Black Soldier Fly Larvae Can Effectively Degrade Oxytetracycline Bacterial Residue by Means of the Gut Bacterial Community.

Cuncheng Liu,Cunwen Wang,Huaiying Yao

doi:10.3389/fmicb.2021.663972

Abstract

Antibiotic bacterial residue is a unique hazardous waste, and its safe and effective disposal has always been a concern of pharmaceutical enterprises. This report presents the effective treatment of hazardous waste—antibiotic bacterial residue—by black soldier fly larvae (larvae), oxytetracycline bacterial residue (OBR), and soya meal with mass ratios of 0:1 (soya), 1:20 (OBRlow), and 1:2 (OBRhigh), which were used as substrates for larval bioconversion. Degradation of OBR and oxytetracycline, the bacterial community, the incidence of antibiotic resistance genes (ARGs) and the bacterial function in the gut were examined. When the larvae were harvested, 70.8, 59.3, and 54.5% of the substrates had been consumed for soya, OBRlow and OBRhigh; 65.9 and 63.3% of the oxytetracycline was degraded effectively in OBRlow and OBRhigh, respectively. The larval bacterial communities were affected by OBR, abundant and various ARGs were discovered in the gut, and metabolism was the major predicted function of the gut. These findings show that OBR can be digested and converted by larvae with gut bacteria, and the larvae can be used as a bioremediation tool for the treatment of hazardous waste. Finally, the abundant ARGs in the gut deserve further attention and consideration in environmental health risk assessments.

Highlights

During the production of antibiotics, waste antibiotic bacterial residue is generated
When the oxytetracycline bacterial residue (OBR) content increased, the larval weight decreased, and larval development was significantly affected by the different substrates (ANOVA test) in proportion to substrate consumption
Most of the larvae escaped from the substrates when the OBR content was high, and toxic components, such as byproducts, metabolic products, and especially oxytetracycline residues (Guo et al, 2012), which remained in the OBR may exceed the selection pressure on larvae to digest and convert substates

Summary

Introduction

During the production of antibiotics, waste antibiotic bacterial residue is generated. Practical, and effective methods for dealing with antibiotic bacterial residue include composting, anaerobic digestion, combination with yeast extract products, mixing with coal water slurry, and modification of the bacterial residue to form activated carbon (Kakimoto and Funamizu, 2007; Kakimoto et al, 2007; Zhou et al, 2011, 2012; Li et al, 2012). These methods have high processing costs and produce varying degrees of secondary pollutants

Methods

Results

Conclusion