Department of Soil and Water Conservation and Waste Management, Centro de Edafología y Biología Aplicada del Segura (CEBAS-CSIC), Campus Universitario de Espinardo 30100 Murcia, Spain.
Geomicrobiology, Center for Applied Geosciences, University of Tübingen, Sigwartstrasse 10, 72074 Tübingen, Germany.
FEMS Microbiol Ecol. 2020 Aug 1;96(8). doi: 10.1093/femsec/fiaa133.
Biochar (BC) has been shown to influence microbial denitrification and mitigate soil N2O emissions. However, it is unclear if BC is able to directly stimulate the microbial reduction of N2O to N2. We hypothesized that the ability of BC to lower N2O emissions could be related not only to its ability to store electrons, but to donate them to bacteria that enzymatically reduce N2O. Therefore, we carried out anoxic incubations with Paracoccus denitrificans, known amounts of N2O, and nine contrasting BCs, in the absence of any other electron donor or acceptor. We found a strong and direct correlation between the extent and rates of N2O reduction with BC's EDC/EEC (electron donating capacity/electron exchange capacity). Apart from the redox capacity, other BC properties were found to regulate the BC's ability to increase N2O reduction by P. denitrificans. For this specific BC series, we found that a high H/C and ash content, low surface area and poor lignin feedstocks favored N2O reduction. This provides valuable information for producing tailored BCs with the potential to assist and promote the reduction of N2O in the pursuit of reducing this greenhouse gas emissions.
生物炭 (BC) 已被证明可以影响微生物反硝化作用并减少土壤 N2O 排放。然而，目前尚不清楚生物炭是否能够直接刺激微生物将 N2O 还原为 N2。我们假设生物炭降低 N2O 排放的能力不仅与其储存电子的能力有关，而且与其向具有酶促还原 N2O 能力的细菌提供电子的能力有关。因此，我们在不存在任何其他电子供体或受体的情况下，用已知量的 N2O 和九种不同的生物炭进行了 Paracoccus denitrificans 的缺氧孵育。我们发现，生物炭的 EDC/EEC（电子供体容量/电子交换容量）与 N2O 还原的程度和速率之间存在很强的直接相关性。除了氧化还原能力外，其他生物炭特性被发现可以调节生物炭促进 P. denitrificans 增加 N2O 还原的能力。对于这个特定的生物炭系列，我们发现高 H/C 和灰分含量、低表面积和较差的木质素原料有利于 N2O 还原。这为生产具有潜力的定制生物炭提供了有价值的信息，有助于促进 N2O 的还原，从而减少这种温室气体的排放。
