Optimization of biohydrogen yield produced by bacterial consortia using residual glycerin from biodiesel production

The aims of this study were to simplify the fermentation medium and to optimize the conditions of dark fermentation of residual glycerin to produce biohydrogen. It was possible to remove all micronutrients of fermentation medium and improve biohydrogen production by applying residual glycerin as feedstock. After statistical analysis of the following parameters pH, glycerin concentration and volatile suspended solids, the values of 5.5; 0.5 g.L-1 and 8.7 g.L-1, respectively, were defined as optimum condition for this process. It generated 2.44 mol(H2)/mol(glycerin), an expressive result when compared to previous results reported in literature and considering that theoretical yield of H-2 from glycerol in dark fermentation process is 3 mol(H2)/mol(glycerol). This study allowed the improvement of yield and productivity by 68% and 67%, respectively. (C) 2016 Elsevier Ltd. All rights reserved.