共查询到20条相似文献,搜索用时 93 毫秒
1.
2.
Thermostable cellulase was produced by Streptomyces sp. T3-1 grown in a 50-l fermenter. Maximum cellulase activity was attained on the fourth day when agitation speeds and aeration rates were controlled at 300 rpm and 0.75 vvm, respectively. Maximum enzyme activities were: 148 IU CMCase ml–1, 45 IU Avicelase ml–1, and 137 IU -glucosidase ml–1 with productivity of 326 IU l–1 h–1, which were 10--32% higher than the values obtained in shake-flask culturesRevisions requested 12 October 2004/1 November 2004; Received received 1 November 2004/14 December 2004 相似文献
3.
The effect of agitation and aeration on the growth and antibiotic production by Xenorhabdus nematophila YL001 grown in batch cultures were investigated. Efficiency of aeration and agitation was evaluated through the oxygen mass
transfer coefficient (K
L
a). With increase in K
L
a, the biomass and antibiotic activity increased. Activity units of antibiotic and dry cell weight were increased to 232 U ml−1 and 19.58 g l−1, respectively, productivity in cell and antibiotic was up more than 30% when K
L
a increased from 115.9 h−1 to 185.7 h−1. During the exponential growth phase, DO concentration was zero, the oxygen supply was not sufficient. So, based on process
analysis, a three-stage oxygen supply control strategy was used to improved the DO concentration above 30% by controlling
the agitation speed and aeration rate. The dry cell weight and activity units of antibiotic were further increased to 24.22 g l−1 and 249 U ml−1, and were improved by 24.0% and 7.0%, compared with fermentation at a constant agitation speed and a constant aeration rate
(300 rev min−1, 2.5 l min−1). 相似文献
4.
Nisin production by Lactococcus lactis subsp. lactisin fed-batch culture was doubled by using a pH feed-back controlled method. Sucrose concentration was controlled at 10 g l–1 giving 5010 IU nisin ml–1 compared to 2660 IU nisin ml–1 in batch culture. 相似文献
5.
Summary The microorganism Aspergillus niger CCRC 31494 can produce an extracellular glucosyltransferase (GTase, EC 2.4.1.24) with a high transglucosylating activity. The maximal enzyme production occurred at initial maltose concentration of 40 gl-1. The microorganism was also grown in a 5-liter jar fermenter for GTase production. It was found that the optimal agitation and aeration rates were 750 rev min-1 and 1.0 l min-1, respectively, and the enzyme production was about 0.25–0.26 units ml-1. 相似文献
6.
Aims: To evaluate the effect of different physicochemical parameters such as agitation, aeration and pH on the growth and nitrile hydratase production by Rhodococcus erythropolis MTCC 1526 in a stirred tank reactor. Methods and Results: Rhodococcus erythropolis MTCC 1526 was grown in 7‐l reactor at different agitation, aeration and controlled pH. The optimum conditions for batch cultivation in the reactor were an agitation rate of 200 rev min?1, aeration 0·5 v/v/m at controlled pH 8. In this condition, the increase in nitrile hydratase activity was almost threefold compared to that in the shake flask. Conclusion: Agitation and aeration rate affected the dissolved‐oxygen concentration in the reactor which in turn affected the growth and enzyme production. Significance and Impact of the Study: Cultivation of R. erythropolis MTCC 1526 in the reactor was found to have significant effect on the growth and nitrile hydratase production when compared to the shake flask. 相似文献
7.
M G Fortina A Acquati P Rossi P L Manachini C Di Gennaro 《Journal of industrial microbiology & biotechnology》1996,17(2):69-72
After induction, seven strains ofBotrytis cinerea released into the culture broth considerable amounts of laccase in a brief production time. The set-up of a suitable production process was studied with a selected strain in a 10-L fermenter. The optimum fermentation conditions were a 3% inoculum with a high degree of sporulation, a simple medium containing 20 g L–1 of glucose and 2 g L–1 of yeast extract at pH 3.5, 2 g L–1 gallic acid as inducer, added after 2 days of growth, an agitation speed of 300 rpm, an aeration rate of 1.2 vvm and a temperature of 24°C. By optimizing the culture conditions, the enzyme activity reached 28 U ml–1 in 5 days with a specific activity of 560 U mg–1 protein. The best procedure to obtain a suitable crude enzyme preparation was concentration of the supernatant medium to 10% of the initial volume by ultrafiltration, followed by a fractional precipitation with ethanol. The optimum pH and temperature for laccase activity were 5.5 and 40°C, respectively, with syringaldazine as the substrate. 相似文献
8.
Ya-Hong Xiong Jian-Zhong Liu Hai-Yan Song Li-Ping Weng Liang-Nian Ji 《World journal of microbiology & biotechnology》2004,20(2):203-206
Combined with u.v. irradiation and the nitrosoguanidine method, selection of biochemical mutants resistant to metabolic inhibitors (2-deoxy-D-glucose, antimycin A, sodium orthovanadate and sodium azide) was a very efficient method for improvement of ribonuclease production by Aspergillus niger. Resistance to sodium azide produced highest RNase production, greatest frequency of positive mutation and shortest sporulation time. The most active strain, Aspergillus niger SA-13-20 resistant to sodium azide, was obtained, which had a 433% increase in RNase production in comparison with the parent strain and had good subculturing stability. Its dynamic characters were similar to those of the parent strain. 相似文献
9.
Arrowroot (Marantha arundinacea) starch as a new low-cost substrate for alkaline protease production
The feasibility of arrowroot (Marantha arundinacea) starch for alkaline protease production using an alkalophilic Bacillus lentus isolate was evaluated in batch fermentations in shake flasks and in a bioreactor under a range of conditions. A new arrowroot starch-casein medium (pH 10.2) was formulated having a composition (%, w/v): arrowroot starch 1, casein 1, sodium succinate 0.25, NH4Cl 0.05, NaCl 0.05, KH2PO4 0.04, K2HPO4 0.03, MgCl2 0.01, yeast extract 0.01 and Na2CO3 1.05. The isolate produced a maximum protease yield (6754.7 U ml–1) in this medium when grown for 72 h at 250 rev/min and 37 °C. Scaling-up studies in a bioreactor showed a 5-fold increase in alkaline protease yields (31899 U ml–1) at a lower production time of 45 h, aeration of 1 v/v/m and agitation of 400 rev/min at 37 °C. 相似文献
10.
The effect of pH, aeration and mixing on the growth and production of carbonyl reductase by Candida viswanathii was investigated in a 6.6-l fermentor. Controlling the pH at 8.0 had a very significant effect on the enzyme production.
Aeration and agitation influenced the dissolved oxygen concentration which in turn affected growth as well as enzyme production.
A maximum carbonyl reductase activity (53 Umg−1) was attained in 24 h under the optimal cultivation conditions of controlled pH at 8.0, aeration rate 1 vvm and an agitation
speed of 250 rpm at 25°C. The enzyme activity was twice as high (56 Umg−1) in the fermentor as compared to a shake flask. Further, the duration of growth and enzyme production in the fermentor was
shortened. Cells cultivated under the optimized conditions were used for the preparative scale reduction of N, N-dimethyl-(3-keto)-2-thienyl-propanamine
to (S)-N, N-dimethyl-(3-hydroxy)-2-thienyl-propanamine, a key intermediate in the production of the important antidepressant drug
(S)-duloxetine. 相似文献
11.
Optimization of S-adenosyl-L-methionine production by Kluyveromyces lactis on whey in batch culture using a mathematical model 总被引:1,自引:0,他引:1
Growth, lactose utilization and S-adenosyl-l-methionine (AdoMet) production by Kluyveromyces lactis AM-65 on whey in batch fermentation were investigated and an unstructured model of the process has been derived. The optimal set of parameters was estimated by fitting the model to experimental results. After incubation for 20 h the optimal fermentation conditions (28.5 °C, pH 5.3, agitation at 270 rpm) resulted in AdoMet production at 1.55 g l–1. 相似文献
12.
Sathyanarayana N. Gummadi Swati Sucharita Dash Santhosh Devarai 《Journal of industrial microbiology & biotechnology》2009,36(5):713-720
The effect of pH, aeration rate, and agitation rate on specific productivity of caffeine demethylase from Pseudomonas sp. was studied in a bioreactor. Maximum specific productivity of caffeine demethylase of 2,214 U g cell dry weight−1 h−1 was obtained at 0.27 vvm, 700 rpm, and pH 7.0. Under these conditions, volumetric oxygen transfer coefficient was 74.2 h−1, indicating that caffeine demethylase production by Pseudomonas sp. was highly oxygen-dependent. Different metabolite formation at different agitation and aeration rates can be used as
a strategy for recovery of pharmaceutically important metabolites from caffeine by manipulation of conditions in a bacterial
culture. This is the first report on production of high levels of caffeine demethylase in bioreactors. 相似文献
13.
Park Heum Gi Lee Kyun Woo Cho Sung Hwoan Kim Hyung Sun Jung Min-Min Kim Hyeung-Sin 《Hydrobiologia》2001,(1):369-374
The freshwater rotifer, Brachionus calyciflorus is one of the live food organisms used for the mass production of larval fish. In this study possibility of obtaining high density cultures of the freshwater rotifer B. calyciflorus were investigated. The two culture systems used differed in their air and dissolved oxygen supplies using three temperatures in each case: 24, 28 and 32 °C. Rotifers were batch-cultured using 5 l-vessels and fed with the freshwater Chlorella. The growth rate of rotifers significantly increased with an increase in temperature. The maximum density of the rotifers with air-supply at 24 °C, 6500 ind. ml–1, was significantly lower than those cultured at 28 and 32 °C, i.e. 8600 and 8100 ind. ml–1, respectively. Dissolved oxygen levels decreased with time and ranged from 0.8 to 1.4 mg l–1 when the density of freshwater rotifer was the highest at each temperature. The highest density (19200 ind. ml–1) of freshwater rotifer was obtained in cultures with a supply of oxygen at 28 °C. Densities of 13500 and 17200 ind. ml–1 were found at 24 and 32 °C, respectively. Levels of NH3-N increased with time and a dramatic increase of NH3-N was observed at high temperatures. Levels of NH3-N at 24, 28 and 32 °C were 13.2, 18.5 and 24.5 mg l–1, respectively. These levels coincided with the highest rotifer density at each of the three temperatures. When rotifers were cultured with an oxygen-supply and pH was adjusted to 7, the maximum density of rotifer reached 33500 ind. ml–1 at 32 °C . These results suggested that high density culture of freshwater rotifer, B. calyciflorus could be achieved under optimal conditions with DO value of exceeding 5 mg l–1 and NH3-N values of lower than 12.0 mg l–1. 相似文献
14.
Nisin production in batch culture and fed-batch cultures (sucrose feeding rates were 6, 7, 8, and 10 g l–1 h–1, respectively) by Lactococcus lactis subsp. lactis ATCC 11454 was investigated. Nisin production showed primary metabolite kinetics, and could be improved apparently by altering the feeding strategy. The nisin titer reached its maximum, 4,185 IU ml–1, by constant addition of sucrose at a feeding rate of 7 g l–1 h–1; an increase in 58% over that of the batch culture (2,658 IU ml–1). Nisin biosynthesis was affected strongly by the residual sucrose concentration during the feeding. Finally, a mathematical model was developed to simulate the cell growth, sucrose consumption, lactic acid production and nisin production. The model was able to describe the fermentation process in all cases. 相似文献
15.
The effect of culture conditions on -endotoxin production by strain S128 of Bacillus thuringiensis H-14 (locally isolated in Egypt) was investigated using a 10l working volume fermenter. Fermentation medium formulated from the inexpensive locally available soya (as a nitrogen source) and molasses (as a carbon source) was used. Aeration, agitation, pH and initial concentration of molasses were chosen as experimental factors and their influence on toxin yield was investigated using 24 central composite experimental design. The mathematical model obtained revealed that the optimal batch cultivation conditions with respect to agitation, pH, and initial concentration of molasses were 325 rev min–1, 7.1 and 2.1% (w/v) respectively. The mathematical model obtained indicated that by increasing the aeration rate over 0.89 v/v per minute the productivity could still be increased. A simulated scaling-up study, in which the Simplex method was applied, is also presented. The results of this investigation could be of great help for large-scale production of a cheap mosquito-larvicide in developing countries where mosquito-borne diseases are still a serious health and economic problem. 相似文献
16.
17.
Selective production of bikaverin in a fluidized bioreactor with immobilized Gibberella fujikuroi 总被引:1,自引:0,他引:1
Escamilla-Silva Eleazar Poggi-Varaldo Héctor De la Torre-Martínez M. Mayra Sanchez Cornejo M.A. Guadalupe Dendooven Luc 《World journal of microbiology & biotechnology》2001,17(5):469-474
The best culture medium composition for the production of bikaverin by Gibberella fujikuroi in shake-flasks, i.e. 100 g glucose l–1; 1 g NH4Cl l–1; 2 g rice flour l–1; 5 g KH2PO4 l–1 and 2.5 g MgSO4 l–1, was obtained through a fractional factorial design and then scaled-up to a fluidized bioreactor. The effects of carbon and nitrogen concentrations, inoculum size, aeration, flow rate and bead sizes on batch bikaverin production using immobilized G. fujikuroi in a fluidized bioreactor were determined by an orthogonal experimental design. Concentrations of up to 6.83 g bikaverin l–1 were obtained when the medium contained 100 g glucose l–1 and 1 g NH4Cl l–1 with an inoculum ratio of 10% v/v, an aeration rate of 3 volumes of air per volume of medium min–1, and a bead size of 3 mm. Based on dry weight, the bikaverin production was 30–100 times larger than found in submerged culture and approximately three times larger than reported for solid substrate fermentation. 相似文献
18.
Statistically based experimental design was employed for the optimization of fermentation conditions for maximum production
of enzyme tannase from Aspergillus niger. Central composite rotatable design (CCRD) falling under response surface methodology (RSM) was used. Based on the results
of ‘one-at-a-time’ approach in submerged fermentation, the most influencing factors for tannase production from A. niger were concentrations of tannic acid and sodium nitrate, agitation rate and incubation period. Hence, to achieve the maximum
yield of tannase, interaction of these factors was studied at optimum production pH of 5.0 by RSM. The optimum values of parameters
obtained through RSM were 5% tannic acid, 0.8% sodium nitrate, 5.0 pH, 5 × 107 spores/50mL inoculum density, 150 rpm agitation and incubation period of 48 h which resulted in production of 19.7 UmL−1 of the enzyme. This activity was almost double as compared to the amount obtained by ‘one-at-a-time’ approach (9.8 UmL−1). 相似文献
19.
Medeiros Adriane B.P. Pandey Ashok Christen Pierre Fontoura Paulo S.G. de Freitas Renato J.S. Soccol Carlos R. 《World journal of microbiology & biotechnology》2001,17(8):767-771
Studies were carried out for the production of aroma compounds by Kluyveromyces marxianus grown on cassava bagasse in solid state fermentation using packed bed reactors, testing two different aeration rates. Respirometric analysis was used to follow the growth of the culture. Headspace analysis of the culture by gas chromatography showed the production of 11 compounds, out of which nine were identified. Ethyl acetate, ethanol and acetaldehyde were the major compounds produced. Lower aeration rate (0.06l h–1 g–1 of initial dry matter) increased total volatile (TV) production and the rate of production was also increased at this aeration rate. Using an aeration rate of 0.06l h–1 g–1 maximum TV concentrations were reached at 24 h and at 40 h with 0.12l h–1 g–1. 相似文献
20.
Bo-Hwa Lee Bo-Kyung Kim You-Jung Lee Chung-Han Chung Jin-Woo Lee 《Enzyme and microbial technology》2010,46(1):127
Rice bran and yeast extract were found to be the best combination of carbon and nitrogen sources for the production of carboxymethycellulase (CMCase) by Bacillus subtilis subsp. subtlis A-53. Optimal concentrations of rice bran and yeast extract for the production of CMCase were 5.0% (w/v) and 0.10% (w/v), respectively. Optimal temperature and initial pH of medium for cell growth of B. subtilus subsp. subtilis A-53 were 35 °C and 7.3, whereas those for the production of CMCase by B. subtilus subsp. subtilis A-53 were 30 °C and 6.8. Optimal agitation speed and aeration rate in a 7 L bioreactor were 300 rpm and 1.0 vvm, respectively. The optimal agitation speed and aeration rate for the production of CMCase by B. subtilus subsp. subtilis A-53 were lower than those for cell growth. The highest productions of CMCase by B. subtilus subsp. subtilis A-53 in 7 and 100 L bioreactors were 150.3 and 196.8 U mL−1, respectively. 相似文献