Abstract Biodegradation of the more resistant hopanoids was examined using residual stains in a Paleogene paleomigration conduit on the Utsira High, Norwegian North Sea, together with related less degraded oils. Under currently anoxic conditions, the most severely biodegraded samples contain 25-nor, 28-nor and 25,28-dinorhopanes, in addition to regular hopanes, neohopanes, diahopanes and didiahopanes [9,15-dimethyl-25,27-dinorhopanes]. The C27 member of the 25,28-dinorhopanes comprises closely eluting 17α,21β and 17β,21α isomers. A pair of C31 compounds eluting just after the 17α-homohopanes were tentatively identified as the 22S/R isomers of homo-18α-neohopane. The 28,30-dinorhopane peak seems to comprise 17α,21β and 17β,21α isomers, with relatively more of the less thermodynamically stable 17α,21β contributing under the most severe biodegradation. The approximate order of increasing susceptibility to biodegradation was: gammacerane ≈ triaromatic 23,24-dimethylcholesteroids ≈ triaromatic dinosteroids

中文翻译：

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降霍烷的生物降解生产和破坏——以挪威北海 Utsira High 古近系古迁移管道中的残油为例

摘要 使用挪威北海 Utsira High 的古近纪古迁移管道中的残留污渍以及相关的降解程度较低的油类，研究了抗性更强的藿烷类化合物的生物降解情况。在目前的缺氧条件下，最严重的生物降解样品除了常规的hopanes、nehopanes、diahopanes 和didiahopanes [9,15-dimethyl-25,27-dinorhopanes] 之外，还含有25-nor、28-nor 和25,28-dinorhopanes。25,28-dinorhopanes 的 C27 成员包含紧密洗脱的 17α,21β 和 17β,21α 异构体。一对 C31 化合物刚好在 17α-高藿烷被初步鉴定为 18α-新hopane 的 22S/R 异构体后洗脱。28,30-二萘醌峰似乎包含 17α,21β 和 17β,21α 异构体，相对较多的热力学稳定性较差的 17α，21β 在最严重的生物降解作用下起作用。对生物降解的敏感性增加的大致顺序是：γcerane ≈ 三芳族 23,24-二甲基胆甾醇 ≈ 三芳族 Dinosteroids