Institute for Agro-Environmental Sciences, NARO

Bioconversion Process Unit

The recent rapid increase of the atmospheric concentrations of greenhouse gases (GHGs), such as N2O, CH4, and CO2, accelerates global warming phenomenon. Farmland and agricultural activities are thought of as important sources of GHGs and application of nitrogen fertilizer is considered as major sources of N2O emission in particular. Soil microorganisms, such as ammonia-oxidizing bacteria and ammonia-oxidizing archaea which promote nitrification and/or denitrification of nitrogen sources, are closely correlated with N2O generation (Figure) in farmland.
Our research unit in this area focuses particularly on 1) deciphering the processes involved in GHGs emission from the view of the activities of soil microorganisms, and analyzing nitrogen cycle over the whole crop production process so as to enable accurate quantitative assessments of N2O generation in farmland, and 2) devising future farmland management options considering the amount of GHG emissions, which especially contributes for curbing N2O generation. Our unit also aim to develop new technologies which promote recycling unutilized agricultural resources by using specific characters of environmental microorganisms in rural area.

Unit Leader

Research Topics : Biological soil disinfestation, Ethanol fermentation

Unit Members

Research Topics
Masahito HAYATSU Senior Principal Researcher Nitrification and denitrification
Yuko T. HOSHINO Principal Researcher Soil microbial community and N2O emission
Yoriko SAKAI Senior Researcher Soil biology in paddy field
Kanako TAGO Senior Researcher Ecology of denitrifying bacteria and insecticide-degrading bacteria

Research Publications

  • Itakura M. et al. (2013) Mitigation of nitrous oxide emissions from soils by Bradyrhizobium japonicum inoculation. Nature Climate Change 3: 208-212.
  • Akiyama H., Hoshino T.Y., Itakura M. (equally contributed) et al. (2016) Mitigation of soil N2O emission by inoculation with a mixed culture of indigenous Bradyrhizobium diazoefficiens. Scientific Reports 6:32869.
  • Sakai Y. et al. (2014) A 2,4-dichlorophenoxyacetic acid degradation plasmid pM7012 discloses distribution of an unclassified megaplasmid group across bacterial species. Microbiology 160: 525-536.
  • Tago K. et al. (2015) Insecticide applications to soil cotribute to the development of Burkholderia mediating insecticide resistance in stinkbugs. Molecular Ecology 24: 3766-3778.
  • Horita M. et al. (2015) On-farm solid state simultaneous saccharification and fermentation of whole crop forage rice in wrapped round bale for ethanol production. Biotechnology for Biofuels 8: 9.
Corporate Number 7050005005207