Biochar-amended composting of lincomycin fermentation dregs promoted microbial metabolism and reduced antibiotic resistance genes

Improper disposal of antibiotic fermentation dregs poses a risk of releasing antibiotics and antibiotic resistant bacteria to the environment. Therefore, this study evaluated the effects of biochar addition to lincomycin fermentation dregs (LFDs) composting. Biochar increased compost temperature and enhanced organic matter decomposition and residual antibiotics removal. Moreover, a 1.5-to 17.0-fold reduction in antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) was observed. Adding biochar also reduced the abundances of persistent ARGs hosts (e.g., Streptomyces, Pseudomonas) and ARG-related metabolic pathways and genes (e.g., ATP-binding cassette type-2 transport, signal transduction and multidrug efflux pump genes). By contrast, compost decomposition improved due to enhanced metabolism of carbohydrates and amino acids. Overall, adding biochar into LFDs compost reduced the proliferation of ARGs and enhanced microbial community metabolism. These results demonstrate that adding biochar to LFDs compost is a simple and efficient way to decrease risks associated with LFDs composting.

Automated summary

This study evaluated the effects of adding biochar to lincomycin fermentation dregs (LFDs) composting and found that it can increase compost temperature, enhance organic matter decomposition and remove residual antibiotics. It also reduces the quantity of antibiotic resistance genes and mobile genetic elements, as well as the abundance of persistent ARGs hosts and related metabolic pathways and genes. At the same time, compost decomposition is improved due to enhanced metabolism of carbohydrates and amino acids. Overall, adding biochar to LFDs compost is a simple and efficient way to reduce the risks associated with LFDs composting.