• Korean Journal of Microbiology
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• v.40 no.2
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• pp.94-99
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• 2004

The activities of enzymes that act on oxygen derivatives in Rhodobacter sphaeroides D-230 were investigated under various culture conditions. Intracellular SOD activity from the cells grown in aerobic or anaerobic culture conditions was highest at pH 7.0 and pH 8.0, respectively. On the other hand, extracellular SOD activity was highest at pH 6.0. Catalase activity was highest at neutral pH in both cases. Growth of R. sphaeroides D-230 in aerobic or anaerobic culture conditions was inhibited by methyl viologen. As R. sphaeroides D-230 was cul-tured aerobically, SOD activity was increased about 2-fold by addition of iron ion. But $Mn^+2$ had little effect on the SOD activity of R. sphaeroides D-230 grown in aerobically. NaCN, the inhibitor of Cu$.$Zn-SOD, did not inhibit SOD activity. But, $NaN_3$, the inhibitor of Mn-SOD, inhibited SOD activity in anaerobic cultures con-dition. Therefore, R. sphaeroides D-230 produce Mn-SOD in anaerobic condition, although Fe-Sod is produced in aerobic condition. The activity of catalase was induced by methyl viologen, however, extremely inhibited by NaCN and $NaN_3$.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.4
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• pp.171-176
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• 1975

The rate and extent of decomposition of rice straw and compost in an acid sulfate soil amended with urea and lime and incubated under aerobic and anaerobic(flooded) conditions were investigated in the laboratory. Results are summarized as follows: 1. The rate of compost(alone) decomposition in a flooded soil was more than twice as high as all other treatments, which included rice straw+urea, rice straw+lime, rice straw (alone), and compost+lime. Lime appeared to suppress the decomposition of compost in a flooded soil but actually enhanced its decomposition under aerobic conditions. 2. Compost decomposition in both anaerobic and aerobic environments was characterized by single maximum peak rates of $CO_2$ evolution that were reached soon after the start of incubation. 3. Both urea and lime greatly increased the rate and extent of rice straw decomposition in the soil when incubated aerobically, although urea had a greater effect than did liming. Decomposition rates were characterized by the appearance of two maximum peak rates, a greater primary peak and a smaller secondary peak. 4. The percent decomposition of rice straw in soil incubated aerobically was approximately half (10.8%) that of compost(23.1%). However, percent decomposition of these substrates in soil amended with lime was essentially the same; i.e., rice straw+lime (29.4%) and compost+lime(31.6%). 5. There is a need to investigate the possible interaction between the addition of lime (pH) and supplemental nitrogen applied to acid sulfate soils and how this interaction might affect the decomposition of organic wastes and residues.

• Journal of Animal Environmental Science
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• v.11 no.2
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• pp.97-102
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• 2005

Anaerobic decomposition is one of the most common processes in nature and has been extensively used in waste and wastewater treatment for several centuries. New applications and system modifications continue to be adapted making the process either more effective, less expensive, or suited to the particular waste in question and the operation to which it is to be applied. Animal manure is a highly biodegradable organic material and will naturally undergo anaerobic fermentation, resulting in release of noxious odors, such as in manure storage pits. Depending on the presence or absence of oxygen in the manure, biological treatment process may be either aerobic or anaerobic. Under anaerobic conditions, bacteria carry on fermentative metabolisms to break down the complex organic substances into simpler organic acids and then convert them to ultimately formed methane and carbon dioxide. Anaerobic biological systems for animal manure treatment include anaerobic lagoons and anaerobic digesters. Methane and carbon dioxide are the principal end products of controlled anaerobic digestion. These two gases are collectively called biogas. The biogas contains $60\~70\%$ methane and can be used directly as a fuel for heating or electrical power generation. Trace amounts of ammonia and hydrogen sulfide ($100\~300\;ppm$) are always present in the biogas stream. Anaerobic lagoons have found widespread application in the treatment of animal manure because of their low initial costs, ease of operation and convenience of loading by gravity flow from the animal buildings. The main disadvantage is the release of odors from the open surfaces of the lagoons, especially during the spring warm-up or if the lagoons are overloaded. However, if the lagoons are covered and gases are collected, the odor problems can be solved and the methane collected can be used as a fuel. Anaerobic digesters are air-tight, enclosed vessels and are used to digest manure in a well-controlled environment, thus resulting in higher digestion rates and smaller space requirements than anaerobic lagoons. Anaerobic digesters are usually heated and mixed to maximize treatment efficiency and biogas production. The objective of this work was to review a current anaerobic biological treatment of animal manure for effective new technologies in the future.

• Journal of Crop Science and Biotechnology
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• v.10 no.2
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• pp.64-72
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• 2007

Iron is an important micronutrient for plants. Iron metabolism is a complex mechanism under a delicate balance. Iron metabolism represents two major problems for plants: deficiency as a consequence of solubility problems and toxicity due to excess solubility in anaerobic conditions. In the last few years, new genes have been discovered that influence iron uptake, transport and storage. Irrigated rice is exposed to high levels of $Fe^{II}$, normally rare in aerobic soil conditions. The implications of altering iron uptake rates and the effects of newly discovered genes are discussed.

• Journal of Microbiology and Biotechnology
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• v.28 no.6
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• pp.917-930
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• 2018

Intracellular synthesis of silver/silver chloride nanoparticles (Ag/AgCl-NPs) using Meyerozyma guilliermondii KX008616 is reported under aerobic and anaerobic conditions for the first time. The biogenic synthesis of Ag-NP types has been proposed as an easy and cost-effective alternative for various biomedical applications. The interaction of nanoparticles with ethanol production was mentioned. The purified biogenic Ag/AgCl-nanoparticles were characterized by different spectroscopic and microscopic approaches. The purified nanoparticles exhibited a surface plasmon resonance band at 419 and 415 nm, confirming the formation of Ag/AgCl-NPs under aerobic and anaerobic conditions, respectively. The planes of the cubic crystalline phase of the Ag/AgCl-NPs were confirmed by X-ray diffraction. Fourier-transform infrared spectra showed the interactions between the yeast cell constituents and silver ions to form the biogenic Ag/AgCl-NPs. The intracellular Ag/AgCl-NPs synthesized under aerobic condition were homogenous and spherical in shape, with an approximate particle size of 2.5-30nm as denoted by the transmission electron microscopy (TEM). The reaction mixture was optimized by varying reaction parameters, including temperature and pH. Analysis of ultrathin sections of yeast cells by TEM indicated that the biogenic nanoparticles were formed as clusters, known as nanoaggregates, in the cytoplasm or in the inner and outer regions of the cell wall. The study recommends using the biomass of yeast that is used in industrial or fermentation purposes to produce Ag/AgCl-NPs as associated by-products to maximize benefit and to reduce the production cost.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.762-766
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• 2001

The nar promoter of Escherichia coli was known to induce maximally under anaerobic or microaerobic conditions in the presence of nitrate. In this study, the nar promoter was tested to see whether the expression level of a reporter gene which fused lacZ gene at nar promoter's downstream, in the some gram negative host strains(Agrobacterium, Pseudomonas and Rhizobium). A nar promoter system(Combination of nar promoter and gram negative strain) was grown under aerobic conditions to absorbance at 600 nm of nearly 2.0 and then, the nar promoter was induced by lowering DO to 1-2% with alternating microaerobic and aerobic condition in the fermentor cultures, using different gram negative hosts. For a wild type nar promoter (pNW61), it was possible to maintain production of ${\beta}-galactosidase$ activity per cell(specific ${\beta}-galactosidase$ activity) at 14,000, 9600, 45 Miller units in the presence of 1% nitrate. and for a nitrate - independent nar promoter (pNW618) at 12,000, 10,400 and 58 Miller units in the absence of nitrate ion, respectively.

• Journal of Applied Biological Chemistry
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• v.54 no.3
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• pp.225-229
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• 2011

This research was carried out to elucidate the impacts of dissolved oxygen (DO) concentration to phosphorus release mechanism from soil into water in lakes. $PO_4-P$ contributed to the growth of the total phosphorus (T-P). $PO_4-P$ was steadily increasing because water was accumulating $PO_4-P$. T-P was closely related to turbidity, pH, and DO. We found that DO had decreased because DO was consumed in organic matter decomposition, and that the resulting anaerobic decomposition occurred whenever water had run out of DO. We also found that pH had decreased sharply by production of organic acid by the anaerobic decomposition and that T-P decreased because a decrease in pH removed turbidity by precipitation. T-P was dissolved without microbial decomposition. This mechanism was of great importance in lakes because phosphorus is released from soil into water.

• Korean Journal of Environmental Agriculture
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• v.22 no.1
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• pp.26-35
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• 2003

An investigation was carried out to evaluate the effects of pebble size on the small-scale sewage treatment apparatus by natural purification method that consisted of aerobic and anaerobic plot. pH and EC in both plots varied minimally regardless of pebble size. DO in aerobic plot increased as the pebble size decreased. That in the anaerobic plot was slightly less in comparison with that of the aerobic plot but varied minimally, $2.4{\sim}5.1\;mg/L$ regardless of pebble size. Under all experimental conditions, removals of BOD, COD and turbidity in anaerobic plot were more than 98, 91 and 98, 98% respectively. Removals of T-N and T-P increased as pebble size decreased. Under all experimental conditions, removals of T-N and T-P in anaerobic plot were about $45{\sim}59$ and $480{\sim}96%$, respectively. Judging from the above results, it should be considered that the optimum pebble size and pebble permeability in both plot was $2{\sim}4$ and $0.1{\sim}4\;mm$, respectively.

• Journal of Korean Society of Disaster and Security
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• v.12 no.1
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• pp.23-34
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• 2019

It is an urgent issue to manage and reduce non-point pollution sources for improving the water quality of stream and lakes in rural areas. In this study, in order to reduce non-point pollution sources in rural area, Gabion mattresses was proposed to provide protection of riverbanks with anaerobic and aerobic area. The utilization of this was assessed by lab scale model test and pilot plant test. After filling the inside of the gabion mattresses with aggregate, the filtration zone under anaerobic and aerobic conditions was formed to treat the contaminants. In addition, vegetation was deposited on the surfae of the gabion to prevent the inflow of soil and to promote purification by the plant. COD and nitrogen content (T-N, $NH_4{^+}$, -N, $NO_3{^-}N$) were monitored in model and field tests. The lab scale model test showed removal efficiency of 17% of TCOD, 35% of SCOD, 14% of TN, 62% of $NH_4{^+}$, -N, and 33% of $NO_3{^-}$ N. Also, pilot plant test showed removal efficiency of 24% of TCOD, 29% of SCOD, 47% of TN, 50% of $NH_4{^+}-N$, 33% of $NO_3{^-}$, N and 29% of TP.

• Journal of Korean Society on Water Environment
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• v.21 no.5
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• pp.490-495
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• 2005

Since there are very limited numbers of thermophilic anaerobic digesters being operated, it is often difficult to start up a new one using sludge from an existing reactor as a seed. However, for obvious reasons it seems few attempts have been made to compare the start-up performance of thermophilic anaerobic digestion using different sources of seed sludges. The purpose of this study was to evaluate the start-up performance of anaerobic digestion using aerobic Waste Activated Sludge (WAS) from a plant and mesophilic Anaerobic Digested Sludge (ADS) as the seed source at both mesophilic ($35^{\circ}C$) and thermophilic ($55^{\circ}C$) temperatures. In this study, two experiments were conducted. First, thermophilic anaerobic reactors were seeded with WAS (VSS = 4,400 mg/L) and ADS (VSS = 14,500 mg/L) to investigate start-up performance with a feed of acetate as well as propionate. The results show that WAS started to produce $CH_4$ soon after acetate feeding without a lag time, while ADS had a lag time of 10 days. When the feed was changed to propionate, WAS removed propionate down to below the detection limit of 10 mg/L, while ADS removed little propionate and produced little $CH_4$. Second, in order to further compare the methanogenic activity of WAS and ADS, both mesophilic and thermophilic reactors were operated. WAS acclimated to anaerobic conditions shortly and after acclimating it produced more $CH_4$ than ADS. WAS at mesophilic temperature biodegraded acetate at the same rate as for thermophilic. However WAS at mesophilic temperature biodegraded propionate at a much faster rate than at thermophilic. WAS as the seed source of anaerobic digestion resulted in much better performance than ADS at both mesophilic and thermophilic temperatures for both acetate and propionate metabolism.