Metabolic Sequences of Anaerobic Fermentation on Glucose-Based Feeding Substrates Based on Correlation Analyses of Microbial and Metabolite Profiling

Abstract

Degradation processes in various biomasses are managed by complex metabolic dynamics created by diverse and extensive interactions and competition in microbial communities and their environments. It is important to develop visualization methods to provide a bird's-eye view when characterizing the entire sequential metabolic process in an environmental ecosystem. Here, we describe an approach for the visualization of the metabolic sequences in anaerobic fermentation ecosystems, characterizing the entire metabolic dynamics using a combination of microbial community profiles and metabolic profiles. By evaluating their time-dependent variation, we found that microbial community profiles and metabolite production processes were characteristically affected by the feeding of different glucose-based substrates (glucose, starch, cellulose), although the compositions of the major microbial community and the metabolites detected were likely to be similar in all experiments. This combinatorial approach to variation in microbial communities and metabolic profiles was used successfully to visualize metabolic sequences in anaerobic fermentation ecosystems, in addition to mining candidate microbiota for cellulose degradation. Thus, this approach provides a powerful tool for visualizing and evaluating metabolic sequences within the biomass degradation process in an environmental ecosystem. This is the first report to visualize the entire metabolic dynamic in an anaerobic fermentation ecosystem as metabolic sequences.