• Animal Bioscience
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• v.37 no.2
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• pp.161-172
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• 2024

For sustainable development, better performance, and less gas pollution during rumen fermentation, there is a need to find a green and safe feed additive for ruminants. Cysteamine (CS) is a biological compound naturally produced in mammalian cells. It is widely used as a growth promoter in ruminants because of its ability to control hormone secretions. It mainly controls the circulating concentration of somatostatin and enhances growth hormone production, leading to improved growth performance. CS modulates the rumen fermentation process in a way beneficial for the animals and environment, leading to less methane production and nutrients loss. Another beneficial effect of using CS is that it improves the availability of nutrients to the animals and enhances their absorption. CS also works as an antioxidant and protects the cells from oxidative damage. In addition, CS has no adverse effects on bacterial and fungal alpha diversity in ruminants. Dietary supplementation of CS enhances the population of beneficial microorganisms. Still, no data is available on the use of CS on reproductive performance in ruminants, so there is a need to evaluate the effects of using CS in breeding animals for an extended period. In this review, the action mode of CS was updated according to recently published data to highlight the beneficial effects of using CS in ruminants.

• Journal of Ecology and Environment
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• v.47 no.4
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• pp.264-271
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• 2023

Environmental crises caused by climate change and human-induced disturbances have become urgent challenges to the sustainability of human beings. These issues can be addressed based on a data-driven understanding and forecasting of ecosystem responses to environmental changes. In this study, we introduce a long-term ecological monitoring system in Korean Long-Term Ecological Research (KLTER), and a plan for the Korean Ecological Observatory Network (KEON). KLTER has been conducted since 2004 and has yielded valuable scientific results. However, the KLTER approach has limitations in data integration and coordinated observations. To overcome these limitations, we developed a KEON plan focused on multidisciplinary monitoring of the physiochemical, meteorological, and biological components of ecosystems to deepen process-based understanding of ecosystem functions and detect changes. KEON aims to answer nationwide and long-term ecological questions by using a standardized monitoring approach. We are preparing three types of observatories: two supersites depending on the climate-vegetation zones, three local sites depending on the ecosystem types, and two mobile deployment platforms to act on urgent ecological issues. The main observation topics were species diversity, population dynamics, biogeochemistry (carbon, methane, and water cycles), phenology, and remote sensing. We believe that KEON can address environmental challenges and play an important role in ecological observations through partnerships with international observatories.

• Journal of the Korea Organic Resources Recycling Association
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• v.32 no.1
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• pp.13-19
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• 2024

The objective of this study was to assess the feasibility of a landfill project aimed at reducing greenhouse gas (GHG) from Puerto Cortes Landfill in Honduras ("Project"). The feasibility study involved surveying the status, composition and amount of waste entering the landfill, and projecting GHG emissions from the landfill. A projection of the GHG emissions with the IPCC model and based on the survey results indicated that the period 2027 to 2041 would see a total GHG emission reduction of 506,835 ton-CO₂/year, with a mean yearly GHG emission reduction of 33,789 ton-CO₂, assuming landfill gas collection is implemented, The findings of the study are expected to serve as basic data for deciding about whether and how to proceed with the Project.

• Animal Bioscience
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• v.37 no.3
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• pp.405-418
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• 2024

In recent years, there has been a growing argument attributing the primary cause of global climate change to livestock industry, which has led to the perception that the livestock industry is synonymous with greenhouse gas (GHG) emissions. However, a closer examination of the global GHG emission by sector reveals that the energy sector is responsible for the majority, accounting for 76.2% of the total, while agriculture contributes 11.9%. According to data from the Food and Agriculture Organization of the United Nations (FAO), the total GHG emissions associate with the livestock supply chain amount to 14.5%. Within this, emissions from direct sources, such as enteric fermentation and livestock manure treatment, which are not part of the front and rear industries, represent only 7%. Although it is true that the increase in meat consumption driven by global population growth and rising incomes, has contributed to higher methane (CH₄) emissions resulting from enteric fermentation in ruminant animals, categorizing the livestock industry as the primary source of GHG emissions oversimplifies a complex issue and disregards objective data. Therefore, it may be a misleading to solely focus on the livestock sector without addressing the significant emissions from the energy sector, which is the largest contributor to GHG emissions. The top priority should be the objective and accurate measurement of GHG emissions, followed by the development and implementation of suitable reduction policies for each industrial sector with significant GHG emissions contributions.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.666-671
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• 2012

Gas hydrates are inclusion compounds formed when small-sized guest molecules are incorporated into the well defined cages made up of hydrogen bonded water molecules. Since large masses of natural gas hydrates exist in permafrost regions or beneath deep oceans, these naturally occurring gas hydrates in the earth containing mostly $CH_4$ are regarded as future energy resources. The heat of dissociation is one of the most important thermal properties in exploiting natural gas hydrates. The accurate and direct method to measure the dissociation enthalpies of gas hydrates is to use a calorimeter. In this study, the high pressure micro DSC (Differential Scanning Calorimeter) was used to measure the dissociation enthalpies of methane, ethane, and propane hydrates. The accuracy and repeatability of the data obtained from the DSC was confirmed by measuring the dissociation enthalpy of ice. The dissociation enthalpies of methane, ethane, and propane hydrates were found to be 54.2, 73.8, and 127.7 kJ/mol-gas, respectively. For each gas hydrate, at given pressures the dissociation temperatures which were obtained in the process of enthalpy measurement were compared with three-phase (hydrate (H) - liquid water (Lw) - vapor (V)) equilibrium data in the literature and found to be in good agreement with literature values.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.2
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• pp.57-65
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• 2008

Wastewater containing strong organic matter is very difficult to treat by utilizing general sewage treatment plant. but the wastewater is adequate to generate biomass energy (bio-gas; methane gas) by utilizing anaerobic digestion. EcoDays Plug Flow Reactor (E-PFR), which was already proved as an excellent aerobic wastewater treatment reactor, was adapted for anaerobic food wastewater digestion. This research was performed to improve the efficiency of bio-gas production and to optimize anaerobic wastewater treatment system. Food wastewater from N food waste treatment plant was applied for the pilot scale experiments. The results indicated that the efficiency of anaerobic wastewater treatment and the volume of bio-gas were increased by applying E-PFR to anaerobic digestion. The structural characteristics of E-PFR can cause the high efficiency of anaerobic treatment processes. The unique structure of E-PFR is a diaphragm dividing vertical hydraulic multi-stages and the inversely protruded fluid transfer tubes on each diaphragm. The unique structure of E-PFR can make gas hold-up space at the top part of each stage in the reactor. Also, E-PFR can contain relatively high MLSS concentration in lower stage by vertical up-flow of wastewater. This hydraulic flow can cause high buffering capacity against shock load from the wastewater in the reactor, resulting in stable pH (7.0~8.0), relatively higher wastewater treatment efficiency, and larger volume of bio-gas generation. In addition, relatively longer solid retention time (SRT) in the reactor can increase organic matter degradation and bio-gas production efficiency. These characteristics in the reactor can be regarded as "ideal" anaerobic wastewater treatment conditions. Anaerobic wastewater treatment plant design factor can be assessed for having 70 % of methane gas content, and better bio-gas yielding and stable treatment efficiency based on the results of this research. For example, inner circulation with generated bio-gas in the reactor and better mixing conditions by improving fluid transfer tube structure can be used for achieving better bio-gas yielding efficiency. This research results can be used for acquiring better improved regenerated energy system.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.6
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• pp.823-829
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• 2016

Eight Holstein steers ($216{\pm}48kg$ body weight) fitted with ruminal and duodenal cannulas were used to evaluate effects of wheat straw processing (ground vs pelleted) at two straw inclusion rates (7% and 14%; dry matter basis) in dry rolled or steam-flaked corn-based finishing diets on characteristics of digestion. The experimental design was a split plot consisting of two simultaneous $4{\times}4$ Latin squares. Increasing straw level reduced ruminal (p<0.01) and total tract (p = 0.03) organic matter (OM) digestion. As expected, increasing wheat straw level from 7% to 14% decreased (p<0.05) ruminal and total tract digestion of OM. Digestion of neutral detergent fiber (NDF) and starch, per se, were not affected (p>0.10) by wheat straw level. Likewise, straw level did not influence ruminal acetate and propionate molar proportions or estimated methane production (p>0.10). Pelleting straw did not affect ($p{\geq}0.48$) ruminal digestion of OM, NDF, and starch, or microbial efficiency. Ruminal feed N digestion was greater (7.4%; p = 0.02) for ground than for pelleted wheat straw diets. Although ruminal starch digestion was not affected by straw processing, post-ruminal (p<0.01), and total-tract starch (p = 0.05) digestion were greater for ground than for pelleted wheat straw diets, resulting in a tendency for increased post-ruminal (p = 0.06) and total tract (p = 0.07) OM digestion. Pelleting wheat straw decreased (p<0.01) ruminal pH, although ruminal volatile fatty acids (VFA) concentration and estimated methane were not affected ($p{\geq}0.27$). Ruminal digestion of OM and starch, and post-ruminal and total tract digestion of OM, starch and N were greater (p<0.01) for steam-flaked than for dry rolled corn-based diets. Ruminal NDF digestion was greater (p = 0.02) for dry rolled than for steam-flaked corn, although total tract NDF digestion was unaffected (p = 0.94). Ruminal microbial efficiency and ruminal degradation of feed N were not affected (p>0.14) by corn processing. However, microbial N flow to the small intestine and ruminal N efficiency (non-ammonia N flow to the small intestine/N intake) were greater (p<0.01) for steam-flaked than for dry rolled corn-based diets. Ruminal pH and total VFA concentration were not affected ($p{\geq}0.16$) by corn processing method. Compared with dry rolled corn, steam-flaked corn-based diets resulted in decreased acetate:propionate molar ratio (p = 0.02). It is concluded that at 7% or 14% straw inclusion rate, changes in physical characteristics of wheat straw brought about by pelleting negatively impact OM digestion of both steam-flaked and dry-rolled corn-based finishing diets. This effect is due to decreased post-ruminal starch digestion. Replacement of ground straw with pelleted straw also may decrease ruminal pH.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.1
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• pp.82-89
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• 2009

Two in vitro experiments were conducted to examine the effects of propionate precursors in the dicarboxylic acid pathway on ruminal fermentatation characteristics, $CH_4$ production and degradation of feed by rumen microbes. Fumarate or malate as sodium salts (Exp. 1) or acid type (Exp. 2) were added to the culture solution (150 ml, 50% strained rumen fluid and 50% artificial saliva) to achieve final concentrations of 0, 8, 16 and 24 mM, and incubated anaerobically for 0, 1, 3, 6, 9 and 12 h at $39^{\circ}C$. For both experiments, two grams of feed consisting of 70% concentrate and 30% ground alfalfa (DM basis) were prepared in a nylon bag, and were placed in a bottle containing the culture solution. Addition of fumarate or malate in both sodium salt and acid form increased (p<0.0001) pH of culture solution at 3, 6, 9 and 12 h incubations. The pH (p<0.0001) and total volatile fatty acids (VFA, p<0.05) were enhanced by these precursors as sodium salt at 3, 6 and 9 h incubations, and pH (p<0.001) and total VFA (p<0.01) from fumarate or malate in acid form were enhanced at a late stage of fermentation (9 h and 12 h) as the addition level increased. pH was higher (p<0.001) for fumarate than for malate as sodium salt at 3 h and 6 h incubations. Propionate ($C_3$) proportion was increased (p<0.0001) but those of $C_2$ (p<0.05) and $C_4$ (p<0.01 - p<0.001) were reduced by the addition of sodium salt precursors from 3 h to 12 incubation times while both precursors in acid form enhanced (p<0.011 - p<0.0001) proportion of $C_3$ from 6h but reduced (p<0.018 - p<0.0005) $C_4$ proportion at incubation times of 1, 3, 9 and 12 h. Proportion of $C_3$ was increased (p<0.05 - p<0.0001) at all incubation times by both precursors as sodium salt while that of $C_3$ was increased (p<0.001) from 6h but $C_4$ proportion was decreased by both precursors in acid form as the addition level increased. Proportion of $C_3$ was higher (p<0.01 - p<0.001) for fumarate than malate as sodium salt from 6 h incubation but was higher for malate than fumarate in acid form at 9 h (p<0.05) and 12 h (p<0.01) incubation times. Increased levels (16 and 24 mM) of fumarate or malate as sodium salt (p<0.017) and both precursors in acid form (p<0.028) increased the total gas production, but no differences were found between precursors in both chemical types. Propionate precursors in both chemical types clearly reduced (p<0.0001 - p<0.0002) $CH_4$ production, and the reduction (p<0.001 - p<0.0001) was dose dependent as the addition level of precursors increased. The $CH_4$ generated was smaller (p<0.01 - p<0.0001) for fumarate than for malate in both chemical types. Addition of fumarate or malate as sodium type reduced (p<0.004) dry matter degradation while both precursors in both chemical types slightly increased neutral detergent fiber degradability of feed in the nylon bag.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.3
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• pp.91-98
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• 2017

The purpose of this study is to provide a design and operation technical guideline for meeting the appropriate design criteria to bio-gasification facilities treating organic wastes. 9 anaerobic digestion facilities which is normally operated during the field survey and 14 livestock manure farms were selected for precision investigation. the physicochemical analysis was performed on the moisture and organic contents, nutrients composition (carbohydrate, fat, protein), volatile fatty acids (VFAs), and nitrogen, etc. Volatile solids (VS) of organic wastes brought into the bio-gasification facilities were 2.81 % (animal manure only) and 5.92 % (animal manure+food waste), respectively. Total solids (TS) reults of samples from livestock farms were 5.6 % in piglets and 11~13 % in other kinds of breeding pigs. The actual methane yield based on nutrients contents was estimated to $0.36Sm^3CH_4/kgVS$ which is equivalent to 72 % of theoretical methane yield value. The optimum mixing ratio depending on the effect of the combined bio-gasification was obtained through the continuous stirred-tank reactor (CSTR) which is operated at different mixing ratio of swine manure and food waste leachate. The range of swine manure and food waste leachate from 60:40 to 40:60 were adequate to the appropriate conditions of anaerobic digestion; less than 100 gTS/, more than alkalinity of 1 gCaCO3/L, C/N ratio 12.0~30.0, etc.

• Journal of the Korean earth science society
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• v.23 no.3
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• pp.280-293
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• 2002

In this study, we analyzed the long-term distribution patterns of $CH_4$ determined from the Moo-Ahn (MAN) observatory in relation with those derived from the world major background monitoring sites. Comparison of the data were made using those data sets collected for the period between Aug. 1995 to Dec. 1991. The mean $CH_4$ concentration of MAN observatory was measured to be 1898${\pm}$85.3 ppb, recording the highest concentration of all the monitoring sites. When the concentration of $CH_4$ for different stations was compared over latitudinal scale, its concentration appeared to increase systematically as a function of latitude with an exception of MAN (and the other Korean monitoring site at Tae Ahn). Moreover, such phenomenon was more distinctive in Northern than Southern Hemisphere. According to the analysis of the monthly distribution patterns of $CH_4$ at MAN observatory, its concentration level began to increase from the months of February/March and peaked during August. In addition, when the level of oscillation in monthly concentrations (between the maximum and minimum values) was checked, differences were significant between MAN and other monitoring stations. If the rate of concentration change was checked using the data sets collected for this limited time period in terms of linear regression analysis, results for MAN showed the highest annual increasing rate of 16.5 ppb. It is hence suggested that the largest variability in the $CH_4$ distribution patterns at MAN observatory may be reflected by the high irregularity in its source/sink processes.