OPTIMIZATION OF SUGAR PRODUCTION FROM SWEET SORGHUM STALKS (BAGASSE) FOR BIOETHANOLPRODUCTION
OPTIMIZATION OF SUGAR PRODUCTION FROM SWEET SORGHUM STALKS (BAGASSE) FOR BIOETHANOLPRODUCTION
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Date
2011-12
Authors
ALEKE, ANN UKAMAKA
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Abstract
Periodic field sampling for reducing sugar content of 14 Sweet Sorghum varieties at 5, 7 and 9
weeks of age were investigated using Dinitro Salicylic acid (DNS) method. Eight sweet sorghum
varieties which comprise 3 Indian: E 36-1, ICSR 93034, SPV 422; 3 Nigerian: SWSV 2006-3,
SWSV 2006-5-2, SWSV 2007-1; and 2 Indian crosses: ICSA 89002 X SPV 422 and ICSA X
NTJ -2 were selected out of fourteen based on the order of increasing reducing sugar content. At
ninth week, ICSA 89002 X SPV 422 had the reducing sugar value of 149.38 ± 1.53mg/ml which
was significantly higher than the other varieties at p<0.05. Two sweet sorghum varieties: SWSV
2006-3 and SPV 422 were subsequently selected from the eight based on field performance,
susceptibility to hydrolysis, % bagasse yield, cellulose, hemicelluloses and lignin content. Two
pretreatment options which include: HCl and H2O2 were then investigated for effective
optimization of glucose yield from the bagasse of two sweet sorghum varieties using glucose
oxidase kit. The results obtained showed that the final optimal concentration and ratio of sample
to pretreatment solution for acid pretreatment are 2%HCl concentrations and 1:50 (ratio of
sample to 2%HCl) respectively for both varieties. At these conditions (2%HCl and 1:50), the
temperature; 121oC released the highest % glucose yield of 15.36 ± 0.51 (from SWSV 2006-3)
which is significantly higher than 10.36 ± 0.51 (of same variety) at 138oC at p<0.05. These
results also revealed that for acid pretreatment, the sweet sorghum variety; SWSV 2006-3
performed better than SPV422 at the temperatures investigated. The optimal concentration and
ratio of sample to pretreatment solution for peroxide pretreatment are 3%H2O2 concentrations
and 1:200 (ratio of sample to 3% H2O2) respectively for both varieties. At these conditions
(3%H2O2 and 1:200), the temperature; 121oC also released the highest % glucose yield of 87.14
± 2.02 (from SPV 422) which is not significantly higher than 85.71 ±0.00 (of same variety) at
138oC (p<0.05). These results also revealed that for peroxide pretreatment, the sweet sorghum
variety; SPV422 performed better than SWSV 2006-3 at the temperatures investigated. H2O2 is a
better pretreatment solution compared to HCl and NaOH. The % glucose yield released from
H2O2 pretreated bagasse showed that 3% H2O2 together with the optimized condition can degrade
cellulose significantly.
Description
A RESEARCH THESIS SUBMITTED TO THE POSTGRADUATE
SCHOOL, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA IN
PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
AWARD OF MASTER DEGREE (M.Sc) IN BIOCHEMISTRY
DEPARTMENT OF BIOCHEMISTRY,
FACULTY OF SCIENCE,
AHMADU BELLO UNIVERSITY,
ZARIA, NIGERIA
DECEMBER, 2011
Keywords
OPTIMIZATION,, SUGAR PRODUCTION,, SWEET,, SORGHUM STALKS (BAGASSE,, BIOETHANOL,, PRODUCTION.