• The Korean Journal of Mycology
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• v.36 no.1
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• pp.93-97
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• 2008

A $Ca^{2+}-independent$ microbial transglutaminase (mTGase) from the actinomycete Streptomyces mobaraensis IFO13819 is a useful enzyme in the food industry. It is consists 406 amino acid residues, which comprised leader and pro region of 75 amino acid residues and the structure region of 331 amino acid residues. Pro and structure gene of TGase were cloned into the yeast shuttle vector pYAEG-TER and then used to transform Saccharomyces cerevisiae 2805. Expression of mTGase in recombinant was confirmed with Northern hybridization and the maximal activity of TGase was shown 26 mU/ml.

• Journal of Microbiology and Biotechnology
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• v.4 no.3
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• pp.215-221
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• 1994

Two strains of yeast (RA-74-2 and RA-912) showing superior fermenting ability at a high temperature were isolated from soils and wastewaters by an enrichment culture method. Based on the morphological and physiological charateristics, the two strains were identified as Saccharomyces cerevisiae and Kluyveromyces marxianus, respectively. RA-74-2 was able to grow upto $43^{\circ}C$ and sustain similar fermenting ability in the temperatures range from 30 to $40^{\circ}C$. In addition, the sugar- and ethanol-tolerance of RA-74-2 were 30% (w/v) glucose and 10% (v/v) ethanol, which appeared to be higher than those of nine other industrial yeast strains currently being used in the alcohol factories. The thermotolerant ethanol fermenting yeast RA-912 showed identical growth in the temperatures range from 35 to $45^{\circ}C$ and was resistant to various heavy metals. The quality and quantity of byproducts of the isolated yeast strains in fermentation broth after fermentation at $40^{\circ}C$ and $45^{\circ}C$ were similiar with those obtained at $30^{\circ}C$. These results show that RA-74-2 can be adopted for the ethanol fermentation process where the expenses for cooling system is significant, and suggest that RA-912 may be applied in either SSF(simultaneous saccharification and fermentation) or Flash-fermentation process and RA-912 may be used as a gene donor for the development of thermotolerant ethanol-fermenting yeasts.

• Microbiology and Biotechnology Letters
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• v.25 no.3
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• pp.258-265
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• 1997

The effects of medium pH and culture temperature on the expression and secretion of inulinase and invertase were investigated with recombinant Saccharomyces cerevisiae cells. These cells were obtained by transformation of 2$\mu$-based plasmids pYI10 and pYS10 which contain Kluyveromyces marxianus inulinase gene (INU1A) and S. cerevisiae invertase gene (SUC2), respectively, in the downstream of GAL1 promoter. The expression level and localization of inulinase and invertase were not affected significantly by the initial medium pH: secretion efficiencies of inulinase and invertase into the medium were about 90% and 60%, respectively, in the pH ranges of 4.0 to 6.5. However, the expression and secretion of both enzymes were strongly dependent on the culture temperature. The highest expression (7.7 units/mL) and secretion (6.7 units/mL) of inulinase were observed at 28$\circ$C and 30$\circ$C. As a consequence of decreased localization of inulinase in the periplasmic space, the secretion efficiency increased from 68% at 20$\circ$C, to 95% at 35$\circ$C,. The total expression level and secretion efficiency of invertase increased from 19 units/mL and 55% at 20$\circ$C to 25 units/mL and 68% at 35$\circ$C, respectively. Irrespective of the culture temperature, the invertase activity in the cellular fraction (periplasmic space and cytoplasmic fractions) was kept constant at around 33-45%.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.1
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• pp.49-55
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• 2001

For the production of probiotic feed enriched with viable yeasts, aerobic liquid culture of Kluyveromyces marxianus was attempted in pulverized residual food wastes. After the preliminary shaking culture result, the liquid food wastes was added with urea($0.5g/{\ell}$), o-phosphate($0.4g/{\ell}$ ), molasses($4g/{\ell}$), and yeast extract($1g/{\ell}$), and the fermentation was carried out in 2-litre jar fermenter. In 12 hours of aerobic mixed culture with Aspersillus oryzae, viable cell count of the yeast reached to the number of $1.4{\times}10^{10}/{\ell}$ in the cultured medium.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.10a
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• pp.306-309
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• 2005

본 연구는 기능성 발효유로서 티벳산 발효유에서 분리한 효모(Kluyveromyces marxianus)와 유산균(Lactobacillus bulgaricus)의 혼합스타터를 이용한 발효유를 제조하여 배양 기간별 균수측정, pH, 적정산도, Alcohol 함량, 항암활성에 대해 알아보았다. 배양은 산도 0.68%, 최종 pH가 4.5가 되는 시점에서 마치게 되는데 이때의 배양 온도는 $30^{\circ}C$, 배양기간은 36시간이었다. 이때의 균수는 K. marxianus는 $5.3{\times}10^9$) CFU/mL, L. bulgaricus는 $3.2{\times}10^9$ CFU/mL였고 Alcohol 함량은 0.35%까지 증가하였다. 36시간 배양하여 제조된 발효유의 항종양 활성은 Hep-2에 대해서는 90.5%, HEC-1B는 86.6%, SW-156은 60.3%, SK-MES-1은 57.14%의 높은 항종양활성을 나타내었다. 이상의 결과 기존의 유산균 발효유에 효모를 첨가한 알코올 발효유의 제조가 가능하며, 제품의 항종양 활성의 측면에서도 높은 기능성을 나타내는 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• v.22 no.5
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• pp.642-648
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• 2012

We determined the nucleotide sequence of the URA3 gene encoding orotidine-5'-phosphate decarboxylase (OMPDCase) of the erythritol-producing osmotolerant yeast Candida magnoliae by degenerate polymerase chain reaction and genome walking. Sequence analysis revealed the presence of an uninterrupted open-reading frame of 795 bp, encoding a 264 amino acid residue protein with the highest identity to the OMPDCase of the yeast Kluyveromyces marxianus. Phylogenetic analysis of the deduced amino acid sequence revealed that it shared a high degree of identity with other yeast OMPDCase homologs. The cloned URA3 gene successfully complemented the ura3 null mutation in Saccharomyces cerevisiae, revealing that it encodes a functional OMPDCase in C. magnoliae. An enzyme activity assay and reverse transcription polymerase chain reaction indicated that the expression level of the C. magnoliae URA3 gene in S. cerevisiae was not as high as that of the S. cerevisiae URA3 gene. The GenBank accession number for C. magnoliae URA3 is JF521441.

• Microbiology and Biotechnology Letters
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• v.16 no.4
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• pp.265-269
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• 1988

For the purpose of developing new thermotolerant yeast strains for ethanol fermentation, yeasts were isolated from molasses and screened for their fermentation ability at elevated temperatures. Three candidate strains were screened. These strains preferred pH 5.0 and 34$^{\circ}C$ for their ethanol production. Under such conditions the three strains showed average ethanol productivity of 75g ethanol per liter of fermentation broth in n synthetic medium containing glucose as substrate. These strains were identified as Saccharomyces cerevisiae and Kluveromyces marxianus.

• Journal of Dairy Science and Biotechnology
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• v.35 no.3
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• pp.169-175
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• 2017

Recently, the health-promoting effects of functional foods have been shown to prevent nutrition-related diseases, improve physical and mental well-being, satisfy hunger, and provide necessary nutrients for the human body. Koumiss is a common type of fermented mare's milk that has been shown to have beneficial therapeutic effects on cardiovascular disease, tuberculosis, and diarrhea as it can nourish vessels, relieve ill mood, and improve digestion. Hence, in this study, we aimed to prepare health-promoting koumiss using different concentrations of flaxseed (Linum usitatissimmum L.), which has the potential to control heart disease, hypertension, inflammation, and lung function. The pH was decreased to around 4.42-4.43, whereas the total anthocyanin (TA) content was increased to around 0.78~0.82% after fermentation of the koumiss premix. There were no significant differences in pH and TA among the three groups, including the control group. In sensory profile analysis, the taste, flavor, color, texture, and overall acceptability decreased in proportion to the added amount of flaxseed. These findings provided the first data describing the effects of flaxseed on koumiss fermentation, establishing a basis for commercial-scale production of koumiss containing fermented flax seed and for improving the health-promoting activity of koumiss.

• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.129-133
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• 1990

The strain of Nuruk yeat No. 15 (NY-15) which ferments lactose in milk was Isolated from Nuruk and identified as Saccharomyces marxianus according to the API 20C profile index. The lactose hydrolysing ability of NY-15 was similar to that Saccharomyces fragilis ATCC 8583 which has ${\beta}-galactosidase$ activity. Its optimum growth temperature, pH and time for the production of maximum enzyme activity showed $28^{\circ}C$, 4.5 and 28hr, respectively. Galactose as well as sucrose as carbon sources, and urea as nitrogen source Increased the production of enzyme. In order to test the production of alcohol, NY-15 was inoculated in whey medium and whey medium added with sugar. In the former, NY-15 produced 2% alcohol and in the latter, it showed 12% alcohol production. The optimal medium pH for lactose hydrolysis of NY-15 is 4.5, whereas that of Saccharomyces fragilis ATCC 8583 is 3.5

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.4
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• pp.99-104
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• 2001

The influence of agitation speed on the yeast growth was investigated in the production of probiotic feed from pulverized liquified food wastes by aerobic fermentation. A yeast Kluyvermyces marxianus was selected through a preliminary screening. The yeast was cultured by 2liter jar fermenter. in 10% solid(w/v) substrate of liquified food waste at $35^{\circ}C$ with each different agitation speed of 500, 900 and 1200 rpm. For the acceleration of enzyme excretion mixed culture with Aspergillus oryzae was also attempted and the results were compared to those of single culture. As results the viable cell number was increased by increasing agitation speed. But it showed highest value in 900rpm and then decreased in 1200rpm. The mixed culture increased amylase activity and growth rate, but did not seem to enhance the highest viable cell count in the final fermentation stage.