• Journal of Applied Biological Chemistry
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• v.63 no.4
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• pp.429-437
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• 2020

This study aimed to investigate the change in physicochemical properties and lactic acid bacterial communities during kimchi fermentation at different temperatures (8, 15, and 25 ℃) using two molecular genetics approaches, multiplex polymerase chain reaction and 16S rRNA gene sequencing. The pH during fermentation at 8, 15, and 25 ℃ decreased from 6.17 on the initial fermentation day to 3.92, 3.79, and 3.48 after 54, 30, and 24 days of fermentation, respectively, while the acidity increased from 0.24% to 1.12, 1.35, and 1.54%, respectively. In particular, the levels of lactic acid increased from 3.74 g/L on the initial day (day 0) to 14.43, 20.60, and 27.69 g/L during the fermentation after 24, 18, and 12 days at 8, 15, and 25 ℃, respectively, after that the lactic acid concentrations decreased slowly. The predominance of lactic acid bacteria (LAB) in the fermented kimchi was dependent on fermentation stage and temperature: Lactobacillus sakei appeared during the initial stage and Leuconsotoc mesenteroides was observed during the optimum-ripening stage at 8, 15, and 25 ℃. Lac. sakei and Lactobacillus plantarum grew rapidly in kimchi produced at 8, 15, and 25 ℃. In addition, Weissella koreensis first appeared at days 12, 9, and 6 at 8, 15, and 25 ℃ of fermentation, respectively. This result suggests that LAB population dynamics are rather sensitive to environmental conditions, such as pH, acidity, salinity, temperature, and chemical factors including free sugar and organic acids.

• Microbiology and Biotechnology Letters
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• v.24 no.6
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• pp.726-732
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• 1996

To improve the fermentation characteristics(such as starch-degradability, ethanol tolerance, sugar and high-temperature tolerance) of recombinant haploid yeast Saccharomyces diastaticus K114, hybridization technique was used. The hybridization partner was S. diastaticus 1177 which had good glucoamylase activity and fermentabi- lity. The best hybrid HH64 showed improved ethanol tolerance, sugar and high-temperature tolerance. Especia- lly, the starch-fermentability was significantly improved, since the hybrid produced 1.60% (w/v) ethanol from 4% (w/v) starch, while the recombinant haploid K114 produced 1.30% (w/v) ethanol. The optimum temperature and pH for the starch-fermentation by the hybrid HH64 was 30$\circ$C and 5, respectively. The hybrid yeast HH64 produced 7.5% (w/v) ethanol directly from 20% (w/v) starch.

• Journal of Environmental Health Sciences
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• v.27 no.4
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• pp.79-83
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• 2001

The sludge wastes fermentation process reactors were operated to produce the VFAs(volatile fatty acids) as supplemental carbon sources and to determine the optimum operating conditions. The experiment was carried out by varied mixture ration of 400:0 350:30 300:100 200:200 and operating temperature 2$0^{\circ}C$ 3$0^{\circ}C$ and 4$0^{\circ}C$ The results were as follows: Higher VFAs production rate observed at higher mixed ratio of primary sludge. When the mixed ratio of primary sludge and return sludge were 400:0 350:50 300:100 200:200 respectively. VFAs production are were 829.6mg/l 944.2 mg/l 597.9mg/ml an d441.6 mg/l , respectively. the yield of VFAs increased with temperature, but decreased with initial TSS concentration Because fermented sludge has relatively low nitrogen and phosphorus and relatively high VFAs it can be used as a substitute for external carbon in biological nutrient removal process.

• YAKHAK HOEJI
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• v.39 no.1
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• pp.24-30
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• 1995

Lectin from mistletoe(Viscum coloratum) fermented by Lactobacillus plantarum was compared with the lectin from unfermented mistletoe. Agglunating activity of fermented mistletoe was stable at pH 3.77~8.71, at temperature range of $0~40^{\circ}C$ and in the presence of 9 mental ions, which results are similar to unfermented one, but less stable at pH 2.03~3.00 and more stable at temperature $60~80^{\circ}C$ than lectin from unfermented one. Agglunating activity of lectin from mistletoe fermented for 1 or 2 days and from fraction number 42~54 was not inhibited by all sugars used except for lectin from fraction number 21~34. Mitogenic activity to murine lymphpocytes of lectin from mistletoe was decreased by fermentation process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.4
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• pp.631-635
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• 1995

In order to develop effective manufacturing method and to improve quality of low-salt fermented squid(10% of table salt), we investigated the effects of temperature, salinity and pH on the growth of Staphylococcus xylosus, Micrococcus varians, Pseudomonas diminuta and Pseudomonas D2 isolated from of low-salt fermented squid and the growth characteristics of these bacteria during fermentation were elucidated. All bacteria showed good growth during the process of low-salt fermented squid(pH 6~7 ; concentration of NaCl, 7~10% ; temperature, 7~1$0^{\circ}C$) and their cell numbers increased as fermentation proceeded under the same fermentation condition.

• Journal of Microbiology and Biotechnology
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• v.2 no.1
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• pp.26-34
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• 1992

The effect of induction temperature on fermentation parameters has been investigated extensively using Escherichia coli M5248[pNKM21], a producer of recombinant human interleukin-2 (rhIL-2). In this recombinant microorganism, the gene expression of rhIL-2 is regulated by the cI857 repressor and $P_L$ promoter system. The recombinant fermentation parameters studied in this work include the cell growth, protein synthesis, cell viability, plasmid stability, $\beta$-lactamase activity, and rhIL-2 productivity. Interrelationships of such fermentation parameters have been analyzed through a quantitative assessment of the experimental data set obtained at eight different culture conditions. While the expression of rhIL-2 gene was repressed at culture temperatures below $34^\circ{C}$ with little effect on other fermentation parameters, under the conditions of rhIL-2 production $>(36~44^\circ{C})$ the cell growth, plasmid stability, and $\beta$-lactamase activity were, as induction temperature was increased, more profoundly reduced. Although the rhIL-2 content in the insoluble protein fraction was maximum at $40^\circ{C}$, total rhIL-2 production in the culture volume was found to be highest at the induction temperature of $36^\circ{C}$. This was in contrast to the previously known optimum induction temperature of the P$_{L}$ promoter system $>(40~42^\circ{C})$.Explanations for such a discrepancy have been proposed based on a product formation kinetics, and their implications have been discussed in detail.l.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.4
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• pp.59-67
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• 1988

Anaerobic digestion at the temperature of $35-55^{\circ}C$ was conducted using an artificial sludge of uniform composition. The hydraulic retention time of 5 days was chosen because the temperature effect was effectively shown at a high loading. Inhibition of the methane fermentation decreased as the temperature increased. Acid fermentation was prevalent at the mesophilic and intermediate temperatures, while active methane fermentation took place at $55^{\circ}C$. Temperature not only affects activity of the microorganisms, but also affects physical and chemical properties of the sludge, Digestion inhibition was much reduced when the feed sludge was diluted, and active methane fermentation was possible at all temperatures. The digestion efficiency was governed by the organic loading rate as well as the hydraulic 10ading rate. No reduction of the digestion efficiency at $40-45^{\circ}C$, which had been referred to a critical temperature range, was observed. The digestion efficiency increased monotonically from mesophilic to thermophilic range. Improved settling properties of digested sludge was also recorded at higher temperatures.

• Korean Journal of Food Science and Technology
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• v.21 no.3
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• pp.331-337
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• 1989

In order to investigate the method for extension of shelf-life of Kimchi, the effect of low temperature heating and addition of mustard oil on pH and total acidity of Kimchi during storage at $15^{\circ}C$ were studied. Mustard oil was found to have the antimicrobial effect on the major lactic acid bacteria of Kimchi such as Lactobacillus plantarum, Lactobacillus brevis, Leuconostoc mesenteroides and Pediococcus cerevisiae, Addition of 200p.p.m. mustard oil, 0.1% mustard powder and 0.01% $H_2O_2$ to Kimchi effectively reduced the fermentation rate of Kimchi. Low temperature heating of salted cabbage and addition of 200p·p.m. mustard oil and 0.01% $H_2O_2$ to seasonings extented the time reaching optimum ripening of Kimchi about 2.5 times longer than control. Combination of low temperature heating, addition of mustard oil and $H_2O_2$ to seasonings and post low temperature heating delayed fermentation time Kimchi about 5 times longer than control after 15 days storage at $15^{\circ}C$.

• Food Science and Preservation
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• v.16 no.6
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• pp.804-809
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• 2009

Recently, many Koreans have started to consume aged kimchi fermented long-term at low temperatures. In the present study, the effect of low temperature ($5^{\circ}C$) on pH, titratable acidity (TA), organic acid level, viable microbial cell count, amino acid concentration, and polygalacturonase activity (PG) during long-term fermentation (46 weeks) of kimchi, were evaluated. After 10 weeks of fermentation, kimchi had a pH of 4.1 and a TA of 1.0%, respectively after 46 weeks fermentation, these values were 3.9 and 1.3%, respectively. Lactic acid, the ratio of lactic acid to acetic acid, and the ratio of Lactobacillus species/Leuconostoc species in kimchi increased as fermentation progressed from 10 weeks to 46 weeks. However, total viable cell counts of aerobic bacteria, yeasts, Lactobacillus species, and Leuconostoc species, free amino acid levels, and PG decreased as the fermentation period was extended from 10 weeks to 46 weeks.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.292-297
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• 1996

In this study, biochemical changes of muscle protein in squid Sikhae prepared at various temperatures and moisture content were investigated. The pH values in squid Sikhae decreased rapidly with increase in titratable acidity during fermentation at high temperature and moisture content. Growth rate of lactic acid bacteria increased rapidly during fermentation at high temperature and moisture content. Changes in muscle protein subunit were analyzed by SDS-PAGE; myosin heavy chain component disappeared completely during preparation of squid Sikhae and actin component decreased slowly during fermentation. Therefore, it was suggested that myosin heavy chain component in squid muscle protein was autolyzed at the incipient for-mentation time and actin component was degraded by acidic protease in muscle and protease produced from microorganisms during fermentation.