Kinetics of methane production from the codigestion of switchgrass and Spirulina platensis algae

► Methane yields of Spirulina platensis were almost the same at 35 and 50 °C after 40 days of digestion. ► Strong negative correlations between gas yields and the portion of switchgrass in the feed were determined. ► There was no significant synergic or antagonistic effect of the co-digestion of S. platensis and switchgrass. ► The Cone model best described the data while the exponential model was the worst predictor of the experimental data.