共查询到20条相似文献,搜索用时 31 毫秒
1.
Woo Jun Kim Woo Gi Lee Kalaimahan Theodore Ho Nam Chang 《Biotechnology and Bioprocess Engineering》2001,6(1):6-10
The production of chitosan from the mycelia ofAbsidia coerulea was studied to improve cell growth and chitosan productivity. Culture conditions were optimized in batch cultivation (pH
4.5 agitator speed of 250 rpm, and aeration rate of, 2 vvm) and the maximum chitosan concentration achieved was 2.3 g/L under
optimized conditions. Continuous culture was carried out successfully by the formation of new growth spots under optimized
conditions, with a chitosan productivity of 0.052 gL−1 h−1, which is the highest value to date, and was obtained at a dilution rate of 0.05 h−1. Cell chitosan concentrations reached about 14% in the steady state, which is similar to that achieved in batch culture.
This study shows that for the continuous culture ofAbsidia coerulea it is vital to control the medium composition. 相似文献
2.
Chung Eun Chang Seung-Cheol Kim Jae-Seong So Hyun Shik Yun 《Biotechnology and Bioprocess Engineering》2001,6(2):128-132
Bacterial vaginosis can be treated by restoring the normal vaginal flora using lactobacilli.Lactobacillus crispatus KLB46 that was isolated from the human vagina has a strong antimicrobial activity and was grown in a batch and in a continuous
fermentor. During batch cultivation, the maximum specific growth rate ofL. crispatus KLB 46 was 0.63 h−1 and the highest viable cell count (1.9×109 CFU/mL) was obtained at pH 5.5.L. crispatus KLB 46 did not grow well at either pH 3.5 or 7.5. During continuous cultivation, the highest viable cell count (1.53×109 CFU/mL) was obtained at a dilution rate of 0.32 h−1. However, the maximum productivity of viable cells was obtained at a dilution rate of 0.52 h−1, and was 7.33×1011 CFU L−1 h−1, that is approximately 5 times higher than that obtained from batch culture. 相似文献
3.
The continuous production of citric acid from dairy wastewater was investigated using calcium-alginate immobilizedAspergillus niger ATCC 9142. The citric acid productivity and yield were strongly affected by the culture conditions. The optimal pH, temperature,
and dilution rate were 3.0, 30°C, and 0.025 h−1, respectively. Under optimal culture conditions, the maximum productivity, concentration, and yield of citric acid produced
by the calcium-alginate immobilizedAspergillus niger were 160 mg L−1 h−1, 4.5 g/L, and 70.3% respectively. The culture was continuously perfored for 20 days without any apparent loss in citric acid
productivity. Conversely, under the same conditions with a batch shake-flask culture, the maximum productivity, citric acid
concentration, and yield were only 63.3 mg L−1 h−1, 4.7 g/L and 51.4%, respectively. Therefore, the results suggest that the bioreactor used in this study could be potentially
used for continuous citric acid production from dairy wastewater by applying calcium-alginate immobilizedAspergillus niger. 相似文献
4.
Extracellular human granulocyte-macrophage colony stimulating factor (hGM-CSF) expression was studied under the control of
the GAP promoter in recombinant Pichia pastoris in a series of continuous culture runs (dilution rates from 0.025 to 0.2 h−1). The inlet feed concentration was also varied and the steady state biomass concentration increased proportionally demonstrating
efficient substrate utilization and constancy of the biomass yield coefficient (Yx/s) for a given dilution rate. The specific product formation rate (qP) showed a strong correlation with dilution rates demonstrating growth associated product formation of hGM-CSF. The volumetric
product concentration achieved at the highest feed concentration (4×) and a dilution rate of 0.2 h−1 was 82 mg l−1 which was 5-fold higher compared to the continuous culture run with 1× feed concentration at the lowest dilution rate thus
translating to a 40 fold increase in the volumetric productivity. The specific product yield (YP/X) increased slightly from 2 to 2.5 mg g−1, with increasing dilution rates, while it remained fairly invariant, for all feed concentrations demonstrating negligible
product degradation or feed back inhibition. The robust nature of this expression system would make it easily amenable to
scale up for industrial production. 相似文献
5.
The regulation of benzene degradation by Ralstonia pickettii PKO1 in the presence of the alternative substrate succinate was investigated in batch and continuous culture. In batch culture,
R. pickettii PKO1 achieved a maximum specific growth rate with benzene of 0.18 h−1, while succinate allowed much faster growth (μmax = 0.5 h−1). Under carbon excess conditions succinate repressed benzene consumption resulting in diauxic growth whereas under carbon-limited
conditions in the chemostat both substrates were used simultaneously. Moreover, the effect of succinate on the adaptation
towards growth with benzene was investigated in carbon-limited continuous culture at a dilution rate of 0.1 h−1 by changing the inflowing carbon substrate from succinate to different mixtures of benzene and succinate. The adaptation
process towards utilisation of benzene was rather complex. Three to seven hours after the medium shift biomass production
from benzene started. Higher proportions of succinate in the mixture had a positive effect on both the onset of biomass production
and on the time required for induction of benzene utilisation. Strikingly, after the initial increase in biomass and benzene-catabolising
activities, the culture collapsed regularly and wash-out of biomass was observed. After a transient phase of low biomass concentrations
growth on benzene resumed so that finally rather stable and high biomass concentrations were reached. The decrease in biomass
and degradative activities cannot be explained so far, but the possibilities of either intoxication of the cells by benzene
itself, or of inhibition by degradation intermediates were ruled out. 相似文献
6.
Kamakshi Gupta P. K. Mishra Pradeep Srivastava 《Biotechnology and Bioprocess Engineering》2009,14(2):207-212
Lovastatin, a hypocholesterolemic agent, is a secondary metabolite produced by filamentous microorganism Aspergillus terreus in submerged batch cultivation. Lovastatin production by pellets and immobilized siran cells was investigated in an airlift
reactor. The process was carried out by submerged cultivation in continuous mode with the objective of increasing productivity
using pellet and siran supported growth of A terreus. The continuous mode of fermentation improves the rate of lovastatin production. The effect of dilution rate and aeration
rate were studied in continuous culture. The optimum dilution rate for pellet was 0.02 h−1 and for siran carrier was 0.025 h−1. Lovastatin productivity using immobilized siran carrier (0.0255 g/L/h) was found to be greater than pellets (0.022 g/L/h).
The productivity by both modes of fermentation was found higher than that of batch process which suggests that continuous
cultivation is a promising strategy for lovastatin production. 相似文献
7.
Effects of methanol on expression of an anticoagulant hirudin in recombinant Hansenula polymorpha 总被引:1,自引:0,他引:1
A series of batch, fed-batch, and continuous cultures was carried out to analyze the effects of methanol on the fermentation
characteristics of recombinant Hansenula polymorpha for the production of hirudin, an anticoagulant. Hirudin expression efficiencies were greatly influenced by the methanol
concentrations in continuous and fed-batch culture modes. At a steady state of continuous culture, an optimum methanol concentration
of 1.7 g l−1 was determined at a dilution rate of 0.18 h−1 with 1.8 mg l−1 h−1 hirudin productivity. Journal of Industrial Microbiology & Biotechnology (2001) 27, 58–61.
Received 21 September 2000/ Accepted in revised form 10 June 2001 相似文献
8.
Burja AM Radianingtyas H Windust A Barrow CJ 《Applied microbiology and biotechnology》2006,72(6):1161-1169
An isolation program targeting Thraustochytrids (marine fungoid protists) from 19 different Atlantic Canadian locations was performed. Sixty-eight isolates were screened for biomass, total fatty acid (TFA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) content. Analysis of fatty acid methyl ester results discerned four distinctive clusters based on fatty acid profiles, with biomass ranging from 0.1 to 2.3 g L−1, and lipid, EPA, and DHA contents ranging from 27.1 to 321.14, 2.97 to 21.25, and 5.18 to 83.63 mg g−1 biomass, respectively. ONC-T18, was subsequently chosen for further manipulations. Identified using 18S rRNA gene sequencing techniques as a Thraustochytrium sp., most closely related to Thraustochytrium striatum T91-6, ONC-T18 produced up to 28.0 g L−1 biomass, 81.7% TFA, 31.4% (w/w biomass) DHA, and 4.6 g L−1 DHA under optimal fermentation conditions. Furthermore, this strain was found to produce the carotenoids and xanthophylls astaxanthin, zeaxanthin, canthaxanthin, echinenone, and β-carotene. Given this strain’s impressive productivity when compared to commercial strains, such as Schizochytrium sp. SR21 (which has only 50% TFA), coupled with its ability to grow at economical nitrogen and very low salt concentrations (2 g L−1), ONC-T18 is seen as an ideal candidate for both scale-up and commercialization. 相似文献
9.
The potential use of spin filter device to retainPropionibacterium acidipropionici in the bioreactor under continuous mode of fermentation and improve propionic acid productivity, was examined. The yield
of propionic acid based on lactose concentration was 51% in batch and 54% in continuous (dilution rate=0.05 h−1) operation. The yield in continuous fermentation with cell retention using spin filter of 10 micron size (dilution rate=0.05
h−1) was even higher at 70% (w/w). The volumetric productivity under batch and continuous mode of operation were 0.312 g L−1 h−1 and 0.718 g L−1 h−1 respectively. Continuous fermentation with cell retention demonstrated even higher volumetric productivities at 0.98 g L−1 h−1 with out clogging problems It could be used for utilization of cheese whey to produce propionic acid at higher yield and
productivities. 相似文献
10.
Production of 1,3-Propanediol by Clostridium butyricum VPI 3266 in continuous cultures with high yield and productivity 总被引:2,自引:0,他引:2
González-Pajuelo M Andrade JC Vasconcelos I 《Journal of industrial microbiology & biotechnology》2005,32(9):391-396
The effects of dilution rate and substrate feed concentration on continuous glycerol fermentation by Clostridium butyricum VPI 3266, a natural 1,3-propanediol producer, were evaluated in this work. A high and constant 1,3-propanediol yield (around
0.65 mol/mol), close to the theoretical value, was obtained irrespective of substrate feed concentration or dilution rate.
Improvement of 1,3-propanediol volumetric productivity was achieved by increasing the dilution rate, at a fixed feed substrate
concentration of 30, 60 or 70 g l−1. Higher 1,3-propanediol final concentrations and volumetric productivities were also obtained when glycerol feed concentration
was increased from 30 to 60 g l−1, at D=0.05–0.3 h−1, and from 60–70 g l−1, at D=0.05 and 0.1 h−1·30 g l−1 of 1,3-propanediol and the highest reported value of productivity, 10.3 g l−1 h−1, was achieved at D=0.30 h−1 and 60 g l−1 of feed glycerol. A switch to an acetate/butyrate ratio higher than one was observed for 60 g l−1 of feed glycerol and a dilution rate higher than 0.10 h−1; moreover, at D=0.30 h−1 3-hydroxypropionaldehyde accumulation was observed for the first time in the fermentation broth of C. butyricum. 相似文献
11.
Shokrollahzadeh S Bonakdarpour B Vahabzadeh F Sanati M 《Journal of industrial microbiology & biotechnology》2007,34(1):17-25
The effect of phosphate (P
i
) concentration on the growth behavior of Saccharomyces cerevisiae strain CEN.PK113-5D in phosphate-limited batch and chemostat cultures was studied. The range of dilution rates used in the present study was 0.08–0.45 h−1. The batch growth of yeast cells followed Monod relationship, but growth of the cells in phosphate-limited chemostat showed change in growth kinetics with increasing dilution rates. The difference in growth kinetics of the yeast cells in phosphate-limited chemostat for dilution rates below and above approximately 0.2 h−1 has been discussed in terms of the batch growth kinetic data and the change in the metabolic activity of the yeast cells. Immunological detection of a C-terminally myc epitope-tagged Pho84 fusion protein indicated derepressive expression of the Pho84 high-affinity P
i
transporter in the entire range of dilution rates employed in this study. Phosphate transport activity mediated by Pho84 transporter was highest at very low dilution rates, i.e. 0.08–0.1 h−1, corresponding to conditions in which the amount of synthesized Pho84 was at its maximum. 相似文献
12.
Sirisansaneeyakul S Luangpipat T Vanichsriratana W Srinophakun T Chen HH Chisti Y 《Journal of industrial microbiology & biotechnology》2007,34(5):381-391
Production of lactic acid from glucose by immobilized cells of Lactococcus lactis IO-1 was investigated using cells that had been immobilized by either entrapment in beads of alginate or encapsulation in
microcapsules of alginate membrane. The fermentation process was optimized in shake flasks using the Taguchi method and then
further assessed in a production bioreactor. The bioreactor consisted of a packed bed of immobilized cells and its operation
involved recycling of the broth through the bed. Both batch and continuous modes of operation of the reactor were investigated.
Microencapsulation proved to be the better method of immobilization. For microencapsulated cells at immobilized cell concentration
of 5.3 g l−1, the optimal production medium had the following initial concentrations of nutrients (g l−1): glucose 45, yeast extract 10, beef extract 10, peptone 7.5 and calcium chloride 10 at an initial pH of 6.85. Under these
conditions, at 37 °C, the volumetric productivity of lactic acid in shake flasks was 1.8 g l−1 h−1. Use of a packed bed of encapsulated cells with recycle of the broth through the bed, increased the volumetric productivity
to 4.5 g l−1 h−1. The packed bed could be used in repeated batch runs to produce lactic acid. 相似文献
13.
Octavio Carvajal-Zarrabal Cirilo Nolasco-Hipólito Kopli B. Bujang Ayaaki Ishizaki 《Journal of industrial microbiology & biotechnology》2009,36(3):409-415
A membrane bioreactor for production of nisin Z was constructed using Lactococcus lactis IO-1 in continuous culture using hydrolyzed sago starch as carbon source. A strategy used to enhance the productivity of
nisin Z was to maintain the cells in a continuous growth at high cell concentration. This resulted in a volumetric productivity
of nisin Z, as 50,000 IU l−1 h−1 using a cell concentration of 15 g l−1, 30°C, pH 5.5 and a dilution rate of 1.24 h−1. Adding 10 g l−1 YE and 2 g l−1 polypeptone, other inducers were unnecessary to maintain production of nisin. The operating conditions of the reactor removed
nisin and lactate, thus minimizing their effects which allowed the maintenance of cells in continuous exponential growth phase
mode with high metabolic activity. 相似文献
14.
Co-production of biomass and metabolites by cell retention culture of <Emphasis Type="Italic">Leuconostoc citreum</Emphasis> 总被引:1,自引:0,他引:1
Cell retention culture of lactic acid bacterium Leuconostoc citreum was carried out in a fermentor equipped with an internal ceramic filtration system to co-produce biomass and metabolites.
The filtration system was composed of porous ceramic filter module with pore size of 0.1 μm and total surface area of 330 cm2. High cell density cultivation of L. citreum was achieved within the fermentor, while extracellular metabolites such as mannitol and d-lactic acid were produced through the filter with high productivities. In batch culture of L. citreum using a medium containing 50 g/L of glucose and 100 g/L of fructose, the maximum optical density (OD) monitored at 660 nm
was 13 with 65 g/L of mannitol and 38 g/L of lactic acid. In cell retention culture of L. citreum with dilution rate of 0.07 h−1, OD increased to 75, which was 6 times higher than that in batch culture. The concentrations of mannitol and lactic acid
increased to 85 and 45 g/L, respectively, and were maintained throughout the cultivation to 105 h. By increasing dilution
rate to 0.13 h−1, the productivities of mannitol and lactic acid increased to 8.5 and 4.2 g/L/h, respectively, which were 2.7 to 3 times higher
than those in batch culture, suggesting that cell retention culture using internal filtration system is highly effective for
co-production of useful cell biomass and various extracellular metabolites. 相似文献
15.
Kaarel Adamberg Petri-Jaan Lahtvee Kaspar Valgepea Kristo Abner Raivo Vilu 《Antonie van Leeuwenhoek》2009,95(3):219-226
Quasi steady state growth of Lactococcus
lactis IL 1403 was studied in glucose-limited A-stat cultivation experiments with acceleration rates (a) from 0.003 to 0.06 h−2 after initial stabilization of the cultures in chemostat at D = 0.2–0.3 h−1. It was shown that the high limit of quasi steady state growth rate depended on the acceleration rate used—at an acceleration
rate 0.003 h−2 the quasi steady state growth was observed until μ
crit = 0.59 h−1, which is also the μ
max value for the culture. Lower values of μ
crit were observed at higher acceleration rates. The steady state growth of bacteria stabilized at dilution rate 0.2 h−1 was immediately disrupted after initiating acceleration at the highest acceleration rate studied—0.06 h−2. Observation was made that differences [Δ(μ − D)] of the specific growth rates from pre-programmed dilution rates were the lowest using an acceleration rate of 0.003 h−2 (< 4% of preset changing growth rate). The adaptability of cells to follow preprogrammed growth rate was found to decrease
with increasing dilution rate—it was shown that lower acceleration rates should be applied at higher growth rates to maintain
the culture in the quasi steady state. The critical specific growth rate and the biomass yields based on glucose consumption
were higher if the medium contained S
0 = 5 g L−1 glucose instead of S
0 = 10 g L−1. It was assumed that this was due to the inhibitory effect of lactate accumulating at higher concentrations in the latter
cultures. Parallel A-stat experiments at the same acceleration and dilution rates showed good reproducibility—Δ(μ − D) was less than 5%, standard deviations of biomass yields per ATP produced (Y
ATP), and biomass yields per glucose consumed (Y
XS) were less than 15%. 相似文献
16.
The continuous fermentation of 1,3-propanediol from glycerol by Clostridium butyricum was subjected to cell recycling by filtration using hollow-fibre modules made from polysulphone. The performance of the culture
system was checked at a retention ratio (dilution rate/bleed rate) of 5, dilution rates between 0.2 h−1 and 1.0 h−1 and glycerol input concentrations of 32 g l−1 and 56 g l−1. The near-to-optimum propanediol concentration of 26.5 g l−1 (for 56 g l−1 glycerol) was maintained up to a dilution rate of 0.5 h−1 and then decreased while the propanediol productivity was highest at 0.7 h−1. The productivity could be increased by a factor of four in comparison to the continuous culture without cell recycling.
By application of the model of Zeng and Deckwer [(1995) Biotechnol Prog 11: 71–79] for cultures under substrate excess, it
was shown that the limitations resulted exclusively from product inhibition and detrimental influences from the cell recycling
system, such as shear stress, were not involved.
Received: 20 October 1997 / Received revision: 12 December 1997 / Accepted: 14 December 1997 相似文献
17.
Quillaguamán J Doan-Van T Guzmán H Guzmán D Martín J Everest A Hatti-Kaul R 《Applied microbiology and biotechnology》2008,78(2):227-232
High poly(3-hydroxybutyrate) (PHB) content and volumetric productivity were achieved by fed-batch culture of Halomonas boliviensis using a defined medium. Initial shake flask cultivations in a minimal medium revealed that the growth of H. boliviensis was supported only when the medium was supplemented with aspartic acid, glycine, or glutamine. Addition of 0.1% (w/v) glutamine in the medium resulted in the highest cell dry weight (CDW; 3.9 g l−1). Glutamine was replaced by the less expensive monosodium glutamate (MSG) in the medium without any notable change in the
final cell density. Effect of initial concentrations of NH4Cl and K2HPO4 on cell growth and PHB accumulation by H. boliviensis was then analyzed using a fed-batch fermentation system. The best conditions for PHB production by H. boliviensis were attained using 0.4% (w/v) NH4Cl and 0.22% (w/v) K2HPO4 and adding MSG intermittently to the fermentor. Poly(3-hydroxybutyrate) content and CDW reached 90 wt.% and 23 g l−1, respectively, after 18 h of cultivation. In order to increase CDW and PHB content, MSG, NH4Cl, and K2HPO4 were initially fed to the fermentor to maintain their concentrations at 2%, 0.4%, and 0.22% (w/v), respectively, and subsequently their feed was suppressed. This resulted in a CDW of 44 g l−1, PHB content of 81 wt.%, and PHB volumetric productivity of 1.1 g l−1 h−1. 相似文献
18.
A two-stage continuous culture of Escherichia coli in combination with a bacteriophage λ system was performed in order to overcome the intrinsic plasmid instability that is
frequently observed in recombinant fermentation. A phage λ vector with a Q
− mutation was used to enhance the expression of the λ system. The optimal values of the important operational variables such
as the substrate concentration, the dilution rate, and the mean residence time on the expression of the cloned gene were determined
in both batch and continuous cultures. For all culturing modes, the full induction of the cloned gene was observed 4 h after
the temperature shift. In the two stage continuous culture, the overproduction reached their maxima at D=0.25 h−1 with 1.5 S
0 of the medium supply. The maximum productivity of the total β-galactosidase was 16.3×106 U l−1 h−1, which was approximately seven times higher than that in the single-copy lysogenic stage. The recombinant cells were stable
in the lysogenic state for more than 260 h, while they were stable for 40 h in the lytic state. The instability that developed
rapidly in the second tank is believed to be due to the accumulation of lysis proteins as a result of vector leakage during
the operation. 相似文献
19.
Hoi-Ping Shi Chi-Mei Lee Wei-Hsien Ma 《World journal of microbiology & biotechnology》2007,23(5):625-632
Polyhydroxyalkanoates (PHAs), intracellular carbon and energy reserve compounds in many bacteria, have been used extensively
in biodegradable plastics. PHA formation is influenced by nutrient limitations and growth conditions. To characterize the
PHA accumulation in a new denitrifying phosphorus-removing bacterium Brachymonas sp. P12, batch experiments were conducted in which the electron acceptor (oxygen or nitrate) was varied and different concentrations
of carbon (acetate), nitrogen (NH4Cl), and phosphorus (KH2PO4) were used. Polyhydroxybutyrate (PHB) was the dominant product during PHA formation when acetate was the sole carbon source.
The PHB content of aerobically growing cells increased from 431 to 636 mg PHB g−1 biomass, but the PHB concentration of an anoxic culture decreased (−218 mg PHB g−1 biomass), when PHB was utilized simultaneously with acetate as an electron donor for anoxic denitrification. The specific
PHB production rate of the carbon-limited batch, 158.2 mg PHB g−1 biomass h−1, was much greater than that of batches with normal or excess carbon. The effects of phosphorus and nitrogen concentrations
on PHB accumulation were clearly less than the effect of carbon concentration. According to the correlation between the specific
PHB production rate and the specific cell growth rate, PHB accumulation by Brachymonas sp. P12 is enhanced by nutrient limitation, is growth-associated, and provides additional energy for the biosynthesis of
non-PHB cell constituents to increase the cell growth rate beyond the usual level. 相似文献
20.
Ö. Şimşek N. Akkoç A. H. Çon F. Özçelik P. E. J. Saris Mustafa Akçelik 《Journal of industrial microbiology & biotechnology》2009,36(6):863-871
Nisin production in continuous cultures of bioengineered Lactococcus lactis strains that incorporate additional immunity and regulation genes was studied. Highest nisin activities were observed at
0.2 h–1 dilution rate and 12.5 g l–1 fructose concentration for all strains. Recombinant strains were able to produce greater amounts of nisin at dilution rates
below 0.3 h−1 compared to the control strain. However, this significant difference disappeared at dilution rates of 0.4 and 0.5 h–1. For the strains LL27, LAC338, LAC339, and LAC340, optimum conditions for nisin production were determined to be at 0.29,
0.26, 0.27, and 0.27 h–1 dilution rates and 11.95, 12.01, 11.63, and 12.50 g l–1 fructose concentrations, respectively. The highest nisin productivity, 496 IU ml–1 h–1, was achieved with LAC339. The results of this study suggest that low dilution rates stabilize the high specific nisin productivity
of the bioengineered strains in continuous fermentation. Moreover, response surface methodology analysis showed that regulation
genes yielded high nisin productivity at wide ranges of dilution rates and fructose concentrations. 相似文献