全二维气相色谱/飞行时间质谱对微生物降解石油烃产物的分析

Analysis of Microbial Degradation Products of Petroleum Hydrocarbon by Comprehensive Two-Dimensional Gas Chromatography Coupled to Time-of-Flight Mass Spectrometry

采用气相色谱对一株高效石油烃降解菌株微嗜酸寡养单胞菌(Stenotrophomonas acidaminiphila)降解石油烃的产物进行分析,其中80%以上的石油烃被降解,在产物色谱图中,出现了UCM峰,因而,进一步采用全二维气相色谱/飞行时间质谱分析了菌株降解石油烃的产物.结果表明:该菌株能够降解大部分C10-C28正构烷烃、部分直链烷烃和环烷烃,芳香烃尤其是多环芳烃很难被该菌株降解.由检测到中间产物推断:直链烷烃如十六烷,在微生物作用下,生成中间产物十六烷醇,接着被氧化为十六醛和脂肪酸,脂肪酸被进一步氧化,最终生成CO_(2)和H_(2)O;支链烷烃的降解途径和直链烷烃相似,检测到中间产物2-己基-1-十二醇、2-辛基-1-癸醇、2-甲基-1-辛醇等;环烷烃先被氧化为环醇,接着形成环酮,然后被进一步降解,检测到的中间产物有1-环己醇、环辛烷甲醇、3-甲基环戊醇、环庚烷甲醇等;烷基芳香烃被氧化成羧酸,芳香烃苯环羟被基化,随后进行芳环裂解.

Gas chromatography was used to analyze the petroleum hydrocarbon degradation products of a highly efficient petroleum hydrocarbon degrading strain Stenotrophomonas acidaminiphila.More than 80%of petroleum hydrocarbons were degraded.UCM peak appeared in the product chromatogram.The results indicated that the strain was able to degrade most of the C10-C28 n-alkanes,some straight-chain alkanes and cycloalkanes,while the aromatic hydrocarbons,especially polycyclic aromatic hydrocarbons,were difficult to degrade by the strain.According to the intermediate products detected,straight-chain alkanes,such as hexadecane,under the action of microorganisms,generate intermediate products hexadecanol,which was then oxidized to hexadecaldehyde and fatty acids.Fatty acids are further oxidized to finally produce CO_(2) and H_(2)O.The degradation pathway of branched-chain alkanes is similar to that of straight-chain alkanes,and the intermediate products detected were 2-hexyl-1-dodecyl alcohol,2-octyl-1-decanol,2-methyl-1-octanol,etc.Cycloalkanes were first oxidized to cycloalcohols,then to form cycloketones,and then further degraded.The detected intermediate products included 1-cyclohexanol,cyclooctane methanol,3-methylcyclopentanol,cycloheptane methanol,etc.Alkyl aromatics were oxidized to carboxylic acids,and the phenyl ring of the aromatics was hydroxylated,followed by aromatic ring cracking.