• 대한환경공학회지
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• 제29권3호
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• pp.283-288
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• 2007

연속회분식반응조(SBR) 공정에서 슬러지 체류시간(SRT)에 따른 중금속의 독성도 변화를 측정하였다. 중금속은 구리(Cu), 카드뮴(Cd) 및 아연(Zn)을 사용하였고, SRT는 $2\sim30$일로 변화시켰으며, 독성도는 INT-dehydrogenase 활성도의 변화로 측정하였다. 중금속의 농도가 증가함에 따라 독성도가 증가하였으며, Cu가 Zn 및 Cd 보다 독성도가 높았다. SRT를 변화시켰을 때 $IC_{50}$ 값이 Cu의 경우 $0.37\sim1.96$ mg/L의 범위를 나타내었으며, Cd의 경우는 $15.4\sim16.9$ mg/L를 나타내었다. 또한 Zn의 경우는 $9.70\sim23.4$ mg/L의 범위를 나타내었다. Cu와 Zn의 경우, SRT가 증가함에 따라 독성이 감소하였으며, 이는 긴 SRT에서 세포외 중합체의 농도가 증가하기 때문인 것으로 판단된다. 따라서 중금속을 포함한 산업폐수를 처리하는 SBR 공정에서 SRT를 길게 운영하는 것이 바람직할 것으로 판단된다.

• 대한환경공학회지
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• 제30권10호
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• pp.1021-1027
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• 2008

본 연구에서는 비점오염물질을 처리하기 위해 생물막 공정이 도입되었다. 반응기내의 생물막의 성장으로 위해 세라믹 담체가 사용되었으며, 담체의 충전률은 각각 5% 및 15(v/v)%였다. 이후, 반응기는 각각 0, 5, 10, 15일의 무강우기간에 따라 회분식으로 운전되었다. COD 및 NH$_4{^+}$-N의 제거효율이 담체 충전률, 온도 및 무강우기간에 따라 조사되었으며, 추가적으로 polymerase chain reaction (PCR)-denaturing gel gradient electrophoresis(DGGE)와 INT-dehydrogenase activity(DHA) test를 통하여 미생물 군집 및 활성도가 해석되었다. 운전 결과, 무강우기간이 늘어남에도 충전률에 관계없이 COD의 제거는 안정적으로 일어났다. COD는 25$^{\circ}C$에서는 6$\sim$8 hr, 10$^{\circ}C$에서는 약 15 hr의 반응시간이 필요하였다. DGGE 분석 결과, 무강우기간이 늘어남에 따라 식종 슬러지에서 발견되는 미생물에서 저니토에서 주로 발견되는 미생물로 변화됨을 확인할 수 있었다. 또한 INT-DHA법에 의한 미생물의 활성도 측정 결과, 15일의 무강우기간에도 활성도의 감소는 관찰되지 않았다.

• 대한환경공학회지
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• 제22권11호
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• pp.1969-1976
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• 2000

폐수의 복합독성과 다수의 미지 화합물의 영향을 평가하는 것은 많은 시간이 요구되고 분석상 어려움이 존재하는 경우가 많다. 그러므로 폐수중 독성을 나타내는 원인물질의 탐색과 처리효과를 평가하기 위한 방법을 확립하는 것이 절실히 요구된다. 본 연구에서는 질산화 저해제를 이용하여 혼합미생물중 질산화 미생물과 종속영양미생물을 구분하여 암모니아 저해도 실험을 수행하였으며, 이때 저해도는 dehydrogenase activity(DHA)를 이용한 미생물활성도의 차이로서 평가하였다. DHA에 의한 암모니아 저해 연구는 총 암모니아의 영향, 유리 암모니아의 영향, 질산화 미생물과 종속영양미생물의 암모니아 저해도에 대해 각각 평가되었다. 암모니아 독성은 총 암모니아 농도와 pH가 증가할수록 크게 나타나 유리 암모니아의 역할이 중요하게 작용함이 밝혀졌으나 미생물의 DHA는 총 암모니아와 유리 암모니아가 함께 고려되어야 정확히 평가될 수 있었다. 3.000mg/L 이상의 고농도의 암모니아에서는 질산화 미생물이 종속영양미생물 보다 심한 저해를 받는 것으로 나타났다.

• 동의생리병리학회지
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• 제17권4호
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• pp.996-1001
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• 2003

It is well known that oxidative stress of reactive oxygen species(ROS) may be a causative factor in the pathogenesis of bone disorder. The purpose of this study was to evaluate the cytotoxicity of oxidative stress. Cell viability by MTS assay or INT assay, activity of glutathione peroxidase(GPx), lipid peroxidation(LPO) activity and cell viablity. And also protctive effect of glutamate receptors against ROS-induced osteotoxicity was examined by protein synthesis, alkaline phosphatase (ALP) activity and lactate dehydrogenase (LDH) activity in cultured rat osteoblasts and osteoclasts. XO/HX decreased cell viability and GPx activity, protein synthesis and ALP activity, but increased LPO activity and LDH activity. In the protective effect, N-methyl-D-aspartate (NMDA) receptor antagonists or AMPA/kainate receptor antagonists such as D-2-amino-5-phosphonovaleric acid (APV), 7-chlorokynurenic acid (CKA), 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and 6,7-dinitroquinoxaline-2,3-dione (DNQX), NMDA receptor antagonists but AMPA/kainate receptor antagonists showed protective effect on xanthine oxidase (XO) and hypoxanthine (HX) in these cultures by the increse of protein synthesis, ALP activity.

• Journal of Microbiology and Biotechnology
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• 제14권2호
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• pp.350-355
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• 2004

Sulforhodamine B (SRB) assay is a rapid, sensitive, and inexpensive method for measuring cell proliferation and chemosensitivity. However, the lactate dehydrogenase (LDH) release assay is generally used to measure cytototoxicity of infectious microorganisms against host cells. In this study, we investigated the possibility of applying the SRB assay to determine cytotoxicity for infectious microorganisms, and compared the results with those obtained by the LDH release assay. We used Vibrio vulnificus as a model of infectious microorganisms. The SRB assay showed that V vulnificus strongly induced cytotoxic activity against human intestinal cells, Caco-2 and INT-407 cells. The degree of cytotoxicity closely correlated with infection time and number ratios of V. vulnificus to intestinal cells (MOI, multiplicity of infection). Furthermore, cytotoxicity values obtained by SRB assay correlated well with results obtained by the LDH release assay, and both assays gave a linear response with respect to MOI Heat-inactivation of V. vulnificus for 35 min at $60^{\circ}C$ did not induce cytotoxic activity, indicating that viability of V. vulnificus is crucial for cytotoxic activity against intestinal cells. Although both assays are suitable as cytotoxicity endpoints, the SRB assay is recommended for measuring cytotoxicity of infectious microorganisms against host cells because of its significantly lower cost and more stable endpoint than the LDH release assay.

• Environmental Engineering Research
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• 제19권4호
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• pp.309-316
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• 2014

The water quality improvement of golf course ponds, as representative stagnant stream channels, was evaluated by applying a biological activated carbon (BAC) process composed of four consecutive activated carbon reactors. The study was performed from autumn to winter in order to evaluate the feasibility of the BAC process under low temperature conditions. In the study, water quality of pond A (target pond) and pond B (reference pond) were monitored. Pond water was pumped into the BAC process, and was then returned to the pond after treatment. The optimal conditions were determined to be 2 hr of empty bed contact time (EBCT) at a temperature above $4^{\circ}C$, in which improvements of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) of pond A compared to pond B were 3.62%, 3.48% and 1.81%, respectively. On the other hand, as the temperature was below $4^{\circ}C$, some degree of water quality improvement was achieved even when EBCT were 1 or 0.5 hr, suggesting that the BAC process can be successfully applied for the improvement of pond water quality in winter months. The values of biomass concentration and microorganism activity in each condition were highest where 2 hr of EBCT was applied at a temperature above $4^{\circ}C$, but values were similar throughout all treatment conditions, and thus, adsorption is considered to be the dominant factor affecting process efficiency. From the denaturing gel gradient electrophoresis (DGGE) results, no significant differences were observed among the activated carbon reactors, suggesting that the number of reactors in the system could be decreased for a more compact application of the system.