Chemolithotrophic processes in the bacterial communities on the surface of mineral-enriched biochars.
Biochar and mineral-enriched biochar (MEB) have been used as soil amendments to improve soil fertility, sequester carbon and mitigate greenhouse gas emissions. Such beneficial outcomes could be partially mediated by soil bacteria, however little is known about how they directly interact with biochar or MEB. We therefore analyzed the diversity and functions of bacterial communities on the surfaces of one biochar and two different MEBs after a 140-day incubation in soil. The results show that the biochar and the MEBs harbor distinct bacterial communities to the bulk soil. Communities on biochar and MEBs were dominated by a novel Gammaproteobacterium. Genome reconstruction combined with electron microscopy and high-resolution elemental analysis revealed that the bacterium generates energy from the oxidation of iron that is present on the surface. Two other bacteria belonging to the genus Thiobacillus and a novel group within the Oxalbacteraceae were enriched only on the MEBs and they had the genetic capacity for thiosulfate oxidation. All three surface-enriched bacteria also had the capacity to fix carbon dioxide, either in a potentially strictly autotrophic or mixotrophic manner. Our results show the dominance of chemolithotrophic processes on the surface of biochar and MEB that can contribute to carbon sequestration in soil.
Centre for Marine Bio-Innovation, The University of New South Wales, Sydney, New South Wales, Australia.|School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, New South Wales, Australia.
Jun
J
Ye
School of Materials Science and Engineering, The University of New South Wales, Sydney, New South Wales, Australia.|Institute of Resource, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, Nanjing, China.
Stephen D
SD
Joseph
School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, New South Wales, Australia.
Mukan
M
Ji
Centre for Marine Bio-Innovation, The University of New South Wales, Sydney, New South Wales, Australia.
Shaun
S
Nielsen
Australian Institute of Innovative Materials, University of Wollongong, Wollongong, New South Wales, Australia.
David R G
DRG
Mitchell
School of Environmental and Life Sciences, University of Newcastle, Newcastle, New South Wales, Australia.
Scott
S
Donne
Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong, New South Wales, Australia.
Joseph
J
Horvat
Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong, New South Wales, Australia.
Jianli
J
Wang
School of Materials Science and Engineering, The University of New South Wales, Sydney, New South Wales, Australia.
Paul
P
Munroe
Centre for Marine Bio-Innovation, The University of New South Wales, Sydney, New South Wales, Australia.|School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, New South Wales, Australia.
Torsten
T
Thomas
D001419:Bacteria / Q000302:isolation & purification; D057965:Carbon Sequestration; D002606:Charcoal; D052837:Chemoautotrophic Growth; D020563:Gammaproteobacteria / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008903:Minerals; D042802:Oxalobacteraceae / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012987:Soil; D012988:Soil Microbiology; D013855:Thiobacillus / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
D008903:Minerals; D012987:Soil; C540010:biochar; D002606:Charcoal