• Korean Journal of Microbiology
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• v.47 no.1
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• pp.66-73
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• 2011

Bacterial density distributions of gut microbes in the digestive organs of Harmonia axyridis collected from three different sources (JK, CK, and CJ) were $6.0{\times}10^4$ CFU/gut under aerobic culture condition and $8.0{\times}10^6$ CFU/gut under anaerobic culture condition. Seven colony types were observed under aerobic condition and three types of similarity were detected under anaerobic condition. In total, 116 strains, including 34 strains under aerobic condition, were isolated from the digestive organs of H. axyridis. Based on the analysis of the 16S rRNA gene sequence, aerobic gut microbes were assigned to the Proteobacteria, Actinobacteria, Firmicutes, and Deinococcus-Thermus. A large number of isolates belonged to the genus Bacillus and Staphylococcus of the Firmicutes commonly found in H. axyridis from different sites. Anaerobic gut microbes were found to be similar according to colony morphological, phylogenetic analysis using ARDRA. Eighty-two anaerobic gut microbes were clustered into 17 different ARDRA types according to HaeIII. Representative anaerobic gut microbes in each ARDRA group were divided into five species of ${\gamma}$-Proteobacteria based on 16S rRNA gene sequence analysis; Hafnia alvei, Enterobacter ludwigii, Enterobacter kobei, Pseudomonas oryzihabitans and Pseudomonas koreensis. Phylogenetic analysis indicated that about 70% of the isolates belonged to ${\gamma}$-Proteobacteria, suggesting predominance of gut microbes.

• Proceedings of the Membrane Society of Korea Conference
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• 1993.04a
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• pp.41-41
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• 1993

Recently, the advanced membrane separation technology has even been applied to the post treatment to biological process of wastewater treatment, since the efficiency of biological treatment significantly depends on maintaining a high biomass concentration in the bioreator. Particularly, anaerobic microbes in the biological system have slower growth rates than aerobic microbes and thus it takes a long hydaulic retention time(HRT) to prevent biomass washout in the completely mixed anaerobic digester. The anaerobic sludge also has poor settleability owing to its diffusible and somewhat filamentous nature. Moreover, the residual gasification and consequent sludge rise in the clarifier compartment become a considerable problem, which proves that complete separation of biological solids is difficult.

• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1808-1819
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• 2017

Knowledge on the functional characteristics and temporal variation of anaerobic bacterial populations is important for better understanding of the microbial process of two-stage anaerobic reactors. However, owing to the high diversity of anaerobic bacteria, close attention should be prioritized to the frequently abundant bacteria that were defined as core bacteria and putatively functionally important. In this study, using MiSeq sequencing technology, the core bacterial community of 98 operational taxonomic units (OTUs) was determined in a two-stage upflow blanket filter reactor treating pharmaceutical wastewater. The core bacterial community accounted for 61.66% of the total sequences and accurately predicted the sample location in the principal coordinates analysis scatter plot as the total bacterial OTUs did. The core bacterial community in the first-stage (FS) and second-stage (SS) reactors were generally distinct, in that the FS core bacterial community was indicated to be more related to a higher-level fermentation process, and the SS core bacterial community contained more microbes in syntrophic cooperation with methanogens. Moreover, the different responses of the FS and SS core bacterial communities to the temperature shock and influent disturbance caused by solid contamination were fully investigated. Co-occurring analysis at the Order level implied that Bacteroidales, Selenomonadales, Anaerolineales, Syneristales, and Thermotogales might play key roles in anaerobic digestion due to their high abundance and tight correlation with other microbes. These findings advance our knowledge about the core bacterial community and its temporal variability for future comparative research and improvement of the two-stage anaerobic system operation.

• KCID journal
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• v.16 no.1
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• pp.92-93
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• 2009

• Journal of Soil and Groundwater Environment
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• v.15 no.6
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• pp.114-121
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• 2010

Oxygen sensitivity and substrate requirement have been known as possible reasons for the intricate growth of Dehalococcoides spp. and limiting factors of for routinely applying bioaugmentation using anaerobic Dehalococcoides-containing microbes for remediating chlorinated organic compounds. To explore the effect of the short-term exposure of the short-term exposure of oxygen on Dehalococcoides capability, dechlorination performance, and hydrogen production fermentation from formate, an anaerobic reductive dechlorination mixed-culture (Evanite culture) including dehalococcoides spp. was in this study. In the results, once the mixed-culture were exposed to oxygen, trichloroethylene (TCE) degradation rate decreased and it was not fully recovered even addition of excess formate for 40 days. In contrast, hydrogen was continuously produced by hydrogen-fermentation process even under oxygen presence. The results indicate that although the oxygen-exposed cells cannot completely dechlorinate TCE to ethylene (ETH), hydrogen fermentation process was not affected by oxygen presence. These results suggest that dechlorinating microbes may more sensitive to oxygen than fermenting microbes, and monitoring dechlorinators activity may be critical to achieve an successful remediation of a TCE contaminated-aquifer through bioaugmentation using Dehalococcoides spp..

• Journal of Environmental Health Sciences
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• v.32 no.2 s.89
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• pp.192-197
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• 2006

This study was performed to investigate anti-microbial activity of soybean extract against oral microbes, and to determine the minimum inhibition concentration (MIC) for microbes causing oral diseases. The soybean extract was prepared using ethyl acetate and it was treated with 16 types of oral microbes at a concentration of 5.00 mg/ml (0.5%). The MIC of soybean extract for three major microbes causing oral diseases was determined. The anti-microbial activity and MIC were measured using broth dilution method. Significant reduction of microbial activities of 9 types oral microbes when the soybean extract was added to the broth compared to the control (p<0.01). The extract showed higher anti-microbial activity against some anaerobic strains (P. gingivalis and P. intermieia). S. mutans, which causes dental caries, showed MIC at a concentration of 40 mg/ml for the soybean extract. P. gingivalis, which causes adult periodontal disease, showed MIC at a concentration of 20 mg/ml for the extract. C. albicans, which causes denture stomatitis and angular stomatitis, showed MIC at a concentration of 20 mg/ml for the extract. These results indicate that soybean extract showed anti-microbial effort against 9 types of oral microbes, and the anti-microbial effect of the extract against oral microbes was stronger against fungi than against bacteria. The anti-microbial mechanism of soybean extract against oral microbes should be investigated, and more research for clinical application is required at a level of actual intake.

• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.366-372
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• 2003

The production of microbiologically enriched cultures that degrade cis- 1,2-dichloroethylene(DCE) under anaerobic conditions was investigated. Among 80 environmental samples, 19 displayed significant degradation of $10{\mu}M$ cis-DCE during 1 month of anaerobic incubation, and one sediment sample collected at a landfill area (Nanji-do, Seoul, Korea) showed the greatest degradation ($94\%$). When this sediment culture was subcultured repeatedly, the ability to degrade cis-DCE gradually decreased. However, under Fe(III)-reducing conditions, cis-DCE degradation by the subculture was found to be maintained effectively. In the Fe(III)-reducing subculture, vinyl chloride (VC) was also degraded at the same extent as cis-DCE No accumulation of VC during the cis-DCE degradation was observed. Thus, Fe(III)-reducing microbes might be involved in the anaerobic degradation of the chlorinated ethenes. However, the subcultures established with Fe(III) could function even in the absence of Fe(III), showing that the degradation of cis-DCE and VC was not directly coupled with the Fe(III) reduction. Consequently, the two series of enrichment cultures could not be obtained that degrade both cis-DCE and VC in the presence or absence of Fe(III). Considering the lack of VC accumulation, both cultures reported herein may involve interesting mechanism(s) for the microbial remediation of environments contaminated with chlorinated ethenes. A number of fermentative reducers (microbes) which are known to reduce Fe(III) during their anaerobic growth are potential candidates involved in cir-DCE degradation in the presence and absence of Fe(III).

• Journal of Korean Society of Water and Wastewater
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• v.24 no.5
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• pp.561-572
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• 2010

The efficiency of biological hydrolysis at $80^{\circ}C$ on municipal solid waste mixed with anaerobic digestion sludge was investigated in 100L batch reactors. The hydrolysis effect was observed within a day, when the hydrolysis reactor used for a pre-treatment reactor for methanogenesis, and the effect was observed during two days, When the reactor used for post-treatment reactor. For both configurations, methane production rate decreased, when hydrolysis was carried out more than a day. Gaseous ammonia in the hydrolysis reactors was successtully removed by the ammonia stripping system. Microbial diversity analysis on the hydrolysis reactors indicated dependency of microbial diversity on the configuration of the hydrolysis reactors. Carbohydrate and lactate degrading microbes dominated in the hydrolysis reactor, when the hydrolysis reactor used for a pre-treatment reactor for methanogenesis, while protein degrading microbes dominated in the post-treatment reactor.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.11
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• pp.1577-1586
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• 2011

This study was carried out to estimate effects of synbiotics containing anaerobic microorganisms and prebiotics on in vitro fermentation characteristics and in situ disappearance rate of fermented total mixed ration (F-TMR). For the in vitro trial, ninety vinyl bags were prepared to analyze temperature, pH, ammonia concentration, microbial growth rate and short chain fatty acid concentration. For the in situ trial, one hundred twenty nylon bags were prepared to analyze dry matter (DM), acid detergent fiber (ADF) and neutral detergent fiber (NDF) disappearance rate. Treatments consisted of a basal diet (US) with prebiotics and probiotics from anaerobic mold (MS), bacteria (BS), yeast (YS) or compound (CS). It was found that temperatures at 14 and 21 days were significantly higher (p<0.05) in the YS and CS than in the others. The pH at 21 days was lower in the CS than in the US. The synbiotic treatments had significantly increased (p<0.05) ammonia concentration at 21 days. The DM disappearance at 72 h was significantly higher (p<0.05) in the MS and CS than in the others. ADF and NDF disappearance rate tended to increase at a rate similar to the DM disappearance rate. Therefore, this study suggests that synbiotics (probiotics with prebiotics) may partially help the quality of fermentation and digestibility of TMR (MS and CS) as fiber disappearance.

• Journal of Animal Environmental Science
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• v.4 no.2
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• pp.175-182
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• 1998

For the recycling of swine takes 2 different steps in fermenting procedure, acidogenic reactor and methanogenic reactor, the activity of involved microbes can be maintained at the maximum level. This study showed applying 2 separate steps in anaerobic fermentation has improved fermenting efficiency over the conventional 1 step fermentation. Accordingly, the results are coincident with the hypothesis in which 2 steps acidogenic and methanogenic reactor fermentation is more efficient than conventional (1 step) fermentation that makes poisonous materials be obviate and abate. And the results also get the effective performance in the production of methane gas.