Abstract:
This study suggests a new effective chemical pretre
atment to hydrolyze rice straw for
efficient ethanol production. It introduces a new y
east strain that ferments rice straw
hydrolyzate more efficiently than
Saccharomyces cerevisiae
. The results proved the
effectiveness of alkali application before HCl to d
elignify rice straw and to make it more
appropriate for hydrolysis. The application of the
hydrolyzing enzymes (cellulase and
pectinase) resulted in hydrolysis of pretreated ric
e straw up to 94.3%
. The total sugars
released due to pretreatment-enzyme system was abou
t 624 mg g
–1
dry mass and the
glucose fraction was 198 mg g
–1
. The results indicated that
Pichia guilliermondii
is more
effective to ferment rice straw hydrolyzate than
S. cerevisiae
.
P. guilliermondii
produced
larger amounts of bioethanol (7.72 g L
–1
) than
S. cerevisiae
(6.13 g L
–1
)
under the same
conditions. Our results suggest an appropriate pret
reatment system (the cold dilute
alkali-acid) and a new effective yeast strain to fe
rment the rice straw hydrolyzate to
produce large amounts of bioethanol.
Keywords:
Bioethanol, Hydrolysis
,
Pretreatment
, Pichia guilliermondii,
Rice straw,
Saccharomyces cerevisiae
.
