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1.
Ralstonia eutropha NCIMB 11599 and ATCC 17699 were grown, and their productions of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] compared. In flask cultures ofR. eutropha NCIMB 11599, cell concentration, P(3HB-co-4HB) concentration and polymer content decreased considerably with increases in the γ-butyrolactone concentration, and the
4HB fraction was also very low (maximum 1.74 mol%). In fed-batch cultures ofR. eutropha NCIMB 11599, glucose and γ-butyrolactone were fed as the carbon sources, under a phosphate limitation strategy. When glucose
was fed as the sole carbon source, with its concentration controlled using an on-line glucose analyzer, 86% of the P(3HB)
homopolymer was obtained from 201 g/L of cells. In a two-stage fed-batch culture, where the cell concentration was increased
to 104 g/L, with glucose fed in the first step and constant feeding of γ-butyrolactone, at 6 g/h, in the second, final cell
concentration at 67 h was 106 g/L, with a polymer content of 82%, while the 4HB fraction was only 0.7 mol%. When the same
feeding strategy was applied to the fedbatch culture ofR. eutropha ATCC 17699, where the cell concentration was increased to 42 g/L, by feeding fructose in the first step and γ-butyrolactone
(1.5 g/h) in the second, the final cell concentration, polymer content and 4HB fraction at 74 h were 51 g/L, 35% and 32 mol%,
respectively. In summary,R. eutropha ATCC 17699 was better thanR. eutropha NCIMB 11599 in terms of P(3HB-co-4HB) production with various 4HB fractions. 相似文献
2.
Jong-il Choi Sang Yup Lee Kyungsup Shin Woo Gi Lee Si Jae Park Ho Nam Chang Yong Keun Chang 《Biotechnology and Bioprocess Engineering》2002,7(6):371-374
Production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB/V)], by fed-batch culture of recombinantEscherichia coli harboring a plasmid containing theAlcaligenes latus polyhydroxyalkanoate (PHA) biosynthesis genes, was examined in two pilot-scale fermentors with air supply only. In a 30 L
fermentor having aK
La value of 0.11 s−1, the final P(3HB/V) concentration and the P(3HB/V) content obtained were 29.6 g/L and 70.1 wt%, respectively, giving a productivity
of 1.37 g P(3HB/V)/L-h. In a 300 L fermentor having aK
La of 0.03 s−1, the P(3HB/V) concentration and the P(3HB/V) content were 20.4 g/L and 69 wt%, respectively, giving a productivity of 1.06
g P(3HB/V)/L-h. These results suggest that economical production of P(3HB/V) is possible by fed-batch culture of recombinantE. coli in a large-scale fermentor having lowK
La value. 相似文献
3.
Huang TY Duan KJ Huang SY Chen CW 《Journal of industrial microbiology & biotechnology》2006,33(8):701-706
Low-cost raw materials can be used to reduce significantly the production cost of polyhydroxyalkanoates (PHA). In this study, extruded rice bran (ERB) and extruded cornstarch (ECS) were used as carbon sources to produce PHA by an archaea, Haloferax mediterranei, which cannot use native rice bran or cornstarch as a carbon source. By employing pH-stat control strategy to maintain pH at 6.9–7.1 in a 5-liter jar fermentor using ERB:ECS (1:8 g/g) as the major carbon source, we obtained a cell concentration of 140 g/L, PHA concentration of 77.8 g/L and PHA content of 55.6 wt.% in a repeated fed-batch fermentation. In contrast, when ECS was used as the major carbon source, we obtained 62.6 g/L cell concentration, 24.2 g/L PHA concentration and 38.7 wt.% PHA content. Under a hyper-saline condition and with no nitrogen-limitation restriction, the repeated fed-batch process can be sustained a long time for the mass production of PHA. 相似文献
4.
Production of medium-chain-length polyhydroxyalkanoates by high-cell-density cultivation of Pseudomonas putida under phosphorus limitation 总被引:1,自引:0,他引:1
High-cell-density fed-batch cultures of Pseudomonas putida were carried out for the production of medium-chain-length polyhydroxyalkanoates (PHAs) using oleic acid as a carbon source. By employing an optimal feeding strategy without the limitation of any nutrient, a high cell concentration of 173 g/L was achieved, but the PHA concentration and PHA content were only 32.3 g/L and 18.7 wt%, respectively. To increase the PHA concentration and content, phosphorus limitation was applied during fed-bath culture by reducing the initial KH(2)PO(4) concentration. When the initial KH(2)PO(4) concentration was reduced to 4 g/L, cell concentration, PHA concentration, and PHA content obtained in 38 h were 141 g/L, 72. 6 g/L, and 51.4 wt%, respectively, resulting in a high productivity of 1.91 g PHA/L per hour. 相似文献
5.
Preusting H van Houten R Hoefs A van Langenberghe EK Favre-Bulle O Witholt B 《Biotechnology and bioengineering》1993,41(5):550-556
Pseudomonas oleovorans is able to accumulate poly(3-hydroxyalkanoates) (PHAs) under conditions of excess n-alkanes, which serve as sole energy and carbon source, and limitation of an essential nutrient such as ammonium. In this study we aimed at an efficient production of these PHAs by growing P. oleovorans to high cell densities in fed-batch cultures.To examine the efficiency of our reactor system, P. oleovorans was first grown in batch cultures using n-octane as growth substrate and ammonia water for pH regulation to prevent ammonium limiting conditions. When cell growth ceased due to oxygen limiting conditions, a maximum cell density of 27 g .L(-1) dry weight was obtained. When the growth temperature was decreased from the optimal temperature of 30 degrees -18 degrees C, cell growth continued to a final cell density of 35 g . L(-1) due to a lower oxygen demand of the cells at this lower incubation temperature.To quantify mass transfer rates in our reactor system, the volumetric oxygen transfer coefficient (k(L)a) was determined during growth of P. oleovorans on n-octane. Since the stirrer speed and airflow were increased during growth of the organism, the k(L)a also increased, reaching a constant value of 0.49 s(-1) at maximum airflow and stirrer speed of 2 L . min(-1) and 2500 rpm, respectively. This k(L)a value suggests that oxygen transfer is very efficient in our stirred tank reactor.Using these conditions of high oxygen transfer rates, PHA production by P. oleovorans in fed-batch cultures was studied. The cells were first grown batchwise to a density of 6 g . L(-1), after which a nutrient feed, consisting of (NH(4))(2)SO(4) and MgSO(4), was started. The limiting nutrient ammonium was added at a constant rate of 0.23 g NH(4) (+) per hour, and when after 38 h the feed was stopped, a biomass concentration of 37.1 g . L(-1) was obtained. The Cellular PHA content was 33% (w/w), which is equal to a final PHA yield of 12.1 g . L(-1) and an overall PHA productivity of 0.25 g PHA produced per liter medium per hour. (c) 1993 John Wiley & Sons, Inc. 相似文献
6.
Hee Wook Ryu Kyung Suk Cho Philip R. Goodrich Chang-Ho Park 《Biotechnology and Bioprocess Engineering》2008,13(6):651-658
This study examined the effect of adding glucose, yeast extract, and inorganic salts to swine wastewater (SWW) in a batch
culture on the production of a biodegradable plastic, polyhydroxyalkanoate (PHA). A bacterial strain, Azotobacter vinelandii UWD, was used to produce PHA without limiting the non-carbon nutrients. The addition of glucose (30 g/L) to the SWW medium
increased the level of cell growth (4.4∼7.0 times) and PHA production (3.8∼8.5 times) depending upon the dilution of SWW.
A 50% dilution of SWW was found to be optimal considering the dry cell weight (9.40 g/L), PHA content (58 wt%), and hydroxyvalerate
(HV) mol fraction in the PHA (4.3 mol%). A 75% SWW medium was more advantageous for producing PHA with a higher HV fraction
(7.1 mol%) at the expense of losing 22% of PHA production. The undiluted SWW medium produced less than one third of the PHA
compared with the 50% SWW medium, but the HV fraction was the highest (10.8 mol%). Regarding the effect of the glucose concentration,
at 20 g/L glucose, the dry cell weight and level of PHA production increased to 9.34 g/L (0.63 g PHA/g dry cell weight) and
5.90 g/L, respectively. At 50 g/L glucose, there was no significant increase in PHA production. For the glucose-supplemented
(30 g/L) 50% SWW medium, the addition of a nitrogen source (1 g/L of yeast extract) did not increase the level of cell growth
or PHA production because the C:N ratio (23:1) was already close to the optimal value (22:1). Better aeration increased the
productivity of PHA. External nitrogen supplements (1 g/L of yeast extract) and other essential mineral salts was not necessary
for bacterial growth because they were contained in the SWW. These results suggest that SWW is an excellent feedstock for
producing larger amounts of the value-added material, PHA, if it is combined with carbohydrate-rich organic waste. 相似文献
7.
Genta Kobayashi Kuniaki Tanaka Hirokazu Itoh Takeharu Tsuge Kenji Sonomoto Ayaaki Ishizaki 《Biotechnology letters》2000,22(13):1067-1069
The feeding of propionic acid for production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] by Alcaligenes eutrophus ATCC17697 was optimized using a fed-batch culture system. The concentration of propionic acid was maintained at 3 g l–1 as growth was inhibited by propionic acid in the broth. A pH-stat substrate feeding system was used in which propionic acid was fed automatically to maintain a pH of the culture broth at 7.0. By feeding a substrate solution containing 20% (w/v) propionic acid, 4.9% (w/v) ammonia water [at a molar ratio of carbon to nitrogen (C/N molar ratio) of 10] in cell growth phase, the concentration of propionic acid in the broth was maintained at 3 g l–1 giving a specific growth rate of 0.4 h–1. To promote P(3HB-co-3HV) production, two stage fed-batch culture which consisted of the stage for the cell growth and the stage for the P(3HB-co-3HV) accumulation was carried out. When the substrate solution whose C/N molar ratio was 50 was fed in P(3HB-co-3HV) accumulation phase, the cell concentration and the P(3HB-co-3HV) content in the cells reached 64 g l–1 and 58% (w/w) in 55.5 h, respectively. 相似文献
8.
A new fermentation strategy using cell recycle membrane system was developed for the efficient production of poly(3-hydroxybutyrate) (PHB) from whey by recombinant Escherichia coli strain CGSC 4401 harboring the Alcaligenes latus polyhydroxyalkanoate (PHA) biosynthesis genes. By cell recycle, fed-batch cultivation employing an external membrane module, the working volume of fermentation could be constantly maintained at 2.3 l. The final cell concentration, PHB concentration and PHB content of 194 g l–1, 168 g l–1 and 87%, respectively, were obtained in 36.5 h by the pH-stat cell recycle fed-batch culture using whey solution concentrated to contain 280 g lactose l–1 as a feeding solution, resulting in a high productivity of 4.6 g PHB l–1 h–1. 相似文献
9.
Kim BS 《Enzyme and microbial technology》2000,27(10):774-777
Two inexpensive substrates, starch and whey were used to produce poly(3-hydroxybutyrate) (PHB) in fed-batch cultures of Azotobacter chroococcum and recombinant Escherichia coli, respectively. Oxygen limitation increased PHB contents in both fermentations. In fed-batch culture of A. chroococcum, cell concentration of 54 g l−1 with 46% PHB was obtained with oxygen limitation, whereas 71 g l−1 of cell with 20% PHB was obtained without oxygen limitation. The timing of PHB biosynthesis in recombinant E. coli was controlled using the agitation speed of a stirred tank fermentor. A PHB content of 80% could be obtained with oxygen limitation by increasing the agitation speed up to only 500 rpm. 相似文献
10.
High-yield production of polyhydroxyalkanoates (PHAs) by Ralstonia eutropha KCTC 2662 was investigated using soybean oil and γ-butyrolactone as carbon sources. In flask culture, it was shown that R. eutropha KCTC 2662 accumulated PHAs during the growth phase. The optimum carbon to nitrogen ratio (C/N ratio) giving the highest cell and PHA yield was 20 g-soybean oil/g-(NH(4))(2)SO(4). The 4-hydroxybutyrate (4HB) fraction in the copolymer was not strongly affected by the C/N ratio. In a 2.5-L fermentor, a homopolymer of poly(3-hydroxybutyrate) [P(3HB)] was produced from soybean oil as the sole carbon source by batch and fed-batch cultures of R. eutropha with dry cell weights of 15-32 g/L, PHA contents of 78-83 wt% and yields of 0.80-0.82 g-PHA/g-soybean oil used. By co-feeding soybean oil and γ-butyrolactone as carbon sources, a copolymer of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] could be produced with dry cell weights of 10-21 g/L, yields of 0.45-0.56 g-PHA/g-soybean oil used (0.39-0.50g-PHA/g-carbon sources used) and 4HB fractions of 6-10 mol%. Higher supplementation of γ-butyrolactone increased the 4HB fraction in the copolymer, but decreased cell and PHA yield. 相似文献
11.
Ahleum Chung Qian Liu Shao-Ping Ouyang Qiong Wu Guo-Qiang Chen 《Applied microbiology and biotechnology》2009,83(3):513-519
To produce extracellular chiral 3-hydroxyacyl acids (3HA) by fermentation, a novel pathway was constructed by expressing tesB gene encoding thioesterase II into Pseudomonas putida KTOY01, which was a polyhydroxyalkanoate (PHA) synthesis operon knockout mutant. 3HA mixtures of 0.35 g/l consisting of 3-hydroxyhexanoate,
3-hydroxyoctanoate, 3-hydroxydecanoate, and 3-hydroxydodecanoate (3HDD) were produced in shake-flask study using dodecanoate
as a sole carbon source. Additional knockout of fadB and fadA genes encoding 3-ketoacyl-CoA thiolase and 3-hydroxyacyl-CoA dehydrogenase in P. putida KTOY01 led to the weakening of the β-oxidation pathway. The fadBA and PHA synthesis operon knockout mutant P. putida KTOY07 expressing tesB gene produced 2.44 g/l 3HA, significantly more than that of the β-oxidation intact mutant. The 3HA mixture contained 90 mol%
3HDD as a dominant component. A fed-batch fermentation process carried out in a 6-l automatic fermentor produced 7.27 g/l
extracellular 3HA containing 96 mol% fraction of 3HDD after 28 h of growth. For the first time, it became possible to produce
3HDD-dominant 3HA monomers.
Ahleum Chung and Qian Liu contributed equally to this paper. 相似文献
12.
《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
13.
Poly(3-hydroxybutyrate) (PHB) was produced by fed-batch cultures of Ralstonia eutropha with phosphate limitation under different glucose concentrations. When glucose was kept at 2.5 g l–1, cell growth and PHB synthesis were limited due to the shortage of carbon source but a higher PHB content occurred in the cell-growth stage. This shows that a low glucose concentration is favorable for PHB accumulation in R. eutropha. PHB obtained with glucose at 9 g l–1 is 1.6 times that obtained with 40 g l–1. When glucose was in the range of 9 to 40 g l–1, PHB concentration and productivity decreased significantly with the increase of glucose concentration. The highest PHB productivity was obtained with glucose at 9 g l–1. 相似文献
14.
Longan Shang Dai Di Fan Moon Il Kim Jin-dal-rae Choi Ho Nam Chang 《Biotechnology and Bioprocess Engineering》2007,12(4):417-423
High cell density culturing has been conducted for the production of poly(3-hydroxybutyrate) fed-batch cultures ofRalstonia eutropha with phosphate limitation. It was found that a high glucose concentration inhibited the synthesis of P(3HB) in the high cell
density culture ofR. eutropha. Although a low glucose concentration can trigger the synthesis of P(3HB) in a manner similar to that of phosphate limitation,
it also limited both the P(3HB) synthesis and the cell growth, and led to a low P(3HB) productivity because glucose is the
sole carbon source in this reaction. An unstructured model was proposed for predicting the cell growth and P(3HB) synthesis
in high cell density cultures ofR. eutropha, where the phosphate concentration played a key role in the accumulation of P(3HB) and in cell growth. Good agreements were
found between the experimental data and model predictions. The results of simulation showed that the final P(3HB) concentration
would decrease more than 25% when the glucose was concentration increased to 40 g/L, and indicated that the optimal glucose
concentration for P(3HB) production by high cell density cultures ofR. eutropha was around 9 g/L. 相似文献
15.
Iszatty Ismail Tana Poorani Gurusamy Hema Ramachandran 《Preparative biochemistry & biotechnology》2017,47(4):388-396
Antibiofilm polymers have the ability to inhibit bacterial biofilm formation, which is known to occur ubiquitously in the environment and pose risks of infection. In this study, production of P(3HB-co-4HB) copolymer and antimicrobial yellow pigment from Cupriavidus sp. USMAHM13 are enhanced through medium optimization. Before the improvement of yellow pigment production, screening for the best additional supplement was performed resulting in high-yield yellow pigmentation using yeast extract with optimum concentration of 2?g/L. Effects of different concentrations of 1,4-butanediol, ammonium acetate, and yeast extract were studied using central composite design. Under optimal conditions, 53?wt% of polyhydroxyalkanoate (PHA) content, 0.35?g/L of pigment concentration, and 5.87?g/L of residual biomass were achieved at 0.56?wt% C of 1,4-butanediol, 1.14?g/L of ammonium acetate, and 2?g/L of yeast extract. Antibiofilm tests revealed that the yellow pigment coated on P(3HB-co-4HB) copolymer had significant effect on the inhibition of bacteria proliferation and colonization from 6?hr onward reaching 100% inhibition by 12?hr, hence effectively inhibiting the biofilm formation. 相似文献
16.
The fermentation kinetics Zymomonas mobilis were studied near zero growth rate in fed-batch cultures and continuous cultures with complete cell recycle. The results show the ethanol enhances that specific substrate conversion rate under these conditions. The maximum achievable ethanol concentration in continuous cultures with cell recycle (66 g/L) was significantly lower than in fed-batch cultures (100 g/L). The results indicate that growth-rate-independent metabolism is not instantaneous and can lag behind steadily increasing ethanol concentrations in fed-batch fermentations. A model is proposed to account for this slow adaptation. 相似文献
17.
Stanislav Obruca Ivana Marova Ondrej Snajdar Ludmila Mravcova Zdenek Svoboda 《Biotechnology letters》2010,32(12):1925-1932
Waste rapeseed oil is a useful substrate for polyhydroxyalkanoates (PHA) production employing Cupriavidus necator H16. In fed-batch mode, we obtained biomass and PHA yields of 138 and 105 g l−1, respectively. Yield coefficient and volumetric productivity were 0.83 g PHA per g oil and 1.46 g l−1 h−1, respectively. Propanol at 1% (v/v) enhanced both PHA and biomass formation significantly and, furthermore, resulted in incorporation
of 3-hydroxyvalerate units into PHA structure. Thus, propanol can be used as an effective precursor of 3-hydroxyvalarete for
production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer. During the fed-batch cultivation, propanol concentration was maintained at 1% which resulted
in 8% content of 3-hydroxyvalerate in copolymer. 相似文献
18.
Yonggang Wang Peng Du Renbao Gan Zhimin Li Qin Ye 《Biotechnology and Bioprocess Engineering》2005,10(2):149-154
Secretion of the expressed heterologous proteins can reduce the stress to the host cells and is beneficial to their recovery
and purification. In this study, fed-batch cultures ofEscherichia coliYK537 (pAET-8) were conducted in a 5-L fermentor for the secretory production of human epidermal growth factor (hEGF) whose
expression, was under the control of alkaline phosphatase promoter. The effects of feeding of glucose and complex nitrogen
sources on hEGF production were investigated. When the fed-batch culture was conducted in a chemically defined medium, the
cell density was 9.68 g/L and the secreted hEGF was 44.7 mg/L in a period of 60 h. When a complex medium was used and glucose
was added in pH-stat mode, the secreted hEGF was improved to 345 mg/L. When the culture was fed with glucose at a constant
specific rate of 0.25 gg−1h−1, hEGF reached 514 mg/L. The effects of adding a solution containing yeast extract and tryptone were further studied. Different
rate of the nitrogen source feeding resulted in different levels of phosphate and acetic acid formation, thus affected hEGF
expression. At the optimal feeding rate, hEGF production achieved 686 mg/L. 相似文献
19.
Microbial oxidation of D-sorbitol tol-sorbose byAcetobacter suboxydans is of commercial importance since it is the only biochemical process in vitamin C synthesis. The main bottleneck in the batch
oxidation of sorbitol to sorbose is that the process is severely inhibited by sorbitol. Suitable fed-batch fermentation designs
can eliminate the inherent substrate inhibition and improve sorbose productivity. Fed-batch sorbose fermentations were conducted
by using two nutrient feeding strategies. For fed-batch fermentation with pulse feeding highly concentrated sorbitol (600
g/L) along with other nutrients were fed intermittently in four pulses of 0.5 liter in response to the increased DO signal.
The fed-batch fermentation was over in 24 h with a sorbose productivity of 13.40 g/L/h and a final sorbose concentration of
320.48 g/L. On the other hand, in fed-batch fermentation with multiple feeds, two pulse feeds of 0.5 liter nutrient medium
containing 600 g/L sorbitol was followed by the addition of 1.5 liter nutrient medium containing 600 g/L sorbitol at a constant
feed rate of 0.36 L/h till the full working capacity of the reactor. The fermentation was completed in 24 h with an enhanced
sorbose productivity of 15.09 g/L/h and a sorbose concentration of 332.60 g/L. The sorbose concentration and productivity
obtained by multiple feeding of nutrients was found to be higher than that obtained by pulse feeding and was therefore a better
strategy for fed-batch sorbose fermentation. 相似文献
20.
Conversion of 3-hydroxypropionate (3HP) from 1,3-propanediol (PDO) was improved by expressing dehydratase gene (dhaT) and aldehyde dehydrogenase gene (aldD) of Pseudomonas putida KT2442 under the promoter of phaCAB operon from Ralstonia eutropha H16. Expression of these genes in Aeromonas hydrophila 4AK4 produced up to 21 g/L 3HP in a fermentation process. To synthesize homopolymer poly(3-hydroxypropionate) (P3HP), and copolymer poly(3-hydroxypropionate-co-3-hydroxybutyrate) (P3HP4HB), dhaT and aldD were expressed in E. coli together with the phaC1 gene encoding polyhydroxyalkanoate (PHA) synthase gene of Ralstonia eutropha, and pcs' gene encoding the ACS domain of the tri-functional propionyl-CoA ligase (PCS) of Chloroflexus aurantiacus. Up to 92 wt% P3HP and 42 wt% P3HP4HB were produced by the recombinant Escherichia coli grown on PDO and a mixture of PDO+1,4-butanediol (BD), respectively. 相似文献