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Li T, Yang W, Gao Q, Wei M, Li H, Ma X, Wen T, Guo J, Jin D. Reducing the mass and decreasing the bioavailability of heavy mental from organic wastes treated by black soldier fly larvae. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 269:115821. [PMID: 38091670 DOI: 10.1016/j.ecoenv.2023.115821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 12/06/2023] [Accepted: 12/10/2023] [Indexed: 01/12/2024]
Abstract
Black soldier fly larvae (BSFL), Hermetia illucens L., are widely used to reduce the mass of various wastes. However, the potential metal tolerance mechanisms during periods of waste bioconversion by BSFL remain largely unknown. To further reveal the mechanisms, BSFL were used to treat the agricultural organic wastes, including pig manure (PM), cow manure (COM), spent mushroom substrate (SMS), and wet distiller grains (WDG). After these individual and combined waste(s) were treated by BSFL, we investigated the waste reduction rates and evaluated the responses of BSFL gut microbes to heavy metals of agricultural organic wastes. Additionally, the colloidal particles of residual wastes were characterized by combing energy dispersive X-ray (EDX) spectroscopy, Size potential, Zeta potential, and excitation-emission matrix (EEM) spectroscopy. Results indicated that the waste reduction rates were up to 74% in COM+WDG and 69% in WDG, most of heavy metals (e.g., Zn and Co) from organic wastes were not accumulated in the bodies of mature larvae after treatment. Further, results obtained from the prediction of gene function on the basis of 16 S rRNA data revealed that the presence of multi-resistance genes in the gut of BSFL can help the larvae resist Zn and/or Co stress. In addition, the drug sensitivity test implied that BSFL5_L and BSFL6_L from BSFL gut bacterial strains have multi-resistance to Co and Zn. Additionally, EDX results revealed that the colloidal particles in five waste residues after BSFL treatment are mainly consisted of Fe, Ca and Si, which can capture heavy metals (e.g., Cu, Mn). Results from EEM spectroscopy and PARAFAC showed that tryptophan-like and humic-like accumulatively account for 56%- 68% of all components. Importantly, these two components could strongly bind the metal elements and form colloidal particles with high stability, and therefore reduce the heavy metal pollution of agricultural organic wastes. Our findings offered an environment-friendly method to treat agricultural organic wastes, which would be far-reaching influence to our environment.
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Affiliation(s)
- Tao Li
- Institute of Entomology, Guizhou University, Guiyang 550025, PR China; Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture and Rural Affairs of the P. R. China, Guiyang 550025, PR China
| | - Wenmei Yang
- Institute of Entomology, Guizhou University, Guiyang 550025, PR China; Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture and Rural Affairs of the P. R. China, Guiyang 550025, PR China
| | - Qian Gao
- Institute of Entomology, Guizhou University, Guiyang 550025, PR China; Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture and Rural Affairs of the P. R. China, Guiyang 550025, PR China
| | - Mao Wei
- Institute of Entomology, Guizhou University, Guiyang 550025, PR China; Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture and Rural Affairs of the P. R. China, Guiyang 550025, PR China
| | - Haiyin Li
- Institute of Entomology, Guizhou University, Guiyang 550025, PR China; Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture and Rural Affairs of the P. R. China, Guiyang 550025, PR China
| | - Xinyi Ma
- Institute of Entomology, Guizhou University, Guiyang 550025, PR China; Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture and Rural Affairs of the P. R. China, Guiyang 550025, PR China
| | - Tingchi Wen
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Guiyang 550025, PR China
| | - Jianjun Guo
- Institute of Entomology, Guizhou University, Guiyang 550025, PR China; Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture and Rural Affairs of the P. R. China, Guiyang 550025, PR China.
| | - Daochao Jin
- Institute of Entomology, Guizhou University, Guiyang 550025, PR China; Scientific Observing and Experimental Station of Crop Pest in Guiyang, Ministry of Agriculture and Rural Affairs of the P. R. China, Guiyang 550025, PR China.
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