• Microbiology and Biotechnology Letters
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• v.51 no.2
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• pp.184-190
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• 2023

Bioethanol has recently attracted much attention as a sustainable and environmentally friendly alternative energy source. This study aimed to develop a potential process for bioethanol production by fed-batch fermentation using instant dry yeast. To obtain the highest cell growth, we studied the influence of the initial sugar concentrations and pH of sugarcane molasses in batch fermentation. The batch system employed three levels of sugar concentrations, viz. 10%, 15%, 20% (w/v), and two levels of pH, 5.0 and 5.5. The highest cell growth was achieved at 20% (w/v) and pH 5.5 of molasses. The fed-batch system was then performed using the best batch fermentation conditions, with a molasses concentration of 13% (w/v) which resulted in high ethanol concentration and fermentation efficiency of 15.96% and 89%, respectively.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.177-179
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• 2002

The process for the production of mannitol with fructose (5% to 25%) using Leuconostoc mesenteroides NRRL B-1149 was investigated. Optimization study for mannitol production was carried out in 8 liter batch or fed-batch cultures at $28^{\circ}C$, pH 5.0, without aeration. When 5% fructose was used in a batch culture fermentation, the yield of mannitol was 78% of theoretical. As the concentration of fructose was increased to 10% in a batch culture, the yield was reduced to 59.6% of theoretical. Using a fed-batch fermentation with 10% fructose, the yield was increased to 81.9%. When 15% fructose was used for a fed batch fermentation 5% fructose was initially added and the last 10% fructose was supplied continuously. The final yield of mannitol was 83.71% of theoretical. When 20% fructose was used, the yield was more higher, 89.48%.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1979.10a
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• pp.242-242
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• 1979

The general efforts of applied research and development can be divided into product development, process development, process design, process equipment design, and operation The fed batch culture as one effort of theprocess development in fermentation industry has been practiced since the early times of human history. One particular industrial application with long history is in the cultivation of the baker's yeast where the glucose effect at relatively high glucose concentration is the general rule.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.4
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• pp.254-254
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• 2002

A process for the production of mannitol from fructose (5% to 25%) using Leuconosyoc mesenteroides NRRL B-1149 was investigated. Fermentations were carried out in bat도 of fed-batch fermentations without aeration at 28℃, pH 5.0. When 5% fructose was used in batch culture fermentation, the yield of mannitol was 78% of that expected theoretically. When the fructose concentration was increased to 10%, the yield dropped to 59.6% of the theoretical value. However, in the fed-batch culture, using 10% fructose, the yield was 81.9% of the theoretical value. In a 15% fructose fed-bat도 culture, with 5% fructose being added initially and the other 10% fructose being added as a continuous supply, the final yield was 83.7% of the theoretical yield. When 20% fructose was used in the same manner, the yield was 89.5% of theoretical yield.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.5
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• pp.275-280
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• 2002

In order to control glucose concentration during fed-batch culture for antibiotic production, we applied so called “software sensor” which estimates unmeasured variable of interest from measured process variables using software. All data for analysis were collected from industrial scale cultures in a pharmaceutical company. First, we constructed an estimation model for glucose feed rate to keep glucose concentration at target value. In actual fed-batch culture, glucose concentration was kept at relatively high and measured once a day, and the glucose feed rate until the next measurement time was determined by an expert worker based on the actual consumption rate. Fuzzy neural network (FNN) was applied to construct the estimation model. From the simulation results using this model, the average error for glucose concentration was 0.88 g/L. The FNN model was also applied for a special culture to keep glucose concentration at low level. Selecting the optimal input variables, it was possible to simulate the culture with a low glucose concentration from the data sets of relatively high glucose concentration. Next, a simulation model to estimate time course of glucose concentration during one day was constructed using the on-line measurable process variables, since glucose concentration was only measured off-line once a day. Here, the recursive fuzzy neural network (RFNN) was applied for the simulation model. As the result of the simulation, average error of RFNN model was 0.91 g/L and this model was found to be useful to supervise the fed-batch culture.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.4
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• pp.234-236
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• 2002

A process for the production of mannitol from fructose (5% to 25%) using Leuconostoc mesenteroides NRRL B-1149 was investigated. Fermentations were carried out In batch or fed-batch fermentations without aeration at 28$\^{C}$, pH 5.0. When 5% fructose was used In batch culture fermentation, the yield of mannitol was 78% of that expected theoretically. When the frurtose concentration was Increased to 10%, the yield dropped to 59.6% of the theoretical value. However, In the fed-batch culture, using 10% fructose, the yield was 81.9% of the theoretical value. In a 15% fruttose fed-batch culture, with 5% fructose being added initially and the other 10% fructose being added as a continuous supply the final yield was 83.7% of the theoretical yield. When 20% fructose was used In the same manner, the yield was 89.5% of theoretical yield.

• Journal of Microbiology and Biotechnology
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• v.25 no.6
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• pp.814-819
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• 2015

The natural crosslinking agent genipin has been applied widely in biomedicines and foods nowadays. Because of the special hemiacetal ring structure in its molecule, it can only be prepared by hydrolysis of geniposide according to biocatalysis. In this research, strategies including aqueous-organic biphasic catalysis and substrate fed-batch mode were adopted to improve the biocatalysis process of genipin. A 10 L ethyl acetate-aqueous biphasic system with geniposide fed-batch led to a satisfying genipin yield. With Fusarium solani ACCC 36223, 15.7 g/l genipin in the ethyl acetate phase was obtained, corresponding to space-time yields of 0.654 g l^-1 h^-1.

• Microbiology and Biotechnology Letters
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• v.21 no.4
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• pp.354-365
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• 1993

A novel control method with automatic tuning of PID controller parameters has been developed for efficient regulation of dissolved oxygen concentration in fed-batch fermentations of Escherichia coli. Agitation speed and oxygen partial pressure in the inlet gas stream were chosen to be the manipulated variables. A heuristic reasoning allowed improved tuning decisions from the supervision of control performance indices and it coule obviate the needs for process assumptions or disturbance patterns. The control input consisted of feedback and feedforword parts. The feedback part was determined by PID control and the feedforward part is determined from the feed rate. The proportional gain was updated on-line by a set of heuristics rules based on the supervision of three performance indices. These indices were output error covariance, the average value of output error, and input covariance, which were calculated on-line using a moving window. The integral and derivative time constants were determined from the period of output response. The specific growth rate was maintained at a low level to avoid acetic acid accumulation and thus to achieve a high cell density. The specific growthe rate was estimated from the carbon dioxide evolution rate. In fed-batch fermentation, the simutaneous control of dissolved oxygen concentration (at 0.2; fraction of saturated value) and specific growth rate (at 0.25$hr^{-1}$) was satisfactory for the entire culture period in spite of the changes in the feed rate and the switching of control input.

• Journal of Microbiology and Biotechnology
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• v.24 no.1
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• pp.59-69
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• 2014

One of the major challenges in metabolic engineering for enhanced synthesis of value-added chemicals is to design and develop new strains that can be translated into well-controlled fermentation processes using bioreactors. The aim of this study was to assess the influence of various fed-batch strategies in the performance of metabolically engineered Pseudomonas putida strains, ${\Delta}gcd$ and ${\Delta}gcd-pgl$, for improving production of medium-chain-length polyhydroxyalkanoates (mcl-PHAs) using glucose as the only carbon source. First we developed a fed-batch process that comprised an initial phase of biomass accumulation based on an exponential feeding carbon-limited strategy. For the mcl-PHA accumulation stage, three induction techniques were tested under nitrogen limitation. The substrate-pulse feeding was more efficient than the constant-feeding approach to promote the accumulation of the desirable product. Nonetheless, the most efficient approach for maximum PHA synthesis was the application of a dissolved-oxygen-stat feeding strategy (DO-stat), where P. putida ${\Delta}gcd$ mutant strain showed a final PHA content and specific PHA productivity of 67% and $0.83g{\cdot}l^{-1}{\cdot}h^{-1}$, respectively. To our knowledge, this mcl-PHA titer is the highest value that has been ever reported using glucose as the sole carbon and energy source. Our results also highlighted the effect of different fed-batch strategies upon the extent of realization of the intended metabolic modification of the mutant strains.

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.504-508
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• 1991

$1.85\times 10^{-10}$ (mmole/cell/h) of specific glucose consumption rate was obtained under fed-batch cultivation of recombinant mamalian ce11s with maintaining $4.7\times 10^{-7}(\mu g/ceil/h)$ of average specific erythropoeitin production rate. Higher maximum cell density was also achieved than for both cases of batch and perfusion cultivations. It proves that glutamolysis dominates metaboiic pathways at latter period of cultivation where quasi steady state was maintained. Substrate limitation of glucose concentration was estimated as 13 (mmole/l) under fed-batch conditions. while specific product production rate was decreased according to cultivation time, erythropoeitin production was increased as glucose concentration in the media increased up to 13.2 (mole/l).