• KSBB Journal
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• v.11 no.6
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• pp.636-641
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• 1996

The production of extracellular mannitol by a new mannitol-producing bacterium, Leuconostoc sp. KY-002 was studied in shake flask cultures. The new isolate has a capability of utilizing fructose and sucrose for mannitol formation. Maximum mannitol production was obtained with fructose as the sole carbon source. Under the optimal culture conditions, within 70 hours of incubation, a final concentration of 26 g/L of mannitol from 50 g/L fructose was obtained with an indicated yield of 52% based on fructose consumed. However, higher concentrations of fructose ranging from 100 to 250 g/L could not effectively be transformed to mannitol due to a lack of osmotolerance. The strain produced no other polyols such as glycerol and sorbitol as by-products. Yeast extract was the best nitrogen source and high levels of inorganic phosphate up to 10 g/L promoted mannitol formation. Any mineral ions and salts did not play important role in both cell growth and mannitol production. Nicotinic acid enhanced mannitol production by 16%. The optimum culture temperature and initial pH were $35^{\circ}C$ and 6, respectively.

• KSBB Journal
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• v.11 no.3
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• pp.374-379
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• 1996

The production of extracellular mannitot by an efficient mannitol-producing bacterium, Lactobacillus sp. KY-107 was studied in shake flask culture using the modified MRS medium. Maximum mannitol production was obtained with fructose as the sole carbon source. Within 95 hours of incubation, a final concentration of 70g/L of mannitol from 100g/L fructose was obtained with an indicated yield of 86% based on fructose consumed. However, higher concentrations of fructose could not effectively be transformed to mannitol due to a lack of osmotolerance. The strain produced no other polyols such as glycerol and sorbitol as by-products. Yeast extract was best nitrogen source and high levels of inorganic phosphate up to 10g/L did not show any detrimental effect for mannitol formation. Manganese ion played important role in both cell growth and mannitol production. The optimum culture temperature and initial pH were $35^{\circ}C$ and 6-8, respectively.

• KSBB Journal
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• v.9 no.2
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• pp.140-146
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• 1994

Aureobasidium pullulans produced high concentration of polyols extracellularly in the media of sucrose, glucose and mannose as sole carbon source. Mannitol was the main polyol produced during the late exponential and stationary phases of growth together with small quantities of glycerol. Sucrose and glucose were rather rapidly metabolized to mannitol among carbon sources examined where the initial glucose concentration showed no difference in the amount of mannitol. In contrast 20%(w/v) of sucrose was the most appropriate concentration tested. However, the yield of mannitol based on substrate used($Y_{p/s}$) was independent on the initial concentration, and the mean value of mannitol yield in 10% glucose and sucrose media was 0.144 and 0.188, respectively. Mannitol production was reduced in response to an elevated water stress imposed by salts within the range from 0.25 to IM of NaCl or KCl as stress solutes. However, glycerol contents and its ratio to mannitol were increased at the conditions of high salinity. Based on the results, extracellular mannitol produced by A. pullulans probably resulted partly from osmoregulation(in case of glycerol) and mainly from, as known to occur in most of fungi, enzymatic reduction of the corresponding hexoses through phosphate pathway.

• Journal of Microbiology and Biotechnology
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• v.28 no.12
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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.

• Journal of Korean Neurosurgical Society
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• v.42 no.4
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• pp.337-341
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• 2007

Objective : Repeated administration of mannitol in the setting of large hemispheric infarction is a controversial and poorly defined therapeutic intervention. This study was performed to examine the effects of multiple-dose mannitol on a brain edema after large hemispheric infarction. Methods : A middle cerebral artery was occluded with the rat suture model for 6 hours and reperfused in 22 rats. The rats were randomly assigned to either control (n=10) or the mannitol-treated group (n=12) in which intravenous mannitol infusions (0.8 g/kg) were performed six times every four hours. After staining a brain slice with 2,3,5-triphenyltetrazolium chloride, the weight of hemispheres, infarcted (IH) and contralateral (CH), and the IH/CH weight ratio were examined, and then hemispheric accumulation of mannitol was photometrically evaluated based on formation of NADH catalyzed by mannitol dehydrogenase. Results : Mannitol administration produced changes in body weight of $-7.6{\pm}1.1%$, increased plasma osmolality to $312{\pm}8\;mOsm/L$. It remarkably increased weight of IH ($0.77{\pm}0.06\;gm$ versus $0.68{\pm}0.03\;gm$ : p<0.01) and the IH/CH weight ratio ($1.23{\pm}0.07$ versus $1.12{\pm}0.05$ : p<0.01). The photometric absorption at 340 nm of the cerebral tissue in the mannitol-treated group was increased to $0.375{\pm}0.071$ and $0.239{\pm}0.051$ in the IH and CH, respectively from $0.167{\pm}0.082$ and $0.162{\pm}0.091$ in the IH and CH of the control group (p<0.01). Conclusion : Multiple-dose mannitol is likely to aggravate cerebral edema due to parenchymal accumulation of mannitol in the infarcted brain tissue.

• Journal of Microbiology and Biotechnology
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• v.33 no.6
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• pp.780-787
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• 2023

Two mannitol producing lactic acid bacteria were isolated from pa (green onion)- kimchi, identified and named as Leuconostoc mesenteroides SKP 88 and Leuconostoc citreum SKP 92, respectively. Both isolates grew well at 25-30℃, initial pH 6-8, and 3% and lower NaCl concentration. Both isolates converted fructose into mannitol efficiently when grown on MRS broth containing fructose and glucose. Glucose was used as a carbon source and fructose was used as a precursor for mannitol. Mannitol yields were the highest in MRS broth with 3% fructose and 2% glucose. Shine muscat juice fermentation was done using each isolate as a starter. As fermentation progressed, decrease in pH and increases in titratable acidity and viable counts were observed. L. mesenteroides SKP 88 showed better mannitol conversion ability than L. citreum SKP 92, and shine muscat juice fermented with L. mesenteroides SKP 88 showed the mannitol production of 41.6 g/l at 48 h, and juice fermented with L. citreum SKP 92 showed 23.4 g/l at the same time. Yogurt fermentations showed similar patterns, and yogurt fermented with L. mesenteroides SKP 88 showed the mannitol production of 15.13 g/l. These results showed that both strains are useful as starters for healthy fermented foods with reduced fructose contents.

• KSBB Journal
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• v.11 no.2
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• pp.181-185
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• 1996

A considerable amounts of mannitol were accumulated during the fermentation of Kimchis. When several oligosaccharide including fructo-, soybean-, and isomaltooligosaccharides were added during the preparation of Kimchi as beneficial ingredient respectively, fructooligosaccharides (at $25^{\circ}C$) and soybean-oligosaccharides (at $35^{\circ}C$) significantly increased the amounts of mannitol accumulation, while isomalto-oligosaccharides exerted no effect at all fermentation conditions examined. This result were caused by no appearance of microorganisms which have the capability of utilizing isomalto-oligosacsharides during fermentation period. Isomalto-oligosaccharides can be recommended as an effective ingredient of Kimchis because both oligosaccharides and mannitol that have favorable functionalities were simultaneously contained. However, so as to enhance the cooling taste of Kimchis by increasing the content of mannitol, fructo- and soybean-oligosaccharides are rather favorable.

• Journal of Microbiology and Biotechnology
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• v.16 no.3
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• pp.484-486
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• 2006

Maltosyl (G2)-mannitol, produced by the transglycosylation of mannitol with maltotriose by Bacillus stearothermophilus maltogenic amylase, was not found to support lactic acid production by Streptococcus sobrinus NRRL 14555. Furthermore, the synthesis of water-insoluble glucans from maltosyl-mannitol by S. sobrinus NRRL 14555 was much lower than that from xylitol or mannitol. Consequently, these results suggest that maltosyl-mannitol could be used as a noncariogenic sugar substitute in food products.

• Journal of Microbiology and Biotechnology
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• v.11 no.5
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• pp.880-883
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• 2001

To optimize co-production of dextran and mannitol from sucrose by Leuconostoc mesenterides ATCC 13146, a batch culture fermentation was conducted by using various concentrations of sucrose and initial culture pHs. The production of dextran and mannitol showed a growth-associated pattern. The highest yields of both dextran and mannitol were obtained at pH 6.0 and $10\%$ (w/v) sucrose. They could be easily separated by using alcohol fractionation. Maximum yields of dexran and mannitol were 0.45 and 0.35 of the consumed sucrose, respectively. Overall productivities of dextran and mannitol were 1.47 and 0.37 g/l/h, respectively.

• Journal of Microbiology and Biotechnology
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• v.21 no.9
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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.