Algae biomass is considered as a promising energy feedstock, and bioenergy recovery from algae can be significantly enhanced by pretreatment. This study compared the effect of different pretreatment methods, including heat, acid, base, heat-acid and heat-base on macroalgae Saccharina japonica, and dark fermentation was conducted to achieve a couple generation of bioenergy and biomaterials. All the pretreatment could enhance the hydrogen production and energy recovery from macroalgae, and the combined pretreatment showed significant advantage in organics solubilization. Heat-base pretreated macroalgae achieved the highest hydrogen yield (17.5 mL/g TSadded), while highest total energy conversion efficiency (35.4%) was obtained from heat-acid pretreated macroalgae, which was 2.1- and 2.9-fold compared to the control test. Hydrogen production can be further enhanced by microbial acclimation to high Na+ concentration to relieve its inhibition. (C) 2019 Elsevier Ltd. All rights reserved.