Quantitative analysis of tetrahydrofolate metabolites from clostridium autoethanogenum

Introduction Quantification of tetrahydrofolates (THFs), important metabolites in the Wood-Ljungdahl pathway (WLP) of acetogens, is challenging given their sensitivity to oxygen. Objective To develop a simple anaerobic protocol to enable reliable THFs quantification from bioreactors. Methods Anaerobic cultures were mixed with anaerobic acetonitrile for extraction. Targeted LC-MS/MS was used for quantification. Results Tetrahydrofolates can only be quantified if sampled anaerobically. THF levels showed a strong correlation to acetylCoA, the end product of the WLP. Conclusion Our method is useful for relative quantification of THFs across different growth conditions. Absolute quantification of THFs requires the use of labelled standards.