石油污染对土壤微生物群落影响及石油降解菌的筛选鉴定

为研究石油污染对土壤中细菌群落结构及土壤理化性质的影响,分离筛选石油降解菌,从陕北宝塔、吴起、靖边和延长4个县区采集石油污染土壤和未受石油污染土壤,测量土壤中石油、有机质、硝态氮、铵态氮、速效磷、速效钾的含量以及pH;采用高通量测序技术对2种土壤中细菌群落结构进行比较分析;并以石油为唯一碳源,从石油污染土壤中筛选高效石油降解菌,并对所筛选的高效石油降解菌进行16S rDNA鉴定。陕北4个县区石油污染土壤中铵态氮、硝态氮、速效磷和速效钾含量分别降低了0.57,6.63,4.34,8.91 mg/kg,有机质含量增加了2~21倍。石油污染土壤中细菌群落的丰富度和多样性均降低,其中变形菌门(Proteobacteria)和绿弯菌门(Chloroflexi)为主要菌门,分枝杆菌属(Mycobacterium)为丰度最高菌属。以石油为唯一碳源,分离得到8株石油降解菌,其中菌株OS33和菌株OS62-1在5 d内的石油降解率分别为80.51%和81.60%,经鉴定OS33为迪茨氏菌(Dietzia sp.),OS62-1为红球菌(Rhodococcus sp.)。石油污染发生后,土壤中细菌群落的丰富度和多样性降低,筛选的8株石油降解菌中OS62-1石油降解率最高,研究结果进一步丰富了陕北地区石油降解菌菌种资源库。

INFLUENCE OF PETROLEUM CONTAMINATION ON SOIL MICROBIAL COMMUNITY AND ISOLATION AND IDENTIFICATION OF OIL-DEGRADING BACTERIA

This research intended to investigate the influence of oil contamination on bacterial community,soil physico-chemical properties,and to isolate and identify oil-degrading bacteria.In this work,the microbial community structure of oil-contaminated soil and control soil in Baota,Wuqi,Jingbian,and Yanchang counties in northern Shaanxi were analyzed based on high-throughput sequencing technology,and the oil content,organic matter,nitrate nitrogen,ammonium nitrogen,available phosphorus,available potassium and pH were measured.With petroleum as the sole carbon source,oil-degrading bacteria were screened from oil-contaminated soils and identified based on 16S rDNA gene sequence.The contents of ammonium nitrogen,nitrate nitrogen,available phosphorus,and available potassium decreased by 0.57,6.63,4.34,8.91 mg/kg,respectively,and the content organic matter increased by 2~21 times.The richness and diversity of microorganisms were reduced after being contaminated with crude oil.In the oil-contaminated soil,Proteobacteria and Chloroflexi were the dominant phylum,and Mycobacterium was the genus with the highest abundance.Using petroleum as the only carbon source,8 strains of oil-degrading bacteria were isolated,among them,the 5-day oil degradation rates of OS33 and OS62-1 strains reached 80.51% and 81.60%.Finally,OS33 was identified as Dietzia sp.,and OS62-1 was Rhodococcus sp.After being contaminated with crude oil,the soil microbial community richness and diversity were decreased.8 oil-degrading bacteria were isolated and the highest 5-day oil degradation rate was 81.60%.This study further enriched the oil-degrading bacteria resource of northern Shaanxi.