• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.4
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• pp.708-714
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• 1996

Ethanol production from raw starch was performed using the co-immobilized culture system of Rhizopu japonicus and zymomonas mobilis(R-Z). Glucose Production in immobilized R. japonicus culture was 2-fold higher than that in free cell culture. Ethanol production was 1.67g/L(Yp/s, 0.094) and 6.549/L(Yp/s, 0.38) in R-Z and R-Z 24 culture system, respectively. R-Z system was modified and designated as R-Z 24 system by replacing cotton plug with silicon check valve after 24h fermentation with R-Z system. Optimal substrate concentration for ethanol production in batch culture was 5%(w/v) and ethanol concentration produced was 15.02g/L(Yp/s, 0.36). Ethanol yield(Yp/s, 0.38) in fed-batch culture of 5 times with 2%(w/v) substrate was equal to that in batch culture of 2%(w/v) substrate.

• Applied Biological Chemistry
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• v.38 no.1
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• pp.20-25
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• 1995

This experiment was attempted to improve ethanol productivity by immobilization of Kluyveromyces marxianus FO43 using Jerusalem artichoke powder. Sucrose medium was used to determine optimum conditions for cell immobilization. The optimum conditions were alginate concentration of 2%, bead size of 2 mm, a particle input ratio of 30 : 100, cultivation period of 24 hours, and substrate concentration of 10%(w/v). The immobilized cells produced the high concentrations of ethanol at pH $4.5{\sim}6.5$ and $30{\sim}45^{\circ}C$, broader ranges of pH and temperatures than those of free cells. Under optimum conditions the immobilized cells showed ethanol concentration of 46.4 g/L and productivity of 1.93 g/L.h. The microphotograph using a two phase contrast microscope showed that immobilized cells cultivated under the optimum conditions were densely populated toward the surface area of beads.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.405-412
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• 1991

The enzymes were immobilized by treating the microbial cells in 0.05% chitosan and 0.28% glutaraldehyde solution. The activity of immobilized cell was about 535 IGIC/g. Glucose isomerase was purified by 6.5 times after homogenization using 60% $(NH_4)_2S0_4$ fractionation, DEAE-cellulose and Sephadex G-150 gel filtration. The molecular weight of enzyme was about 140,000 when it was measured by HPLC and the purified enzyme had only one band by electrophoresis. It showed good enzyme activity at pH 7.5 and $75^{\circ}C$. The optimum conditions for enzyme reactions were shifted to pH 7.0 and $80^{\circ}C$ when the enzyme was immobilized. The enzyme reaction was activated by the addition of 5~10 mM magnesium ion and the thermostability was improved by the addition of 0.25 mM cobalt ion. The enzyme activity was competitively inhibited by sugar alcohols.

• Applied Chemistry for Engineering
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• v.28 no.6
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• pp.685-690
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• 2017

Ammonia is a useful substance which is widely used in various industries. It is generally released by the decomposition of agricultural wastes and known to have toxic effects on human beings. Due to the common usage, it is possible to cause water pollution through either direct or indirect leakage. Such cases, it is preferable to use the adsorption capacity of zeolite to rapidly remove ammonium ions, but it is not sufficiently removed by the adsorption only. In this paper, the removal efficiency of ammonium ion through both the adsorption capacities of commercial synthetic zeolites and the biological mechanism of microorganisms were compared. In addition, microorganisms were immobilized on the zeolite in order to enhance the removal efficiency by applying a chemo-biological process. As a result, the standard commercial zeolite showed 67~81% of the removal efficiency in 2~4 hours at a 100 ppm concentration of ammonium, whereas the selected microorganism Klebsiella pneumoniae subsp. Pneumoniae showed up to 97% within 8 hours. When the microorganism was immobilized on the zeolite, the highest removal efficiency of approximately 98.5% were observed within 8 hours.

• KSBB Journal
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• v.6 no.4
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• pp.395-402
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• 1991

A new process was developed to degrade PVA(polyvinyl alcohol) in desize wastewater. Two symbiotic bacteria of Pseudomonas strain G5Y and PW were immobilized on the media by adsorption. A natural zeolite was chosen as the best media considering cell adhesion capacity, sedimentation rate, and material cost. PVA and COD removal efficiencies of this system for synthetic wastewater were 84% and 85% at the retention time of 6 hr, when the volumetric loading rate was PVA 8g/L·day and COD 8g/L·day, and cell density was 19,775 mg/L. In case of desire wastewater, they were 78% and 72% at the retention time of 6 hr, respectively, when the volumetric loading rate was PVA 8g/L·day and COD 13.2g/L·day, and cell density was 32,899mg/L. In case of desize wastewater, PVA and COD removal efficiencies were lower than synthetic wastewater, but cell density of the desize wastewater was lower than that of the synthetic wastewater, because there were insufficiency of necessary nutrition and variety of desize materials in the desize wastewater. A pilot test was successfully performed showing 88% and 82%, PVA and COD removal efficiencies at the retention time of 24 hr, when volumetric loading rate were 4.7 PVA g/L·day and COD 6.9g/L·day, and cell density was 12,,324 mg/L.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2173-2179
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• 2017

The intracytoplasmic membrane of Rhodobacter sphaeroides readily vesiculates when cells are lysed. The resulting chromatophore membrane vesicle (CMV) contains the photosynthetic machineries to synthesize ATP by ATPase. The light-dependent ATPase activity of CMV was lowered in the presence of $O_2$, but the activity increased to the level observed under anaerobic condition when the reaction mixture was supplemented with ascorbic acid (${\geq}0.5mM$). Cell lysis in the presence of biotinyl cap phospholipid (bcp) resulted in the incorporation of bcp into the membrane to form biotinylated CMV (bCMV), which binds to streptavidin resin at a ratio of approximately $24{\mu}g$ bacteriochlorophyll a/ml resin. The ATPase activity of CMV was not affected by biotinylation, but approximately 30% of the activity was lost by immobilization to resin. Interestingly, the remaining 70% of ATPase activity stayed constant during 7-day storage at $4^{\circ}C$. On the contrary, the ATPase activity of bCMV without immobilization gradually decreased to approximately 40% of the initial level in the same comparison. Thus, the ATPase activity of CMV is sustainable after immobilization, and the immobilized bCMV can be used repeatedly as an ATP generator.

• Journal of Dairy Science and Biotechnology
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• v.16 no.2
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• pp.98-105
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• 1998

Various peptides derived from food are among the most potent physiologically active agents known, and include anticancer peptides, angiotensin converting enzyme(ACE) inhibitor exhibiting antihypertension action, opioid peptides, antithrombotic peptides, hypocholesterolemic peptides, immunomodulators, calcium absorption enhancers, and other peptides. Hydrophobic peptides extracted from a Cheddar-type cheese slurry were fractionated by gel chromatography and repeated HPLC. A peptide fraction from HPLC showed high cytotoxicity on the tumor cell lines such as a human colon carcinoma, and comprised of Tyr, Ser, Leu, Gly, and others. Hypocholesterolemic peptides were isolated from peptic hydrolyzates of casein and soy proteins. Macropeptides of 1,000${\sim}$5,000 dalton were effective on reducing the cholesterol level of mouse serum. Peptides showing high Krigbaum hydrophobicity and ANS surface hydrophobicity resulted in high hypocholesterolemic effect and fecal steroid concentrations. Caseinomacropeptides(CMP) were isolated from whey powder and treated with soluble and immobilized trypsin to obtain antithrombotic peptides. One fraction from the CMP hydrolyzed with immobilized trypsin for 24h exhibited high antithrombotic activity with 52.5% inhibition of platelet aggregation. These result suggested that peptides from various milk products could be utilized as a good bioactive agents for developing health functional foods.

• The Korean Journal of Mycology
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• v.18 no.2
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• pp.84-88
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• 1990

Hydroxylation in the $11{\alpha}$-position of progesterone molecules was carried out using Rhizopus nigricans spores immobilized within various gel matrices, among which polyacrylamide and agar gel were proved to be the most effective. Reactions with the immobilized cells and in­tact free cells showed almost identical conversion rate of progesterone, optimal pH and reaction time for attaining maximal yield, from which were confirmed absence of any decay and modification of enzyme activities.

• Journal of Microbiology and Biotechnology
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• v.19 no.8
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• pp.836-844
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• 2009

A denitrification bacterium was isolated from riverbed soil and identified as Ochrobactrum sp., whose specific enzymes for denitrification metabolism were biochemically assayed or confirmed with specific coding genes. The denitrification activity of strain G3-1 was proportional to glucose/nitrate balance, which was consistent with the theoretical balance (0.5). The modified graphite felt cathode with neutral red, which functions as a solid electron mediator, enhanced the electron transfer from electrode to bacterial cell. The porous carbon anode was coated with a ceramic membrane and cellulose acetate film in order to permit the penetration of water molecules from the catholyte to the outside through anode, which functions as an air anode. A non-compartmented electrochemical bioreactor (NCEB) comprised of a solid electron mediator and an air anode was employed for cultivation of G3-1 cells. The intact G3-1 cells were immobilized in the solid electron mediator, by which denitrification activity was greatly increased at the lower glucose/nitrate balance than the theoretical balance (0.5). Metabolic stability of the intact G3-1 cells immobilized in the solid electron mediator was extended to 20 days, even at a glucose/nitrate balance of 0.1.

• 한국유가공학회:학술대회논문집
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• 1998.05a
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• pp.22-29
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• 1998

Various peptides derived from food are among the most potent physiologically active agents known, and include anticancer peptides, angiotensin converting enzyme(ACE) inhibitor exhibiting antihypertension action, opioid peptides, antithrombotic peptides, hypocholesterolemic peptides, immunomodulators, calcium absorption enhancers, and other peptides. Hydrophobic peptides extracted from a Cheddar-type cheese slurry were fractionated by gel chromatography and repeated HPLC. A peptide fraction from HPLC showed high cytotoxicity on the tumor cell lines such as a human colon carcinoma, and comprised of Tyr, Ser, Leu, Gly, and others. Hypocholesterolemic peptides were isolated from peptic hydrolyzates of casein and soy proteins. Macropeptides of 1,000${\sim}$5,000 dalton were effective on reducing the cholesterol level of mouse serum. Peptides showing high Krigbaum hydrophobicity and ANS surface hydrophobicity resulted in high hypocholesterolemic effect and fecal steroid concentrations. Caseinomacropeptides (CMP) were isolated from whey powder and treated with soluble and immobilized trypsin to obtain antithrombotic peptides. One fraction from the CMP hydrolyzed with immobilized trypsin for 24h exhibited high antithrombotic activity with 52.5% inhibition of platelet aggregation. These results suggested that peptides from various milk products could be utilized as a good bioactive agents for developing health functional foods.