초록
<P><B>Abstract</B></P> <P>In the pursuit of renewable sources for biogas generation, microalgae biomass constitutes a promising alternative. In this work, thermally pretreated <I>Scenedesmus obtusiusculus</I> was evaluated as source of biomass for methane production, in systems operated under batch and semi-batch regime. In batch experiments, methane production yields ranging from 109.3 to 192.7 mL CH<SUB>4</SUB>/g VS<SUB>added</SUB> were observed with thermally-pretreated (98 °C, 6 h) microalgae biomass at concentrations between 1 and 10 g tCOD/L. On the other hand, the system operated under semi-batch mode for 50 days attained a volumetric methane production rate of 1.15 L CH<SUB>4</SUB>/L-d with a methane yield of 177.9 mL CH<SUB>4</SUB>/g VS<SUB>added</SUB> at an organic loading rate of 10 g tCOD/L-d and a reaction time of 12 h. These results demonstrate that methane production from microalgae biomass in a semi-batch reactor is possible at low reaction time (12 h) and high organic loading rate using a moderate-temperature pretreatment for the microalgae biomass.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Thermal pretreatment of <I>S. obtusiusculus</I> improves methane production yields. </LI> <LI> Highest biomass solubilization was achieved for pretreatment at 98 °C and 6 h. </LI> <LI> Pretreated biomass increased methane production rate almost 2-fold in batch mode. </LI> <LI> High semi-batch methane production was feasible at low RT (12 h) and high OLR. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>