Drug discovery-based approach identifies improved nitrification inhibitors

Abstract

Nitrogen (N) fertilization is crucial to sustain global food security, but fertilizer N production is energy-demanding and subsequent environmental N losses contribute to biodiversity loss and climate change. To mitigate the environmental impact of N-fertilizers, nitrification inhibitors can be applied to produce so-called enhanced efficiency fertilizers (EEFs), which effectively reduce nitrogen pollution. However, current nitrification inhibitors have limitations and do not target all nitrifying microorganisms. Hence, to identify broad-spectrum nitrification inhibitors, we adopted a drug discovery-based approach and screened 45,400 small molecules on different groups of nitrifying microorganisms. Although a high number of potential nitrification inhibitors were identified, none of them targeted all nitrifier groups. However, co-applying different types of inhibitors resulted in a synergistic effect, both in the reduction of ammonium consumption and greenhouse gas emissions, beyond what is achieved with currently applied nitrification inhibitors. This advocates for combining different types of nitrification inhibitors in EEFs to render agriculture more sustainable.

New high-throughput screening assays for nitrification inhibitors identify an oxazolidine-thione as biological nitrification inhibitor

“…Unfortunately, their efficacy varies with soil characteristics (e.g. pH and moisture content) and climate conditions (Yang et al, 2016;Guardia et al, 2018;Lam et al, 2022;Beeckman et al, 2023a). Moreover, DCD requires high application rates which sometimes leads to phytotoxic effects (Weiske et al, 2001;Wissemeier et al, 2001), while DMPP seems to have a low stability in certain soils (Doran et al, 2018;Sidhu et al, 2021).…”

“…The first and rate-limiting step in this microbial process is ammonia (NH3) oxidation, which is executed by the ammonia monooxygenase (AMO) enzyme in ammonia-oxidizing microorganisms. Subsequently, nitrite (NO2 -) is formed by the actions of the hydroxylamine dehydrogenase (HAO) enzyme and a yet unidentified component (Caranto and Lancaster, 2017;Beeckman et al, 2018;Beeckman et al, 2023a). Subsequent oxidation of NO2results in the formation of nitrate (NO3 -), serving together with ammonium (NH4 + ) as a N source for plants (Pélissier et al, 2021).…”