Dehalorespiration with hexachlorobenzene and pentachlorobenzene by Dehalococcoides sp strain CBDB1
Dehalorespiration with hexachlorobenzene and pentachlorobenzene by Dehalococcoides sp strain CBDB1
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DOI：
10.1007/s00203-003-0607-7
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发表时间：
2003-12-01
影响因子：
2.8
通讯作者：
Adrian, L
中科院分区：
文献类型：
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作者：
Jayachandran, G;Görisch, H;Adrian, L
厌氧氯呼吸细菌Dehalococcoides sp.菌株CBDB 1以六氯苯和五氯苯为电子受体，以氢气为电子供体，进行节能过程。如果这些化合物作为十六烷中的溶液提供，则先前用六氯苯或五氯苯作为电子受体生长Dehalocococcoides sp.菌株CBDB 1的尝试失败。然而，脱卤球菌属菌株CBDB 1在以晶体形式直接加入培养物中时能够与六氯苯或五氯苯一起生长。通过脱卤呼吸作用使Dehalococcoides sp.菌株CBDB 1生长，在六氯苯作为电子受体时，生长产量（Y）为2.1+/-0.24 g蛋白质/mol Cl-;在五氯苯作为电子受体时，生长产量为2.9+/-0.15 g/mol Cl-。将六氯苯还原脱氯为五氯苯，再将五氯苯转化为1，2，3，5-四氯苯和1，2，4，5-四氯苯的混合物。未检测到1，2，3，4-四氯苯的形成。六氯苯和五氯苯脱氯的最终产物为1，3，5-三氯苯、1，3-二氯苯和1，4-二氯苯，其形成比例约为3：2：5。如前所述，Dehalococcoides sp.菌株CBDB 1仅将1，2，3，5-四氯苯转化为1，3，5-三氯苯，将1，2，4，5-四氯苯仅转化为1，2，4-三氯苯。因此，该生物体催化两种不同的途径来使高氯化苯脱氯。在导致1，3，5-三氯苯的路线中，仅双侧氯取代基被去除，而在通过1，2，4-三氯苯导致1，3-和1，4-二氯苯的路线中，单侧氯取代基也被去除。还原脱卤酶活性的测量，使用不同的氯苯同系物作为电子受体预生长的全细胞表明，不同的还原脱卤酶可能会引起不同的电子受体。据我们所知，这是第一份报告描述还原脱氯的六氯苯和五氯苯通过脱卤呼吸的纯细菌培养。
The chlororespiring anaerobe Dehalococcoides sp. strain CBDB1 used hexachlorobenzene and pentachlorobenzene as electron acceptors in an energy-conserving process with hydrogen as electron donor. Previous attempts to grow Dehalococcoides sp. strain CBDB1 with hexachlorobenzene or pentachlorobenzene as electron acceptors failed if these compounds were provided as solutions in hexadecane. However, Dehalococcoides sp. strain CBDB1 was able to grow with hexachlorobenzene or pentachlorobenzene when added in crystalline form directly to cultures. Growth of Dehalococcoides sp. strain CBDB1 by dehalorespiration resulted in a growth yield (Y) of 2.1+/-0.24 g protein/mol Cl- released with hexachlorobenzene as electron acceptor; with pentachlorobenzene, the growth yield was 2.9+/-0.15 g/mol Cl-. Hexachlorobenzene was reductively dechlorinated to pentachlorobenzene, which was converted to a mixture of 1,2,3,5- and 1,2,4,5-tetrachlorobenzene. Formation of 1,2,3,4-tetrachlorobenzene was not detected. The final end-products of hexachlorobenzene and pentachlorobenzene dechlorination were 1,3,5-trichlorobenzene, 1,3- and 1,4-dichlorobenzene, which were formed in a ratio of about 3:2:5. As reported previously, Dehalococcoides sp. strain CBDB1 converted 1,2,3,5-tetrachlorobenzene exclusively to 1,3,5-trichlorobenzene, and 1,2,4,5-tetrachlorobenzene exclusively to 1,2,4-trichlorobenzene. The organism therefore catalyzes two different pathways to dechlorinate highly chlorinated benzenes. In the route leading to 1,3,5-trichlorobenzene, only doubly flanked chlorine substituents were removed, while in the route leading to 1,3-and 1,4-dichlorobenzene via 1,2,4-trichlorobenzene singly flanked chlorine substituents were also removed. Reductive dehalogenase activity measurements using whole cells pregrown with different chlorobenzene congeners as electron acceptors indicated that different reductive dehalogenases might be induced by the different electron acceptors. To our knowledge, this is the first report describing reductive dechlorination of hexachlorobenzene and pentachlorobenzene via dehalorespiration by a pure bacterial culture.