The phrase "electron donor" refers to a substance or element that gives away its electrons to another substance during a chemical reaction. Full definition
There are also electron donors serving as meta directing groups. (osti.gov)
Also called OXPHOS Complexes (Oxidative Phosphorylation) that make redox NADPH be used as electron donor through ETC and allow mitochondria to produce cell energy ATP. (fightaging.org)
Years ago, Jetten and his team drew up a table chart with available electron donors and acceptors, that should allow for the growth of — still unknown — microorganisms. (sciencedaily.com)