production from Sorghum bicolor using both separate
and simultaneous saccharification and fermentation in batch
and fed batch systems
Sajid Mehmood1,3, Muhammad Gulfraz1*,
Nosheen Fatima Rana1, Asif Ahmad1,
Brigitte Kiær Ahring2, Nasir Minhas1
and Muhammad Faheem Malik3
of Biochemistry, PMAS Arid Agriculture University
Rawalpindi, Murree Road, Rawalpindi 46300 Pakistan.
and Technology (BST), Biocentrum –DTU, Technical University
of Denmark, 2800 Lyngby, Denmark.
of Gujrat, Hafiz Hayat Campus, Gujrat, Pakistan.
*Corresponding author. E-mail:
email@example.com. Tel.: +92519062268.
Accepted 20 March, 2009
The objective of this work was to find the best combination
of different experimental conditions during pre-treatment,
enzymatic saccharification, detoxification of inhibitors and
fermentation of Sorghum bicolor straw for ethanol
production. The optimization of pre-treatment using
different concentrations of dilute sulfuric acid, various
temperatures and residence times was achieved at 121°C, 1%
acid concentration, 60 min residence time and enzyme
saccharification using cellulase (celluclast 1.5 L) and β-glucosidase
(Novozyme 188) at 50°C and pH 4.8 for 48 h. Different
surfactants were used in order to increase the monomeric
sugar during enzymatic hydrolysis and it has been observed
that the addition of these surfactants contributed
significantly in cellulosic conversion but no effect was
shown on hemicellulosic hydrolysis. Fermentability of
hydrolyzate was tested using Saccharomyces cerevisiae
Ethanol RedTM and it was observed that
simultaneous saccharification and fermentation (SSF) with
both batch and fed batch resulted in better ethanol yield as
compared to separate hydrolysis and fermentation (SHF).
Detoxification of furan during SHF facilitated reduction in
fermentation time from 96 to 48 h. 98.5% theoretical yield
was achieved in SHF with detoxification experiment attaining
an ethanol concentration and yield of 23.01 gL-1
and 0.115 gg-1 DM respectively. During the SSF
batch and fed batch fermentation, the maximum yields of
ethanol per gram of dry matter were 0.1257 and 0.1332 g
Sorghum bicolor, ethanol, separate hydrolysis and
fermentation (SHF), simultaneous saccharification and
fermentation (SSF), furfural and hydroxymethyl furfural,
surfactant, batch and fed batch fermentation.