and the pH of the hydrolysis tanks was automatically controlled using an acid or a base. After completing hydrolysis and fermentation, the fermented mash was transported to a buffer tank using a pump.
A separate hydrolysis and fermentation (SHF) process was used to produce ethanol from EFB for this study. Enzymatic hydrolysis of pretreated EFB fibers was conducted in accordance with the standard National Renewable Energy Laboratory (NREL) procedure for chemical analysis and testing [14]. Operating conditions were 50 °C, pH 4.8 (controlled using sulfuric acid), and agitation at 60 Hz. The enzyme loading amounts were 40 FPU/g cellulose (Cellic® CTec 2) and 15% Cellic® HTec 2 (this value was based on the amount of Cellic® CTec 2 loaded into the mixture). Enzymatic hydrolysis was performed once two batches of the pretreated mixture were collected. After saccharification, the sample was transferred to the fermentation tanks and fermented with 5% Saccharomyces cerevisiae at 33 °C for 48 h.