Quantitative analysis of tetrahydrofolate metabolites from <italic>clostridium autoethanogenum</italic>.

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 acetyl-CoA, 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. [ABSTRACT FROM AUTHOR]