Dilute acid pretreatment of rice straw at 1% H2SO4 and 160 C
greatly improved the reducing sugar yield and ethanol production
after enzymatic hydrolysis and SSF, respectively. To
maximise ethanol production, it was advantageous to keep
solubilised sugars from the pretreatment hydrolysate with the
pretreated solids and not undergo washing procedures prior
to SSF. This is in contrast to prior studies with cereal straws
suggesting that washing and/or detoxification of pretreated
biomass is imperative for removing compounds inhibitory to
fermentative microorganisms. The highest ethanol yield was
0.20 g g1 [DM] by fermentation with E. coli KO11 on the pretreated
slurry due to its ability to ferment glucose and xylose.
HMF and furfural were present but at low concentrations
which may have higher inhibition on S. cerevisiae D5A than E.
coli KO11 on ethanol fermentation.