盐环境下降解菌群对芘的降解特性研究

Degradation characteristics of pyrene by bacteria consortium in saline environment

以芘为多环芳烃(PAHs)的代表物,利用1.0%盐度的无机盐培养基从石油污染土壤中富集出高效嗜盐PAHs降解菌群。通过DNA测序鉴定,菌群中对芘起重要降解作用的是Rhodanobacter、Pseudomonas、Mycobacterium,3者碱基比例达到31.82%。14d内,萘、菲、荧蒽、芘、苯并[a]芘5种PAHs的挥发损耗均可忽略不计。筛选得到的菌群降解芘的最佳条件为:酵母粉质量浓度为120mg/L,盐度不超过1.0%,无需额外添加甲基-β-环糊精。筛选出的降解菌群对芘的最佳降解条件可用于降解萘、菲、荧蒽和苯并[a]芘等其他PAHs,但随着PAHs环数增加,分子量增大,降解率降低。在最佳条件下降解14d时,萘、菲、荧蒽、芘、苯并[a]芘5种PAHs的降解率可分别达100.00%、85.48%、51.92%、56.28%、50.45%。

In this study,the effective polycyclic aromatic hydrocarbons(PAHs)degrading bacteria consortium were enriched from oil-contaminated soil with pyrene as typical PAHs under 1.0%salinity.By DNA sequencing,it was found that the main bacteria consortium which could degrade the PAHs were Rhodanobacter,Pseudomonas and Mycobacterium,taking up 31.82%of base pairs.The volatility of naphthalene,phenanthrene,fluoranthene,pyrene and benzo[a]pyrene could be ignored in 14 d.The degrading bacteria consortium degraded pyrene most effectively when yeast powder mass concentration was 120 mg/L,salinity below 1.0%and without methyl-β-cyclodextrin.The best conditions for pyrene could be applied for naphthalene,phenanthrene,fluoranthene and benzo[a]pyrene.The degradation rates decreased with aromatic rings and molecular weight increased.Under the best conditions,degradation rates of naphthalene,phenanthrene,fluoranthene,pyrene and benzo[a]pyrene were 100.00%,85.48%,51.92%,56.28%and 50.45%,respectively.