Effects of various dilute acid pretreatments on the biochemical hydrogen production potential of marine macroalgal biomass

This research investigated the effects of various dilute acid (HCl, H 2 SO 4 , HNO 3 , H 3 PO 4 ) pretreatment on the solubilization of marine macroalgal biomass Gelidium amansii and subsequent hydrogen fermentation in a batch vials. The dry grounded biomass was hydrolyzed at temperature of 121 °C, solid/liquid (S/L) ratio of 5% (w/v), dilute acid concentration (1%) of various reagents, and reaction time of 30 min. The hydrolyzates obtained at these conditions were then fed to batch hydrogen fermentation. Results revealed that only H 2 SO 4 pretreatment method had a significant effect on improvement of biohydrogen production from Gelidium amansii , whereas the other pretreatment conditions were even worse than the control experiment. Dilute sulfuric acid (1%) provided a maximum hydrogen production of 52 mL-H 2 /g-dry biomass, whereas control experiment provided a hydrogen efficiency of 27 mL-H 2 /g-dry biomass. The results showed that selection of appropriate pretreatment method is essential for enhanced hydrogen production from macroalgal biomass.