Control of anaerobic organo-chlorinated compound degrading mixed culture under restricted hydrogen condition and its application for bioremediation

本研究的目的是构建降解氯乙烯的混合菌种，测定不同氢气浓度下的降解特性及其在生物修复中的应用。构建了一株氯乙烯降解富集菌，并对其降解特性进行了研究。该高浓缩培养物的菌源为荷田土壤。在21天内，10 mg/l的顺式二氯乙烯经浓缩培养即可完全降解为乙烯。添加5%的荷花土可保持较高的降解活性。脱卤球菌数维持在10~7拷贝/ml，在有机酸中，尤其是乳酸对顺式-DCE的降解活性有显著的促进作用。VBI的加入提高了降解率。较低的ORP和中性pH也是获得高降解活性的重要因素。氢气浓度是保持较高脱氯率的重要因素。在氢气浓度小于10^4 ppmv revel的条件下，顺式-DCE被降解为氯乙烯，而VC被降解为乙烯。为了保持较高的氯乙烯降解率，控制低氢、低有机酸和高VB12浓度是非常重要的因素。

The purpose of this research is to construct chloroethene degrading mixed culture and to determine the degradation characteristics at various hydrogen concentrations and its application for bioremediation. A chloroethene degrading enrichment culture was constructed and its biodegradation characteristics were investigated. The bacterial source of the highly enriched culture was a lotus field soil. cis-DCE of 10mg/1 was completely degraded to ethene in 21 days by the enrichment culture. The high degradation activity was kept by the addition of 5% of the lotus field soil. The number of Dehalococcoides was kept at 10^<6-7> copies/ml. In organic acids, especially lactate significantly accelerated the cis-DCE degradation activity. The degradation rate increased by the addition of VBI.2. The low ORP and neutral pH were also important factors to achieve the high degradation activity. The hydrogen concentration was a very important factor to keep high dechlorination rate. cis-DCE was degraded to vinyl chloride at the hydrogen concentration less than10^4ppmv revel and VC was degraded to ethylene less than 10^3ppmv revel. In order to keep the high degradation rate of contaminating chloroethene, to control the low hydrogen, the low organic acid and the high VB^<12> concentrations were very important factors.