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1.
Claus Schnarrenberger 《Planta》1990,181(2):249-255
When green leaves of spinach (Spinacia oleracea L.) were surveyed for the presence of hexokinases which utilize glucose, fructose and-or mannose as a substrate, four kinases
could be distinguished by their order of elution during chromatography on diethylaminoethyl (DEAE)-cellulose: (i) a hexokinase
I with a specificity for fructose, glucose, and mannose, (ii) a fructokinase I with a specificity for fructose, (iii) a hexokinase
II with a specificity for glucose, fructose and mannose, and (iv) a fructokinase II with a specificity for fructose. Hexokinases
I and II had high apparent Km values for fructose (8 and 15 mM, respectively) and medium or low apparent Km values for glucose (150 and 18 μM, respectively) and mannose (18 and 15 μM, respectively). Maximal velocities were highest
with fructose, medium with glucose and lowest with mannose. That hexokinases I and II used several sugars as substrate was
concluded (i) from their identical elution profiles during enzyme separation and (ii) because their activities with two or
three sugars at a time was always lower than the sum of activities with one substrate, indicating competition of the sugars
for the reaction with the enzymes. Fructokinases I and II were very specific for fructose (85 and 140 μM, respectively) and
had only little, if any, activity with glucose or mannose. All kinases showed varying degrees of activity with nucleoside
triphosphates other than ATP. In the presence of all three sugars, hexokinases I and II were considerably more active with
ATP than with uridine-, cytidine-, and guanosine 5'-triphosphate (UTP, CTP, GTP) except that, in the presence of glucose,
hexokinase I was almost as active with UTP as with ATP. In the presence of fructose, fructokinase I exhibited highest activity
with GTP and a gradually decreasing level of activity with CTP, UTP, and ATP. The activities in the presence of the other
two sugars were highest with ATP. Fructokinase II was most active with ATP and fructose and progressively less active with
GTP, UTP, and CTP. Cell fractionation by isopycnic density-gradient centrifugation or differential centrifugation indicated
that fructokinase II was associated with chloroplasts, hexokinase II with mitochondria, and the other two kinases with the
non-particulate cell fraction. In green leaves of pea (Pisum sativum L.), only a hexokinase (II) and fructokinase (II) were present. Corn (Zea mays L.) leaves exhibited only very low hexokinase activity.
Dedicated to Prof. Dr. Hans Mohr on the occasion of his 60th birthday 相似文献
2.
The xylem of Antiaris africana contains sucrose, starch, glucose,fructose, maltose, and raffinose. Sucrose and starch are themost abundant carbohydrates. Glucose and fructose occur in relativelyequal amounts while maltose and raffinose are the least abundant.Raffinose disappears from the xylem during the dry season, justbefore leaf fall. The pattern of seasonal variation in the individualsugars and starch is similar. There is generally a peak at leaffall and a depletion of these reserves at new flush. Accumulationof carbohydrates during leaf fall occurs first in the youngestxylem (i.e. the 02-cm segment). The youngest xylem alsoaccumulates the greatest amount of reserve sugars and starch.The concentrations of the sugars decrease inwards until theybegin to rise after the 46-cm segment. There is, however,no such rise in the concentration of starch. The dry-mattercontents increase inwards from the youngest xylem until theylevel out after the 46-cm segment. There is a rapid fallin the sucrose and starch contents of felled A. africana. Sucrosedropped by about 65 per cent and starch by about 73 per centin the first 10 days after felling. The levels of other sugarsdecreased gradually except for glucose and fructose which initiallyrose and then fell. Glucose and maltose could still be detectedon the 68th day after felling. 相似文献
3.
Several carbohydrates were tested for their ability to stimulate last instar Heliothis zea larvae to bite and, as a measure of nutritional value, for their ability to prolong the lives of H. zea larvae in the absence of a protein. Sucrose, fructose and glucose strongly stimulated biting. Maltose and sorbose were weakly stimulating, and mannitol, rhamnose, galactose, and lactose did not stimulate biting at the concentrations tested. Sucrose, fructose, mannitol, maltose, glucose, galactose, corn starch, and lactose all prolonged life, but larval longevity varied among these carbohydrates. Rhamnose did not prolong life, nor did sorbose, which was slightly toxic. When fructose, glucose, or mannitol replaced sucrose in a nutritionally complete defined diet containing protein, utilization efficiencies were minimally affected. When sorbose was substituted for sucrose, it did not cause mortality, but it did depress the efficiency of utilization significantly below that of a control diet that lacked any carbohydrate except cellulose powder.
Résumé L'étude a porté sur l'apitude de plusieurs carbohydrates à stimuler les morsures des chenilles du dernier stade de H. zea et à prolonger leur vie, (mesure de la valeur nutritive), en absence de protéines. Sucrose, fructose et glucose stimulent fortement les morsures. Maltose et sorbose ont été faiblement stimulants, et rhamnose, galactose, lactose et mannitol n'ont pas stimulé aux concentrations examinées. Sucrose, fructose, mannitol, maltose, glucose, galactose, amidon de maïs et lactose ont tous prolongé la vie, mais d'une façon différente suivant les carbohydrates.La rhamnose n'a pas prolongé la vie, tout comme le sorbose, qui s'est révélé légèrement toxique. Quand le fructose, le glucose ou le mannitol ont remplacé le sucrose dans un régime complètement défini contenant des protéines, la perturbation de l'efficacité d'utilisation a été minimale, mais la substitution du sorbose par le sucrose, bien qu'elle n'ait pas provoqué de mortalité, a donné une efficacité d'utilisation significativement plus faible qu'un témoin négatif ayant perdu tous les carbohydrates, à l'exception de poudre de cellulose.相似文献
4.
The Relationship between Sucrose Supply, Sucrose-cleaving Enzymes and Flower Abortion in Pepper 总被引:3,自引:1,他引:2
Abortion of pepper flowers depends on the light intensity perceivedby the plant and on the amounts of sucrose taken up by the flower(Aloni B, Karni L, Zaidman Z, Schaffer AA. 1996.Annals of Botany78: 163168). We hypothesize that changes in the activityof sucrose-cleaving enzymes within the flower ovary might beresponsible for the changes in flower abortion under differentlight conditions. In the present study we report that the activityof sucrose synthase, but not of cytosolic acid invertase, increasesin flowers of pepper plants which were exposed, for 2 d, toincreasing photosynthetically active radiation (PAR) in therange of 85400 µmol m-2s-1at midday. Sucrose synthaseactivity increased in parallel with the increasing concentrationsof starch in the flower ovary. Feeding flower explants, preparedfrom 3-d-predarkened plants, with 100 mM sucrose for 24 h, causeda 23% increase in reducing sugars and a 2.5-fold increase instarch concentration, compared with explants fed with buffer.Likewise, feeding explants of pepper flowers with sucrose, glucose,fructose and also mannitol increased the sucrose synthase activityin the ovaries. Concomitantly, sucrose, glucose and fructose,but not mannitol, reduced the abortion of flower explants. Itis suggested that sucrose entry into the flower increases theflower sink activity by inhibiting abscission and inducing metabolicchanges, thus enhancing flower set. Pepper; Capsicum annuum L.; abscission; light; pepper flowers; sucrose; glucose; fructose; starch; acid invertase; sucrose synthase 相似文献
5.
The choice of "black rats", Rattus rattus L ., for common sugars - sucrose, jaggery, glucose, fructose and lactose are described. In laboratory colonies, the sugars were preferred in the order glucose > sucrose > jaggery > fructose > lactose; but in another sequence - sucrose > jaggery > glucose > fructose > lactose, in the free living colonies. The discrepancy is accounted for by the characteristics of sugars which influence consummatory behaviour in the two situations. 相似文献
6.
Earl D. Mitchell Becky B. Johnson Tina Whittle 《In vitro cellular & developmental biology. Plant》1980,16(10):907-912
Summary Cotton callus and suspension cultures developed from a cotton variety susceptible toXanthomonas malvacearum (E. F. Sm.) Dow, were grown on chemically defined media that contained one of the carbohydrate sources: 3% sucrose, 3% lactose,
3% maltose, 3% fructose, and 3% glucose. All cells were maintained on a medium with sucrose as the carbohydrate and subsequently
transferred to media containing the above carbohydrates. Sucrose was the best carbon source for a high growth rate; however,
cells growing on glucose, which was almost as good as sucrose, and cells growing on lactose did not turn brown when they reached
the stationary phase of growth. A crude extract from callus tissue growing on lactose has a fivefold increase in β-galactosidase
[EC 3.21.23] activity as compared with the extract from callus tissue growing on sucrose. When callus tissue growing on lactose
was transferred tomedium containing sucrose, β-galactosidase activity decreased to the level as measured in cells maintained
on sucrose. Callus cells growing on a lactose medium showed staining when treated with 5-bromo-4-chloro-3-indolyl β-D-galactopyranoside
in which very heavy granular stains appeared. Cells growing on sucrose did not show the histochemical staining. These observations
suggest that β-galactosidase is induced in cotton callus tissue that has been transferred from a medium containing sucrose
to a medium containing lactose.
This is journal article J-3704 of the Oklahoma Agricultural Experiment Station. The research was supported in part by a Presidential
Challenge Grant from Oklahoma State University and the Oklahoma Agricultural Experiment Station. 相似文献
7.
Paula Alayón-Luaces Eduardo A. Pagano Luis A. Mroginski Gabriel O. Sozzi 《Plant Cell, Tissue and Organ Culture》2010,101(1):1-10
Sucrose presence and concentration modulated in different ways and to different extents the activity of six plant glycoside
hydrolases (PGHs) extracted from apple callus cultures, both in the water soluble fraction (WS-F) and in the NaCl-released
fraction (NaCl-F). β-d-Glucosidase activity increased because of sucrose starvation and the addition of sucrose decreased both WS-F and NaCl-F β-d-glucosidase from calli grown in a Murashige and Skoog’s basal medium with (MSH) or without (MS0) plant growth regulators
(PGRs). WS-F and NaCl-F α-l-arabinofuranosidase, NaCl-F β-d-galactosidase and NaCl-F β-d-xylosidase activity reached a maximum when 0.045 M sucrose was added to the MS0 medium with an ensuing decline at higher
sucrose concentrations. α-d-Galactosidase and α-d-xylosidase activity reached a maximum when 0.045 M sucrose was supplied and did not decline significantly in 0.09 M sucrose-supplied
calli. When the effects of PGR presence or absence were analysed, NaCl-F β-d-glucosidase, α-d-galactosidase, β-d-galactosidase, α-d-xylosidase and β-d-xylosidase activities were found to be higher in MS0 than in MSH. To assess whether sugar effects were sucrose-specific,
other sugars (glucose, fructose, galactose, maltose, lactose, raffinose, sorbitol and mannitol) were tested, with or without
PGR supplementation. In general, sugar alcohols (mannitol, sorbitol) and some monosaccharides (fructose and glucose in particular)
were better inducers of NaCl-F α-l-arabinofuranosidase, β-d-galactosidase and β-d-xylosidase activity than disaccharides (sucrose, maltose, and lactose) or the trisaccharide raffinose. This trend was not
widespread to all PGHs assessed since sucrose-supplemented calli displayed higher NaCl-F α-d-galactosidase than those supplemented with glucose, galactose, sorbitol or mannitol. These results show that sugars supplied
to callus tissue cultures as a carbon source can also modulate PGH activity. Modulation is different for each PGH, sugar-specific
and, at least in the case of sucrose, concentration-dependent. Results also suggest the existence of regulatory interactions
between PGRs and sugars as part of an intricate sensing and signalling network. Combination of PGR, sugar type and concentration
should be taken into account to maximize each PGH activity for further enzyme studies. 相似文献
8.
Anaerobic carbohydrate metabolism in wheat and barley, two anoxia-intolerant cereal seeds 总被引:5,自引:1,他引:4
Perata Pierdomenico; Guglielminetti Lorenzo; Alpi Amedeo 《Journal of experimental botany》1996,47(8):999-1006
Cereals such as barley and wheat are unable to germinate underanoxic conditions. Data are presented on the utilization ofthe soluble sugars present in the dry seed of wheat and barleykept under strict anoxia, together with the status of the enzymesinvolved in the metabolism of carbohydrates. The amount of glucose, fructose, and sucrose decreases duringthe anaerobic treatment, indicating that carbohydrate metabolismtakes place in the seeds of wheat and barley kept under anoxicconditions. The analysis of the enzymes involved in the metabolism of carbohydratesshows that the enzymatic set needed to convert sucrose, glucose,and fructose to glucose-6P is present in the anaerobic seeds.Sucrose degradation seemingly occurs through a sucrose synthasepathway with nucleoside diphosphate kinase involved in the cyclingof urydilates. However, the activity of sucrose synthase, glucokinase,and fructokinase, all strongly induced in rice, an anoxia-tolerantcereal, are almost unaffected or even depressed in the two cerealseeds under investigation. The comparison of the results obtained and described in thispaper with the published data on the metabolism of carbohydratesin rice, indicate that the anoxia-intolerant species would rapidlysuffer and eventually die from sugar starvation if kept underanoxia for a relatively prolonged length of time (48d). Key words: Anoxia, cereal seed, carbohydrate metabolism 相似文献
9.
Antti Vuolanto Ossi Pastinen Hans E. Schoemaker Matti Leisola 《Biocatalysis and Biotransformation》2013,31(4):235-240
We describe novel tetrose isomerizations and C-2 epimerizations by the industrially important d -xylose ketol-isomerase (E.C.5.3.1.5) with both the d - and l -forms of the sugars. We further show that in addition to isomerization to d -fructose, d -glucose is slowly C-2 epimerized to d -mannose. The formation rate of the C-2 epimer was 0.03 mg mg m 1 min m 1 from d -glucose, 0.56 mg mg m 1 min m 1 from d -arabinose and 3.0 mg mg m 1 min m 1 from d -erythrose. The equilibria of the reaction products as a function of temperature were measured for threose/erythrulose/erythrose, arabinose/ribulose/ ribose and glucose/fructose/mannose. 相似文献
10.
Mahmoud Tahoun Osama Shata Reda Mashaley Samir Abou-Donia 《Applied microbiology and biotechnology》1986,24(3):235-239
Summary An investigation was made of the effects of temperature and of mono- and disaccharides on lipids, biomass, odd-chain and unsaturated fatty acids production of Candida lipolytica. With different sugars as carbon source at 30°C, the order for biomass production was: fructose > glucose > sucrose > lactose > galactose, while lipids production/g biomass decreased as follows: lactose, sucrose, galactose, fructose and glucose. On the other hand, the odd-chain fatty acids contents decreased in the following order: fructose, lactose, glucose, sucrose and galactose. Lowering the temperature of cultivation to 15°C, biomass, lipids and unsaturated fatty acids decreased. However, a notable decrease in the content of odd-chain fatty acids was detected. 相似文献
11.
In the present study, a simple and sensitive photo‐induced chemiluminescence (CL) method for the quantitation of reducing sugars, including fructose, glucose, sucrose and lactose, was developed. This method was based on the on‐line photocatalytic reaction of the reducing sugars, using a home‐made photoreactor consisting of PTEF tube helically coiling around a high‐pressure mercury UV lamp. Reducing sugars were detected by direct CL emission resulting from the reaction between the photoproducts and luminol. To maximize the signal intensity, the effects of irradiation time, flow rate, luminol concentration, buffer pH and concentration were tested. Under optimum conditions, the linear dynamic ranges were all 0.36–18 mg/L and the relative standard deviations (RSDs) were 1.8–2.3%, with limits of detection (3σ) of 0.06 mg/L for fructose, glucose, sucrose and lactose. Finally, interference effects from ascorbic acid, amino acids (alanine, glycine, serine, leucine and methionine) and some metal ions and anions were also investigated. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
12.
Modeling sucrose hydrolysis in dilute sulfuric acid solutions at pretreatment conditions for lignocellulosic biomass 总被引:1,自引:0,他引:1
Agricultural and herbaceous feedstocks may contain appreciable levels of sucrose. The goal of this study was to evaluate the survivability of sucrose and its hydrolysis products, fructose and glucose, during dilute sulfuric acid processing at conditions typically used to pretreat lignocellulose biomass. Solutions containing 25g/l sucrose with 0.1-2.0% (w/w) sulfuric acid concentrations were treated at temperatures of 160-200 degrees C for 3-12min. Sucrose was observed to completely hydrolyze at all treatment conditions. However, appreciable concentrations of fructose and glucose were detected and glucose was found to be significantly more stable than fructose. Different mathematical approaches were used to fit the kinetic parameters for acid-catalyzed thermal degradation of these sugars. Since both sugars may survive dilute acid pretreatment, they could provide an additional carbon source for production of ethanol and other bio-based products. 相似文献
13.
Changes in Sugar Content during Cold Acclimation and Deacclimation of Cabbage Seedlings 总被引:4,自引:0,他引:4
The relationship between freezing tolerance and sugar contentin cabbage seedlings was investigated. Seedlings exposed tonon-freezing low temperature (5 °C) acquired freezing tolerancedown to -6 °C. The degree of freezing tolerance increasedwith duration of exposure to low temperature (up to 10 d). Sucrose,glucose, fructose and myo -inositol were detected as solublesugars in cabbage leaves, and all soluble sugars, except formyo -inositol, and starch increased gradually during cold acclimationsuch that their levels were positively correlated with the degreeof freezing tolerance. The induced freezing tolerance was attributednot to ontogenetic changes but to cold acclimation. However,the induced freezing tolerance was lost after only 1 d of deacclimationat control temperatures, and this change was associated witha large reduction in sugar content. These results reveal that the sugar content of cabbage leavesis positively correlated with freezing tolerance. Brassica oleracea L.; cabbage; cold acclimation; deacclimation; freezing tolerance; sugars 相似文献
14.
J. Dynesen H. P. Smits L. Olsson J. Nielsen 《Applied microbiology and biotechnology》1998,50(5):579-582
When Saccharomyces cerevisiae are grown on a mixture of glucose and another fermentable sugar such as sucrose, maltose or galactose, the metabolism is
diauxic, i.e. glucose is metabolized first, whereas the other sugars are metabolized when glucose is exhausted. This phenomenon
is a consequence of glucose repression, or more generally, catabolite repression. Besides glucose, the hexoses fructose and
mannose are generally also believed to trigger catabolite repression. In this study, batch fermentations of S. cerevisiae in mixtures of sucrose and either glucose, fructose or mannose were performed. It was found that the utilization of sucrose
is inhibited by concentrations of either glucose or fructose higher than 5 g/l, and thus that glucose and fructose are equally
capable of exerting catabolite repression. However, sucrose was found to be hydrolyzed to glucose and fructose, even when
the mannose concentration was as high as 17 g/l, indicating, that mannose is not a repressing sugar. It is suggested that
the capability to trigger catabolite repression is connected to hexokinase PII, which is involved in the in vivo phosphorylation
of glucose and fructose.
Received: 5 May 1998 / Received revision: 3 August 1998 / Accepted: 8 August 1998 相似文献
15.
Sugar Absorption and Sucrose Inversion by Excised Tomato Roots 总被引:3,自引:0,他引:3
The growth of excised tomato roots in sucrose is accompaniedby the appearance in the medium of glucose and fructose. Thequantitative relations between this appearance of glucose andfructose in the medium, total sugar absorption by the roots,and the decrease in the sucrose concentration of the mediumdo not suggest any causal relationship between sucrose uptakeand glucose and fructose appearance in the medium. Excised tomato roots exhibit surface invertase activity witha pH optimum at 4.04.4. Alterations of external pH, whichdid not affect sucrose absorption, drastically altered the levelsof glucose and fructose appearing in the medium. Glucose is preferentially absorbed from mixtures of glucoseand fructose, and by adjustment of the ratio of the two sugars,a mixture can be obtained from which equimolar absorption ofthe two sugars occurs. Root growth in this mixture is, however,very poor compared with that occurring in presence of sucrose. The results are discussed in the light of earlier studies onsucrose uptake by cultured tomato roots. 相似文献
16.
Amaretti A Tamburini E Bernardi T Pompei A Zanoni S Vaccari G Matteuzzi D Rossi M 《Applied microbiology and biotechnology》2006,73(3):654-662
The utilization of mono-, di-, and oligosaccharides by Bifidobacterium adolescentis MB 239 was investigated. Raffinose, fructooligosaccharides (FOS), lactose, and the monomeric moieties glucose and fructose were used. To establish a hierarchy of sugars preference, the kinetics of growth and sugar consumption were determined on individual and mixed carbohydrates. On single carbon sources, higher specific growth rates and cell yields were attained on di- and oligosaccharides compared to monosaccharides. Analysis of the carbohydrates in steady-state chemostat cultures, growing at the same dilution rate on FOS, lactose, or raffinose, showed that monomeric units and hydrolysis products were present. In chemostat cultures on individual carbohydrates, B. adolescentis MB 239 simultaneously displayed α-galactosidase, β-galactosidase, and β-fructofuranosidase activities on all the sugars, including monosaccharides. Glycosyl hydrolytic activities were found in cytosol, cell surface, and growth medium. Batch experiments on mixtures of carbohydrates showed that they were co-metabolized by B. adolescentis MB 239, even if different disappearance kinetics were registered. When mono-, di-, and oligosaccharides were simultaneously present in the medium, no precedence for monosaccharides utilization was observed, and di- and oligosaccharides were consumed before their constitutive moieties. 相似文献
17.
Matthias Laska Edith Carrera Sanchez Ernesto Rodriguez Luna 《Primates; journal of primatology》1998,39(1):91-96
The purpose of the present study was to determine relative taste preferences for five food-associated sugars inAteles geoffroyi. Using two-solution choice tests of brief duration (5 min) four adult spider monkeys were given the choice between all binary
combinations of sucrose, fructose, glucose, lactose, and maltose presented in equimolar concentrations of 20, 50, 100, and
200 mM respectively. Preferences for individual sugars were stable across the concentrations tested and indicate an order
of relative effectiveness (sucrose>fructose>glucose≥lactose≥maltose) which is similar to results obtained with the same method
in the squirrel monkey and to findings on relative sweetness in man. These results support the assumption that the order of
relative effectiveness of the sugars under investigation found in the present study may represent a general pattern of preference
in frugivorous and perhaps all primates. 相似文献
18.
Sugar-induced adventitious roots in<Emphasis Type="Italic"> Arabidopsis</Emphasis> seedlings 总被引:3,自引:0,他引:3
The effects of sugars on root growth and on development of adventitious roots were analyzed in Arabidopsis thaliana. Seeds were sown on agar plates containing 0.0–5.0% sugars and placed vertically in darkness (DD) or under long day (LD,
16 h:8 h) conditions, so that the seedlings were constantly attached to the agar medium. In the sucrose-supplemented medium,
seedlings showed sustained growth in both DD and LD. However, only dark-grown seedlings developed adventitious roots from
the elongated hypocotyl. The adventitious roots began to develop 5 days after imbibition and increased in number until day 11.
They could, however, be initiated at any position along the hypocotyl, near the cotyledon or the primary root. They were initiated
in the pericycle in the same manner as ordinary lateral roots. Sucrose, glucose and fructose greatly stimulated the induction
of adventitious roots, but mannose or sorbitol did not. Sucrose at concentrations of 0.5–2.0% was most effective in inducing
adventitious roots, although 5.0% sucrose suppressed induction. Direct contact of the hypocotyl with the sugar-supplemented
agar medium was indispensable for the induction of adventitious roots.
Electronic Publication 相似文献
19.
Twenty strains of Streptococcus bovis grew more slowly on lactose (1.21 ± 0.12 h−1) than on glucose (1.67 ± 0.12 h−1), and repeated transfers or prolonged growth in continuous culture (more than 200 generations each) did not enhance the growth
rate on lactose. Lactose transport activity was poorly correlated with growth rate, and slow growth could not be explained
by the ATP production rate (catabolic rate). Batch cultures growing on lactose always had less␣intracellular fructose 1,6-bisphosphate
(Fru1,6P
2) than cells growing on glucose (6.6 mM compared to 16.7 mM), and this difference could be explained by the pathway of carbon
metabolism. Glucose and the glucose moiety of lactose were metabolized by the Embden-Meyerhoff-Parnas (EMP) pathway, but the
galactose moiety of lactose was catabolized by the tagatose pathway, a scheme that by-passed Fru1,6P
2. A mutant capable of co-metabolizing lactose and glucose grew more rapidly when glucose was added, even though the total
rate of hexose fermentation did not change. Wild-type S. bovis grew rapidly with galactose and melibiose, but these galactose-containing sugars were activated by galactokinase and catabolized
via EMP. On the basis of these results, rapid glycolytic flux through the EMP pathway is needed for the rapid growth (more
than 1.2 h−1) of S.␣bovis.
Received: 3 June 1997 / Received revision: 10 September 1997 / Accepted: 6 January 1998 相似文献
20.
Gustavo Graciano Fonseca Nuno Miguel Barbosa de Carvalho Andreas Karoly Gombert 《Applied microbiology and biotechnology》2013,97(11):5055-5067
The yeast Kluyveromyces marxianus has been pointed out as a promising microorganism for a variety of industrial bioprocesses. Although genetic tools have been developed for this yeast and different potential applications have been investigated, quantitative physiological studies have rarely been reported. Here, we report and discuss the growth, substrate consumption, metabolite formation, and respiratory parameters of K. marxianus CBS 6556 during aerobic batch bioreactor cultivations, using a defined medium with different sugars as sole carbon and energy source, at 30 and 37 °C. Cultivations were carried out both on single sugars and on binary sugar mixtures. Carbon balances closed within 95 to 101 % in all experiments. Biomass and CO2 were the main products of cell metabolism, whereas by-products were always present in very low proportion (<3 % of the carbon consumed), as long as full aerobiosis was guaranteed. On all sugars tested as sole carbon and energy source (glucose, fructose, sucrose, lactose, and galactose), the maximum specific growth rate remained between 0.39 and 0.49 h?1, except for galactose at 37 °C, which only supported growth at 0.31 h?1. Different growth behaviors were observed on the binary sugar mixtures investigated (glucose and lactose, glucose and galactose, lactose and galactose, glucose and fructose, galactose and fructose, fructose and lactose), and the observations were in agreement with previously published data on the sugar transport systems in K. marxianus. We conclude that K. marxianus CBS 6556 does not present any special nutritional requirements; grows well in the range of 30 to 37 °C on different sugars; is capable of growing on sugar mixtures in a shorter period of time than Saccharomyces cerevisiae, which is interesting from an industrial point of view; and deviates tiny amounts of carbon towards metabolite formation, as long as full aerobiosis is maintained. 相似文献