Bioconversion efficiencies, greenhouse gas and ammonia emissions during black soldier fly rearing – A mass balance approach. (20th October 2020)

• Record Type: Journal Article
• Authors: Parodi, Alejandro; De Boer, Imke J.M.; Gerrits, Walter J.J.; Van Loon, Joop J.A.; Heetkamp, Marcel J.W.; Van Schelt, Jeroen; Bolhuis, J. Elizabeth; Van Zanten, Hannah H.E.
• Is Part Of: Journal of cleaner production. Volume 271(2020)
• Publication Date: 2020-10-20
• Subjects: Hermetia illucens -- GHG -- Emissions -- Nitrogen -- Ammonia -- Bioconversion; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2020.122488
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: Black soldier fly larvae (BSFL) are acknowledged for their potential to upcycle waste biomass into animal feed, human food or biofuels. To ensure sustainable BSFL rearing, insight into nutrient bioconversion efficiencies and nutrient losses via gaseous emissions is key. This study used a mass balance approach to quantify nutrient bioconversion efficiencies (i.e., carbon, energy, nitrogen, phosphorus and potassium) and gaseous emissions (i.e., greenhouse gasses and ammonia) of BSFL reared on a substrate used in industrial production. On this substrate, bioconversion efficiencies ranged from 14% (potassium) to 38% (nitrogen). The proportion of dietary inputs found in the residues ranged from 55% (energy) to 86% (potassium), while the proportion of dietary inputs lost via gaseous emissions ranged from 1% (nitrogen) to 24% (carbon). Direct emissions of methane and nitrous oxide during rearing were 16.8 ± 8.6 g CO2 -equivalents per kg of dry BSFL biomass. Even though ammonia emissions were minimal, these could have been avoided if larvae would have been harvested before the CO2 peak was reached. Our results provide the first complete mass balance and comprehensive quantification of BSF larval metabolism and GHG emissions, required to assess and improve the environmental sustainability of BSFL production systems. Highlights: First complete and matching balance for carbon, nitrogen and energy of growing larvae. Bioconversion efficiencies were 20% for carbon, 22% for energy and 38% for nitrogen. Direct GHG emissions per kg of dry larval biomass gain were 16.8 ± 8.6 g CO2 eq. Ammonia emissions started after the peak of CO2 production was reached.