This study aimed to investigate the effects of cofD gene knock-out on the synthesis of coenzyme F₄₂₀ and production of methane in Methanobrevibacter ruminantium (M. ruminantium). The experiment successfully constructed a cofD gene knock-out M. ruminantium via homologous recombination technology. The results showed that the logarithmic phase of mutant M. ruminantium (12 h) was lower than the wild-type (24 h). The maximum biomass and specific growth rate of mutant M. ruminantium were significantly lower (P < 0.05) than those of wild-type, and the maximum biomass of mutant M. ruminantium was approximately half of the wild-type; meanwhile, the proliferation was reduced. The synthesis amount of coenzyme F₄₂₀ of M. ruminantium was significantly decreased (P < 0.05) after the cofD gene knock-out. Moreover, the maximum amount of H₂ consumed and CH₄ produced by mutant were 14 and 2% of wild-type M. ruminantium respectively. In conclusion, cofD gene knock-out induced the decreased growth rate and reproductive ability of M. ruminantium. Subsequently, the synthesis of coenzyme F₄₂₀ was decreased. Ultimately, the production capacity of CH₄ in M. ruminantium was reduced. Our research provides evidence that cofD gene plays an indispensable role in the regulation of coenzyme F₄₂₀ synthesis and CH₄ production in M. ruminantium.

本研究旨在探讨cofD基因敲除对反刍甲烷短杆菌( M. ruminantium )合成辅酶F ₄₂₀和产甲烷的影响。实验通过同源重组技术成功构建了cofD基因敲除的反刍分枝杆菌。结果表明，突变体反刍分枝杆菌的对数生长期（12 h）低于野生型（24 h）。突变体反刍分枝杆菌最大生物量和比生长率均显着低于野生型（ P < 0.05），且突变体反刍分枝杆菌最大生物量约为野生型的一半；与此同时，扩散减少了。 cofD基因敲除后反刍分枝杆菌辅酶F ₄₂₀合成量显着降低( P < 0.05)。此外，突变体最大消耗的H ₂量和最大产生的CH ₄量分别是野生型反刍分枝杆菌的14％和2％。总之， cofD基因敲除导致反刍动物生长速度和繁殖能力下降。随后，辅酶F ₄₂₀的合成减少。最终，反刍分枝杆菌中CH ₄的生产能力降低。我们的研究证明cofD基因在反刍动物辅酶F ₄₂₀合成和CH ₄产生的调控中发挥着不可或缺的作用。