The relationship between material transformation, microbial community and amino acids and alkaloid metabolites in the mushroom residue-prickly ash seed oil meal composting with biocontrol agent addition

Abstract

This study investigated the effects of adding biocontrol microbes on metabolites and pathogenic microorganisms during mushroom residue composting and the relationships of metabolite changes with microbes and material transformation. The results showed that the addition of Bacillus subtilis (BS) and Trichoderma harzianum (TH) with mushroom residue promoted the conversion of organic carbon and nitrogen. The abundance of pathogenic microbes was increased in biocontrol microbial treatments. BS or TH treatments increased the levels of amino acids, carbohydrates, and bacteriostatic alkaloid metabolites. Network analysis revealed that the main microorganisms significantly related to alkaloid metabolites were Rhabdanaerobium, Atopostipes, Planifilum and Ureibacillus. The increased bacterial abundance and decreased NO₃^--N and TOC were closely related to the increases in amino acid and alkaloid metabolites after biocontrol agent treatments. Generally, adding biocontrol microbes is an effective way to increase the levels of antibacterial metabolites, but there is a risk of increasing the abundance of pathogenic microbes.

Keywords: Alkaloid metabolism; Biocontrol microbes; Compost metabolites; Mushroom residue; Pathogenic microbial community.