• Microbiology and Biotechnology Letters
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• v.18 no.5
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• pp.525-529
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• 1990

Plant cell cultures of Lithospermum erythrorhizon were performed in stirred tank and packed-bed reactors with in situ extraction by n-hexadecane. The specific shikonin production and volumetric shikonin productivity of stirred tank reactor reached 1.5 mg shikoninlg cell and 400$\mu g$ shikonin/(L.day), respectively. In packed-bed reactor with calcium alginate-immobilized cells specific shikonin production and volumetric productivity reached 2.0 mg shikoninlg cell and 2857$\mu g$ shikonin/(L.day), which were 1.3 and 7.1 times higher than those of stirred tank reactor, respectively. The higher shikonin production and productivity of packed-bed reactor seemed to be due to high cell loading capacity of calcium alginate immobilized cells in packed-bed reactor and improved cell-cell contact.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.8
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• pp.1022-1030
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• 1999

A numerical study was carried out to analyze the effect of flow distribution of stirred part and plug flow part on combustion efficiency at the coal gasification process in an entrained bed coal reactor. The model of computation was based on gas phase eulerian balance equations of mass and momentum. The solid phase was described by lagrangian equations of motion. The $k-{\varepsilon}$ model was used to calculate the turbulence flow and eddy dissipation model was used to describe the gas phase reaction rate. The radiation was solved using a Monte-Carlo method. One-step parallel two reaction model was employed for the devolatilization process of a high volatile bituminous Kideco coal. The computations agreed well with the experiments, but the flame front was closer to the burner than the measured one. The flow distribution of a stirred part and a plug flow part in a reactor was a function of the magnitude of recirculation zone resulted from the swirl. The combustion efficiency was enhanced with decreasing stirred part and the maximum value was found around S=1.2, having the minimum stirred part. The combustion efficiency resulted from not only the flow distribution but also the particle residence time through the hot reaction zone of the stirred part, in particular for the weak swirl without IRZ(internal recirculation zone) and the long lifted flame.

• Journal of the Korean Wood Science and Technology
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• v.31 no.6
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• pp.73-82
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• 2003

Various forest humic substances were collected at different climate regions with different forest types, and adsorption of heavy metals such as Cu(II), Zn(II), Cd(II) and Cr(III) were characteristically conducted to obtain optimal adsorption conditions and to evaluate the removal efficiency of heavy metals by each forest humic substance. The adsorption isotherms for Cu(II), Zn(II), Cd(II) and Cr(III) conformed to Langmuir's equation. In the stirred reactor, the removal efficiencies of Cu(II), Zn(II) and Cd(II) by forest humic substances were more than 90% but that of Cr(III) was less than 60%. The adsorption capacities of heavy metals in the stirred reactor were considerably varied depending on the type of forest humic substances. Among humic substances, the one from deciduous forest at subtropical region showed the highest removal efficiency for Cu(II). There was no significant difference in removal efficiency by each heavy metal depending on reaction temperature ranged from 20 to 50oC except for Cr(III), and the adsorptions of Cu(II), Zn(II) and Cd(II) were occurred rapidly in the incipient stage within 10 min, while Cr(III) needed more reaction time to be adsorbed. The stirred and packed bed column reactors showed similar adsorption characteristics of heavy metals by humic substances, but the removal efficiency was considerably higher in the packed bed column reactor than in the stirred reactor. Therefore, in actual operation process, a continuous packed bed column reactor was more economical.

• Journal of Microbiology and Biotechnology
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• v.21 no.12
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• pp.1257-1263
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• 2011

This paper is dedicated to the study on the external and internal mass transfers of glucose for succinic acid fermentation under substrate and product inhibitions using a bioreactor with stirred bed of immobilized Actinobacillus succinogenes cells. By means of the substrate mass balance for a single particle of biocatalysts, considering the kinetic model adapted for both inhibitory effects, specific mathematical models were developed for describing the profiles of the substrate concentration in the outer and inner regions of biocatalysts and for estimating the substrate mass flows in the liquid boundary layer surrounding the particle and inside the particle. The values of the mass flows were significantly influenced by the internal diffusion velocity and rate of the biochemical reaction of substrate consumption. These cumulated influences led to the appearance of a biological inactive region near the particle center, its magnitude varying from 0 to 5.3% of the overall volume of particles.

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.497-503
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• 1991

The catalytic activities of immobilized gIucoamylase in a packed bed column and a continuous stirred tank reactor have been compared. Rapid production of glucose from liquefied starch have been studied through, the continuous liquefaction and saccharification using settling chamber. The immobilized glucoamylase with chitin gave the saccharification yield of 20% with the dextrin concentration of 100 g/l in a residence of 20 min. in a packed bed column. The half-life of immobilized glucoamylase with chitin was 19 days. The glucoamyalse immobilized in chitin and encapsulated with Ca-alginate gave the saccharification yield of 6% with the dextrin concentration of 50 g/l in a residence of 20 min. in a packed bed column. The Ca-alginate encapsulated and chitin immobilized glucomylase had a half-life of 25 days, which is 6 day larger than that of the immobilized glucoamylase with chitin only. In continuous liquefaction and saccharification, the glucose yield was 17% for the liquefied starch with naked barley concentration of 50gA in a residence of 20 min.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1996.11a
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• pp.97-101
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• 1996

산림부산물인 수피에 의한 카드뮴 이온의 선택적 흡착 현상을 이용하여 인공폐수로부터 카드뮴이온의 제거를 시도하였다. 카드뮴 이온 선택성이 우수한 소나무와 상수리 나무의 수피를 이용한 효율적인 연속식 대량 수처리 시스템의 개발을 위한 기초 실험으로 카드뮴 이온흡착 등온선을 조사하였고, batch stirred reactor, airlift reactor, packed bed column 등 여러 접촉시스템에서의 카드뮴 이온의 제거 효율을 검토하였다. 카드뮴 흡착등온선은 두 수피 모두 Langmuir 형식으로 나타났으며 소나무 수피의 최대흡착용량은 약 7 mg/g, 상수리나무 수피의 경우에는 약 8 mg/g 정도로 나타났다. Batch stirred reactor를 이용한 시스템에서 초기농도 13 ppm의 카드뮴용액 100 $m\ell$ 을 수피 10 g 과 접촉시킨 결과 30분 이내에 95% 이상 제거되는 효율성을 보여주었다. Airlift reactor를 이용한 시스템에서는 수피 30 g 을 포기농도 10 ppm 카드뮴 용액 1 liter와 접촉시킨 결과 15분 이내에 93 % 이상 제거되었으며 4 cycle 반복 운전에서도 거의 같은 성능을 유지하였고 그 이상의 cycle에서는 점점 성능이 떨어짐을 보여주었다. Packed bed column을 이용한 시스템에서는 20 g의 수피를 충전시켰을 경우 초기농도 20 ppm에서 effluent 2.5 liter 까지는 95% 정도의 제거효율을 보여주었다.

• KSBB Journal
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• v.26 no.4
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• pp.328-332
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• 2011

Ethanol production using glycerol as a carbon source was performed by Enterobacter aerogenes immobilized on calcium alginate beads. To improve the ethanol production, the optimal conditions such as loading amount of immobilized cells and glycerol concentration were investigated. The optimal loading amount of immobilized cells and glycerol concentration were 10 mL of calcium alginate bead and 10 g/L, respectively. Consequently, glycerol consumption rate, ethanol concentration and yield were 0.32 g/$L{\cdot}h$, 3.38 g/L and 0.43 g/g on the batch production, respectively. Continuous production of ethanol was successfully achieved using two types of immobilized cell reactors (continuous stirred tank reactor and packed bed reactor) from 10 g/L of glycerol. In the continuous stirred tank reactor, glycerol consumption, ethanol concentration, specific productivity and yield were 9.8 g, 4.67 g/L, 1.17 g/$L{\cdot}h$, 0.48 g/g, respectively. The concentration of produced ethanol was 38-44% higher comparison to batch fermentation, and continuous stirred tank reactor showed better performance than packed bed reactor.

• Journal of Microbiology and Biotechnology
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• v.9 no.3
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• pp.292-296
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• 1999

The high density mixed mode adsorbent known by the trade name of Mimo-AD was used to purify lysozyme directly from the hen egg white (HEW). The homogenized hen egg white was treated with the adsorbent in a stirred vessel for lysozyme adsorption, and then the adsorbent, easily separated from the HEW by sedimentation, was packed into a column. The remaining HEW and contaminant proteins were removed by washing with pH 11 distilled water in an expanded-bed state, and subsequently the elution was performed with pH 12 distilled water in a packed-bed state. By this simple and rapid adsorption, washing, and elution procedure, lysozyme was purified to＞95％ with an overall recovery yield of 66％. This process offers a great potential for industrial application by allowing the extraction of lysozyme while retaining the commercial value of HEW.

• KSBB Journal
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• v.27 no.1
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• pp.28-32
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• 2012

In this study, the treatment ability of the wastewater containing perchlorate by non-salt tolerant perchlorate reducing bacterial consortium (N-PRBC) was evaluated in a continuous stirred tank bioreactor (CSTR). To obtain the optimal operating condition the bioreactor was operated with the different wastewater empty bed retention time (EBRT). The treatment performance in the bioreactor could be maintained at 100 $mg-ClO_4{^-}L^{-1}$ up to a EBRT of 3 h, and the removal capacity in the CSTR was about 3.3 times higher than that in a batch operation. With a decrease from 9 h to 2 h in a EBRT, the volumetric perchlorate reduction rate was increased from 11.1 $mg-ClO_4{^-}L^{-1}h^{-1}$ to 50.0 $mg-ClO_4{^-}L^{-1}h^{-1}$, and the specific perchlorate reduction rates were increased from 3.01 $mg-ClO_4{^-}g-DCW^{-1}h^{-1}$. In conclusion, the treatment capacities in a CSTR were much better than those obtained in a batch operation.

• KSBB Journal
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• v.15 no.1
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• pp.88-95
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• 2000

We have produced new-structured oligosaccharides using immoobilized mixed-enzyme reactor of destransucrase from Leuconostoc mesenteroides B-512FMCM and $\alpha$-amylase from Aspergillus oryzae. The reactors of immobilized mixed-exzyme beads were more efficient for the production of oligosaccharides than that of each immobilized enzyme bead in stirred-tank reactior(STR) or in packed-bed reactor(PCR). In continuous flow reactor, the immobilized mixed-enzyme bead in PBR was more stable than in STR, and 52% of initial yield was maintained for 200 hr. New structured-oligosaccharides (NOS) reduced the change of pH in the culture of Streptococcus mutans. It also showed an inhibitory effect on the growth of Staphylococcus aureus.