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1.
The physiological response of erythromycin fermentation scale-up from 50 L to 132 m3 scale was investigated. A relatively high oxygen uptake rate (OUR) in early phase of fermentation was beneficial for erythromycin
biosynthesis. Correspondingly, the maximal consistency coefficient (K) reflecting non-Newtonian fluid characteristics in 50 L and 132 m3 fermenter also appeared in same phase. Fluid dynamics in different scale bioreactor was further investigated by real-time
computational fluid dynamics modeling. The results of simulation showed that the impeller combination in 50 L fermenter could
provide more modest flow field environment compared with that in 132 m3 fermenter. The decrease of oxygen transfer rate (OTR) in 132 m3 fermenter was the main cause for impairing cell physiological metabolism and erythromycin biosynthesis. These results were
helpful for understanding the relationship between hydrodynamic environment and physiological response of cells in bioreactor
during the scale-up of fermentation process. 相似文献
2.
The Zymomonas mobilis 113 S strain was cultivated in a bioreactor with a working volume of 1.4 l at different stirring regimes in a 15% initial sucrose medium. The levan obtained in the fermentation process was analyzed by gel filtration. Because the sucrose/biomass ratio in the fermentation broth decreased to below 300 g/g, the insufficient concentration of sucrose might have decreased the concentration of levan. Besides the growth characteristics of the population, the mixing intensity and flow structure were also found to influence the molecular mass of levan. At 600 rpm, the microorganisms produced levan with a molecular mass lower than at 300 rpm. The stirring of a fermentation broth with levan without cells at 300 rpm and 900 rpm showed changes in the molecular mass approximately at 20 kD and 5 kD. The size of eddies in the fermenter was supposed to determine the size of a levan molecule. Because the size of the eddy may be compared with that of a levan molecule, it explains the decline in the molecular mass of levan. 相似文献
3.
The influence of two mixing systems on the principal parameters of mycelial fermentations of Aspergillus niger, Fusicoccum amygdali Del. and Fusarium moniliforme Sheld. as well as their metabolite citric acid, fusicoccin and gibberellic acid production was analyzed from the viewpoint of flow energy distribution in a bioreactor. The growth and metabolite synthesis during fermentation was compared under different mixing conditions in the fermenter FU-8 with a turbine mixing system (TMS) and a counterflow mixing system (CMS). It was found that the growth, productivity and respiration characteristics as well as the morphology of these cultures varied dependent on the mixing system and agitation regime used. The counterflow mixing system was more favourable for large agglomerates (F. amygdali) or soft pellets (A. niger) forming fungi, while the turbine mixing system was more effective for F. moniliforme growing in the form of small clumps and freely dispersed hyphae. Flow characteristics under different mixing conditions were analyzed in a model fermenter. The kinetic energy of flow fluctuations was measured in gassed and ungassed water and different fermentation broth systems by using a Stirring Intensity Measuring Device (SIMD-F1). The difference of the energy values at different points was better expressed in the fermenter with a turbine mixing system in comparison with that having a counterflow mixing system. High viscous F. amygdali and A. niger broth provided higher energy values compared to water and low viscous F. moniliforme broth. It was observed that the intensity of growth and the intensity of the synthesis decreased at very high energy values, which was obviously connected to the influence of the irreversible shear stress on the mycelial morphology. 相似文献
4.
Modeling of microbial growth using nonmiscible substrate is studied when kinetics of substrate dissolution is rate limiting. When the substrate concentration is low, the growth rate is described by an analytical relation that can be identified as a Contois relationship. If the substrate concentration is greater than a critical value Scrit, the potentially useful hydrocarbon S* concentration is described by S* = Scrit/(1 + Scrit/S). A relationship was found between Scrit and the biomass concentration X. When X increased, Scrit decreased. The cell growth rate is related to a relation μ = μm[A(X/Scrit)(1 + Scrit/S) + 1]?1. This model describes the evolution of the growth rate when exponential or linear growth occurs, which is related to physico-chemical properties and hydrodynamic fermentation conditions. Experimental data to support the model are presented. 相似文献
5.
Aims: To study the optimization of submerged culture conditions for exopolysaccharide (EPS) production by Armillaria mellea in shake‐flask cultures and also to evaluate the performance of an optimized culture medium in a 5‐l stirred tank fermenter. Methods and Results: Shake flask cultures for EPS optimal nutritional production contained having the following composition (in g l?1): glucose 40, yeast extract 3, KH2PO4 4 and MgSO4 2 at an optimal temperature of 22°C and an initial of pH 4·0. The optimal culture medium was then cultivated in a 5‐l stirred tank fermenter at 1 vvm (volume of aeration per volume of bioreactor per min) aeration rate, 150 rev min?1 agitation speed, controlled pH 4·0 and 22°C. In the optimal culture medium, the maximum EPS production in a 5‐l stirred tank fermenter was 588 mg l?1, c. twice as great as that in the basal medium. The maximum productivity for EPS (Qp) and product yield (YP/S) were 42·02 mg l?1 d?1 and 26·89 mg g?1, respectively. Conclusions: The optimal culture conditions we proposed in this study enhanced the EPS production of A. mellea from submerged cultures. Significance and Impact of the Study: The optimal culturing conditions we have found will be a suitable starting point for a scale‐up of the fermentation process, helping to develop the production of related medicines and health foods from A. mellea. 相似文献
6.
Ying-ping Huang Ali Haris Malik Zhi-ying Tu David Johnson Wei-Ming Li Xi Yuan 《Zeitschrift fur angewandte Ichthyologie》2020,36(6):811-816
The swimming performance of juvenile rock carp (Procypris rabaudi, Tchang) subjected to repeated fatigue exercise was studied using a flume-type respirometer at 20°C. The critical swimming speed (Ucrit) and oxygen consumption rate (MO2) of juvenile rock carp were measured during two successive stepped velocity tests, following a 60 min rest interval. Ucrit of rock carp was giving a recovery ratio (Rr) of 92.64%, and exertion exercise decreases Ucrit. When MO2 was plotted as a linear function of U, the slope for trial 1 was 1.06 and 1.50 for trial 2, indicating a decreasing in swimming efficiency. The maximum metabolic rate (MMR) increased from 17.06 ± 1.14 mmol O2/(kg·hr) to 19.14 ± 1.23 mmol O2/(kg·hr), and the exercise post oxygen consumption rate (EPOC) increased from 9.00 to 9.65 mmol O2/kg. Repeated fatiguing exercise increased both the aerobic and anaerobic cost of reaching Ucrit, but anaerobic metabolism accounted for a larger proportion in the trial 2. The data investigation on the swimming performance and the physiological response to fatigue provide important design criteria for fishways. 相似文献
7.
The pigment composition of two species of green-colored BChl c-containing green sulfur bacteria (Chlorobium limicola and C. chlorovibrioides) and two species of brown-colored BChl e-containing ones (C. phaeobacteroides and C. phaeovibrioides) incubated at different light intensities have been studied. All species responded to the reduction of light intensity from 50 to 1 Einstein(E) m–2 s–1 by an increase in the specific content of light harvesting pigments, bacteriochlorophylls and carotenoids. At critical light intensities (0.5 to 0.1 E m–2 s–1) only brown-colored chlorobia were able to grow, though at low specific rates (0.002 days–1 mg prot–1). High variations in the relative content of farnesyl-bacteriochlorophyll homologues were found, in particular BChl e
1 and BChl e
4, which were tentatively identified as [M, E] and [I, E] BChlF
e, respectively. The former was almost completely lost upon reduction of light intensity from 50 to 0.1 E m–2 s–1, whereas the latter increased from 7.2 to 38.4% and from 13.6 to 42.0% in C. phaeobacteroides and C. phaeovibrioides, respectively. This increase in the content of highly alkylated pigment molecules inside the chlorosomes of brown species is interpreted as a physiological mechanism to improve the efficiency of energy transfer towards the reaction center. This study provides some clues for understanding the physiological basis of the adaptation of brown species to extremely low light intensities.Abbreviations BChl
bacteriochlorophyll
- [M, E] BChlF
e
8-methyl, 12-ethyl BChl e, esterified with farnesol (F). Analogously: I - isobutyl
- Pr
propyl
- Car
carotenoids
- Chlb
chlorobactene
- HPLC
high performance liquid chromatography
- Isr
isorenieratene
- LHP
light harvesting pigments
- PDA
photodiode array detector
- RC
reaction center
- RCH
relative content of homologues 相似文献
8.
Karl J. Niklas 《American journal of botany》1994,81(3):345-351
Regression curves for the relation between the critical buckling height Hcrit, and the diameter D of columnar support members composed exclusively of different tissues were established based on Greenhill's formula and previously reported mean values for the density-specific stiffness and density-specific strength of parenchyma, primary xylem, sclerenchyma, and wood. These regression curves were used to determine the extent to which the actual heights H of 249 plant species approach or transgress the Hcrit for stems relying principally upon different tissue-types for stiffness. Based on empirically determined H and estimated Hcrit, the safety-factor Hcrit/H (computed on the basis of E/p) against elastic instability resulting from self-loading imposed on stems was determined for dicot and gymnosperm tree species (N = 56), mosses (N = 40), pteridophytes (N = 16), dicot herbs (N = 120), and palms (N = 17). With the exception of tree species, Hcrit/H was size-dependent, decreasing with increasing D. This was a consequence of the scaling exponents (i.e., the slopes of the regression curves) for tree Hcrit, vs. D and H vs. D which were nearly identical, whereas the scaling exponents for H vs. D for “nonwoody” species were in excess of those for Hcrit, vs. D. With the exception of a few very tall specimens of palm species, however, the majority of nonwoody and woody species did not exceed their estimated Hcrit. The upper size-range obtained by the procession of taller plant grades and clades was bounded by the regression curves of Hcrit, vs. D established for progressively stiffer plant tissues: parenchyma Å primary xylem Å sclerenchyma Å wood. This appears to be a consequence of the incorporation of progressively stiffer tissues within the stems of taller nonwoody species and the adjustment in the girth of stems, which developmentally occurs for trees. 相似文献
9.
Maris Rikmanis Andrejs Berzinš Uldis Viesturs 《Central European Journal of Biology》2007,2(4):481-501
The present review describes the influence of different types of mixing systems under excess turbulence conditions on microorganisms.
Turbohypobiosis phenomena were described by applying a method for measurement of the kinetic energy of flow fluctuations based
on the piezoeffect. It can be assumed that the shear stress effect (the state of turbohypobiosis) plays a role mainly when
alternative mechanisms in cells cannot ensure a normal physiological state under stress conditions. Practically any system
(inner construction of a bioreactor, culture and cultivation conditions, including mixing) requires its own optimisation to
achieve the final goal, namely, the maximum product and/or biomass yields from substrate (Y
P/S
or/and Y
X/S
), respectively. Data on the biotechnological performance of cultivation as well as power input, kinetic energy (e) of flow fluctuations, air consumption rate, rotational speed, tip speed, etc. do not correlate directly if the mixing systems (impellers-baffles) are dissimilar. Even the widely used specific power consumption
cannot be relied upon for scaling up the cultivation performance using dissimilar mixing systems. A biochemical explanation
for substrate and product transport via cell walls, carbon pathways, energy generation and utilisation, etc. furnishes insight into cellular interactions with turbulence of different origin for different types of microorganisms (single
cells, mycelia forming cells, etc.). 相似文献
10.
M Vitolo M A Duranti M B Pellegrim 《Journal of industrial microbiology & biotechnology》1995,15(2):75-79
S. cerevisiae was grown in a blackstrap molasses containing medium in batch and fed-batch cultures. The following parameters were varied: pH (from 4.0 to 6.5), dissolved oxygen (DO) (from 0 to 5.0 mg O2L–1) and sucrose feeding rate. When glucose concentration (S) was higher than 0.5 g L–1 a reduction in the specific invertase activity of intact cells (v) and an oscillatory behavior of v values during fermentation were observed. Both the invertase reduction and the oscillatory behavior of v values could be related to the glucose inhibitory effect on invertase biosynthesis. The best culture conditions for attainingS. cerevisiae cells suitable for invertase production were: temperature=30°C; pH=5.0; DO=3.3 mg O2L–1; (S)=0.5 g L–1 and sucrose added into the fermenter according to the equations: (V–Vo)=t2/16 or (V–Vo)=(Vf–Vo)·(e0.6t–1)/10.This work was supported by FAPESP 相似文献
11.
Fluid dynamics of anaerobic fermentation 总被引:2,自引:0,他引:2
In beer fermentation, yeast cells are kept in suspension, despite their higher density, by natural agitation created by ascending CO2 bubbles. Yeast cells are unable to nucleate bubbles but instead release CO2 in a soluble form in such a way that the medium tends to become supersaturated. A higher concentration of yeast cells and the presence of solid particles cause the formation of bubbles at the bottom of the fermenter and practically only there. The rising bubbles grow and accelerate by sweeping the CO2 formed throughout the fermenter by the suspended yeast cells, thereby creating a fluid regime. A mathematical expression relating the bubble agitation power to the fermentation parameters was obtained and used to design more efficient fermenter shapes. 相似文献
12.
Summary The scale-up of a whey fermentation byKluyveromyces fragilis was carried out in order to reproduce on a larger scale (100-l fermenter) the results obtained on a smaller scale (15-l fermenter).Using a standard procedure for inoculum development and medium pasteurization, the effects of mixing and lactose concentration on yeast growth, lactose consumption, COD reduction and dissolved oxygen have been studied.The most successful operation for this fermentation was found to be associated with high stirring rates and low lactose concentrations, since the process was controlled by both oxygen and lactose concentrations. 相似文献
13.
A O Ejiofor Y Chisti M Moo-Young 《Journal of industrial microbiology & biotechnology》1996,16(2):102-109
A fermentation medium based on millet (Pennisetum typhoides) flour hydrolysate and a four-phase feeding strategy for fed-batch production of baker's yeast,Saccharomyces cerevisiae, are presented. Millet flour was prepared by dry-milling and sieving of whole grain. A 25% (w/v) flour mash was liquefied with a thermostable 1,4--d-glucanohydrolase (EC 3.2.1.1) in the presence of 100 ppm Ca2+, at 80°C, pH 6.1–6.3, for 1 h. The liquefied mash was saccharified with 1,4--d-glucan glucohydrolase (EC 3.2.1.3) at 55°C, pH 5.5, for 2 h. An average of 75% of the flour was hydrolysed and about 82% of the hydrolysate was glucose. The feeding profile, which was based on a model with desired specific growth rate range of 0.18–0.23 h–1, biomass yield coefficient of 0.5 g g–1 and feed substrate concentration of 200 g L–1, was implemented manually using the millet flour hydrolysate in test experiments and glucose feed in control experiments. The fermentation off-gas was analyzed on-line by mass spectrometry for the calculation of carbon dioxide production rate, oxygen up-take rate and the respiratory quotient. Off-line determination of biomass, ethanol and glucose were done, respectively, by dry weight, gas chromatography and spectrophotometry. Cell mass concentrations of 49.9–51.9 g L–1 were achieved in all experiments within 27 h of which the last 15 h were in the fedbatch mode. The average biomass yields for the millet flour and glucose media were 0.48 and 0.49 g g–1, respectively. No significant differences were observed between the dough-leavening activities of the products of the test and the control media and a commercial preparation of instant active dry yeast. Millet flour hydrolysate was established to be a satisfactory low cost replacement for glucose in the production of baking quality yeast.Nomenclature
C
ox
Dissolved oxygen concentration (mg L–1)
-
CPR
Carbon dioxide production rate (mmol h–1)
-
C
s0
Glucose concentration in the feed (g L–1)
-
C
s
Substrate concentration in the fermenter (g L–1)
-
C
s.crit
Critical substrate concentration (g L–1)
-
E
Ethanol concentration (g L–1)
-
F
s
Substrate flow rate (g h–1)
-
i
Sample number (–)
-
K
e
Constant in Equation 6 (g L–1)
-
K
o
Constant in Equation 7 (mg L–1)
-
K
s
Constant in Equation 5 (g L–1)
-
m
Specific maintenance term (h–1)
-
OUR
Oxygen up-take rate (mmol h–1)
-
q
ox
Specific oxygen up-take rate (h–1)
-
q
ox.max
Maximum specific oxygen up-take rate (h–1)
-
q
p
Specific product formation rate (h–1)
-
q
s
Specific substrate up-take rate (g g–1 h–1)
-
q
s.max
Maximum specific substrate up-take rate (g g–1 h–1)
-
RQ
Respiratory quotient (–)
-
S
Total substrate in the fermenter at timet (g)
-
S
0
Substrate mass fraction in the feed (g g–1)
-
t
Fermentation time (h)
-
V
Instantaneous volume of the broth in the fermenter (L)
-
V
0
Starting volume in the fermenter (L)
-
V
si
Volume of samplei (L)
-
x
Biomass concentration in the fermenter (g L–1)
-
X
0
Total amount of initial biomass (g)
-
X
t
Total amount of biomass at timet (g)
-
Y
p/s
Product yield coefficient on substrate (–)
-
Y
x/e
Biomass yield coefficient on ethanol (–)
-
Y
x/s
Biomass yield coefficient on substrate (–)
Greek letters
Moles of carbon per mole of yeast (–)
-
Moles of hydrogen atom per mole of yeast (–)
-
Moles of oxygen atom per mole of yeast (–)
-
Moles of nitrogen atom per mole of yeast (–)
-
Specific growth rate (h–1)
- crit
Critical specific growth rate (h–1)
-
E
Specific ethanol up-take rate (h–1)
- max.E
Maximum specific ethanol up-take rate (h–1) 相似文献
14.
K. J. Rodnick A. K. Gamperl K. R. Lizars M. T. Bennett R. N. Rausch E. R. Keeley 《Journal of fish biology》2004,64(2):310-335
Streamside measurements of critical thermal maxima (Tcrit), swimming performance (Ucrit), and routine (Rr) and maximum (Rmax) metabolic rates were performed on three populations of genetically distinct redband trout Oncorhynchus mykiss in the high‐desert region of south‐eastern Oregon. The Tcrit values (29·4 ± 0·1° C) for small (40–140 g) redband trout from the three streams, and large (400–1400 g) redband trout at Bridge Creek were not different, and were comparable to published values for other salmonids. At high water temperatures (24–28° C), large fish incurred higher metabolic costs and were more thermally sensitive than small fish. Ucrit(3·6 ± 0·1 LF s?1), Rr(200 ± 13 mg O2 kg?0·830 h?1) and metabolic power (533 ± 22 mg O2 kg?0·882 h?1) were not significantly different between populations of small redband trout at 24° C. Rmax and metabolic power, however, were higher than previous measurements for rainbow trout at these temperatures. Fish from Bridge Creek had a 30% lower minimum total cost of transport (Cmin), exhibited a lower refusal rate, and had smaller hearts than fish at 12‐mile or Rock Creeks. In contrast, no differences in Ucrit or metabolism were observed between the two size classes of redband trout, although Cmin was significantly lower for large fish at all swimming speeds. Biochemical analyses revealed that fish from 12‐mile Creek, which had the highest refusal rate (36%), were moderately hyperkalemic and had substantially lower circulating levels of free fatty acids, triglycerides and albumin. Aerobic and anaerobic enzyme activities in axial white muscle, however, were not different between populations, and morphological features were similar. Results of this study: 1) suggest that the physiological mechanisms that determine Tcrit in salmonids are highly conserved; 2) show that adult (large) redband trout are more susceptible to the negative affects of elevated temperatures than small redband trout; 3) demonstrate that swimming efficiency can vary considerably between redband trout populations; 4) suggest that metabolic energy stores correlate positively with swimming behaviour of redband trout at high water temperatures; 5) question the use of Tcrit for assessing physiological function and defining thermal habitat requirements of stream‐dwelling salmonids like the redband trout. 相似文献
15.
Relationships between metabolic rate, muscle electromyograms and swim performance of adult chinook salmon 总被引:2,自引:0,他引:2
D. R. Geist† R. S. Brown V. I. Cullinan‡ M. G. Mesa§ S. P. VanderKooi§ C. A. McKinstry¶ 《Journal of fish biology》2003,63(4):970-989
Oxygen consumption rates of adult spring chinook salmon Oncorhynchus tshawytscha increased with swim speed and, depending on temperature and fish mass, ranged from 609 mg O2 h?1 at 30 cm s?1 (c. 0·5 BL s?1) to 3347 mg O2 h?1 at 170 cm s?1 (c. 2·3 BL s?1). Corrected for fish mass, these values ranged from 122 to 670 mg O2 kg?1 h?1, and were similar to other Oncorhynchus species. At all temperatures (8, 12·5 and 17° C), maximum oxygen consumption values levelled off and slightly declined with increasing swim speed >170 cm s?1, and a third‐order polynomial regression model fitted the data best. The upper critical swim speed (Ucrit) of fish tested at two laboratories averaged 155 cm s?1 (2·1 BL s?1), but Ucrit of fish tested at the Pacific Northwest National Laboratory were significantly higher (mean 165 cm s?1) than those from fish tested at the Columbia River Research Laboratory (mean 140 cm s?1). Swim trials using fish that had electromyogram (EMG) transmitters implanted in them suggested that at a swim speed of c. 135 cm s?1, red muscle EMG pulse rates slowed and white muscle EMG pulse rates increased. Although there was significant variation between individual fish, this swim speed was c. 80% of the Ucrit for the fish used in the EMG trials (mean Ucrit 168·2 cm s?1). Bioenergetic modelling of the upstream migration of adult chinook salmon should consider incorporating an anaerobic fraction of the energy budget when swim speeds are ≥80% of the Ucrit. 相似文献
16.
X. He S. Lu M. Liao X. Zhu M. Zhang S. Li X. You J. Chen 《Journal of fish biology》2013,82(3):1047-1056
Changes in the critical swimming speed (Ucrit, cm s?1) with ontogeny of 2·5–12·5 month‐old juvenile anadromous Chinese sturgeon Acipenser sinesis were measured in a modified Blazka‐type swimming tunnel. The absolute Ucrit increased with length, mass and age; the relative U′crit (body lengths, s?1), however, decreased. Juvenile A. sinesis did not display a parr–smolt transformation at the length or age threshold to tolerate full‐strength seawater. 相似文献
17.
Nitrogen concentration of cauliflower organs as determined by organ size,N supply,and radiation environment 总被引:1,自引:0,他引:1
Data from field experiments carried out in three consecutive years under contrasting N supply and radiation environment altered by artificial shading were used to identify (a) the relationship between N concentration and organ size under conditions of unrestricted N supply and (b) critical levels of soil nitrate (Nmincrit), where nitrogen concentration of cauliflower organs begin to decline because of N limitations. The decline of N concentrations in cauliflower was analysed at different levels of morphological aggregation, i.e., the whole shoot level, the organ level (leaves, stem, and curd), and within different leaf groups within the canopy. Nmincrit values (0–60 cm soil depth) for total nitrogen concentration of cauliflower organs leaves, stem and curd were estimated at 85, 93 and 28 kg N ha–1, respectively. Within the canopy, Nmincrit values for total N of leaves increased from the top to the bottom from 44 to 188 kg N ha–1. Nmincrit values for protein N in leaves from different layers of the canopy were much lower at around 30 kg N ha–1, without a gradient within the canopy. It is discussed that these differences in Nmincrit values are most likely a consequence of N redistribution associated with nitrogen deficiency. The decline of average shoot nitrogen concentrations, [Nm] (%N DM), with shoot dry matter, W
sh, (t ha–1) under conditions of optimal N supply was [Nm]= 4.84 (±0.071) W
sh
–0.089(± 0.011), r
2=0.67 (±S.E.). The reduction of radiation intensity by artificial shading (60% of control) had no significant influence on total nitrogen concentrations of leaves and only a small influence on protein nitrogen concentrations in lower layers of the canopy. The leaf nitrate nitrogen fraction of nitrogen, f
nitr (–), within the canopy decreased linearly with increased average incident irradiance in different canopy layers (I
av, W PAR m–2) (f
Nitr. = 0.2456(±0.0188) – 0.0023(±0.0004)I
av, r
2 = 0.67. 相似文献
18.
The influence of basic physiological factors on the quality of inocula and L(+)-lactic acid production by Rhizopus arrhizus CCM 81 09 were studied. The most effective preparation of the spores (5 × 107 spores/ml) and subsequent good lactate production was achieved on the agar medium with soil extract and malt agar. The optimum initial amount of active spores for inoculation was 103–104 spores/ml. The preparation of inoculum required intensive stirring with lower aeration and pH maintained in the range from 4.8 to 6.0 by the addition of CaCO3. The maximum yield of lactic acid production was achieved by using 5% (v/v) of 24-h-old inoculum. The intensity of lactic acid production in the inoculum was proportional to its production in the subsequent steps of fermentation and can be used as a fast control of the physiological state of the producers. 相似文献
19.
The dissolved oxygen tension of 20% of air saturation, pH-shift from 4.0 to 5.5 on day 3, and a moderate shear stress (calculated
as an impeller tip speed,
V\texttip = 0. 9 2 6- 2. 1 6 1 \textm/\texts V_{\text{tip}} = 0. 9 2 6- 2. 1 6 1 \, {\text{m}}/{\text{s}} ) were identified to be the key factors in scaling-up the mated fermentation of Blakeslea trispora NRRL 2895 (+) and 2896 (−) for lycopene production from a shake flask to a stirred-tank fermenter. The maximal lycopene production
of 183.3 mg/L was obtained in 7.5-L stirred-tank fermenter, and then the mated fermentation process was successfully step-wise
scaled-up from 7.5- to 200-L stirred-tank fermenter. The comparability of the fermentation process was well controlled and
the lycopene production was maintained during the process scale-up. Furthermore, with the integrated addition of 150 μmol/L
abscisic acid on day 3, 0.5 g/L leucine and 0.1 g/L penicillin on day 4, the highest lycopene production of 270.3 mg/L was
achieved in the mated fermentation of B. trispora in stirred-tank fermenter. 相似文献
20.
José Miguel Müller Ranulfo Monte Alegre 《World journal of microbiology & biotechnology》2007,23(5):691-695
In this study alginate production by Pseudomonas mendocina in a laboratory-scale fermenter was investigated. In the experiments the effect of temperature (25–31°C) and agitation (500–620 rev min−1) at a constant air flow of 10 v/v/h were evaluated in relation to the rate of glucose bioconversion to alginate using response
surface methodology (RSM). The fermenter configuration was also adapted to a system with a screw mixer and draft tube, due
to the change in rheological characteristics of the fermentation broth. The adjusted model indicates a temperature of 29.1°C
and agitation of 553 rev min−1 for optimum alginate synthesis. In this fermentation system a Y
p/s
of 44.8% was achieved. The alginate synthesized by P. mendocina showed a partially acetylated pattern as previously reported for alginates obtained from other Pseudomonas spp and Azotobacter vinelandii. 相似文献