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1.
An indigenously isolated strain of Tolypocladium inflatum, when grown as a suspension culture in semi-synthetic and synthetic media, produced cyclosporin A. Biosynthesis of this well-known
immunosuppressive agent was found to be influenced heavily by the external addition of the amino acid constituents of the
molecule. In synthetic media, L-leucine and L-valine were found to act as strong inducers of drug production. L-Valine increased the specific production of cyclosporin A by 75% in semi-synthetic medium and by ten times in synthetic medium
compared to an unsupplemented control culture. D-Valine had no stimulating effect on the production. The presence of amino acids in the exponential growth phase ensured optimal
production, as was indicated in the experiment in which L-valine was added at different times; 4 g/l was the optimum concentration of exogenous L-valine. On the other hand, exogenous sarcosine and L-methionine tended to diminish drug production.
Received: 23 October 1995/Received revision: 23 January 1996/Accepted: 29 January 1996 相似文献
2.
C. G. Hounsa J. M. Aubry H. C. Dubourguier J. P. Hornez 《Applied microbiology and biotechnology》1996,45(6):764-770
The expression of a recombinant pectate lyase from Bacteroides thetaiotaomicron strain 217 was studied in Escherichia coli strain HB101(pBT4). First, two sets of complete 24 factorial designs were used to evaluate the influences of casamino acids, glucose, magnesium, calcium, tetracycline, ampicillin,
tryptophan and MOPS buffer on pectate lyase production in a basal medium. While casamino acids, glucose and magnesium were
found to be the prevalent factors, the presence of tetracycline, ampicillin and MOPS buffer were necessary for the reproducibility
of the process, probably by increasing the plasmid stability. Secondly, application of the Doehlert design, a response-surface
methodology, allowed a good prediction of pectate lyase production according to the variation in glucose and magnesium concentrations.
This optimization strategy allowed the production of biomass and recombinant pectate lyase respectively to be increased from
0.2 g l-1 to 1.9 g l-1 (dry weight) and from 10 units ml-1 to 210 units ml-1 within 24 h at 30°C in shake flasks.
Received: 26 July 1995/Received revision: 22 January 1996/Accepted: 29 January 1996 相似文献
3.
Yang-Ming Lo Shang-Tian Yang David B. Min 《Applied microbiology and biotechnology》1997,47(6):689-694
Although available kinetic data provide a useful insight into the effects of medium composition on xanthan production by
Xanthomonas campestris, they cannot account for the synergetic effects of carbon (glucose) and nitrogen (yeast extract) substrates on cell growth
and xanthan production. In this work, we studied the effects of the glucose/yeast-extract ratio (G/YE) in the medium on cell
growth and xanthan production in various operating modes, including batch, two-stage batch, and fed-batch fermentations. In
general, both the xanthan yield and specific production rate increased with increasing G/YE in the medium, but the cell yield
and specific growth rate decreased as G/YE increased. A two-stage batch fermentation with a G/YE shift from an initial low
level (2.5% glucose/0.3% yeast extract) to a high level (5.0% glucose/0.3% yeast extract) at the end of the exponential growth
phase was found to be preferable for xanthan production. This two-stage fermentation design both provided fast cell growth
and gave a high xanthan yield and xanthan production rate. In contrast, fed-batch fermentation with intermittent additions
of glucose to the fermentor during the stationary phase was not favorable for xanthan production because of the relatively
low G/YE resulting in low xanthan production rate and yield. It is also important to use a moderately high yeast extract concentration
in the medium in order to reach a high cell density before the culture enters the stationary phase. A high cell density is
also important to the overall xanthan production rate.
Received: 30 September 1996 / Received revision: 21 January 1997 / Accepted: 10 February 1997 相似文献
4.
The time courses of growth and rosmarinic acid production by Lavandula vera MM cell suspension were investigated. The uptake of the main nutrients (sucrose, nitrogen, phosphorus, K, Ca, Mg) was followed
during cultivation and the data on the physiology of the L. vera MM cell culture are presented. It was established that the cell culture synthesizes rosmarinic acid during the linear phase
of growth for a relatively short period (between the 4th and 8th days of cultivation). The influence of sucrose concentration
in the nutrient medium on cell growth and accumulation of rosmarinic acid by L. vera MM cell culture was investigated. The results showed that 7% sucrose in the nutrient medium ensured a steady growth of the
cell suspension and increased the yield of rosmarinic acid (29.2 g/l dry biomass and 507.5 mg/l rosmarinic acid compared to
13.0 g/l dry biomass and 68.6 mg/l rosmarinic acid for the control cultivation with 3% sucrose).
Received: 17 September 1996 / Received revision: 31 January 1997 / Accepted: 1 February 1997 相似文献
5.
J. Planas P. Ra˚dström F. Tjerneld B. Hahn-Hägerdal 《Applied microbiology and biotechnology》1996,45(6):737-743
In order to enhance the productivity of lactic acid and reduce the end-product inhibition of fermentation, the partitioning
and growth of four different strains of lactic acid bacteria in three different aqueous two-phase systems were studied. Polyethyleneglycol/
dextran, polyethyleneglycol/hydroxypropyl starch polymer (HPS), and a random copolymer of ethylene oxide and propylene oxide
(EO-PO)/HPS were used as polymer systems. One strain each of Lactococcus lactis subsp. lactis and of Lactobacillus delbrueckii subsp. delbrueckii partitioned completely to the interface and bottom phase in two-phase systems with low polymer concentrations of EO-PO/HPS100
and EO-PO/ HPS200. The growth and production of lactic acid by two of three L. lactis strains in a two-phase system with 5.5% (w/w) EO-PO and 12.0% (w/w) HPS100 were reduced by less than 10% compared with a
reference fermentation in a normal growth medium. The viability of L. lactis subsp. lactis ATCC 19435 was maintained for at least 50 h and with four top-phase replacements during extractive fermentation in the EO-PO/HPS100
system. Moreover, when cell density reached the stationary phase in the first extractive fermentation, the lactate production
in this aqueous two-phase system was maintained.
Received: 2 October 1995/Received revision: 16 January 1996/Accepted: 22 January 1996 相似文献
6.
G. Miksch R. Neitzel E. Fiedler K. Friehs E. Flaschel 《Applied microbiology and biotechnology》1997,47(2):120-126
Cultivation conditions for the extracellular production of a hybrid β-glucanase from Bacillus were established by using Escherichiacoli JM109 carrying the plasmid pLF3. This plasmid contained a novel secretion system consisting of the kil gene (killing protein) of plasmid ColE1 under the stationary-phase promoter of either the fic or the bolA gene, an omega interposon (Prentki and Krisch 1984) located upstream of the promoters and a hybrid β-glucanase gene of Bacillus. When controlled by the fic promoter, the kil gene led to a higher total production of β-glucanase and a higher protein secretion than when it was under control of the
bolA promoter. When the effect of different distances between the stationary-phase promoters and the kil gene was investigated, a shorter distance was generally found to result in a higher secretion. With a complex growth medium,
the kinetics of extracellular production of the enzyme depended on several operating variables, such as the salt concentration
(NaCl) and the oxygen supply, which were varied by changing the culture volume and the shaking speed. In defined media the
secretion of β-glucanase into the medium was increased significantly by the addition of glycerol as a carbon source and by
prolonged cultivation. The strain with the highest production and secretion yield of β-glucanase [E. coli JM109(pLF3)] was tested on the fermenter scale.
Received: 1 July 1996 / Received revision: 23 September 1996 / Accepted: 29 September 1996 相似文献
7.
P. E. Hessler P. E. Larsen A. I. Constantinou K. H. Schram J. M. Weber 《Applied microbiology and biotechnology》1997,47(4):398-404
A search for an abundant and economical source of isoflavones, particularly genistein, led to the discovery that the erythromycin-producing
organism Saccharopolyspora erythraea also produces this promising new cancer-prevention agent. Erythromycin fermentation is a large-scale, soybean-based process
used world-wide for the commercial production of this medically important antibiotic. Results from this study indicate that
genistin (the glucoside form of genistein), which is added to the fermentation in the soybean media, was converted to genistein
through the action of a β-glucosidase produced by the organism. Genistein was co-extracted with erythromycin from the fermentation
broth, then separated from erythromycin during the second step of the purification process for the production of erythromycin.
Received 10 September 1996 / Received revision: 22 November 1996 / Accepted: 7 December 1996 相似文献
8.
J. Rabenhorst 《Applied microbiology and biotechnology》1996,46(5-6):470-474
In our screening program for microorganisms that are able to metabolize eugenol, the main component of the essential oil
of the clove tree Syzigium aromaticum (sy. Eugenia cariophyllus), we found a new Pseudomonas sp. that produces several substituted methoxyphenols when eugenol is fed to the culture. A taxonomic characterization of this
new organism has been performed. Examples of the biotransformation products, produced in high amounts, were vanillic acid
with 3.25 g/l within 99 h, ferulic acid with 5.8 g/l within 75 h and coniferyl alcohol with 3.22 g/l within 47.5 h. By changing
the culture conditions the ratio of the different metabolites could be varied. Based on these results a scheme for the degradation
of eugenol by this strain has been established.
Received: 1 April 1996 / Received revision: 24 June 1996 / Accepted: 1 July 1996 相似文献
9.
Application of the Plackett-Burman experimental design to evaluate nutritional requirements for the production of Colletotrichum coccodes spores 总被引:1,自引:0,他引:1
X. Yu S. G. Hallett J. Sheppard A. K. Watson 《Applied microbiology and biotechnology》1997,47(3):301-305
Colletotrichum coccodes is being examined as a biological weed control agent for velvetleaf (Abutilon theophrasti). A modified Richard's solution containing V-8 juice has been used to produce C. coccodes spores for growth-chamber and field experiments. Although C. coccodes sporulates well in this medium, V-8 is not available as a bulk commodity and is too expensive for commercial production.
Eight substrates were evaluated as replacements for V-8 juice in modified Richard's solution. Soy protein and casamino acids
were equal to V-8 juice for sporulation of C. coccodes. The Plackett-Burman experimental design was used to test the relative importance of various components of a complex medium
based on soy protein on mycelium biomass production and sporulation of C. coccodes. A new medium composed of sucrose (20 g/l), soy protein (5 g/l), KNO3 (5 g/l), KH2PO4 (5 g/l), MgSO4 (2 g/l), CaCl2 (0.5 g/l), and CuSO4 (0.05 g/l) was selected as the base medium for further study in the development of a low-cost and effective medium for C. coccodes spore production.
Received: 29 July 1996 / Received revision: 21 October 1996 / Accepted: 10 November 1996 相似文献
10.
M. J. Taherzadeh G. Lidén L. Gustafsson C. Niklasson 《Applied microbiology and biotechnology》1996,46(2):176-182
Physiological effects of deficiency of pantothenate, a necessary precursor in the synthesis of coenzyme A, were studied using
the yeast strain Saccharomyces cerevisiae CBS 8066. Cells were grown on defined media in anaerobic batch cultures with glucose (50 g/l) as the carbon and energy source.
Batch cultures containing more than 60 μg/l pantothenate showed no significant differences with respect to growth rates and
product yields. However, with an initial pantothenate concentration of 30 μg/l, the average glucose consumption rate was 50%
lower than in rich medium and, at even lower concentrations of pantothenate, the culture did not consume all the glucose in
the medium. Furthermore, pantothenate deficiency caused the acetate and pyruvate yields to increase and the biomass yield
to decrease, compared to the yields in pantothenate-rich medium. The increased acetate formation could be counteracted by
initial addition of acetate to the medium, and thereby the glycerol yield could be decreased. An initial addition of acetate
of 1.6 g/l to pantothenate-deficient medium (30 μg/l) caused a 35% decrease in glycerol yield and a 6% increase in ethanol
yield. Furthermore, the time required for complete conversion of the glucose decreased by 40%. Acetate addition affected the
acetate and glycerol yields in a similar way in pantothenate-rich medium (1000 μg/l) also.
Received: 27 December 1995/Received revision: 3 May 1996/Accepted: 9 May 1996 相似文献
11.
Y. Shiba F. Fukui K. Ichikawa N. Serizawa H. Yoshikawa 《Applied microbiology and biotechnology》1998,50(1):34-41
In order to develop a production process for carboxypeptidase Y (CPY, yeast vacuolar protease) secreted by Saccharomyces cerevisiae KS58-2D, medium composition, culture conditions, and expression systems were investigated. We found that the addition of
histidine to thiamine-free medium, in which CPY production was almost negligible, raised the intracellular thiamine level,
resulting in the increase of CPY production. On the basis of the choice of an expression system that uses an inducible GAL10 promoter, reassessment of histidine concentration in the medium, and optimization of the pH level during cultivation (pH
6.5), active CPY was secreted in a quantity of over 400 mg/l, which was more than tenfold that higher than that previously
reported. The process developed could be easily scaled-up to industrial-scale fermentation.
Received: 16 January 1998 / Received revision: 16 February 1998 / Accepted: 27 February 1998 相似文献
12.
Regeneration of garlic callus as affected by clonal variation, plant growth regulators and culture conditions over time 总被引:3,自引:0,他引:3
A long-term regeneration system for garlic (Allium sativum L.) clones of diverse origin was developed. Callus was initiated on a modified Gamborg's B-5 medium supplemented with 4.5 μM 2,4-D and maintained on the same basal medium with 4.7 μM picloram+0.49 μM 2iP. Regeneration potential of callus after 5, 12 and 16 months on maintenance medium was measured using several plant growth
regulator treatments. The 1.4 μM picloram+13.3 μM BA treatment stimulated the highest rate of shoot production. Regeneration rate decreased as callus age increased, but healthy
plantlets from callus cultures up to 16-months-old were produced for all clones. Regeneration of long-term garlic callus cultures
could be useful for clonal propagation and transformation.
Received: 24 September 1998 / Revision received: 27 January 1999 / Accepted: 26 February 1999 相似文献
13.
The use of molasses as a substrate for ethanol production by the thermotolerant yeast Kluyveromyces marxianus var. marxianus was investigated at 45°C. A maximum ethanol concentration of 7.4% (v/v) was produced from unsupplemented molasses at a concentration
of 23% (v/v). The effect on ethanol production of increasing the sucrose concentration in 23% (v/v) molasses was determined.
Increased sucrose concentration had a similar detrimental effect on the final ethanol produced as the increase in molasses
concentration. This indicated that the effect may be due to increased osmotic activity as opposed to other components in the
molasses. The optimum concentration of the supplements nitrogen, magnesium, potassium and fatty acid for maximum ethanol production
rate was determined using the Nelder and Mead (Computer J 7:308–313, 1965) simplex optimisation method. The optimum concentrations
of the supplements were 0.576 g l-1 magnesium sulphate, 0.288 g l-1 potassium dihydrogen phosphate and 0.36% (v/v) linseed oil. Added nitrogen in the form of ammonium sulphate did not affect
the ethanol production rate.
Received: 29 January 1996/Received revision: 23 April 1996/Accepted: 29 April 1996 相似文献
14.
H. Drechsel M. Tschierske A. Thieken G. Jung H. Zähner G. Winkelmann 《Journal of industrial microbiology & biotechnology》1995,14(2):105-112
Summary Rhizoferrin is a novel carboxylate-type siderophore which has recently been isolated fromRhizopus microsporus and other fungi of the Mucorales (Zygomycetes). The present investigation shows that a variety of rhizoferrin analogs can be produced by directed fermentation. Thus both the diaminobutane backbone and the citric acid side chains of rhizoferrin have been substituted by diamine and citric acid analogs added to the culture medium. The new ligands as well as their iron complexes have been characterized by physicochemical methods. Conditions of precursor incorporation and implications for the biosynthesis of the new siderophores are discussed. 相似文献
15.
H. Sudo A. Yamada K. Kokatsu N. Nakamura T. Matsunaga 《Applied microbiology and biotechnology》1997,47(1):78-82
The marine photosynthetic bacterium Chromatium sp. successfully removed orthophosphate when grown phototrophically. The phosphate-uptake rate was almost constant at more
than 5.0 mg- PO4
3−/l in synthetic medium. Addition of seawater causes flocculation of this strain. The successful use of seawater as an inexpensive
source of magnesium could prove to be effective in the removal of photosynthetic bacterial cells from a medium. A semicontinuous
culture system was used for the removal of low concentrations of phosphate and the phosphate-uptake activity of Chromatium sp. was maintained under 0.1 day−1 dilution rate. This strain was also able to remove high concentrations of phosphate from domestic sewage.
Received 24 May 1996 / Received revision: 5 August 1996 / Accepted: 6 September 1996 相似文献
16.
Cell-linked and extracellular cholesterol oxidase activities from Rhodococcus erythropolis. Isolation and physiological characterization 总被引:1,自引:0,他引:1
M. Sojo R. Bru D. Lopez-Molina F. Garcia-Carmona J.-C. Argüelles 《Applied microbiology and biotechnology》1997,47(5):583-589
Rhodococcus erythropolis cells growing in a cholesterol-free glycerol-containing mineral medium displayed very low levels of a cell-wall-bound cholesterol
oxidase activity. Addition of cholesterol induced a marked increase in the synthesis of this enzyme, which reached a maximum
within 6 days and was subsequently followed by the appearance of extracellular cholesterol oxidase in the culture broth. Significant
levels of induction were only achieved when cholesterol emulsified with Tween 80. The presence of chloramphenicol at the time
of induction completely prevented the emergence of both enzymatic forms, suggesting the requirement of de novo protein synthesis.
Upon transfer of cholesterol-growing cultures to fresh medium lacking cholesterol, the extracellular cholesterol oxidase was
quickly erased, while the activity of the particulate enzyme decreased sharply. The electrophoretic pattern on native Western
blotting as well as on sodium dodecyl sulphate/polyacrylamide gels, together with kinetic data, strongly support the idea
that the particulate and extracellular cholesterol oxidases are two different forms of the same enzyme with an estimated molecular
mass of 55 kDa.
Received: 26 September 1996 / Received revision: 30 December 1996 / Accepted: 4 January 1997 相似文献
17.
Two coals of different rank, mined in Russia, were treated by an anaerobic methanogenic enrichment culture. The addition
of alkaline enclosing rock to the lower-rank coal increased the pH of the incubation medium and methane production above that
of the higher-rank coal with addition of its enclosing rock. This effect was accompanied by the leaching of cations from the
incubation medium. The coal was processed without a preliminary chemical treatment in a two-stage aerobic/anaerobic bioreactor
containing an anaerobic methanogenic granulated enrichment culture.
Received: 15 January 1998 / Received revision: 2 October 1998 / Accepted: 2 October 1998 相似文献
18.
Nutrient cost is an important aspect in the fermentation of biomass to ethanol. With a goal of developing a cost-effective
fermentation medium, several industrially available nutrient sources were evaluated for their effectiveness in the simultaneous
saccharification and fermentation of pretreated poplar with Saccharomyces cerevisiae D5A. These studies showed that a low-cost medium containing 0.3% corn steep liquor and 2.5 mM MgSO4 · 7H2O was similar in performance to a nutrient-rich medium. Besides its low cost, this alternative medium consists of components
that are available on a commercial scale, thereby making it industrially relevant.
Received: 14 August 1996 / Received revision: 7 January 1997 / Accepted: 24 January 1997 相似文献
19.
Johannes Meiwes Hans-Peter Fiedler Hans Zähner Silvia Konetschny-Rapp Günther Jung 《Applied microbiology and biotechnology》1990,32(5):505-510
Summary
Streptomyces olivaceus TÜ 2718 produces the siderophore desferrioxamine E. Production depends on l-lysine and iron concentrations in the medium. With optimized conditions the yield of desferrioxamine E could be increased to 12g/1 in feeding fermentations. Supplementation of the basic production medium with natural and synthetic precursors of desferrioxamine E led to the production of twelve new analogues of desferrioxamine E.Offprint requests to: H. P. Fiedler 相似文献
20.
P. J. M. Teunissen H. J. Swarts J. A. Field 《Applied microbiology and biotechnology》1997,47(6):695-700
Ligninolytic basidiomycetes were screened for their ability to produce the tetrachlorinated hydroquinone metabolites drosophilin
A (DA, tetrachloro-4-methoxyphenol) and drosophilin A methyl ether (DAME, tetrachloro-1,4-dimethoxybenzene). Five fungal strains
produced these metabolites in detectable amounts, including strains from Bjerkandera and Peniophora, which are genera not previously known for DA or DAME production. Phellinus fastuosus ATCC26.125 had the highest and most reliable production of DA and DAME in peptone medium, respectively 15–60 μM and 4–40 μM.
This fungus was used to study culture conditions that could increase DAME production. A fourfold increase in DAME production
was found after the addition of hydroquinone to growing cultures of P. fastuosus. Therefore, hydroquinone is postulated to be a possible biosynthetic precursor of DAME in the fungus. Antagonising P. fastuosus by adding filter-sterilised culture fluid of a competing fungus, Phlebia radiata, increased DAME production significantly by tenfold. This result suggests that DAME production is elicited by compounds present
in the culture fluid of P. radiata, indicating that DAME has an antibiotic function in P. fastuosus.
Received: 17 September 1996 / Received revision: 7 February 1997 / Accepted: 15 February 1997 相似文献