Untargeted Metabolite Profiling for Screening Bioactive Compounds in Digestate of Manure under Anaerobic Digestion

Abstract

Untargeted metabolite profiling was performed on chicken manure (CHM), swine manure (SM), cattle manure (CM), and their respective digestate by XCMS coupled with MetaboAnalyst programs. Through global chemical profiling, the chemical characteristics of different digestates and types of manure were displayed during the anaerobic digestion (AD) process. As the feed for AD, CM had less easily-degradable organics, SM contained the least O-alkyls and anomerics of carbohydrates, and CHM exhibited relatively lower bio-stability. The derived metabolite pathways of different manure during the AD process were identified by MetaboAnalyst. Twelve, 8, and 5 metabolic pathways were affected by the AD process in CHM, SM, and CM, respectively. Furthermore, bioactive compounds of digestate were detected, such as amino acids (L-arginine, L-ornithine, L-cysteine, and L-aspartate), hormones (L-adrenaline, 19-hydroxy androstenedione, and estrone), alkaloids (tryptamine and N-methyltyramine), and vitamin B5, in different types of manure and their digestates. The combination of XCMS and MetaboAnalyst programs can be an effective strategy for metabolite profiling of manure and its anaerobic digestate under different situations.