• Microbiology and Biotechnology Letters
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• v.44 no.1
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• pp.34-39
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• 2016

Wild-type yeast strains were isolated from nuruk, a type of microbial starter culture used for fermenting grains to produce alcoholic products, that was collected from different areas in Korea. Strains were identified based on the analysis of 18S rRNA sequences. Fifty strains shared the highest sequence similarity with Saccharomyces cerevisiae and were designated MBYK1-MBYK50. Among these S. cerevisiae isolates, MBYK45 produced $44.0{\pm}0.3g$ of ethanol from 200 g maltose after incubation at $30^{\circ}C$ for 48 h. Maximum ethanol production of $110.80{\pm}0.81g/l$ with productivity of $3.79{\pm}0.14g^{-1}l^{-1}h^{-1}$ was obtained at optimum culture conditions of pH (6.0), maltose (200 g/l), and temperature ($35^{\circ}C$). This study indicates that the MBYK45 strain of S. cerevisiae, isolated from nuruk, might be suitable for traditional liquor production from malts.

• KSBB Journal
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• v.21 no.2
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• pp.85-89
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• 2006

Typical property of the white-rot fungi is their ability to degrade lignin and other aromatic compounds with non-specific extracellular enzyme. In this work, the modification of the strain(Funalia trogii ATCC 200800) and the culture condition was performed to enhance enzyme productivity. Single cell was separated by the protoplasts formation and several putative laccase and manganese peroxidase inducers were tested. By adopting the modified strain, enzyme productivity increased comparing with that of the original strain. Extracellular enzyme formation was highly stimulated by the addition of copper and various aromatic compounds in the glucose-based culture medium.

• KSBB Journal
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• v.14 no.3
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• pp.380-383
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• 1999

During the biodesulfurization of dibenzothiophene to 2-hydroxybiphenyl by Rhodococcus erythropolis IGTS8, a surfactant-like substance was secreted into the medium resulting in the decrease of the surface tension of the medium. Due to the substance, the optical density (at 600 nm) of the medium had no co-relation with dry cell weight during cultivation. The growth rate of IGTS8 increased by the addition of 1 % Tween 80, but it was inhibited over Tween 80 concentration of 2 % (v/v).

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.05a
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• pp.367-370
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• 2005

본 연구는 김치에서 분리한 유산균과 starter를 첨가하여 제조한 김치의 항암효과가 in vitro 상에서 어떻게 나타나는지 알기위해 실시하였다. 유산균의 균체 자체로는 모든 암세포에 있어서 세포독성을 거의 나타내지 못하였으며, 김치액의 경우는 평균적으로 $30{\sim}40%$정도의 세포독성을 보여주었다. 김치액인 K2가 K1에 비하여 다소 높은 세포독성을 나타내어 첨가된 starter에 따라 약간의 차이를 보여주었다. 유산균의 파쇄액의 경우에는 모든 암세포에서 50%이상의 세포독성을 보였고 대장암 세포인 WiDr과 위암세포인 MKN-45에서 $70{\sim}80%$ 정도의 세포독성으로 암세포 성장 저해에 상당히 효과적으로 관찰되었다. 유산균의 종류에 따른 세포독성을 비교해보면, 혼합 균체 파쇄액인 E3가 단일 균체 파쇄액보다 전반적으로 약간 높은 경향을 보여주었다.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.263-268
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• 2004

Two species of halophilic bacteria were isolated from five salted seafoods and identified by 16S rDNA sequenc­ing homology. One was identified as Halomonas subglaciescola and other four strains were belong to Halomo­nas marina. The identity of all isolates with standard organisms was above $95\%.$ H. subglaciescola, H. marina IN, and H. marina SH-2 grew in salinity condition from $3%\;to\;18\%$ NaCl but growth of H. marina SQ and H. marina SH-l grew in salinity environment from $8\%\;to\;17\%.$ Maximum biomass of H. subglaciescola, H. marina IN, H. marina SQ, H. marina SH-1, and H. marina SH-2 growing in LB medium containing $15\%$ NaCl were about 3.2, 4.5, 4.5, 5.7, and 4.2, however the maximum biomass in LB medium containing $5\%$ NaCl were about 2.2, 1.1, 0.7, 0.2, and 2.4 as optical density at 660 nm, respectively. In scanning electron micrograph, unknown material (mucus) attached to outer membrane of all isolates was observed. When mucus isolated from halophilic bacterial cell was added to culture of E. coli, E. coli grew in medium containing $15\%$ NaCl.

• Korean Journal of Food Science and Technology
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• v.15 no.1
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• pp.46-50
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• 1983

Direct starch-utilizing microorganisms were isolated from 50 samples. Among them, Y-5 strain was selected as one of the potential microorganisms which could utilize starch directly to produce protein or lipid as food resources. The Y-5 strain was identified as a strain of Sporobolomyces holsaticus. It grew on starch or inulin better than on glucose of fructose and its composition was 45% of crude protein, 16% of crude lipid and 9.2% of ash.

• Microbiology and Biotechnology Letters
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• v.11 no.1
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• pp.33-38
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• 1983

As flocculent strains are likely to have considerable potential for internal cell recycle, kinetic studies on glucose medium with flocculent Saccharomyces uvarum were carried out in batch and continuous culture. Using a mathematical model, the kinetic parameters at each temperature and pH were estimated in order to establish optimal conditions. It was found that an overall optimum temperature for growth and ethanol production in the range 33-35$^{\circ}C$ was desirable. With regard to the effect of pH, ethanol production by S. uvarum was found to be relatively insensitive to pH value between 4 and 6, with an optimum pH of around 5. At these optimal conditions a maximum ethanol productivity of 12 g/$\ell$/h was determined using semi-batch process together with 5. uvarum.

• KSBB Journal
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• v.17 no.6
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• pp.555-559
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• 2002

Three different strains of Aureobasidium pullulans were grown in batch cultures to compare their abilities of enzyme production. It was found that specific enzyme activity was the highest with strain ATCC 9348 and the enzyme production was closely coupled to growth. Studies on morphology during the growth of A. pullulans revealed that mycelia cells were dominant at the initial stages of growth. However, yeast-like cells and chlamydospores were dominant in the latter stages of batch culture. The pattern of morphological changes during the growth period was not affected by pH. However, it appears that the ratio of intra- to extracellular enzyme activity tended to increase with fermentation time irrespective of the pH employed, suggesting that the secretion efficiency of intracellular enzyme to broth likely depends on cell morphology Using molasses as a cheap source of sucrose, enzymatic production of fructo-oligosaccharides as a feed additive with A. pullulans cells could be achieved successfully at 55$\^{C}$ and pH 5.5.

• Microbiology and Biotechnology Letters
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• v.45 no.2
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• pp.149-154
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• 2017

To increase the efficiency of esterase production by Bacillus, high cell-density culture of recombinant Escherichia coli through fed batch fermentation was tested. Cells were cultured to $OD_{600}$ of 76 (35.8 g/l DCW) with dissolved oxygen level controlled to least above 30% air saturation by supplying pure oxygen. Cells were cultured to an $OD_{600}$ of 90 (42.4 g/l DCW) with glucose feeding controlled to at least 1 g/l. However, the cells reached stationary phase at the late stage of culture, despite glucose being supplied. Cells were cultured to an $OD_{600}$ of 185 (87.3 g/l DCW) by supplying additional medium with fortified yeast extract. To increase the productivity of the recombinant protein, cell growth and esterase productivity based on induction time were evaluated. Late exponential phase induction for esterase production in fed batch fermentation resulted in maximum optical density $OD_{600}$ of 190 (89 g/l DCW) and maximum esterase activity of 1745 U/l, corresponding to a 5.8-fold enhancement in esterase production, compared to the early exponential phase induction. In this study, we established fermentation methods for achieving maximum production of Bacillus-derived esterase by optimizing IPTG induction time in high-cell density culture by supplying pure oxygen and a nitrogen source.

• KSBB Journal
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• v.19 no.4
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• pp.250-256
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• 2004

In this work we have cultivated several B. cereus strains in a complex LB medium in order to study the production of phospholipase C (PLC), and among them B. cereus 318 showed the highest productivity of PLC. Some components, i.e., 5 g/L glucose, 5 g/L yeast extract, 5 g/L peptone, 0.5∼1.0 g/L K$_2$HPO$_4$, 0.02∼0.04 g/L ZnSO$_4$$.$7H$_2$O and 3 g/L NaHCO$_3$ were found to be optimal for the high production of PLC by B. cereus 318. Optimal culture temperature and pH were found to be 30$^{\circ}C$ and pH 7.5 for the PLC production, respectively. Optimum reaction temperature and pH of the PLC produced by B. cereus 11 and 318 were 45$^{\circ}C$ and pH 4.0, while they were 50$^{\circ}C$ and pH 7.0 for the PLC by B. cereus 559. The PLC produced by B. cereus was activated by Mn$\^$2+/, Co$\^$2+/ and dimethyl sulfoxide (DMSO), but its activity was inhibited by Cu$\^$2+/ and partially by glycerol, isopropanol and sodium dodecyl sulfate (SDS).