• 한국환경보건학회지
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• 제23권1호
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• pp.43-49
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• 1997

This study was aimed to estimate removal efficiency(%) of BER(Biofilm-Electrode Reactor) and A.S(Activated Sludge) treatments. When were analyzed COD$_{Cr}$, NH$_3$-N and T-P by current density and reaction time, the results were as follows : 1) In BER treatment, the removal efficiency of COD$_{Cr}$ in domestic wastewater was 79-86% when current density was 2.39 mA/dm$2$(15mA)-3.98 mA/dm$^2$(25mA) and reaction time was 48 hr. 2) Removal efficiency of NH$_3$-N was 71-73% when current density was 2.39-3.98 mA/dm$^2$ and reaction time 48 hr. 3) When the reaction time was 48 hr removal efficiency(%) of BER treatment for COD$_{Cr}$, NH$_3$-N and T-P were more excellent than A.S. treatment. And then we prospect that was because activated microorganism colonies attached in biofilm on surface of electrode pannel. Therefore, In order to derive BER treatment efficiency(%) should establish optimum conditions of pH, temp., reaction time, current density and biochemical and electrochemical states.

• 한국축산시설환경학회지
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• 제20권2호
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• pp.77-84
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• 2014

This study was conducted to investigate the bacterial capability to accumulate phosphorus during liquid composting process of pig slurry. Storage liquid compost and pig slurry were analyzed by using MALDI-TOF technique, which showed the colonies of Acinetobacter towneri and Bacillus licheniformis. In addition, bacterial colonies were isolated under high phosphoric acid conditions using X-phosphate MOPS medium with the addition of 2 mM $K_2HPO_4$. Microbial growth was observed in high and low phosphoric conditions due to the growth of bacterial diversities in the liquid fertilizer and slurry. The colonies isolated in the high phosphoric acid medium were uncultured bacterium clone and Acinetobacter sp. were identified by analysis of 16S rRNA gene sequences. Uncultured bacterium showed higher growth rate and excellent phosphorus ability then Acinetobacter sp.. In addition to Paenibacillus sp. AEY-1 isolated from pig slurry performed excellent phosphorus utilizing capability.

• Journal of Biosystems Engineering
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• 제43권4호
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• pp.401-409
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• 2018

Decay of fruit is one of the greatest issues in fruit storage. Purpose: In this study, citrus sterilization was performed to evaluate a dry sterilization method using an atmospheric-pressure nonthermal plasma treatment based on a dielectric-barrier discharge technique. Methods: Citrus samples were stored under four different environmental conditions as follows: group A had cold storage with plasma treatment with a temperature of $6.2{\pm}1.0^{\circ}C$ and relative humidity (RH) of $93.4{\pm}8.2%$, group B had ambient-temperature storage with $22.9{\pm}2.3^{\circ}C$ and $82.1{\pm}4.5%$ RH, group C ambient-temperature storage with plasma treatment with $25.3{\pm}2.2^{\circ}C$ and $90.0{\pm}2.8%$ RH, and group D had cold storage with $5.7{\pm}1.0^{\circ}C$ and $93.4{\pm}6.5%$ RH. Results: As a result of citrus surface sterilization by plasma treatment, treatment groups A and C together showed an average of 16.1 CFU/mL of mold colonies, while control groups B and D showed an average of $2.2{\times}10^2CFU/mL$ or approximately 13 times greater than the treatment groups. Regarding the mean concentration of aerobic bacteria colonies, the treatment groups (A and C) and control groups (B and D) showed an average of 7.1 CFU/mL and $1.9{\times}10^3CFU/mL$, respectively. This is approximately a 270-fold difference in the concentration of pathogen colonies between treatment and control groups. Conclusions: The results showed the potential of nonthermal plasma treatment for citrus storage in enhancing storage duration and quality preservation.

• Journal of Microbiology and Biotechnology
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• 제14권2호
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• pp.276-283
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• 2004

Screening was performed to isolate cellulose-producing microorganisms from the Korean traditional fermented persimmon vinegar. The resulting strain, KJ $145^{T}$, was then taxonomically investigated by phenotypic characterization, particularly chemotaxonomic, and by phylogenetic inference based on a 16S rDNA sequence analysis including other related taxa. Strain KJ $145^{T}$ was found to grow rapidly and form pale white colonies with smooth to rough surfaces on a GYC agar. Strain KJ $145^T$ also produced acetate from ethanol, and was tolerable to 10% ethanol in SM medium. In a static culture, a thick cellulose pellicle was produced, and in GYC broth, the strain grew at temperatures ranging from 28 to $40^\circ{C}$ with an optimum pH of 4.0. The genomic DNA G+C content of strain KJ $145^T$ was 61.9 mol%, and the predominant ubiquinone was Q 10 as the major quinone and Q9 as the minor quinone. The major cellular fatty acids were $C_{16:0}$ and the sum in feature 7 ($C_{18:1}$ w9c, w12t and/or w7c). A 16S rRNA-targeted oligonucleotide probe specific for strain KJ $145^T$was constructed, and the phylogenetic position of the new species was derived from a 16S rDNA-based tree. When comparing the 16S rDNA nucleotide sequences, strain KJ $145^T$ was found to be most closely related to G. hansenii LMG $1527^T$ (99.2%), although KJ $145^T$ was still distinct from G. hansenii LMG $l527^T$ and G. xylinus LMG $1515^T$ in certain phenotypic characteristics. Therefore, on the basis of 16S rDNA sequences and taxonomic characteristics, it is proposed that strain KJ $145^T$ should be placed in the genus Gluconacetobacter as a new species, Gluconacetobacter persimmonis sp. nov., under the type-strain KJ $145^T$ (=KCTC =$10175BP^T$=KCCM=$10354^T$).

• Journal of Microbiology
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• 제35권4호
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• pp.284-289
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• 1997

A Gram (-), rod-shaped bacterium $2.3{\sim}2.8{\times}0.45{\mu}m$ in size which exhibited growth-inhibiting effects against a cyanobacterium (Anabaena cylindrica) was isolated from Daechung Dam Reservoir. This isolate was identified as Moraxella sp. and designated Moracella sp. CK-1. Hollow zones formed around bacterial colonies on the cyanobacterial lawn. In a mixed-culture of A. cylindrica and the isolate, each microorganism grew inverse-proportionally, and the cyanobacterial vegetative cells completely disappeared within 24 hours. On treatment with Moraxella sp. CK-1, cell walls of A. cylindrica disappeared, but sheathes remained in a more electron dense form. The unit membrane such as thylakoidal membrane was stable to bacterial lysing activity. This bacterium showed a broad action spectrum against cyanobacteria. The growth-inhibiting activity of Moracella sp. CK-1 against A. cylindrica is believed to be performed through the excretion of active substances.

• KSBB Journal
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• 제13권3호
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• pp.331-335
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• 1998

Erythritol is a four-carbon sugar alcohol with a low calorific value and non-cariogenicity. Erythritol is a new functional sweetener which can be used as sugar alternative. Erytheitol dose not cause discomfort such as diarrhoea and flatulence upon ingestion. The purpose of this study is to develope a novel process of erythritol economically in a large scale. To obtain a high erythritol producer, we have screened 3500 colonies from molasses, honey and honey combs. We have selected 40 erythritol-producing microorganisms, one of which yields 140g/L erythritol in 40% glucose medium. We have tested this strain in 5L fermentor to examine the fermentation characteristics. Results of fermentation show that the erythritol production was about 1.4g/L$.$hr in 400g/L glucose media with a 42% conversion. Further improvements require mutation for a higher producer, process optimization to reduce glycerol, and suppression of excessive foaming.

• 한국수정란이식학회지
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• 제28권1호
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• pp.49-55
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• 2013

The objective of this study was to evaluate several types of uterine bacteria in Hanwoo. uterine bacteria from randomly selected 5 uterus was collected by flushing methods into a sterilized 1.5 ml centrifuge tube and was inoculated onto MacConkey agar and blood agar, respectively. After being incubated for 5% $CO_2$, aerobic or anaerobic condition at $37^{\circ}C$ during 48h, bacterial colonies were selected and re-inoculated onto blood agar plates. Re-cultured colonies were identified by Gram staining and finally identified using Vitek system. The identified bacteria were Staphylococcus lentus, Staphylococcus sciuri, Staphylococcus vitulinus, Staphylococcus warneri of Gram (+) and Rhizobium radiobacter, Sphingomonas paucimobilis of Gram (-) bacteria. Although, pathogenicity of identified bacteria was unclear, the bacteria can have an effect on the uterine microenvironment. Therefore, repetitive research will be required to determine the effects of bacteria in cattle exposed to a various environment.

• Restorative Dentistry and Endodontics
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• 제39권4호
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• pp.258-264
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• 2014

Objectives: This in vitro study aimed to investigate the ability of Candida albicans (C. albicans) and Enterococcus faecalis (E. faecalis) to penetrate dentinal tubules of instrumented and retreated root canal surface of split human teeth. Materials and Methods: Sixty intact extracted human single-rooted teeth were divided into 4 groups, negative control, positive control without canal instrumentation, instrumented, and retreated. Root canals in the instrumented group were enlarged with endodontic instruments, while root canals in the retreated group were enlarged, filled, and then removed the canal filling materials. The teeth were split longitudinally after canal preparation in 3 groups except the negative control group. The teeth were inoculated with both microorganisms separately and in combination. Teeth specimens were examined by scanning electron microscopy (SEM), and the depth of penetration into the dentinal tubules was assessed using the SMILE view software (JEOL Ltd). Results: Penetration of C. albicans and E. faecalis into the dentinal tubules was observed in all 3 groups, although penetration was partially restricted by dentin debris of tubules in the instrumented group and remnants of canal filling materials in the retreated group. In all 3 groups, E. faecalis penetrated deeper into the dentinal tubules by way of cell division than C. albicans which built colonies and penetrated by means of hyphae. Conclusions: Microorganisms can easily penetrate dentinal tubules of root canals with different appearance based on the microorganism size and status of dentinal tubules.

• 한국미생물·생명공학회지
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• 제48권4호
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• pp.539-546
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• 2020

A cellulolytic bacterial strain, S2-3, was isolated from sea water collected in Jeju island, Republic of Korea. The strain was aerobic and gram negative, and formed yellow colored colonies on marine agar medium. S2-3 cells were long rod-shaped, 0.5 × 0.25 ㎛ (width x length) in size, and did not have flagella. The optimal growth conditions for S2-3 were 30-35℃ and pH 6.5-7.0. Analysis of the 16S rRNA gene sequence of S2-3 revealed that it had the highest identity with those of Seonamhaeicola algicola Gy8 (97.08%), Hyunsoonleella udonensis JG48 (95.01%), and Aestuariibaculum scopimerae I-15 (94.86%). In phylogenetic analysis, S2-3 formed the same clade as S. algicola Gy8, implying that S2-3 belongs to the genus Seonamhaeicola. The major fatty acids (>10%) comprised C15:1 iso G (22.29%), C15:0 iso (17.71%), C17:0 iso 3OH (16.06%), and C15:0 iso 3OH (10.7%), resulting in quite different ratio of the component from those of S. algicola Gy8. Moreover, its biochemical characteristics, including acid production and enzyme activities, were different from those of S. algicola Gy8. Therefore, putting all these results together, we concluded S2-3 is distinct species from S. algicola Gy8, and thus named it Seonamhaeicola sp. S2-3. In liquid culture, S2-3 produced extracellular cellulases that can hydrolyze cellulose or cellooligosaccharides into cellobiose, which is a good enzyme resource that deserves further research.

• 한국융합학회논문지
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• 제9권12호
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• pp.129-135
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• 2018

본 연구는 치과에서 사용하는 기본기구인 Mirror, Explore, Pincette에서 멸균 후 시간이 경과함에 따른 미생물 오염도를 알아보고자 하였다. 치과에서 주로 사용하고 있는 Mirror, Explorer, Pincette을 10개씩 포장하여 각 기구별 60개의 샘플을 사용하였다. 미생물 오염도는 멸균직후, 2주차, 3주차, 4주차, 5주차, 6주차에 10개의 샘플을 수거하여 건조필름배지(3M Petrifilm Plates)를 이용하여 검사하였다. 멸균 직후인 0주차에는 모든 기구에서 균이 검출 되지 않았으나, 6주차에서는 Mirror, Explorer, Pincette에서 각각 2개의 기구에서 균이 검출 되었다. Mirror에서는 실험 2주차와 4주차에서 평균 2-4개의 colony가 관찰 되었고, Explorer는 5주부터 평균 1-2개의 colony가 발견되기 시작하였으며, Pincette에서는 5주차까지 colony가 발견되지 않았으나, 6주차에서는 평균 1-2개의 colony가 발견 되었다. 이 결과를 바탕으로 보다 안전한 기구사용과 더불어 멸균기구의 유효기간의 필요성을 제시하고자 한다.