• Journal of Microbiology and Biotechnology
• /
• v.4 no.3
• /
• pp.210-214
• /
• 1994

The molecular weight of poly-hydroxybutyric acid (PHB) produced by Alcaligenes sp. K-912 is an important parameter characterizing the physical properties of the polymer. The effects of temperature and the levels of glucose, ammonium, phosphate and amino acids on the molecular weight of PHB were investigated. Molecular weight of PHB by temperature varied in the range of 380,000 to 550,000, 400,000 to 600,000 by glucose, 300,000 to 380,000 by phosphate, 400,000 to 1,000,000 by amino acids, respectively under the experimental conditions.

• Applied Biological Chemistry
• /
• v.32 no.3
• /
• pp.303-308
• /
• 1989

A bacterium synthesizing extracellular polysaccharide was isolated from soil and identified as Enterobacter agglomerans. The polysaccharide was found to be glucan polymer containing glucose and galactose in a molar ratio of 1 : 1.1. The aqueous solution was very viscous. The viscosity of 1% solution was 264 mPa.s. at $42\;sec^{-1}$ and yield stress was 4.89 Pa. The polysaccharide solution did not have thermal stability but pH and salt stability.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.05b
• /
• pp.316-319
• /
• 2000

In the case of immobilizing of glucose oxidase into polypyrrole (PPy) using electrosynthesis, the glucose oxidase (GOx) forms a coordinate bond with the polymer's backbone. However, because of intrinsic insulation and net-chain of the enzyme, the charge transfer and mass transport are obstructed during the film growth. Therefore, the film growth is dull. We synthesized the enzyme electrode by electropolymerization added some organic solvent, A formative seeds of film growth is delayed by adding the solvent. The delay is induced by radical transfer between the solvent and pyrrole monomer. In the case of adding ethanol, the radical transfer shares the contribution of dopant between electrolyte anion and GOx polyanion. This may lead to increase amount of immobilized the enzyme in ppy. However, adding tetrahydrofuran (THF), the radical transfer is more brisk, resulting in short chained polymer. Therefore, the doping level is lowered and then amount of immobilized of enzyme is decreased. For the UV absorption spectra of synthetic solution before synthesis and after, in the case of ethanol added, the optical density was slightly decreased for the GOx peaks. It suggests amount of GOx in the solution was decreased and amount of GOx in the film was increased. We established qualitatively that amount of immobilization can be improved by adding a little ethanol in the synthetic solution. It is due to radical transfer reaction. The radical transfer shares the contribution of dopant between small and fast electrolyte anion and big and slow GOx polyanion.

• Mycobiology
• /
• v.37 no.2
• /
• pp.89-93
• /
• 2009

The effect of fermentation parameters and medium composition on the simultaneous mycelial growth and exo-polymer production from submerged cultures of Ganoderma applanatum was investigated in shake-flask cultures. The optimum initial pH for mycelial growth and exo-polymer production was 5.0 and 6.0, respectively. The optimum temperature was $25^{\circ}C$ and the optimum inoculum content was 3.0% (v/v). The optimal carbon and nitrogen sources were glucose and corn steep powder, respectively. After 12 days fermentation under these conditions, the highest mycelial growth was 18.0 g/l and the highest exo-polymer production was 3.9 g/l.

• Journal of Pharmaceutical Investigation
• /
• v.16 no.3
• /
• pp.89-100
• /
• 1986

Although insulin has been available for the treatment of diabetes mellitus for more than half a centry, the deficiency of conventional insulin therapy for diabetic patients have, to this date, not been satisfactorily overcome by any method. The development of potential delivery systems for insulin is highly important to prevent excessive fluctuation of plasma glucose levels, which results in long term complications in the diabetic. There are three major approaches toward development of glucose responding insulin delivery systems: A bioengineering approach is to devise mechanical components capable of releasing insulin in amounts appropriate to varying blood-glucose requirements. A biological approach relies upon cultured, living pancreatic beta cells encapsulated to constitute an insulin delivery unit. A biochemical approach is to synthesize a stable and biologically active glycosylated insulin that is complementary to the binding sites of lectin. This paper will cover several specific areas, including pancreatic transplantation(total or isolated islet cells), artificial pancreases(bioengineering or biological approach), controlled delivery system, glucose sensitive membrane systems, and a self-regulating insulin delivery system.

• Journal of the Korean Applied Science and Technology
• /
• v.36 no.1
• /
• pp.269-278
• /
• 2019

We fabricated glucose oxidase (GOx)-modified biosensor for detection of glucose by physical immobilization of GOx after electrochemical polymerization of the conductive mixture monomers of the 3-thiophenecarboxylic acid (TCA) and thiophene (Th) onto ITO electrode in this study. We confirmed the successfully fabrication of GOx-modified biosensor via FT-IR spectroscopy, SEM, contact angle, and cyclic voltammetry. The fabricated biosensor has the detection limit of $0.1{\mu}M$, the linearity of 0.001-27 mM, and sensitivity of $38.75mAM^{-1}cm^{-2}$, respectively. The fabricated biosensor exhibits high interference effects to dopamine, ascorbic acid, and L-cysteine, respectively. From these results, the fabricated GOx-modified biosensor with long linearity and high sensitivity could be used as glucose sensor in human blood sample.

• Proceedings of the Korea Environmental Mutagen Society Conference
• /
• 2003.10a
• /
• pp.163-163
• /
• 2003

• Proceedings of the Korean Society of Toxicology Conference
• /
• 2003.10b
• /
• pp.163-163
• /
• 2003

Difficulties of long-tenn survival of lung cancer patients treated with conventional therapies require the need for novel approaches and gene therapy holds promise in this area. Several genes are known to have anti-tumor activities and have been used as a gene of delivery, however, a number of problems such as efficiency, specificity of the gene delivery hinder the application of gene therapy.(omitted)

• Journal of Sensor Science and Technology
• /
• v.4 no.4
• /
• pp.23-28
• /
• 1995

The ISFET glucose and sucrose sensors containing platinum electrode and photopolymeric enzyme membrane were fabricated. The platinum working electrode was used for the electrolysis of hydrogen peroxide, which was the other product of the enzyme reaction, to improve sensing characteristics of the sensors. In order to improve response time, photo-crosslinkable polymer(PVA-SbQ) was used to the matrix for the enzyme immobilized membrane. The characteristics of glucose and sucrose sensors were investigated according to the variation of platinum electrode area. The response time was about $3{\sim}5$ minutes and determinations of glucose and sucrose in the range of about $30{\sim}300mg/dl$ could be possible.

• Microbiology and Biotechnology Letters
• /
• v.22 no.4
• /
• pp.401-406
• /
• 1994

The medium compositions of Alcaligenes eutrophus were optimized for increasing PHB productivity. It is very important to optimize the concentrations of inorganic salts and trace eleme- nts as well as carbon and nitrogen sources to maximize cell growth rate and productivity. The fed-batch culture of Alcaligenes eutrophus by dual feeding of ammonia water and glucose under optimized initial medium concentrations was carried out. Glucose was fed manually according to glucose consumption rate and ammonia water by pH-stat. The final cell concentrations and PHB content in 30 hours were 122 g/l and 65% of dry cell weight(yielding 79 g of PHB/l), respectively and 2.64 g/l/hr of PHB production rate was obtained.