프로판 및 부탄 이용 미생물에 의한 휘발유 첨가제 MTBE의 동시분해

Cometabolic Biodegradation of Fuel Additive Methyl tert-Butyl Ether(MTBE) by Propane- and Butane-Oxidizing Microorganisms

축내유류오염지역 토양에서 propane과 butane을 탄소원으로 이용하여 분리된 Nocardia SW3를 대상으로 가스기질농도, 온도, pH 변화에 따른 영향, 그리고 MTBE 공대사 분해 특성을 조사하였다. 초기농도변화에 따른 기질분해속도를 비교하면 propane 및 butane이 70μmol일때 각각 30.6, 25.4(nmol/min/mg protein)으로 관찰되어 빠른 기질이용율을 보여주었으며, 최적온도 및 pH 조건은 30℃, 7이었으며. 실험조건인 온도 15℃~35℃, pH 5~8 범위내에서 약간의 차이는 있지만 전반적으로 propane과 butane이 효율적으로 이용되었다. Nocardia SW3를 대상으로 propane 및butane이 탄소원으로 이용될 때 MTBE 분해특성을 비교ㆍ평가한 결과 propane 및 butane의 MTBE 분해활성도는 유사하였으며, 가스기질이 탄소원으로 이용시 MTBE의 분해량을 나타내는 transformation yield(Ty)는 propane과butane의 경우 각각 46.7, 35.0(nmol MTBE degrade/μmol substrate utilized), transformation capacity(Tc)는 실험결과 각각 320, 280(nmol MTBE degraded/mg biomass used)로 나타났다. 또한 MTBE 부산물로 TBA가 검출되었으며, TBA의 지속적인 분해를 관찰하였다.

A gas-substrate degrading bacterium. Nocardia SW3, was isolated from the gasoline contaminated aquifer using propane and butane as carbon and energy sources. We have examined the effects of substrate concentration, temperature and pH on the gas substrate degradation as well as MTBE cometabolic degradation. The result for the effect of substrate concentration showed that the maximum degradation rates of propane and butane were 30.6 and 25.4 (nmol/min/mg protein) at 70μmol, respectively. The optimum temperature and pH for the degradation of gas substrate were 30°C and 7, respectively. Substrate degradation activity, however, was still active in broad range of pH from 5 to 8 and temperature between 15°C and 35°C. The degradation activity of Nocardia SW3 for the MTBE was similar to the both substrates. The observed maximal transformation yields (Ty) were 46.7 and 35.0 (nmol MTBE degraded/μmol substrate utilized), and the maximal transformation capacities (Tc) were 320 and 280 (nmol MTBE degraded/mg biomass used) for propane and butane oxidizing activity on MTBE, respectively. And also, TBA was detected as by-product of MTBE and it was continuously degraded further.