The influence of 2-bromoethanesulfonate (BES) on anaerobic inocula, from a Wastewater Treatment Plant, was evaluated for enriching the hydrogen (H-2) production using sugarcane bagasse (SCB). The assays were carried out in 100 mL reactors at 37 degrees C under five conditions: A (without BES), B (Inoculum pretreated with 20 mM BES - 24 h), C (Inoculum pretreated with 20 mM BES - 30 min), D (10 mM BES in the culture medium) and E (20 mM BES in the culture medium). H-2 production reached the highest value (10.96 mmol/L) for condition D. Methane was detected in B (0.43 mmol/L) and C (0.73 mmol/L). The addition of BES in the culture medium inhibited the consumption of H-2 by methanogens. H-2 was produced primarily through the fermentation of acetic acid. Despite the absence of methane, Archaea was detected in sample D. The inoculum was favorable for H-2 production using SCB and the addition of 10 mM BES in the culture medium was the best strategy employed. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.