Lee Eun Young, Jun Youn Shin, Cho Kyung-Suk, Ryu Hee Wook
National Subsurface Environmental Research Laboratory, Ewha Womans University, Seoul, Korea.
J Air Waste Manag Assoc. 2002 Apr;52(4):400-6. doi: 10.1080/10473289.2002.10470796.
Stenotrophomonas maltophilia T3-c, isolated from a biofilter for the removal of benzene, toluene, ethylbenzene, and xylene (BTEX), could grow in a mineral salt medium containing toluene, benzene, or ethylbenzene as the sole source of carbon. The effect of environmental factors such as initial toluene mass, medium pH, and temperature on the degradation rate of toluene was investigated. The cosubstrate interactions in the BTEX mixture by the isolate were also studied. Within the range of initial toluene mass (from 23 to 70 pmol), an increased substrate concentration increased the specific degradation of toluene by S. maltophilia T3-c. The toluene degradation activity of S. maltophilia T3-c could be maintained at a broad pH range from 5 to 8. The rates at 20 and 40 degrees C were 43 and 83%, respectively, of the rate at 30 degrees C. The specific degradation rates of toluene, benzene, and ethylbenzene by strain T3-c were 2.38, 4.25, and 2.06 micromol/g-DCW/hr. While xylene could not be utilized as a growth substrate by S. maltophilia T3-c, the presence of toluene resulted in the cometabolic degradation of xylene. The specific degradation rate of toluene was increased by the presence of benzene, ethylbenzene, or xylene in binary mixtures. The presence of toluene or xylene in binary mixtures with benzene increased the specific degradation rate of benzene. The presence of ethylbenzene in binary mixtures with benzene inhibited benzene degradation. The presence of more than three kinds of substrates inhibited the specific degradation rate of benzene. All BTEX mixtures, except tri-mixtures of benzene, ethylbenzene, and xylene or mixtures of all four substrates, had little effect on the degradation of ethylbenzene by S. maltophilia T3-c. The utilization preference of the substrates by S. maltophilia T3-c was as follows: ethylbenzene was degraded fastest, followed by toluene and benzene. However, the specific degradation rates of substrates, in order, were benzene, toluene, and ethylbenzene.
嗜麦芽窄食单胞菌T3-c是从用于去除苯、甲苯、乙苯和二甲苯（BTEX）的生物滤池中分离得到的，它能够在以甲苯、苯或乙苯作为唯一碳源的无机盐培养基中生长。研究了初始甲苯质量、培养基pH值和温度等环境因素对甲苯降解率的影响。还研究了该分离株在BTEX混合物中的共底物相互作用。在初始甲苯质量范围（23至70 pmol）内，底物浓度的增加提高了嗜麦芽窄食单胞菌T3-c对甲苯的比降解率。嗜麦芽窄食单胞菌T3-c的甲苯降解活性在5至8的较宽pH范围内均可维持。20℃和40℃时的降解率分别为30℃时降解率的43%和83%。菌株T3-c对甲苯、苯和乙苯的比降解率分别为2.38、4.25和2.06 μmol/g-DCW/小时。虽然嗜麦芽窄食单胞菌T3-c不能利用二甲苯作为生长底物，但甲苯的存在导致了二甲苯的共代谢降解。二元混合物中苯、乙苯或二甲苯的存在提高了甲苯的比降解率。甲苯或二甲苯与苯的二元混合物的存在提高了苯的比降解率。乙苯与苯的二元混合物的存在抑制了苯的降解。三种以上底物的存在抑制了苯的比降解率。除苯、乙苯和二甲苯的三元混合物或所有四种底物的混合物外，所有BTEX混合物对嗜麦芽窄食单胞菌T3-c降解乙苯的影响很小。嗜麦芽窄食单胞菌T3-c对底物的利用偏好如下：乙苯降解最快，其次是甲苯和苯。然而，底物的比降解率依次为苯、甲苯和乙苯。
