Influence of different pre-treatment routes on the anaerobic digestion of a filamentous algae

The anaerobic digestion of outdoor cultivated Rhizoclonium biomass was investigated in this study. The influence of applying mechanical and biological pre-treatment methods prior to the biomass digestion on the overall methane yields was examined. The results show that the application of a combined biomass blending (<0.1 mm length) and an enzymatic pre-treatment improved the methane yields by >20% compared to use of a mechanical size reduction method alone. The methane yields from Rhizoclonium biomass were however observed to be considerably lower than those of other algae species from the literature.

► CH4 increase (>10%) was seen with ultrasonic pre-treatment of Rhizoclonium samples. ► Enzymatic pre-treatment further improved the CH4 yields by >20%. ► CH4 production from Rhizoclonium was less than other reported microalgae species.