Diversity in kinetics of trichloroethylene-degrading activities exhibited by phenol-degrading bacteria
Diversity in kinetics of trichloroethylene-degrading activities exhibited by phenol-degrading bacteria
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DOI：
10.1007/s002530000500
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发表时间：
2001-03-01
影响因子：
5
通讯作者：
Watanabe, K
中科院分区：
文献类型：
--
作者：
Futamata, H;Harayama, S;Watanabe, K
分析了13种苯酚降解菌表达的苯酚和三氯乙烯（TCE）降解活性的全细胞动力学。TCE的K-s （Haldane方程中的表观亲和常数）值出乎意料地多样化，范围从11 muM到800 muM以上。在所有被分析的细菌中，苯酚的V-max/K-s值比TCE的值高3个数量级，这表明这些细菌优先降解苯酚而不是TCE。苯酚的K-s值与TCE的K-s值呈正相关，即苯酚的Kh值高的细菌，其TCE的K-s值也高，反之亦然。通过K-s值的比较，可以将这些细菌分为三种类型，即低、中、高K-s型。在3.8 muM时，TCE的伪一级降解速率常数足以快速区分三种细菌。当细菌在初始浓度为2 mM的苯酚上生长时，低k -s细菌代表的睾酮Comamonas testosterone菌株R5在3.8 muM时完全降解TCE，而高k -s细菌代表的菌株P-8则没有。这两种细菌的混合培养在相同的条件下降解TCE很差，其中P-8超过R5。这些结果表明，低k -s细菌应该选择性培养，以有效地修复tce污染地下水。
Whole-cell kinetics of phenol- and trichloroethylene (TCE)-degrading activities expressed by 13 phenol-degrading bacteria were analyzed. The K-s (apparent affinity constant in Haldane's equation) values for TCE were unexpectedly diverse, ranging from 11 muM to over 800 muM. The V-max/K-s values for phenol were three orders of magnitude higher than the values for TCE in all bacteria analyzed, suggesting that these bacteria preferentially degrade phenol rather than TCE. A positive correlation between K-s for phenol and K-s for TCE was found, i.e., bacteria exhibiting high Kh values for phenol showed high K-s values for TCE, and vice versa. A comparison of the K-s values allowed grouping of these bacteria into three types, i.e., low-, moderate- and high-K-s types. Pseudo-first-order degradation-rate constants for TCE at 3.8 muM were found to be adequate to rapidly discriminate among the three types of bacteria. When bacteria were grown on phenol at the initial concentration of 2 mM, Comamonas testosteroni strain R5, a representative of low-K-s bacteria, completely degraded TCE at 3.8 muM, while strain P-8, a representative of high-K-s bacteria, did not. A mixed culture of these two bacteria poorly degraded TCE under the same conditions, where P-8 outgrew R5. These results suggest that low-K-s bacteria should be selectively grown for effective bioremediation of TCE-contaminated groundwater.