Antibacterial effect of extracts of Hermetia illucens (Diptera: Stratiomyidae) larvae against Gram‐negative bacteria

Abstract

Larvae of the black soldier fly, Hermetia illucens are well‐known fly larvae that inhabit many countries around the world. Antimicrobial agents derived from the larvae may be among the substances that are produced in the body for their survival. This study was carried out to identify the antimicrobial effects of H. illucens larvae that commonly inhabit animal waste and food waste. To evaluate the pharmacological effects of H. illucens larvae extracts, the larvae were extracted by various organic solvents, and their antibacterial effects were determined by antimicrobial methods, such as agar disk diffusion and turbidometric assays. The methanol extracts (ME) indicated antibacterial effects against the proliferation of Klebsiella pneumoniae, Neisseria gonorrhoeae and Shigella sonnei. However, antibacterial effects were not induced in Gram‐positive bacteria such as Bacillus subtilis, Streptococcus mutans and Sarcina lutea. The bacterial growth treated with ME was strongly inhibited from 20 mg/mL in a dose‐dependent manner compared with other extracts, and antibacterial activity gradually decreased after 24 h. Moreover, the minimal inhibitory concentration (MIC) values of ME against Klebsiella pneumoniae, Neisseria gonorrhoeae and Shigella sonnei for 12 h were measured as 44.74 mg/mL, 43.98 mg/mL and 43.96 mg/mL, respectively. These results demonstrate that ME of H. illucens larvae not only has antibacterial activity which strongly inhibits the growth and proliferation of the bacteria but also unique properties which effectively block the viability of the bacteria.

High waste-to-biomass conversion and efficient Salmonella spp. reduction using black soldier fly for waste recycling

“…The authors speculated that the antibacterial effect could be due to interaction between the bacterial ribosome or bacterial cell wall and the active substance. In accordance with Choi et al (2012), a reduction was seen for the Gram-negative salmonella and some reduction for thermotolerant coliforms in this study, while no reduction of the Grampositive enterococcus occurred.…”

“…The mechanism behind the reduction of salmonella observed in this study is not known. Choi et al (2012) found that methanol extracts of the black soldier larvae had antibacterial effects on the Gram-negative bacteria studied, but no such effect was seen on the Grampositive ones. The authors speculated that the antibacterial effect could be due to interaction between the bacterial ribosome or bacterial cell wall and the active substance.…”

Insect proteins as a potential source of antimicrobial peptides in livestock production. A review

“…Methanol extracts of H. illucens larvae showed antibacterial effects against K. pneumoniae, Neisseria gonorrhoeae and Shigella sonnei. However, these extracts showed no antibacterial effects against Gram-positive bacteria such as B. subtilis, Streptococcus mutans and Sarcina lutea (Choi et al, 2012).…”

“…The majority of insect AMPs was isolated from the haemolymph of experimentally infected insects (Dang et al, 2010;Choi et al, 2012;Park et al, 2014Park et al, , 2015Kim et al, 2016), where they are produced in the fat body and in different epithelia. The production of specific AMPs targeted at a specific pathogen may be induced by septic injury by the respective pathogen inducing quick production of antimicrobial peptides (Kim et al, 2016).…”

Melanin properties at the different stages towards life cycle of the fly Hermetia illucens

“…It is shown that the antibacterial effect has methanolic extract larvae H. illucens (Choi W. H. et al, 2012). Our studies have shown that the antibacterial activity has melanin suspension in ethanol, which, apparently, due to the solubility of the melanin.…”