Saccharomyces cerevisiae vs Escherichia coli in the valorization of crude glycerol to produce ethanol

Abstract

The transformation of crude glycerol into ethanol at a lab scale through Saccharomyces cerevisiae and Escherichia coli was evaluated. The fermentation using three concentrations (10, 20, and 30 g L−1) of crude glycerol was evaluated in 250 mL reactors; the growth of the microorganisms was also evaluated considering pure glycerol. Afterward, the microorganism showing the best performance fermenting crude glycerol was evaluated in a 7 L reactor. Both microorganisms could grow in pure and crude glycerol; the ethanol production with E. coli ranged from 0.17 to 0.45 g L−1 and from 0.49 to 0.60 g L−1 with S. cerevisiae in micro-reactors. In the 7 L reactor, S. cerevisiae could still grow, and a maximum ethanol production of 0.73 g L−1 was obtained. It is concluded that even if the yield production is low and more profound studies are required, S. cerevisiae could be used to revalorize crude glycerol.