• Journal of Microbiology and Biotechnology
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• 제9권2호
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• pp.132-139
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• 1999

A cell-entrapment technique using compressed air was applied to Bifidobacterium longum KCTC 3128 for the improvement of bifidobacteria viability. The main cell-entrapment matrix used was alginate, and viability improvement of the B. longum entrapped in alginate lattices was monitored along with the effects of other additional biopolymers. A prerequisite for acquiring consistent results was the uniformity of bead size and cell distribution which was achieved by using compressed air and mixing the cell suspension with sterilized alginate powder, respectively. The viability losses of the B. longum entrapped in alginate beads in the presence of three different substances logarithmically increased in relation to the reaction time, and proportionately decreased with an increased alginate concentration and bead diameter. The strongest improvement in B. longum viability was exhibited with a bead containing 3％ alginate and 0.15％ xanthan gum.

• KSBB Journal
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• 제14권4호
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• pp.389-395
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• 1999

Bifidobcterium spp. can provide human being with several beneficial physiological. Therefor, there has been a considerable interest in products Bifidobcterium spp. dietary supplements or as starter cultures for probiotic products that may assint in the improvement of health on the human. But indusrial applications have been limited because Bifidobcterium spp. are sensitive to acidic pH due to organic acid produced by themselves and various conditions. The objective of this study was to establish new method for improvement of Bifidobcterium viability by entrapment im calcium alginate beads. We have a plan to select the most suitable polymer through the comparison with acid tolerance oxygen tolerance and theological properties of polymer. Increase of the viable number of Bifidobcterium induced increasing acid tolerance and oxygen tolernce trough the development of entrapment technique. The 4%, 3030mm diameter) sodium alginate beads led to the best survivability under acid condition. Especially, addition of 6% mannitol, 6% glycerol or 6% sorbitol to the sodium alginate helped a beneficial effect on viability against acid, bile salt, hydrogen peroxide and cold strage. The number of viability of entrapeede cells by retreatment was 96 fold higher than non-entrapeed cells after 5 hours of storage under pH 3 acidic condition. These experimental data clearly demonstrate that a whole cell immobilization by entrapment in calcium alginate beads is an important survival mechanism enable to withstand environmental stresses as the acidic condition, hydrogen peroxide toxicity and frozen state.

• KSBB Journal
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• 제15권1호
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• pp.1-8
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• 2000

The diffusion effect of simulated gastric juices into the various alginate vessel containing each biopolymer such as 0.3% soluble starch, whey, corn starch, agar, locust bean gum, guar gum, gum arabic, pectin, gelatin and 0.15% xanthan gum was tested by measuring the change of pH in the vessel. The degree of viability of bifidobacteria entrapped in each bead containing biopolymers was corresponded with the degree of diffusion inhibition of hydrogen into the each vessel. Therefore, The determination of diffusion inhibition of simulated gastric juices into the various vessel by measuring the change of pH in the vessel may be effectively used as the simple method to select the optimal entrapment lattice for the improvement of bifidobacteria viability. Bifidobacteria entrapped in alginate bead containing 0.15% xanthan gum whose lattice showed the lowest hydrogen diffusion were more significantly tolerant against bile salts and hydrogen peroxide than untrapped bifidobacteria. It was also observed that the viability of bifidobacteria entrapped in bead was nto nearly changed in milk adjusted pH 4.5 with organic adids at $4^{\circ}C$ for 10 days. Therefore, use of alginate containing 0.15% xanthan gum as a cell matrix for entrapping bifidobacteria was expected to improve the viability of bididobacteria in fermented milk products and develop the high value-added products.

• Journal of Pharmaceutical Investigation
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• 제24권3호
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• pp.131-137
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• 1994

Drug delivery system by the use of red blood cells was established to sustain the release of drugs in the circulatory system by the intravenous injection. The entrapment method by the preswelling technique was re-examined and evaluated for searching the new entrapping conditions without hemolysis. The addition of 4 volume of $0.6{\times}\;hank's$ balanced salt solution (HBSS) into 1 volume of 50% red blood cells suspension did not induce the hemolysis and change the hematocrit level in this experimental condition (within 15 min). Most of daunorubicin could be entrapped into red blood cells within 15 min. While the intracellular adenosine triphosphate (ATP) level followed by the entrapment was reduced to 86% of normal ATP level, the membrane fluidity and the shape factor of red blood cells were not altered. The release rate of daunorubicin from red blood cells was affected by the hemolysis under this condition. To maintain the intracellular ATP in red blood cells, the new reaction buffer was made With the addition of ATP and sodium pyruvate during the entrapment procedure because the hemolysis during the release test would reflect the loss of intracellular ATP that might result in the decrease of the viability in vivo. The addition of ATP raised the intracellular ATP level, which protect the hemolysis during the release test.

• 멤브레인
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• 제11권2호
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• pp.89-95
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• 2001

상전환 공정을 이용하여 무기 fluor인 cerium activated yttrium silicate (CAYS)가 함침재로 존재하는 폴리설폰 고분자막을 제조하였다. CAYS가 포함된 제막용액을 물 또는 이소프로파놀의 비용매 욕조에 침지시켜 고형화시켰을 때, 막에 함침되는 CAYS는 침지용 비용매에 따라 뚜렷하게 다른 함침 특성을 나타냄으로써, 제막용액의 고형화 경로를 추적할 수 있는 역할을 하였다. 물욕조에 침지되어 고형화된 막에서 무기물인 CAYS가 고분자 구조에 달라붙은 형상을 보여준 반면, 이소프로파놀에 침지되어 형성된 막에서는 셀 같은 기공 부분에 모여있는 것이 확인되었다. 이러한 현상은 제막용액의 침지 과정에서 무기함침재들이 액체-액체 상분리에 형성된 고분자 희박지역으로 집중되었음을 확인시켜 주었다.

• KSBB Journal
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• 제4권1호
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• pp.21-30
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• 1989

Lauryl alcohol을 추출제로 사용한 에탄올 추출발효를 통하여 다음과 같은 결론을 얻을 수 있었다. 1. GC를 이용한 분배계수의 측정은 Fredenslund의 UNIFAC법을 이용한 계산치보다는 고천 낮은 값을 보이나 Minier의 측정치와는 잘 일치하고, 에탄올 농도 2-10%일때 분배계수는 0.6에 달했다. 2. 물과 에탄올은 비점이 비슷하여 95% 이상의 고순도 에탄올을 단증류로 얻기 어렵지만, LaOH는 비점($225^{\circ}C$)이 높아 에탄올과 비점차가 많이 나므로 대기압하에서 단 한번의 단증류로 87% 이상의 에탄올을 거의 모두 회수할 수 있었다. 3. TBP의 경우와 마찬가지로, LaOH의 농도가 높아 질수록 lag phase는 연장도지만, 기질 소모속 도는 추출제가 없는 경우와 비교했을때 크게 변하지 않았으며, 적응과정을 거침으로써 LaOH에 의한 lag phase 지연호과가 제거되었고, 고정화 방법 또한 lag phase를 줄이는데 교과적인 방법이었다. 4. $400\;g/\;{\ell}$ 포도당 용액의 회분 추출발생에서 LaOH/medium의 비가 4였을때 포도당은 거의 전화가 되었으며, 전체에탄올생산성은 $2.75g/\;{\ell}.hr$로 비유출의 $0.99g/\;{\ell}{\cdot}hr$보다 2.78배 증가하였다. 5. 고정화 연속 혼합 발효조에서 기질유량 $25\;{m{\ell}}/hr$, LaOH유량 $100\;{m{\ell}}/hr$일때 생산성은 $5.23\;g/{\ell}.hr$로 비유출의 $3.06\;g/{\ell}.hr$보다 1.7배 증배하였다. 6. film fermentor에서 기질농도 $200\;g/{\ell}$, 기질유출 $25\;{m{\ell}}/hr$, LaOh 유량 $100\;{m{\ell}}/hr$일때 생산성이 $5.01\;g/{\ell}.hr$로 연속 혼합 발효조에서 보다 낮은 값을 보였으나, 대체로 비슷한 양상을 보였으며, 비에탄올생산성은 고천 더 놓은 값을 나타내었고, 연속 혼합 발효조 안의 bead 내 효모보다 낮은 전단력을 받기 때문에 세포가 덜 유출되었다.