• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.914-918
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• 2004

This study was carried out to analyze the metabolic flux of W. kimchii sk10 on pyruvate and ethanol as a carbon source. The sk10 grown on ethanol produced acetate under aerobic conditions rather than under anaerobic conditions. The lactate and acetate were produced on ethanol plus pyruvate by the sk10 grown under aerobic and anaerobic conditions, respectively. The resting cell of sk10 produced 99.1 mM acetate and 17.3 mM lactate under aerobic conditions and 51.1 mM acetate and 62.4 mM lactate under anaerobic conditions from ethanol plus pyruvate, respectively. This result is thought to be due to the difference in the $NADH/NAD^+$ ratio depending on the growth conditions. The 11-fold overproduction of NADH peroxidase results in a low $NADH/NAD^+$ratio under aerobic growth conditions. At the low $NADH/NAD^+$ ratio, the metabolic flux of pyruvate toward lactate has to be shifted to a flux toward acetate without NADH oxidation to $NAD^+$, and ethanol oxidation to acetate coupled to $NAD^+$ reduction to NADH has to be activated.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.4 no.1
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• pp.33-40
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• 1997

The microbial growth of fresh, vacuum packaged, cook-in-bag uncured beef patties was determined in two film structures, a commercial (PE/EVOH), and super barrier ($SiO_2$ coated polyester) material. Packaged samples were cooked to internal temperature of 71 and $82^{\circ}C$ for 30 minutes, and stored in temperature abused ($23{\pm}2^{\circ}C$) and refrigerated storage ($4-6^{\circ}C$). Barrier properties had a significant effect (p<0.001) on aerobic and mesophilic growth in the abused condition. Cooking temperatures had a statistically significant effect (p<0.05) on aerobic growth in the refrigerated condition. The growth of anaerobes and psychrophiles were not significantly effected by either variables. Storage times had the most significant effect (p<0.001) for all groups of microorganisms. The physical properties of the commercial film (strength, thickness, and shrinkage) were changed after exposure to thermal treatment, while the super barrier package had actually no change.

• Journal of Microbiology and Biotechnology
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• v.25 no.7
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• pp.1114-1118
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• 2015

Microbial fuel cells (MFCs) have gathered attention as a novel bioenergy technology to simultaneously treat wastewater with less sludge production than the conventional activated sludge system. In two different operations of the MFC and aerobic process, microbial growth was determined by the protein assay method and their biomass yields using real wastewater were compared. The biomass yield on the anode electrode of the MFC was 0.02 g-COD-cell/gCOD-substrate and the anolyte planktonic biomass was 0.14 g-COD-cell/g-COD-substrate. An MFC without anode electrode resulted in the biomass yield of 0.07 ± 0.03 g-COD-cell/g-CODsubstrate, suggesting that oxygen diffusion from the cathode possibly supported the microbial growth. In a comparative test, the biomass yield under aerobic environment was 0.46 ± 0.07 g-COD-cell/g-COD-substrate, which was about 3 times higher than the total biomass value in the MFC operation.

• Korean journal of food and cookery science
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• v.18 no.5
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• pp.516-521
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• 2002

This study was investigated to prove the relation between the ingredient of Samul Chol-Pyon and its microorganism pollution level during the storage. As a result, the pollution degree in total aerobic bacteria, yeast, mold, and colitis germs of rice power turned out to have a lower one than the oriental medicine materials do. In case of preserved write Chol-Pyon, the total aerobic bacteria pollution level was 8.8 $\times$ 10$^3$CFU/g the highest degree among other ones in their among other ones in their early pollution levels and in the oriental medicine materials, the pollution level was degreased as its annex increased. Moreover, yeast propagated fast in its first day of storage, but mold grew somewhat slowly than yeast and total aerobic bacteria did. In every case, the range of colitis germs growth was between 10$^2$-10$^3$CFU/g and it was similar to the each one of total aerobic bacteria, yeast, and molds. On its third day of storage, the pollution level of mold showed 10$^4$-10$\^$5/CFU/g.

• Environmental Engineering Research
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• v.10 no.6
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• pp.265-268
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• 2005

A batch-type study was conducted to investigate the phosphorus release and uptake under anaerobic and aerobic conditions according to organic loading changes. As organic loading increased, anaerobic P release increased but aerobic P uptake decreased. Where organic carbon contents remain high in aerobic conditions, PHB consumption within the microbial cells diminished, therefore it was found that in order to enhance P uptake rate, it should reach the endogenous growth stage where the entire organic loading was consumed.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.1
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• pp.90-96
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• 2008

In order to meet the stringent requirement of sludge disposal and to find ecological alternative, aerobic digestion coupled with alkaline pretreatment was studied. The treated sludge was tested for the potential of liquid fertilizer. In the aerobic digestion, it was obvious that the performance of digester B(fed with the sludge pretreated by NaOH) was better than that of digester A(fed with raw sludge) in terms of COD and SS removal. SS and VSS removal rates in digester B were 66% and 69%, respectively. At 5 days, TSS removal rate reached 47% in the digester B, which was 71% of final TSS removal rate. It revealed that the pretreatment process can shorten the retention time of aerobic digestion. 94.1% of TCOD in the raw sludge was reduced by alkaline pretreatment and aerobic digestion. Final SCOD was in the range of 220$\sim$230 mg/L implying the sludge was stabilized. Nitrification and pH drop were observed in the aerobic digestion. Final nitrate concentrations in digester A and B were 445.4 and 223.1 mg/L and final pH in digester B was 3.0. Biological assays reported that leaf size of cucumber seedling increased with nitrate concentration and sludge to soil ratio. The sludge treated by alkaline and aerobic digestion promoted the growth of seedling leaf and stem remarkably compared to raw sludge. In contrast, the aerobically digested sludge without pretreatment improved leaf growth and inhibited stem growth.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.4
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• pp.457-468
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• 2013

Based on the activated sludge model(ASM), a mathematical model which represents the aerobic sludge digestion by sequencing batch reactor(SBR) combined with ultrasonic treatment was composed and performed in this study. Aerobic digestion using sequencing batch reactor(SBR) equipped with ultrasound treatment was also experimented for the purpose of parameter calibration. Most of the presented kinetic parameters in ASM or ASM2 could be used for the aerobic digestion of sludge but the parameters related in hydrolysis and decay rate needed modification. Hydrolysis rate constant of organic matter in aerobic condition was estimated at $0.3day^{-1}$ and the maximum growth rate for autotrophs in aerobic condition was $0.618day^{-1}$. Solubilization reactions of particulate organics and nitrogen by ultrasonication was added in this kinetic model. The solubilization rate is considered to be proportional to the specific energy which is defined by specific ultrasound power and sonication time. The solubilization rate constant by ultrasonication was estimated at $0.202(W/L)^{-1}day^{-1}$ in this study. Autotrophs as well as heterotrophs also decomposed by ultrasonic treatment and the nitrification reaction was limited by the lack of autotrophs accumulation in the digester.

• Food Science of Animal Resources
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• v.36 no.6
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• pp.752-759
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• 2016

The objective of this study was to describe the growth patterns of Staphylococcus aureus in combinations of NaCl and $NaNO_2$, using a probabilistic model. A mixture of S. aureus strains (NCCP10826, ATCC13565, ATCC14458, ATCC23235, and ATCC27664) was inoculated into nutrient broth plus NaCl (0, 0.25, 0.5, 0.75, 1, 1.25, 1.5, and 1.75%) and $NaNO_2$ (0, 15, 30, 45, 60, 75, 90, 105, and 120 ppm). The samples were then incubated at 4, 7, 10, 12 and $15^{\circ}C$ for up to 60 d under aerobic or vacuum conditions. Growth responses [growth (1) or no growth (0)] were then determined every 24 h by turbidity, and analyzed to select significant parameters (p<0.05) by a stepwise selection method, resulting in a probabilistic model. The developed models were then validated with observed growth responses. S. aureus growth was observed only under aerobic storage at $10-15^{\circ}C$. At $10-15^{\circ}C$, NaCl and $NaNO_2$ did not inhibit S. aureus growth at less than 1.25% NaCl. Concentration dependency was observed for NaCl at more than 1.25%, but not for $NaNO_2$. The concordance percentage between observed and predicted growth data was approximately 93.86%. This result indicates that S. aureus growth can be inhibited in vacuum packaging and even aerobic storage below $10^{\circ}C$. Furthermore, $NaNO_2$ does not effectively inhibit S. aureus growth.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.6
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• pp.816-826
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• 2015

The present experiment evaluated the influence of moisture level and anaerobic fermentation on aerobic stability of total mixed ration (TMR). The dynamic changes in chemical composition and microbial population that occur after air exposure were examined, and the species of yeast associated with the deterioration process were also identified in both non-fermented and fermented TMR to deepen the understanding of aerobic deterioration. The moisture levels of TMR in this experiment were adjusted to 400 g/kg (low moisture level, LML), 450 g/kg (medium moisture level, MML), and 500 g/kg (high moisture level, HML), and both non-fermented and 56-d-fermented TMR were subjected to air exposure to determine aerobic stability. Aerobic deterioration resulted in high losses of nutritional components and largely reduced dry matter digestibility. Non-fermented TMR deteriorated during 48 h of air exposure and the HML treatment was more aerobically unstable. On dry matter (DM) basis, yeast populations significantly increased from $10^7$ to $10^{10}cfu/g$ during air exposure, and Candida ethanolica was the predominant species during deterioration in non-fermented TMR. Fermented TMR exhibited considerable resistance to aerobic deterioration. Spoilage was only observed in the HML treatment and its yeast population increased dramatically to $10^9cfu/g$ DM when air exposure progressed to 30 d. Zygosaccharomyces bailii was the sole yeast species isolated when spoilage occurred. These results confirmed that non-fermented and fermented TMR with a HML are more prone to spoilage, and fermented TMR has considerable resistance to aerobic deterioration. Yeasts can trigger aerobic deterioration in both non-fermented and fermented TMR. C. ethanolica may be involved in the spoilage of non-fermented TMR and the vigorous growth of Z. bailii can initiate aerobic deterioration in fermented TMR.

• Journal of Environmental Science International
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• v.14 no.10
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• pp.955-963
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• 2005

From sludge of S municipal wastewater treatment plant in Busan, Korea, we isolated the denitrifier DN-9 which showed the ability of denitrification under aerobic conditionby the color change and gas formation in liquid culture with Giltay medium. The isolated strain was identified as Pseudomonas sp. DN-9 on the basis of the morphological, physiological, biochemical and nucleotide sequence analysis of l6S rRNA. The isolated strain, Pseudomonas sp. DN-9, has cytochrome $cd_1$, nirS of nitrite reductase. By the co-existance of additional ammonium and nitrate ion, the strain was not affected largely on growth in SL series broth. It seemed the result of denitrification. Although Pseudomonas sp. DN-9 has a good nitrate reduction activity under aerobic condition, the activity is less than Pseudomonas stutzeri in same cultivation condition. However, Escherichia coli had little the activity of aerobic denitrification and Pseudomonas putida showed lower activity of aerobic denitrification than Pseudomonas sp. DN-9 and Pseudomonas stutzeri in this study.