• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.5
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• pp.340-344
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• 2000

Microbial oxidation of D-sorbitol to L-sorbose by Acetobacter 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 sorbitor (600g/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 24h with a sorbose productivity of 13.40g/L/h and a final sorbose concentration of 320.48g/L. On the other hand, in fed-batch fermentation with multiple feeds, two pulse feeds of 0.5 liter nutrient medium containing 600g/L sorbitol was followed by the addition of 1.5 liter nutrient medium containing 600g/L sorbitol at a constant feed rate of 0.36L/h till the full working capacity of the reactor. The fermentation was completed in 24h with an enhanced sorbose productivity of 15.09g/L/h and a sorbose concentration of 332.60g/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.

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1695-1702
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• 2009

An animal-component-free and chemically defined fed-batch process for GS-engineered cell lines producing recombinant antibodies has been developed. The fed-batch process relied on supplying sufficient nutrients to match their consumption, simultaneously minimizing the accumulation of by-products (lactate and osmolality). The proportionalities of nutritional consumption were determined by direct analysis. The robust, metabolically responsive feeding strategy was based on the offline measurement of glucose. The fed-batch process was shown to perform equivalently in GS-CHO and GS-NS0 cultures. Compared with batch cultures, the fed-batch technology generated the greater increase in cell yields (5-fold) and final antibody concentrations (4-8-fold). The majority of the increase in final antibody concentration was a function of the increased cell density and the prolonged culture time. This generic and high-yielding fed-batch process would shorten development time, and ensure process stability, thereby facilitating the manufacture of therapeutic antibodies by GS-engineered cell lines.

• KSBB Journal
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• v.24 no.4
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• pp.377-382
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• 2009

The culture condition of growing Chlorella minutissima was optimized to produce biodiesel for fed-batch cultivation. First, under heterotrophic cultivation, the optimum level of glucose was determined to be 10 g/L for 20 days. After, three cultivation conditions were operated: autotrophic, heterotrophic, and mixotrophic growth. The lipid level and the maximum cell concentration from the fed-batch heterotrophic process were 32.0 (%, v/v) and 15.0 (g-dry wt./L) in 20 L flask, respectively. In addition, since the relatively constant specific lipid production rate was observed as 0.040 (% lipid/g-dry wt./day) at the latter period of cultivation time, the fed-batch process could maintain continuous lipid production. Fed-batch process is higher than those values from the batch process. The lipids from the fed-batch process contained over 38% of $C_{18}$, known as the suitable composition for the biodiesel application. For mixotrophic and heterotrophic growth under fed-batch condition, glucose was proved to be an appropriate carbon source for a large scale outdoor cultivation. For fed-batch cultivation, the feeding rate of seawater medium containing glucose was decided to be 0.5 L/day. The mixotrophic cultivation maintained maximum cell concentration of 24 (g-dry wt./L) and the lipid level of 43 (%, w/w). The lipid composition from this process was also proved to be suitable for the biodiesel production. The fatty acids from the mixotrophic growth contains 18% of $C_{17}$ and 49% of $C_{18}$, implying It also tells that C. minutissima is a suitable resource of biodiesel. Especially, the mixotrophic cultivation with fed-batch process might be useful for the large scale cultivation for the biodiesel production.

• Journal of Microbiology and Biotechnology
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• v.11 no.5
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• pp.887-889
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• 2001

The gene encoding yeast pro-carboxypeptidase Y (pro-CPY) has been cloned and expressed in Escherichia coli. Most of the expressed pro-CPY was accumulated as cytoplasmic insoluble aggregates. In our previous study, active CPY was obtained by renaturation of entirely denatured pro-CPY followed by in vitro proteolytic processing with proteinase K along with the activation process. The same refolding process was performed to produce an active CPY from pro-CPY inclusion bodies with renaturation buffers containing proteinase K at different concentrations. The refolding efficiency decreased from $25\%\;to\;2\%$ in the renaturation buffers containing proteinase K at concentrations of $60{\mu}g/ml\;and\;0.6{\mu}g/mi$, respectively. In an attempt to increase the refolding efficiency with a lesser amount of proteinase K, a novel fed-batch refolding process was developed. In a fed-batch refolding, 99 ml of the renaturation buffer containing pro-CPY was gradually added into 1 ml of the renaturation buffer containing $60{\mu}g/ml$ of proteinase K to give a final proteinase K concentration of $0.6{\mu}g/ml$. The fed-batch refolding process resulted in a refolding efficiency of $18\%$, which corresponded to a 9-fold increase over that ($2\%$) in the batch process.

• Fisheries and Aquatic Sciences
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• v.21 no.10
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• pp.33.1-33.11
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• 2018

As a process for commercial application, production of reducing sugar, antioxidant, and DNA protective compounds from shrimp-shell powder was investigated in a fed-batch biodegradation using Bacillus cereus EW5. The fed-batch biodegradation was operated in a 5-L bioreactor for 96 h according to three times pulse-feeding strategy. On the basis of the equal working volume (3 L), the fed-batch biodegradation showed a better production of the target compounds than the batch biodegradation, with higher cell density and shortened biodegradation period. The maximum values of the target compounds were 0.297 mg/mL of reducing sugar, 92.35% DPPH radical scavenging activity, 98.16% ABTS radical scavenging activity, and 1.55 reducing power at $A_{700}$, which were approximately 12.1, 3.4, 5.2, and 8.4% enhanced, respectively, compared with those obtained from the batch biodegradation. The fed-batch culture supernatant also showed the enhanced DNA damage inhibition activity than the batch culture supernatant. As a result, the fed-batch biodegradation accompanied by high cell density could produce more useful compounds, enabling an increase in the reutilization value of shrimp-shell waste.

• Journal of Microbiology and Biotechnology
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• v.1 no.2
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• pp.111-115
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• 1991

The green alga, Dunaliella salina under fed-batch cultivation produced 51.12 mg of hydrocarbon per liter with maintaining 0.313 (g dry wt/l). About 20% of hydrocarbon production yield based on dry biomass was obtained from both batch and fed-batch processes. Optimum culture conditions of light intensity, pH and salt concentration were obtained as 0.0080 (kJ/$cm^2$/h), 8.0 and 1.4 (g of NaCl/l), respectively by response surface analysis. The production of hydrocarbons in D. salina was closely correlated to cell growth. Fed-batch cultivation produced more hydrocarbons and maintained better cell growth than a batch process.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.312-315
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• 2005

A process for efficient recycle fed-batch culture was carried out to increase cell mass and spore production by Lactic acid bacteria isolated from Kimchi. A large quantity of cell mass obtained by feeding concentration of sugar in recycle fed-batch culture. When the high density of salt was created that the cell mass was come-down. In this study, cultured in different feeding concentration of sugar conditions. Lactic acid bacteria by recycle fed-batch culture was investigated in 2L working volume of fermenter, obtained the maximum cell mass was 15.17g/L.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.972-981
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• 2009

In this paper, a fed-batch cultivation process in recombinant Escherichia coli BL21(DE3) bacteria, for the production of human soluble catechol-O-methyltransferase (hSCOMT), is presented. For the first time, a straightforward model is applied in a recombinant hSCOMT expression system and distinguishes an initial cell growth phase from a protein production phase upon induction. Specifically, the kinetic model predicts biomass, substrate, and product concentrations in the culture over time and was identified from a series of fed-batch experiments designed by testing several feed profiles. The main advantage of this model is that its parameters can be identified more reliably from distinct fed-batch strategies, such as glycerol pulses and exponential followed by constant substrate additions. Interestingly, with the limited amount of data available, the proposed model accomplishes satisfactorily the experimental results obtained for the three state variables, and no exhaustive process knowledge is required. The comparison of the measurement data obtained in a validation experiment with the model predictions showed the great extrapolation capability of the model presented, which could provide new complementary information for the COMT production system.

• KSBB Journal
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• v.6 no.1
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• pp.35-43
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• 1991

The production of poly-$\beta$-hydroxybutyrate(PHB) from methanol by batch and fed-batch cultivations of Methylobacterium sp. GL-10 was studied. PHB accumulation was stimulated by the nutrients deficiency including, NH4+, SO42-, and K+. The nitrogen deficiency was the most critical factor for PHB accumulation. In batch cultivation, the maximum cell concentration and PHB content were 1.86g/l and 0.62g/l, respectively, with 1.0%(v/v) of methanol and 0.5g/1 of ammonium sulfate. The mass doubling time of Methylobacterum sp. GL-10 was in the range of 4-5 hrs. The cell growth and PHB accumulation were severely inhibited at the methanol concentration over than 2% (v/v). To overcome methanol Inhibition, constant feeding and intermittent feedillg fed-batch cultivations were adopted, using C/N molar ratio as a control factor. In constant feeding fed-batch process, cell concentration was increased up to 2.67g/1, and PHB yield was enhanced from 0.33 of batch culture to 0.53. The relatively low cell concentration was caused by methanol accumulated in culture broth at late growth phase. To prevent methanol accumulation and to maximize PHB production, DO-state intermittent fed-batch cultivation was attempted. The cell and PHB concentration was reached up to 4.55g/1 and 1.80g/1, respectively. It was possible to maintain methanol concentration low and also to feed nutrient of desired C/N molar ratio.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.283-286
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• 2000

In order to maximize the cell growth and the polysaccharide production in Agaricus blazei, two kinds of fed-batch fermentation processes were performed with varying the feeding medium compositions and the feeding process. The relationship between dissolved oxygen and polysaccharide production in batch fermentation was applied to fed-batch fermentation. The biomasss concentration was 18.2 g/L and the polysaccharide production was 10.4 g/L.