• Title/Summary/Keyword: Lactose hydrolysis

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Dasania marina gen. nov., sp. nov., of the Order Pseudomonadales, Isolated from Arctic Marine Sediment

  • Lee, Yoo-Kyung;Hong, Soon-Gyu;Cho, Hyun-Hee;Cho, Kyeung-Hee;Lee, Hong-Kum
    • Journal of Microbiology
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    • v.45 no.6
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    • pp.505-509
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    • 2007
  • An obligately aerobic bacterium, strain KOPRI $20902^T$, was isolated from a marine sediment in Ny-${\AA}$lesund, Spitsbergen Islands, Norway. Cells were irregular rods and motile with polar monotrichous flagellum. The optimum growth temperature was $17-22^{\circ}C$. Cells grew best in pH 7.0-10.0 and 3-4% sea salts (corresponding to 2.3-3.1% NaCl). The novel strain required $Ca^{2+}$ or $Mg^{2+}$ in addition to NaCl for growth. Sequence analysis of 16S rRNA gene revealed that the Arctic isolate is distantly related with established species (<92.4% sequence similarity) and formed a monophyletic group with Cellvibrio, which formed a distinct phylogenetic lineage in the order Pseudomonadales. Predominant cellular fatty acids [$C_{16:1}\;{\omega}7c/15:0$ iso 2OH (45.3%), $C_{16:0}$ (18.4%), ECL 11.799 (11.2%), $C_{10:0}$ 3OH (10.4%)]; DNA G+C content (37.0 mol%); nitrate reduction to nitrogen; absence of aesculin hydrolysis, N-acetyl-${\beta}$-glucosaminidase and esterase; no assimilation of arabinose, galactose, glucose, lactose, maltose, and trehalose differentiated the strain from the genus Cellvibrio. Based on the phylogenetic and phenotypic characteristics, Dasania marina gen. nov., sp. nov. is proposed in the order Pseudomonadales. Strain KOPRI $20902^T$ (=KCTC $12566^T$=JCM $13441^T$) is the type strain of Dasania marina.

Microbial β-Galactosidase of Pediococcus pentosaceus ID-7: Isolation, Cloning, and Molecular Characterization

  • Lee, Ji-Yeong;Kwak, Mi-Sun;Roh, Jong-Bok;Kim, Kwang;Sung, Moon-Hee
    • Journal of Microbiology and Biotechnology
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    • v.27 no.3
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    • pp.598-609
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    • 2017
  • Pediococcus pentosaceus ID-7 was isolated from kimchi, a Korean fermented food, and it showed high activity for lactose hydrolysis. The ${\beta}$-galactosidase of P. pentosaceus ID-7 belongs to the GH2 group, which is composed of two distinct proteins. The heterodimeric LacLM type of ${\beta}$-galactosidase found in P. pentosaceus ID-7 consists of two genes partially overlapped, lacL and lacM encoding LacL (72.2 kDa) and LacM (35.4 kDa). In this study, Escherichia coli MM294 was used for the production of LacL, LacM, and LacLM. These three types of recombinant proteins were expressed, purified, and characterized. The specific activities of LacLM and LacL were 339 and 31 U/mg, respectively. However, activity was not detected with LacM alone. The optimal pH of LacLM and LacL was pH 7.5 and pH 7.0, and the optimal temperature of LacLM and LacL was $40^{\circ}C$ and $50^{\circ}C$, respectively. The optimal temperature changes indicate that LacLM is able to achieve higher activity at a relatively lower temperature. LacLM was strongly activated by $Mg^{2+}$, $Mn^{2+}$, and $Zn^{2+}$, which was not true for LacL. Consistent with this, EDTA strongly inactivated LacLM and LacL, but the presence of reducing agents did not dramatically alter the activity. Taken together, multiple alignment of amino acid sequences and phylogenetic analysis results of LacL and LacM of P. pentosaceus ID-7 suggest the evolution of LacL into LacLM and that the use of divalent metal ions results in higher activity.

Studies on the Exo-maltotetraohydrolase of Pseudomonas stutzeri IAM 12097 -Part III. Reaction products and hydrolysis rate on various carbohydrates of Exo-maltotetraohydrolase- (Pseudomonas stutzeri IAM 12097 의 Exo-maltotetraohydrolase에 관한 연구(硏究) -제3보(第三報). 각종기질(各種基質)에 대(對)한 Exo-maltotetraohydrolase의 분해산물(分解産物) 및 분해율(分解率)-)

  • Lee, Mi-Ja;Chung, Man-Jae
    • Applied Biological Chemistry
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    • v.28 no.1
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    • pp.1-7
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    • 1985
  • Exo-maltotetraohydrolase produced by Pseudomonas stutzeri IAM 12097 was characterized with respect to substrate specificity, the reaction products and hydolysis rate on various carbohydrates. Maltopentaose, maltoheptaose, soluble starch, amylose, amylopectin, oyster glycogen and gelatinized starch of corn, potato, glutinous rice, green banana and arrow root were hydolyzed by this enzyme, but ${\alpha},{\beta},{\gamma}-cyclodextin$, sucrose, raffinose, lactose, pullulan, maltose, maltotriose and maltotetraose were not hydrolyzed. Among oligosaccharides, maltohexaose was favorably hydrolyzed by this enzyme and the main reaction product of oligosaccharides and polysaccharides was maltotetraose. Addition of pullulanase to this enzyme increased the hydolysis rate on gelatinized starches. tut it did not on raw starches. Among various starches, corn starch was favorably hydrolyzed by this enzyme, whereas it acted on potato starch, arrow root starch and high amylose corn starch weakly.

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A Numerical Coding System (MCRCODE-N) for Identification of Glucose Nonfermenting Gram-Negative Bacilli (숫자표기에 의한 포도당 비발효균의 동정시안(MCRCODE-N))

  • Hong, Seok-Il;Kim, Chung-Suk
    • Journal of Yeungnam Medical Science
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    • v.2 no.1
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    • pp.183-190
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    • 1985
  • The glucose nonfermenting gram-negative bacilli encountered about 10% of all gram-negative bacilli isolated from clinical material. Therefore, a rapid and correct identification of glucose nonfermenting gram-negative bacilli is impostent for a better management of infectious disease. There are many conventional systems for the Identification of glucose nonfermenting gram-negative bacilli but most of them have problems and difficulties. Commercial Kit Systems exist and they are too expensive for dally use 10 Korea because of high cost. Based on 12 selected tests we propose a new code system, MCRCODE-N for rapid and 10-expensive identification of glucose nonfermenting gram-negative bacilli. The selective 12 tests are oxidase, glucose oxidation motility, urease, DNase arginine dehydrolase, nitrate reduction, gelatin Liquefaction, esculin hydrolysis, mannitol oxidation, maltose oxidation, Lactose oxidation. The 12 tests are divided 4 group and then each group has 3 tests. The result of each group is expressed by the number as below. The positive test is given by specific number (1st test = 1, 2nd test = 2, 3rd test = 4), while any negative result is 0. Each 3 numbers of one group are added and make number of 1 digit. Four digit number is refered to the code book of MCRCODE-N system or MCRCODE system using computer (Apple-II model) created by authors. This MCRCODE-N system is suitable ones for our use 10 Korea. We propose the MCRCODEN-N system for clinical use.

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Hydrolysis of Cellulose by Immobilized Cellulase in a Packed Bed Reactor (충진층 반응기에서 고정화 cellulase에 의한 셀룰로스 가수 분해)

  • Kang, Byung Chul;Lee, Jong Baek
    • Journal of Life Science
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    • v.23 no.11
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    • pp.1365-1370
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    • 2013
  • Immobilized cellulase on weak ion exchange resin showed a typical Langmuir adsorption isotherm. Immobilized cellulase had better stability with respect to pH and temperature than free cellulase. Kinetics of thermal inactivation on free and immobilized cellulase followed first order rate, and immobilized cellulase had a longer half-life than free cellulase. The initial rate method was used to characterize the kinetic parameters of free and immobilized enzyme. The Michaelis-Menten constant $K_m$ was higher for the immobilized enzyme than it was for the free enzyme. The effect of the recirculation rate on cellulose degradation was studied in a recycling packed-bed reactor. In a continuous packed-bed reactor, the increasing flow rate of cellulose decreased the conversion efficiency of cellulose at different input lactose concentrations. Continuous operation for five days was conducted to investigate the stability of long term operation. The retained activity of the immobilized enzymes was 48% after seven days of operation.

Fermentation Properties of Yogurt Added by Lycii fructus, Lycii folium and Lycii cortex (구기자, 구기엽 및 지골피를 첨가한 요구르트의 발효 특성)

  • 조임식;배형철;남명수
    • Food Science of Animal Resources
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    • v.23 no.3
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    • pp.250-261
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    • 2003
  • This experiment was carried out to examine the fermentation properties of yogurt with Lycii fructus, Lycii folium and Lycii cortex powder, and extract additives at concentrations of 0.5, 1.0, 2.0, 4.0, and 6.0%. Lactic acid bacteria was used in a mixed starter culture of Streptococcus salivarius ssp. thermophilus(ST36) and Lactobacillus delbrueckii ssp. bulgaricus(LB12). When the boxthorn was added with extract types, the changes of pH, acidity and lactic acid bacteria counts of yogurt during the fermenation of 3 hours were pH 5.64, titratable acidity 0.85%, 5.80xl0$\^$6/cfu/ml of viable cell counts for control yogurt, whereas those were pH 4.10∼5.06, titratable acidity 0.98∼1.27%, 1.80∼9.60x10$\^$7/ cfu/ml of viable cell counts for Lycii fructus extract yogurt. The lactose hydrolysis ratio was better for 1.0% Lycii fructus extract yogurt(42.00%) and 1.0% Lycii folium extract yogurt(41.46%) than for control yogurt(28.40%). Also, content of lactic acid of 1.0% Lycii fructus(11.9 times) and 1.0% Lycii folium extract yogurt(10.6 times) produced more than control yogurt(7.3 times). The viscosity of yogurt was better for boxthorn extract yogurt(1,027∼1,382 cps) than for control yogurt(975cps). The sensory scores of color, taste and overall acceptability of yogurt with 0.5, and 1.0% Lycii fructus extract additive were better than other groups. The yogurts made with increased Lycii fructus extract concentration(0.5∼6.0%), showed the increase of lactic acid, titratable acidity, number of lactic acid bacteria, viscosity and lactose hydrolysis rate compared to the treatments of 0.5, 1.0, 2.0, and 4.0% Lycii folium and Lycii cortex extract and powder yogurt. We gained excellent results from the yogurt to which Lycii fructus extract was added with 0.51.0% concentration.

Distribution and Bacteriological Characteristics of Vibrio vulnificus (Vibrio vulnificus 균의 분포 및 세균학적 특성)

  • CHANG Dong-Suck;SHIN Il-Shik;CHOI Seung-Tae;KIM Young-Man
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.19 no.2
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    • pp.118-126
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    • 1986
  • Vibrio vulnificus is a recently recognized halophilic organism that nay cause serious human infections. Patients infected with V. vulnificus often have a history of exposure to the sea, suggesting that the organism may be common inhabitant of marine environment. The purpose of this experiment is to investigate the distribution and bacteriological characteristics of V. vulnificus. The strain used in this experiment was isolated from sea water and sea products such as common octopus (Octopus variabilis), ark shell (Anadara broughtonii), blue crab (Ericheir japonica), and sea squirt (Synthia roretzi) collected in Pusan area from July to October in 1985. V. vulnificus was frequently isolated in August when temperature of sea water was around $26^{\circ}C$ and rarely isolated in October when temperature of sea water was around $18.5^{\circ}C$. The distinctive biochemical characteristics of V. vulnificus were ONPG hydrolysis positive and fermented lactose and not grown in peptone water contained $8\%$ NaCl. The optical density at 660 nm of the growth of V. vulnificus was reached maximum level after 8 hours of culture at $35^{\circ}C$ in brain heart infusion broth but that of V. vulnificus was little increased at $15^{\circ}C$ for 14 hours. Optimum temperature and pH for the growth of V. vulnificus were around $35^{\circ}C$ and 8.0. The specific growth rate and the generation time of V. vulnificus isolated from the samples were $1.21\;hr^{-1}$, 34 min at $35^{\circ}C$ and $0.61\;hr^{-1}$, 69 min at $25^{\circ}C$, respectively. V. vulnificus did not grow on eosin-methylene-blue agar, salmonella-shigella agar, deoxycholate agar but grew well on Endo agar, xylose-lysine-deoxycholate agar and hektoen enteric agar. On Endo agar, the colonies of V. vulnificus were red and achieved a diameter of 2 to 4 mm as a feature enabling differentiation of V. vulnificus from other Vibrio spp. V. vulnificus grow well on TCBS agar forming green colonies. V. vulnificus refrigerated at $4^{\circ}C$ exhibited a linear decline of its viablity as 1 log cycle in every 16 hours storage, while V. vulnificus freezed at $-18^{\circ}C$ almost became extinct.

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Studies on immobilization and application of beta-galactosidase II. Preparation and properties of the immobilized enzyme from Aspergillus niger CAD 1 (beta-Galaetosidase의 고정화 및 응용에 관한 연구 제2보: Aspergillus niger CAD 1의 효소 교정화 조건 및 고정화 효소의 성질)

  • Lee, Yong-Kyu;Cuun, Soon-Bae;Choi, Won-Ki;Chung, Ki-Chul;Bae, Suk;Kim, Kwan-Chun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.15 no.4
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    • pp.40-46
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    • 1986
  • The beta-galactosidase of Aspergillus niger CAD 1 described in previous report was immobilized to cellulose triacetate. The optimal conditions for immobilization of the enzyme were obtained when 13%(v/v) of the soluble enzyme (349 unit/ml) was entrapped in fiber prepared from 10%(w/v) cellulose triacetate in methylene chloride. The optimal temperature and pH for the activity of the immobilized enzyme were $45^{\circ}C$ and 4.5, respectively, which stowed the same values as those of the soluble enzyme. It was found that Km of the immobilized enzyme for lacotse exhibited high value compared with that of the soluble enzyme. The immobilized enzyme showed good storage stability, reusability, and also hydrolysis of lactose when introduced into skim milk and acidic whey.

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Properties of the Mixed Fermentation Milk Added with Red Ginseng Extract (홍삼 추출물 첨가 혼합 발효유의 특성)

  • Bae Hyoung-Churl;Nam Myoung-Soo
    • Food Science of Animal Resources
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    • v.26 no.1
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    • pp.127-135
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    • 2006
  • This experiment was carried out to examine the fermentation properties of yogurt with bovine milk and soybean milk at the mixed ratio of 2:1 and added 0.1, 0.2, 0.4 and 1.0% red ginseng extract. The effect on promoting the fermentation by additives 0.1, 0.2, 0.4 and 1.0% red ginseng extracts were higher and pH was $3.90{\sim}3.94$ when Lactobacillus acidophilus KCTC3150 and Lactobacillus salivarius ssp. salivarius CNU27 were used. Titratable acidity showed a little inhibiting due to increasing red ginseng extract content. The average viable counts of lactic acid bacteria after 15 hour culture was the highest level of $6.26{\times}10^8cfu/mL$ when Lactobacillus acidophilus KCTC3150 was used, and the additives content of red ginseng extract was 1.0% The production of lactic acid was the highest and the concentration was 332.22 mM when Lactobacillus acidophilus KCTC3150 was used, and the additives content of red ginseng extracts was 1.0% Lactose hydrolysis was completely hydrolyzed when Lactobacillus acidophilus KCTC3150 and Lactobacillus salivarius ssp. salivarius CNU27 were used. The highest viscosity of yogurt was 780 cP when Lactobacillus acidophilus KCTC3150 and Lactobacillus salivarius subsp. salivarius CNU27 were used and red ginseng extract was added 1.0% The overall acceptability, $4.17{\pm}0.64$, was the highest when Lactobacillus salivarius subsp. salivarius CNU27 was used and the additives content of red ginseng extract was 0.2%.

Fermentation Properties and Functionality of Yogurt added with Lycium chinence Miller (구기자(Lycium chinence Miller) 첨가에 따른 요구르트의 발효 특성과 기능성)

  • Bae, H,C.;Cho, I.S.;Nam, M.S.
    • Journal of Animal Science and Technology
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    • v.46 no.4
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    • pp.687-700
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    • 2004
  • This experiment was carried out to examine the fennentation properties of yogurts with or without Lyeii fructus, Lyeii folium and Lyeii cortex extract as additives at concentrations of 1.0%. The effects on promoting the fermentation by Lycii fructus, Lycii folium and Lycii cortex additives were higher and pH was below 4.06 when Streptococcus salivarius ssp. thermophilus and Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus cosei, and Lactobacillus acidophilus, Bifidobacterium longum and Streptococcus salivarius ssp. thermophilus were used. The acid production was higher when S. salivarius ssp. thermophilus and L. delbrueckii ssp. bulgaricw were used. The average lactic acid bacteria counts was 2.62 ${\times}$ $10^9$ cfu/ml in the yogurt added with Lycii fructus extract and fermentation with S. salivarius ssp. thermophilus and L. delbrueckii ssp. bulgaricw. The lactose hydrolysis ratio was higher in the milk added with Lycii fructus extract(36.11%), Lycii folium extract(37.76%) and Lycii cortex extract(32.70%) when S. salivarius ssp. thermophilus and L. delbrueckii ssp. bulgaricus were used. The isobutylic acid concentration was(34.39 to 37.72 mM) with S. salivarius ssp. thermophilus and L. delbrueckii ssp. bulgaricus. The viscosity of yogurt was 1,615 to 2,030 cP in yogurts added with skim milk and L. acidophilus; B. longum and S. salivarius ssp. thermophilus were used. The sensory scores of colors, tastes and overall acceptability of yogurt with Lycii cortex extract were shown 3.34 to 3.77 when fermented by L. cosei, L. acidophilus, B. longum and S. salivarius ssp. thermophilus. The cholesterol reducing effects were 17.38${\sim}$32.08% in all the yogurts and especially, greater effect(25.75 to 32.08%) for yogurts fermented with L. acidophilus KCTC3150 and L. salivarius subsp. salivarius CNU27. The inhibitory effects on the pathogenic bacteria by lactic acid bacteria added with Lycii fructus, Lycii folium and Lyeii cortex lower on S. typhimurium M-15, but higher on E. coli KCTC1021 and L. monocytogenes.