湖泊湿地石油烃降解菌筛选与原油动-静态降解研究

Screening of Crude-Oil Degrading Bacteria from a LakeWetland and the Dynamic-Static Degradation

筛选石油烃高效降解菌有利于石油污染湖泊湿地的原位修复。本文以原油为唯一碳源,从安庆湿地的石油烃污染水体中筛选出了一株原油高效降解菌,经形态学和16S rRNA测序鉴定为芽孢杆菌(命名为Bacillus sp.L1)。并利用气相色谱-质谱联用仪(GC-MS)分析了该菌在实验室动态(37°C,180 r/min)和静态(37℃,0 r/min)培养3个月的原油降解效果。原油动-静态降解结果发现该菌株在动态下对nC_(13)~nC_(35)(M/Z=85)的降解率在86%~100%之间;静态下nC_(13)~nC_(19)的降解率在95%~100%,但nC20~nC35的降解率在69%~97%之间,整体呈现随着分子量变大降解效率下降的趋势。与此同时,该菌在动-静态下均可以有效降解原油中烷基环己烷(M/Z=82)、烷基苯(M/Z=92)和烷基甲苯(M/Z=106)等组分,而且,对原油中大部分芳香族化合物也具有一定程度的降解,同时芳香族同系物家族内部各分子降解难易程度也存在差异。Bacillus sp.L1在动-静态降解条件下对石油主要组分均表现出良好的降解潜能,并在一定程度上动态降解效果优于静态降解,这在自然湿地石油类污染的生物修复领域具有良好的应用前景。

Screening bacteria of degrading crude oil efficiently will benefit in-situ remediation of oil-polluted lake wetlands.In this paper,one strain was isolated from the oil-polluted lake wetland in Anqing by using crude oil as the sole carbon,named Bacillus sp.L1 according to the typical morphological characterization and 16S rRNA sequencing.Gas chromatography-mass spectrometry(GC-MS)was carried out to detect crude-oil degradation conditions under the dynamic cultivation(37℃,180 r/min)and static cultivation(37℃,0 r/min)during 3 months in the laboratory.It found that the degradation rate of nC_(13)~nC_(35)(M/Z=85)in crude oil ranged from 86%to 100%under the dynamic cultivation.Besides,the rate of nC_(13)~nC_(19)ranged from 95%to 100%under the static cultivation,as well as a lower rate range from 69%to 97%for nC_(20)~nC_(35),showing a decrease tendency of the degrading ability with the increasing of molecular weight on the whole.Additionally,the strain could fully utilize crude oil compositions of alkylcyclohexane(M/Z=82),alkylbenzene(M/Z=92)and alkyltoluene(M/Z=106)under both cultivation conditions.Furthermore,Bacillus sp.L1 has a capability of degrading most aromatic compounds in crude oil to a certain extent,emerging different degradation ability of various compounds within the family of aromatic homologues.Our study revealed that Bacillus sp.L1 has a good degradation potential of crude oil compositions under the dynamic-static cultivation,and the degrading effect under dynamic cultivation is generally better than the static.This finding should be very helpful for the bioremediation of crude-oil polluted natural wetlands.