• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2008년도 추계학술대회 논문집
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• pp.444-445
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• 2008

• 한국미생물·생명공학회지
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• 제14권4호
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• pp.285-291
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• 1986

효모Candida lipolytica 세포를 calcium alginate gel로 포괄 고정화시켜서. 유동층 반응기에서 반응을 수행하여 다음과 같은 결과를 얻었다. 1 고정화 효모 세포를 활성화 용액에서 회분식 유동층 반응기 방식과 연속식 유동층 반응기 방식으로 활성화시켰을 때, 세포는 고정화된 상태로 증식하였으며, 또한 세포당 시트르산 생성활성 이 증가하여서, 활성화되지 않은 bead보다 최대 시트르산 생성활성이 약 10배정도 증가되었다. 2 연속식 유동층 반응기 방식으로 활성화시킬 때가 회분식 유동층 반응기 방식으로 활성화시킬 때보다 늦은 시간에 최대의 시트르산 생성활성을 나타내었는데, 이것은 연속식으로 활성화시킬 때는 bead가 계속 새로운 환경에 놓이게 되어 bead내의 세포에 필요한 효소 및 보효소가 bead밖으로 계속 유출됨으로 인하여 bead내의 효소와 보효소의 축적에 많은 시간이 걸린데 기인한 것으로 사료된다. 3. 회분식 유동층 반응기내에서 세포수를 동일하게 하여 반응을 수행할 때, 고정화 bead의 크기가 작을수록 시트르산의 생산성이 증가하였다. 이것은 bead의 크기가 작을수록 부피에 비해 높은 표면적을 가지므로 세포의 많은 수가 반응에 참여하게 되며 bead내로의 화산저항이 작아서 물질전달이 잘되어 시트르산이 많이 생성된 것으로 사료된다.

• Mycobiology
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• 제40권1호
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• pp.35-41
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• 2012

A repeated batch fermentation system was used to produce ethanol using $Saccharomyces$ $cerevisiae$ strain (NCIM 3640) immobilized on sugarcane ($Saccharum$ $officinarum$ L.) pieces. For comparison free cells were also used to produce ethanol by repeated batch fermentation. Scanning electron microscopy evidently showed that cell immobilization resulted in firm adsorption of the yeast cells within subsurface cavities, capillary flow through the vessels of the vascular bundle structure, and attachment of the yeast to the surface of the sugarcane pieces. Repeated batch fermentations using sugarcane supported biocatalyst were successfully carried out for at least ten times without any significant loss in ethanol production from sugarcane juice and molasses. The number of cells attached to the support increased during the fermentation process, and fewer yeast cells leaked into fermentation broth. Ethanol concentrations (about 72.65-76.28 g/L in an average value) and ethanol productivities (about 2.27-2.36 g/L/hr in an average value) were high and stable, and residual sugar concentrations were low in all fermentations (0.9-3.25 g/L) with conversions ranging from 98.03-99.43%, showing efficiency 91.57-95.43 and operational stability of biocatalyst for ethanol fermentation. The results of the work pertaining to the use of sugarcane as immobilized yeast support could be promising for industrial fermentations.

• Journal of Microbiology and Biotechnology
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• 제30권8호
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• pp.1227-1234
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• 2020

In this study, yeast cell immobilization was carried out in a packed bed reactor (PBR) to investigate the effects of the volumetric capacity of carriers as well as the different fermentation modes on fuel ethanol production. An optimal volumetric capacity of 10 g/l was found to obtain a high cell concentration. The productivity of immobilized cell fermentation was 16% higher than that of suspended-cell fermentation in batch and it reached a higher value of 4.28 g/l/h in repeated batches. Additionally, using this method, the ethanol yield (95.88%) was found to be higher than that of other tested methods due to low concentrations of residual sugars and free cells. Continuous ethanol production using four bioreactors showed a higher productivity (9.57 g/l/h) and yield (96.96%) with an ethanol concentration of 104.65 g/l obtained from 219.42 g/l of initial total sugar at a dilution rate of 0.092 h^-1. Furthermore, we reversed the substrate-feed flow directions in the in-series bioreactors to keep the cells at their highest activity and to extend the length of continuous fermentation. Our study demonstrates an effective method of ethanol production with a new immobilized approach, and that by switching the flow directions, traditional continuous fermentation can be greatly improved, which could have practical and broad implications in industrial applications.

• 한국미생물·생명공학회지
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• 제17권2호
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• pp.165-169
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• 1989

고생산성의 알콜 발효용 생물반응기를 개발하기 위하여 sodium alginate로 효모균체를 고정화시킨 후 충전탑 반응기를 제조하였다. 이 때 gel속에 고정화되어 있는 세포에 산소를 공급하기 위하여 배지를 공기로 포화시킨 후 공급하였다. 그 결과 9% 포도당을 함유한 배지를 사용하였을 경우 최대 알콜생산성은 35g/$\ell$-gel-hr에서 55g/$\ell$-gel-hr로 증가되었고 90%의 전환율을 얻는데 걸리는 시간도 40분에서 25분으로 감소되었다. 즉 고정화세포 충전탑 반응기에서도 배지에 어느 정도의 산소를 공급하면 세포활성의 증가로 발효속도가 현저히 촉진됨을 알 수 있었다.

• 한국미생물·생명공학회지
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• 제14권2호
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• pp.199-203
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• 1986

Wood chip을 support로 충전한 관형발효조에 Saccharomyces formosensis 효모용액을 통과시켜 고정화한 관형발효조에서 연속 발효실험을 수행한 결과 wood chip은 support로서 높은 효모 고정화율을 나타내었다. 관형발효조에서 발효실험시 유량 및 농도의 변화시 정상상태에 도달하는데 약 60시간 소요되었고, 정상상태에서 ethanol수율은 0.473-0.483로서 회분식 발효조 경우보다 높은 값을 나타냈다. 정상상태에서 ethanol생산성 (공간체적 기준)은 ethanol농도 61.4-65.7 g/l 범위에서 24.4-19.1g EtOH/$\ell$.hr를 나타내어 다른 고정화법에 의한 것과 비슷하게 높았다. 관형발효조에서 410시간 연속 발효운전시 오염현상이 없었고 효모생존율은 88-93%로 유지되었다.

• 미생물과산업
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• 제19권4호
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• pp.2-13
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• 1993

Some microorganisms, including actinomycetes, cyanobacteria, and other bacteria, algae, fungi, and yeast, can accumulate and retain relatively high quantities of heavy metals and radionuclides from their external environments (1-4). Both living and dead cells can be used for biosorptive metal/radionuclide removal from solution. Thus microorganisms and products excreted by or derived from microbial cells (2) may provide an alternative or adjunct to conventional techniuqes of metal removal and recovery. Recent approaches have separated the microbial growth and metal removal process to manipulate production of metal-adsorptive capacity of bacteria and metal removal process. If pre-grown cells are immobilized and used for metal removal, mathematical modeling can be applied to predict immobilized cell reactor behavior under specific process conditions. Waste and microbial adsorbent could be separated from the treated flow in one step. Once treated, the metal waste is concentrated in a small volume of sorbed form for easy metal disposal or recovery.

• 한국환경과학회지
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• 제19권9호
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• pp.1177-1185
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• 2010

To examine the potency of biosorbent, the adsorption capacity of Pseudomonas cepacia H42 isolated from fresh water plant root was compared with Saccharomyces cerevisiae SEY2102 on bases of biomass, concentration of heavy metal, presence of light metals, immobilized cell, and ion exchange resin. P. cepacia H42 biomass of 0.05-0.5 g/L increased adsorption and above 1.0 g/L of yeast biomass was the most effective in adsorption. By applying the same amount of biomass, lead showed the highest adsorption on two strains and the adsorption strength was lead>copper>cadmium on both strains. The high heavy metal concentration induced the high adsorption capacity. P. cepacia H42 adsorption was in the order of copper>lead>cadmium and lead>copper>cadmium by yeast in 10 mg/L. Both strain showed same adsorption strength in the order of lead>copper>cadmium in 100 mg/L and 1000 mg/L. The adsorption capacity of both yeast and P. cepacia H42 was decreased in the presence of light metals and the order of cadmium>copper>lead. $Mg^{2+}$ induced the least adsorption while $Na^+$ induced highest adsorption. The adsorption capacity of immobilized yeast and P. cepacia H42 was detected between 200-400 mL in flow volume and decreased in the presence of light metals. Ion exchange containing light metals caused 30-50% adsorption reduction on both strains.

• KSBB Journal
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• 제25권4호
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• pp.351-356
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• 2010

리르노셀룰로오스로부터 생산된 글루코오스와 자일로 오스의 혼합당을 동시에 발효하여 에탄올 생산을 증가시키며, 또한 에탄올 생산에서의 세포고정화의 영향과 ICR (immobilized cell reactor)을 이용한 혼합당에서의 에탄올 연속생산을 수행하였다. 고정화 P. stipitis를 이용한 플라스크에서 에탄올을 생산에 대한 혼합당과 질소원의 영향으로부터 5% 혼합당 (글루코오스/자일로오스 = 3:1)과 1% 질소원이 최적으로 타나났으며, 이때 생산된 에탄올 농도는 약 19-20 g/L이었다. 고정화된 P. stipitis을 이용하여 반복적 유가식배양 (repeated fed-batch)으로 에탄올을 생산하였을 때는 모든 당 농도에서 글루코오스는 빠르게 소비되었지만, 혼합당의 농도가 높아질수록 자일로오스의 소비속도는 점차적으로 감소하였다. 즉 혼합당 농도가 증가하면서 더불어 당 소비속도는 감소하였다. 또한 ICR에서 1% 혼합당을 연속적으로 공급하면서 에탄올을 안정적으로 생산하여, 에탄올 농도는 5.6 g/L이었고 에탄올 생산 속도는 0.13 g/$L{\cdot}h$이었다.

• 상하수도학회지
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• 제25권5호
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• pp.741-750
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• 2011

A pilot-scale biofilter was constructed to discover degradation characteristics of the complex odor discharged from Ansan wastewater treatment plant. Candida tropicalis for volatile organic compounds, sulfur oxidizing bacteria(SOB) for hydrogen sulfide, and bacteria extracted from feces soil were immobilized on a polymer gel media. According to this study, the EBCT was varied from 36 sec to 18 sec. Toluene was removed as 80% along the variations, but it was recovered as 100% within 1 week. All benzene and xylene were removed during the operation while the efficiency of hydrogen sulfur was temporary decreased at 18 sec of EBCT, thereafter it was recovered to 100% within a week. The maximum elimination capacities of the benzene, toluene, xylene, and hydrogen sulfur were 6.6 g/$m^{3}$/hr, 31.7 g/$m^{3}$/hr, 7.8 g/$m^{3}$/hr, and 133.6 g/$m^{3}$/hr, respectively. There were merits on removal both organic and inorganic complex odor using the pilot-scale biofilter embedded with microorganisms immobilized on polymer gel media.