Insides into molecular structural elucidation on the pesticidal and herbicidal potency of AD biogas slurry

Biogas slurry is the residue liquid after anaerobic fermentation of biomass. The bio-slurry has the potential to promote plant growth and control pests. This study explores the pesticidal potency of anaerobic digestate focusing on structural elucidation through gas chromatography–mass spectrometry analysis. Samples were collected from three anaerobic digesters processing cow dung, mixed substrates, and pig waste. Physicochemical parameters such as pH, electrical conductivity, total dissolved solids, and nitrogen content were measured. The slurries exhibited slightly basic pH values (7.5–7.8) and electrical conductivity (13.8–21.9 mS/m). GC–MS analysis revealed diverse phytochemical compounds in the bio-slurries, such as gramine, 2,2-dimethoxybutane, and 4-methyl-3-penten-2-one, with potential pesticidal properties. Gramine exhibited insecticidal, herbicidal, and algaecidal effects, while 2,2-dimethoxyethane demonstrated fungicidal and herbicidal properties. Gramine was identified and possesses its potential as a natural biopesticide. The identified compounds offer promising alternatives to synthetic pesticides, emphasizing the potential of biogas slurry as a sustainable biopesticide resource.