• Transactions of the Korean hydrogen and new energy society
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• v.25 no.4
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• pp.337-343
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• 2014

This study was conducted to evaluate the characteristics of dark fermentative $H_2$ production from microalgae (Chlorella vulgaris) using batch reactors under mesophilic (25, $35^{\circ}C$) and thermophilic (45, $55^{\circ}C$) conditions. The $H_2$ yield and $H_2$ production rate increased with increasing temperature. The maximum $H_2$ yield and $H_2$ production rate were 56.77 mL $H_2/g$ dcw, 3.33 mL $H_2/g\;dcw{\cdot}h$ at $55^{\circ}C$, respectively. The activation energy calculated using Arrhenius equation was 36.24 kcal/mol, which was higher than that of dark $H_2$ fermentation of glucose by anaerobic mixed culture. Although the concentration of butyrate was maintained, the concentrations of lactate and acetate increased with increasing temperature. The $H_2$ yield was linearly proportional to acetate/ butyrate ratio.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.674-680
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• 2015

This study was conducted to characterize the rapidly processed salt-fermented sandfish sauce added Bacillus coagurance KM-1 (RSSS) and commercial salt-fermented sandfish sauce (CSSS 1, 2). Contents of total nitrogen and amino nitrogen were higher in CSSS 1,2 than in RSSS (P<0.05). Total free amino acid contents of RSSS and CSSS 1,2 were 1,121.2±100 mg/100 g, 1,553.6±98.2 mg/100 g and 1,507.3±99.8 mg/100 g. Major free amino acid of RSSS was glutamic acid (194.4±17.3 mg/100 g), alanine (140.8±12.6 mg/100 g), lysine (135.1±12.1 mg/100 g), leucine (109.8±9.8 mg/100 g), aspartic acid (103.0±9.2 mg/100 g), valine (73.5±6.6 mg/100 g) in ordor. The samples were caused by their composition of the free amino acids rations, in which were umami, sweet and bitter taste in the salt-fermented sandfish sauce during fermentation. The Na was the largest mineral followed by K, Mg, P, Ca in the samples (P<0.05). Sensory evaluation result of samples, CSSS 1 was the highest than the others in overall acceptance.

• Korean Journal of Environmental Agriculture
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• v.25 no.3
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• pp.247-256
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• 2006

This study has been conducted for the process of food wastes disposal using surplus capacity of established sewage treatment plant by co-digestion of fermented food wastes and sewage sludge after thermophilic acid fermentation of food wastes. The co-digestion of thermophilic acid fermented food wastes and sewage sludge was performed by semi-continous method in mesophilic anaerobic digestion reactor. It showed great digestion efficiency as the average SCOD and VS removal efficiency in organic loading rate 3.30g VS/L.d. were 74.2% and 73.6%, and the gas production rate and average methane content were 0.440 L/g $VS_{add}.d$ and 66.5%, respectively. Based on the results of this study, the co-digestion of thermophilic acid fermented food wastes and sewage sludge in sewage treatment plant is able to improve treatment efficiency of anaerobic digestion reactor and to dispose food wastes simultaneously, and was proved excellent economical efficiency comparing with any other treatment methods.

• Mycobiology
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• v.30 no.4
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• pp.228-232
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• 2002

This study focused on the production of high quality compost for the growth of aero-thermophilic fungi, which has a promoting effect on the growth rate and production of oyster mushrooms. The automated solid-state bioreactor system was designed on the basis of a Three-Phase-One system, which controls the serial steps of prewetting, pasteurization and fermentation processes. High numbers of thermophilic fungi and bacteria were recovered from the mushroom composts prepared by this solid-state bioreactor. The rates of composting process were depended on physical as well as chemical factors. Among these factors, the parameters of moisture content and temperature were found to be particularly important. In our automated system, constant levels of moisture content, temperature and ventilation via mixing were provided by a centralized control apparatus including PLC, water tank and water jacket systems. These features induced higher microbiological activity of aero-thermophiles.

• Environmental Engineering Research
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• v.12 no.4
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• pp.129-135
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• 2007

This study evaluated microbial risk that could develop within soil microbial communities after amended with organic fertilizers from stabilized swine manure waste. For this purpose, we assessed the occurrences and competitiveness of antibiotic resistance and pathogenicity in soil microbial communities that were amended with swine manure wastes stabilized by a traditional lagoon fermentation process and an autothermal thermophilic aerobic digestion process, respectively. According to laboratory cultivation detection analysis, soil applications of the stabilized organic fertilizers resulted in increases in absolute abundances of antibiotic resistant bacteria and of two tested pathogenic bacteria indicators. The increase in occurrences might be due to the overall growth of microbial communities by the supplement of nutrients from the fertilizers. Meanwhile, the soil applications were found to reduce competitiveness for various types of antibiotic resistant bacteria in the soil microbial communities, as indicated by the decrease in relative abundances (of total viable heterotrophic bacteria). However, competitiveness of pathogens in response to the fertilization was pathogens-specific, since the relative abundance of Staphylococcus was decreased by the soil applications, while the relative abundance of Salmonella was increased. Further testes revealed that no MAR (multiple antibiotic resistance) occurrence was detected among cultivated pathogen colonies. These findings suggest that microbial risk in the soil amended with the fertilizers may not be critical to public health. However, because of the increased occurrences of antibiotic resistance and pathogenicity resulted from the overall microbial growth by the nutrient supply from the fertilizers, potential microbial risk could not be completely ruled out in the organic-fertilized soil samples.

• Korean Journal of Food Science and Technology
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• v.38 no.3
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• pp.419-426
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• 2006

A thermophilic microorganism, strain JE 375, which produces a thermostable protease, was isolated from soil and compost in Korea. This gram-positive, rod-shaped, catalase positive, motility positive, and hemolysis ${\beta}$ containing organism was implicated in glucose fermentation, mannitol fermentation, xylose oxidation, aerobic activity and spore formation. The color of the colony was yellowish white. The temperature range for growth at pH 6.5 was between 55 and $70^{\circ}C$, with an optimum growth temperature of $65^{\circ}C$. This result confirmed the strain JE 375 as a thermophilic microorganism. The enzyme was produced aerobically at $65^{\circ}C$ during 20 hr in a medium (pH 6.5) containing 1% trypton. 1% maltose, 0.5% yeast extract and 1% NaCl. The 16S rDNA of strain JE 375 had 97.6% sequence similarity with the 16S rDNA of Bacillus caldoxyloyticus. On the basis of biochemical and physiological properties and phylogenetic analysis, we named the isolated strain as Bacillus sp. JE 375. The thermostable protease from Bacillus sp. JE 375 had been partially purified and characterized. The molecular weight of the enzyme was deduced from SDS-PAGE and gel chromatography as 55 kDa and its optimal temperature was $60^{\circ}C$. The enzyme showed its highest activity at pH 7.5 and was stable from pH 7.0 to 8.0.

• Journal of Life Science
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• v.7 no.1
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• pp.30-38
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• 1997

For screening thermostable $\alpha$-amylase from thermophiles, various samples from extreme environments such as hot spring and sewage near them, and compoat, wereexamined microbial growth in enrichment culture medium at 55$\circ$C on the assumption that enzymes from thermophiles are inevitable thermostable. One strain showing higher $\alpha$-amylase activity was pure cultured and designated as Bacillus sp. TR-25 from the results of morphological, cultural and physiological characteristics. The most important carbon sourses for the enzyme production were soluble starch, dextrin, potato starch and corn starch. Glucose and fructose had a catabolite repression on the enzyme production. The good nitrogen sources for the enzyme production were yeat extract, nutrient broth, tryptone, corn steep liquor and ammonium sulfate. The enzyme production was accelerated by addition of CaCl$_{2}$. $\cdot $ H$_{2}$O. The optimal medium composition for the enzyme production was soluble starch 2.0%, yeast extract 0.55, CaCl$_{2}$ $\cdot $ 2H$_{2}$O 0.015, Tween 80 0.001%, pH8.0, respectively. In jar fermenter culture, this strain shows a rapid growth and required cheaper carbon and nitrogen source. These properties are very useful to fermentation industry. The $\alpha$-amylase of this strain demonstrated a maximum activity at 80$\circ$C, pH 5.0, respectively. And calcium ion did not improve thermostability of the enzyme. At 10$0^{\circ}C$, this enzyme has 235 of relative activity. Transformation was carried out by thermophilic Bacillus sp. TR-25 genomic DNA. As a result, the transformant has increased thermostable $\alpha$-amylase activity.

• 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.

• Journal of Microbiology and Biotechnology
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• v.2 no.4
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• pp.293-296
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• 1992

Increased concentrations of yeast extract led to increased growth yields and faster growth rates of the newly isolated Clostridium thermobutyricum. This species produced butyrate as its main fermentation product from glucose as well as from yeast extract. In the presence of peptone or tyrptone and during growth on agar, up to 70% of the cells sporulated. Growth yields were 30 and 55 g per mole glucose in the presence of 0.05 and 2.0% yeast extract, respectively. The Arrhenius graph was biphasic, exhibiting an intermediary plateau around $38^{\circ}C$ with a concomitant change in the Arrhenius energy. The optimum temperature was $55^{\circ}C$. An unusually sharp decline in the growth rate occurred above $59^{\circ}C$ .

• Environmental Engineering Research
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• v.20 no.2
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• pp.121-125
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• 2015

Biohydrogen production from food waste via dark fermentation was conducted by using mixed culture under various environmental conditions (initial pH, initial F/M ratio, initial ferrous iron ($Fe^{2+}$), and temperature condition) in batch reactor. The results revealed that the maximum hydrogen yield of $46.19mL\;H_2/g\;COD_{add}$ was achieved at the optimal conditions (initial pH 8.0, initial F/M ratio 4.0, initial iron concentration 100 mg $FeSO_4/L$ and thermophilic condition ($55{\pm}1^{\circ}C$)). Furthermore, major volatile fatty acid (VFA) productions of butyrate (765.66 mg/L) and acetate (324.69 mg/L) were detected and COD removal efficiency was detected at 66.00%. Therefore, these optimal conditions could be recommended to operate a system.