Yong Bok Choi - Academia.edu (original) (raw)

Papers by Yong Bok Choi

Research paper thumbnail of Antimicrobial Activity and Cytotoxicity of Prepolymer Allyl 2-cyanoacrylate and 2-Octyl Cyanoacrylate Mixture Adhesives for Topical Wound Closure

Materials

The development of a new skin adhesive that can be used inside and outside the body, which preven... more The development of a new skin adhesive that can be used inside and outside the body, which prevents infection and has fewer scars and less side effects, is currently attracting attention from the scientific community. To improve biocompatibility, prepolymer allyl 2-cyanoacrylate (PAC) and 2-octyl cyanoacrylate (OC) were mixed in various proportions and tested for their therapeutic potential as skin adhesives. A series of skin adhesive samples prepared by mixing PAC, OC, and additives with % (w/w) ratios of 100:0:0, 0💯0, 70:0:30, 40:30:30, and 30:40:30 were tested to determine their antimicrobial activity, cell cytotoxicity, and formaldehyde release. The additives include myristic acid and dibutyl sebacate as plasticizers and butylated hydroxyanisole as an antioxidant. It was observed that the samples containing 70% PAC (PAC7) or 40% PAC (PAC4) with 30% additives had the highest antimicrobial activities against various microbial cells and no cytotoxicity regarding in vitro fibrob...

Research paper thumbnail of Biodegradation of inhibitory aromatic solvents in a novel bioreactor = 새로운 생물반응기를 이용한 독성방향족 용매의 생물학적 분해

Research paper thumbnail of Biodegradation of Toluene using Biofilms in a Bubble Column Bioreactor

Biodegradation of toluene in liquid effluent stream was carried out using biofilms of Pseudomonas... more Biodegradation of toluene in liquid effluent stream was carried out using biofilms of Pseudomonas putida formed on celite particles in the bubble column bioreactor. Silicon rubber tubing was installed at the bottom of the bioreactor and liquid toluene was circulated within the tubing. Toluene diffused out of the tube wall and was transferred into the culture broth where degradation by biofilms occurred. The operating variables affecting the formation of biofihns on celite particles were investigated in the bubble column bioreactor, and it was found that formation of bifilm is favored by high dilution rate and supply rate of carbon source which stimulate the growth of initially attached cells. Continuous biodegradation of toluene using biofilms was stablely conducted in the bioreactor for more than one month without any significant fluctuation, showing a removal efficiency higher than 95% at the toluene transfer rate of 1.2 g/L/h.

Research paper thumbnail of Pseudomonas SP, HN-72 and Purification Method of 2,6-NAPHTHALENE Dicarboxylic Acid Using the Same

Research paper thumbnail of A novel bioreactor for the biodegradation of inhibitory aromatic solvents: Experimental results and mathematical analysis

Biotechnology and Bioengineering, 1992

A novel bioreactor for the biodegradation of toxic aromatic solvents, such as benzene, toluene, a... more A novel bioreactor for the biodegradation of toxic aromatic solvents, such as benzene, toluene, and xylenes in liquid effluent stream, was developed. Silicon tubing was immersed in the completely mixed and aerated bioreactor, and liquid toluene as a model solvent was circulated within the tubing. Toluene diffused out of the tube wall and was transferred at high rate into the culture broth, where biodegradation occurred. The effect of operating parameters on the toluene transfer rate was investigated. During continuous operation, the biodegradation rate was considerably higher than those obtained using conventional methods. A mathematical model was established for continuous biodegradation, and simulation results coincided with the experimental results. The performance and operational criteria of the bioreactor were analyzed on the basis of both the experimental and simulation results. © 1992 John Wiley & Sons, Inc.

Research paper thumbnail of A novel biotransformation of 2-formyl-6-naphthoic acid to 2,6-naphthalene dicarboxylic acid by Pseudomonas sp. for the purification of crude 2,6-naphthalene dicarboxylic acid

Biotechnology Letters, 2008

Crude 2,6-naphthalene dicarboxylic acid was purified by Pseudomonas sp. HN-72 which biotransforme... more Crude 2,6-naphthalene dicarboxylic acid was purified by Pseudomonas sp. HN-72 which biotransformed the major impurity of 2-formyl-6-naphthoic acid into 2,6-naphthalene dicarboxylic acid. The biotransformation yield reached 100% when the reaction was performed at 40°C for 1 h, in 200 ml KH2PO4/KOH buffer (50 mM, pH 8.0), with 0.2% (w/v) crude 2,6-naphthalene dicarboxylic acid and 2.5 mg dry cell wt/ml.

Research paper thumbnail of A novel method to supply the inhibitory aromatic compounds in aerobic biodegradation process

Biotechnology Techniques, 1992

To efficiently supply inhibitory aromatic solvents such as benzene, toluene, and xylenes in liqui... more To efficiently supply inhibitory aromatic solvents such as benzene, toluene, and xylenes in liquid phase for aerobic biodegradation processes, a novel technique was developed. Silicon tubing was immersed in the bioreactor and liquid solvent was circulated within the tubing from a solvent reservoir. Transfer rate of the solvent through a silicon tubing was significantly affected by impeller speed, whereas other operating parameters such as aeration rate and circulation rate of liquid solvent within the tubing showed a negligible effect. Aerobic biodegradation of toluene and p-xylene was carried out using this method and the biodegradation rate of solvent mixture was high compared to those of conventional methods.

Research paper thumbnail of Simultaneous biodegradation of toluene and p-xylene in a novel bioreactor: experimental results and mathematical analysis

Biotechnology Progress, 1993

Simultaneous biodegradation of toluene and p-xylene was performed in a novel bioreactor, and the ... more Simultaneous biodegradation of toluene and p-xylene was performed in a novel bioreactor, and the performance was analyzed on the basis of both experimental and mathematical simulation results. The novel bioreactor employed a silicon tubing as a supplier of the aromatic solvents to be treated, and the transfer rate of toluene and p-xylene into the culture broth was easily controlled. Batch, sequencing batch, and continuous mode of operation were carried out in the novel bioreactor to compare the performance of the biodegradation of solvent mixture. Sequencing batch operation worked well, but several operational difficulties were found. Continuous operation was shown to present higher biodegradation rates and operational stability. The continuous biodegradation process was mathematically simulated, and operational conditions were optimized on the basis of the simulation results.

Research paper thumbnail of Antimicrobial Activity and Cytotoxicity of Prepolymer Allyl 2-cyanoacrylate and 2-Octyl Cyanoacrylate Mixture Adhesives for Topical Wound Closure

Materials

The development of a new skin adhesive that can be used inside and outside the body, which preven... more The development of a new skin adhesive that can be used inside and outside the body, which prevents infection and has fewer scars and less side effects, is currently attracting attention from the scientific community. To improve biocompatibility, prepolymer allyl 2-cyanoacrylate (PAC) and 2-octyl cyanoacrylate (OC) were mixed in various proportions and tested for their therapeutic potential as skin adhesives. A series of skin adhesive samples prepared by mixing PAC, OC, and additives with % (w/w) ratios of 100:0:0, 0💯0, 70:0:30, 40:30:30, and 30:40:30 were tested to determine their antimicrobial activity, cell cytotoxicity, and formaldehyde release. The additives include myristic acid and dibutyl sebacate as plasticizers and butylated hydroxyanisole as an antioxidant. It was observed that the samples containing 70% PAC (PAC7) or 40% PAC (PAC4) with 30% additives had the highest antimicrobial activities against various microbial cells and no cytotoxicity regarding in vitro fibrob...

Research paper thumbnail of Biodegradation of inhibitory aromatic solvents in a novel bioreactor = 새로운 생물반응기를 이용한 독성방향족 용매의 생물학적 분해

Research paper thumbnail of Biodegradation of Toluene using Biofilms in a Bubble Column Bioreactor

Biodegradation of toluene in liquid effluent stream was carried out using biofilms of Pseudomonas... more Biodegradation of toluene in liquid effluent stream was carried out using biofilms of Pseudomonas putida formed on celite particles in the bubble column bioreactor. Silicon rubber tubing was installed at the bottom of the bioreactor and liquid toluene was circulated within the tubing. Toluene diffused out of the tube wall and was transferred into the culture broth where degradation by biofilms occurred. The operating variables affecting the formation of biofihns on celite particles were investigated in the bubble column bioreactor, and it was found that formation of bifilm is favored by high dilution rate and supply rate of carbon source which stimulate the growth of initially attached cells. Continuous biodegradation of toluene using biofilms was stablely conducted in the bioreactor for more than one month without any significant fluctuation, showing a removal efficiency higher than 95% at the toluene transfer rate of 1.2 g/L/h.

Research paper thumbnail of Pseudomonas SP, HN-72 and Purification Method of 2,6-NAPHTHALENE Dicarboxylic Acid Using the Same

Research paper thumbnail of A novel bioreactor for the biodegradation of inhibitory aromatic solvents: Experimental results and mathematical analysis

Biotechnology and Bioengineering, 1992

A novel bioreactor for the biodegradation of toxic aromatic solvents, such as benzene, toluene, a... more A novel bioreactor for the biodegradation of toxic aromatic solvents, such as benzene, toluene, and xylenes in liquid effluent stream, was developed. Silicon tubing was immersed in the completely mixed and aerated bioreactor, and liquid toluene as a model solvent was circulated within the tubing. Toluene diffused out of the tube wall and was transferred at high rate into the culture broth, where biodegradation occurred. The effect of operating parameters on the toluene transfer rate was investigated. During continuous operation, the biodegradation rate was considerably higher than those obtained using conventional methods. A mathematical model was established for continuous biodegradation, and simulation results coincided with the experimental results. The performance and operational criteria of the bioreactor were analyzed on the basis of both the experimental and simulation results. © 1992 John Wiley & Sons, Inc.

Research paper thumbnail of A novel biotransformation of 2-formyl-6-naphthoic acid to 2,6-naphthalene dicarboxylic acid by Pseudomonas sp. for the purification of crude 2,6-naphthalene dicarboxylic acid

Biotechnology Letters, 2008

Crude 2,6-naphthalene dicarboxylic acid was purified by Pseudomonas sp. HN-72 which biotransforme... more Crude 2,6-naphthalene dicarboxylic acid was purified by Pseudomonas sp. HN-72 which biotransformed the major impurity of 2-formyl-6-naphthoic acid into 2,6-naphthalene dicarboxylic acid. The biotransformation yield reached 100% when the reaction was performed at 40°C for 1 h, in 200 ml KH2PO4/KOH buffer (50 mM, pH 8.0), with 0.2% (w/v) crude 2,6-naphthalene dicarboxylic acid and 2.5 mg dry cell wt/ml.

Research paper thumbnail of A novel method to supply the inhibitory aromatic compounds in aerobic biodegradation process

Biotechnology Techniques, 1992

To efficiently supply inhibitory aromatic solvents such as benzene, toluene, and xylenes in liqui... more To efficiently supply inhibitory aromatic solvents such as benzene, toluene, and xylenes in liquid phase for aerobic biodegradation processes, a novel technique was developed. Silicon tubing was immersed in the bioreactor and liquid solvent was circulated within the tubing from a solvent reservoir. Transfer rate of the solvent through a silicon tubing was significantly affected by impeller speed, whereas other operating parameters such as aeration rate and circulation rate of liquid solvent within the tubing showed a negligible effect. Aerobic biodegradation of toluene and p-xylene was carried out using this method and the biodegradation rate of solvent mixture was high compared to those of conventional methods.

Research paper thumbnail of Simultaneous biodegradation of toluene and p-xylene in a novel bioreactor: experimental results and mathematical analysis

Biotechnology Progress, 1993

Simultaneous biodegradation of toluene and p-xylene was performed in a novel bioreactor, and the ... more Simultaneous biodegradation of toluene and p-xylene was performed in a novel bioreactor, and the performance was analyzed on the basis of both experimental and mathematical simulation results. The novel bioreactor employed a silicon tubing as a supplier of the aromatic solvents to be treated, and the transfer rate of toluene and p-xylene into the culture broth was easily controlled. Batch, sequencing batch, and continuous mode of operation were carried out in the novel bioreactor to compare the performance of the biodegradation of solvent mixture. Sequencing batch operation worked well, but several operational difficulties were found. Continuous operation was shown to present higher biodegradation rates and operational stability. The continuous biodegradation process was mathematically simulated, and operational conditions were optimized on the basis of the simulation results.