Liu Xiaofeng, research group of Chengdu Institute of biology, Chinese Academy of Sciences, made progress in the research of methane oxidation coupled denitrification in landfill

With the continuous development of economy and society, global warming and ecological deterioration caused by greenhouse effect has become a major threat to human survival and development Methane is an important gas that causes greenhouse effect, which is 20-30 times as much as carbon dioxide of the same mass Landfill is one of the important biological emission sources of methane, and its annual total methane emission is 20-70 TG It can be seen that the effective control of landfill methane emissions is of great significance to curb global warming At the same time, in the landfill with leachate recirculation, the concentration of nitrate is higher while ammonia nitrogen is removed It has been shown that methane oxidation can be coupled with denitrification for simultaneous removal of methane and nitrate pollution However, there is a lack of research on microbial biochemical pathway of methane oxidation coupled denitrification in landfill Cao Qin, a member of the research group of Liu Xiaofeng, Chengdu Institute of biology, Chinese Academy of Sciences, has carried out a series of researches on methane oxidation coupled denitrification in landfill site Under different oxygen concentration, methane oxidation coupled denitrification will be completed by different microbial cooperation and different reaction paths In order to study these cooperative microorganisms and explore their cooperative mechanism, firstly, the samples from different depths of the landfill were inoculated into the percolation bed bioreactor to construct two systems of micro oxygen and hypoxia In addition, the efficiency of methane oxidation and nitrate removal was studied Secondly, inoculate the concentrate into serum bottle for batch test, calculate the carbon and nitrogen balance, and deduce the chemical reaction formula in different systems Combined with the analysis of high-throughput sequencing of functional microorganisms, it was found that methanogens (methylobacter and Methylomonas) used oxygen as the electron acceptor to oxidize methane in the micro oxygen system, and released extracellular organic matter, which was used by denitrifying bacteria (methyloflaceae) to complete denitrification In anoxic system, methane oxidizing bacteria can directly use nitrate as the final electron acceptor to oxidize methane, and realize the reduction of nitrate at the same time The study of the coupling reaction not only extends the path of carbon and nitrogen cycle in landfill, but also provides a new idea and theoretical basis for the joint treatment of landfill gas and leachate The research was supported by the National Natural Science Foundation of China (51478448), the key laboratory open fund of the center for applied and Environmental Microbiology (klcas-2017-9), etc Relevant scientific research achievements were published on science of the total environment (DOI: 10.1016 / j.scittenv 2018.08.289) under the title of "measure oxidation coupled to Denitification under micro acoustic conditions in lead bed bioreactors" The corresponding author of this paper is Li Dong, an associate researcher of Chengdu Institute of biology.