Asphaltenic compounds in heavy oils may be biologically functionalized in the contexts of oil upgrading and in mitigating contamination however there are knowledge gaps in regard to the mechanisms of asphaltene functionalization by microorganisms. Due to the challenges of studying asphaltene functionalization, model asphaltene compounds comprised of polyaromatic centers and long alkyl chains may be utilized. In this work, a soil bacterium identified as Pseudomonas aeruginosa KK6 was characterized and it was found to extensively biotransform the water insoluble polycyclic n-alkylaromatic model asphaltene, 1-dodecylnaphthalene (1-DDN). Gas chromatography was utilized to quantify 1-DDN transformation and liquid chromatography with UV detection coupled to electrospray ionization tandem mass spectrometry (LC-UV/ESI-MS/MS) was used to analyze transformation products. An unusual transformation product profile occurred that showed that varying alkyl chain length compounds that differed by one methylene unit each were detected attached to their polycyclic aromatic chromophores. CID product ion scan analyses revealed that 1-DDN was transformed into oxidized, alkyl chain-shortened, reduced molecular weight 1-naphthyl-alkanoic acids and 1-naphthyl-alkanals and results interpretation supported that these compounds were produced through subterminal oxidation mechanisms by strain KK6. Based upon the results, biotransformation pathways that described the biological functionalization of a model asphaltene compound were constructed. On its own or in conjunction with polycyclic aromatic hydrocarbon-degrading bacteria, this strain may be applied to upgrading heavy oil.

在油提质和减轻污染的背景下，重油中的沥青质化合物可以进行生物功能化，但是在微生物对沥青质功能化的机理方面存在知识空白。由于研究沥青质官能化的挑战，可以使用由聚芳族中心和长烷基链组成的模型沥青质化合物。在这项工作中，鉴定了一种被鉴定为铜绿假单胞菌KK6的土壤细菌，发现该细菌广泛地生物转化了水不溶性多环N-烷基芳族模型沥青质，1-十二烷基萘（1-DDN）。气相色谱法用于定量1-DDN转化，液相色谱法通过紫外检测与电喷雾电离串联质谱法（LC-UV / ESI-MS / MS）结合使用，以分析转化产物。发生了异常的转化产物图谱，该图谱表明检测到的烷基链长度不同的化合物（每个相差一个亚甲基单元）附着在其多环芳族发色团上。CID产物离子扫描分析表明，1-DDN转化为氧化的，烷基链缩短的，降低了分子量的1-萘基链烷酸和1-萘基链烷醛，结果表明，这些化合物是通过菌株的亚末端氧化机理生产的KK6。根据结果​​，构建了描述模型沥青质化合物生物功能化的生物转化途径。单独或与多环芳烃降解细菌结合使用，此菌株可用于重油提质。