Earthworm Farming for Enhanced Protein Upcycling from Spent Mushroom Substrate

Abstract

Earthworm farming offers a sustainable approach to converting organic waste into high-quality protein, enhancing nutrient recycling and food systems circularity. This study explored the protein upcycling potential of two earthworm species, Eisenia fetida and Eudrilus eugeniae, assessing their productivity and nutritional composition when farmed on spent mushroom substrate (SMS) derived from oyster mushroom production on maize stover and on maize stover. Results showed that farming earthworms on SMS significantly increased biomass gains compared to maize stover alone, while species differences were inconclusive. E. fetida contained higher total amino acid levels than E. eugeniae, yet both species exhibited high protein quality. Using Ugandan maize stover yields, we estimated that up to 29 kg of crude protein per hectare annually could be upcycled through consecutive oyster mushroom and earthworm farming, underscoring the potential of this waste-to-protein pathway for food security.

Keywords: vermiculture, circularity, essential amino acid, alternative protein source, Eisenia fetida, Eudrilus eugeniae