• Analytical Science and Technology
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• 제5권4호
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• pp.471-475
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• 1992

We have developed the methodology for the quantitative analysis of microencapsulation yield and optimized the conditions for the microencapsulation of ${\beta}$-galactosidase by butter oil. The degree of ${\beta}$-galactosidase deactivation by the microencapsulation process was the value of 5.2% of initial activity. And the yield for the microencapsulation of ${\beta}$-galactosidase by the indirect, heat treatment, and enzymatic methodology were 92.6%, 88.6%, and 94.1%, respectively.

• Microbiology and Biotechnology Letters
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• 제25권2호
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• pp.144-150
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• 1997

After DNA damage, umuDC is the only SOS operon that must be induced to promote SOS mutagenesis in Escherichia coli. The recombinant plasmid pBC401 and pBC402 were constructed to fuse the lac structural genes with promoter region of umuDC operon to induce the expression of lacZ gene by DNA damage. We transformed the plasmid pBC401 and pBC402 into E. coli MC1061, lacZ deleted strain and determined the activity of $\beta$-galactosidase for various mutagen; UV, mitomycin C (MMC), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 4-nitroqunoline-1-oxide (NQO), ethyl methanesulfonate (EMS). The $\beta$-galactosidase activities of PBC401 and pBC402 for UV, MMC, and NQO were increased in proportion to expression time until 3 hours thereafter, the activities were constant or slightly decreased. The activities for MNNG and EMS were not so high as for UV, MMC, and NQO. When MNNG and EMS were treated, $\beta$-galactosidase activity of pBC402 was slightly lower than pBC401 but when UV, MMC, and NQO were treated in pBC402, $\beta$-galactosidase activity was slightly higher than in pBC401. Therefore, the pBC402 was better than the pBC401 in terms of sensitivity for frameshift mutagen. We suggest that the plasmid pBC401 and pBC402 are easy to detect mutagens which cause frameshift mutation rather than point mutation.

• Journal of Food Hygiene and Safety
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• 제2권2호
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• pp.67-73
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• 1987

Kluyveromyces fragilis로부터 $\beta$-galactosidase의 생성조건과 조효소액의 성질 그리고 당 전이 반응에 의한 oligosaccharide 생성을 조사한 결과 다음과 같은 결과를 얻었다. \circled1 Peptone-Yeast extract 배지에 6% lactose를 첨가하였을 때 최대 효소생산을 보였다. \circled2 0.05 M potassium phosphate buffer (pH 7.0)에서 3% toluene를 첨가하여 37$^{\circ}C$ 5시간 배양하였을 때 K. fragilis로부터 효소가 최대로 추출되었다. \circled3 효소의 최적온도는 4$0^{\circ}C$이고 4$0^{\circ}C$ 이상의 열처리에서는 효소가 파괴되었으며, pH6-7에서는 상당히 안정하였다. \circled4 ONPG 기질로 사용하였을 때 Km 값은 2.5mM이었다. \circled5 당 전이 반응의 결과, 7개의 oligosaccharide가 생성되었다. 이상의 실험결과로 볼 때, 본 실험에 사용한 K. fragilis SKD 7001은 Beta-galactosidase의 생산을 위해서 이용 가치가 인정되었으며, 특히, 이 효소의 활성이 중성 pH에서 강하고 안정한 상태를 보이는 것은 시유나 원료우유의 lactose를 중성에서 해야 한다는 점을 고려할 때, 실용적 가치가 있다고 본다. 또, 이 효소의 작용과정에서 생성되는 oligosacchride는 장내 bifidus균의 생육을 촉진시키는 효과가 인정되고 있기 때문에 이용가치를 더욱 높여주는 것으로 생각된다.

• KSBB Journal
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• 제9권4호
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• pp.400-405
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• 1994

The conditions for ${\beta}$-galactosidase production from alkalophilic, thermophilic Bacillus sp. TA-11 were investigated. The maximal enzyme production was obtained when the strain was cultured at $50^{\circ}C$ for 5 days with fed-batch culture in the optimal medium containing 1.5% lactose, 0.6% yeast extract 0.15% $K_2HP0_4$and initial pH 9.5, and then final enzyme activity under the above conditions was 5200 unit/ml of cell free extract.

• Food Science and Preservation
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• 제2권1호
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• pp.173-183
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• 1995

This paper was carried out to investigate changes in chromatograms of polysacctatides and soluble pectins on Sephadex G-50 and non-cellulosic neutral sugars of polysaccharides isolated from cell wall of persimmon fruits treated with polygalacturonase and $\beta$-galactosidase in vitro. The chromatogram pattern of soluble pectins extracted from cell wall treated with $\beta$-galactosidase on Sephacryl S-500 column were similar to those of untreatment, but contents of soluble pectins treated with $\beta$-galactosidase were different from those of untreatment. The patterns of chromatograms In soluble pectins extracted from cell wall treated with polygalacturonase were more complex and lower molecular polymer than those of other cell wall-degrading enzyme treatments. Non-cellulosic neutral sugar of polysaccharides in fraction I of soluble material treated with polygalacturonase was rhamnose, those in fraction II were similar to those in fraction III and contents of arabinose, xylose and glucose were higher than contents of other non-cellulosic neutral sugars. Non-cellulosic neutral sugars of polysaccharides in fraction I in soluble material by $\beta$-galactosidase treatment were rhamnose, arabinose, galactose and mannose. Content of glucose of polysaccharides in fraction II was higher than that in fraction I . Non-cellulosic neutral sugars treated with mixed enzyme were rhamnose, fucose, arabinose, xylose, mannose, galactose and glucose. Compositions of non-cellulosic neutral sugars of polysaccharides in fraction I were similar to those in fraction II and III.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 한국미생물생명공학회 1979년도 춘계학술대회
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• pp.113.2-114
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• 1979

$\beta-Galactosidase$ is an enzyme which catalizes hydrolysis of lactose, a natural substrate, to glucose and galctose and transferring some monosac-charide units to active acceptors as sugar or alcohol. The occurence of $\beta-Galactosidase$ is known in various microorganisms, animals and higher plants and has been studied by many investigatigators. Especially, a great deal of articles for the enzyme of E. coli have been presented in genetic control mechanism and induction-repression effects of proteins, On the other hand, in the dairly products industry, it is important to hydrolyes lactosd which is the principal sugar of milk and milk products. During the last few years, the interest in enzymatic hydrolysis of milk lactose has teen increased, because of the lactose intolerence in large groups of the population. Microbial $\beta-Galactosidases$ are considered potentially most suitable for processing milk to hydrolyse lactose and, in recent years, the immobilized enzyme from yeast has been examined. Howev, most of the microbial $\beta-Gal$ actosidase are intracellular enzymes, except a few fungal $\beta-Gala-$ ctosidases, and extracellular $\beta-Galactosidase$ which may be favorable to industrial applieation is not so well investigated. On this studies, a mold producing a potent extracellular $\beta-Galactosidase$ was isolated from soil and identified as an imperfect fungus, Beauveria bassians. In this strain, both extracellular and intracellular $\beta-Galactosidases$ were produced simultaneously and a great increase of the extracellular production was acheved by improving the cultural conditions. The extracellular enzyme was purified more than 1, 000 times by procedures including Phosphocellulose and Sephadex G-200 chromatographies. Several characteristics of the enzymewas clarified with this preparation. The enzyme has a main subunit of molecular weight of 80, 000 which makes an active aggregate. And at neutral pH range, it has optimum pH for activity and stability. The Km value was determined to be 0.45$\times$10$^{-3}$ M for $o-Nitrophenyl-\beta-Galactoside.$ In any event, it is interesting to sttudy the $\beta-Galactosidase$ of B. bassiana for the mechanism of secretion and conformational structure of enzyme.

• Microbiology and Biotechnology Letters
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• 제9권4호
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• pp.213-218
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• 1981

The molecular weight of the purified $\beta$-galactosidase of Penicillium sp. was estimated to be 130000 by both Sephadex G-200 gel filtration and SDS-polyacrylamide del electrophoresis. The SDS-electrophoresis gave two protein bands corresponding to the two molecular weights of 130000 and 70000. These results indicated that the enzyme consisted of two probably identical subunits which had a molecular weight of 70000. The optimum pH of the enzyme activity was 4.7 and maximum activity appeared at 5$0^{\circ}C$. The stable pH range for the enzyme was from 4.5 to 7.0. The purified $\beta$-galactosidase had no metal ion requirement for its activity or stability. The enzyme activity was inhibited by C $u^{++}$(1mM)and galactose (100mM). The hydrolysis of lactose in 5% lactose solution, pasteurized milk and 10% skim milk solution were 69.5%, 88.7% and 72.6% after 4 hr incubation at 5$0^{\circ}C$, when 10 units of $\beta$-glucosidase were used per $m\ell$ of the substrate solutions.s.

• Journal of Microbiology and Biotechnology
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• 제4권3호
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• pp.200-203
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• 1994

Spodoptera frugiperda IPLB-SF-21-AE cells were cultivated in a spin-filter bioreactor with continuous perfusion for the recombinant $\beta$-galactosidase production. At the perfusion rate of 0.06 $hr^{-1}$, the maximum cell density of insect cells in this bioreactor system reached 3.5$\times$$l0^6$ viable cells/ml using the Grace media containing 5% FBS and 0.3% Pluronic F-68. The recombinant $\beta$-galactosidase production of 8, 100 units per reactor volume was also achieved at this perfusion rate.

• KSBB Journal
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• 제15권1호
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• pp.84-87
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• 2000

We studied the effect of ultrasoft X-ray obtained from the Pohang Light Source (PLS), on the mutation of E. coli and the damage of plasmid. After irradiation, the supercoiled plasmid DNA converted to the relaxed-form, and then to the linear-form. We transformed the irradiated plasmid DNA and isolated $\beta$-galactosidase mutants. We also isolated $\beta$-galactosidase mutants from the directly irradiated cells. There were preferred mutational sites on DNA induced by ultrasoft X-ray.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 한국축산식품학회 2004년도 제34차 추계 국제 학술대회
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• pp.384-387
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• 2004

겨울철 토양에서 ${\beta}-Galactosidase$를 생산하는 균주를 분리하였으며 동정한 결과 그람 음성 간균이고 Pantoea spp. 로 확인되었다. Pantoea spp. 균주의 세포 추출물로부터 DEAE-Sephacel chromatography와 affinity chromatography를 이용하여 ${\beta}-Galactosidase$를 분리하였다. Pantoea spp. 의 ${\beta}-Galactosidase$의 반응 최적 온도는 $45^{\circ}C$이이고 최적 pH는 $5.5{\sim}7.5$이고 열안정성을 조사한 결과 $45^{\circ}C$이상의 온도에서 불활성 되는 것으로 나타났고 E. coli에서 분리된 효소보다 저온에서의 활력이 좋았지만 상업적인 효소인 Kluyveromyces lactis (Validase) 보다는 낮았다.