Equisetum alkaloids degradation in biogas fermentation of E. palustre contaminated plant material

The current expansion of Equisetum palustre in wetlands across the Northern Hemisphere has led to an increase in reports of adverse effects in livestock. In light of the limited reduction potential of toxic Equisetum alkaloids through feed conservation measures, it is essential to identify effective strategies to manage E. palustre infested biomass. This study examined the impact and efficacy of biomethanization processes on the biodegradation of Equisetum alkaloids. To monitor the biodegradation in such complex matrices, a sample preparation method and a high-performance liquid chromatography electrospray ionization mass spectrometry (HPLC-ESI-MS/MS) method were established. The developed method was successfully employed to quantify the total residual content of Equisetum alkaloids in fermentation residues following biomethanization in batch experiments. It was demonstrated that under such conditions a degradation greater than 95 % was achieved. The biomethanization process described here is currently the most effective biological treatment for reducing Equisetum alkaloids. It is notable that the methane yields remained largely unaffected, indicating that field cuttings contaminated with E. palustre can be safely and economically processed via biomethanization which would be a key prerequisite for a circular bioeconomy. [Display omitted] •Equisetum palustre reappears in re-naturalized wetland areas.•Appropriate treatments for the toxic natural Equisetum alkaloids are needed.•A novel analytical method was developed to detect these alkaloids.•Model experiments were conducted to study the fate of these alkaloids in biofermentations.•Biomethanization reduces the level of these alkaloids in contaminated biomass by < 95%.