Abstract
A BOD sensor was prepared with S. marcescens LSY4 and was applied for measurement of BOD values of a solution containing the standard organic pollutants. The sensor sensitivity was nearly independent of the culture time in the range of 9-16 hours. It was also affected little by the cell mass in the range of 0.22-0.75 mg $cm^{-2}$. A cyclic change in the solution pH in the range of 4-9 was accompanied by a reversible variation in the sensor sensitivity. However, the reversibility was lost when the solution pH became more acidic or more basic. Heavy metal ions lowered the sensor sensitivity, which took place more precipitously in the presence of $Cu^{2+}$ and $Ag^+$ rather than in the presence of $Zn^{2+}$ and $Cd^{2+}$. The reduction of the sensor sensitivity was significantly attenuated by loading heavy metal ion tolerance induced strain. The $Cu^{2+}$tolerance induced strain was more efficient for the attenuation than $Zn^{2+}$ and $Cd^{2+}$ tolerance induced strain.
S. marcescens LSY4가 충전된 BOD센서를 제작하여 표준오염물질을 포함한 수용액의 BOD를 측정하였다. 배양시간이 9∼16시간일 때에는 배양시간에 따른 BOD센서의 감응도에 큰 차이를 나타내지 않았으며, 균체량도 0.22~0.75mg $cm^{-2}$의 범위에서는 거의 동일한 센서의 감응도를 나타내었다. 수용액의 pH가 4~9사이로 변화할 경우 센서의 감응도가 가역적으로 변화하였으나 수용액이 더 산성이거나 더 염기성이 되면 센서의 감응도가 비가역적으로 저하되었다. 수용액에 중금속이온이 첨가되면 센서의 감응도가 감소하였으며, $Zn^{2+}$나 $Cd^{2+}$보다 $Cu^{2+}$혹은 $Ag^+$가 첨가되었을 때 센서의 감응도가 더 급격히 감소하였다. 중금속에 대한 내성이 유도된 균체를 충전하였을 때 중금속이온의 첨가에 따른 센서의 감응도 감소가 크게 완화되었으며, 이런 효과는 $Cd^{2+}$내성주보다 $Cu^{2+}$내성주에서 더 현저하였다.