2.4. Saccharification and fermentation tests
SSF (simultaneous saccharification and fermentation) and SHF
(separate hydrolysis and fermentation) experiments were carried
out according to the pretreatment and presaccharification conditions
described above. In the SSF and SHF assays, flasks were inoculated
with yeast cultures using the following presaccharification
conditions: 0, 24 or 72 h at 37, 42 or 50 C. The fermentation was
initiated by adding yeast culture to an OD600nm of 2. SSF assays
were conducted under sterile conditions at 37 or 42 C for 24 h.
Samples were collected every 2 h and centrifuged for 15 min at
10,000g. The supernatants were used to quantify carbohydrates
and ethanol by HPLC. In the SHF assays the supernatants of hydrolysis
were separated from biomass by centrifuging prior the yeast
inoculation.