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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
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Volume & Issues
Volume 26, Issue 6 - Dec 1998
Volume 26, Issue 5 - Oct 1998
Volume 26, Issue 4 - Aug 1998
Volume 26, Issue 3 - Jun 1998
Volume 26, Issue 2 - Apr 1998
Volume 26, Issue 1 - Feb 1998
Selecting the target year
Fixation by Chlorella HA-1 Cultured in Bubble Columns.
Microbiology and Biotechnology Letters, volume 26, issue 1, 1998, Pages 1~6
The characteristics of
fixation by Chlorella HA-1 cultured in bubble columns were studied to achieve high photosynthetic rates per basal area. The influence of experimental conditions such as the diameter of a bubble column and gas flow rate, on photosynthesis of Chlorella HA-1 was investigated. The maximum productivity and the overall
fixation rate obtained in a 0.15 L bubble column was 1.09 g dry biomassa-day and 1048 g CO
-day, respectively. Light limitation has been observed in the bubble columns having a diameter larger than 3.5 cm.. As the reactor volume increased, the decrease of the
fixation rate was remarkable. High gas flow rate was helpful to mitigate the light limitation problem.
Changes of Oxidative Enzymes and Fatty Acid Composition of Bifidobacterium adolescentis and B. longum under Anaerobic and Aerated Conditions.
Microbiology and Biotechnology Letters, volume 26, issue 1, 1998, Pages 7~14
To study the oxygen tolerance mechanism of bifidobacteria, we have studied the growth of cells, the activities of the enzymes which were related with oxygen, such as catalase, superoxide dismutase(SOD), NADH oxidase, and NADH peroxidase, and cellular fatty acid compositions of Bifidobacterium adolescentis and B. longum under anaerobic and aerated (microaerobic and aerobic) conditions. B. longum grew relatively well under the microaerobic conditions, whereas the growth of B. adolescentis was inhibited under the same aerated conditions. B. adolescentis had extremely low level of NADH oxidative enzymes while B. longum had the relatively high level of NADH oxidative enzymes, whose activities were dramatically increased from 3.7 to 11.4 times by microaerobic condition but not in B. adolescentis. The activity of SOD was unexpectedly high in B. adolescentis compared with in B. longum under anaerobic and aerated conditions. The activities of catalase were not detected in all samples tested in this study. We also found that normal
were the major fatty acids in B. adolescentis and B. longum under anaerobic and aerated conditions. 2.2-14.1%
cyclo fatty acid was detected only in B. longum and the fatty acid was increased by the addition of the aeration. The
cyclic fatty acid was identified as a cis 9, 10-methylene octadecanoic acid, which was different from lactobacillic acid in the cyclized site. 6.6%-24.6% of dimethyl acetals (DMA) which came from plasmalogen were observed in the B. adolescentis and B. longum grown under anaerobic condition, and the components were notably decreased in the cells grown under the aerated conditions. It is believed that NADH oxidative enzymes play an important role to detoxify oxygen metabolites of Bifidobacteriurn spp. under anaerobic and microaerobic conditions. Independently from oxidative enzymes, it seems that oxygen stress may induce the change of the level of cellular fatty acids showing an increase of
cyclo in B. longum and a decrease of
of plasmalogen in B. longum and B. adolescentis to adapt in environment.
Condition Optimization for Overexpression of the Aklavinone 11-Hydroxylase Gene from Streptomyces peucetius subsp. caesius ATCC 27952 in Escherichia coli.
Microbiology and Biotechnology Letters, volume 26, issue 1, 1998, Pages 15~22
The dnrF gene, responsible for conversion of aklavinone to
-rhodomycinone via C-11 hydroxylation, was mapped in the daunorubicin gene cluster of Streptomyces peucetius subsp. caesius ATCC 27952, close to drrAB, one of the anthracycline resistance genes. To characterize the enzymatic properties of the aklavinone 11-hydroxylase, the dnrF gene was overexpressed in Escherchia coli. The pET-22(+) plasmid which has the T7 promoter under the control of lacUV5 gene was used for the overexpression of the dnrF gene, and the recombinant plasmid pET213 that contains the dnrF gene linked to the T7 promoter of pET-22b(+) was introduced into the E. coli BL2l. When the expression of the dnrF gene was induced by IPTG at the final concentration of 1 mM, the induced protein could be detected in SDS-PAGE only in insoluble precipitate. The insoluble protein was electroeluted from the gel and used for the preparation of antiserum in mice. Various culture conditions were tested to maximize the expression of the aklavinone 11-hydroxylase in soluble form. The enzymatic activity was checked by the bioconversion experiment, and the protein was confirmed by the SDS-PAGE and the Western blot analysis. From the analysis of the data, it was concluded that the culture induced with IPTG at the final concentration of 0.02 mM at 37
yielded the best productivity of active form of enzyme.
The Bacillus subtilis Genome Sequencing Project in Korea: Sequence Analysis of the 53 kb DNA Fragment at 180
- of B. subtilis 168 Chromosome
Microbiology and Biotechnology Letters, volume 26, issue 1, 1998, Pages 23~33
The entire sequence of a 4,214,810 bp genome of the Bacillus subtilis 168 has been determined by an international project, and the completion has been announced on July 19, 1997. For the sequencing project an international consortium was established and 25 European, 7 Japanese laboratories, 2 biotechnology companies, and our laboratory participated in the project. Within this framework we determined the complete nucleotide sequence of a 53,289 bp fragment upstream of the odhA gene (181
) of the B. subtilis 168 chromosome. On the basis of the published DNA sequences of the B. subtilis sspC and odhA genes, we obtained genomic fragments by plasmid rescue and long-range PCR. The sequenced fragment contains 56 putative open reading frames (designated yojA-yolI and 9 known genes (sspC, cge cluster, orfE5, orfRMl and odhA), in which we found many interesting features. In addition, the entire nucleotide sequence of a 53,289 bp region enabled us to revise the current genetic map of this region.
Increased Expression of a Chemically Synthesized Human Lysozyme Gene in Saccharomyces cerevisiae
Microbiology and Biotechnology Letters, volume 26, issue 1, 1998, Pages 34~39
We have already prepared a human lysozyme (HLY) structural gene from chemically synthesized 38 oligomers with high codon usage in Saccharomyces cerevisiae. For directing the synthesis and secretion of HLY in S. cerevisiae, two types of expression vectors, a YCp centromere-based vector, pHK101 and a YEp 2-
circle-based vector, pHK501 were constructed. With the resulting plasmids, we have confirmed that yeast transformant harboring pHK501 has more secreted HLY than pHK101-transformant by using a lysoplate and a turbidimetric assay. In flask cultivation, pHK501-transformant produced active HLY about 8 times (55 units/
) higher than pHK101-transformant. From batch cultivation, the HLY productivity was obtained with 1.12 units/
/h, corresponding to a 1.8-fold increase compared with flask fermentation. These results indicate that yeast transformant with pHK501 vector overexpressed and secreted HLY than that of YCp type vector.
-Galactosidase with High Transgalactosylation Activity Produced by Penicillium sp. KFCC 10888.
Microbiology and Biotechnology Letters, volume 26, issue 1, 1998, Pages 40~44
A Penicillium strain which produces
-galactosidase with high transgalactosylation activity, was isolated from soil and registered as Penicillium sp, KFCC 10888. When
-galactosidase from Penicillium sp. KFCC 10855 reacted with 40% lactose, transgalactosylation ratio reached up to 70% at the 73% conversion of initial lactose. The biosynthesis of the enzyme in Penicillium sp. KFCC 10888 was not induced by lactose. The soybean meal was an effective component of the culture medium. The optimum pH and temperature for transgalactosylation were 4.0 and 55
, respectively. The production of galactooligosaccharides was in proportion to the initial lactose concentration. When the enzyme reacted with 40% lactose (pH 4.0) at 55
, the concentration of galactooligosaccharides increased up to 40% of total solid concentration.
L-Leucine Production using Amino Acid Analogues-resistant Mutants of Corynebacterium glutamicum
Microbiology and Biotechnology Letters, volume 26, issue 1, 1998, Pages 45~49
Two kinds of Mutants of Corynebacterium glutamicum, which were resistant to branched chain amino acid analogues, were obtained for L-leucine production; C. glutamicum LT26 resistant to 4-azaleucine and
-hydroxyvaleric acid, and from which C. glutamicum LT3811-70 resistant to DL-4-thiaisoleucine were derived. Accumulation of L-leucine in the culture broths of these mutant strains, C. glutamicum LT26 and LT3811-70, were much higher than those of their parent strains even though they were non-auxotrophic mutants. Enzymatic analyses were performed to measure the activities of
-acetohydroxy acid synthase (AHAS) and
-isopropylmalate synthase (IPMS), which were the key enzymes for the L-isoleucine, L-valine and L-leucine biosynthetic pathways branching from a common precursor. In C. glutamicum LT26 and LT3811-70, AHAS and IPMS were found to be derepressed and desensitized to L-leucine. In addition, in C. glutamicum LT3811-70, IPMS was further more derepressed by L-leucine and AHAS was more desensitized by L-isoleucine and L-valine compared to its parent strain, C. gIEitamicum LT26.
Effect of Esterases from Rice Wine Yeast on the Ethyl Caproate Production during Rice Wine Brewing.
Microbiology and Biotechnology Letters, volume 26, issue 1, 1998, Pages 50~54
Ethyl caproate is one of the important flavor compounds produced during the brewing of rice wine. The rice wine yeast and koji were reported to produce the esterases which synthesize and also hydrolyze ethyl caproate. From the results of monitoring the esterase activities of rice wine yeast and koji, their roles for producing ethyl caproate during brewing were postulated. In case of rice wine yeast, the production of esterase synthesizing ethyl caproate was influenced by the substrate, caproate but that of esterase hydrolyzing ethyl caproate was promoted by ethyl caproate but inhibited by caproate. The production of esterases of koji were not influenced by the substrates for ethyl caproate production but influenced by the growth of koji. The maximum concentration of ethyl caproate produced by rice wine yeast was 0.4 ppm in this research but the production of ethyl caproate by koji was not detected under our experimental conditions. Considering the results of this research, ethyl caproate is not produced by the esterases of koji during brewing but produced by the esterases of rice wine yeast. The growth of rice wine yeast represses that of koji because of the high concentration of ethanol produced by rice wine yeast. The esterases of rice wine yeast may decide the production of ethyl caproate during brewing.
Partitioning of Lactobacillus helveticus Cells and Lactic Acid in Aqueous PEI/HEC Two-Phase Systems.
Microbiology and Biotechnology Letters, volume 26, issue 1, 1998, Pages 55~60
For an ideal extractive bioconversion in aqueous two-phase systems, the product has to be preferentially partitioned into the phase opposite to the one in which the biocatalyst is located. Partitioning behaviors of Lactobacillus helveticus IAM 11090 and lactic acid in aqueous two-phase systems composed a polycation, poly(ethylenimine) (PEI), and an uncharged polymer (hydroxyethyl)cellulose (HEC) were investigated. L. helveticus cells were preferentially partitioned to the HEC-rich top phase while about 85% of lactic acid was partitioned to the PEI-rich bottom phase. These results indicate that extraction of charged, low molecular weight products in an aqueous two-phase systems can be promoted by using an oppositely charged polymer as one of the phase-forming polymer. By the ideal partitioning of the cells and lactic acid, an aqueous PEI/HEC two-phase system can be used as a potential system for the extractive lactic acid fermentation of cheese whey.
Efficient Use of Lactose for Production of the Soluble Recombinant Human Epidermal Growth Factor in Escherichia coli.
Microbiology and Biotechnology Letters, volume 26, issue 1, 1998, Pages 61~67
Recombinant human epidermal growth factor (rhEGF) was produced by E. coli BL2l (DE3) harboring a plasmid pYHB101. The production of rhEGF was 44.5 mg/L when the E. coli BL2l (pYHB101) was cultured at 27
for 48 hr in the modified MBL medium containing 10
/L glucose with 10
IPTG/lactose induction at 2 hr after inoculation. It was shown that lactose is able to induce the rhEGF expression of E. coli BL2l (pYHB101) with the same efficiency as IPTG. In the batch culture system, when induced with 10
lactose, E. coli BL2l (pYHB101) produced maximum 45 mg/L of the rhEGF at 28 hr culture in the modified MBL medium containing 10 g/L glucose. In the semi-fed batch culture system, the volumetric yield was 160 mg/L when the culture was added with 0.5% (w/v) lactose and 0.25% (w/v) yeast extract in the late logarithmic phase and 94.3% of rhEGF was secreted as soluble form. However, when the culture was added with them in the early logarithmic phase, the volumetric yield was 120 mg/L and 20.9% of rhEGF was found in cytoplasmic insoluble aggregates. It was found that the addition time of lactose was important for production of soluble rhEGF from E. coli BL21 (pYHB101).
Overproduction and High Level Secretion of Glucose Oxidase in Saccharomyces cerevisiae
Microbiology and Biotechnology Letters, volume 26, issue 1, 1998, Pages 68~75
The overproduction and high level secretion of Glucose Oxidase (GOD) from A. niger in S. cerevisiae was carried out by cloning GOD gene. For this purpose, using two different strong promoters (ADH1 promoter, GAL10 promoter) and signal sequences (
-MF signal sequence of S. cerevisiae and
-amylase signal sequence of A. oryzae) and GAL7- and GOD terminator, four expression vectors were constructed. All the expression vectors were transformed in S. cerevisiae 2805 using auxotroph method. By the flask culture, transformants of pGAL expression vector series containing GAL 10 promotor showed much higher GOD productivity than transformants of pADH expression vector series containing ADH1 promoter Transformants of pGALGO2 containing GAL10 promotor and
-amylase signal sequence has shown the best productivity of GOD (
: 10.3 unit/mL,
: 8.7 unit/mL) at 115 hr. This value was three fold higher than that of pGALGO1 containing GAL 10 promotor and
-MF signal sequence, even if the same promotor was involved. Through the
-amylase signal sequence of A. oryzae, GOD was secreted much more than the case of
-MF signal sequence from S. cerevisiae. These results suggest that signal sequence may play a important roles in not only the secretion but also the overproduction of foreign protein. Secretion rate of GOD in pGALGO1 and pGALGO2 was 89% and 84%, respectively, Because of the overglycosylation in S. cerevisiae the molecular weight of recombinant GOD in S. cerevisiae was much larger (250 kDa) than that of nature GOD in A. niger (170 kDa).
Selection of Microalgae for Advanced Treatment of Swine Wastewater and Optimization of Treatment Condition.
Microbiology and Biotechnology Letters, volume 26, issue 1, 1998, Pages 76~82
The feasibility of algae as means of removing nitrogen and phosphorus from secondary treated swine wastewater was studied. Among the tested 7 species of Chlorella vulgaris (UTEX 265), Chlorella sp. GE 21, Botryococcus braunii (UTEX 572), Botryococcus sp. GE 24, Scenedesmus quadricauda, Phormidium sp. GE 2, and Spirulina maxima (UTEX 2342), C. vulgaris was selected for its fast growth and abilities to remove nitrogen and phosphorus and to produce algal biomass from swine wastewater. C. vulgaris grew well at 35
, and the optimum initial pH for growth was 8.0. In the effect of light intensity, the growth of C. vulgaris was limited under a light intensity of less than 40
/s. The secondary treated swine wastewater contained 58.7 mg/l of total nitrogen and 14.7 mg/l of total phosphorus, and was diluted to 75, 50, and 25% with groundwater to be treated. Nitrogen and phosphorus were removed by C. vulgaris in all diluted swine wastewaters among which the most effective removal was in 75% swine wastewater (swine wastewater:groundwater=3:1). There was a tendency of linear increase in nitrogen and phosphorus removal time with increasing concentration of swine wastewater. Under the optimized culture condition, total nitrogen and total phosphorus were effectively removed to 95.3% and 96.0%, respectively, in 25% swine wastewater after 4-day incubation.
Heavy Metal Adsorption Capacity of Zoogloea ramigera 115 and Zoogloea ramigera l15SLR.
Microbiology and Biotechnology Letters, volume 26, issue 1, 1998, Pages 83~88
Heavy metal removal by Z. ramigera 115 and soluble slime polymer producing mutant Z. ramigera 115SLR was investigated. Both strains showed similar tolerance against
. When cells were cultivated in the presence of 500 ppm
, the mutant strain removed 1.5 fold more metal than the wild type did at same biomass. Metal adsorption capacities were in the order of Z. ramigera l15SLR polymer > Z. ramigera 115 polymer > Z. ramigera 115 cell >Z. ramigera l15SLR cell. The optimum pH for metal adsorption was 7.5. Langmuir and Freundlich isotherms indicated that Qmax and 1/n of Z. ramigera l15SLR polymer were 164.2 mg
/g dw and 0.496, respectively. These results showed that the polymer of Z. ramigera l15SLR could be used as an effective metal adsorbate.