ABSTRACT
The biological conversion of food waste (FW) into hydrogen (H2) by anaerobic fermentation is associated with high production costs and complex supplementation requirements. The present study focused on the simplification of the H2 production through dark fermentation (DF) by reusing its residual solid fraction, herein referred as DF-sludge, as nitrogen source for a subsequent FW conversion. The non-sterile FW fermentation with addition of C. butyricum as H2-producing microorganism and supplemented with two nitrogen sources was compared: ammonium chloride (NH4Cl) or DF-sludge. The maximum biogas productivity, H2 production yield and H2 cumulative production were obtained with the DF sludge supplementation, reaching values of 433.3 ± 34.3 mL biogas (L h)−1, 194.2 ± 24.4 mLH2 and 3.2 ± 0.0LH2L−1, respectively. The use of DF sludge improved the fermentation efficiency on H2 production by 40%, underlining the impact of nutrient recycling in C. butyricum fermentative performance.
