Characterization of an Isolate That Uses Vinyl Chloride as a Growth Substrate under Aerobic Conditions
Characterization of an Isolate That Uses Vinyl Chloride as a Growth Substrate under Aerobic Conditions
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在有氧条件下使用氯乙烯作为生长底物的分离株的表征
DOI：
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发表时间：
2000
影响因子：
4.4
通讯作者：
D. Freedman
中科院分区：
文献类型：
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作者：
M. Verce;R. Ulrich;D. Freedman
以氯乙烯（VC）为唯一有机碳源和电子供体，建立了一种好氧富集培养体系。VC浓度高达7.3 mM的生物降解没有明显的抑制。当硝酸盐作为电子受体时，VC的使用没有发生。从富集培养物中获得了一株革兰氏阴性、棒状、运动型分离株，并根据生化特征和16 S rRNA基因序列鉴定为铜绿假单胞菌，命名为MF 1菌株。当MF 1在VC上生长时，观察到的产率为0.20 mg总悬浮固体（TSS）/mg VC。乙烯、乙酸盐、乙醛酸盐和乙醇酸盐也作为生长底物，而乙烷、氯乙酸盐、乙醇醛和苯酚则不作为生长底物。化学计量释放的氯化物和VC消费后的可溶性代谢物的最小积累表明，VC的主要命运是矿化和纳入细胞材料。MF 1在至少24天后恢复消耗VC，而不像各种分枝杆菌在缺乏VC的情况下在短暂时间后失去VC降解能力。当缺氧2.5天时，MF 1没有恢复在VC上生长的能力，并且一部分VC转化为VC-环氧化物。乙炔抑制VC消耗MF 1，表明参与的单加氧酶在VC代谢的初始步骤。MF 1的最大VC利用率为0.41 μmol VC/mg TSS/d，最大比生长率为0.0048/d，Monod半饱和系数为0.26 μM。当MF 1在乙烯上生长时，发生更高的产率和更快的动力学。当在乙烯上生长时，MF 1能够切换到VC作为底物而没有滞后。因此，似乎可行的生长MF 1上无毒的基板，然后将其应用到环境中，不表现出有氧生物降解VC的能力。
ABSTRACT An aerobic enrichment culture was developed by using vinyl chloride (VC) as the sole organic carbon and electron donor source. VC concentrations as high as 7.3 mM were biodegraded without apparent inhibition. VC use did not occur when nitrate was provided as the electron acceptor. A gram-negative, rod-shaped, motile isolate was obtained from the enrichment culture and identified based on biochemical characteristics and the sequence of its 16S rRNA gene asPseudomonas aeruginosa, designated strain MF1. The observed yield of MF1 when it was grown on VC was 0.20 mg of total suspended solids (TSS)/mg of VC. Ethene, acetate, glyoxylate, and glycolate also served as growth substrates, while ethane, chloroacetate, glycolaldehyde, and phenol did not. Stoichiometric release of chloride and minimal accumulation of soluble metabolites following VC consumption indicated that the predominant fate for VC is mineralization and incorporation into cell material. MF1 resumed consumption of VC after at least 24 days when none was provided, unlike various mycobacteria that lost their VC-degrading ability after brief periods in the absence of VC. When deprived of oxygen for 2.5 days, MF1 did not regain the ability to grow on VC, and a portion of the VC was transformed into VC-epoxide. Acetylene inhibited VC consumption by MF1, suggesting the involvement of a monooxygenase in the initial step of VC metabolism. The maximum specific VC utilization rate for MF1 was 0.41 μmol of VC/mg of TSS/day, the maximum specific growth rate was 0.0048/day, and the Monod half-saturation coefficient was 0.26 μM. A higher yield and faster kinetics occurred when MF1 grew on ethene. When grown on ethene, MF1 was able to switch to VC as a substrate without a lag. It therefore appears feasible to grow MF1 on a nontoxic substrate and then apply it to environments that do not exhibit a capacity for aerobic biodegradation of VC.