• Journal of Environmental Science International
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• v.9 no.1
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• pp.75-80
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• 2000

Kinetic data for the acid phase anaerobic digestion were presented in this study and the constants were determined with acid production rate and gas production rate. Process models based on continuous culture theory were used to describe the characteristics of the acid forming microorganisms and to enable further development toward utilization of the process in a more rational manner. Acid phase digestion can be separated with appropriate manipulation of hydraulic retention time in anaerobic digestion. Kinetic analysis of data from the various hydraulic retention times using a phase specific model obtained form the acid phase indicated maximum specific growth rate of 0.40/h, saturation constant of 2,000mgCOD.$\ell$, yield coefficient of 0.35 mgVSS/msCOD utilized and decay constant of 0.04/h for the acid production rate. Similar analysis of data for the gas production rate indicated maximum specific growth rate of 0.003/h, saturation constant of 2,200mgCOD/$\ell$, yield coefficient of 0.035 mgVSS/mgCOD utilized and decay constant of 0.06/h.

• 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 Animal Science and Technology
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• v.45 no.6
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• pp.1019-1030
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• 2003

The study was conducted to isolate and identify highly fibrolytic anaerobic fungi from the guts of a Hanwoo steer and a Korean native goat, and then investigate the characterization of cellulolytic activity of an anaerobic fungus. Twenty-one anaerobic fungal colonies were isolated in the study, in which 16 colonies were isolated from the rumen contents of the Hanwoo steer and 5 colonies from the duodenal fluids of the Korean native goat. Four anaerobic fungi were selected based on higher cellulolytic enzyme activities to identify under a optical microscope. NLRI-M003 and -T004 belong to Neocallimastix genus and NLRI-M014 belongs to Piromyces genus based on the morphology of their thallus, sporangia, rhizoid and the number of flagella. NLRI-M001 appeared to be an unknown strain of anaerobic fungi due to its different morphology from existing types of anaerobic fungi, though the morpholgoy is similar to Orpinomyces sp. Supplementation of 2% anaerobic fungal culture(NLRI-M003) in rumen-mixed microorganisms increased in vitro DM degradability of rice straw and filter paper up to 4 and 11%, respectively, compared with non-supplementation(control). CMCase and xylanase activities in in vitro culture were also higher in 2% fungal supplementation than controls in both rice straw and filter paper substrates.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.4
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• pp.393-401
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• 2016

Anaerobic digestion is a collection of naturally occurring processes that convert organic matter and liquid residue, so-called digestate. The use of digestate biofertilizers is one of the important components of integrated nutrient management, as they are renewable sources of plant nutrients for sustainable agriculture. Seeds of Italian ryegrass (Lolium multiflorum L.) were germinated in different concentration of Chlorella in order to investigate it's the effect of Chlorella on growth parameters, seed germination and early growth. The experiment using plug tray was conducted at the green house placed in the Sangji University. The experiment consisted of nine treatments including different concentrations of Chlorella sp. culture solution and non-treated control. The germination percentage at the treatment with 25% Chlorella sp. culture solution was greater than that of control. The 50% concentration of Chlorella sp. culture solution was found to promote a better seedling growth in terms of shoot length, fresh weight and dry weight compared to the anaerobic digestate. Results showed that the best concentration of Chlorella culture solution was achieved by the 50% concentration of Chlorella culture solution treatment. As a conclusion, the application of Chlorella culture solution was found to be able to promote the germination and shoots growth of Italian ryegrass.

• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.235-242
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• 2000

The purpose of this in vitro study was to evaluate the sealing ability of three sealers(Sealapex, Pulp canal sealer, AH26) used with continuous wave method using an anaerobic bacterial leakage model. 53 extracted human teeth with straight and single canals were prepared with crown-down pressureless technique using .04, .06 taper Profile(Maillefer, Swiss). Master apical file was maintained as #35 K-file. All canals of the experimental teeth were obturated with continuous wave method using System B(Analytic technology, U.S.A.) The teeth were randomly divided into three experimental groups of 15 and two control groups of 4. Experimental group 1 was obturated with Sealapex and group 2 with Pulp canal sealer, and group 3 with AH26. A dual chamber anaerobic bacterial leakage model was assembled. Brain heart infusion with yeast extract, hemin, menadion, and the chromogenic indicator bromocresol purple was used as the culture broth for Fusobacterium nucleatum(VPI 10197), The specimens were incubated in anaerobic chamber at $37^{\circ}C$ and were observed every 2 to 3 clays, The coronal leakage was evaluated through the color change of culture broth in lower chamber for 60 days. The results were as follows: 1. The incidence of bacterial leakage in group 1 (Sealapex group was 80%, 53% in group 2 (Pulp canal sealer), 27% in group 3 (AH26). 2. There were statistically significant differences in leakage scores between group 1 and group 2, and between group 1 and group 3, respectively. (P<0.05) 3. There was no significantly difference in leakage score between group 2 and group 3. (P>0 05)

• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.639-644
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• 2019

Diarrhea is one of the most common infectious diseases known worldwide. However, few studies have examined anaerobic diarrhea-causing bacteria (DB), which are difficult to culture. Recent advances in molecular biology have facilitated the detection and analysis of anaerobic DB. In this study, long-term trends in anaerobic DB were evaluated in Korea. From 2010 to 2018, symptoms of diarrhea reported were analyzed among patients hospitalized at the Dankook University Hospital in Korea. Results of multiplex polymerase chain reaction based on seasonality, age, overlapping infection, and other factors in patients were evaluated. DB were detected in 38.2% of 1716 stool specimens in the duration of the study. Of the pathogens detected using this method, 49.8% (n = 405/813) were anaerobic bacteria, including Clostridioides perfringens, Campylobacter spp., Clostridioides difficile toxin B, and Aeromonas spp. Among the four anaerobic bacteria, Clostridioides perfringens was the most commonly occurring (15.5%; n = 126/813). Detection rates of Clostridioides perfringens, Clostridioides difficile toxin B, and Aeromonas spp. were 34.1% (n = 22/55), 34.9% (n = 43/126), and 40.0% (n = 38/109), respectively. The detection rate of Campylobacter spp. (32.7%; n = 37/115) was the highest in patients between 10 and 20 years of age. The detection rate of anaerobic DB showed an increase in 2018 as compared with that in 2010, and the number of events of diarrhea caused by anaerobic DB also increased in this duration. Further studies are required to devise methods that might prevent the proliferation of anaerobic DB.

• Transactions of the Korean hydrogen and new energy society
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• v.16 no.4
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• pp.315-323
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• 2005

The integrated or the two-stage (dark anaerobic and photosynthetic) fermentation processes were compared for the hydrogen production using purple non-sulfur photosynthetic bacteria, Rhodopseudomonas palustris P4. Cell growth, pH changes and organic acids and bacteriochlorophyll contents were monitored during the processes. Culture broth of Rps. palustris P4 exhibited dark-red during the photosynthetic culture condition, while yellow under the anaerobic condition without light. Rps. palustris P4 grown at the photosynthetic condition evolved 0.38 and 1.33 ml $H_2$/mg-dcw during the dark and the light fermentation, respectively, which were totally 1.71 ml $H_2$/mg-dcw at the two-stage fermentation. The rate of hydrogen production using Rps. palustris P4 grown under the dark anaerobic condition was 2.76 ml $H_2$/mg-dcw which consisted of 0.46 and 2.30 ml $H_2$/mg-dcw from the dark and the photosynthetic fermentation processes, respectively. Rps. palustris P4 grown under dark anaerobic conditions produced $H_2$ 1.6 times higher than that of grown under the photosynthetic condition. However, total fermentation period of the former was 1.5 times slower than that of the latter, because the induced time of hydrogen production during the photosynthetic fermentation was 96 and 24 hours when the seed culture was the dark anaerobic and photosynthetic, respectively. The integrated fermentation process by Rps. palustris P4 produced 0.52 ml $H_2$/mg-dcw(1.01 mol $H_2$/mol glucose), which was 20% of the two-stage fermentation.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.89-91
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• 2000

Polynuclear aromatic hydrocarbon (PAH) compounds are highly carcinogenic chemicals and common groundwater contaminants that are observed to persist in soils. The adherence and slow release of PAHs in soil is an obstacle to remediation and complicates the assessment of cleanup standards and risks. Biological degradation of PAHs in soil has been an area of active research because biological treatment may be less costly than conventional pumping technologies or excavation and thermal treatment. Biological degradation also offers the advantage to transform PAHs into non-toxic products such as biomass and carbon dioxide. Ample evidence exists for aerobic biodegradation of PAHs and many bacteria capable of degrading PAHs have been isolated and characterized. However, the microbial degradation of PAHs in sediments is impaired due to the anaerobic conditions that result from the typically high oxygen demand of the organic material present in the soil, the low solubility of oxygen in water, and the slow mass transfer of oxygen from overlying water to the soil environment. For these reasons, anaerobic microbial degradation technologies could help alleviate sediment PAH contamination and offer significant advantages for cost-efficient in-situ treatment. But very little is known about the potential for anaerobic degradation of PAHs in field soils. The objectives of this research were to assess: (1) the potential for biodegradation of PAH in field aged soils under denitrification conditions, (2) to assess the potential for biodegradation of naphthalene in soil microcosms under denitrifying conditions, and (3) to assess for the existence of microorganisms in field sediments capable of degrading naphthalene via denitrification. Two kinds of soils were used in this research: Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS). Results presented in this seminar indicate possible degradation of PAHs in soil under denitrifying conditions. During the two months of anaerobic degradation, total PAH removal was modest probably due to both the low availability of the PAHs and competition with other more easily degradable sources of carbon in the sediments. For both Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS), PAH reduction was confined to 3- and 4-ring PAHs. Comparing PAH reductions during two months of aerobic and anaerobic biotreatment of MHS, it was found that extent of PAHreduction for anaerobic treatment was compatible with that for aerobic treatment. Interestingly, removal of PAHs from sediment particle classes (by size and density) followed similar trends for aerobic and anaerobic treatment of MHS. The majority of the PAHs removed during biotreatment came from the clay/silt fraction. In an earlier study it was shown that PAHs associated with the clay/silt fraction in MHS were more available than PAHs associated with coal-derived fraction. Therefore, although total PAH reductions were small, the removal of PAHs from the more easily available sediment fraction (clay/silt) may result in a significant environmental benefit owing to a reduction in total PAH bioavailability. By using naphthalene as a model PAH compound, biodegradation of naphthalene under denitrifying condition was assessed in microcosms containing MHS. Naphthalene spiked into MHS was degraded below detection limit within 20 days with the accompanying reduction of nitrate. With repeated addition of naphthalene and nitrate, naphthalene degradation under nitrate reducing conditions was stable over one month. Nitrite, one of the intermediates of denitrification was detected during the incubation. Also the denitrification activity of the enrichment culture from MHS slurries was verified by monitoring the production of nitrogen gas in solid fluorescence denitrification medium. Microorganisms capable of degrading naphthalene via denitrification were isolated from this enrichment culture.

• Microbiology and Biotechnology Letters
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• v.13 no.2
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• pp.169-172
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• 1985

The assimilability of glucose and xylose of Rhodopseudomonas K-7, whose hydrogen evolution has been characterized previously, was investigated under the anaerobic photosynthetic and the aerobic dark conditions. This organism is able to grow well in the medium containing glutamate and malate as organic substances under the anaerobic light condition. However, the substitution of glucose for malate retarded the growth rate, while the addition of glucose to the seed culture remarkably promoted the utilization of glucose added in the main culture. Optimal glucose concentration in the seed culture to induce glucose assimilability of the organism was around the concentration of 60 mM of glucose. Then, the seed culture grown in the medium containing 60 mM of glucose were inoculated in the medium containing 10, 20, 30, 60 and 100 mM of glucose respectively. The results were revealed that the consumable content of glucose was limited even though the high concentrations of glucose was contained in the medium. The consumption of considerable amount of glucose was observed when cultured under the aerobic dark conditions than the anaerobic illuminated conditions.

• Journal of Microbiology and Biotechnology
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• v.21 no.9
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• pp.885-892
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• 2011

The bacterial communities in the intestinal tracts of earthworm were investigated by culture-dependent and -independent approaches. In total, 72 and 55 pure cultures were isolated from the intestinal tracts of earthworms under aerobic and anaerobic conditions, respectively. Aerobic bacteria were classified as Aeromonas (40%), Bacillus (37%), Photobacterium (10%), Pseudomonas (7%), and Shewanella (6%). Anaerobic bacteria were classified as Aeromonas (52%), Bacillus (27%), Shewanella (12%), Paenibacillus (5%), Clostridium (2%), and Cellulosimicrobium (2%). The dominant microorganisms were Aeromonas and Bacillus species under both aerobic and anaerobic conditions. In all, 39 DNA fragments were identified by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis. Aeromonas sp. was the dominant microorganism in feeds, intestinal tracts, and casts of earthworms. The DGGE band intensity of Aeromonas from feeds, intestinal tracts, and casts of earthworms was 12.8%, 14.7%, and 15.1%, respectively. The other strains identified were Bacillus, Clostridium, Enterobacter, Photobacterium, Pseudomonas, Shewanella, Streptomyces, uncultured Chloroflexi bacterium, and uncultured bacterium. These results suggest that PCR-DGGE analysis was more efficient than the culturedependent approach for the investigation of bacterial diversity and the identification of unculturable microorganisms.