The influence of surfactant addition on the hydrogen fermentative of the organic fraction of municipal solid waste was extensively investigated under thermophilic conditions (55 +/- 2 degrees C) in batch cultures. The addition of Tween 80 (R) (T80) and polyethylene glycol (PEG 6000) substantially improved hydrogen yields (HYs) resulting in 109.9 +/- 7.1 and 113.8 +/- 7.7 mlH(2)/gCarb.(Initial) at T80 and PEG 6000 (R) concentrations not exceeding 2.8% and 16.7 g/L, respectively. A combination of 2.8% T80 with 1.7 g/L PEG 6000 (R) achieved slightly higher HYs of 116.7 +/- 5.2 mlH(2)/gCarb.(initial). An artificial neural network model reliably represented the relationship between the surfactant concentration and hydrogen production with a correlation coefficient (R-2) of 0.980. Microbial community analysis of the batches supplemented with 2.8% T80 and 1.7 g/L PEG 6000 (R) showed the dominance of the hydrogen-producing bacteria Enterobacter, Escherichia, Buttiauxella, and Pantoea. The study confirms the potential of surfactant addition for H-2 production from wastes containing organics in a particulate form. (C) 2015 Elsevier Ltd. All rights reserved.