'Minimal metabolism': A key concept to investigate the origins and nature of biological systems

The systems view on life and its emergence from complex chemistry has remarkably increased the scientific attention on metabolism in the last two decades. However, during this time there has not been much theoretical discussion on what constitutes a metabolism and what role it actually played in biogenesis. A critical and updated review on the topic is here offered, including some references to classical models from last century, but focusing more on current and future research. Metabolism is considered as intrinsically related to the living but not necessarily equivalent to it. More precisely, the idea of "minimal metabolism", in contrast to previous, top-down conceptions, is formulated as a heuristic construct, halfway between chemistry and biology. Thus, rather than providing a complete or final characterization of metabolism, our aim is to encourage further investigations on it, particularly in the context of life's origin, for which some concrete methodological suggestions are provided. Also see the video abstract here: https://youtu.be/DP7VMKk2qpA.
This work was carried out as part of a Horizon 2020 Marie Curie ITN (“ProtoMet”—Grant Agreement no. 813873 with the European Commission), within which NL obtained a PhD fellowship. KR-M also acknowledges support from the Basque Government (Grant IT 1228-19) and the Spanish Ministry of Science and Innovation (PID2019-104576GB-I00).