Biohythane production from marine macroalgae Sargassum sp. coupling dark fermentation and anaerobic digestion

The highest hydrogen and methane production yields, 91.3 ± 3.3 L kg−1 and 541 ± 10 L kg−1, respectively, were achieved with 2.5 g L−1 of Sargassum sp. (VS) and 0.09 g L−1of inoculum (CDW). The biogas produced contained 14-20% of hydrogen. Potential energy production from Sargassum sp. in two stage process was estimated in 242 GJ ha−1 yr−1. A maximum energy supply of 600 EJ yr−1 could be obtained from the ocean potential area for macroalgae production.