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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Korean Society for Biotechnology and Bioengineering
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Volume 5, Issue 4 - Dec 1990
Volume 5, Issue 3 - Nov 1990
Volume 5, Issue 2 - Aug 1990
Volume 5, Issue 1 - Mar 1990
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Extracellular Production of Alpha-Interferon by Recombinant Escherichia coli: Part II. The Growth Behavior of the Recombinant Cells
KSBB Journal, volume 5, issue 3, 1990, Pages 195~200
The growth behavior of recombinant Escherichia coli cells having plasmid pIF-III-B, which carries human alpha-interferon gene under the control of lpp promoter, lac promoter and lac operator, was studied by using of various E. coli host strains. Expression of the alpha-IFN gene is controllable by using inducer IPTG because the plasmid also contains lacI gene which produces lac regressors. The repressors block the transcription of alpha-IFN gene. There were considerable differences in cell growth according to the host strains used. Cell growth was inhibited not only by plasmid pIF-III-B itself but also by the induction of alph-a-IFN gene expression. Growth inhibition caused by the plasmid itself was more serious than that caused by the induction of alpha-IFN gene expression.
Study on Steroid Acly Transferase in the Rat Brain
KSBB Journal, volume 5, issue 3, 1990, Pages 201~205
The characteristics of steroid acyl transferase were studied in the rat brain with (4-14C)-dehydroepiandrosterone(DHEA). The results could be summarized as followings: The enzyme system responsible for the biosynthesis was localized at the microsome fraction. The optimum pH of this enzyme was 4.6 When DHEA was utilized as substrate,
5-pregnenolone was proved to be a competitive inhibitor. However testosterone was a noncompetitive inhibitor. The acylation at 3
-hydroxyl group was favored when the hydrophilicity at Cl7 position increased. However, this acylation at C3 was very low when A ring was aromatic. The acylation at Cl7 hydroxyl group reguired an absolute 17
Basic Studies on Cultivation of Transformed Plant Tissue in Bioreactor
KSBB Journal, volume 5, issue 3, 1990, Pages 207~214
Growth properties of carrot hairy roots transformed by Agrobacterium rhizogenes were compared in flask and bioreactor. Oxygen transfer coefficient KLa was measured during the cultivation in bioreactor. In flask cultures, initially sucrose 30g/l was nearly exhausted after 20days. pH was dropped from initially 5.8 to 4.79 after 4 days, but it is stable after that time. Finally, after 28 days, hairy roots were grown about twelve times. In view of the results studied optimum conditions, hairy roots were maintained high growth rates in sucrose 50g/l, pH 5.8, total nitrogen 60mM. Also in bioreactor cultures, fixed stainless sieve in bottom and aerated 0.31 vvm, the results of cultivation by the use of sucrose 50g/l had grown about twenty-eight times and pH variations were liked in flask. As a results, growth rate of 1.756g fresh weight/day/g inoculum in bioreactor were higher about three times than 0.57g fresh weight/day/g inoculum in flask culture. KLa values were showed a tendency to decrease from 0.209 min-1 to 0.068 min-1.
Protein Solubilization in Reverse Micelles of Cationic Surfactant
KSBB Journal, volume 5, issue 3, 1990, Pages 215~221
The solubilization of BSA, pepsin, trypsin and ribonuclease-a in cationic reverse micellar solutions has been investigated. For complete solubilization into reverse micellar solutions, pH values of several pH units above the isoelectric point of each protein were required. Solubilization was observed to decrease with increasing ionic strength of KCI. The size of empty micelles showed no significant change with increasing ionic strength. Trioctylmethyl ammonium chloride (TOMAC) in cyolohexane showed the lowest solubilization for the proteins. The system didodecyl dimethyl ammonium bromide (DDAB)-tetrachloroethylene was capable of solubilizing larger amounts of proteins than the system DDAB-benzene. Cetyl trimethyl ammonium bromide(CTAB)-hexanol-isooctane system showed lower solubilization than DDAB-tetrachloroethylene system, while it had higher Wo value.
Continuous Production of Sorbitol with Permeabilized Zymomonas mobilis Immobilized in Alginate and Chitin
KSBB Journal, volume 5, issue 3, 1990, Pages 223~227
This study describes the sorbitol production with permeabilized cells of Zymomonas mobilis immobilized in Ca-alginate. Toluene treated cells lose glucose-fructose oxidoreductase activity due to leaking of enzyme from the cells. In order to prevent this leakage, the permeabilized cells were immobilized in alginate and chitin. No significant loss of enzyme activity was apparent during 210h operation in a continuous process. The productivity of the continuous process was estimated to be about 3.5g/l -h for sorbitol at dilution rate
Protoplast Isolation and Reversion from Agrocybe cylindracea
KSBB Journal, volume 5, issue 3, 1990, Pages 229~234
The isolation and regeneration of protoplasts are necessary for protoplast fusion of edible mushrooms. In this study, over 5
107 ml-1 protoplasts of Agrocybe cylindracea were isolated using the method described by Yanagi. Enzyme mixture of cellulase Onozuka R10(2%), chitinase (0.2%) and Novozym 234(0.1%) was most effective for the isolation of protoplasts and the yield of protoplasts was 4.85
107 ml-1. 0.6M sucrose was the most effective osmotic stabilizer. The maximum amount of mycelia and yield of protoplasts were obtained from 5~7 days cultured mycelia. In the case of 5~7% days cultured mycelia, the digestion time with lytic enzyme was 4~6 hours. ACM and MCM medium were most effective for the regeneration and reversion of protoplasts, and reversion frequency was 6.9~7.0%. 0.6M sucrose was most stable osmotic stabilizer.
Production Of Gellan Gum by Pseudomonas elodea (I) -Estimation of Metabolic Parameters and Rheological Properties of Culture Broth-
KSBB Journal, volume 5, issue 3, 1990, Pages 235~240
A quantitative physiological approach has been employed to estimate the metabolic parameters such as specific uptake rates of nutrients and specific production rate in continuous culture of Pseudomonas elodea for gellan gum production. The estimated values of metabolic parameters are used for process improvement. During the exponential growth phase, the specific growth rate was 0.16hr-1 in batch culture. The gellan gum concentration increased up to 0.7g dry weight/100g broth and the apparent viscosity of the culture broth was about 4,500 cp.(72hrs culture). The ratio of specific uptake rate of carbon to that of nitrogen were found to be optimum at about 3.0mg-carbon/mg-nitro-gen. With the improved medium, the maximum gellan production rate, 0.6g dry weight/1/hr, was obtained at D=0.14 hr-1. The shear stresses of culture broth were fairly well correlated with shear rates by using Casson equation and at highly viscous culture broth, oxygen transfer coefficient was greatly reduced.
Immobilization of ATP on Bovine
- Caseins by Using Transglutaminase
KSBB Journal, volume 5, issue 3, 1990, Pages 241~246
ATP analogs were immobilized or bovine caseins by the action of transglutaminase. The ATP analogs immobilized on the caseins were enzymatically active and interconverten by kinases. The immobilized ATP was dephosphorylated to the corresponding ADP by hexokinase and rephosphorylated to the ATP in solid form by acetate kinase. Under the conditions chosen, about 55% of the immobilized ATP was dephosphorylated and about 80% of the resulted ADP was rephosphorylated. Bovine
-casein was more useful than
sf-casein as a carrier and C8-substituted ATP analognwas more effective than N6-substituted one in immobilization. Michaelis constant of C8-substituted ATP analog immobilized on
-casein was similar to that of free form of ATP and that of ATP analog. The immobilized ATP was much more stable than free ATP and its analog, while maximum velocity was reduced to 37% of the free ATP analog. The immobilized ATP was recovered almost completely by calcium precipitation.
Transformation of Carrot (Daucus carota) Cells Using Binary Vector System
KSBB Journal, volume 5, issue 3, 1990, Pages 247~253
These studies were carried out to obtain the transformant from carrot cells by using binary vector pGA472 with NPT II gene to confer kanamycin resistance in the plant cells. The binary vector pGA472 was mobilized from E. coli MC1000 into A. tumefaciens strains isolated in the Korea, C23-1. K29-1, and disarmed Ti-plasmid PC2760, and A28l using a tri-parental mating method with E. coli HB101/pRK2013. Transconjugants, C23-1/pGA472, K29-1/pGA472, PC2 760/pGA472 and A28l/pGA472 were obtaind on the minimum AB media containing tetracycline and kanamycin, were comfirmed to hold the Ti-plasmid and pGA472 binary vector on the 0.7% agarose gel. Transformed carrot calli were initiated on the MS media supplemented with l00
/ml kanamycin and 250
/ml carbenicillin after co-cultivation of carrot explant and transconjugant Agrobacteria. Selected callus was grown vigouousley for subculture on the medium containing 100
/ml kanamycin, thus indication that the selected callus was transformed with NPT II gene.
Protoplast Fusion of phaffia rhodozyma
KSBB Journal, volume 5, issue 3, 1990, Pages 255~261
Cell fusion between complementary mutants isolated from astaxanthin-producing yeast, Phaffia rhodozyma, was carried out to obtain astaxanthin-overproducing strains by protoplast fusion technique. The frequency of protoplast fusion was ranged from 2.3
10-5 to 6.0
10-5, and nuclear fusion in the cells of hybrids was demonstrated by several techniques such as isolation of recombinants after mitotic segregation of parental genetic markers, estimation of DNA content, direct observation of nuclei with nuclear staining, and comparison of survival rate to UV exposure. One of several hybrids, Fl, showed approximately 3-fold increase in astaxanthin content when compared with wild parent.
Ginsenoside Production by Hairy Root Cultures of Panax ginseng Transformed With Agrobacterium rhizogenes
KSBB Journal, volume 5, issue 3, 1990, Pages 263~268
New methods have been developed to transform Panax ginseng with Ri plasmids of Agrobacterium rhizogenes 15834 and A. rhizogenes A4. Modified leaf disc method was made feasible to establish hairy root culture even when an axonic plantlet was not available as in the case of P. ginseng. The contents of ginsenosides (Rgl, Rf, Rc, Rbl, and Rb2) in hairy roots. were determined by HPLC. Hairy root cultures, established as liquid culture in MS medium, was produced 0.34~1.19% ginsenosides on dry weight basis, and this result is significantly higher level than that of normal P. ginseng.
High Density Cultivation of Methylobacillus sp. SK1 in Fed-Batch System
KSBB Journal, volume 5, issue 3, 1990, Pages 269~277
Methylobacillus sp. SK1, an obligate methylotroph, was cultivated in a fed-batch culture using DO as a methanol feeding indicator with a micro computer-aided control system. While 2.07g/l of cell density was obtained after 13 hr in the batch culture (initial methanol concentration: 1.0%(v/v)),45.3g/l of cell density was obtained after 17 hr by feeding methanol and metal ions in the fed-batch culture with oxygen supply. The high-density biomass was obtained in short cultuivation time by fed-batch culture with feedback control, and consequently the biomass productivity was significantly increased. It was mainly due to extension of logarithmic growth period by methanol feeding without methanol inhibition and intensive aeration without DO limitation with microcomputer-aided control system.
-Glucosidase Immobilized on the Modified Chitin in Bioresctors
KSBB Journal, volume 5, issue 3, 1990, Pages 279~291
Partial hydrolysed and deacetylated chitin, CHITA and CHITB as supports of immobilized enzyme were obtained by treatment of acid and base respectively. Glutaraldehyde, bifunctional reagent, was employed for crosslinking between
-glucosidase and support. Immobilized enzyme activities of CHITA-Gase and CHITB-Gase were determined with the reaction of p-nitrophenol-
-D-glucopyranoside(PNG) in batch reactor, CSTR and PFR. Their optimum temperature, pH and enzymatic characteristics including Km and Vmax values were observed with variation of the flow rates. Mass transfer coefficient(h), effectiveness factor(η), deactivation rate(kd ) of two immobilized enzymes were also examined to compare efficiency of reactors.
Extracellular Production of Alpha-Interferon by Recombinant Escherichia coli: Part III. Gene Expression for Product Formation
KSBB Journal, volume 5, issue 3, 1990, Pages 293~298
Alpha-interferon was produced by using recombinant Escherichia coli strains, which carry cloned alpha-interferon gene in plasmid vectors, pIF-III-B and pIF-III-C. With the aid of signal sequence of E. coli lipoprotein, which is placed right in front of the upstream of the cloned alpha-interferon gene of the plasmids, about 50% of alpha-interferon produced was excreted or secreted. Meanwhile, there was no extracellular production of alpha-interferon from the recombinant strain carrying the plasmid Hif-2h that lacks the signal sequence of lipoprotein.
High Frequency Electroporation-Transformation System for Coryneform Bacteria
KSBB Journal, volume 5, issue 3, 1990, Pages 299~306
Escherkchla coli/Cownebacterium glutamicum shuttle vectors, pECCGl and pECCG2 were constructed by joining a 3.0 kb C. glutamicum cryptic plasmid pCBl and a 3.94 kb E. coli plasmid pACYC177. Using the plasmid pECCGl, various parameters involved in electroporation system including electric field strength, resistance, DNA concentration, cell concentration and growth stage were investigated independently and optimized for the high efficiency transformation of coryneform bacteria. Transformation efficiencies of 106 transformants/
of plasmid DNA were achieved with Corynebacterium glutamicum.
Microcomputer-aided Fermentation System for High Density Fed-Batch Cultivation
KSBB Journal, volume 5, issue 3, 1990, Pages 307~313
A microcomputer-aided fermentation system was constructed for high density fed-batch culture using dissolved oxygen(DO) as a substrate feeding indicator. DO signal was processed prior to aquisition to computer. Agitation speed and oxygen flow rate was changed stepwisely to maintain DO value at a constant level. Agitation speed was controlled by the output signal of D/A converter. Oxygen flow rate was controlled by a flow rate control valve connected to a stepping motor. Substrate was fed with a feeding pump operated by the abrupt increase of DO signal. Methylobacillus sp. SK1 was cultivated to test the system and 16.53g/l of cell density was obtained after 10 hr.