• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1978.04a
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• pp.98.1-98
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• 1978

Commensalistic system을 구성하는 B. tropicatis 와 T. cutaneum의 회분 및 연속배양을 통하여 여러 가지 동력학적 data를 구하고 mathematical model을 연구하여 다음과 같은 모형을 구성하였다. (equation omitted) 위의 모형을 computer simulation하여 정상상태와 과도상태에서의 응답을 분석하고 중요한 배양결과를 예측하였다.

• KSBB Journal
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• v.9 no.4
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• pp.400-405
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• 1994

The conditions for ${\beta}$-galactosidase production from alkalophilic, thermophilic Bacillus sp. TA-11 were investigated. The maximal enzyme production was obtained when the strain was cultured at $50^{\circ}C$ for 5 days with fed-batch culture in the optimal medium containing 1.5% lactose, 0.6% yeast extract 0.15% $K_2HP0_4$and initial pH 9.5, and then final enzyme activity under the above conditions was 5200 unit/ml of cell free extract.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.2
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• pp.156-159
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• 2001

The experiment was carried out to investigate the productivity of freshwater rotifer, Brachionus calyciflorus and marine rotifer, B. rotundiformis at various temperatures, initial inoculation and pH in a 5 L semi-continuous high density culture. Rotifers were fed by commercial condensed freshwater Chlorella. When pH was not controlled, average daily productions of freshwater and marine rotifers increased with temperature. The highest production, $44\times10^6$ rotifers, was achieved of B. calyciflorus at $32^{\circ}C$ and the possible production lasting period of B. calyciflorus was shorter than that of B. rotundiformis. Under the adjustment of pH at 7, the possible production lasting periods of B. calyciflorus and B. rotundiformis inoculated with 5,000 inds./mL were longer than those of rotifers inoculated with 10,000 inds./mL, and the daily production rate of the former was higher than that of the latter. The results from this study indicated that optimum density of the initial inoculation for the cultivation of B. calyciflorus and B. rotundiformis was 5,000 inds,/mL under the controlled conditions of pH 7 and at $32^{\circ}C$ in a semi-continuous high density culture, in terms of production rate and food cost aspects.

• KSBB Journal
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• v.11 no.1
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• pp.22-29
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• 1996

Immobilized bioprocess was carried out for continuous production of cyclosporin A (CyA) produced intracellularly as a secondary metabolite by a filamentous fungus, Tolypocladium inflatum. Immobilization procedure for entrapping conidiospores of the producer was significantly simplified by use of a modified immobilization technique. A newly-designed immobilized perfusion reactor system (IPRS) showed good process benefits as demonstrated by the role of the high density immobilized cells as an efficient biomass generator, continuously supplying highly active CyA-producing free cells (1.0g/$\ell$/hr) even at very high dilution rate ($0.1hr^{-1}$). IPRS bioprocess was possible since efficient decantor system developed in our laboratory separated the sloughed-off free cells from the immobilized biomass effectively, thus overcoming wash-out phenomenon frequently encountered in continuous free cell cultures. Furthermore the released-free cells remaining in the bulk solution did not appear to cause substrate mass transfer limitation which was often experienced in suspended mycelial fungal cell fermentations. The primary reason for this was that the suspension broth of the IPRS mainly consisted of roundshaped short mycelial fragments and conidiospores, still remaining Newtonian even at high cell density. In parallel with IPRS bioprocess development, other key factors to be considered necessarily for significant increase in CyA productivity would be strain improvement and medium optimization for the immobilized cells.

• KSBB Journal
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• v.7 no.4
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• pp.308-316
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• 1992

Two-stage continuous culture system has been studied intensively to maximize the productivity of a cloned gene product in unstable recombinant microorganism. As an effort to optimize the two-stage process, transient behavior of the second-stage was studied theoretically as well as experimentally using Escherichia coli Kl2$\delta$Hl$\delta$trp. A mathematical model describing the transient response to a step change in dilution rate was developed based on the assumption that the adaptation rate of cell growth is proportional to the available growth potential, which is defined as the difference in dilution rates between before and after shift-up. The kinetic parameters appearing in the model equations were the dimensionless step increase in growth rate($\alpha$) and the adaptation rate constant(k). These parameters were evaluated for various dilution rates and temperatures by washout method. This relatively simple adaptation model could predict the specific growth rate of the second-stage successfully. Advantage and disadvantage of the proposed model are also discussed.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.73-78
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• 2018

The main objective of this study was to evaluate the effects of acetate on the cultivation of anabena under mixotrophic condition. Four different types of acetates were used for the anebena cultivation. Among them, ethyl acetate was found to be the most effective and the growth rates linearly increased as the amount of ethyl acetate increased. When 40 mM of ethyl acetate was used, the highest values of specific growth rate of $0.979day^{-1}$ and maximum biomass productivity of $0.293g\;L^{-1}\;d^{-1}$ were obtained. On the contrary, input of acetic acid and butyl acetate inhibited the growth of anabena. For aeration tests, 0.54 vvm was optimum for anabena cultivation. For a semi-continuous cultivation test, ethyl acetate was used after 0.54 vvm test was finished. Then, test continued under 0.54 vvm and 40 mM of ethyl acetate. Lower specific growth rate and maximum biomass productivity were obtained compared to those from batch cultivation tests. However, the greatest maximum concentration of 5.91 g/L was obtained during the semi-continuous cultivation test.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.02a
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• pp.455-460
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• 2003

발효공정에 있어 배양법으로는 회분식 배양법, 연속식 배양법과 유가식(fed-batch) 배양법이 있다. 이것은 발효 과정 중 기질과 균류 등의 추가 투입 및 추출에 따른 분류로서 특히, 유가식 배양의 경우 배양액의 농도가 너무 높거나 낮으면 에탄올의 생산이 많아지거나 효모의 성장 속도가 늦어지게 된다 유가식 공정은 항생제, 비타민, 아미노산, 효소 및 재조합 단백질 등의 생산에 주로 이용된다. (중략)

• Microbiology and Biotechnology Letters
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• v.7 no.2
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• pp.71-74
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• 1979

The growth characteristics of Methylomonas methanolica YUFE 101, isolated from sewage samples, have been studied. conclusions of the study were; (1) Optimum cultivation pH and temperature are 6.3 and 32.5$^{\circ}C$ respectively (2) The specific oxygen uptake rate was 332 $\mu$ι/mg-dry weight/hr. (3) The maximum specific growth rate was 0.19 h $r^{-1}$ and celluar yield was 0.43 g-dry cell/g-methanol in batch culture, (4) The maximum biomass productivity achieved was 0.21 g-dry cel1/ι/hr at a dillution rate of 0.1 h $r^{-1}$ during continuous cultivation. (5) The contents of crude protein and total nucleic acid in the dry cell were 73 ％ and 12 ％ respectively.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.10
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• pp.919-926
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• 2009

Enrichment of anaerobic ammonium oxidation (ANAMMOX) bacteria is the essential step for operating full-scale ANAMMOX bioreactor because adding a significant amount of seeding sludge is required to stabilize the ANAMMOX reactor. In this study, the enrichment of ANAMMOX bacteria from an activated sludge using sequencing batch reactor was conducted and verified by analyzing changes in the microbial community structure. ANAMMOX bacteria were successfully enriched for 70 days and the substrate removal efficiencies showed 98.5% and 90.7% for $NH_4\;^+$ and $NO_2\;^-$ in the activity test, respectively. The phylogenetic trees of Planctomycetes phylum showed that the diverse microbial community structure of an activated sludge was remarkably simplified after the enrichment. All 36 clones, obtained after the enrichment, were affiliated with ANAMMOX bacteria of Candidatus Brocadia (36%) and Candidatus Anammoxoglobus (64%) genera. The quantification using real-time quantitative PCR (RTQ-PCR) revea ed that the 16S rDNA concentration of ANAMMOX bacteria was 74.8% compared to the granular ANAMMOX sludge obtained from an upflow ANAMMOX sludge bed reactor which had been operated for more than one year. The results of molecular analysis supported that the enriched sludge could be used as a seeding sludge for a full-scale ANAMMOX bioreactor.

• KSBB Journal
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• v.16 no.3
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• pp.274-280
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• 2001

A serum-free media for CRIP/MFG-LacZ retrovirus production was developed and applied to continuous packed-bed culture system. The serum-free media developed by fractional factorial design contains indulin ($10\mug/mL$), transferrin ($5\mug/mL$), BSA (4 mg/mL), EGF (25 ng/mL), and linoleic acid ($10\mug/mL$). Operation of continuous packed-bed reactor using Fibra-cel enabled the packging cell to stably maintain retrovirus titer for about 1 week. The optimal operation conditions for dilution rate and temperature were 0.67(h(sup)-1) and $32^{circ}C$, respectively. Using this media, the retrovirus titer(cfu/mL) in the packed continuous culture was about 50% that of continuous culture with serum containing DMEM media.