共查询到20条相似文献,搜索用时 15 毫秒
1.
Xiaoyan Liu Jinshun Lv Tong Zhang Yuanfang Deng 《Preparative biochemistry & biotechnology》2013,43(8):825-835
In this study, crude cellulase produced by Trichoderma reesei Rut-30 was used to hydrolyze pretreated straw. After the compositions of the hydrolysate of pretreated straw were optimized, the study showed that natural components of pretreated straw without addition of any other components such as (NH4)2SO4, KH2PO4, or Mg2+ were suitable for citric acid production by Yarrowia lipolytica SWJ-1b, and the optimal ventilatory capacity was 10.0 L/min/L medium. Batch and fed-batch production of citric acid from the hydrolysate of pretreated straw by Yarrowia lipolytica SWJ-1b has been investigated. In the batch cultivation, 25.4 g/L and 26.7 g/L citric acid were yields from glucose and hydrolysate of straw cellulose, respectively, while the cultivation time was 120 hr. In the three-cycle fed-batch cultivation, citric acid (CA) production was increased to 42.4 g/L and the cultivation time was extended to 240 hr. However, iso-citric acid (ICA) yield in fed-batch cultivation (4.0 g/L) was similar to that during the batch cultivation (3.9 g/L), and only 1.6 g/L of reducing sugar was left in the medium at the end of fed-batch cultivation, suggesting that most of the added carbon was used in the cultivation. 相似文献
2.
To develop the easier control method for fed-batch culture of sophorolipid production, we chose rapeseed oil as the most productive oil and compared their productivities in relation to different concentrations of glucose. The optimal concentration of glucose was 30 g/L for sophorolipid production. A fed-batch method was conducted using Candida bombicola ATCC 22214 with rapeseed oil as a secondary substrate. The feeding rate of rapeseed oil was dependent on pH and was calculated by the consumption rate of NaOH and rapeseed oil. The glucose concentration was constantly maintained between 30 and 40 g/L. As a result, we have produced a crude sophorolipid up to 365 g/L for 8 days through a feeding-rate-controlled fed-batch process. 相似文献
3.
Chang HN Kim NJ Kang J Jeong CM Choi JD Fei Q Kim BJ Kwon S Lee SY Kim J 《Bioprocess and biosystems engineering》2011,34(4):419-431
We carried out the first simulation on multi-stage continuous high cell density culture (MSC-HCDC) to show that the MSC-HCDC
can achieve batch/fed-batch product titer with much higher productivity to the fed-batch productivity using published fermentation
kinetics of lactic acid, penicillin and ethanol. The system under consideration consists of n-serially connected continuous stirred-tank reactors (CSTRs) with either hollow fiber cell recycling or cell immobilization
for high cell-density culture. In each CSTR substrate supply and product removal are possible. Penicillin production is severely
limited by glucose metabolite repression that requires multi-CSTR glucose feeding. An 8-stage C-HCDC lactic acid fermentation
resulted in 212.9 g/L of titer and 10.6 g/L/h of productivity, corresponding to 101 and 429% of the comparable lactic acid
fed-batch, respectively. The penicillin production model predicted 149% (0.085 g/L/h) of productivity in 8-stage C-HCDC with
40 g/L of cell density and 289% of productivity (0.165 g/L/h) in 7-stage C-HCDC with 60 g/L of cell density compared with
referring batch cultivations. A 2-stage C-HCDC ethanol experimental run showed 107% titer and 257% productivity of the batch
system having 88.8 g/L of titer and 3.7 g/L/h of productivity. MSC-HCDC can give much higher productivity than batch/fed-batch
system, and yield a several percentage higher titer as well. The productivity ratio of MSC-HCDC over batch/fed-batch system
is given as a multiplication of system dilution rate of MSC-HCDC and cycle time of batch/fed-batch system. We suggest MSC-HCDC
as a new production platform for various fermentation products including monoclonal antibody. 相似文献
4.
Jung Hun Kim Seon-Won Kim Do Quynh Anh Nguyen He Li Sung Bae Kim Yang-Gon Seo Jae-Kyung Yang In-Young Chung Dae Hwan Kim Chang-Joon Kim 《Biotechnology and Bioprocess Engineering》2009,14(5):559-564
Recombinant Escherichia coli engineered to contain the whole mevalonate pathway and foreign genes for β-carotene biosynthesis, was utilized for production
of β-carotene in bioreactor cultures. Optimum culture conditions were established in batch and pH-stat fed-batch cultures
to determine the optimal feeding strategy thereby improving production yield. The specific growth rate and volumetric productivity
in batch cultures at 37°C were 1.7-fold and 2-fold higher, respectively, than those at 28°C. Glycerol was superior to glucose
as a carbon source. Maximum β-carotene production (titer of 663 mg/L and overall volumetric productivity of 24.6 mg/L × h)
resulted from the simultaneous addition of 500 g/L glycerol and 50 g/L yeast extract in pH-stat fed-batch culture. 相似文献
5.
Romel Menacho-Melgar Zhixia Ye Eirik A. Moreb Tian Yang John P. Efromson John S. Decker Ruixin Wang Michael D. Lynch 《Biotechnology and bioengineering》2020,117(9):2715-2727
We report the scalable production of recombinant proteins in Escherichia coli, reliant on tightly controlled autoinduction, triggered by phosphate depletion in the stationary phase. The method, reliant on engineered strains and plasmids, enables improved protein expression across scales. Expression levels using this approach have reached as high as 55% of the total cellular protein. The initial use of the method in instrumented fed-batch fermentations enables cell densities of ∼30 gCDW/L and protein titers up to 8.1 ± 0.7 g/L (∼270 mg/gCDW). The process has also been adapted to an optimized autoinduction media, enabling routine batch production at culture volumes of 20 μl (384-well plates), 100 μl (96-well plates), 20 ml, and 100 ml. In batch cultures, cell densities routinely reach ∼5–7 gCDW/L, offering protein titers above 2 g/L. The methodology has been validated with a set of diverse heterologous proteins and is of general use for the facile optimization of routine protein expression from high throughput screens to fed-batch fermentation. 相似文献
6.
A fed-batch culture strategy for the production of recombinant Escherichia coli cells anchoring surface-displayed transglucosidase for use as a whole-cell biocatalyst for α-arbutin synthesis was developed.
Lactose was used as an inducer of the recombinant protein. In fed-batch cultures, dissolved oxygen was used as the feed indicator
for glucose, thus accumulation of glucose and acetate that affected the cell growth and recombinant protein production was
avoided. Fed-batch fermentation with lactose induction yielded a biomass of 18 g/L, and the cells possessed very high transglucosylation
activity. In the synthesis of α-arbutin by hydroquinone glucosylation, the whole-cell biocatalysts showed a specific activity
of 501 nkat/g cell and produced 21 g/L of arbutin, which corresponded to 76% molar conversion. A sixfold increased productivity
of whole cell biocatalysts was obtained in the fed-batch culture with lactose induction, as compared to batch culture induced
by IPTG. 相似文献
7.
Dan Wu Xiao Wei Yu Tong Chun Wang Rui Wang Yan Xu 《Biotechnology and Bioprocess Engineering》2011,16(2):305-311
Rhizopus lipases have been successfully expressed in Pichia pastors and different fermentation strategies have been investigated. However, there is no sufficient study on the effects of methanol
concentration on the production of Rhizopus lipases in P. pastors. In this study, the lipase from Rhizopus chinensis CCTCC M20102 was expressed under different fed-batch fermentation conditions at methanol concentrations ranging from 0.5
to 3.5 g/L. The lipase activity, stability, and productivities were analyzed. The optimum methanol concentration was 1 g/L,
with the highest lipase activity of 2,130 U/mL, without degradation. Additional information was obtained from the analysis
of methanol consumption and production rates. The results also suggested that the cell concentration at the end of the glycerol
fed-batch phase was very important for cell viability and protease activity. 相似文献
8.
Summary The influence of initial concentration of glucose from 60 to 233 g/l on the production of L-lysine byCorynebacterium sp was studied first in batch culture. The maximum conversion rate into L-lysine was obtained at 165 g/l and the best specific production rate for L-lysine was observed at 65 g/l of glucose. In fed-batch fermentations, better conversion and the specific production rates were obtained. Maintaining of a high glucose concentration in the fed-batch technique allowed a 54% increase of the L-lysine production compared to the batch culture. 相似文献
9.
Qiang Fei Ho Nam Chang Longan Shang Jin-dal-rae Choi 《Biotechnology and Bioprocess Engineering》2011,16(3):482-487
Volatile fatty acids (VFAs), acetic acid, acetates, and ethanol were used as carbon sources for the production of microbial
lipids using Cryptococcus albidus in batch cultures. C. albidus utilized organic acids less than glucose in the production of lipids, resulting in a lipid yield coefficient on VFAs of 0.125
g/g. In a two-stage batch culture, the lipid content increased to 43.8% (w/w) when VFAs were used as the sole carbon source
in the second stage, which was two times higher than that of the batch culture. Furthermore, a 192 h, two-stage fed-batch
cultivation of C. albidus produced a dry cell weight, lipid concentration, and lipid content of 26.4 g/L, 14.5 g/L, and 55.1% (w/w), respectively.
The fed-batch culture model used in this study featured pure VFA solutions, with intermittent feeding, under oxygen-enriched
air supply conditions. This study investigated several alternative carbon sources to reduce the cost of microbial lipids production
and proved the feasibility of using VFAs as the carbon source for the provision of a high lipid content and productivity. 相似文献
10.
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
11.
Yun-Bom Lee Jae-Hyung Jo Min-Hong Kim Hyune-Hwan Lee Hyung-Hwan Hyun 《Biotechnology and Bioprocess Engineering》2013,18(4):770-777
The fed-batch culture system was employed to enhance production of α-ketoglutarate (α-KG) by the strainsof Corynebacterium glutamicum, whose genes encoding the key enzymes responsible for the biosynthesis of L-glutamate from α-KG were deleted. In a shake flask fermentation, C. glutamicum JH110 in which the 3 genes, gdh (encoding glutamate dehydrogenase), gltB (encoding glutamate synthase), and aceA (encoding isocitrate lyase) were disrupted showed the highest production of α-KG (12.4 g/L) compared to the strains JH102 (gdh mutant), JH103 (gltB mutant), and JH107 (gdh gltB double mutant). In the fed-batch cultures using a 5 L-jar fermenter, the strain JH107 produced more α-KG (19.5 g/L), but less glutamic acid (23.3 g/L) than those produced by the parent strain HH109, as well as JH102. The production of α-KG was significantly enhanced and the accumulation of glutamicacid was minimized by the ammonium-limited fed-batch cultures employing C. glutamicum JH107. Further improvement of α-KG production by the strain JH107 was achieved through the ammonium-limited fed-batch culture with the feeding of molasses, and the levels of α-KG and glutamic acid produced were 51.1 and 0.01 g/L, respectively. 相似文献
12.
Ji-Hee Song Jey -R. S. Ventura Chang-Hee Lee Deokjin Jahng 《Biotechnology and Bioprocess Engineering》2011,16(1):42-49
Butyric acid fermentation by Clostridium tyrobutyricum ATCC 25755 using glucose or brown algae as a carbon source was carried out. Initially, different fermentation modes (batch,
fed-batch, and semi-continuous) at pH 6 and 37°C were compared using a model medium containing glucose as a carbon source.
By feeding the whole medium containing 40 ∼ 50 and 30 g/L of glucose into the fed-batch and semi-continuous fermentations,
very similar butyrate yields (0.274 and 0.252 g butyrate/g glucose, respectively) and productivities (0.362 and 0.355 g/L/h,
respectively) were achieved. The highest butyrate concentration was about 50 g/L, which was observed in the fed-batch fermentation
with whole medium feeding. However, semi-continuous fermentation sustained a longer fermentation cycle than the fed-batch
fermentation due to end-product and metabolic waste inhibition. The established conditions were then applied to the fermentation
using brown algae, Laminaria japonica and Undaria pinnatifida, as substrates for butyric acid fermentation. To hydrolyze brown algae, 7.5 ∼ 10% (w/v) dried brown algae powder was suspended
in 1% (w/v) NaOH or 0.5 ∼ 2.5% (w/v) H2SO4 and then autoclaved at 121°C for 30 ∼ 90 min. The resulting butyrate concentration was about 11 g/L, which was produced from
100 g/L of L. japonica autoclaved for 60 min in 1.5% H2SO4 acid solution. 相似文献
13.
The production of water-soluble single-sugar glucuronic acid-based oligosaccharides (WSOS) by a cellulose producing strain
Gluconacetobacter hansenii PJK was studied in a periodically recycled and fed-batch cultivations using glucose/ethanol or glucose only. Fermentations
were carried out in a 2 L jar fermenter equipped with a turbine impeller with 6 flat blades. WSOS were produced constantly
but the bacterial cellulose (BC) production stopped at 48 h of cultivation in a periodically recycled culture using the exhausted
medium supplemented with glucose and ethanol. Tremendous quantities of WSOS were obtained in fed-batch cultivations using
glucose/ethanol (35.6 g/L at 132 h of cultivation) or glucose only (86 g/L after 240 h of cultivation) as the nutritional
source. However, the BC production yield under these nutritional conditions decreased significantly in comparison to previous
studies about the BC production by the same strain. The overall results revealed that G. hansenii is capable of producing enormous quantities of WSOS compared to those reported previously for compounds of a related chemical
nature. Moreover, the WSOS production was found to be dependent on the pH of the culture broth. 相似文献
14.
己二酸是一种具有重要应用价值的二元羧酸,是合成尼龙-66的关键前体。目前,生物法生产己二酸存在生产周期长、生产效率低的问题。本研究选择一株野生型高产琥珀酸菌株大肠杆菌(Escherichia coli) FMME N-2为底盘细胞,首先通过引入逆己二酸降解途径的关键酶,成功构建了可合成0.34 g/L己二酸的E. coli JL00菌株;接着,对合成路径限速酶进行表达优化,使E. coli JL01菌株在摇瓶发酵条件下产量达到0.87 g/L;随后,通过敲除sucD基因、过表达acs基因和突变lpd基因的组合策略平衡己二酸合成前体的供应,优化菌株E. coli JL12己二酸产量进一步提升至1.51 g/L;最后,在5 L发酵罐上对己二酸发酵工艺进行优化。工程菌株经72 h分批补料发酵,己二酸的产量达到22.3 g/L,转化率为0.25 g/g,生产强度为0.31 g/(L·h),具备了一定的应用潜力。本研究可为包括己二酸在内的多种二元羧酸细胞工厂的构建提供理论依据和技术基础。 相似文献
15.
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
16.
This study investigated the effects of DO concentration on DHA fermentation and of DO-stat fed-batch fermentation using a pH control strategy, on 1,3-dihydroxyacetone (DHA) production. The results showed that DO-stat fed-batch fermentation with pH-shift control was the optimal bioprocess for DHA production. DO-stat fed-batch fermentation was carried out at 30% air saturation, and the culture pH was automatically maintained at pH 6.0 during the first 20 h and then shifted to pH 5.0 until the end of the fermentation. An optimal DHA concentration of 175.9 ± 6.7 g/L, with a production yield to glycerol of 0.87 ± 0.04 g/g, was obtained at 72 h of DO-stat fed-batch fermentation at 30°C in a 15 L fermenter. 相似文献
17.
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
18.
Seung-Jin Choi Doo-Hong Park Kyung-Hwan Jung 《Bioprocess and biosystems engineering》2001,24(1):51-58
The long-term process for producing human granulocyte-colony stimulating factor (hG-CSF) was developed using two-stage cyclic fed-batch culture, in which hG-CSF expressing-recombinant Escherichia coli was directed by an L-arabinose promoter system. For the optimization, the preinduction growth rate during the growth stage and the feeding strategy during the production stage were investigated. The maximum harvest volume during the production stage was predicted before long-term cyclic operation. Based on those optimized strategies, the two-stage cyclic fed-batch culture was performed for 12 cycles (86 h). The cell growths in both stages were maintained at 45-50 g/L and 71-77 g/L, respectively. hG-CSF was stably produced at a level of 8-9 g/L and the plasmid stability was maintained at more than 90%. Volumetric productivity by the two-stage cyclic fed-batch culture was 0.643 g/L/h, which was about 280% higher than that of conventional DO-stat fed-batch culture. 相似文献
19.
Phloroglucinol is a valuable chemical which has been successfully produced by metabolically engineered Escherichia coli. However, the low productivity remains a bottleneck for large-scale application and cost-effective production. In the present
work, we cloned the key biosynthetic gene, phlD (a type III polyketide synthase), into a bacterial expression vector to produce phloroglucinol in E. coli and developed different strategies to re-engineer the recombinant strain for robust synthesis of phloroglucinol. Overexpression
of E. coli marA (multiple antibiotic resistance) gene enhanced phloroglucinol resistance and elevated phloroglucinol production to 0.27 g/g
dry cell weight. Augmentation of the intracellular malonyl coenzyme A (malonyl-CoA) level through coordinated expression of
four acetyl-CoA carboxylase (ACCase) subunits increased phloroglucinol production to around 0.27 g/g dry cell weight. Furthermore, the coexpression of ACCase and marA caused another marked improvement in phloroglucinol production 0.45 g/g dry cell weight, that is, 3.3-fold to the original
strain. Under fed-batch conditions, this finally engineered strain accumulated phloroglucinol up to 3.8 g/L in the culture
12 h after induction, corresponding to a volumetric productivity of 0.32 g/L/h. This result was the highest phloroglucinol
production to date and showed promising to make the bioprocess economically feasible. 相似文献
20.
Zhi-Yong Zheng Shan-Jing Yao Xiaobei Zhan Chi Chung Lin 《Biotechnology and Bioprocess Engineering》2009,14(1):52-59
Tryptone has multiple and complex effects on cell physiology and process performance in pulse fed-batch cultivation of recombinant
Escherichia coli. By applying feedback control of dissolved oxygen signal responding to pulse in the feed rate, the production of acetate
was avoided and the optimization of production of recombinant human epidermal growth factor (hEGF) was successfully achieved.
With the addition of an optimum amount of tryptone along with glucose in the pulse fedbatch cultivation of E. coli, the ability of the cell to divide and the stability of the plasmid within the bacteria were improved. Consequently, segregation
of the cells into a viable but non-culturable physiological state was alleviated. Addition of tryptone also enhanced cell
respiration before and after hEGF expression and thus further benefited the production of recombinant hEGF. Excessive addition
of tryptone resulted in low sensitivity of the oscillation of dissolved oxygen signal and poor operability of pulse fed-batch
cultivation as this led to an accumulation of acetate, which weakened the dissolved oxygen signal responses. Consequently,
the production of recombinant protein was considerably reduced. By combining the process performance and the positive effect
of complex media pulse addition on bacterial metabolism, the optimal production conditions of hEGF were successfully determined.
A high cell density of 91 g/L dry cell weight was obtained under these optimal production conditions. Furthermore, a high
level of 0.24 g/L hEGF was attained leading to a 32.6% increase in product yield as compared to the controls. 相似文献