Biogas productivity of algal residues from bioethanol production

The purpose of this study was to investigate biogas productivity of algal residues from bioethanol production. Pre-treatment based on enzyme was applied for saccharification to produce bioethanol from the alga, Hydrodictyon reticulatum. Pre-treatment with a combination of enzyme and acid was used for saccharification. The specific methane production yield from raw H. reticulatum, enzyme-saccharified and enzyme/acid-saccharified H. reticulatum residues was 147.6, 408.7, and 537.5 mL CH4/g VS (volatile solids), respectively. The methane yield of raw H. reticulatum from experiment was 22.4 % of the theoretical biochemical methane potential, whereas that of enzyme-saccharified and enzyme/acid-saccharified H. reticulatum residues increased up to 45.8 and 61.4 % of the theoretical value, respectively.