Only one reaction time was checked. Due to the small size of microalgae, the selected reaction time (5 min) is enough to reach homogeneity in temperature. This homogeneity is assumed to provide a proper and smooth explosion. After reaction, the exploded samples were collected for further analysis. Table 2 shows the specific experimental conditions, i.e. temperature, time and acid concentration at impregnation and at reaction, used for each steam explosion experiment.