Mitigation of Laughing Gas Emissions
by Nitrous Oxide Respiring
Microorganisms
Jörg Simon
Abstract
Nitrous oxide (N 2 O, laughing gas) is a potent greenhouse gas and ozonedepleting molecule. Since its atmospheric concentration is constantly rising,
N 2 O contributes significantly to the imminent climate crisis. A considerable
portion of N 2 O emissions has been recognized to be anthropogenic, mainly
originating from extensive agriculture needed to feed an ever-increasing world
population. In this context, biologically catalysed N 2 O reduction to dinitrogen
gas (N 2 ) is clearly a desirable process for humankind. Various microbial species
have been described to produce the copper cluster-containing enzyme N 2 O
reductase (NosZ), which is the only known enzyme that converts N 2 O to N 2 .
NosZ functions as the terminal reductase of anaerobic N 2 O respiration, which
conserves energy through proton motive force generation. In this chapter, the
physiological trait of N 2 O respiration is presented on the organismic, genomic
and enzymatic levels including the biosynthesis of NosZ and the architecture of
different kinds of dedicated electron transport chains that sustain N 2 O
respiration. In addition, conceivable strategies to mitigate N 2 O emissions are
discussed including bioaugmentation and engineering strategies for efficient and
robust N 2 O-respiring microorganisms.
Keywords
Anaerobic respiration Á Clade I and clade II nitrous oxide reductase Á Climate
change Á Greenhouse gas Á Nitrous oxide (N 2 O laughing gas) respiration Á
nos gene cluster Á NosZ
J. Simon (&)
Department of Biology, Microbial Energy Conversion and Biotechnology,
Technical University of Darmstadt, Darmstadt, Germany
e-mail: simon@bio.tu-darmstadt.de
© Springer Nature Switzerland AG 2021
J. J. G. Moura et al. (eds.), Enzymes for Solving Humankind's Problems,
https://doi.org/10.1007/978-3-030-58315-6_7
185
by Nitrous Oxide Respiring
Microorganisms
Jörg Simon
Abstract
Nitrous oxide (N 2 O, laughing gas) is a potent greenhouse gas and ozonedepleting molecule. Since its atmospheric concentration is constantly rising,
N 2 O contributes significantly to the imminent climate crisis. A considerable
portion of N 2 O emissions has been recognized to be anthropogenic, mainly
originating from extensive agriculture needed to feed an ever-increasing world
population. In this context, biologically catalysed N 2 O reduction to dinitrogen
gas (N 2 ) is clearly a desirable process for humankind. Various microbial species
have been described to produce the copper cluster-containing enzyme N 2 O
reductase (NosZ), which is the only known enzyme that converts N 2 O to N 2 .
NosZ functions as the terminal reductase of anaerobic N 2 O respiration, which
conserves energy through proton motive force generation. In this chapter, the
physiological trait of N 2 O respiration is presented on the organismic, genomic
and enzymatic levels including the biosynthesis of NosZ and the architecture of
different kinds of dedicated electron transport chains that sustain N 2 O
respiration. In addition, conceivable strategies to mitigate N 2 O emissions are
discussed including bioaugmentation and engineering strategies for efficient and
robust N 2 O-respiring microorganisms.
Keywords
Anaerobic respiration Á Clade I and clade II nitrous oxide reductase Á Climate
change Á Greenhouse gas Á Nitrous oxide (N 2 O laughing gas) respiration Á
nos gene cluster Á NosZ
J. Simon (&)
Department of Biology, Microbial Energy Conversion and Biotechnology,
Technical University of Darmstadt, Darmstadt, Germany
e-mail: simon@bio.tu-darmstadt.de
© Springer Nature Switzerland AG 2021
J. J. G. Moura et al. (eds.), Enzymes for Solving Humankind's Problems,
https://doi.org/10.1007/978-3-030-58315-6_7
185