|Yang, Z; Sun, T; Subdiaga, E; Obst, M; Haderlein, S; Maisch, M; Kretschmar, R; Angenent, LT; Kappler, A: Aggregation-dependent electron transfer via redox-active biochar particles stimulate microbial ferrihydrite reduction, Science of the Total Environment, 703, 135515 (2020), online: 2019-11-14, doi:10.1016/j.scitotenv.2019.135515|
Microbial Fe(III) reduction plays an important role for biogeochemical carbon and iron cycling in sediments and soils. Biochar is used as a soil amendment to increase fertility and lower N2O/CO2 emissions. It is redox-active and can stimulate microbial Fe(III) mineral reduction. It is currently unknown, however, how the aggregation of cells and Fe(III) minerals with biochar particles influence microbial Fe(III) reduction. Therefore, we determined rates and extent of ferrihydrite (Fh) reduction in S. oneidensis MR-1 cell suspensions with different particles sizes of wood-derived Swiss biochar and KonTiki biochar at different biochar/Fh ratios. We found that at small biochar particle size and high biochar/Fh ratios, the biochar, MR-1 cells and Fh closely aggregated, therefore addition of biochar stimulated electron transfer and microbial Fh reduction. In contrast, large biochar particles and low biochar/Fh ratios inhibited the electron transfer and Fe(III) reduction due to the lack of effective aggregation. These results suggest that for stimulating Fh reduction, a certain biochar particle size and biochar/Fh ratio is necessary leading to a close aggregation of all phases. This aggregation favors electron transfer from cells to Fh via redox cycling of the electron donating and accepting functional groups of biochar and via direct electron transfer through conductive biochar carbon matrices. These findings improve our understanding of electron transfer between microorganisms and Fe(III) minerals via redox-active biochar and help to evaluate the impact of biochar on electron transfer processes in the environment.
|Fr. 2020-07-10 now|
12th BayCEER Workshop 2020: "Call for Abstracts" is open
Extreme redox oscillations in freshwater re-flooded acid sulfate soil wetlands: Effects on Fe, S, and trace metals geochemical behavior
Dissolved organic matter quality in differently managed forest ecosystems
Signaling of rhizosphere microbiome: key for plant health, development and nutrition
BayCEER Workshop 2020
Why Science Communication?
Stoichiometric controls of C and N cycling
Flying halfway across the globe to dig in the dirt – a research stay in Bloomington, USA
Picky carnivorous plants?