The case for a wider range of flies for use in waste bioconversion

Abstract

Bioconversion is the process whereby nutrients are recovered from organic waste products, often by flies, to produce value-added products such as protein for animal feed and lipids for biodiesel production. Currently, research and industry focus on a select few fly species for use in bioconversion that are generalists in their feeding behaviour, the black soldier fly, Hermetia illucens L., and the housefly, Musca domestica L. More investigation is needed on species of flies that are more suited to underutilised waste streams, including meat processing waste. Species of flies that breed in carrion, such as blowflies (Calliphoridae) and flesh flies (Sarcophagidae) can be used to reduce meat processing waste and produce a valuable source of protein. In this review, we propose more investigation and use of a wider range of fly species for bioconversion of organic waste. Four blowfly species are recommended for use in the bioconversion of meat processing waste or a mixture of manure waste and meat processing waste. Chrysomya chloropyga (Wiedemann) is a large mammal carcass specialist and has been found to be effective at recovering nutrients from abattoir waste within four days and producing large larvae in the process. Chrysomya putoria (Wiedemann) and Chrysomya megacephala (Wiedemann) naturally breed in carrion and faeces, are associated with pit latrines and respond well under mass rearing conditions, with high egg production. These species would be recommended for a large-scale bioconversion facility that receives mixed waste streams including manure and animal remains. Lucilia sericata is known to produce antimicrobial compounds that assist in wound healing and has been frequently bred and studied and responds well to lab and mass rearing conditions. We recognise the potential obstacles to using alternative species in industrial-scale bioconversion facilities and pose future directions for research to overcome these challenges.