• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.136-138
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• 2002

In this work we describe the on-line monitoring technique for the analysis of fumaric acid in biotechnological processes. Fumarase and malate dehydrogenase(MDH) were immobilized on epoxy carrier and integrated into a FIA system. The effects of carrier buffer flow rate, pH, reaction temperature on the immobilized fumarase/MDH were investigated for the development of a fumarate-FIA system. Furthermore the effects of substrates, salts and metabolites dissolved in the sample on the activity of the immobilized enzyme were investigated.

• KSBB Journal
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• 제17권4호
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• pp.339-344
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• 2002

Flow injection analysis technique for monitoring of xylitol concentrations in biological processes has been developed using xylitol oxidase (XYO) immobilized on VA-Epoxy Biosynth carrier. The immobilized XYO cartridge has been integrated into a FIA system with an oxygen electrode and systematically investigated with regards to the factors which can affect the activity of the immobilized XYO, such as pH, temperature, salt concentration etc. The activity of the immobilized XYO increased with the temperature ($19.0 - 29.0^{circ}C$) and sample injection volume ($75-250\muL$) and molarity of potassium phosphate buffer (0.1-1 M), but it reached the highest value at pH 8.5. The XYO-FIA system has been also applied for on-line monitoring of xylitol concentrations in a reactor and showed good operational stability and agreement with off-line data measured with HPLC.

• KSBB Journal
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• 제15권2호
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• pp.139-144
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• 2000

알콜증류폐액에 빵효모를 배양하는 중에 glucose와 ammon-ium을 자동첨가하여 균체량을 효율적으로 증가시킴으로써 폐액의 재이용성을 향상시키고자 하였다. Glucose는 DO를 제어파라미터로 하는 제어방법을 사용하여 116 mg/L 이하로 자동제어하였다. Ammonium의 경우에는 FIA를 이용한 온라인 자동계측제어장치와 프로그램을 이용하여 배양액의 ammon-ium 농도를 자동분석하고 제어하였으며, ammonium 농도를 류.0~27.7 mM의 낮은 농도범위로 유지시킬 수 있었다. Ammo-nium 농도를 제어한 본 실험의 최대비증식속도는 0.21 hr-1이었고, 대당균체수율은 약 0.78 g/g 으로서 ammonium 농도를 제어하지 않은 경우에 비하여 대당균체수율은 약 1.4배, 최대비증식속도는 1.2배 더 높아졌으므로 ammonium 제어에 의하여 균의 glucose 이용효율이 더욱 향상되었다. 대암모늄균체수율은 약 11.3 g/g 이었다. Glucose와 ammonium을 첨가함으로써 균체량을 18.5 g/L 까지 높일 수 있었으며, 이는 첨가하지 않은 경우보다 7.1배 더 높은 균체량에 해당한다. Glucose와 ammonium의 농도를 낮게 유지시킬 수 있었으므로 두가지 영양성분의 경제적인 공급이 가능하였다.

• Bulletin of the Korean Chemical Society
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• 제32권9호
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• pp.3437-3442
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• 2011

An on-line flow injection analysis with dual pre-concentration method was developed to determine the ultra trace tri and hexavalent chromium in water. In this system, the cation and anion pre-concentration columns were combined with a 10-port injection valve and then used to separate and concentrate Cr (III) and Cr (VI) selectively. The two species of concentrated chromium were sequentially eluted and determined by using HCl-KCl buffer of pH 1.8 as an eluent. Cr (III) was oxidized by hydrogen peroxide to Cr (VI). It was detected spectrophotometrically at 548 nm by complexation with DPC (diphenylcarbazide). Several factors such as concentration of $H_2O_2$, DPC and coil length in reaction condition were optimized. The linear range for Cr (III) and Cr (VI) was 0.1-50 ${\mu}g$/L. The limit of detections ($3{\sigma}$) of Cr (III) and Cr (VI) were 52 ng/L and 44 ng/L under the optimized FIA system, and their recoveries 98% and 103%, respectively. This method was applied to analyze contamination level of chromium species in tap water, groundwater and bottled water.

• Journal of Biosystems Engineering
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• 제28권5호
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• pp.465-468
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• 2003

A microdialysis coupled flow injection amperometric biosensor was calibrated to measure the concentration of glucose using 7 standard samples from 10ml to 70ml of glucose solution. The output of the sensor increased linearly with an increase in the glucose concentration with an $R^2$ correlation of 0.99. The amperometric biosensor was then applied to measure the. glucose concentration of 2 commercial samples(Orange and Pineapple juice) and the results compared with HPLC. Around 12% error was observed in glucose concentration measurements of the samples analyzed. The sensor has potential in rapid measurement once the calibration is done. Potential for on-line sensing is also discussed.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.173-176
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• 2000

A neural network based controller (NN controller) was studied for the control of ammonia concentrations in biological processes. An ammonia FIA has been employed to on-line monitor the concentrations of ammonia in a bioreactor. The optimal neural network structure was investigated by computer simulation and found to be a 3(inputlayer)-2(hidden layer)-1(output layer). The NN controller had advantage over the PID controller, even though the former is more time consuming. The 3-2-1 NN controller has been used to control the ammonia concentrations in a simulated bioprocess and also in a real cultivation process of yeast, and its performance were investigated.

• Journal of Biosystems Engineering
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• 제30권5호
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• pp.312-317
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• 2005

A flow injection type biosensor was tested to confirm the performance of a batch and a continuous type flow injection unit. Reproducibility and consistence of the biosensor were investigated to determine the effect of pulsations and air bubbles, and the applicability of on-line monitoring. The air bubbles affected the performance of the sensor irrespective of the location, and also the pulsations of the pump influenced the performance of the sensor. The applicability of on-line motoring was accepted as the result of the repeated and long-term measurements.

• KSBB Journal
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• 제16권5호
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• pp.452-458
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• 2001

생물공정에서 암모니아 농도를 제거하기 위해 NN 제어기를 개발하였고 기존의 PID 제어기와 비교하였다. 특히, 생물반응기내 암모니아 농도를 온라인 모니터링하기 위해 암모니아-FIA 장치를 사용하였으며, 이 장치의 분석 오차, 분석 시료의 체류 시간 등의 제어 특성에 대한 영향 computer simulation을 통해 비교, 고찰하였다. 또한 computer simulation에 의해 생물공정에 적합한 인공 신경망 제어구조를 고찰하였고, 3-2-1 구조의 NN 제어기가 PID 제어기보다 우수함을 알수 있었다. 3-2-1 구조의 NN 제어기를 이용하여 모사 생물공정 및 yeast 발효공정에서 암모니아 농도를 제어하여 그 특성을 고찰하였다. 본 연구로부터 미생물의 비선형성장 특성을 가진 생물공정에서 기질의 농도를 제어하기 위해서는 3-2-1 구조의 인공 신경망 제어기가 적합함을 알 수 있었다.

• Journal of Biosystems Engineering
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• 제31권5호
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• pp.443-448
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• 2006

For development of an on-line monitoring unit of fermentation process, an auto dilution unit based on traditional chemical and biological analytical method was developed and the performance was evaluated. The dilution unit was constructed with two syringe pumps and flow direction change valves and fully automated. Total delivery volume of two pumps using distilled water was measured to confirm the operating stability And diluted concentrations of three substrate solutions (glucose, lactic acid, ethanol) were compared with a standard method with a high performance liquid chromatograph (glucose, lactic acid) and gas chromatograph (ethanol). Relative error values of total delivery volume of the pumps were below 3% and standard deviation values were 0.003 (n=5). Relative error values of diluted concentration of the dilution unit measurements were below 2% with 1/10 of dilution ratio and 70, $80{\mu}{\ell}$ of sample volume conditions for glucose and lactic acid, 1/30 of dilution ratio and $70{\mu}{\ell}$ of sample volume conditions for ethanol, respectively. In case of the ethanol, cause of the evaporative characteristics, the relative error values showed over 5% whole experimental conditions.