AEROBIC DEGRADATION OF POLYCHLORINATED BIPHENYLS

多氯联苯（PCBs）被广泛使用， 现在被认为是最有问题的污染物之一。 最 有前途的方法，生物修复的多氯联苯是一个组合 厌氧-好氧工艺 厌氧降解导致 高氯化多氯联苯的脱氯和低氯化多氯联苯的累积 氯化同系物。 八种同系物，包括2-，4-，2，4-，2，6-， 2-2- ，2-4- ，2，4 -2- ，和2，4 -4- 氯联苯（CB）包含70 Aroclor 1242的厌氧脱氯产物的85%。 虽然许多好氧细菌已经筛选出的光谱， 它们可以降解的多氯联苯，关于降解和 在厌氧过程中积累的同源物形成的最终产品 脱氯工艺。 为此选择了四种细菌菌株 基于其优异的PCB降解能力， 质量 采用光谱法分析主要的特异性 多氯联苯的攻击和最终产品形成的好氧细菌。 基于 质谱、紫外光谱和HPLC数据菌株 Rhodococcus sp. RHA 1和Burkholderia sp. LB 400的结论是， 优先攻击邻氯环，而另外两个 菌株（睾丸酮Commamonas testosteroni VP 44和红球菌属NY 05） 优先氧化对位取代的环。 结果表明 邻位集中的菌株表现出更有效的多氯联苯降解 厌氧脱氯产物。 众所周知，有氧运动 多氯联苯的降解通常涉及部分降解， 在氯苯甲酸盐的生产中。 我们还发现了氯苯甲酸盐 作为某些同系物降解的主要产物。 然而，在这方面， 降解2-4 和2，4 -4-CB通过副聚焦细菌导致 这些同系物的不完全转化和 这些氯联苯的间位裂解产物作为死胡同 代谢物。 这些化合物是根据质量 光谱数据（GC-MS）。

Polychlorinated biphenyls (PCBs) were widely used and are considered now as one of the most problematic pollutants. The most promising approach for bioremediation of PCBs is a combined anaerobic-aerobic process. Anaerobic degradation results in reductive dechlorination of highly chlorinated PCBs and accumulation of less chlorinated congeners. Eight congeners including 2-, 4-, 2,4-, 2,6-, 2-2-, 2-4-, 2,4-2-, and 2,4-4-chlorobiphenyl (CB) comprise from 70 to 85% of anaerobic dechlorination products from Aroclor 1242. Although many aerobic bacteria have been screened for the spectra of PCBs which they can degrade, little is known about degradation and final products formed from congeners that accumulate during anaerobic dechlorination processes. Four bacterial strains were chosen for this investigation based on their superb PCB degradative abilities. Mass spectrometry was employed to analyze the specificity of the primary PCBs attack and the final products formed by aerobic bacteria. Based on mass spectrometry, UV-spectroscopy and HPLC data strains Rhodococcus sp. RHA1 and Burkholderia sp. LB400 were concluded to preferentially attack on ortho-chlorinated rings, while another two strains (Commamonas testosteroni VP44 and Rhodococcus sp. NY05) preferentially oxidized a para-substituted rings. It was shown that the ortho-focused strains showed more efficient degradation of Aroclor anaerobic dechlorination products. It is known that aerobic degradation of PCBs usually involves partial degradation and results in the production of chlorobenzoates. We also found chlorobenzoates as the major products of degradation of selected congeners. However, degradation of 2-4 and 2,4-4-CB by para-focused bacteria resulted in incomplete transformation of these congeners and accumulation of meta-cleavage products of these chlorobiphenyls as a dead end metabolites. These compounds were identified based on mass spectrometric data (GC-MS).