Black soldier fly larvae for organic manure recycling and its potential for a circular bioeconomy: A review

Livestock farming and its products provide a diverse range of benefits for our day-to-day life. However, the ever-increasing demand for farmed animals has raised concerns about waste management and its impact on the environment. Worldwide, cattle produce enormous amounts of manure, which is detrimental to soil properties if poorly managed. Waste management with insect larvae is considered one of the most efficient techniques for resource recovery from manure. In recent years, the use of black soldier fly larvae (BSFL) for resource recovery has emerged as an effective method. Using BSFL has several advantages over traditional methods, as the larvae produce a safe compost and extract trace elements like Cu and Zn. This paper is a comprehensive review of the potential of BSFL for recycling organic wastes from livestock farming, manure bioconversion, parameters affecting the BSFL application on organic farming, and process performance of biomolecule degradation. The last part discusses the economic feasibility, lifecycle assessment, and circular bioeconomy of the BSFL in manure recycling. Moreover, it discusses the future perspectives associated with the application of BSFL. Specifically, this review discusses BSFL cultivation and its impact on the larvae's physiology, gut biochemical physiology, gut microbes and metabolic pathways, nutrient conservation and global warming potential, microbial decomposition of organic nutrients, total and pathogenic microbial dynamics, and recycling of rearing residues as fertilizer.