Oxidoreduction-driven transporters. Transport systems that drive transport of a solute (e.g., an ion) energized by the exothermic flow of electrons from a reduced substrate to an oxidized substrate are included in this subclass. These are found in many prokaryotes as well as mitochondria, chloroplasts and other eukaryotic organelles. In the bacterial domain, lactic acid bacteria such as Lactococcus lactis, facultative anaerobes largely dependent on fermentation, have been shown to possess functional electron transfer chains (Brooijmans et al., 2007; see 3.D.4).  Marreiros et al. 2016 have reviewed the different types of membrane electron transfer chains (e.g., quinone reductases, quinol electron carriers, oxidoreductases, terminal electron acceptors, etc.)