Department of Soil and Environmental Sciences, University of California, Riverside, California 92521.
Appl Environ Microbiol. 1985 Oct;50(4):1058-63. doi: 10.1128/aem.50.4.1058-1063.1985.
The metabolism of C-labeled PCBs (polychlorinated biphenyls), which comprised the Aroclor 1242 mixture, was greatly enhanced by the addition of biphenyl (BP) to soil. After 49 days, only 25 to 35% of the original PCBs remained in the soil, and 48 to 49% was converted to CO(2) (including soil carbonates) in treatments enriched with BP; by contrast, 92% of the PCBs remained and less than 2% was converted to CO(2) in the unenriched control. Although the mineralization of PCBs in soils inoculated with Acinetobacter strain P6 was not greater than that in uninoculated BP-enriched soils, the initial and maximum mineralization rates and the disappearance of more highly chlorinated PCBs were greater with Acinetobacter strain P6. The mineralization of BP was consistent with kinetic models based upon linear-no growth and exponential growth; lower cell densities (<10/g) of BP-oxidizing bacteria gave a better fit for exponential growth, whereas the highest cell density (10/g) gave a better fit for linear-no growth. The numbers of BP-oxidizing bacteria declined exponentially upon depletion of the substrate. Since the mineralization of the chlorinated cometabolites was brought about by microorganisms (commensals) other than BP oxidizers, CO(2) production could not be fit to either of the two growth models. However, CO(2) production from the highest-density inoculum could be fit to a first-order (no-growth) sequential-reaction series. Although the population dynamics of the commensals could not be determined, the rate-limiting step in the cometabolic-commensal metabolism of PCBs to CO(2) had to be the initial oxidation, since the rate of CO(2) production was directly related to the population density of BP oxidizers.
多氯联苯（PCBs）的 C 标记物（由 Aroclor 1242 混合物组成）的代谢在加入联苯（BP）到土壤中后大大增强。49 天后，只有 25%到 35%的原始 PCB 留在土壤中，而在富含 BP 的处理中，48%到 49%转化为 CO（2）（包括土壤碳酸盐）；相比之下，92%的 PCB 留在未富集的对照土壤中，不到 2%转化为 CO（2）。虽然接种不动杆菌 P6 的土壤中 PCB 的矿化作用并不大于未接种 BP 富集土壤中的矿化作用，但不动杆菌 P6 的初始和最大矿化率以及更高氯化度 PCB 的消失率更高。BP 的矿化作用与基于线性无生长和指数生长的动力学模型一致；较低的 BP 氧化菌细胞密度（<10/g）更适合指数生长，而最高细胞密度（10/g）更适合线性无生长。随着基质的耗尽，BP 氧化菌的数量呈指数下降。由于氯化共代谢物的矿化是由微生物（共生菌）而不是 BP 氧化剂引起的，因此 CO（2）的产生不能符合这两种生长模型中的任何一种。然而，来自最高密度接种物的 CO（2）产生可以拟合一级（无生长）顺序反应系列。虽然无法确定共生菌的种群动态，但 PCB 与 CO（2）的共代谢-共生代谢的限速步骤必须是初始氧化，因为 CO（2）产生的速率与 BP 氧化剂的种群密度直接相关。
