Cross-feeding in Anaerobic Digestion Ecosystems

Metabolic cross-feeding is an interaction between microbial communities, where a compound produced by the metabolism of one microorganism is utilized by another. There are two types of microbial cross-feeding within anaerobic digestion ecosystems: cascade and reciprocal. Cascade cross-feeding is unidirectional, typically involving catabolic processes and byproducts such as organic acids. In contrast, reciprocal cross-feeding is bidirectional or multidirectional, usually involving anabolic processes and cooperative interactions, exchanging metabolites like amino acids. Cross-feeding interactions based on amino acids and vitamins are common in microbial communities. The adoption of cross-feeding in anaerobic digestion can advance the mechanistic understanding of anaerobic digestion processes, improve better exploration of metabolic pathways, and enhance system efficiency for better-recovering resources.