• KSBB Journal
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• 제15권5호
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• pp.489-496
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• 2000

고농도 유전자 재조합 대장균을 이용하여 pyruvate dehy-drogenase complex-E2 특이성 인간 모노클론 항체의 Fab 부분을 효율적으로 생산하기 위해 회분식, 이단 연속식, 반 유 가식, two-stage cyclic fed-batch 동 여러 가지 배양 방법이 조사되었다. 먼저 플라스미드 안정성 문제를 극복하기 위해 growth stage와 production stage를 분리하는 two-phase 회분식 배양과 이단 연속식 시스템을 시도하였다 그 결과 two-phase 회분식 배양보다는 이단 연속식 배양에서의 세포농도와 항체 생산성이 우수하였다 또한 이단 연속식 배양에서의 세포 성 장과 항처l 생산성은 용존산소를 제어한 경우가 그렇지 않은 경우보다 월등하게 높았다. 그리고 plasmid 안정성에 있어서 는 실험기간 내에 거의 100%를 유지하여 높은 안정도를 보 여주었다. 유가식 공정에 적합한 공급 배지로 변형된 M9 배 지가 최적배지로 선정되었고 이 배지 중 최적의 CjN 비율을 조사한 결파 2:3으로 결정되었다. 반 유가식 시스템에서 constant feeding 전략을 사용할 경우 최적 공급속도는 $0.6g/\ell/hr$이었다. 또한 pulse에 의해 공급배지를 공급할 경우에는 총 공급 량이 같을 경우 소량으로 자주 공급해 주는 것이 공급배지를 한꺼번에 많은 양을 공급해주는 것 보다 바람직하였다. 여러 가지 feeding 전략을 조사해 본 결과 linear feeding 방법이 가장 효과적이었다. 하지만 linear feeding 방법마저도 고농도 세포배양에 한계가 있었기 때문에 pH-stat 방법을 이용한 two-stage cyclic fed-batch 시스템을 시도하여 $54 g/\ell$의 세포 를 얻을 수 있었다. 따라서 이 방법이 일단 생산성 향상을 위한 세포의 고농도 배양에는 조사한 여러 배양 시스템 중에 가장 효율적인 시스템임올 알 수 있었다 하지만 이 시스템 에서 포도당을 낮은 level로 유지할 수 있었으나, 초산의 과도한 축적으로 항체 생산성의 향상은 예상에 비해 크지 않았다.

• 대한산업공학회지
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• 제38권2호
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• pp.89-97
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• 2012

This paper considers a manufacturer with a two-station make-to-stock and make-to-order serial production system. The MTS facility produces a single type of component and provides components for the MTO facility that produces customized products. In addition to the internal demand from the MTO facility, the MTS facility faces demands from the spot market with the option of to accept or reject each incoming demand. This paper addresses a joint component inventory rationing and batch production control which maximizes the manufacturer's profit. Using the Markov decision process model, we investigate the structural properties of the optimal inventory rationing and batch production policy, and present two types of heuristics. We implement a numerical experiment to compare the performance of the optimal and heuristic policies and a simulation study to examine the impact of the stochastic process variability on the inventory rationing and batch production control.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.459-462
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• 2000

The pretreatment of used newspaper for the enzymatic digestion preprocess was performed on a percolation reactor and a batch reactor. The test condition of percolation process was $170^{circ}C$, 60min, 1 mL/min, and 400psi, that of batch was $40^{circ}C$, 3hr. and latm Reaction solutions used in pretreatment process were aqueous ammonia, sulfuric acid, water, and hydrogen-peroxide as an oxidizing agent. As a result, the effect of pretreatment was similar to batch and percolation process, but the yield of enzymatic hydrolysis was higher in batch than percolation. This batch pretreatment enhanced enzymatic hydrolysis rate and increased glucose yield from about 15 to 20%. The inhibition factors influenced the rate of enzymatic hydrolysis was investigated, and the ink contented newspaper was the major factor.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.410-413
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• 2001

In this study a repeated batch production of lactic acid was investigated for the purpose of reducing amount of yeast extract dosage. First batch operation was performed with nutrient rich media(glucose 100-150 g/${\ell}$, and high yeast extract contents; 15 g/${\ell}$), and subsequential batch operations were performed with nutrient poor media(glucose 100-150 g/${\ell}$, and reduced yeast extract contents; 4-5 g/${\ell}$). Volumetric productivities(6.03-6.20 g/${\ell}{\cdot}h$) and substrate conversion rate(94-98%) of eve η subsequential batch operation were maintained with the same level of first batch operation(6.19 g/${\ell}{\cdot}h$, and 99%, respectively), when concentrations of glucose and yeast extract were 100, and 4 g/${\ell}$ respectively.

• KSBB Journal
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• 제15권3호
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• pp.247-253
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• 2000

This study was aimed to enhance polycyclic aromatic hydrocarbon(PAHS) biodegradation rate by repeated-batch treatment using immobilized cells of Phanerochaete chrysosporium. In the repeated-batch operations with 30 mg/L of pyrene the maximum degradation rate was 6.58 mg/L day. As the number of batches increased the concentration of immobilized cells significantly decreased and the degradation rate and specific acitivity gradually increased to a maximum value and then decreased. To have PAH degradation activity and cell mass recovered one batch of cultivation using the growth medium instead of the PAH-degrading medium was carried in the course of repeated-batch operations. This maximum degradation rates of pyrene and anthracene were 4.29 and 4.46 mg/L$.$day respectively. Overall the rate of PAH degradation could be enhanced 2.5-30 folds by using immobilized cells compared to the case of using suspended cells.

• Journal of Microbiology and Biotechnology
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• 제11권1호
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• pp.13-16
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• 2001

Maltose and soluble starch were used as secondary sources of carbon for glucoamylase production by Aspergillus awamori in solid state fermentation. During batch cultivation, maltose above 2.5%(w/w) repressed glucoamylase production, but, by adding either 2.5% (w/w) maltose or 1.25% (w/w) soluble starch to fed-batch cultivations, glucoamylase activity was increased by 15% and 170% over standard medium, respectively. The data showed that maltose is a weak inducer of glucoamylase production in solid stat fermentation.

• 한국가스학회지
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• 제5권1호
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• pp.21-28
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• 2001

회분식 공정의 HAZOP 분석 전문가 시스템은 연속 공정의 HAZOP 분석 기법과는 달리 time과 sequence라는 이산적인 변수들을 고려해야 한다. 따라서 본 연구에서는 이산 변수들과 연속 변수들의 관계를 이용하여 회분식 공정의 time과 sequence 해석을 수행하는 회분식 공정의 HAZOP 분석 자동화를 위한 전문가 시스템을 개발하였다. 제안된 전문가 시스템을 Latex 제조 공정에 적용하여 그 실효성을 검토하였다.

• 한국가스학회지
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• 제3권2호
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• pp.34-42
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• 1999

회분식 공정의 HAZOP 분석 기법은 연속 공정의 HAZOP 분석 기법과는 달리 time과 sequence라는 이산적인 변수들을 고려해야 한다. 회분식 공정의 time과 sequence 해석은 연속 공정의 HAZOP 분석 기법으로는 설명될 수 없으므로, 이산 변수들과 연속 변수들의 관계를 이용하여 회분식 공정의 HAZOP 분석을 수행하는 방법을 개발하였다 본 연구에서는 이 방법을 Latex 제조 공정에 적용하여 그 실효성을 검토하였다.

• Journal of Microbiology and Biotechnology
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• 제4권4호
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• pp.333-337
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• 1994

In order to develop the whey beverage, we examined the optimum conditions for alcohol fermentation by Kluyveromyces tragilis ATCC 46537. The optimum conditions for alcohol production by K. fragilis ATCC 46537 were as follows; pH 4.5, $30^{\cir}C$, with a supplement of 50 g/l of lactose. To develop a continuous production of alcohol from whey, we compared batch fermentation with continuous iermentation in conjunction with UF system. Batch fermentation produced 11.0 g/l of alcohol, whereas pseudocontinuous and continuous fermentation with UF system produced 8.5 g/l of alcohol. To increase the alcohol production, we added 50 g/l of lactose to both fermentations. Batch fermentation with lactose supplement produced 15.7 g/l of alcohol and continuous fermentation with lactose supplement in conjunction with UF system produced 15.0 g/l of alcohol. These results clearly demonstrate that the UF system can be used to increase the alcohol production from whey, supplemented with exogenous lactose.

• 상하수도학회지
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• 제20권3호
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• pp.443-450
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• 2006

For understanding sludge concentration profile as a function of time, sludge was sampled at each sampling port. When sludge concentration was 3g/L, the vertical sludge concentration distribution was similar to that of 2g/L of sludge concentration. During the early stage of sludge settling, sludge concentration increased remarkably as the sludge interface height in batch column became lower. The higher sludge concentration became, the worse sludge setteability became. Also, the type of sludge settling was influenced with sludge concentration gradient in batch column. In the same concentration, the greater sludge concentration gradient was, the faster sludge interface settled down. And the changing sludge concentrations in a batch settling or a continuous settling were simulated by using the equation of sludge interface height change model.