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.
Keywords: Acetogens; Gas fermentation; Metabolome; Tetrahydrofolates; Wood–Ljungdahl pathway.