the cell wall polysaccharide compositions of several parts of bean plants. Galacturonic acid is found to be a major component of all the cell wall polysaccharides examined. 相似文献
4.
A.B. Watts J. Beecher C.S. Whitcher J.A. Littlechild 《Biocatalysis and Biotransformation》2013,31(3):209-215
The assay for Baeyer-Villiger monooxygenase (BVMO) enzyme activity has relied to date on the spectrophotometric change observed on the oxidation of the nicotinamide cofactor during the enzymatic reaction. By analogy to the cyclohexanol catabolic pathway of Acinetobacter calcoaceticus NCIMB 9871, we have developed a specific colorimetric screening method that utilises an esterase to cleave the lactone that is formed in the BVMO reaction. When carried out in a non-buffered or weakly buffered system the resultant change in pH can be visually detected. This allows the rapid assaying and screening of BVMO enzymes. This has been demonstrated with cyclohexanone monooxygenase from A. calcoaceticus. The resultant colour change has been visualised with washed cell suspensions, individual bacterial colonies on Petri dishes and with semi-purified recombinant enzyme utilising Linbro dishes. 相似文献
5.
Cyanide condenses with aldoses at 25° in aqueous solution between pH 7.0–9.0 to produce aldononitriles in high yield. These nitriles may be reduced catalytically over palladium-barium sulfate (5%) at pH 4.2 ± 0.1 and 25° to yield the corresponding aldoses in 60–90% yield, depending on the structure of the nitrile. 1-Amino-1-deoxyalditols are produced in approximately 10% yield, and their formation is favored when hemiacetal formation is hindered in the parent aldose. Generally, the product epimeric aldoses can be separated from contaminating by-products and from each other by ion-exchange and adsorption chromatography. This procedure has been applied to the preparation of [1-13C]-enriched pentoses and hexoses. 相似文献
6.
The ratios of the oxidation rates of aldose sugars, determined in cell-free extracts of Acinetobacter calcoaceticus, vary with the strain and growth conditions used. Three distinct forms of glucose dehydrogenase with different substrate specificities, occurring in variable proportions in these extracts, are responsible for this effect. One form is the already known soluble glucose dehydrogenase, the other two forms are complexes containing enzyme and components of the respiratory chain. The proportions in which the enzyme forms are found in the cell-free extract correlate with the oxidative behaviour of whole cells with respect to aldose sugars. It is concluded, therefore, that the enzyme forms are not an artefact of the isolation procedure but that they exist as such in vivo. Since the two complexes can be converted into the soluble enzyme form, aldose dehydrogenase can, probably, be integrated in three different ways into the respiratory chain.The presence of glucose during growth does not stimulate aldose dehydrogenase production. This is not surprising since the enzyme has no function in carbon metabolism, except perhaps in strains growing on pentoses at high pH. Therefore, the physiological role of quinoprotein aldose dehydrogenase in this organism may be primarily in energy generation.Non-standard abbreviations quinoproteins
enzymes containing 2,7,9-tricarboxy-1 H-pyrrolo [2,3f] quinoline-4,5-dione (pyrrolo-quinoline quinone) as the coenzyme 相似文献
7.
This paper describes the effects of formate on fermentative hydrogen production by Enterobacter aerogenes by way of batch culture. When 20 mM formate was added to pH 6.3 and pH 5.8 E. aerogenes glucose cultures (formate culture) at the beginning of cultivation, hydrogen evolution through both glucose consumption and decomposition of the extrinsic formate occurred together, while hydrogen evolution occurred only through glucose consumption in the control cultures. The hydrogen evolution rates in the formate cultures were faster than in the control cultures, although cell growth and glucose consumption rates in the formate cultures were slower than the control cultures’. The decomposition rate of the extrinsic formate in the pH 5.8 formate culture was faster than in the pH 6.3 fomiate culture. The hydrogen yield from glucose in the pH 6.3 formate culture increased due to the increasing amount of the nicotinamide adenine dinucleotide for hydrogen production. 相似文献
8.
The regulation of the synthesis of the quinoprotein glucose dehydrogenase (EC 1.1.99.17) has been studied inAcinetobacter calcoaceticus LMD 79.41, an organism able to oxidize glucose to gluconic acid, but unable to grow on both compounds. Glucose dehydrogenase
was synthesized constitutively in both batch and carbon-limited chemostat cultures on a variety of substrates. In acetate-limited
chemostat cultures glucose dehydrogenase levels and the glucose-oxidizing capacity of whole cells were dependent on the growth
rate. They strongly increased at low growth rates at which the maintenance requirement of the cells had a pronounced effect
on biomass yield.
Cultures grown on a mixture of acetate and glucose in carbon and energy-limited chemostat cultures oxidized glucose quantitatively
to gluconic acid. However, during oxygen-limited growth on this mixture glucose was not oxidized and only very low levels
of glucose dehydrogenase were detected in cell-free extracts. After introduction of excess oxygen, however, cultures or washed
cell suspensions almost instantaneously gained the capacity to oxidize glucose at a high rate, by an as yet unknown mechanism. 相似文献
9.
A method is introduced which makes a continuous oxidation of glucose to glucose acid possible. This method is based on the auxiliary-substrate concept and co-metabolism, respectively. Micro-organisms (e.g. Acinetobacter calcoaceticus), which cannot assimilate glucose, but merely oxidize it, are grown continuously on a heterotrophic substrate (e.g. acetate). While growing they simultaneously synthesize gluconic acid. The productivity of the gluconic acid synthesis with a given strain depends on the dilution rate and the mixing proportion. Since growth and product synthesis are closely connected and growth yield is very much higher due to an auxiliary substrate effect in the presence of glucose than on the heterotrophic substrate alone, this method is suitable for SCP production as well. The productivity of gluconic acid production is controlled at a certain dilution rate by the mixing proportion of the growth substrate and glucose. 相似文献
10.
Candida utilis was grown on acetate in chemostat cultures that were, successively, carbon and ammonia-limited (30° C; pH 5.5). With carbon(acetate)-limited cultures, the specific rate of oxygen consumption (q
O
2) was not a linear function of the growth rate but was markedly stimulated at the higher dilution rates, thus effecting a marked decrease in the Y
O value. This increased respiration rate, and decreased yield value, correlated closely with a marked increase in the extracellular acetate concentration. Under ammonia-limiting conditions, very low Y
O values were found, generally comparable with those found with carbon-limited cultures growing at the higher dilution rates, but these varied markedly with the extracellular acetate concentration. Thus, when the unused acetate concentration was raised progressively from about 5 g/l to about 21 g/l, the Y
O value decreased non-linearly from 11.4 to 5.8. When the extracellular acetate concentration was further increased to 25 g/l, growth was inhibited and the culture washed out. This relationship between respiration rate and the extracellular concentration of unused acetate was also markedly influenced by the culture pH value. Thus, with a fixed extracellular acetate concentration (16±2g/l) and dilution rate (0.14 h–1), lowering the culture pH value progressively from 6.9 to 5.1 effected a marked and progressive increase in the respiration rate. Further lowering of the culture pH to 4.8, however, caused a complete collapse of respiration. In contrast to this situation, progressively lowering the pH value of an acetatelimited culture from 6.9 to 4.5 affected only slightly the culture respiration rate, and growth was possible even at a pH value of 2.5. These results are discussed in the context of the possible mechanisms whereby acetate exerts its toxic effect on the growth of C. utilis. 相似文献
11.
Summary The effect of three parameters (initial acetate concentration, temperature and pH) on the acetoclastic reaction was studied with the thermophilic methanogenic bacterium Methanosarcina sp. MSTA-1. The optimum temperature for growth ranged around 55° C, and optimum pH was 6.5–7.5, giving a minimum generation time of 12.6–13.9 h (µmax = 0.050–0.055 h–1) and a maximum value of the specific acetate consumption rate (q
infs
supps
) of 14–20 mmol/g cells per hour. Contrary to the methane yield, the growth yield was found to be dependent on culture conditions, especially on incubation temperature. Methanosarcina sp. MSTA-1 showed a low affinity for acetate substrate. Growth at 55° C and at constant pH 7 resulted in a K
m value and a threshold acetate concentration of 10.7 mM and 0.7 mM, respectively.
Offprint requests to: R. Moletta 相似文献
12.
Cells of Acinetobacter calcoaceticus 69-V could be energized by glucose oxidation after the growth on acetate, ethanol, hexanol and benzoate. The velocities of glucose oxidation-driven ATP syntheses were relatively constant in the range from pH 5.4 to 7.5. With decreasing pH values (7.0, 6.0, 5.4) ATP synthesis was inhibited more strongly by the action of 2,4-dinitrophenol and at the same pH value glucose oxidation was nearly unimpaired or inhibited more weakly. This finding is expressed by a decrease of the P/O ratios, indicating the uncoupling of the electron-transport phosphorylation by 2,4-dinitrophenol. The sensitivity towards this uncoupling effect was higher in ethanol-grown cells of Acinetobacter calcoaceticus 69-V than in hexanol- or acetate-grown cells. This increase in sensitivity was accompanied by a decrease of the ratio of saturated (mainly C16:0) to unsaturated (C16:1, C18:1) fatty acids in ethanol-grown cells compared with hexanol-grown ones. The knowledge of such differences in the susceptibility and its molecular background, e.g. possible substrate-induced changes of the fatty acid composition of the cytoplasmic membranes, should help elucidate mechanisms of poisoning by membrane-active hazardous chemicals and develop defence strategies. 相似文献
13.
Paul W. Behrens Scott E. Bingham Scot D. Hoeksema Deborah L. Cohoon John C. Cox 《Journal of applied phycology》1989,1(2):123-130
Chlorella vulgaris was grown photosynthetically in batch culture under nitrogen sufficiency or nitrogen limitation. The starch content of the
cells was measured as the amount of glucose released by enzymic hydrolysis of partially purified starch. Nitrogen sufficient
algae contained approximately 20% of their dry weight as starch, whereas in nitrogen limited cells starch comprised up to
55% of the cellular dry weight. Starch production was pH dependent; optimal production of starch was achieved between pH 7.5
and 8.0. Optimal growth of C. vulgaris occurred at pH 7.0. Carbon yield experiments showed that for every gram of carbon consumed 0.5 g of starch (glucose) could
be recovered.
author for correspondence 相似文献
14.
Current researches into the production of biochemicals from lignocellulosic feedstocks are focused on the identification and
engineering of individual microbes that utilize complex sugar mixtures. Microbial consortia represent an alternative approach
that has the potential to better exploit individual species capabilities for substrate uptake and biochemical production.
In this work, we construct and experimentally validate a dynamic flux balance model of a Saccharomyces cerevisiae and Escherichia coli co-culture designed for efficient aerobic consumption of glucose/xylose mixtures. Each microbe is a substrate specialist,
with wild-type S. cerevisiae consuming only glucose and engineered E. coli strain ZSC113 consuming only xylose, to avoid diauxic growth commonly observed in individual microbes. Following experimental
identification of a common pH and temperature for optimal co-culture batch growth, we demonstrate that pure culture models
developed for optimal growth conditions can be adapted to the suboptimal, common growth condition by adjustment of the non-growth
associated ATP maintenance of each microbe. By comparing pure culture model predictions to co-culture experimental data, the
inhibitory effect of ethanol produced by S. cerevisiae on E. coli growth was found to be the only interaction necessary to include in the co-culture model to generate accurate batch profile
predictions. Co-culture model utility was demonstrated by predicting initial cell concentrations that yield simultaneous glucose
and xylose exhaustion for different sugar mixtures. Successful experimental validation of the model predictions demonstrated
that steady-state metabolic reconstructions developed for individual microbes can be adapted to develop dynamic flux balance
models of microbial consortia for the production of renewable chemicals. 相似文献
15.
Since glucose can be oxidized but not assimilated by Acinetobacter calcoaceticus 69-V the question arose whether energy generated by glucose oxidation can help incorporate carbon from heterotrophic substrates and, if so, what the efficiency of ATP production is like. For this reason this species was grown in the chemostat on acetate. After having reached steady state conditions an increasing concentration of glucose was added. This led to an increase in the biomass level from about 0.4 g/g for growth on acetate alone to 0.6–0.65 g/g in the presence of glucose, independently of either the growth rate or the steepness of the glucose gradient used. This upper value approximates about the limit of the carbon conversion efficiency calculated for non-glycolytic substrates. Glucose was almost exclusively oxidized to gluconic acid, 2- and 5-ketogluconates, and pentose 5-phosphates were found only in traces. These results demonstrate that glucose functions as an additional energy source in Acinetobacter calcoaceticus 69-V. From the transient behaviour of biomass increase and the mixing proportion at which the maximum growth yield on acetate in the presence of glucose was obtained it followed that two mol of ATP must have been generated per mol of glucose oxidized. This property is discussed in terms of coupling glucose dehydrogenase with the respiratory chain.Abbreviations
G
ox
glucose oxidized to gluconic acid
-
G
t
amount of glucose necessary for complete substitution of S
d
-
S
o
inlet concentration of the limiting carbon substrate
-
S
a and S
d
assimilated and dissimilated part respectively of the carbon substrate
- PQQ
pyrrolo-quinoline-quinone
-
V
ATP
Ac
ATP gain from complete oxidation to CO2 of acetate (P/O=2)
-
V
ATP
Glc
ATP gain from oxidation of glucose to gluconic acid 相似文献
16.
The fatty acid composition of Acinetobacter calcoaceticus 69-V was determined under various growth conditions. Saturated, unsaturated, and hydroxy fatty acids with chain lengths of
12–18 carbon atoms predominated in the fatty acid profile. With acetate or propanol as growth substrates, the ratio of saturated
to unsaturated fatty acids varied with changes in the temperature. This was the only adaptive mechanism detected that compensated
for the physical effects of temperature alterations on the cell membranes. The fatty acid composition of A. calcoaceticus grown at 40 °C had a saturation degree of approximately 50%; after growth at 20 °C it was approximately 35%. In the presence
of a carbon and energy source, A. calcoaceticus was able to respond to temperature reductions under oxic conditions regardless of whether fatty acid biosynthesis was inhibited
or not. This suggests an aerobic mechanism of fatty acid biosynthesis and the involvement of a fatty acid desaturase system.
Addition of the non-growth substrate, glucose, helped the organism to adapt to lower temperature. The molecular mechanism
of the aid is not really understood. The oxidation of glucose could provide the desaturase either with electrons directly
via a pyrrolo-quinoline-quinone-linked glucose dehydrogenase or with NADH after fatty acid degradation has been initiated
by ATP generated by the oxidation of glucose.
Received: 19 June 1998 / Accepted: 28 December 1998 相似文献
17.
Jeong-Sam Koh Takashi Yamakawa Tohru Kodama Yasuji Minoda 《Bioscience, biotechnology, and biochemistry》2013,77(5):1411-1416
A soil microorganism, identified as Acinetobacter calcoaceticus KB-2, was cultivated on palm oil as a carbon source for cell production. This organism grew with a specific growth rate of l.lOh?1. The pH optimum for growth was between 6.5 and 7.0, and the temperature optimum was 39°C. Compared with other strains on water-insoluble substrates such as hydrocarbons and natural oils and fats so far reported, the cultivation time for this strain was short and the cell mass productivity was relatively high. More than 90% of the palm oil was assimilated by this strain, and the overall cell yield was 1.02 (g of cells/g of palm oil) after 8 hr cultivation with the concentration of 3% palm oil. 相似文献
18.
Hitomi Ohara Keiichiro Hiyama Toshiomi Yoshida 《Applied microbiology and biotechnology》1992,38(3):403-407
A chemostat culture was used for lactic acid fermentation with Streptococcus faecalis at various pH values (8.0, 7.0, 6.0, 5.5, 5.0) and glucose concentrations (10, 20, 30 g/l). At every pH value, the reciprocals of the specific consumption rate of glucose and the specific production rate of lactic acid were linearly correlated to the reciprocal of the specific growth rate. The product, lactic acid, caused non-competitive inhibition of the specific growth rate at every pH value. Moreover, it was found that the cell death rate was dependent on pH and lactic acid. The death rate was smallest at pH 7.0 and increased with increasing lactic acid concentration. The kinetic equations of growth and death are proposed in a broader pH range.
Correspondence to: H. Ohara 相似文献
19.
Growth and energetics of Leuconostoc oenos during cometabolism of glucose with citrate or fructose. 总被引:4,自引:1,他引:3
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The metabolic and energetic characterization of the growth of Leuconostoc oenos on glucose-citrate or glucose-fructose mixtures enables the potential role of this bacterium in the wine-making process to be ascertained. Moreover, mixotrophic conditions remain a suitable means for improving biomass productivities of malolactic starter cultures. When the malolactic bacterium L. oenos was grown in batch cultures on complex medium at pH 5.0 with glucose-citrate or glucose-fructose mixtures, enhancement of both the specific growth rate and biomass production yields was observed. While growth was possible on fructose as the sole source of energy, citrate alone did not allow subsequent biomass production. The metabolic interactions between the catabolic pathways of the glucose cosubstrates and the heterofermentation of hexoses led to an increased acetate yield as a result of modified NADH oxidation. However, the calculated global coenzyme regeneration showed that the reducing equivalent balance was never equilibrated. The stimulatory effects of these glucose cosubstrates on growth resulted from increased ATP synthesis by substrate-level phosphorylation via acetate kinase. While the energetic efficiency remained close to 10 g of biomass produced per mol of ATP, the increase in the specific growth rate and biomass production yields was directly related to the rate and yield of ATP generation. 相似文献
20.
Yung-Hun Yang Christopher J. Brigham Charles F. Budde Paolo Boccazzi Laura B. Willis Mohd Ali Hassan Zainal Abidin Mohd Yusof ChoKyun Rha Anthony J. Sinskey 《Applied microbiology and biotechnology》2010,87(6):2037-2045
We employed systematic mixture analysis to determine optimal levels of acetate, propionate, and butyrate for cell growth and
polyhydroxyalkanoate (PHA) production by Ralstonia eutropha H16. Butyrate was the preferred acid for robust cell growth and high PHA production. The 3-hydroxyvalerate content in the
resulting PHA depended on the proportion of propionate initially present in the growth medium. The proportion of acetate dramatically
affected the final pH of the growth medium. A model was constructed using our data that predicts the effects of these acids,
individually and in combination, on cell dry weight (CDW), PHA content (%CDW), PHA production, 3HV in the polymer, and final
culture pH. Cell growth and PHA production improved approximately 1.5-fold over initial conditions when the proportion of
butyrate was increased. Optimization of the phosphate buffer content in medium containing higher amounts of butyrate improved
cell growth and PHA production more than 4-fold. The validated organic acid mixture analysis model can be used to optimize
R. eutropha culture conditions, in order to meet targets for PHA production and/or polymer HV content. By modifying the growth medium
made from treated industrial waste, such as palm oil mill effluent, more PHA can be produced. 相似文献