Co-fermentation of palm oil mill effluent (POME) for hydrogen production by Thermoanaerobacterium thermosaccharolyticum PSU-2 under thermophilic condition was investigated. Hydrogen production from co-fermentation POME with 5 g/L decanter cake and without was 2.6 and 1.7 L-H-2/L-POME. Co-fermentation of POME with decanter cake enhanced hydrogen production. Tbm. thermosaccharolyticum PSU-2 augmentation at 20% v/v was found to be an efficient start-up strategy in continuous hydrogen production from co-fermentation of POME with decanter cake. Tbm. thermosaccharolyticum PSU-2 augmentation could suppress normal flora bacteria in POME and decanter cake. Hydrogen production of 7.2 L-H-2/L-POME and hydrogen production rate of 18.1 mmol-H-2/L/h was achieved from continuous hydrogen in long term operation. The soluble metabolites were dominated by acetic acid and butyric acid. Tbm. thermosaccharolyticum PSU-2 augmentation could use for control undesired bacteria in the hydrogen production system with flavored Thermoanaerobacterium sp. as dominant species. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.