混合菌降解土壤中多环芳烃的试验研究

PAHs Biodegradation in Soil by Inoculation of Isolated Microorganisms

PAHs生物降解程度受多种因素影响。通过筛选驯化PAHs降解菌,研究混合菌对土壤中菲、芘、苯并(a)蒽、苯并(b)荧蒽、苯并(k)荧蒽、茚并(1,2,3-cd)芘的生物降解性能,并考察污染时间对土壤中PAHs降解效果的影响。结果表明,筛选的混合菌具有很强的PAHs降解能力,缩短了PAHs生物降解的半衰期,且PAHs起始降解速率较快,之后趋于平缓。27d内土壤中的菲、芘、苯并(a)蒽、苯并(b)荧蒽、苯并(k)荧蒽、茚并(1,2,3-cd)芘的平均降解率分别为98.14%、89.97%、88.47%、63.55%、65.24%、60.49%,其中菲在5d之内的降解率高于93%。污染210d的土壤中各PAHs的起始降解速率高于污染50d的土壤,因此污染时间越长,PAHs生物降解的停滞期越短。

The rate and extent of polycyclic aromatic hydrocarbons（PAHs）biodegradation in soil are affected by various factors,mainly including contact toxicity,soil-PAHs contact time,microbial population and environmental parameters.In this paper,the biodegradation efficiency of PAHs mixtures（consisting of phenanthrene,pyrene,benz（a）anthracene,benzo（b）fluoranthene,benzo（k）fluoranthene and indeno（1,2,3-cd）pyrene）with the inoculation of mixed microbial consortia was studied.The mixed microbial consortia were isolated from PAHs contaminated soil,mainly including Sphingomonas,Methylobacterium,Burkholderia,Rhodobacterium,Bradyrhizobium,Phyllobacterium,Chryseobacterium and Microbacterium.The results indicated that the isolated mixed microbial consortia were capable of mineralizing PAHs,and the half life of phenanthrene,pyrene,benz（a）anthracene,benzo（b）fluoranthene,benzo（k）fluoranthene and indeno（1,2,3-cd）pyrene in soil was 6.12,8.25,8.74,19.31,20.06 and 22.28 days,respectively.The initial biodegradation rates of these PAHs were faster at the beginning states,then became slower after the incubation of 17 days.The average biodegradation efficiency of phenanthrene,pyrene,benz（a）anthracene,benzo（b）fluoranthene,benzo（k）fluoranthene and indeno（1,2,3-cd）pyrene after 27 days was 98.14%,89.97%,88.47%,63.55%,65.24% and 60.49%,respectively.More than 93% of phenanthrene was degraded within the incubation of 5 days.The initial biodegradation rate of pyrene,benz（a）anthracene,benzo（b）fluoranthene,benzo（k）fluoranthene and indeno（1,2,3-cd）pyrene in soil contaminated for 210 days was 0.847 5,0.898 5,0.302 8,0.197 6 and 0.137 8 mg·kg-1·d-1,respectively.However,the initial biodegradation rate of these PAHs in soil contaminated for 50 days was 0.451 6,0.662 8,0.196 4,0.165 3 and 0.093 6 mg·kg-1·d-1,respectively.The lag phase of degradation was shorter with increasing soil-PAHs contact time.