• KSBB Journal
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• v.10 no.2
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• pp.170-175
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• 1995

The effect of nitrogen source on production of a high viscosity exopolysaccharide, methylan, from methanol by Mentylobacterium organophilum was investigated in fed-batch culture. During the fermentation, cells continued to grow even after the nitrogen source added to the medium was depleted and methylan production was stimulated under the condition which ammonium ion was depleted. Cell growth increased proportionally to the initial concentration of ammonium ion in the medium, but methylan production was significantly inhibited at the high concentration of ammonium ion. As the initial concentration of ammonium ion increased, the specific growth rate, the specific product formation rate and the specific substrate consumption rate decreased due to the inhibitory effect of excess ammonium ions. In order to reduce the inhibitory effect by high concentration of ammonium ion. The control of ammonium ion concentration within the desired level(usually $0.45g/\ell$) was necessary. When ammonium ion concentration was maintained below $0.15g/\ell$ by exponential feeding, methylan production could be increased up to $12.5g/\ell$.

• Korean Journal of Environmental Agriculture
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• v.18 no.1
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• pp.54-60
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• 1999

Three different types of lab-scale anaerobic bioreactors, AF and two-stage ASBF-PR and ASBF-SP, were evaluated in treating swine wastewater by operating at $1{\sim}2$ days of hydraulic retention time with increasing organic loading rate upto 6.3 $kg-COD/m^3{\cdot}d$ at $35^{\circ}C$. Seeding the anaerobic bioreactors with waste anaerobic digester sludge from a municipal wastewater treatment plant was effective and a 40-day acclimation period was required for steady-state operation. Three anaerobic bioreactors were effective in treating swine wastewater with COD removal efficiency of $66.4{\sim}84.9$% and biogas production rate of $0.333{\sim}0.796m^3/kg-COD_{removed}{\cdot}d$. Increases of organic loading rate by increasing influent COD concentration and/or decreasing hydraulic retention time caused decreases in COD removal efficiency and increases in biogas production rate. At relatively high organic loading rate employed in this study, the treatment efficiency of AF and ASBF-PR were similar but superior than that of ASBF-SP, indicating that porosity and pore size of the media packed in the bioreactors are more important factors contributing the performance of to bioreactors than specific surface area of the media. TKN in swine wastewater must be removed prior to the anaerobic processes when anaerobic process is considered as a major treatment process since influent TKN concentration of $1,540{\sim}1,870mg/L$ to the bioreactors adversely affect the activity of methanogenic bacteria, resulting in decreases of treatment efficiency and biogas production rate by 50%.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.2
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• pp.93-101
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• 2000

The objective of this study was to evaluate the possibility of co-digestion of food waste and sewage sludge mixture using anaerobic system. The Biochemical methane Potentials of cabbage and food waste were $297ml\;CH_4/g$ VS and $306.7ml\;CH_4/g$ VS, respectively. The biodegradability of food waste was 60%. The concentrations of acetate, propionate, and isobutyrate produced during the aerobic acidogenesis of food waste for 36 hours were 7,000~7,200 ppm, 260~280 ppm, 380~400 ppm, and 40~50 ppm, respectively, of which acetate was over 85%. The concentrations of acetate, propionate, and isobutyrate produced during the anaerobic acidogenesis for 36 hours were 1,400~1,600 ppm, 30~40 ppm, 220~250 ppm, and 260~300 ppm, respectively, of which acetate was over 70%. The biodegradabilities of aerobic and anaerobic acidogenesis were 30% and 25%, respectively. Methanogensis could be activated under 1 % of NaCl and 1,000 ppm of volatile fatty acids at the range of pH 6.8~7.2. The maximum mixture ratio of food waste and sewage sludge in the present study was 2:8 by the result of VS removal rate and Methane production.

• KSBB Journal
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• v.22 no.2
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• pp.97-101
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• 2007

This study was performed to examine the availability of anaerobic digestion of the remainders caused by bacterial cellulose production process using food wastes. They maybe to be considered as others second pollution sources. Thus, this study was targeted to minimize content of organic material and to obtain more energy in those remnants using two-phase UASB reactor. The working volume of first hydrolysis fermentor was 35 L (total 55 L) and the second methane fermentor was 40 L (total 50 L). The organic loading rate of hydrolysis fermentor was 3 g-VS/L${\cdot}$day and 25,000 ppm of $COD_{cr}$ for methane fermentor. The hydraulic retention time was 18 days for hydrolysis reactor and 33 days for methane reactor. The hydrolysis reactor and methane reactor were performed at 35, 40$^{\circ}C$ respectively. For the efficient stable performance, the composition of organic wastes at each stage was as follow; Food waste with bacterial culture remnants (1 : 1), bacterial cellulose remnants, bacterial cellulose culture remnants with food wastes saccharified solids (1 : 1). When the anaerobic digestion was performed stably at each stage, the COD removal efficiency was 88, 90, 91 % respectively. At this time, methane production rate was 0.26, 0.34, $0.32m^3\;CH_4/kg-COD_{remove}$. As well as the values of anaerobic digestion at third stage were more higher than values of anaerobic digestion using food wastes. It is clearly to say that the food wastes zero-emission system constructed in our lab is more efficient way to treat and reclaim food wastes.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2127-2131
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• 2008

본 연구는 자연생태하에서 지속가능한 태양에너지와 생태계작용에 의한 수질개선기법을 개발하기 위하여 생태연못을 설치하여 수질부하가 발생함에 따라 생태연못에 에너지를 순환시켜 생태적 수질정화 기능을 강화하는데 목적을 두었다. 본 연구에서 생태연못(Eco-Pond) 시스템의 수질개선 원리는 수중(유입수)의 침전, 유기산 생성, 메탄 발효, 호기성 산화, 광합성 산소배출 및 병원균 제거 등을 촉진시키기 위한 목적으로 축산농가 및 마을단위의 축산 및 생활하수 유입부에서 생태연못을 두어 수질을 개선하는 공법 즉, 산화조(Oxidation Pond)에 SolaBee 시스템을 결합한 모델을 제안하였다. 에너지 순환장치를 이용한 수질개선 방안으로는 태양열 연못 내에 물순환장치를 만들어 수체를 효율적으로 순환시키고 공기를 혼합시켜 부영양화가 진행되는 연못이 수질을 자연친화적으로 개선시키도록 하였다. 따라서 연구결과 태양에너지는 다른 자연에너지(풍력 등)에 비해서 에너지 밀도는 낮지만 지역의존성이 적고 그 양이 방대하여 21세기 중요한 에너지원으로 사용가능성을 확인할 수 있었다. 본 연구에서 제시된 에너지 순환구조를 가진 생태연못 시스템은 우리나라 중소규모의 농촌 및 축산농가에 보급 될 수 있는 수질개선 시스템이다.

• Journal of Environmental Health Sciences
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• v.23 no.3
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• pp.40-49
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• 1997

In Korea, naked barley and tapioca are main raw materials for the production of fermentation ethyl alcohol, and one million drums bf 95% fermentation ethyl alcohol is produced per year by use of them. Stillage of alcoholic fermentation is mostly digested by methane fermentation process, and methane gas occured if methane fermentation process is recovered and mixed with fuel to decrease 25-30% for total fuel used in factories. In the anaerobic digestion process of naked barley stillage, supplement of nutrients is necessary to slove the problems caused by inhibitory materials contained if stillage and deficiency of nutrients. Therefore, the objective of this study was to examine why the anaerobic digesters using the naked barley distillery wastewater have shown the poor digestability frequently and how to control it. As the poor digestion was supposed to be occurred by the lack of iron as trace nutrient, the experiments were carried out to find out the optimum dosage and the way of addition of iron and to assess the quantitative evaluation of the type of iron in digesters. Initially, bottle test as batch digesters and lab-scaled continuous flow digesters were used in order to determine the digestion characteristics with tapioca and naked barley distillery wastewater. According to the results of batch tests, the poor digestion was caused by volatile fatty acids and could be improved by adding of calcium. The activity of the methanogenic bacteria were increased remarkably when the iron was added to the digester in the form of mixture with substrates.

• Korean Journal of Organic Agriculture
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• v.27 no.4
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• pp.529-540
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• 2019

The present study investigated the effect of forage sources and their inclusion levels in diet on the rumen fermentation of Korea traditional goat. Timothy and alfalfa were used as forage sources. Forages were mixed with concentrate diet in different ratios. The ratios of forage to concentrate diets were varied to 1:9, 5:5 and 9:1. The rumen fluid of goat was gathered from slaughter house. Dry matter digestibility was decreased and methane production was increased as forage levels in diet was increased. When forage sources, timothy and alfalfa, were compared, groups with timothy showed greater methane production than the groups of alfalfa. Molar ratio of produced acetate and valerate were increased when forage level in diet was increased. In the case of propionate and butyrate, they were decreased as elevated forage levels in diet. The result of this study provided a basic information for rumen fermentation of Korean traditional goat and these information could be applied in the development of nutritional and feeding strategy.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.3
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• pp.38-49
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• 2010

The technology of anaerobic digestion of organic wastes has been researched for the production of biogas in various purposes. Biogas comes from anaerobic digestion and landfill in which that of main components are methane and carbon dioxide containing small amount of hydrogen sulfide and ammonia. Biogas can either be used directly on the site where it is generated after proper upgrading or distributed to external customer via separate pipelines like natural gas. There are four basic ways biogas can be utilized such as production of heat and steam, electricity production, vehicle fuel and production of chemicals. There is no international technical standard for biogas use but some countries have developed national standards and procedures for biogas use. In this paper, technical standards of biogas depending on purpose have reviewed for the several countries.

• Journal of agriculture & life science
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• v.45 no.3
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• pp.69-79
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• 2011

This study was conducted to estimate effects of by-products of medical herbs replacing rice straw on in vitro fermentation characteristics. Each trial was composed of five treatments including medical herbs : rice straw (%) = 20 : 80 (T1), 40 : 60 (T2), 50 : 50 (T3), 100 : 0 (T4) and the control. Each treatment had eight fermentation times (3, 6, 9, 12, 24, 36, 48 and 72 hours) with three replications. The gas production and DM degradation were significantly (P<0.05) increased by supplementation, especially T4, during the whole fermentation periods. Methane production increased along with addition of by-products similar to the gas production and DM degradation. The pH values ranged from 5.39 to 6.80 and were significantly (P<0.05) decreased by supplementation of by-products of medical herbs. Microbial growth rates reached the peak at between 36 and 48h, thereafter tended to decrease. Although there were no significant differences in the enzyme activities, there was a tendency of increase in T4 treatment. From above results, the replacement levels, particularly 100% replacement of rice straw by by-products of medical herbs, resulted in improving the in vitro fermentation characteristics such as increasing gas production, microbial growth and DM degradation. Also it may help digestion by increasing enzyme activities.

• Journal of Life Science
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• v.28 no.10
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• pp.1244-1253
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• 2018

Rumen microbiome consists of a wide variety of microorganisms, such as bacteria, archaea, protozoa, fungi, and viruses, that are in a symbiotic relationship in a strict anaerobic environment in the rumen. These rumen microbiome, a vital maker, play a significant role in feed fermentation within the rumen and produce different volatile fatty acids (VFAs). VFAs are essential for energy metabolism and protein synthesis of the host animal, even though emission of methane gas after feed fermentation is considered a negative indicator of loss of dietary energy of the host animal. To improve rumen microbial efficiency, a variety of approaches, such as feed formulation, the addition of natural feed additives, dietary feed-microbes, etc., have taken to increase ruminant performance. Recently with the application of high-throughput sequencing or next-generation sequencing technologies, especially for metagenomics and metatranscriptomics of rumen microbiomes, our understanding of rumen microbial diversity and function has significantly increased. The metaproteome and metabolome provide deeper insights into the complicated microbial network of the rumen ecosystem and its response to different ruminant diets to improve efficiency in animal production. This review summarized some recent advances of rumen microbiome techniques, especially "meta-omics," viz. metagenomic, metatranscriptomic, metaproteomic, and metabolomic techniques to increase feed fermentation and utilization in ruminants.