The invention pertains to a recombinant bacterium with enhanced ethanol production characteristics when cultivated in a growth medium comprising glycerol. The recombinant bacterium comprises an inserted heterologous gene encoding glycerol dehydrogenase, and/or an up-regulated native gene encoding glycerol dehydrogenase. Particularly there is provided the recombinant bacterium BG1G1 of the Thermoanaerobacter mathranii species with an inserted heterologous gene encoding the E.C. 1.1.1.6 type, a NAD dependent glycerol dehydrogenase obtained from Thermotoga maritima.