Ethanol production by SHF process
The pretreated young coconut husk pulp
was subjected to an enzymatic hydrolysis to obtain
the monomeric glucose. The combination of two
commercial enzymes, Celluclast 1.5 L and
Novozyme 188, at activities of 15 FPU and 15 IU
per 1 g substrate, respectively, were applied. Five
percent of substrate (w/v) was used. The hydrolysis
reaction was performed at pH 4.8 and 50°C for
72 h with 140 rpm shaking. Subsequently, the
hydrolyzed glucose solution was adjusted to pH
5.5 by the addition of 20 % Ca(OH)2 solution.
Then, this solution was autoclaved at 121°C for
20 min. The ethanol fermentation process was
performed in a total volume of 125 mL using 5
g/L S. cerevisiae cells, 50 g/L glucose, 0.5 g/L
(NH4)HPO4, 0.025 g/L MgSO4.7H2O, 1.2 g/L
NaH2PO4 and 1 g/L yeast extract at 30°C for 72