Effect of Chinese medicinal herbal residues on microbial community succession and anti-pathogenic properties during co-composting with food waste

• Chinese medicine herbal residue can be a potential bulking agent/co-substrate.
• CMHR did not inhibit the microbes but influenced the diversity and dominance.
• Food waste–CMHR co-compost showed inhibitory activity against two fungal pathogens.
• CMHR-born active ingredients are the main cause of inhibition.
• Increased population of microbial antagonists contribute to the inhibitory activities.

This study investigated the antimicrobial properties of Chinese medicinal herbal residues (CMHRs) during its co-composting with food waste (FW) in two different ratios along with a control. Inhibition on total microbial population were assessed while the numerically dominant microbes were isolated and their antagonistic effects were assessed. Results indicate that the active ingredients persist in the composting mass did not affect the microbes unspecifically as revealed from almost similar bacterial and fungal populations. Rather specific inhibitory activities against Alternaria solani and Fusarium oxysporum were observed. Apart from the CMHR-born active compounds, CMHR-induced changes in the antagonistic and mycoparasitic abilities of the bacteria and fungi also contribute to the specific inhibition against the tested pathogens. Therefore use of CMHRs during the composting of CMHRs enhances its antipathogenic property resulting in an anti-pathogenic compost.