Livestock manure valorisation using black soldier fly bioconversion: Current advances, process integration, and pathways toward carbon neutrality

Achieving net-zero GHG emissions in livestock farming is an urgent priority, particularly in the management of livestock manure, which is a major source of greenhouse gas (GHG) emissions. Recently, black soldier fly larvae (BSFL) have attracted increasing attention as biological agents for manure reduction and resource recovery. This review summarises the current state of BSFL-based livestock manure treatment, with particular emphasis on GHG emissions and mitigation strategies. Despite the rapid growth of BSFL research, only a limited number of studies have directly monitored and quantified GHG emissions during manure bioconversion. Among the three major GHGs associated with livestock manure management-carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O)-CO₂ has consistently been identified as the predominant gas emitted during BSFL-based bioconversion. Although BSFL treatment produces lower GHG emissions than conventional manure management methods, it remains a net source of GHG emissions. Therefore, this review proposes integrating BSFL-based treatment with complementary biological and thermochemical processes. These integrated platforms have the potential to improve manure valorisation and support the achievement of net-zero GHG emissions. In addition, this review identifies key knowledge gaps and future research priorities to improve the environmental performance, process efficiency and practical applicability of BSFL-based livestock manure bioconversion.