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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Microbiology and Biotechnology Letters
Journal Basic Information
Journal DOI :
The Korean Society for Applied Microbiology and Biotechnology
Editor in Chief :
Volume & Issues
Volume 20, Issue 6 - Dec 1992
Volume 20, Issue 5 - Oct 1992
Volume 20, Issue 4 - Aug 1992
Volume 20, Issue 3 - Jun 1992
Volume 20, Issue 2 - Apr 1992
Volume 20, Issue 1 - Feb 1992
Selecting the target year
Accumulation of Poly-
-Hydroxybutyrie Acid by Alcaligenes sp.
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 363~370
Microorganisms capable of accumulating poly-p-hydroxybutyric acid(PHB) were isolated from soil by enrichment culture technique. Among them, the strain designated as FL-027 had high PHB productivity and was identified as Alcaligenes. The optimal medium composition for cell growth was 8.0
of fructose and 3.0
, equivalent to C/N ratio 5.04 at pH 7.0 and
. To investigate the optimal conditions for the PHB accumulation, we divided the process into two stages; the first stage for the growth of the cell in nutrient-rich medium and the second stage for the PHB accumulation in nutrient-deficiency medium. The optimal conditions for PHB accumulation were 8.0
of fructose and 0.25
, equivalent to C/N ratio 60 at pH 6.5 and
. PHB accumulation was stimulated by deficiency of nutrients such as
in medium. Among them.
deficiency was chosen because of its effectiveness. We found the inhibition of cell growth by fructose in batch culture. In order to keep the fructose concentration at an optimal level, intermittent feeding fed-batch culture was employed, and the cell concentration as high as 10.83
whose PHB content was responsible for 43% of the dry cell weight. The purified PHB was identified as homopolymer of 3-hydroxybutyric acid by using IR and
Effect of pH on Growth and Cultural Characteristics of Bacillus sp. SH-8 and Bacillus sp. SH-8M
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 371~376
The growth and cultural characteristics of Bacillus sp. SH-8 and SH-8M were investigated at various pH conditions. Bacillus sp. SH-8 showed normal growth pattern above pH 9.0. However, with the pH adjusted below 7.7, 0.
decreased rapidly with concomitant reduction in viable cell numbers. In contrast, Bacillus sp. SH-8M demonstrated growth capability at pH 7.7, but with slightly reduced growth rate at pH 6.9. Similar results were obtained when those two strains were cultivated on the solid medium. Both of them showed short rod shapes at pH 10.2. However, at pH 7.7 only Bacillus sp. SH-8 was observed to have elongated rod shape. Extracellular pH of both the strains, when cultured at initial pH of 10.2, reached to 9.0 after the incubation of 28 hours. At the initial pH of 9.0 and 9.6, the extracellular pH was reduced at the beginning of cultivation, but elevated after 12 hours. When cultured at initial pH of 6.9 and 7.7, extracelluar pH of Bacillus sp. SH-8M increased to 8.0 and 8.7, respectively, while that of Bacillus sp. SH8 remained constant pH 7.0. The highest sporulation rate of Bacillus sp. SH-8 and SH-8M was obtained at the initial pH of 10.2 and after the incubation of 3 days with the sporulation rate of 95% and 85%, respectively.
Characterization of Bacillus thuringiensis Seven Isolates from Soil
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 377~383
Seven strains of Bacillus thuringiensis were isolated from soil in Korea and characterized. The isolates were named HL-8, 10, 12, 13, 14, 15 and 16 which produced parasporal crystals and endospores in their cells. The biochemical characteristics of the seven isolates were only minor different in specific chracteristics to the known serotypes of Bacillus thuringiensis. The number of the plasmid DNA elements from the isolates were studied. The computerized molecular weights of the six plasmid elements in the HL-8 and HL-lO strains were from 3.01 to 15.1 Md, four plasmid elements in the HL-12 were from 5.4 to 21.9 Md, four plasmid elements in HL-13 were from 5.1 to 20 Md, three plasmid elements in HL-15 were from 3.4 to 11.3 Md and three plasmid elements in the HL-16 were from 2.4 to 20.1 Md. The seven isolates showed resistances to ampicillin, bacitracin, cephalothin, methicillin and penicillin G. The strains of HL-8, HL-lO, HL12, HL-14, HL-15 and HL-16 showed lethalities against Culex pipiens 3rd instar larvae. The HL8 and 14 strains showed 100% lethality to the larvae within 48 hours. HL-13 strain did not have toxicity against the larvae.
Genetic Transformation of Biocontrol Agent Bacillus sp, YBL-7 by Plasmid pE194
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 384~389
Bacillus sp. YBL-7 which had been isolated from ginseng root-rot suppressive soil was able to antagonize Fusarium solani causing ginseng root-rot by their antibiotic substance. In order to develop multifunctional antagonist on Bacillus sp. YBL-7 as a biocontrol agent against Fusarium salam', optimal conditions for protoplast transformation system of Bacillus sp.YBL-7 by the vector plasmid pE194 were investigated. The protoplasts of Bacillus sp. YBL-7 were obtained at best efficiency by treatment with 200
/ml of lysozyme in the pH 7.0 of SMM buffer for 90 minutes at
. The cell wall of the protoplast was regenerated on the agar plate containing 1.2% agar and 0.7 M mannitol. Under the best condition for protoplast formation and regeneration, the optimal transformation was achieved with 40% polyethylene glycol (M.W. 4000) treatment for 10minutes. The vector plasmid pE194 showed the best transformation frequency at 5
g/ml of final concentration. The pE194 was very stable over 80% in the transformants.
Aflatoxin Degradation by an Enzyme from Aspergillus awamori var. fumeus
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 390~394
Some enzymatic characteristics of the aflatoxin degrading factor produced extraceIlularly by Aspergillus awamori var. fumeus were investigated. When aflatoxin B1 was incubated with the culture filtrate of A. awamori var. fumeus. 60% of it was degraded within an hour. The degradation rate decreased with time and there was virtually no degradation after one hour. The apparent Michaelis constant (
) determined by Lineweaver-Burk plot was
. The optimum degradation was observed at
and pH 5. For the degradation, molecular oxygen seemed to be required. The degradation was enhanced by the
. but was inhibited by many other ions like
, The presence of either KeN or metyrapone inhibited the reaction while that of
cytochrome C or NADPH showed no effect.
Studies on the Isolation of Cholesterol Oxidase Producing Soil Microorganism and the Culture Condition for the roduction of High Activity Cholesterol Oxidase
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 395~400
A novel strain of HSL613 producing a large amount of cholesterol oxidase as an extra~ cellular enzyme was isolated from soil samples. Experiments were carried out to optimize the condition of cholesterol oxidase production using HSL613 strain. This microorganism was shown to give the maximum yield f)f cholesterol oxidase in the medium containing 2% glucose, 2% yeast extract, 0.2%
, 0.1% NaCl. 0.005%
. The optimum temperature was
and the enzyme production reached a maximum level at 144 hours of cultivation (10.3
Purification and Characterization of Cholesterol Oxidase Produced by Soil Microorganism HSL613
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 401~408
The extracellular cholesterol oxidase produced from a soil microorganism HSL613 was purified and partially characterized. Through a series of purification procedures including concentration with CH2 concentrator, DEAE-cellulose column chromatography and gel filtration on Superose12, the purified enzyme was shown to have a specific activity of 108 units/mg protein giving 30.8-fold purification and final yield of 66%. The molecular weight of the enzyme was estimated to be 59,500 daltons by SDS-PAGE. The optimum temperature and pH for this enzyme were
and 6.0, respectively. The activity of the purified cholesterol oxidase was inhibited by
Production and Characteristics of Pullulanase from Bacillus cereus
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 409~416
The optimum cultural temperature and time for the pullulanase production by Bacillus cereus were
and 72 hrs, respectively. The addition of casein, nutrient broth and egg albumin to the basal medium, respectively, increased greatly the enzyme production. The enzyme was purified by ammonium sulfate fractionation, CM-cellulose and DEAE-cellulose column chromatographies. The specific activity of the purified enzyme was 29.09 U/mg protein and the yield of enzyme activity was 17.1% The purified enzyme showed a single band on polyacrylamide disc gel electrophoresis and its molecular weight was estimated to be 61,000 by SDSpolyacrylamide disc gel electrophoresis. The isoelectric point for the purified enzyme was pH 7.0. The optimum temperature and pH were
and 6.5. The purified enzyme was stable below
and in the pH range of 6.5-11.0. It was greatly inhibited by
, and its thermal stability was increased by the addition of
Among various substrates, pullulan was favorably hydrolyzed by the purified enzyme and the hydrolysis product 011 pulluIan was maltotriose.
Effects of Sucrose on Invertase Expression in Recombinant Saccharornyces cerevisiae
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 417~421
The expression pattern of the cloned SUC2 gene in recombinant Saccharomyces cerevisiae was investigated in a two-stage culture. The recombinant yeast grown in a glucose medium where the SUC2 gene was repressed was harvested and then resuspended in a sucrose medium to induce invertase expression. The maximum activity of 10 units was obtained in a medium containing 2
sucrose as a carbon source at
. The oscillatory behavior of invertase activity in response to glucose concentrations in the second stage was observed. This effect can be attributed to a series of events: invertase expression from the SUC2 gene. sucrose hydrolysis to glucose and fructose by invertase, SUC2 repression by high glucose concentration, invertase induction as a result of depletion of glucose used for the yeast growth. The invertase activity was increased by 72.5% when growth temperature changed from
Effect of Water-Activity Depressor on the Enzymatic Synthesis of Maltosyl-
-Cyclodextrin through the Reverse Reaction of Pullulanase
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 422~429
The effect of various water-activity depressors, such as pol yo Is, sugars, and polymers, on the conversion yields of the enzymatic synthesis of maltosyl-
-cyc1odextrin and maltose through reverse reaction of pullulanase was investigated. PEG 6000 of concentration of 10% (w/w) was found to be the most acceptable water-activity depressor resulting for increment of conversion yield from 43.0% to 55.9%, corresponding maltosyl-
-cyc1odextrin concentration of 3.02 g/100 ml H20. Water activity was changed from initial 0.966 to 0.914 upon addition of 20% (w/w) of PEG 6000. The conversion yields were inversely proportional to the water activities, and the increased conversion yield was caused by water activity depression which inhibited the hydrolysis reaction of maltosyl-
-CD to maltose and
-cyc1odextrin. The changes of enthalpy (
H), entropy (
S), and Gibbs free energy (
G) were calculated to be 36.788 kJ/mole, 0.067 kJ/mole K. and 14.433 kJ/mole, respectively. The synthesis of maltosyl-
-CD could be increased substantially by the intermittent feeding of
-cyclodextrin. PEG 6000 could be separated effectively from reaction mixture using ultrafiltration membrane for reutilization.
Hydrogen Evolution by Mixed Culture of Clostridia with Rhodopseudornonas sphaeroides
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 430~436
Hydrogen evolution by mixed fermentation of Clostn"dium butyn"cum and photosynthetic bacteria which were capable of consuming clostridial metabolites and evolving hydrogen was investigated. Acetate and butyrate formed from anaerobic clostridial fermentation were efficiently utilized by Rhodopseudomonas sPhaeroides K-7. For complete bioconversion of clostridial metabolites such as acetate and butyrate into hydrogen, mixed culture of both anaerobic organisms forming molecular hydrogen was performed. By the mixed culture, the yield of hydrogen production increased by 20 to 75% and the levels of clostridial metabolites such as acetate, butyrate decreased in the fermentation broth. Influence of cell mixing ratio. mixing time and inoculum level on hydrogen evolution by mixed culture were examined. And then cometabolic pattern compared with in pure culture was observed as time course.
An Innovative Process for High Fructose Corn Syrup Production Coupled with Direct Saccharification of Raw Corn Starch in a Bioattritor
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 437~444
An innovative process for high fructose corn syrup (HFCS) production coupled with direct saccharification of raw corn starch in the agitated bead enzyme reactor (bioattitor) was investigated. The required high concentration/purity of glucose solution suitable for isomerization was produced directly in a bioattritor. without condensation of hydrolyzate, 398 g glucose/
and 98% glucose content from 400 g/
(w/v) of raw corn starch after 24 hours. The unsaccharified residual starch could be separated easily upon centrifugation, and resaccharified. The obtained solution also possessed other desirable requirements as substrate for isomerization, such as. low concentrations of denatured protein and calcium ions, thereby, simplified the purification step. The obtained glucose solution was isomerized in an enzyme reactor paked with immobilized glucose isomerase to evaluate the suitability as a substrate. The proposed new HFCS process seems to have many advantages over the conventional process via liquefaction-saccharification steps. The follow-up investigations of the proposed process need to be conducted to evaluate the feasibility of industrial application.
Oxygen Transfer in Animal Cell Culture by Using a Silicone Tube as an Oxygenator
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 445~450
An enhancement of the oxygen transfer rate in a 1
bioreactor for mammalian cell culture by using a silicone rubber tubing as an oxygenator was investigated. When the silicone membrane was used to supply oxygen to the culture broth, the oxygen transfer coefficients (
) measured in deionized-distilled water were markedly increased. Effect of surface aeration without the tubing aeration was very low under
. The enhancing effects of agitation rates on
were much more effective than those of aeration rates. The increase of
with increasing tube length was observed as a result of the large surface area for oxygen supply. However, 2 m of the tube length was adequate for a 1
vessel. The larger blade type of impeller was effective to enhance the kLa values because of its high mixing intensity. In culture medium supplemented with 5% serum, kLa values were reduced to approximately 40% probably due to the viscosity. We also obtained the normal cell concentration of
of HepG2 on microcarriers, which could be achieved in a typical bioreactor for animal cell culture.
Modeling and Characteristics of Ethanol Fermentation Process Combined with Pervaporation
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 451~458
Pervaporation which is capable of removing ethanol selectively was adopted to reduce the ethanol inhibition and in situ recovery of ethanol in ethanol fermentation, The composite membrane made of silicone and polysulfone was used to separate the ethanol selectively. The ethanol selectivity of the membrane was about 4 and the total flux was 300 g/m2 h at 301:: and 10 mmHg for 25 g/l of feed concentration. Saccharomyces cerevisiae entrapped within Ca-alginate gels was employed for ethanol fermentations in a fluidized-bed bioreactor. The pervaporation membrane unit and fluidized-bed bioreactor were combined into one system. The proposed model equations for the combined system showed good accordances with the experimental results. It was found from the simulation results that the ethanol concentration in the broth for the combined system was lower than that for the continuous fermentation system without a membrane unit. Ethanol productivity can be thus increased by employing the combined system.
Cell Immobilization of Zyrnornonas rnobilis by Entrapment
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 459~469
The immobilization characteristics of Zymomonas mobilis for ethanol production were examined. Four different strains of Zymomonas mobilis have been used for ethanol production. Among those, Zymomonas mobilis KCTC 1534 has been selected as the best strain for the highest ethanol productivity from glucose and sucrose. The optimum temperature and pH of the selected strain for ethanol production were
and 5.0 respectively for both free and immobilized cells. When the cells were immobilized by the gel entrapment method, the immobilized cells could produce ethanol at a little higher temperature than free cells. Calcium alginate was selected as the best gel for immobilizing cells. The immobilized cells could maintain the viability of 80% in 10 weeks storage at
in the medium with 2% calcium chloride. 20-25 hours of preincubation in 10% glucose solution was required for the activation of immobilized cells entrapped within calcium alginate gel.
Effects of Lyophilization on Starter Cell of Rifamycin Fermentation
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 470~476
Upon lyophilization of Nocardia mediterranei, the effects of cryoprotectants, cell concentration and drying time on viability were examined, The data were treated by computer according to response surface analysis. As a result, the maximum value of presumed viability was 39.3% under the optimal conditions of 1l.6%(v/v) sucrose,
(CFU/ml) cell concentration, and drying time for 6.18 hrs. We also used the starter cell of rehydrated solution after lyophilization in industrial production, obtained the fermentation pattern and the purity of rifamycin B which were the same with control (FVM) and it is possible for us to use N mediterranei as a starter cell after the storage of lyophilization for 18 months.v
Degradation of Fats, Oils and Hydrocarbons by Acinetobacter calcoaceticus
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 477~482
A bacterial strain Acinetobacter calcoaceticus was examined for its ability to degrade fats, oils and hydrocarbons, and tested for the possibility of application in wastewater treatment. All fats and oils tested were degraded by the strain. About 60% of hexadecane, 26% of fish oiL and 40-54% of vegetable oils were consumed respectively in shaking-flask culture. Saturated fatty acid compositions were about 55% in fish oil and 6-12% in vegetable oils. Increases in cell mass were accompanied with decreases in the concentrations of carbon sources. When jar fermentor in place of shaking-flask was used as a culturing vessel. above 80% of all carbon sources was consumed and yield of cell mass was improved to nearly 1.00. Synthetic wastewaters containing 3% of fat, oil, or hydrocarbon as a sale ca,bon source were treated sequentially with A. calcoaceticus first and then exposed to activated sludge. The concentrations of carbon sources were decreased below 0.06% through the process, and the concentrations of suspended solids were lower than 53 mglml. The data imply the potential use of A. calcoaceticus in wastewater treatment.
Tracking of the
Gene in Conjugal Transfer by Using DNA Probe
Microbiology and Biotechnology Letters, volume 20, issue 4, 1992, Pages 483~490
In order to understand the transfer behavior of a particular gene in water environments, kanamycin resistance (
) gene was tracked by Southern hybridization with DNA probe in its conjugal transfer. A
natural bacterial isolate and genetically modified microorganisms (GMMs) constructed from the isolate were used as donor for conjugal transfer of the
gene. The transfer frequencies of the
gene from GMM strains were generally 10 to 100 times higher than those from the natural isolate. The conjugants obtained from GMM strains in LB broth had more plasmids newly appeared, and particularly the conjugants in A Wand FW waters revealed more rearrangement in their plasmids as a function of conjugation time. When plasmids of the conjugants obtained in LB broth were Southern hybridized with DNA probe of the
plasmids in the conjugants were detected at the same position of the plasmids in donor cells, in spite of the fact that the plasmids were highly rearranged in conjugant cells. But the
plasmids in the donor of DKI and DKC601, and DKC600 were not identified in the conjugants obtained after 50 h conjugation in AW and after 30 h in AW, respectively. The size of the
plasmids showing hybridization signal were a little changed in the conjugants obtained in A Wand FW waters. Therefore, the method of Southern hybridization with DNA probe was proved to be very specific and useful for tracking of particular genes in water environments.