共查询到20条相似文献,搜索用时 31 毫秒
1.
Mauro Moresi Eugenio Parente Angelo Mazzatura 《Applied microbiology and biotechnology》1991,36(3):320-323
Summary Gluconic acid production from corn starch hydrolysates by immobilised mycelia of Aspergillus niger was studied in a laboratory-scale stirred fermentor at different concentrations of glucose (S
0) and dissolved oxygen (DO) in the culture broth. Its evolution was simulated quite well by applying the same unstructured model set up in previous experiments using stirred and airlift fermentors. In particular, increasing S
0 in the range 70–160 g/l, although uninfluential upon the yield coefficient, resulted in an exponential decrease in the gluconic acid formation rate constant. Nevertheless, the greater the oxygen transfer rate used in the fermentor, the smaller the inhibitor effect of the higher concentrations of glucose on gluconate productivity became. This was achieved by enriching the inlet air with pure oxygen so as to maintain the DO level above 75% saturation throughout the fermentation.
Offprint requests to: M. Moresi 相似文献
2.
Vineeta Singh Mahvish Khan Saif Khan C. K. M. Tripathi 《Applied microbiology and biotechnology》2009,82(2):379-385
Artificial neural network (ANN) and genetic algorithm (GA) were applied to optimize the medium components for the production
of actinomycinV from a newly isolated strain of Streptomyces triostinicus which is not reported to produce this class of antibiotics. Experiments were conducted using the central composite design
(CCD), and the data generated was used to build an artificial neural network model. The concentrations of five medium components
(MgSO4, NaCl, glucose, soybean meal and CaCO3) served as inputs to the neural network model, and the antibiotic yield served as outputs of the model. Using the genetic
algorithm, the input space of the neural network model was optimized to find out the optimum values for maximum antibiotic
yield. Maximum antibiotic yield of 452.0 mg l−1 was obtained at the GA-optimized concentrations of medium components (MgSO4 3.657; NaCl 1.9012; glucose 8.836; soybean meal 20.1976 and CaCO3 13.0842 gl−1). The antibiotic yield obtained by the ANN/GA was 36.7% higher than the yield obtained with the response surface methodology
(RSM). 相似文献
3.
Fengjie Cui Zhiqiang Liu Yin Li Lifeng Ping Liying Ping Zhicai Zhang Lin Lin Ying Dong Daming Huang 《Biotechnology and Bioprocess Engineering》2010,15(2):299-307
The Doehlert experimental design was used to optimize the production of mycelial biomass and exopolymer from Hericium erinaceus CZ-2 in this study. Statistical analysis showed that the linear and quadric terms of 3 variables: corn flour, yeast extract,
and corn steep liquor had significant effects. The optimized combination of these 3 variables was confirmed through validation
experiments. The optimal conditions for higher production of mycelial biomass (19.92 g/L) were estimated when the media composition
concentrations were set as: 30.85 g/L, corn flour; 2.81 g/L, yeast extract; 16.9 mL/L, corn steep liquor; 10 g/L, glucose;
1 g/L, KH2PO4; and 0.5 g/L, MgSO4·7H2O; while a maximal exo-polymer yield (1.653 g/L) could be achieved when setting concentrations of: 32.71 g/L, corn flour;
2.35 g/L, Yeast extract; 14.42 mL/L, Corn steep liquor; 10 g/L, glucose; 1 g/L, KH2PO4; and 0.5 g/L, MgSO4·7H2O. The upscale production was also investigated using a 15 L fermentor using the optimized medium. 相似文献
4.
J. L. Malfait D. J. Wilcox D. G. Mercer L. D. Barker 《Biotechnology and bioengineering》1981,23(4):863-877
Results of pilot plant studies using a glass airlift fermentation device (55 liter fermentation volume) have proven the relative merits of such a system in the fermentation of a filamentous mold, Monascus purpureus, on 4% (w/w) starch media. The resultant overall yield of cell mass (Yx/s) of 0.38 was an appreciable increase over the 0.32 obtained with a pilot scale stirred tank fermentor previously studied. Power requirements of the airlift fermentor were approximately 50% of those for the mechanically agitated system. The lack of mechanical shear in the airlift system provides a more gentle environment or the cultivation of organisms than does the high degree of shear prevalent in the mechanically agitated vessels. Mass transfer of oxygen to the aqueous phase of the fermentation volume is improved significantly through use of the airlift device. Mass transfer coefficients in the range of 200 reciprocal hr were obtained to approximately 80 reciprocal hr in the stirred tank fermentor. 相似文献
5.
Aims: Development and optimization of an efficient and inexpensive biotransformation process for ginsenoside compound K production by Paecilomyces bainier sp. 229. Methods and Results: We have determined the optimum culture conditions required for the efficient production of ginsenoside compound K by P. bainier sp. 229 via biotransformation of ginseng saponin substrate. The optimal medium constituents were determined to be: 30 g sucrose, 30 g soybean steep powder, 1 g wheat bran powder, 1 g (NH4)2SO4, 2 g MgSO4·7H2O and 1 g CaCl2 in 1 l of distilled water. An inoculum size of 5–7·5% with an optimal pH range of 4·5–5·5 was essential for high yield. Conclusions: The Mol conversion quotient of ginseng saponins increased from 21·2% to 72·7% by optimization of the cultural conditions. Scale‐up in a 10 l fermentor, under conditions of controlled pH and continuous air supply in the optimal medium, resulted in an 82·6% yield of ginsenoside compound K. Significant and Impact of the Study: This is the first report on the optimization of culture conditions for the production of ginsenoside compound K by fungal biotransformation. The degree of conversion is significantly higher than previous reports. Our method describes an inexpensive, rapid and efficient biotransformation system for the production of ginsenoside compound K. 相似文献
6.
Fermentations of Xanthomonas campestris, NRRL B-1459, were carried out in a bubble column fermentor (BCF) and in a stirred tank fermentor (STF) to allow comparison of representative variables measured during the microbial growth and the gum production. The microbial growth phase was described by a logistic rate equation where maximum cell concentration was provided by nitrogenous compounds balance. The average value of the maximum specific growth rate was higher in the bubble column (μ M =0.5 h?1) than in the stirred reactor (μ M =0.4 h?1). The upper values of xanthan yield (Y g-x =0.65 kg xanthan/kg glucose; Y O 2?x xanthan/kg oxygen) and specific production rate (q x =0.26 kg xanthan/kg biomass · h) were measured when the oxygen transfer coefficient was kept up above 80 h?1 in the STF fermentor. In the bubble column the fermentation achieved in the same culture medium lasts two times longer than in the stirred aerated tank; this was attributed to the low value of the oxygen transfer coefficient (K L a =20 h?1) at the beginning of the gum synthesis phase. The results obtained in the stirred tank were the basis to estimate the optimal biomass concentration which enables to achieve a culture in non-limiting oxygen transfer conditions. Nevertheless, the transfer characteristics were more homogeneous in the bubble column than in the stirred tank where dead stagnant zones were observed. This is of primary importance when establishing fermentation kinetics models. 相似文献
7.
The dependence on salt concentration of steady-state total and irreversible adsorption of T2r phage on isolated bacterial
cell walls was studied. Solutions of NaCl, KCl and MgSO4 of different molarity were used and a difference between the total and the irreversible adsorption at lower concentration
of NaCl and KCl, but not in MgSO4 solutions, was found. The effect of KCl on total adsorption was similar to that of MgSO4 in which case the adsorption begins at lower molar concentrations than with NaCl. 相似文献
8.
Summary The effect of lytic enzymes of Micromonospora AS on isolated cell walls and intact or heat killed cells of Candida utilis was investigated. Several substances normally used as stabilizers during protoplast formation were tested for their effect on the lytic action of strepzyme M on intact and dead cells: NaCl and KCl markedly inhibited lysis, sucrose only to 40%. Sorbitol and MgSO4 have no inhibitory effect. MgSO4 was selected for further research as it was found to protect the protoplasts. Phosphate buffer pH 6.8 should not be used at concentrations above 0.01 m. When grown submerged in shaking flasks or in pilot fermentation tanks, in liquid medium containing yeast cells and salts, Micromonospora AS gave the highest yield of lytic enzymes. The strepzyme M preparation is thermolabile. 相似文献
9.
The waters in which saline-water mosquito larvae are found can differ substantially in the types and ratios of ions present. Inland saline waters are more likely to contain high levels of MgSO4 than are coastal ones. We undertook a study to determine if Aedes dorsalis, an inland species, is more tolerant of MgSO4 than Aedes taeniorhynchus, a coastal one. The effects of MgSO4 concentration were tested on all of the aquatic life stages of both species. Egg hatching was adversely affected at higher concentrations yet eggs would hatch in waters in which larvae could not survive. Younger larvae were more sensitive to MgSO4 toxicity than the third and fourth instars. No differences in larval tolerance to MgSO4 were observed between the two species indicating that neither species is ‘preadapted’ for MgSO4 tolerance. Pupae of both species were completely insensitive to the levels of MgSO4 tested. Larvae of A. taeniorhynchus reared in MgSO4-rich media showed substantial increases in tolerance to subsequent MgSO4 stress, possibly through an induction of Mg2+ and SO42? transport systems. Increased tolerance to MgSO4 required the presence of both Mg2+ and SO42? in the rearing medium. When larvae of both species were subjected to steadily increasing concentrations of seawater, A taeniorhynchus survived much higher concentrations than did A. dorsalis. Therefore, while the process of induction is very important in extending the ionic range over which larvae can survive and develop, the possible ionic range for each species is finite. The differences in ionic range for each species probably accounts for the diversity of ionic tolerance and species distribution observed in the field. 相似文献
10.
在摇瓶和5 L发酵罐中研究了溶氧 (DO) 对Blakeslea trispora分批发酵生产β-胡萝卜素的影响,总结了5 L发酵罐中β-胡萝卜素发酵过程中溶氧的变化规律.结果表明,当500 mL摇瓶装液量为50 mL,转速为240 r/min条件下发酵生产β-胡萝卜素产量最大,达到3.416 g/L; 5 L发酵罐中,在搅拌转速为1 000 r/min,通气量为1.5 vvm的条件下,β-胡萝卜素的产量可达到3.712 g/L,略高于摇瓶,这可能是由于5 L发酵罐中的气液传递和混合状况好于摇瓶,促进了产物的合成. 相似文献
11.
Macronutrients influence the cell biomass yield and anthocyanin production in plant cell suspension cultures. However, different species respond differently for different nutrient concentrations. In this study, we tested the effect of different concentrations of macronutrients on the cell cultures of Melastoma malabathricum L. The results showed that the addition of NH4NO3 did not show any increment in the cell biomass but it enhanced the anthocyanin accumulation. Results indicated that CaCl2.2H2O and MgSO4.7H2O played a more important role in anthocyanin accumulation than the cell growth of M. malabathricum. However, the presence or absence of KNO3 and KH2PO4 did not show any effect on either the cell biomass or the anthocyanin production. 相似文献
12.
J. M Monteagudo J. Rincn L. Rodríguez J. Fuertes A. Moya 《Engineering in Life Science》1993,13(2):103-110
Optimization studies have been carried out for the production of L-lactic acid from the fermentation of beet molasses by Lactobacillus delbrueckii. A PLACKETT -BURMAN Design and a Central Composite Design have been used to determine the most suitable nutrient medium for obtaining a maximum cell concentration. A second-order polynomial empirical model relating both the cell and nutrient concentrations was formulated. The variables selected for the study were Yeast Extract, Peptone, Tween 80 (antifoam), MgSO4 · 7H2O, MnSO4·4H2O, FeSO4 · 7H2O and K2HPO4/KH2PO4. Among them, only Yeast Extract and Peptone were found to significantly affect the cell concentration. A maximum cell yield was found when the concentrations of Yeast Extract and Peptone were, respectively, 5.31 g/l and 5.08 g/l. All conclusions are restricted to the experimental range studied. 相似文献
13.
Experiments were performed in a pilot scale 0.30 m3 conventional stirred-tank fermentor using water, air/water, and air/K2SO4 solutions. Both single- and two-stage impeller systems were investigated. Overall and tank-side coefficients for heat transfer from a 0.012 m diameter coil were measured for a range of impeller speeds and superficial gas velocities. Power input, bubble size, and gas hold-up were also determined. An analysis of the experimental results indicates that previously published correlations for single-phase heat transfer in stirred tanks (of the type: Nu = C(Re)α(Pr)β) are not applicable for single- or multiimpeller gas/liquid systems. The introduction of air alters the mixing pattern significantly, affecting both average and local tank-side heat transfer coefficients. Power input and gas hold-up are suggested as the major correlating parameters for the determination of tank-side heat transfer coefficients. 相似文献
14.
Gerardo Saucedo-Castañeda B. K. Lonsane Jean-Marie Navarro Sevastianos Roussos 《Applied microbiology and biotechnology》1992,37(5):580-582
Summary The rate of aeration of the medium in a solid state fermentation system for biomass production by Schwanniomyces castellii in a large column fermentor was found to influence the gradient of biomass yield at different bed heights. The variations were lower with a higher rate of aeration. These trends were used to formulate a successful strategy to ensure equal biomass yield at all the bed heights by controlling the level of CO2 at about 2% in exhaust air from the fermentor.
Correspondence to: B. K. Lonsane 相似文献
15.
Eutimio Gustavo Fernández Núñez Jaci Leme Letícia de Almeida Parizotto Wagner Antonio Chagas Alexandre Gonçalves de Rezende Bruno Labate Vale da Costa Daniela Cristina Ventini Monteiro Vera Lucia Lopes Boldorini Soraia Attie Calil Jorge Renato Mancini Astray Carlos Augusto Pereira Celso Pereira Caricati Aldo Tonso 《Cytotechnology》2014,66(4):605-617
This work focused on determining the effect of dissolved oxygen concentration (DO) on growth and metabolism of BHK-21 cell line (host cell for recombinant proteins manufacturing and viral vaccines) cultured in two stirred tank bioreactors with different aeration-homogenization systems, as well as pH control mode. BHK-21 cell line adapted to single-cell suspension was cultured in Celligen without aeration cage (rotating gas-sparger) and Bioflo 110, at 10, 30 and 50 % air saturation (impeller for gas dispersion from sparger-ring). The pH was controlled at 7.2 as far as it was possible with gas mixtures. In other runs, at 30 and 50 % (DO) in Bioflo 110, the cells grew at pH controlled with CO2 and NaHCO3 solution. Glucose, lactate, glutamine, and ammonium were quantified by enzymatic methods. Cell concentration, size and specific oxygen consumption were also determined. When NaHCO3 solution was not used, the optimal DOs were 10 and 50 % air saturation for Celligen and Bioflo 110, respectively. In this condition maximum cell concentrations were higher than 4 × 106 cell/mL. An increase in maximum cell concentration of 36 % was observed in batch carried out at 30 % air saturation in a classical stirred tank bioreactor (Bioflo 110) with base solution addition. The optimal parameters defined in this work allow for bioprocess developing of viral vaccines, transient protein expression and viral vector for gene therapy based on BHK-21 cell line in two stirred tank bioreactors with different agitation–aeration systems. 相似文献
16.
Jared E. Fein Bogdan C. Zawadzki Hugh G. Lawford G. Ross Lawford 《Applied microbiology》1983,45(6):1899-1904
Growth of Zymomonas mobilis ATCC 29191 and CP4 in a continuous stirred tank fermentor resulted in the selection of stable flocculating variants. Factors responsible for enhancing the system pressures selective for the morphological variants were identified. By incorporating some modifications into the design of the fermentor, it was possible to achieve steady-state operation of the chemostat with both wild-type and flocculating strains. Biochemical and microscopic studies were performed to elucidate the mechanism of flocculation in Z. mobilis. 相似文献
17.
Xuefeng Wu Shaotong Jiang Mo Liu Lijun Pan Zhi Zheng Shuizhong Luo 《Journal of industrial microbiology & biotechnology》2011,38(4):565-571
Semicontinuous fermentation using pellets of Rhizopus oryzae has been recognized as a promising technology for l-lactic acid production. In this work, semicontinuous fermentation of R. oryzae AS 3.819 for l-lactic acid production has been developed with high l-lactic acid yield and volumetric productivity. The effects of factors such as inoculations, CaCO3 addition time, and temperature on l-lactic acid yield and R. oryzae morphology were researched in detail. The results showed that optimal fermentation conditions for the first cycle were: inoculation
with 4% spore suspension, CaCO3 added to the culture medium at the beginning of culture, and culture temperature of 32–34°C. In orthogonal experiments, high
l-lactic acid yield was achieved when the feeding medium was (g/l): glucose, 100; (NH4)2SO4, 2; KH2PO4, 0.1; ZnSO4·7H2O, 0.33; MgSO4·7H2O, 0.15; CaCO3, 50. Twenty cycles of semicontinuous fermentation were carried out in flask culture. l-lactic acid yield was 78.75% for the first cycle and 80–90% for the repeated cycles; the activities of lactate dehydrogenases
(LDH) were 7.2–9.2 U/mg; fermentation was completed in 24 h for each repeated cycle. In a 7-l magnetically stirred fermentor,
semicontinuous fermentation lasted for 25 cycles using pellets of R. oryzae AS 3.819 under the optimal conditions determined from flask cultures. The final l-lactic acid concentration (LLAC) reached 103.7 g/l, and the volumetric productivity was 2.16 g/(l·h) for the first cycle;
in the following 19 repeated cycles, the final LLAC reached 81–95 g/l, and the volumetric productivities were 3.40–3.85 g/(l·h). 相似文献
18.
Calcitriol is an important drug used for treating osteoporosis, which can be produced from vitamin D3. The current method of producing calcitriol from vitamin D3 during cultivation of microbial cells results in low yields of calcitriol and high purification costs. Therefore, in this study, the steps of cell cultivation and bioconversion of vitamin D3 to calcitriol were separated. Cells of Pseudonocardia sp. KCTC 1029BP were utilized as a whole cell catalyst to produce a high level and yield of calcitriol from vitamin D3. In addition, the effects of bioconversion buffers, cyclodextrins, and metal salts on the production of calcitriol were comparatively examined and selected for incorporation in the bioconversion medium, and their compositions were statistically optimized. The optimal bioconversion medium was determined as consisting of 15 mM Trizma base, 25 mM sodium succinate, 2 mM MgSO4, 0.08 % β-cyclodextrin, 0.1 % NaCl, 0.2 % K2HPO4, and 0.03 % MnCl2. Using this optimal bioconversion medium, 61.87 mg/L of calcitriol, corresponding to a 30.94 % mass yield from vitamin D3, was produced in a 75-L fermentor after 9 days. This calcitriol yield was 3.6 times higher than that obtained using a bioconversion medium lacking β-cyclodextrin, NaCl, K2HPO4, and MnCl2. In conclusion, utilizing whole cells of Pseudonocardia sp. KCTC 1029BP together with the optimal bioconversion medium markedly enhanced the production of calcitriol from vitamin D3. 相似文献
19.
《Enzyme and microbial technology》1987,9(9):559-563
Continuous ethanol production in a one-stage continuous stirred tank fermentor without recycle was carried out using a yeast strain Saccharomyces cerevisiae. Different dilution rates were used. Cell and ethanol concentrations in the culture medium decreased with increasing dilution rates, and the maximum value of 3.0 g l−1h−1was found at a dilution rate of 0.340 h−1. Specific ethanol productivities increased as dilution rates were increased, and the highest value appeared at about the same dilution rate as that for the maximum fermentor productivity. A material balance equation, which relates total amount of spent medium to cell synsthesis, ethanol production, and overall maintenance, was introduced. The cellular yield and overall maintenance coefficients increased with increasing dilution rates. The fraction of limiting substrate utilized for overall maintenance, which includes the limiting substrate spent for purposes other than cell synthesis and ethanol production, decreased with increasing dilution rates. The non-product associated substrate utilization can be minimized if correct dilution rate is chosen. 相似文献
20.
对从深海沉积物宏基因组文库中获得的产低温脂肪酶基因工程菌LIP001进行了发酵条件优化。通过单因素试验对LIP001产脂肪酶的主要影响条件进行了探讨,确定了培养条件为30℃、pH7.0、接种量5%、装液量50ml。在单因素的基础上通过正交试验优化了影响重组菌LIP001产酶主要因素:橄榄油、酵母粉、磷酸盐、MgSO4,确定了培养基为橄榄油1%、酵母粉0.5%、蛋白胨1%、硫酸铵0.5%、磷酸盐0.5%、MgSO4为0.2%、氯霉素12.5μg/ml,优化后的脂肪酶活为1980U/ml,比优化前提高了54.7%,为大规模发酵奠定了基础。采用5升发酵罐方法试验,酶活达到2420U/ml。 相似文献