• Biotechnology and Bioprocess Engineering:BBE
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• 제7권4호
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• pp.234-236
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• 2002

A process for the production of mannitol from fructose (5% to 25%) using Leuconostoc mesenteroides NRRL B-1149 was investigated. Fermentations were carried out In batch or fed-batch fermentations without aeration at 28$\^{C}$, pH 5.0. When 5% fructose was used In batch culture fermentation, the yield of mannitol was 78% of that expected theoretically. When the frurtose concentration was Increased to 10%, the yield dropped to 59.6% of the theoretical value. However, In the fed-batch culture, using 10% fructose, the yield was 81.9% of the theoretical value. In a 15% fruttose fed-batch culture, with 5% fructose being added initially and the other 10% fructose being added as a continuous supply the final yield was 83.7% of the theoretical yield. When 20% fructose was used In the same manner, the yield was 89.5% of theoretical yield.

• Journal of Microbiology and Biotechnology
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• 제21권9호
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• pp.968-971
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• 2011

Leuconostoc genus, which comprise heterofermentative lactic acid bacteria, reduces fructose to mannitol by recycling intracellular NADH. To evaluate the mannitol productivities of different Leuconostoc species, 5 stock cultures and 4 newly isolated strains were cultivated in MRS and simplified media containing glucose and fructose (1:2 ratio). Among them, L. citreum KACC 91348P, which was isolated from kimchi, showed superior result in cell growth rate, mannitol production rate, and yield in both media. The optimal condition for mannitol production of this strain was pH 6.5 and $30^{\circ}C$. When L. citreum KACC was cultured in simplified medium in a 2 l batch fermenter under optimal conditions, the maximum volumetric productivity was 14.83 $g{\cdot}l^{-1}h^{-1}$ and overall yield was 86.6%. This strain is a novel and efficient mannitol producer originated from foods to be used for fermentation of fructose-containing foods.

• Journal of Microbiology and Biotechnology
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• 제28권12호
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• pp.2009-2018
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• 2018

Leuconostoc mesenteroides can be used to produce mannitol by fermentation, but the mannitol productivity is not high. Therefore, in this study we modified the chromosome of Leuconostoc mesenteroides by genetic methods to obtain high-yield strains for mannitol production. In this study, gene knock-out strains and gene knock-in strains were constructed by a two-step homologous recombination method. The mannitol productivity of the pat gene (which encodes phosphate acetyltransferase) deletion strain (${\Delta}pat::amy$), the fk gene (which encodes fructokinase) deletion strain (${\Delta}fk::amy$) and the stpk gene (which encodes serine-threonine protein kinase) deletion strain (${\Delta}stpk::amy$) were all increased compared to the wild type, and the productivity of mannitol for each strain was 84.8%, 83.5% and 84.1%, respectively. The mannitol productivity of the mdh gene (which encodes mannitol dehydrogenase) knock-in strains (${\Delta}pat::mdh$, ${\Delta}fk::mdh$ and ${\Delta}stpk::mdh$) was increased to a higher level than that of the single-gene deletion strains, and the productivity of mannitol for each was 96.5%, 88% and 93.2%, respectively. The multi-mutant strain ${\Delta}dts{\Delta}ldh{\Delta}pat::mdh{\Delta}stpk::mdh{\Delta}fk::mdh$ had mannitol productivity of 97.3%. This work shows that multi-gene knock-out and gene knock-in strains have the greatest impact on mannitol production, with mannitol productivity of 97.3% and an increase of 24.7% over wild type. This study used the methods of gene knock-out and gene knock-in to genetically modify the chromosome of Leuconostoc mesenteroides. It is of great significance that we increased the ability of Leuconostoc mesenteroides to produce mannitol and revealed its broad development prospects.

• 대한미생물학회지
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• 제20권1호
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• pp.13-23
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• 1985

This investigation was performed to isolate and identify Staphylococcus sp. from air at the 25 sites in one hospital in Daegu. Drug sensitivity tests bacteriologically were also studied. The results are summarized as follows: 1. In gram staining of isolated colonies, the number of staphylococci strains was 959(70.2%) among 1367 collected in the morning, and 653(66.2%) among 987 collected in the afternoon. 2. The number of isolates was slightly higher in samples collected from the outpatient treatment rooms and wards in the main building than in samples from the other sites. 3. In biochemical tests of 1612 strains of isolates gram positive cocci, the number of coagulase positive strains was 584(36.2%) and coagulase negative 1028(63.8%). In experiments on growth on mannitol agar containing 7.5% NaCl and mannitol fermentation tests, the number of mannitol fermentation strains was 423(30.8%) and nonfermenter was 951(59.2%). 4. In antibiotic sensitivity tests of 746 identified strains of staphylococci, coagulase positive strains showed resistance in. higher portions to penicillin(89.7%), chloramphenicol(64.6%), gentamycin (52.1%) and tetracycline(45.2%), whereas in lower portions to kanamycin(39.2%) and apmicillin(33.1%). 5. Among coagulase negative and mannitol fermenting strains, higher portions showed resistance to chloramphenicol(76.5%), penicillin(69.8%) and ampicillin(63.6%), whereas lower portions showed resistance to kanamycin(48.8%), tetracycline(39.5%) and gentamycin(34.0%). 6. The number of strains showing multiple resistance to above 6 antibiotics were 15(52(19.8%) among coagulase positive and mannitol non-fermenter and 36(22.2%) among coagulase negative and mannitol fermenter.

• Journal of Microbiology and Biotechnology
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• 제30권7호
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• pp.1060-1066
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• 2020

This study was focused on developing and obtaining a kimchi starter for use in commercial kimchi production. Kimchi varieties made with selected starters are of high quality, have high levels of mannitol, and extended shelf life. The starters were screened for properties such as mannitol production, low gas/acid production, and acid resistance. Finally, kimchi fermentation testing was performed using selected LAB starters. Kimchi samples were prepared with lactic acid bacteria (LAB) starters, including Leuconostoc mesenteroides PBio03 and Leuconostoc mesenteroides PBio104. The LAB starters are isolated from kimchi and can grow under pH 3.0 and low temperature conditions of 5℃. Four kimchi samples were fermented and stored for 28 days at 5℃. The kimchi samples made with starters (PBio03 and PBio104) had better quality (production of mannitol and maintenance of heterofermentative LAB dominance) than the non-starter kimchi samples. In the starter kimchi, Leu. mesenteroides was the dominant LAB, comprising 80% and 70% of total LAB counts at 7 and 21 days, respectively. Mannitol content of the kimchi with Leu. mesenteroides PBio03 was 1,423 ± 19.1 mg/100 g at 28 days, which was higher than that of the non-starter kimchi sample (1,027 ± 12.2 mg/100 g). These results show the possibility of producing kimchi with improved qualities using Leu. mesenteroides PBio03 and PBio104 as starters.

• 생명과학회지
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• 제15권3호
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• pp.374-381
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• 2005

기능성 식품 첨가물 중에서 당 알코올은 최근 그들의 탁월한 기능성이 알려지면서 수요가 증가하고 있다. 당 알코올 중에서, 만니톨$(C_6H_{14}O_6)$은 식품, 화장품, 제약 산업 등에 매우 광범위하게 이용되고 인체에 독성이 없어 미국 FDA에 의하여 GRAS (Generally Recognized As Safe)로 승인이 되어 이에 대한 수요량이 급격히 증가하는 추세이다. 본 연구는 발효 김치에서 분리 된 L. mesenteroides sp. strain JFY 균주를 이용하여 과당으로부터 만니톨 생산을 위한 최적 생물 전환 조건을 확립하기 위한 것이다. 만니톨 생산을 위한 최적 조건들은 pH 6.5, 배양온도 $28^{\circ}C$, 효모 추출물의 농도 $0.5\%$, 과당의 농도는 $10\%$이었고, 이 조건에서 최대 만니톨생산은 31.5g/l이었다.

• Journal of Microbiology and Biotechnology
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• 제16권2호
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• pp.325-329
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• 2006

Leuconostoc mesenteroides B-742 fermentations with maltose as an acceptor were tested for glucooligosaccharides and mannitol co-production. Leuconostoc oligosaccharides were produced that were oligomers with a size range of DP 2 to 7 and were primarily DP 3, 4, 5, and 6, containing mainly ${\alpha}-1,4$ and ${\alpha}-1,6$ linkages. Maltose was linked to the reducing end of the isomaltosyl residues. The $Ca^{2+}$ form of cation-exchange column could separate glucooligosaccharides from byproducts.

• 한국식품영양과학회지
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• 제27권1호
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• pp.16-23
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• 1998

Effect of Fermentation temperature on the changes of chemical components in Kakudgi during fermentation was investigated by measuring free sugar, organic acid and volatile compounds up to 57 days at several temperatures. The mannitol was increased in palatable period in contrast with those of other free sugars. The higher the initial fermentation temperature was and the longer the initial fermentation time at 2$0^{\circ}C$ was, the faster the second increasing period was and the less the initial contents was. Lactic acid was increased 6~31 times from a little amount at the initial period. The higher the initial fermentation temperature was and the more the increasing content was. But malic acid which was abundant(55.1% of total nonvolatile organic acid) in the initial fermentation period was remarkably decreased in the palatable period. The change of the sulfides among the volatile compounds was remarkable. Methyl allyl sulfide which was a little in the initial fermentation period was remarkably increased in the final fermentation period, and the correlation coefficients between the content of methyl allyl sulfide and aroma in sensory evaluation were high. It could be suggested that the fermentation temperature should be set to 4$^{\circ}C$ after fermentating at 2$0^{\circ}C$ for 36 hours in the view point of keeping the Kakdugi taste and quality well because of high content of free sugar and nonvolatile organic acids.

• Journal of Microbiology and Biotechnology
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• 제11권4호
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• pp.700-703
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• 2001

The influence of process conditions on highly branched glucooligosaccharides production by mixed culture of Leuconostoc mesenteroides ATCC 13146 and Lipomyces starkeyi ATCC 74054 was studied. We divided the batch culture fermentations into two groups according to inoculation method. One-point inoculation was performed by coinoculation of L. mesenteroides and L. starkeyi at the ration of 10 to 1, and two-point inoculation by L. mesenteroides inoculation first and L. starkeyi inoculation after L. mesenteroides grew to the end of the log phase of growth. Two-point inoculation improved the yield of oligosaccharide by 1.5 to 20 fold more than one-point inoculation. In this process, the highest yield of oligosaccharides (48% of theoretical yield) and productivity (0.85 g/l/h) were obtained with starch as an initial substrate for L. starkeyi growth. The estimated composition of the end product consisted of 31.5% oligosaccharides, 17.6% dextran, and 46.5% mannitol.

• Restorative Dentistry and Endodontics
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• 제6권1호
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• pp.93-103
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• 1980

Streptococcus mutans were isolated from dental plaques of carious lesions of 4 patients on mitis-salivarius agar medium. Three patients known to harbor S. mutans in their dental plaques. Identification of the isolated S. mutans was established by colonial morphology on mitis-salivarius agar medium, the fermentation of mannitol and sorbitol, and confirmed by agglutinating reaction with home made anti-S. mutans NCTC 10449 (serotype c) antiserum. Of the isolated S. mutans, one strain (P2-1) showed strong agglutinating reaction with antiserum, another strain (P1-2) showed weak agglutinating reaction. P2-1 strongly adhered to the wall of the test tube containing 5% sucrose broth, while p1-2 weakly colonized on the wall of the test tube. Biotyping of the isolated S. mutans based on the fermentation of mannitol, sorbitol, raffinose and melibiose, and the production of ammonia from L-arginine, and the inhibition of acid production by bacitracin. Biochemical characteristics of P2-1 strain correlated with the recognized biotype c, pl-2 strain resembled biotype d of S. mutans.