GOS가 장내 Bifidobacteria의 생육촉진에 미치는 영향에 관한 연구

강국희,문지웅,강대중,이재영 成均館大學校 科學技術硏究所 1993 論文集 Vol.44 No.2

We investigated the growth effect of various sugars on the principal intestinal microorganisms which were Bifidobacteria, Lactobacilli, Streptococci, Clostridia, Escherichia, Eubacteria, and Staphylococci. Those microorganisms were cultivated on media containing various sugars. The sugars were grouped into A, B, and C. Group A consisted of sugars extracted by water, 5%, 15%, 30%, and 40%, EtOH, respectively. Group B were galactooligosaccharide(GOS), fructooligosaccharide(FOS), isomaltooligosaccharide(IMO), and xylooligosaccharide( XOS). Group C were LOS, SOS, and LSOS. Bif. adolescentis, Bif. bifidum, Bif. infantis, Bif. longum, and Str. faecalis grew well on the media containing sugars of each A, B, and C group, while C. butyricurm, S. aureus, Eu. limosum, and E. coli did not. The results indicated that oligosaccharides of A, B, and C group were consumed effectively by Bifidobacterium spp. but not utilized by other intestinal microorganisms. Oligosaccharides of each A, B, and C group promoted selectively the growth of Bif. infantis and Bif. longum in the human intestinal microflora.

Lactobacillus Casei Bacteriophage의 pH에 대한 안정성

姜國熙,朴基文,尹快炳 成均館大學校 1982 論文集 Vol.31 No.-

Survivability of the phages active on the Lactobacillus casei YIT 9018 was studied in skimmiik at various pH. The phages of J1, φ1, TK93, PD2, and PD5 was used for this experiment. Decreases in phage titer in skimmilk at pH 4.0 were observed for 48 hrs. Viability of the phages was not changed for 7 days through the pH range of 8.0 to 5.0. At pH9.0, the titer reduction of phage TK93 was remarkably.

Str.thermophilus 510의 β-Galactosidase 유전자의 Cloning 및 대장균에의 발현

강국희,민해기,이호근,성문희 成均館大學校 科學技術硏究所 1992 論文集 Vol.42 No.2

Chromosomal DNA from Str. thermophilus 510 was purified and cleaved with the restriction enzyme PstI. Chromosomal DNA was ligated to pBR322 for transformation into E. coli JM109. A β-galactosidase positive clone was detected by its blue color on a medium supplemented with 5-bromo-4-chloro-3-indolyl-β-D-galactoside. This transformat possessed a single plasmid, designated pSK 001, which contained, in addition of the vector DNA, A 7.0Kb Pst I insertion fragment coding for β-gal activity. A restriction enzyme map of pSK 001 was consist of Hind Ⅲ, EcoR I, Bgl Ⅱ, Sal I, Pvu Ⅱ, etc. An extract from E. coli JM109 (pSK001) contained a β-gal protein with the same electrophoretic mobility as the β-gal from Str. thermophilus 510.

乳固形分의 농도에 다른 乳酸菌의 生育

姜國熙,李春花 成均館大學校 科學技術硏究所 1992 論文集 Vol.42 No.2

Influence of Solid-Not-Fat concentration on the growth of lactic acid bacteria was investigated in skim milk medium. The cultivation at optimum temperature of each strains was not significant with the various concentration of SNF 10%, 13%, 16%. The viable cell counts of Lac. bulgaricus and Lac. helveticus reached to maximum level of 10^9/ml in 24 hrs incubation and did not counted in 5 days incubation at 40℃. When the cultures (10^9/ml) stored at 30℃, viable cells remained 10^7-8/ml in 7 days. Survival of Lac. acidophilus culture was sustained high level at its optimum temperature for 7 days.

Limulus Amoebocyte Lysate법에 의한 원유와 살균유의 세균수 측정

姜國熙,王智怨,朴興洙,李圭鍾,金敬民 成均館大學校 科學技術硏究所 1993 論文集 Vol.44 No.2

LAL method for the determination of Gram-negative bacterial Lipopolysaccharides(LPS) in milk is proposed and its value for bacteriological quality control is investigated. The relationship between the LPS contents and total colony count(cfu/ml), which covers the Gram-negative bacteria, was determined in raw milk samples. The coefficient of correlation between Gram-negative bacterial counts(cfu/ml) and LPS contents was r^2 =0.969. And, the correlation coefficient between total bacterial counts(cfu/ml) and LPS contents was r^2 =0. 914. It was also investigated how much the LPS contents were in UHT milks from l0 different dairy industrial companies in Korea. It varied from 92 ng LPS/ml to 938 ng LPS /ml.

Bifidobacterium angulatum으로부터 α-galactosidase의 정제 및 특성

강대중,민해기,강국희 成均館大學校 科學技術硏究所 1993 論文集 Vol.44 No.1

α-galactosidase는 (α-D-galactoside galactohydrolase: EC 3.2.1.22)는 다당류나 올리고당인 melibiose, raffinose, stachyose와 guar gum 등의 α-galactosidic 결합을 하고 있는 당을 분해하는 효소이다. 장내세균중 우익균이며 우세균주인 Bifidobacteria로부터 α-galactosidase의 효소학적 특성을 알아보기 위하여 배양여액으로부터 ammonium sulfate분획, 핵산의 제거, Sephadex G-200 gel filtration 및 DEAE-Sephadex A-50 ion exchange chromatography 등의 4단계 정제과정을 거쳐 정제한 결과 약 8배로 정제되어 단일 단백질로 분리하였다. 또한, 효소분해산물을 알아보기 위하여 TLC에 의하여 당분해 및 올리고당의 생성을 알아보았다. 정제효소의 활성 최적온도는 37℃, 최적 pH는 7.0이었다. 효소활성이 K^+, Zn^2+과 같은 금속이온과 8-Hydroxyquinoline, Sodium Bisulfite 등에 의해선 그다지 저해되지 않았으나, Hg^+, Cu^2+과 p-Chloromercuribenzoic acid에 의해선 저해되었다. 효소의 분자량이 301, 995, 합성기질인 PNPG에 대한 K_m은 0.069mM, V_max는 347.22μmol/min.mg protein이었다. To elucidate enzymatic properties of α-galactosidase (EC 3.2.1.22) from Bif.angulatum. α-galactosidase was purified to homogeneity by ammonium sulfate fractionation, protamine sulfate precipitation, sephadex G-200 gel filtration, and DEAE-sephadex A-50 ion exchange chromatography. The purified α-galactosidase was found tobbe homogeneous by SDSpolyacrylamide gel electrophoresis. The molecular weight of this enzyme, estimated by sepadex G-200 gel filtration, was about 301,995. The optimum conditions for the enzyme reaction was pH 6.5 to 7.0 at 37℃. The purified enzyme was stable at 45℃ or below and in buffer at pH 6 to 7.0. The activity was inhibited by mercury, copper ion, and p-chloromercuribenzoic acid. The kinetics of this enzyme, with p-nitrophenyl-α-D-galactoside as substrate, was determined : K_m was about 0.069mM and V_mas was 347.22 μmoles/min mg protein.

김치로부터 분리한 Pediococcus halophilus에 의한 α-Glucosidase의 생산

강국희,민해기,홍승표 成均館大學校 科學技術硏究所 1992 論文集 Vol.42 No.2

Six strains able to efficiently produce α-glucosidase were isolated from kimchi by enrichment culture in APT medium. Among them, Strain No.2 was found to have levels of α-glucosidase activity. The morphological, physiological and biochemical characteristics of the strain No.2 were studied according to the methods of Bergey's manual. Based on the results obtained in these experiments, Stain No.2 was identified to be a similar species to Pediococcus halophilus. The optima conditions for α-glucosidase production were cultured 0.5% starch, 0.4% yeast extract, 0.4% trypticase peptone, initial pH 7.5 at 37℃ and 24 hours cultivation.

Phage耐性突然變異菌의 生育에 관한 연구

姜國熙 成均館大學校 1982 論文集 Vol.32 No.-

A comparative study has been made of growth of L. casei YIT 9018 being used as the starter of fermented milk and the phage insensitive strains obtained by treating L. casei YIT 9018 with Nitrosoguanidine. The results of cultivation parent strain YIT 9018 and 8 strains of phage insensitive stain in skimmilk at 37 C for 30 days has shown that the variables of their viable cells are nearly identical. In order to determine whether these strains are safe against frozen storage their viable cells were counted during 60 day storage at 150C. The result of the study has shown that viable cells remained nearly identical with the level of their unfrozen state. The results of examining the mean generation time of YIT 9018 and pr 38 strain is as follows: the mean generation time of YIT 9018 was 67 minutes in MRT broth and that of YIT 9018 was 86 minutes in skimmilk, while that of PR 38 recorded 63 minutes and 77 minutes in MRT broth and skimmilk respectively.

당귀(Angelica acutiloba)와 감초(Glycyrrhizauralensis)의 열 추출액이 장내 세균의 성장에 미치는 효과

강국희,김경민,정재록 성균관대학교 생명과학자원연구소 1997 生命資源科學硏究 Vol.4 No.2

Bifidobacteriurn longum, Bifidobacterium adolescentis, Clostridium butyricum, Escherichia coli and Eubacterium limosum were cultured on the modified PYF medium containing 0.5% of glucose, heating extract(w/w) of Angelica acutiloba or Glycyrrhiza uralensis, and anaerobically incubated for 48hrs at 37℃. As a control, the same intestinal microorganisms cultured on the PYF medium with no additives and they were compared with other treatments. The addition of the heating extract of Angelica acutiloba increase the growth but optical density was lower than addition of glucose for the growth of intestinal microorgamisms which were investigated in this study. However, the heating extract of Glycyrrhiza uralensis slightly inhibited the growth for most intestinal microorganisms(Bif. longum, Bif. adolescentis, Cl. butyricum, and Eu. limosum) and it had a significant inhibition effect on the growth of Eu limosum when they were compared with control.

보리를 원료로 한 유산균음료의 제조

姜國熙,沈翰燮 成均館大學校 科學技術硏究所 1985 論文集 Vol.36 No.2

An experiment on barley yoghurt, that is cultured lactic acid bacieria in malt sugar syrup, was carried out to find out its suitability to our taste and possibly to promote domestic barley consumption. The results obtained in this experiment were as follows; 1. When we compared the sugar fermentation of three kinds of lactic acid bacteria (Lactobacillus bulg aricus, Streptococcus thermophilus, Streptococcus lactis), Str. lactis was the most suitable one. 2. The growth of lactic acid bacteria was inhibited by the low pH of malt syrup. 3. In the sensory test of samples, no significant differences were noted between market yoghurt and barley yoghurt. 4. In the sensory test, barley yoghurt made of malt sugar syrup showed the best among others.