초록
This study investigated the hydrogen fermentation in a two-stage combined fermentation process (combination of dark fermentation for hydrogen (H<SUB>2</SUB>) production from microalgae and methane (CH<SUB>4</SUB>) fermentation from residues following H<SUB>2</SUB> production process). Microalgae Chlorella vulgaris culture was used as a substrate. The hydrogen production from C. vulgaris ranges 1.75+/-1.50-19+/-2.94ml H<SUB>2</SUB> g-VS<SUP>-1</SUP> at different substrate dosages without enzymatic pre-treatment. A seven-fold increase in H<SUB>2</SUB> production yields (19+/-2.94-135+/-3.11ml H<SUB>2</SUB> g-VS<SUP>-1</SUP>) was observed with enzymatic pre-treatment (Onozuka R-10 and Macerozyme R-10) of the microalgae. The results of the CH<SUB>4</SUB> fermentation show that the methane yields could be increased from 245+/-2.46 to 414+/-2.45ml CH<SUB>4</SUB> g-VS<SUP>-1</SUP> by using enzymatic pretreatment. In addition, the yield of the CH<SUB>4</SUB> fermentation (14.86kJ/g-VS) has approximately the same order of magnitude in comparison to the two-stage combined fermentation process (14.46kJ/g-VS) in terms of energy production.