共查询到20条相似文献,搜索用时 15 毫秒
1.
Xin Zhao Cuimin Hu Siguo Wu Hongwei Shen Zongbao K. Zhao 《Journal of industrial microbiology & biotechnology》2011,38(5):627-632
Microbial lipid is a potential alternative feedstock for the biodiesel industry. New culture strategies remain to be developed
to improve the economics of microbial lipid technology. This work describes lipid production by the oleaginous yeast Rhodosporidium toruloides Y4 using a 15-l bioreactor with different substrate feeding strategies. Among these strategies, the intermittent feeding
mode gave a lipid productivity of 0.36 g l−1 h−1, whereas the constant glucose concentration II (CC-II) mode gave the highest lipid productivity of 0.57 g l−1 h−1. The repeated fed-batch mode according to the CC-II mode was performed with a duration time of 358 h, and the overall lipid
productivity was 0.55 g l−1 h−1. Our results suggested that substrate feeding modes had a great impact on lipid productivity and that the repeated fed-batch
process was the most appealing method by which to enhance microbial lipid production. 相似文献
2.
Constant medium feeding rate and intermittent fed-batch fermentation strategies were investigated aiming to increase the yields
of γ-decalactone production by Yarrowia lipolytica, using methyl ricinoleate as substrate and ricinoleic acid source. The accumulation of another compound, 3-hydroxy-γ-decalactone,
was also analyzed since it derives from the direct precursor of γ-decalactone thereby providing information about the enzymatic
activities of the pathway. Both strategies were compared with the traditional batch mode in terms of overall productivity
and yield in respect to the substrate. Although the productivity of γ-decalactone was considerably higher in the batch mode
(168 mg l−1 h−1), substrate conversion to lactone (73 mg γ-decalactone g−1) was greater in the intermittent fed-batch giving 6.8 g γ-decalactone l−1. This last strategy therefore has potential for γ-decalactone production at an industrial level. 相似文献
3.
Beauvericin (BEA) is a cyclic hexadepsipeptide mycotoxin with notable phytotoxic and insecticidal activities. Fusarium redolens Dzf2 is a highly BEA-producing fungus isolated from a medicinal plant. The aim of the current study was to develop a simple
and valid kinetic model for F. redolens Dzf2 mycelial growth and the optimal fed-batch operation for efficient BEA production. A modified Monod model with substrate
(glucose) and product (BEA) inhibition was constructed based on the culture characteristics of F. redolens Dzf2 mycelia in a liquid medium. Model parameters were derived by simulation of the experimental data from batch culture.
The model fitted closely with the experimental data over 20–50 g l−1 glucose concentration range in batch fermentation. The kinetic model together with the stoichiometric relationships for biomass,
substrate and product was applied to predict the optimal feeding scheme for fed-batch fermentation, leading to 54% higher
BEA yield (299 mg l−1) than in the batch culture (194 mg l−1). The modified Monod model incorporating substrate and product inhibition was proven adequate for describing the growth kinetics
of F. redolens Dzf2 mycelial culture at suitable but not excessive initial glucose levels in batch and fed-batch cultures. 相似文献
4.
Haijun Wu Qingbiao Li Rui Lu Yuanpeng Wang Xiaoling Zhuang Ning He 《Journal of industrial microbiology & biotechnology》2010,37(11):1203-1209
The constant-rate fed-batch production of the polygalacturonic acid bioflocculant REA-11 was studied. A controlled sucrose-feeding
strategy resulted in a slight improvement in biomass and a 7% reduction in flocculating activity compared with the batch process.
When fed with a 3 g l−1 urea solution, the flocculating activity was enhanced to 720 U ml−1 in 36 h. High cell density (2.12 g l−1) and flocculating activity (820 U ml−1) were obtained in a 10-l fermentor by feeding with a sucrose-urea solution, with values of nearly two times and 50% higher
than those of the batch process, respectively. Moreover, the residual sucrose declined to 2.4 g l−1, and residual urea decreased to 0.03 g l−1. Even higher flocculating activity of 920 U ml−1 and biomass of 3.26 g l−1 were obtained by feeding with a sucrose-urea solution in a pilot scale fermentation process, indicating the potential industrial
utility of this constant-rate feeding strategy in bioflocculant production by Corynebacterium glutamicum. 相似文献
5.
Chou-Chiang Kuo Ching-An Lin Jing-Yi Chen Ming-Tse Lin Kow-Jen Duan 《Biotechnology letters》2009,31(11):1723-1727
Batch and fed-batch fermentation processes were employed to culture an alkalophilic Bacillus sp. for the production of cyclodextrin glucanotransferase (CGTase). CGTase production was repressed by glucose and induced
by soluble starch. By fed-batch fermentation, a CGTase activity up to 56 unit ml−1 with 65 g dry cells l−1 were achieved. The CGTase activity and cell density were increased 360 and 510%, respectively, from those values achieved
with batch fermentation. 相似文献
6.
Kinetic models for astaxanthin production by high cell density mixotrophic culture of the microalga Haematococcus pluvialis 总被引:3,自引:0,他引:3
High cell density cultivation of Haematococcus pluvialis for astaxanthin production was carried out in batch and fed-batch modes in 3.7-L bioreactors with stepwise increased light
intensity control mode. A high cell density of 2.65 g L−1 (batch culture) or 2.74 g L−1 (fed-batch culture) was obtained, and total astaxanthin production in the fed-batch culture (64.36 mg L−1) was about 20.5% higher than in the batch culture (53.43 mg L−1). An unstructured kinetic model to describe the microalga culture system including cell growth, astaxanthin formation, as
well as sodium acetate consumption was proposed. Good agreement was found between the model predictions and experimental data.
The models demonstrated that the optimal light intensity for mixotrophic growth of H. pluvialis in batch or fed-batch cultures in a 3.7-L bioreactor was 90–360 μmol m−2 s−1, and that the stepwise increased light intensity mode could be replaced by a constant light intensity mode.
Received 24 December 1998/ Accepted in revised form 23 April 1999 相似文献
7.
Lang YJ Bai L Ren YN Zhang LH Nagata S 《Extremophiles : life under extreme conditions》2011,15(2):303-310
Using ectoine-excreting strain Halomonas salina DSM 5928T, we developed a new process for high-efficiency production of ectoine, which involved a combined process of batch fermentation
by growing cells and production by resting cells. In the first stage, batch fermentation was carried out using growing cells
under optimal fermentation conditions. The second stage was the production phase, in which ectoine was synthesized and excreted
by phosphate-limited resting cells. Optimal conditions for synthesis and excretion of ectoine during batch fermentation in
a 10 l fermentor were 0.5 mol l−1 NaCl and an initial monosodium glutamate concentration of 80 g l−1 respectively. The pH was adjusted to 7.0 and the temperature was maintained at 33°C. In phosphate-limited resting cells medium,
monosodium glutamate and NaCl concentration was 200 g l−1 and 0.5 mol l−1, respectively, as well as pH was 7.0. The total concentration of ectoine produced was 14.86 g l−1, the productivity and yield of ectoine was 7.75 g l−1 day−1 and 0.14 g g−1, respectively, and the percentage of ectoine excreted was 79%. These levels of ectoine production and excretion are the highest
reported to date. 相似文献
8.
Xiao-Hai Feng Fei Chen Hong Xu Bo Wu Jun Yao Han-Jie Ying Ping-Kai Ouyang 《Bioprocess and biosystems engineering》2010,33(9):1077-1085
Propionic acid was produced in a multi-point fibrous-bed (MFB) bioreactor by Propionibacterium freudenreichii CCTCC M207015. The MFB bioreactor, comprising spiral cotton fiber packed in a modified 7.5-l bioreactor, was effective for
cell-immobilized propionic acid production compared with conventional free cell fermentation. Batch fermentations at various
glucose concentrations were investigated in the MFB bioreactor. Based on analysis of the time course of production, a fed-batch
strategy was applied for propionic acid production. The maximum propionic acid concentration was 67.05 g l−1 after 496 h of fermentation, and the proportion of propionic acid to total organic acids was approximately 78.28% (w/w).
The MFB bioreactor exhibited excellent production stability during batch fermentation and the propionic acid productivity
remained high after 78 days of fermentation. 相似文献
9.
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
10.
Preparation of lipophilic alkyl (hydroxy)benzoates by solvent-free lipase-catalyzed esterification and transesterification 总被引:1,自引:0,他引:1
Agal-fermentation-based microbio-diesel production was realized through high-cell-density fermentation of Chlorella protothecoides and efficient transesterification process. Cell density achieved was 16.8 g l−1 in 184 h and 51.2 g l−1 in 167 h in a 5-l bioreactor by performing preliminary and improved fed-batch culture strategy, respectively. The lipid content
was 57.8, 55.2, and 50.3% of cell dry weight from batch, primary, and improved fed-batch culture in 5-l bioreactor. Transesterification
was catalyzed by immobilized lipase, and the conversion rate reached up to 98%. The properties of biodiesel from Chlorella were comparable to conventional diesel fuel and comply with US standard for Biodiesel. In a word, the approach including
high-density fermentation of Chlorella and enzymatic transesterification process were set up and proved to be a promising alternative for biodiesel production. 相似文献
11.
Xiao-Yu Dong Zhi-Long Xiu Shuang Li Ying-Min Hou Dai-Jia Zhang Chun-Sheng Ren 《Biotechnology letters》2010,32(9):1245-1250
Dielectric barrier discharge plasma was used to generate a stable strain of Klebsiella pneumoniae (designated to as Kp-M2) with improved 1,3-propanediol production. The specific activities of glycerol dehydrogenase, glycerol
dehydatase and 1,3-propanediol oxidoreductase in the crude cell extract increased from 0.11, 9.2 and 0.15 U mg−1, respectively, for wild type to 0.67, 14.4 and 1.6 U mg−1 for Kp-M2. The glycerol flux of Kp-M2 was redistributed with the flux to the reductive pathway being increased by 20% in
batch fermentation. The final 1,3-propanediol concentrations achieved by Kp-M2 in batch and fed-batch fermentations were 19.9
and 76.7 g l−1, respectively, which were higher than those of wild type (16.2 and 49.2 g l−1). The results suggested that dielectric barrier discharge plasma could be used as an effective approach to improve 1,3-propanediol
production in K. pneumoniae. 相似文献
12.
Kim YS Lee JH Kim NH Yeom SJ Kim SW Oh DK 《Applied microbiology and biotechnology》2011,90(2):489-497
In the fed-batch culture of glycerol using a metabolically engineered strain of Escherichia coli, supplementation with glucose as an auxiliary carbon source increased lycopene production due to a significant increase in
cell mass, despite a reduction in specific lycopene content. l-Arabinose supplementation increased lycopene production due to increases in cell mass and specific lycopene content. Supplementation
with both glucose and l-arabinose increased lycopene production significantly due to the synergistic effect of the two sugars. Cell growth by the
consumption of carbon sources was related to endogenous metabolism in the host E. coli. Supplementation with l-arabinose stimulated only the mevalonate pathway for lycopene biosynthesis and supplementation with both glucose and l-arabinose stimulated synergistically only the mevalonate pathway. In the fed-batch culture of glycerol with 10 g l−1 glucose and 7.5 g l−1
l-arabinose, the cell mass, lycopene concentration, specific lycopene content, and lycopene productivity after 34 h were 42 g l−1, 1,350 mg l−1, 32 mg g cells−1, and 40 mg l−1 h−1, respectively. These values were 3.9-, 7.1-, 1.9-, and 11.7-fold higher than those without the auxiliary carbon sources,
respectively. This is the highest reported concentration and productivity of lycopene. 相似文献
13.
Large-scale transient gene expression of recombinant protein in mammalian cells requires a great amount of plasmid. An economical
method for large-scale plasmid preparation, based on fed-batch fermentation and an improved plasmid extraction process, has
been established. Fed-batch growth of E. coli was carried out in 5 l bioreactor by controlling the glucose concentration below 1 g l−1 after the feeding was started. Plasmid yields of 490 and 580 mg l−1 were achieved with two strains of E. coli cells bearing pCEP4-EGFP and pID-EG respectively, representing 24.5- and 26-fold increases over those of the batch culture
in shake-flask. To improve the procedure for large-scale preparation of plasmid DNA, addition of RNase to resuspension buffer
and ultrafiltration of clarified lysate were adopted, and the quality of the resultant plasmid was comparable to that of commercial
kit as disclosed in the small-scale transient transfection. This plasmid production process has great potential in the large
scale transient gene expression which needs a large quantity of plasmid DNA. 相似文献
14.
Phycocyanin production by high cell density cultivation of Spirulina platensis in batch and fed-batch modes in 3.7-L bioreactors with a programmed stepwise increase in light intensity program was investigated.
The results showed that the cell density in fed-batch culture (10.2 g L−1) was 4.29-fold that in batch culture (2.38 g L−1), and the total phycocyanin production in the fed-batch culture (0.795 g L−1) was 3.05-fold that in the batch culture (0.261 g L−1). An unstructured kinetic model to describe the microalga culture system including cell growth, phycocyanin formation, as
well as glucose consumption was proposed. The data fitted the models well (r
2 > 0.99). Furthermore, based on the kinetic models, the potential effects of light limitation and photoinhibition on cell
growth and phycocyanin formation can be examined in depth. The models demonstrated that the optimal light intensity for mixotrophic
growth of Spirulina platensis in batch or fed-batch cultures using a 3.7-L bioreactor was 80160 μE m−2 s−1, and the stepwise increase in light intensity can be replaced by a constant light intensity mode.
Received 28 July 1998/ Accepted in revised form 8 October 1998 相似文献
15.
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
16.
Lakkana Laopaiboon Pornthap Thanonkeo Prasit Jaisil Pattana Laopaiboon 《World journal of microbiology & biotechnology》2007,23(10):1497-1501
Sweet sorghum juice supplemented with 0.5% ammonium sulphate was used as a substrate for ethanol production by Saccharomyces cerevisiae TISTR 5048. In batch fermentation, kinetic parameters for ethanol production depended on initial cell and sugar concentrations.
The optimum initial cell and sugar concentrations in the batch fermentation were 1 × 108 cells ml−1 and 24 °Bx respectively. At these conditions, ethanol concentration produced (P), yield (Y
ps) and productivity (Q
p
) were 100 g l−1, 0.42 g g−1 and 1.67 g l−1 h−1 respectively. In fed-batch fermentation, the optimum substrate feeding strategy for ethanol production at the initial sugar
concentration of 24 °Bx was one-time substrate feeding, where P, Y
ps and Q
p
were 120 g l−1, 0.48 g g−1 and 1.11 g l−1 h−1 respectively. These findings suggest that fed-batch fermentation improves the efficiency of ethanol production in terms of
ethanol concentration and product yield. 相似文献
17.
Michelin M Polizeli Mde L Silva DP Ruzene DS Vicente AA Jorge JA Terenzi HF Teixeira JA 《Journal of industrial microbiology & biotechnology》2011,38(12):1979-1984
Fungi producing high xylanase levels have attracted considerable attention because of their potential industrial applications.
Batch cultivations of Aspergillus terricola fungus were evaluated in stirred tank and airlift bioreactors, by using wheat bran particles suspended in the cultivation
medium as substrate for xylanase and β-xylosidase production. In the stirred tank bioreactor, in physical conditions of 30°C,
300 rpm, and aeration of 1 vvm (1 l min−1), with direct inoculation of fungal spores, 7,475 U l−1 xylanase was obtained after 36 h of operation, remaining constant after 24 h. In the absence of air injection in the stirred
tank reactor, limited xylanase production was observed (final concentration 740 U l−1). When the fermentation process was realized in the airlift bioreactor, xylanase production was higher than that observed
in the stirred tank bioreactor, being 9,265 U l−1 at 0.07 vvm (0.4 l min−1) and 12,845 U l−1 at 0.17 vvm (1 l min−1) aeration rate. 相似文献
18.
Anne Usvalampi Kristiina Kiviharju Matti Leisola Antti Nyyssölä 《Journal of industrial microbiology & biotechnology》2009,36(10):1323-1330
Factors affecting the production of the rare sugar l-xylulose from xylitol using resting cells were investigated. An E. coli BPT228 strain that recombinantly expresses a gene for xylitol dehydrogenase was used in the experiments. The ratio of xylitol
to l-xylulose was three times lower in the cytoplasm than in the medium. The effects of pH, temperature, shaking speed, and initial
xylitol concentration on l-xylulose production were investigated in shaking flasks using statistical experimental design methods. The highest production
rates were found at high shaking speed and at high temperature (over 44°C). The optimal pH for both productivity and conversion
was between 7.5 and 8.0, and the optimal xylitol concentration was in the range 250–350 g l−1. A specific productivity of 1.09 ± 0.10 g g−1 h−1 was achieved in a bioreactor. The response surface model based on the data from the shake flask experiments predicted the
operation of the process in a bioreactor with reasonable accuracy. 相似文献
19.
Xiangyuan Deng Song Qin Qun Zhang Peng Jiang Yulin Cui Xiaokun Li 《Plant Cell, Tissue and Organ Culture》2009,97(3):253-261
A human acidic fibroblast growth factor gene, hafgf, was successfully transferred into Laminaria japonica (kelp) gametophytes via microprojectile bombardment using the biolistic PDS-1000/He gene gun. Following phosphinothricin
screening, PCR detection and Southern blot analysis, transgenic L. japonica gametophytes were cultivated in an illuminated bubble-column bioreactor to optimize growth conditions. A maximal final dry
cell density of 1,695 mg l−1 was obtained in a batch culture having an initial dry cell density of 129.75 mg l−1. This was achieved using an aeration rate of 1.08 l air min−1 l−1 culture in a medium containing 1.5 mM inorganic nitrate and 0.15 mM phosphate. In addition, the relationship between different
nitrogen sources and growth of transgenic gametophytes indicated that both urea and sodium nitrate were effective nitrogen
sources for cell growth, while ammonium ions inhibited growth of these gametophytes. 相似文献
20.
A higher Coenzyme Q10 (CoQ10) concentration of 25.04 mg/l was found in airlift bioreactor than the value of 18.11 mg/l obtained in stirred tank under
the aerobic-dark cultivation of Rhodobacter sphaeroides. Aeration rate didn’t show obvious impact to CoQ10 production in airlift bioreactor. The fed-batch operation in airlift bioreactor could increase the biomass concentration
and led to the maximum CoQ10 concentration of 33.91 mg/l measured, but a lower CoQ10 cell content (3.5 mg CoQ10/DCW) was observed in the fed-batch operation as compared to the batch operation. To enhance the CoQ10 content, an aeration-change strategy was proposed in the fed-batch operation of airlift bioreactor. This strategy led to
the maximum CoQ10 concentration of 45.65 mg/l, a 35% increase as compared to the simple fed-batch operation. The results of this study suggested
that a fed-batch operation in airlift bioreactor accompanying aeration-change could be suitable for CoQ10 production. 相似文献