一株副球菌对污染土壤中多环芳烃的降解研究

Biodegradation of PAHs by Paracoccus aminovorans HPD-2 in Contaminated Soil

从受多环芳烃(PAHs)长期污染的土壤中分离到一株降解PAHs的噬氨副球菌(Paracoccus aminovorans)HPD-2。使用HPD-2的菌液对PAHs污染的土壤进行了2周的生物降解试验,结果表明加入HPD-2能够明显提高土壤中PAHs的降解率。加菌土壤中PAHs的总去除率为22.9%,PAHs各组分的降解率在19.5%～36.2%之间。其中三环PAHs的降解率最高(36.1%),五环次之(26.0%),四环的最低(20.9%)。对土壤微生物的计数结果发现,HPD-2的加入显著提高了土壤中细菌的数量,而对放线菌和真菌的影响不明显。PCR-DGGE分析结果表明,降解过程中HPD-2可能成为土壤中的优势菌。以上结果表明该菌株在PAHs污染土壤的生物降解中具有较好的应用前景。

The effects of the inoculant strain Paracoccus aminovorans HPD-2 （isolated from a PAH-contaminated soil） on the bioremediation of the PAHs-contaminated soil and the structure of microbial communities in the soil were studied in soil microcosms. After inoculation for 14 days, 22.9% of total PAHs were removed from the soil in the treatment with the addition of 20% （v/m） bacterium suspension. The removal of 3-rings PAHs （36.1%） was higher than that of 5-rings （26.0%） and 4-rings PAHs （20.9%）. The highest degradation of PAHs occurred in phenanthrene, anthracene, and benzo[a]pyrene. Bacterial population in the soil increased during the bioremediation process, but the population of actinomycetes and fungi changed insignificantly. Denaturing gradient gel electrophoresis （DGGE） analysis of polymerase chain reaction （PCR）-amplified bacterial 16S rRNA gene fragments revealed that HPD-2 became into the dominant bacterial group in the soil with the addition of the bacterium suspension. These results indicate that HPD-2 is a promising candidate for bioremediation of PAHs-contaminated soils.