• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.299-306
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• 2005

Anaerobic fermentation of food waste (FW) and waste activated sludge (WAS) for hydrogen production was performed in CSTR (Continuous Stirred tank reactor) under various HRTs and volumetric mixing ratio (V/V) of two substrates, FW and WAS. The specific hydrogen production potential of FW was higher than that of WAS. However, pH drop in the CSTR for hydrogen production from FW was higher than that from WAS. The maintenance of desired pH during fermentative hydrogen production is regarded as the most important operation parameter for the stable hydrogen production. Therefore, when the potential of hydrogen production from FW and better buffer capacity of WAS, the proper mixture of FW and WAS for fermentative hydrogen production were considered as a useful complementary substrate. The maximum yield of specific hydrogen production, 140 mL/g VSS, was found at HRT of 2 day and the volumetric mixing ratio of 20:80 (WAS : FW). The spatial distribution of hydrogen producing bacteria was observed in anaerobic fermentative reactor using fluorescent in situ hybridization (FISH) method.

• Transactions of the Korean hydrogen and new energy society
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• v.15 no.3
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• pp.187-193
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• 2004

In this study, Anaerobic sewage sludge in a batch reactor operation at $35^\circ{C}$ was used as the seed to investigate the effect of pretreatments of waste activated sludge and to evaluate its hydrogen production potential by anaerobic fermentation. Various pretreatments including physical, chemical and biological means were conducted to utilize for substrate. As a result, SCODcr of alkali and mechanical treatment was 15 and 12 times enhanced, compared with a supernatant of activated sludge. And SCODcr was 2 time increase after re-treatment with biological hydrolysis. Those were shown that sequential hybridized treatment of sludge by chemical & biological methods to conform hydrogen production potential in bath experiments. When buffer solution was added to the activated sludge, hydrogen production potential increased as compare with no addition. Combination of alkali and mechanical treatment was higher in hydrogen production potential than other treatments.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.1
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• pp.15-18
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• 1998

The entanol productivity of superoxide dismutase (SOD)-deficient mutants of Saccharo-Myces cerevisiae was examined under the oxidative stress by Paraquat. It was observed that MnSOD-deficient mutant of S. cerevisiae had higher ethanol productivity than wild type or CuZnSOD-deficient yeast both in aerobic and in anaerobic culture condition. Pyruvated dehydrogenase activity decreased by 35% and alcohol dehydrogenase activity increased by 32% were observed in MnSOD-deficient yeast grown aerobically. When generating oxygen radicals by Paraquat, the ehanol productivity was increased by 40% in CuZnSOD-deficient or wild strain, resulting from increased activity of alcohol dehydrogenase and decreased a activity of pyruvate dehydrogenase. However, the addition of ascorbic acid with Paraquat returned the enzyme activities at the level of control. These results imply that SOD-deficiency in yeast strains may cause the metabolic flux to shift into anaerobic ethanol fermentation in order to avoid their oxidative damages by Paraquat.

• Journal of Nutrition and Health
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• v.28 no.9
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• pp.834-845
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• 1995

This study was conducted in order to establish an in vitro method simulating the physiological function of fibers along the large intestine of humans. Commercial fibers including guar gum, apple pectin, citrus pectin, CM-cellulose, alginic acid and $\alpha$-cellulose, and dietary fiber residues obtained from rice bran, barley, soybean, Korea cabbage, apple, tangerine and sea mustard were employed to determine the water-holding capacity, weight of hydrated residue and fiber content after anaerobic fermentation using human fecal inoculum for 24 hours, followed by dialysis under osmotic suction pressure. The weight of hydrated residue in commercial fibers was in the decreasing order of CM-cellulose > alginic acid, $\alpha$-cellulose > apple pectin, citrus pectin > guar gum and that in food fiber residues was in the decreasing order of rice bran, sea mustard > soybean > tangerine, Korean cabbage > barley > apple. It was demonstrated that the larger the weight of hydrated residue was, the more the weight of human stool increased. Consequently this in vitro method can be used as a preceeding test before undertaking animal or human experiment to predict the physiological effects of fiber residues from diverse food samples as well as commercially refined fibers.

• Microbiology and Biotechnology Letters
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• v.8 no.2
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• pp.135-142
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• 1980

The process of biological treatment of organic wastewater is principally associated with those of self-purification in the natural water environment. The treatment system has e intensive function of stabilizing wastewater more effectively than in natural water, which is like natural water concentrated in a small space. Biological treatment of wastewater involves activated sludge and various modified process, trickling filter, rotating disk, oxidation ditch, etc. for aerobic decomposition and anaerobic processes such as anaerobic decomposition and methane fermentation. The basic characteristic of these processes is the use of mixed culture for the conversion of pollutants. This review forcuses on the various kinds of microorganisms related to each treatment processes. Kinetic analysis of the activated sludge process is discussed in order to understand the basis of control and maintenance of the biological treatment process.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.05a
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• pp.137-140
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• 2003

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.3
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• pp.473-474
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• 1989

• Microbiology and Biotechnology Letters
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• v.20 no.4
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• pp.430-436
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• 1992

Hydrogen evolution by mixed fermentation of Clostn"dium butyn"cum and photosynthetic bacteria which were capable of consuming clostridial metabolites and evolving hydrogen was investigated. Acetate and butyrate formed from anaerobic clostridial fermentation were efficiently utilized by Rhodopseudomonas sPhaeroides K-7. For complete bioconversion of clostridial metabolites such as acetate and butyrate into hydrogen, mixed culture of both anaerobic organisms forming molecular hydrogen was performed. By the mixed culture, the yield of hydrogen production increased by 20 to 75% and the levels of clostridial metabolites such as acetate, butyrate decreased in the fermentation broth. Influence of cell mixing ratio. mixing time and inoculum level on hydrogen evolution by mixed culture were examined. And then cometabolic pattern compared with in pure culture was observed as time course.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.1
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• pp.10-16
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• 2013

Characteristics of biological hydrogen production rate and organic acid under anaerobic fermentation process were investigated with sugar wastewater. Hydrogen production rate was higher with alkaline pre-treatment than acidic pre-treatment, resulting in 70% increment. An adequate supply of the nutrients (N or P) into raw sugar wastewater could increase hydrogen production rate. Carbohydrate degradation of the anaerobic fermentation process was not directly related with hydrogen production. Sugar wastewater with the addition of the nutrients shows 3 times higher B/A ratio than the raw sugar wastewater. B/A ratio of the wastewater with alkaline pre-treatment and nutrients addition was most higher than other samples, showing 4.02 of B/A ratio. Higher B/A ratio shows higher hydrogen production rate at each sample.

• Journal of Animal Environmental Science
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• v.4 no.2
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• pp.167-174
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• 1998

It is known that the anaerobic fermentation of organic matter (OM) is divided into 2 phases, acidogenic phase in which OM is digested into volatile fatty acid (VFA), and methanogenic phase where the produced VFA is converted to CH4 and CO2. In a natural fermenting procedure, these 2 phases occur at the same time. However the total production of end products (methane) may be limited if these 2 phases occur at the same time. This is believed to be due to the difference in growth rate, substrate-utilizing efficiency and favorable environment for each microbes (acidogens and methanogens), involved in each phase. It is therefore suggested for the maximum recycling of organic waste (such as animal waste) through providing 2 different steps in fermenting procedure, acidogenic phase and methanogenic phase, in each case the activity of involved microbes can be maintained at the maximum level. The results obtained from these experiments are summarized as follows : The loading rates of swine waste were made through 2.5, 5 and 10 gVS / l / d to identify its acidogenic fermenting character in this study. The VFA yield was maximized at 10 gVS / l / d of loading rate. On the basis of this study was executed to identify the optimum HRT of 1, 2 and 4 days at 10 gVS / l / d of loading rate in acidogenic phase. The maximum VFA yield was obtained at 1 days of HRT.