between the outer surface and the internal structure of the EFB. The internal of the pretreated EFB showed a
clear macrofibril structure compared to the untreated EFB. These microfibrils were separated from the initial
connected structure making the cellulose fully exposed and ready for enzymatic reaction [25, 28]. Later, the
cellulase attacked and broke down the cellulose, causing distortion of fibre and degradation of cellulosic
materials (Fig. 2d), and eventually the cellulose was converted into fermentable sugars, primarily glucose.