**4.1 LmPy-GC/MSMS of hand-picked** *Botryococcus braunii* **samples**

The hand-picked *Botryococcus braunii* OWM (organic wall microfossil) was analyzed to check its molecular organic composition. **Figure 9** shows the isolated particles of *Botryococcus braunii* displaying craters generated by the laser radiations and drops of oil yielded. TICs from the LmPy-GC/MSMS analysis showing the distribution of n-alkanes and n-alkenes are shown in **Figure 10**.

To perform LmPy-GC/MSMS analyses on isolated particles (*Botryococcus braunii*), a thermal extraction is necessary (see Section 3.2.2). This extraction aims to release any molecules that may still be adsorbed in the isolated particles, even after performing Soxhlet extraction with DCM in the whole rock. TIC A in **Figure 10** represents the remaining molecules' profile. On the other hand, TICs B, C, and D (**Figure 10**) represent individual analyses of 6–8 particles of *Botryococcus braunii* performed with the goal of confirming the analyses' reproducibility. The n-alkanes and n-alkenes from C8 to C25 were the main pyrolysis products. No cyclic or aromatic compounds were observed.

The experimental results indicated the presence of higher molecular weight n-alkanes, ranging from C25 to C31. These compounds were also identified in the bitumen, as illustrated in **Figure 10A**, suggesting that they were not completely removed in the thermal extraction stage. It is important to note that the presence of aromatic compounds was not detected. This relevant information indicates that the temperature conditions were not severe, avoiding secondary reactions and cleavage of alkyl groups.
