Population dynamics of polychlorinated biphenyl-dechlorinating microorganisms in contaminated sediments
Population dynamics of polychlorinated biphenyl-dechlorinating microorganisms in contaminated sediments
复制标题
污染沉积物中多氯联苯脱氯微生物的种群动态
DOI：
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发表时间：
1997
影响因子：
4.4
通讯作者：
G. Rhee
中科院分区：
文献类型：
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作者：
J. Kim;G. Rhee
采用最可能数法首次测定了多氯联苯（PCB）脱氯微生物的生长动态，以及硫酸盐还原剂和产甲烷菌的生长动态。Aroclor 1248脱氯的时间进程反映了脱氯器的生长；当脱氯群体从2.5 × 10（sup5）增加到4.6 × 10（sup7）细胞g沉淀物（sup1）时，以2至6周的6.7天（sup1）的特定生长速率增加2个数量级，随后进行脱氯。在此期间，多氯联苯脱氯微生物以3.9 × 10(sup-8) mol Cl g （sup-1）天（sup-1）的速率（sup-1）对Aroclor 1248进行脱氯，使每个联苯的平均Cl分子数从3.9减少到2.8。脱氯氯（sup1）的生长量为4.2 × 10（sup13）细胞mol。一旦脱氯达到平稳期，6周后，脱氯器的数量开始减少。另一方面，接种到不含多氯联苯的沉积物中的除氯剂随着时间的推移而减少，这表明多氯联苯是它们选择性富集所必需的。无多氯联苯和污染沉积物中硫酸盐还原剂和产甲烷菌数量均有所增加，但差异不大。硫酸盐还原菌的最大种群大小比除氯菌大一个数量级，而产甲烷菌的最大种群大小略小。然而，与脱氯剂不同的是，即使在脱氯停止后，硫酸盐还原剂和产甲烷菌的数量仍然很高。本研究的结果表明，PCB浓度可能必须超过一定的阈值才能维持PCB脱氯器的生长。
The growth dynamics of polychlorinated biphenyl (PCB)-dechlorinating microorganisms were determined for the first time, along with those of sulfate reducers and methanogens, by using the most-probable-number technique. The time course of Aroclor 1248 dechlorination mirrored the growth of dechlorinators; dechlorination ensued when the dechlorinating population increased by 2 orders of magnitude from 2.5 x 10(sup5) to 4.6 x 10(sup7) cells g of sediment(sup-1), at a specific growth rate of 6.7 day(sup-1) between 2 and 6 weeks. During this period, PCB-dechlorinating microorganisms dechlorinated Aroclor 1248 at a rate of 3.9 x 10(sup-8) mol of Cl g of sediment(sup-1) day(sup-1), reducing the average number of Cl molecules per biphenyl from 3.9 to 2.8. The growth yield was 4.2 x 10(sup13) cells mol of Cl dechlorinated(sup-1). Once dechlorination reached a plateau, after 6 weeks, the number of dechlorinators began to decrease. On the other hand, dechlorinators inoculated into PCB-free sediments decreased over time from their initial level, suggesting that PCBs are required for their selective enrichment. The numbers of sulfate reducers and methanogens increased in both PCB-free and contaminated sediments, showing little difference between them. The maximum population size of sulfate reducers was about an order of magnitude higher than that of dechlorinators, whereas that of methanogens was slightly less. Unlike those of dechlorinators, however, numbers of both sulfate reducers and methanogens remained high even when dechlorination ceased. The results of this study imply that PCB concentrations may have to exceed a certain threshold to maintain the growth of PCB dechlorinators.