Fig. 3
Scanning election microscopy (SEM) images of raw PH (a), H3PO4/H2O2-pretreated PH (b), popping-pretreated PH (c), and HPAC-pretreated PH (d). c, d were cited from our previous work [22], and were permitted to be used here
Fig. 3 | Biotechnology for Biofuels