Adding siderophores: A new strategy to reduce greenhouse gas emissions in composting

Microbial community is the primary driver causing the greenhouse gas emissions in composting. Thus, regulating the microbial communities is a strategy to reduce them. Here, two different siderophores (enterobactin and putrebactin) were added, which could bind and translocate iron by specific microbes, to regulate the composting communities. The results showed that adding enterobactin enriched Acinetobacter and Bacillus with specific receptors by 6.84-fold and 6.78-fold. It promoted carbohydrate degradation and amino acid metabolism. This resulted in a 1.28-fold increase in humic acid content, as well as a 14.02% and 18.27% decrease in CO₂ and CH₄ emissions, respectively. Meanwhile, adding putrebactin boosted the microbial diversity by 1.21-fold and enhanced potential microbial interactions by 1.76-fold. The attenuated denitrification process led to a 1.51-fold increase in the total nitrogen content and a 27.47% reduction in N₂O emissions. Overall, adding siderophores is an efficient strategy to reduce greenhouse gas emissions and promote the compost quality.