Holliger C, Schraa G, Stams A J, Zehnder A J
Department of Microbiology, Wageningen Agricultural University, The Netherlands.
Appl Environ Microbiol. 1992 May;58(5):1636-44. doi: 10.1128/aem.58.5.1636-1644.1992.
Hexachlorobenzene (HCB), pentachlorobenzene (QCB), all three isomers of tetrachlorobenzene (TeCB), 1,2,3-trichlorobenzene (1,2,3-TCB), and 1,2,4-TCB were reductively dechlorinated by enrichment cultures in the presence of lactate, glucose, ethanol, or isopropanol as the electron donor. The enrichment cultures originated from percolation columns filled with Rhine River sediment in which dechlorination of TCBs and dichlorobenzenes (DCBs) occurred. A stable consortium obtained by transfer on lactate as the energy and carbon source in the presence of 1,2,3-TCB dechlorinated this isomer stoichiometrically to 1,3-DCB. Dechlorinating activity could only be maintained when an electron donor was added. Lactate, ethanol, and hydrogen appeared to be the best substrates. Optimal temperature and pH for dechlorination were 30 degrees C and 7.2, respectively. The specificity of the enrichment on lactate and 1,2,3-TCB was tested after approximately 60 transfers (after 2.5 years). HCB and QCB were stoichiometrically dechlorinated to 1,3,5-TCB and minor amounts of 1,2,4-TCB. 1,3,5-TCB was the sole product formed from 1,2,3,5-TeCB, while 1,2,3,4-TeCB and 1,2,4,5-TeCB were converted to 1,2,4-TCB. 1,2,4-TCB, 1,3,5-TCB, and the three isomers of DCB were not dechlorinated during 4 weeks of incubation. For further enrichment of the 1,2,3-TCB-dechlorinating bacteria, a two-liquid-phase (hexadecane-water) system was used with hydrogen as the electron donor and 1,2,3-TCB or CO2 as the electron acceptor. Methanogens and acetogens were the major substrate-competing (H2-CO2) microorganisms in the two-liquid-phase system. Inhibition of methanogenesis by 2-bromoethanesulfonic acid did not influence dechlorination, and acetogens which were isolated from the enrichment culture did not have dechlorinating activity.(ABSTRACT TRUNCATED AT 250 WORDS)
在以乳酸、葡萄糖、乙醇或异丙醇作为电子供体的情况下，通过富集培养对六氯苯（HCB）、五氯苯（QCB）、四氯苯（TeCB）的所有三种异构体、1,2,3 - 三氯苯（1,2,3 - TCB）和1,2,4 - TCB进行了还原脱氯。这些富集培养物源自填充有莱茵河沉积物的渗滤柱，其中发生了TCBs和二氯苯（DCBs）的脱氯过程。通过在1,2,3 - TCB存在下以乳酸作为能量和碳源进行传代培养，获得了一个稳定的菌群，该菌群将这种异构体化学计量地脱氯为1,3 - DCB。只有添加电子供体时才能维持脱氯活性。乳酸、乙醇和氢气似乎是最佳底物。脱氯的最佳温度和pH分别为30℃和7.2。在大约60次传代（2.5年后）后，测试了对乳酸和1,2,3 - TCB富集的特异性。HCB和QCB被化学计量地脱氯为1,3,5 - TCB和少量的1,2,4 - TCB。1,3,5 - TCB是由1,2,3,5 - TeCB形成的唯一产物，而1,2,3,4 - TeCB和1,2,4,5 - TeCB被转化为1,2,4 - TCB。在4周的培养过程中，1,2,4 - TCB、1,3,5 - TCB和DCB的三种异构体未被脱氯。为了进一步富集1,2,3 - TCB脱氯细菌，使用了双液相（十六烷 - 水）系统，以氢气作为电子供体，1,2,3 - TCB或CO2作为电子受体。产甲烷菌和产乙酸菌是双液相系统中主要的底物竞争（H2 - CO2）微生物。2 - 溴乙烷磺酸对产甲烷作用的抑制并不影响脱氯，并且从富集培养物中分离出的产乙酸菌没有脱氯活性。（摘要截断于250字）
