Ethene

PCE, cDCE (both ≥99.5%), VC (≥99.5%), ethene (≥99.9%), Vitamin B₁₂ (≥98%), sodium fumarate (≥98%), and N₂O (≥99%) were purchased from Sigma-Aldrich (St Louis, MO, USA). All other chemicals used in this study were reagent grade or of higher purity.

Vitamin B₁₂ (≥98%), dicyanocobinamide (Cbi, ≥93%), 5,6-dimethylbenzimidazole (DMB) (99%), 5-methylbenzimidazole (5-MeBza) (98%), 5-methoxybenzimidazole (5-OMeBza) (97%), benzimidazole (Bza) (98%), purine (98%) were purchased from Sigma-Aldrich. ¹⁵NH₄Cl (99%) was obtained from Cambridge Isotope Laboratories. Yeast extract and peptone were purchased from Becton, Dickinson and Company. Bza-Cba, 5-MeBza-Cba and 5-OMeBza-Cba were prepared via guided cobamide biosynthesis ^{10 (link)}. Factor III (5-OHBza-Cba), norpseudo vitamin B₁₂ and phenolic cobamides (i.e., Phenol-Cba and p-Cresol-Cba) were extracted and purified from Methanosarcina barkeri strain Fusaro (DSM 804), Sulfurospirillum multivorans (DSM 12446) and Sporomusa sp. strain KB-1 (16S rRNA gene GenBank accession no. AY780559.1) cells, respectively. Concentrations of purified cobamides were determined at 361 nm with a Lambda 35 UV-Vis spectrometer (PerkinElmer) using a molar extinction coefficient of 28,060 mole⁻¹ cm^{−1 12 (link)}. Ethene (≥99.9%) and vinyl chloride (≥99.5%) were purchased from Sigma-Aldrich. All other chemicals used were reagent grade or higher.