Glycerol is a low-cost carbon source that can be used to produce chemicals like ethanol or hydrogen (H-2). In the work described here, the biotransformation of crude glycerol, obtained from a biodiesel production process, into ethanol and H2 by Escherichia coli MG1655 was studied for batch and fed-batch operating modes. No difference was found between the use of crude glycerol rather than food-grade glycerol as the main carbon source. Three concentrations of crude glycerol were studied for fed-batch experiments under constant and exponential feeding regimes. No nutrients were added during the feeding step and a crude glycerol-water solution was fed into the reactor. The exponential feeding regime with 37.7 g L-1 of crude glycerol in the feed gave the best overall results, with 100% of fed crude glycerol consumed, a final ethanol concentration of 7.58 +/- 1.52 g L-1 and an H-2 yield of 0.56 mol mol(-1) of fed crude glycerol. The process was studied on a pilot scale (working volume: 200 L) in a closed loop mixed reactor, giving an ethanol concentration of 8.5 +/- 1.70 g L-1, thus indicating that scale-up of the process is possible. Fed-batch mode under an exponential feeding regime is a promising strategy to increase ethanol and H-2 production and crude glycerol utilization given that previous studies concerning the biotransformation of glycerol to ethanol and H-2 by Escherichia coli have mainly been performed in batch mode. Hydrodynamic characterization of the reactors was performed to establish conditions that would allow an approach to a complete mixing regime in all experiments. (C) 2016 Elsevier Ltd. All rights reserved.