Metagenomic insights into protein degradation mechanisms in natural fermentation of cassava leaves

Cassava (Manihot esculenta Crantz) leaves, the primary by-product of cassava processing, constitute a significant protein source, accounting for 18 to 38 percent on a dry weight basis. Despite their nutritional value, a substantial portion of these leaves is often discarded post-harvest, resulting in notable resource waste. This study employs metagenomic technology to investigate the protein degradation mechanism in cassava leaves, aiming to provide a technical reference for value-added of this by-product. Following a 36-hour period of natural fermentation, the protein degradation rate reached 58%, a phenomenon intricately linked to both the microbial community structure and its functional properties. Notably, Lactococcus and Enterobacter, recognized for their abundant protease activity, were predominant. Metagenomically assembled genomes further revealed Lactococcus's substantial role in producing flavors and active compounds, including amino acids and peptides. This study offers novel perspectives to the foodization and high-value utilization of cassava by-products, emphasizing the sustainable exploitation of biomass resources.