1. UKM Learning and Research Repository
2. PHD Thesis / Tesis PHD
3. Faculty of Science and Technology / Fakulti Sains dan Teknologi

Title:	Whole value chain for production of bioethanol from sorgum straw as the raw material for carbon source
Authors:	Elmubarak Musa Tibin Musa (P50296)
Supervisor:	Wan Mohtar Wan Yusoff, Prof. Dr.
Keywords:	Lignocellulosic feedstock Bioethanol Substrate Universiti Kebangsaan Malaysia -- Dissertations
Issue Date:	10-Nov-2017
Description:	Unstable oil markets with rising environmental concerns have revived widespread interest in production of bioethanol from renewable materials. The aim of this study was to efficiently use sorghum (Sorghum bicolor) straw as a lignocellulosic feedstock for bioethanol production. The sorghum straw was used as the raw material for production of reducing sugar by fermentation of Aspergillus terreus SUK-1, then the reducing sugar was subsequently used as carbon source for production of bioethanol by S Cerevisiae. Four sorghum varieties (Fatareeta, Hageen, Tabat and Gadamalhamam) imported from Sudan were successfully planted in Malaysia. Hageen is the best variety in term of straw weight (4.00 ± 0.00 Kg/m2. 90 days). Results obtained from approximate analysis for straw of Hageen variety showed that sorghum straw has a highest amount of carbohydrate (83.30 ±1.60 g/100g). Study was carried out for cellulase (FPase and CMCase) production using Aspergillus terreus SUK-1. The process parameters for maximizing FPase activity were as follows; inoculum size 10% v/v, substrate particle size of 1 mm and incubation period of 6 days. Further optimization of process parameters that included initial pH, incubation temperature and moisture content by RSM-CCD showed that the optimum conditions for maximum FPase activity were as follow; temperature 33.45˚C, pH 5.27 and moisture content 53%. The parameters maximized CMCase activity were; 33.80˚C, pH 5.35 and moisture content. 64% Medium formulated for enhanced cellulase production was optimized using empirical models including Plackett-Burman design followed by response surface methodology (RSM) with central composite design (CCD). The optimized medium improved the production of FPase at 3.96 U/mL which was in agreement with the predicted value (3.68 U/mL). The optimum parameters for maximum sugar concentration using RSM-CCD by hydrolysis of sorghum straw were; pH 5.53, temperature 43.27˚C and substrate concentration 4.85%. The maximum sugar concentration was obtained with cellulase enzyme dosage of 10.03 FPase/g substrate. Hydrolysis of Sorghum straw under optimized hydrolysis conditions produced 41.0 g/L of fermentable sugars. Parameters involved in bioethanol fermentation by Saccharomyces cerevisiae were studied. Ammonium sulphate was found to be the best nitrogen source. Treatment with activated charcoal for sorghum straw hydrolysates enhanced the production of bioethanol in terms of concentration, yield and productivity from 8.1g/L, 0.203 g/g and 0.17 g/L.h, respectively to 9.2 g/L, 0.229 g/g and 0.19 g/L.h, respectively. Enhanced bioethanol fermentation by Saccharomyces cerevisiae showed the following best operating conditions: initial pH 4, inoculum size 10%, incubation temperature of 30˚C and 48h incubation period. Studies in 5L bioreactors under the above optimized conditions produced 10.5 g/L bioethanol with yield of 0.037 g/g and productivity of 0.218 g/L.h. As a conclusion, sorghum straw was established as a potential substrate for bioethanol production.,Certification of Master's/Doctoral Thesis" is not available
Pages:	194
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.