• Journal of Microbiology and Biotechnology
• /
• 제24권11호
• /
• pp.1574-1582
• /
• 2014

Bacteria recognize changes in their population density by sensing the concentration of signal molecules, N-acyl-homoserine lactones (AHLs). AHL-mediated quorum sensing (QS) plays a key role in biofilm formation, so the interference of QS, referred to as quorum quenching (QQ), has received a great deal of attention. A QQ strategy can be applied to membrane bioreactors (MBRs) for advanced wastewater treatment to control biofouling. To isolate QQ bacteria that can inhibit biofilm formation, we isolated diverse AHL-degrading bacteria from a laboratory-scale MBR and sludge from real wastewater treatment plants. A total of 225 AHL-degrading bacteria were isolated from the sludge sample by enrichment culture. Afipia sp., Acinetobacter sp. and Streptococcus sp. strains produced the intracellular QQ enzyme, whereas Pseudomonas sp., Micrococcus sp. and Staphylococcus sp. produced the extracellular QQ enzyme. In case of Microbacterium sp. and Rhodococcus sp., AHL-degrading activities were detected in the whole-cell assay and Rhodococcus sp. showed AHL-degrading activity in cell-free lysate as well. There has been no report for AHL-degrading capability in the case of Streptococcus sp. and Afipia sp. strains. Finally, inhibition of biofilm formation by isolated QQ bacteria or enzymes was observed on glass slides and 96-well microtiter plates using crystal violet staining. QQ strains or enzymes not only inhibited initial biofilm development but also reduced established biofilms.

• 유기물자원화
• /
• 제9권2호
• /
• pp.45-51
• /
• 2001

맥반석은 용액중의 철, 구리, 카드뮴과 아연 등 중금속 이온에 대해 제거효과를 나타냈으며, 그 중에서도 철과 동의 제거가 가장 뚜렷하였다. 이런 중금속의 제거는 맥반석에 포함되어 있는 칼슘 등 금속과의 이온교환에 의해 이루지는 것으로 나타났다. 맥반석은 황화수소와 암모니아 등 악취물질에 대해서도 뚜렷한 제거효과가 있으며 E. coli에 대해 항균효과가 있는 것으로 나타났다. 그리고 Nocardioides sp. PNP101를 이용한 4-nitrophenol의 분해와 Strain CJl과 Rhodococcus sp. DNP 505를 이용한 2,4-dinitrophenol의 분해를 뚜렷하게 촉진하는 것으로 나타났다.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2005년도 생물공학의 동향(XVI)
• /
• pp.263-263
• /
• 2005

• 한국미생물생명공학회:학술대회논문집
• /
• 한국미생물생명공학회 2005년도 2005 Annual Meeting & International Symposium
• /
• pp.336-336
• /
• 2005

• 한국생명과학회:학술대회논문집
• /
• 한국생명과학회 2005년도 국제학술심포지움 The 44th Annual Meeting of Korean Society for Life Science
• /
• pp.166-167
• /
• 2005

• Journal of Microbiology and Biotechnology
• /
• 제12권1호
• /
• pp.39-45
• /
• 2002

Activity staining on the native polyacrylamide gel electrophoresis (PAGE) of a cell-free extract of Rhodococcus sp. TK6, grown in media containing alcohols as the carbon source, revealed at least seven isozyme bands, which were identified as alcohol dehydrogenases that oxidize cyclohexanol to cyclohexanone. Among the alcohol dehydrogenases, cyclohexanol dehydrogenase II (CDH II), which is the major enzyme involved in the oxidation of cyclohexanol, was purified to homogeneity. The molecular mass of the CDH II was determined to be 60 kDa by gel filtration, while the molecular mass of each subunit was estimated to be 28 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The CDH II was unstable in acidic and basic pHs, and rapidly inactivated at temperatures above $40^{\circ}C$ . The CDH II activity was enhanced by the addition of divalent metal ions, like $Ba^2+\;and\;Mg^{2+}$. The purified enzyme catalyzed the oxidation of a broad range of alcohols, including cyclohexanol, trans-cyclohexane-1,2-diol, trans-cyclopentane-l,2-diol, cyclopentanol, and hexane-1,2-diol. The $K_m$ values of the CDH II for cyclohexanol, trans-cyclohexane-l,2-diol, cyclopentanol, trans-cyclopentane-l,2-diol, and hexane-l,2-diol were 1.7, 2.8, 14.2, 13.7, and 13.5 mM, respectively. The CDH II would appear to be a major alcohol dehydrogenase for the oxidation of cyclohexanol. The N-terminal sequence of the CDH II was determined to be TVAHVTGAARGIGRA. Furthermore, based on a comparison of the determined sequence with other short chain alcohol dehydrogenases, the purified CDH II was suggested to be a new enzyme.

• 한국입자에어로졸학회지
• /
• 제7권1호
• /
• pp.9-19
• /
• 2011

The effects of different transient loading conditions on xylene removability and bacterial activity were evaluated in the polyurethane (PU) biofilter inoculated with Rhodococcus sp. EH831: BF1 (the control) was operated under continuous and constant loading ($200{\pm}50ppm$); BF2 under continuous and constant loading after a 2-week long-term shutdown; BF3 under discontinuous (8 h on/16 h off on weekdays and a 2 day-shutdown at weekends); and constant loading BF4 under discontinuous and high loading ($700{\pm}300ppm$); and BF5 under continuous and fluctuating loading (high loading for 8 h and low loading ($75{\pm}25ppm$) for 16 h on weekdays and low loading at weekends). Xylene removal efficiencies in the BF1, BF2, BF3, and BF5 were ranged 83-89%, indicating that 2-week long-term shutdown, intermittent or fluctuant loading condition did not significantly influence the biofilter performance. However, discontinuous and high load condition (BF4) caused to deteriorate xylene removability to 52%. Rhodococcus sp. EH831 could be maintained at $10^9{\sim}10^{10}CFU/g-dry$ PU under 5 kinds of loading conditions. The result of polymerase chain reaction-terminal-restriction fragment length polymorphism showed that there was no significant change in bacterial community structures by different loading conditions.

• 한국환경농학회지
• /
• 제31권2호
• /
• pp.185-191
• /
• 2012

본 연구에서는 산업폐수로부터 분리한 3가지 종의 인 제거율을 확인하였다. 3 가지 분리된 균을 동정한 결과 A1균은 Stenotrophomonas maltophilia strain CUPS 3, A2균은 Rhodococcus erythropolis strain Sco-C01, A3균은 Bacillus sp. 3434BRRJ이었다. 3 가지 분리된 균의 인 제거 및 경유분해를 확인한 결과 인 제거율은 Bacillus sp. 3434BRRJ > Stenotrophomonas maltophilia strain CUPS균 > Rhodococcus erythropolis strain Sco-C01균 순으로 높은 것으로 나타났으며 제거율은 약 99%, 50%, 20%로 확인되었다. 따라서 이 후 실험은 인 제거율이 가장 높았던 Bacillus sp. 3434BRRJ를 가지고 실험하였다. Bacillus sp. 3434BRRJ의 인 제거를 확인하기 위하여 온도별(15, 25 그리고 $30^{\circ}C$), 인 농도별(20, 30 그리고 40 mg/L) 그리고 산소조건(호기, 혐기/호기조건) 및 탄소원을 달리하여 실험하였다. 그 결과Bacillus sp. 3434BRRJ는 $30^{\circ}C$에서 인 제거가 가장 좋았으며 20 mg/L의 인은 약 99% 처리하였고 혐기조건을 거치고 탄소원으로 acetate와 glucose를 혼합하여 처리하였을 때 가장 효율이 좋은 것으로 나타났다. 본 연구에서는 Bacillus sp. 3434BRRJ의 인 제거를 확인 하였다. 균의 생장이 높을수록 인의 제거율은 높았으며, 미생물을 이용한 환경오염물질의 제거에 있어서 가장 중요한 것은 미생물의 활성을 높이는 환경조건을 제공하는 것이다.

• 미생물학회지
• /
• 제46권1호
• /
• pp.109-111
• /
• 2010

다환 방향족 탄화수소(PAH; polycyclic aromatic hydrocarbon)는 발암성, 돌연변이 유발성, 유전독성을 지니기 때문에 인체위해성이 큰 물질로 알려져 있다. 기존 PAH 분해 미생물 탐색 방법중 독성이 강한 유기용매에 PAH를 용해시켜 미생물에 직접 분무하는 분무법, 미생물과 직접 혼합하는 한천중층법은 미생물 생장에 영향을 줄 뿐만 아니라, 특히 많이 쓰이는 분무법의 경우 분무되는 PAH의 양을 조절하기가 어렵고 멸균상태를 유지하기가 힘들다는 단점이 있다. 그래서 본 논문에서는 이와 같은 단점을 보완한 방법으로 승화법(Alley, Jeremy F. and Lewis R. Brown. 2000. Use of sublimation to prepare solid microbial media with water-insoluble substrates. Appl. Environ. Microbiol. 66, 439-442)을 도입하여 적용하였다. 그 결과 상용휘발유 및 태안유류유출지 시료로부터 분리한 350분리균주 중에서 7균주가 단일 PAH 또는 복수의 PAH 분해에 관여했다. 특히 Corynebacterium sp. SK20, Rhodococcus sp. TA24, Streptomyces sp. TA27은 시험한 pyene, phenanthrene, naphthalene에, Gordonia sp. H37는 pyrene, naphthalene에, Arthrobacter sp. S49는, naphthalene, phenanthrene에 활성이 있었다.

• 한국동물학회:학술대회논문집
• /
• 한국동물학회 1998년도 한국생물과학협회 학술발표대회
• /
• pp.171.2-171
• /
• 1998

No Abstract, See Full Text