Antimicrobial Biomasses from Lactic Acid Fermentation of Black Soldier Fly Prepupae and Related By-Products

Abstract

Worldwide, thousands of insect species are consumed as food or are used as feed ingredients. Hermetia illucens, ‘black soldier fly’, is one of them, and a large amount of puparia and dead adults flies are accumulated during rearing. These materials represent important wastes but no studies are still present in the literature regarding their functional properties and potential reuse. Lactic acid bacteria (LAB) are a heterogeneous group of bacteria contributing to various industrial applications, ranging from food fermentation, chemicals production to pharmaceuticals manufacturing. A LAB feature of industrial interest is their ability to produce antimicrobial metabolites. Considering the scientific and commercial interest in discovering novel antimicrobials, this work will be direct towards fermentation of insect-derived biomasses: puparia and adults insect at the end of life cycle. To the best of our knowledge, the in vitro antimicrobial activity of fermented insects is tested for the first time. This study aimed also to evaluate differences in the composition between fermented and unfermented insects, and to study whether the fermentation and the type of LAB used played a crucial role in modifying the composition of the substrate. Results firstly highlighted fermentability of this species of insects, showed that fermented black soldier flies puparium possess a high antimicrobial activity against tested pathogens. Moreover, result of chemical composition showed that fermented biomass had a higher percentage of fat and a more complex fatty acids profile.

Dynamic changes in molecular composition of black soldier fly prepupae and derived biomasses with microbial fermentation

“…The BSF prepupae and derived biomasses (puparia and adult flies) were kindly provided by the Laboratory of Applied Entomology – BIOGEST-SITEIA, Department of Life Science, University of Modena and Reggio Emilia, Reggio Emilia (RE), Italy. The breeding conditions of BSF larvae until they reach the prepupae stage have been previously reported ( Hadj Saadoun et al, 2020 ). Briefly, larvae were reared at 27 °C and 70% relative humidity and fed at libitum with the Gainesville Housefly diet (50% wheat bran, 30% alfalfa meal and 20% corn meal).…”

“…Fermentation of BSF samples was carried out as reported by Hadj Saadoun et al (2020) . Briefly, Lacticaseibacillus rhamnosus 1473 isolated from Parmigiano Reggiano cheese, and Lactiplantibacillus plantarum 285, isolated from Brazilian cheese, were chosen for fermentation.…”

“…In a previous work, a LAB fermentation by using two different strains, Lacticaseiobacillus rhamnosus (1473) and Lactiplantiobacillus plantarum (285) , was applied as a method to confer antimicrobial activity to BSF prepupae and derived biomasses. A preliminary compositional analysis of the BSF biomasses after fermentation suggested some nutrients modifications ( Hadj Saadoun et al, 2020 ). In this work the molecular composition of BSF and their derived waste before and after fermentation was deeply explored and fermentation was proposed as a method to further enhance these unconventional biomasses.…”

Influence of Processing Parameters and Natural Antimicrobial on Alicyclobacillus acidoterrestris and Clostridium pasteurianum Using Response Surface Methodology

“…Moreover, the antibacterial activity of fermented extracts/substrate starting from by-products is poorly reported [ 27 , 28 , 29 ].…”

Bacterial challenge-associated metabolic phenotypes in Hermetia illucens defining nutritional and functional benefits

“…Given that the robust immune system of BSF plays an important role in improvement of feeding and bioactive compound synthesis, bacterially-challenged immunity is one of the main approaches used nowadays 7 . Different bacterial strains were applied to trigger biological processes in BSF larvae in studying nutritional immunology, purification, and characterisation of novel bioactive compounds such as AMPs and fatty acids 13 – 19 . The results, notably, showed the enhanced antimicrobial abilities against various strains of Gram-negative 13 , 14 , 16 – 18 and Gram-positive bacteria 15 – 17 , fungi 16 , and proposed potentials of antiviral and anticancer properties 13 , 20 .…”