共查询到20条相似文献,搜索用时 78 毫秒
1.
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
2.
Böer E Breuer FS Weniger M Denter S Piontek M Kunze G 《Applied microbiology and biotechnology》2011,92(1):105-114
Tannase (tannin acyl hydrolase, EC 3.1.1.20) hydrolyses the ester and depside bonds of gallotannins and gallic acid esters
and is an important industrial enzyme. In the present study, transgenic Arxula adeninivorans strains were optimised for tannase production. Various plasmids carrying one or two expression modules for constitutive expression
of tannase were constructed. Transformant strains that overexpress the ATAN1 gene from the strong A. adeninivorans TEF1 promoter produce levels of up to 1,642 U L−1 when grown in glucose medium in shake flasks. The effect of fed-batch fermentation on tannase productivity was then investigated
in detail. Under these conditions, a transgenic strain containing one ATAN1 expression module produced 51,900 U of tannase activity per litre after 142 h of fermentation at a dry cell weight of 162 g L−1. The highest yield obtained from a transgenic strain with two ATAN1 expression modules was 31,300 U after 232 h at a dry cell weight of 104 g L−1. Interestingly, the maximum achieved yield coefficients [Y(P/X)] for the two strains were essentially identical. 相似文献
3.
Cyclodextrin glycosyltransferase (CGTase; E.C. 2.4.1.19) is an industrially important enzyme, which is used to produce cyclodextrins
(CDs). In this research, we report the use of experimental factorial design to find the best conditions of pH and temperature
for CGTase production by Bacillus circulans var. alkalophilus. The optimized calculated values for the tested variables were, respectively, pH 9.7 and temperature 36oC, with a CGTase activity of 615 U mL−1. The CGTase production was further studied with the optimized process parameters on submerged cultivations (SC) and solid-state
cultivations (SSC) using soybean industrial fibrous residue (SIFR). The maximum CGTase activity obtained on SC was 1,155 U mL−1 under aerobic conditions. Cell growth and CGTase synthesis in SSC using SIFR as substrate was excellent, with CGTase activity
of 32,776 U g(SIFR) −1. These results strongly support the use of SIFR for CGTase production since it is a non-expensive residue. 相似文献
4.
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
5.
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
6.
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
7.
Yin Liu Yong-Guang Zhang Ru-Bing Zhang Fan Zhang Jianhang Zhu 《Current microbiology》2011,62(1):152-158
Cosubstrates fermentation is such an effective strategy for increasing subject metabolic products that it could be available
and studied in propionic acid production, using glycerol and glucose as carbon resources. The effects of glycerol, glucose,
and their mixtures on the propionic acid production by Propionibacterium acidipropionici CGMCC1.2225 (ATCC4965) were studied, with the aim of improving the efficiency of propionic acid production. The propionic
acid yield from substrate was improved from 0.475 and 0.303 g g−1 with glycerol and glucose alone, respectively, to 0.572 g g−1 with co-fermentation of a glycerol/glucose mixture of 4/1 (mol/mol). The maximal propionic acid and substrate conversion
rate were 21.9 g l−1 and 57.2% (w/w), respectively, both significantly higher than for a sole carbon source. Under optimized conditions of fed-batch
fermentation, the maximal propionic acid yield and substrate conversion efficiency were 29.2 g l−1 and 54.4% (w/w), respectively. These results showed that glycerol/glucose co-fermentation could serve as an excellent alternative
to conventional propionic acid fermentation. 相似文献
8.
Changhua Hu Yi Zou Wenting Zhao 《World journal of microbiology & biotechnology》2009,25(10):1705-1711
Effect of soybean oil on mycelial biomass and pleuromutilin biosynthesis by Pleurotus mutilis-04 was investigated in shake flask culture. The maximum pleuromutilin production and mycelial biomass were 8.32 ± 0.02 g l−1 and 49.10 ± 1.00 g l−1 when 20 g l−1 soybean oil was fed at 24 and 96 h respectively. A repeated fed-batch fermentation strategy with feeding 3 g l−1 soybean oil from 96 to 144 h at 24 h intervals was developed successfully to maintain mycelial growth and provide abundant
fatty acids for pleuromutilin biosynthesis. Compared with glucose as the sole carbon source, soybean oil was obviously beneficial
for the production of pleuromutilin. The results suggested that manipulation of metabolic regulation by soybean oil was an
effective way to enhance the production pleuromutilin. 相似文献
9.
Biosynthesis of guanosine 5′-diphosphate-l-fucose (GDP-l-fucose) requires NADPH as a reducing cofactor. In this study, endogenous NADPH regenerating enzymes such as glucose-6-phosphate
dehydrogenase (G6PDH), isocitrate dehydrogenase (Icd), and NADP+-dependent malate dehydrogenase (MaeB) were overexpressed to increase GDP-l-fucose production in recombinant Escherichia coli. The effects of overexpression of each NADPH regenerating enzyme on GDP-l-fucose production were investigated in a series of batch and fed-batch fermentations. Batch fermentations showed that overexpression
of G6PDH was the most effective for GDP-l-fucose production. However, GDP-l-fucose production was not enhanced by overexpression of G6PDH in the glucose-limited fed-batch fermentation. Hence, a glucose
feeding strategy was optimized to enhance GDP-l-fucose production. Fed-batch fermentation with a pH-stat feeding mode for sufficient supply of glucose significantly enhanced
GDP-l-fucose production compared with glucose-limited fed-batch fermentation. A maximum GDP-l-fucose concentration of 235.2 ± 3.3 mg l−1, corresponding to a 21% enhancement in the GDP-l-fucose production compared with the control strain overexpressing GDP-l-fucose biosynthetic enzymes only, was achieved in the pH-stat fed-batch fermentation of the recombinant E. coli overexpressing G6PDH. It was concluded that sufficient glucose supply and efficient NADPH regeneration are crucial for NADPH-dependent
GDP-l-fucose production in recombinant E. coli. 相似文献
10.
Lei Li Xiaochun Chen Huajing Ren Jiaming Cao Jian Xiong Jianxin Bai Hanjie Ying 《World journal of microbiology & biotechnology》2011,27(10):2379-2385
A glucose utilizing strain, Arthrobacter A302 was used for cyclic adenosine monophosphate (cAMP) production in batch modes. The non-structured model in a 5 l stirred
tank bioreactor for understanding, controlling, and optimizing the fermentation process was proposed using the logistic equation
for microbial growth, the Luedeking-Piret equation for product formation and Luedeking-Piret-like equation for substrate uptake,
respectively. The production of cAMP was a mixed-growth-associated pattern. Based on model prediction, a comparison of calculated
value using the parameters evaluated above with another experimental data in 30 l bioreactor was used to test the model. The
results predicted from the model were in good agreement with the experimental observations in 30 l bioreactor, which demonstrated
that the model might be useful for the development and optimization of production of cAMP in industrial scale. Based on estimated
kinetic parameters, three different fed-batch modes, constant rate and intermittent (once and repeated), were adopted in order
to obtain more cAMP accumulation. Furthermore, the final production of cAMP reached 11.24 g l−1 after 72 h incubation using three stages feeding strategy. In particular, the cAMP productivity (0.156 g l−1 h−1) was successfully improved by 22.83, 11.43 and 9.86%, respectively, compared with the modes of the batch, constant rate fed-batch
and intermittent fed-batch once. 相似文献
11.
Liaoyuan Zhang Jian’an Sun Yingli Hao Jiawen Zhu Ju Chu Dongzhi Wei Yaling Shen 《Journal of industrial microbiology & biotechnology》2010,37(8):857-862
Serrawettin W1 produced by Serratia marcescens is a surface-active exolipid resulting in a lot foam formation during the 2,3-butanediol (2,3-BD) fermentation process. In
order to avoid excessive addition of antifoam agent and microbial contamination, S. marcescens mutants deficient in serrawettin W1 formation were successfully constructed through insertional inactivation of the swrW gene coding for serrawettin W1 synthase. The shake flask and batch experiments suggested that disruption of the swrW gene led to significant reduction of the foam formation and improved 2,3-BD production a little. Ultimately, fed-batch culturing
of the mutant afforded a maximum 2,3-BD concentration of 152 g l−1 with a productivity of 2.67 g l−1 h−1 and a yield of 92.6% at 57 h. 相似文献
12.
Production of Alkaline Protease with <Emphasis Type="Italic">Teredinobacter turnirae</Emphasis> in Controlled Fed-batch Fermentation 总被引:2,自引:0,他引:2
By using our previously optimized media and a fed-batch operation controlled by LabVIEW Software, the key parameter for a
high production of alkaline protease using the marine bacterium, Teredinobacter turnirae, was to maintain a low concentration of C and N-sources ( < 2 g sucrose l−1 and < 0.2 g NH4C l l−1) using an appropriate fed-batch culture system. A maximum protease activity of 8250 U ml−1 was thus achieved. 相似文献
13.
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
14.
Hadeer Lazim Nedra Slama Houda Mankai Insaf Barkallah Ferid Limam 《World journal of microbiology & biotechnology》2010,26(7):1317-1322
Streptomyces rimosus CN08 isolated from Tunisian soil produced 8.6 mg l−1 of oxytetracycline (OTC) under submerged fermentation (SmF). Attempts were made for enhancing OTC production after irradiation-induced
mutagenesis of Streptomyces rimosus CN08 with Co60-γ rays. 125 OTC-producing colonies were obtained after screening on kanamycin containing medium. One mutant called Streptomyces rimosus γ-45 whose OTC production increased 19-fold (165 mg l−1) versus wild-type strain was selected. γ-45 mutant was used for OTC production under solid-state fermentation (SSF). Wheat
bran (WB) was used as solid substrate and process parameters influencing OTC production were optimized. Solid-state fermentation
increased the yield of antibiotic production (257 mg g−1) when compared with submerged fermentation. Ammonium sulphate as additional nitrogen source enhanced OTC level to 298 mg g−1. Interestingly, OTC production by γ-45 mutant was insensitive to phosphate which opens the way to high OTC production even
in medium containing phosphate necessary for optimal mycelia growth. 相似文献
15.
Atlić A Koller M Scherzer D Kutschera C Grillo-Fernandes E Horvat P Chiellini E Braunegg G 《Applied microbiology and biotechnology》2011,91(2):295-304
Poly(hydroxyalkanoates) (PHAs) constitute biodegradable polyesters and are considered among the most promising candidates
to replace common petrochemical plastics in various applications. To date, all commercial processes for PHA production employ
microbial discontinuous fed-batch fermentations. These processes feature drawbacks such as varying product quality and the
inevitable periods of downtime for preparation and post-treatment of the bioreactor equipment. An unprecedented approach to
PHA production was chosen in the presented work using a multistage system consisting of five continuous stirred tank reactors
in series (5-SCR), which can be considered as a process engineering substitute of a continuous tubular plug flow reactor.
The first stage of the reactor cascade is the site of balanced bacterial growth; thereafter, the fermentation broth is continuously
fed from the first into the subsequent reactors, where PHA accumulation takes place under nitrogen-limiting conditions. Cupriavidus necator was used as production strain. The focus of the experimental work was devoted to the development of a PHA production process
characterized by high productivity and high intracellular polymer content. The results of the experimental work with the reactor
cascade demonstrated its potential in terms of volumetric and specific productivity (1.85 g L−1 h−1 and 0.100 g g−1 h−1, respectively), polymer content (77%, w/w) and polymer properties (M
w = 665 kg/mol, PDI = 2.6). Thus, implementing the technology for 5-SCR production of PHB results in an economically viable
process. The study compares the outcome of the work with literature data from continuous two-stage PHA production and industrial
PHA production in fed-batch mode. 相似文献
16.
Butanol, a four-carbon primary alcohol (C4H10O), is an important industrial chemical and has a good potential to be used as a superior biofuel. Bio-based production of
butanol from renewable feedstock is a promising and sustainable alternative to substitute petroleum-based fuels. Here, we
report the development of a process for butanol production from glycerol, which is abundantly available as a byproduct of
biodiesel production. First, a hyper butanol producing strain of Clostridium pasteurianum was isolated by chemical mutagenesis. The best mutant strain, C. pasteurianum MBEL_GLY2, was able to produce 10.8 g l−1 butanol from 80 g l−1 glycerol as compared to 7.6 g l−1 butanol produced by the parent strain. Next, the process parameters were optimized to maximize butanol production from glycerol.
Under the optimized batch condition, the butanol concentration, yield, and productivity of 17.8 g l−1, 0.30 g g−1, and 0.43 g l−1 h−1 could be achieved. Finally, continuous fermentation of C. pasteurianum MBEL_GLY2 with cell recycling was carried out using glycerol as a major carbon source at several different dilution rates.
The continuous fermentation was run for 710 h without strain degeneration. The acetone–butanol–ethanol productivity and the
butanol productivity of 8.3 and 7.8 g l−1 h−1, respectively, could be achieved at the dilution rate of 0.9 h−1. This study reports continuous production of butanol with reduced byproducts formation from glycerol using C. pasteurianum, and thus could help design a bioprocess for the improved production of butanol. 相似文献
17.
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
18.
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
19.
Kim JH Han KC Koh YH Ryu YW Seo JH 《Journal of industrial microbiology & biotechnology》2002,29(1):16-19
Xylitol, a functional sweetener, was produced from xylose by biological conversion using Candida tropicalis ATCC 13803. Based on a two-substrate fermentation using glucose for cell growth and xylose for xylitol production, fed-batch
fermentations were undertaken to increase the final xylitol concentration. The effects of xylose and xylitol on xylitol production
rate were studied to determine the optimum concentrations for fed-batch fermentation. Xylose concentration in the medium (100
g l−1) and less than 200 g l−1 total xylose plus xylitol concentration were determined as optimum for maximum xylitol production rate and xylitol yield.
Increasing the concentrations of xylose and xylitol decreased the rate and yield of xylitol production and the specific cell
growth rate, probably because of an increase in osmotic stress that would interfere with xylose transport, xylitol flux to
secretion to cell metabolism. The feeding rate of xylose solution during the fed-batch mode of operation was determined by
using the mass balance equations and kinetic parameters involved in the equations in order to increase final xylitol concentration
without affecting xylitol and productivity. The optimized fed-batch fermentation resulted in 187 g l−1 xylitol concentration, 0.75 g xylitol g xylose−1 xylitol yield and 3.9 g xylitol l−1 h−1 volumetric productivity. Journal of Industrial Microbiology & Biotechnology (2002) 29, 16–19 doi:10.1038/sj.jim.7000257
Received 15 October 2001/ Accepted in revised form 30 March 2002 相似文献
20.
John Chi-Wei Lan Tau Chuan Ling Grant Hamilton Andrew Lyddiatt 《Biotechnology and Bioprocess Engineering》2006,11(5):425-431
The development of fermentation conditions for the production of C595 diabody fragment (dbFv) inE. coli HB2151 clone has been explored. Investigations were carried out to study the effect of carbon supplements over the expression
period, the comparison of C595 dbfv production in synthetic and complex media, the influence of acetic acid upon antibody
production, and comparison of one-stage and two-stage processes operated at batch or fed-batch modes in bioreactor. Yeast
extract supplied during expression yielded more antibody fragment than any other carbon supply. The synthetic medium presented
higher specific productivity (0.066 mg dbFv g−1 dry cell weight) when compared to the complex medium (0.044 mg dbFv g−1 DCW). The comparison of fermentation strategies demonstrated that (1) one-stage fed-batch fermentation performed higher C595
dbFv production than that operated in batch mode which was significantly affected by acetate concentration; (2) a two-stage
batch operation could enhance C595 dbFv production. It was found that a concentration of 12.3 mg L−1 broth of C595 dbFv and a cell concentration of 10.8 g L−1 broth were achieved at the end of two-stage operation in 5-L fermentation. 相似文献