The severe effects associated with global warming and the rapid increase in oil prices are the
driving forces behind the demand for clean carbon–neutral and biofuels such as bioethanol.
Research studies are now focusing on using lignocellulosic biomass for bioethanol production due
to concerns about food security and inflation. The chosen feedstock for this study was maize stover,
given that it is the most abundant agricultural residue in South Africa. Maize stover consists of
structural carbohydrates that can be enzymatically converted into fermentable sugars. The major
drawback in the production of bioethanol from lignocellulosic biomass has been its high equipment
and operational costs due to the use of acids and high enzyme loadings. The aim of this study was
to investigate the possibility of optimizing the enzyme hydrolysis of pre–treated maize stover
without further increasing the amount of enzymes. The maximum glucose yield attained was
690 ± 35 mg of glucose per gram of substrate which is equivalent to a conversion efficiency of
119%. The preferred pre–treatment method used was 3% sulphuric acid for 60 minutes at 121oC and
the enzymatic hydrolysis process was performed at a 5% substrate loading, 50oC and pH 5.0 using
30 FPU per gram of cellulose in the presence of 1.25 g.L–1 of Tween 80 for 48 hours. The addition
of Tween 80 increased the glucose yields by 23 % and thus, it has the potential of lowering the
overall process costs by increasing the glucose yield without further addition of enzymes.
Keywords: Bioethanol, maize stover, lignocellulosic biomass, pre–treatment, enzymatic hydrolysis / Thesis (M.Sc. Engineering Sciences (Chemical Engineering))--North-West University, Potchefstroom Campus, 2011.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:nwu/oai:dspace.nwu.ac.za:10394/4852 |
| Date | January 2010 |
| Creators | Mabentsela, Nombongo |
| Publisher | North-West University |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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