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1.
Ni-Ni Guo Zong-Ming Zheng Yu-Lin Mai Hong-Juan Liu De-Hua Liu 《Applied microbiology and biotechnology》2010,86(2):701-707
The filtration in 1,3-propanediol (1,3-PD) downstream process is influenced by the large amounts of capsular polysaccharides
(CPS) produced by Klebsiella pneumoniae CGMCC 1.6366. The morphological and fermentation properties were investigated with the CPS-deficient mutant K. pneumoniae CGMCC 1.6366 CPS. Similar biomass was obtained with CGMCC 1.6366, and the mutant strain in batch cultures indicating the
cell growth was slightly inhibited by CPS defection. The viscosity of fermentation broth by mutant strain decreased by 27.45%.
The flux with ceramic membrane filter was enhanced from 168.12 to 303.6 l h−1 m−2, exhibiting the great importance for downstream processing of 1,3-PD fermentation. The products spectrum of mutant isolate
changed remarkably regarding to the concentration of fermentation products. The synthesis of important 1,3-PD and 2,3-butanediol
was enhanced from 9.73 and 4.06 g l−1 to 10.37 and 4.77 g l−1 in batch cultures. The noncapsuled K. pneumoniae provided higher 1,3-PD yield of 0.54 mol mol−1 than that of encapsuled wild parent in batch cultures. The fed-batch fermentation of mutant strain resulted in 1,3-PD concentration,
yield, and productivity of 78.13 g l−1, 0.53 mol mol−1, and 1.95 g l−1 h−1, respectively. 相似文献
2.
1,3-Propanediol (1,3-PD) can be produced from glycerol by Klebsiella pneumoniae under micro-aerobic conditions. Recently, this fed-batch fermentation process has been successfully scaled up to 1 m3. The final 1,3-PD concentration, molar yield and volumetric productivity of 72 g l−1, 57% and 2.1 g l−1 h−1, respectively, are close to those of 75 g l−1, 61%, and 2.2 g l−1 h−1 under anaerobic conditions. This process would be suitable for the production of 1,3-PD on a large scale. 相似文献
3.
Klebsiella oxytoca M5al is an excellent 1,3-propanediol (1,3-PD) producer, but too much lactic acid yielded greatly lessened the fermentation
efficiency for 1,3-PD. To counteract the disadvantage, four lactate deficient mutants were obtained by knocking out the ldhA gene of lactate dehydrogenase (LDH) of K. oxytoca M5al. The LDH activities of the four mutants were from 3.85 to 6.92% of the parental strain. The fed-batch fermentation of
1,3-PD by mutant LDH3, whose LDH activity is the lowest, was studied. The results showed that higher 1,3-PD concentration,
productivity, and molar conversion rate from glycerol to 1,3-PD can be gained than those of the wild type strain and no lactic
acid is produced under both anaerobic and microaerobic conditions. Sucrose fed during the fermentation increased the conversion
and sucrose added at the beginning increased the productivity. In fed-batch fermentation with sucrose as cosubstrate under
microaerobic conditions, the 1,3-PD concentration, conversion, and productivity were improved significantly to 83.56 g l−1, 0.62 mol mol−1, and 1.61 g l−1 h−1, respectively. Furthermore, 60.11 g l−1 2,3-butanediol was also formed as major byproduct in the broth. 相似文献
4.
Microbial production of 1,3-propanediol by Klebsiella pneumoniae using crude glycerol from biodiesel preparations 总被引:3,自引:0,他引:3
1,3-Propanediol (1,3-PD) was produced by Klebsiella pneumoniae using crude glycerol obtained from biodiesel production. The 1,3-PD concentration of 51.3 g/l−1 on crude glycerol from alkali-catalyzed methanolysis of soybean oil was comparable to that of 53 g/l−1 on crude glycerol derived from a lipase-catalyzed process. The productivities of 1.7 g l−1 h−1 on crude glycerol were comparable to that of 2 g l−1 h−1 on pure glycerol. It could be concluded that the crude glycerol could be directly converted to 1,3-PD without any prior purification. 相似文献
5.
Yuanhao Wang Hu Teng Zhilong Xiu 《Journal of industrial microbiology & biotechnology》2011,38(6):705-715
The microbial production of 1,3-propaneidol (1,3-PD) by Klebsiella pneumoniae in continuous fermentation was investigated under low, medium and high glycerol concentrations in the absence and presence
of oxygen. The production of 1,3-PD increased with increasing glycerol concentrations, reaching a maximum (266 mmol l−1) under high glycerol concentration (760 mmol l−1) with air sparging at 0.04 vvm. The yield of 1,3-PD, however, decreased gradually with increasing glycerol concentrations,
with the highest yield (0.52 mol mol−1) obtained for low glycerol concentration (270 mmol l−1) under anaerobic condition. Enzyme activity assays showed that the specific activity of glycerol dehydratase was highest
(0.04 U mg−1) for culture sparged with 0.04 vvm air under high glycerol concentration. The specific activities of glycerol dehydrogenase
and 1,3-propanediol oxidoreductase were also improved for all glycerol concentrations and in the presence of oxygen, implying
that the dha operon was not repressed under microaerobic conditions. Analysis of metabolic fluxes showed that more carbon flux was shifted
to the oxidative pathway with increasing glycerol concentrations, resulting in a reduced flux to 1,3-PD formation. However,
the increases in carbon fluxes were not evenly distributed among the oxidative branches of the pathway. Furthermore, ethanol
and acetic acid levels were slightly increased whereas 2,3-butanediol and lactic levels were greatly enhanced. 相似文献
6.
Lian Hua Luo Jeong-Woo Seo Baek-Rock Oh Pil-Soo Seo Sun-Yeon Heo Won-Kyung Hong Dae-Hyuk Kim Chul Ho Kim 《Journal of industrial microbiology & biotechnology》2011,38(8):991-999
Previously, we constructed a glycerol oxidative pathway-deficient mutant strain of Klebsiella pneumoniae by inactivation of glycerol dehydrogenase (dhaD) to eliminate by-product synthesis during production of 1,3-propanediol (1,3-PD) from glycerol. Although by-product formation
was successfully blocked in the resultant strain, the yield of 1,3-PD was not enhanced, probably because dhaD disruption resulted in insufficient regeneration of the cofactor NADH essential for the activity of 1,3-PD oxidoreductase
(DhaT). To improve cofactor regeneration, in the present study we overexpressed an NAD+-dependent aldehyde dehydrogenase in the recombinant strain. To this end, an aldehyde dehydrogenase AldHk homologous to E. coli AldH but with NAD+-dependent propionaldehyde dehydrogenase activity was identified in K. pneumoniae. Functional analysis revealed that the substrate specificity of AldHk embraced various aldehydes including propionaldehyde,
and that NAD+ was preferred over NADP+ as a cofactor. Overexpression of AldHk in the glycerol oxidative pathway-deficient mutant AK/pVOTHk resulted in a 3.6-fold
increase (0.57 g l−1 to 2.07 g l−1) in the production of 3-hydroxypropionic acid (3-HP), and a 1.1-fold enhancement (8.43 g l−1 to 9.65 g l−1) of 1,3-PD synthesis, when glycerol was provided as the carbon source, compared to the levels synthesized by the control
strain (AK/pVOT). Batch fermentation using AK/pVOTHk showed a significant increase (to 70%, w/w) in conversion of glycerol
to the reductive metabolites, 1,3-PD and 3-HP, with no production of by-products except acetate. 相似文献
7.
Guggulsterone, a hypolipidemic natural agent, is produced in resin canals of the plant Commiphora wightii. In this study, the stimulatory effects of growth retardants [ALAR (N,N-dimethylaminosuccinamic acid) and CCC (chlormequat chloride)] and fungal elicitor on guggulsterone accumulation in cell cultures
of C. wightii are reported. CCC at 1 mg l−1 enhanced guggulsterone content (~123 μg l−1) when added on the fifth day after inoculation, while ALAR at 2.5 mg l−1 increased guggulsterone content (~116 μg l−1) when added on the tenth day. In a two-stage fed-batch process, combined treatment with fungal elicitor and growth retardant
caused a significant increase (~353 μg l−1) in guggulsterone content in cell cultures after 17 days of growth. This represents an approximately fivefold increase over
the guggulsterone contents in initial cultures of this plant. 相似文献
8.
Microbial fed-batch production of 1,3-propanediol by Klebsiella pneumoniae under micro-aerobic conditions 总被引:6,自引:0,他引:6
The microbial production of 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae under micro-aerobic conditions was investigated in this study. The experimental results of batch fermentation showed that the final concentration and yield of 1,3-PD on glycerol under micro-aerobic conditions approached values achieved under anaerobic conditions. However, less ethanol was produced under microaerobic than anaerobic conditions at the end of fermentation. The batch micro-aerobic fermentation time was markedly shorter than that of anaerobic fermentation. This led to an increment of productivity of 1,3-PD. For instance, the concentration, molar yield, and productivity of 1,3-PD of batch micro-aerobic fermentation by K. pneumoniae DSM 2026 were 17.65 g/l, 56.13%, and 2.94 g l–1 h–1, respectively, with a fermentation time of 6 h and an initial glycerol concentration of 40 g/l. Compared with DSM 2026, the microbial growth of K. pneumoniae AS 1.1736 was slow and the concentration of 1,3-PD was low under the same conditions. Furthermore, the microbial growth in fed-batch fermentation by K. pneumoniae DSM 2026 was faster under micro-aerobic than anaerobic conditions. The concentration, molar yield, and productivity of 1,3-PD in fed-batch fermentation under micro-aerobic conditions were 59.50 g/l, 51.75%, and 1.57 g l–1 h–1, respectively. The volumetric productivity of 1,3-PD under microaerobic conditions was almost twice that of anaerobic fed-batch fermentation, at 1.57 and 0.80 g l–1 h–1, respectively. 相似文献
9.
Xuedong Xue Wei Li Zhimin Li Yuelan Xia Qin Ye 《Journal of industrial microbiology & biotechnology》2010,37(7):681-687
In fed-batch culture of Klebsiella pneumoniae, 1,3-propanediol production was growth associated, while the by-products, including lactic acid and ethanol, increased sharply
as the cells grew slowly. When the fed-batch culture was supplied with a mixture of organic acids including citrate, fumarate
and succinate, cell growth and 1,3-propanediol production increased significantly, whereas the by-products, especially lactic
acid and ethanol, decreased sharply. High concentrations of PDO and acetate inhibited cell growth and PDO production. To improve
the PDO production, repeated fed-batch culture with addition of the organic acid mixture was performed in a 5-l reactor. The
fed-batch culture was repeated five times, and the 1,3-propanediol yield and concentration reached above 0.61 mol mol−1 and 66 g l−1, respectively, in 20 h for each cycle. Furthermore, the PDO productivity reached above 3.30 g l−1 h−1 in each cycle, which was much higher than that of the original fed-batch culture. 相似文献
10.
Broth containing 152 g glycerol l−1 from Candida krusei culture was converted to 1,3-propanediol by Klebsiella pneumoniae. Residual glucose in the broth promoted growth of K. pneumoniae while acetate was inhibitory. After desalination treatment of glycerol broth by electrodialysis, the acetate in the broth was removed. A fed-batch culture with electrodialytically pretreated broth as␣substrate was developed giving 53 g 1,3- propanediol l−1 with a yield of 0.41 g g−1 glycerol and a productivity of 0.94 g l−1 h−1. 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.
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
13.
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
14.
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
15.
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
16.
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
17.
《Applied microbiology and biotechnology》2008,78(6):1089-1343
Poly(3-hydroxybutyrate) (PHB) synthesis was analyzed under microaerobic conditions in a recombinant Escherichia coli arcA mutant using glycerol as the main carbon source. The effect of several additives was assessed in a semi-synthetic medium
by the ‘one-factor-at-a-time’ technique. Casein amino acids (CAS) concentration was an important factor influencing both growth
and PHB accumulation. Three factors exerting a statistically significant influence on PHB synthesis were selected by using
a Plackett–Burman screening design [glycerol, CAS, and initial cell dry weight (CDW) concentrations] and then optimized through
a Box–Wilson design. Under such optimized conditions (22.02 g l−1 glycerol, 1.78 g l−1 CAS, and 1.83 g l−1 inoculum) microaerobic batch cultures gave rise to 8.37 g l−1 CDW and 3.52 g l−1 PHB in 48 h (PHB content of 42%) in a benchtop bioreactor. Further improvements in microaerobic PHB accumulation were obtained
in fed-batch cultures, in which glycerol was added to maintain its concentration above 5 g l−1. After 60 h, CDW and PHB concentration reached 21.17 and 10.81 g l−1, respectively, which results in a PHB content of 51%. Microaerobic fed-batch cultures allowed a 2.57-fold increase in volumetric
productivity when compared with batch cultures.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
An erratum to this article can be found at 相似文献
18.
Candida cylindracea NRRL Y-17506 was grown to produce extracellular lipase from oleic acid as a carbon source. Through flask cultures, it was found that the optimum initial oleic acid concentration for cell growth was 20 g l−1. However, high initial concentrations of oleic acid up to 50 g l−1 were not inhibitory. The highest extracellular lipase activity obtained in flask culture was 3.0 U ml−1 after 48 h with 5 g l−1 of initial oleic acid concentration. Fed-batch cultures (intermittent and stepwise feeding) were carried out to improve cell concentration and lipase activity. For the intermittent feeding fed-batch culture, the final cell concentration was 52 g l−1 and the extracellular lipase activity was 6.3 U ml−1 at 138.5 h. Stepwise feeding fed-batch cultures were carried out to simulate an exponential feeding and to investigate the effects of specific growth rate (0.02, 0.04 and 0.08 h−1) on cell growth and lipase production. The highest final cell concentration obtained was 90 g l−1 when the set point of specific growth rate (μset) was 0.02 h−1. High specific growth rate (0.04 and 0.08 h−1) decreased extracellular lipase production in the later part of fed-batch cultures due to build-up of the oleic acid oversupplied. The highest extracellular lipase activity was 23.7 U ml−1 when μset was 0.02 h−1, while the highest lipase productivity was 0.31 U ml−1 h−1 at μset of 0.08 h−1. 相似文献
19.
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
20.
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