Bioenergy Science and Technology
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Item CHARACTERIZATION AND EVALUATION OF BANANA PSEUDO-STEMS FOR BIOETHANOL PRODUCTION(Hawassa University College of Agriculture, 2022) TEMESGEN AYELE ADEBio-fuels like bioethanol originated from lignocellulosic biomasses are being investigated as potential substitutes for current high pollutant fuels obtained from conventional sources. Banana pseudo-stem is one of lignocellulosic biomass, which is generated from banana cultivation. This study was carried out to Characterize and Evaluate Banana Pseudo-stems for Bioethanol Production. For this study, Giant Cavendishii (M. acuminata), Dwarf Cavendishii (M. acuminata), and William-1 (M. ‘Williams hybrid’) banana pseudo-stems were used for investigation. In this study, chemical compositions of pseudo-stems (extractives, cellulose, hemicellulose, lignin, and ash) were determined through National Renewable Energy Laboratory (NREL) protocol. Bioethanol was also produced from each pseudo-stem through biochemical conversion method. The production method had four major processes; pseudo-stem pretreatment, hydrolysis, fermentation, and distillation. Some of the physicochemical properties of produced bioethanol (Viscosity, Density, Flash point, Alcohol concentration, and Calorific value) were tested. The functional group of the produced bioethanol was analyzed using Fourier Transform Infrared (FTIR) spectroscopy. And finally, bioethanol yield of each variety was determined depending on the concentration of produced bioethanol. Each laboratory experiments were conducted for triplicate. The data analysis of experimental result was done by using statistical analysis of variance (one way ANOVA), through statistical analysis software (SAS). The laboratory result of extractives, cellulose, hemicellulose, lignin, and ash content of the pseudo-stems were 27.25% - 31.15%, 30.11% - 36.14%, 19.32% - 23.83%, 8.81% - 9.30%, and 7.99% - 9.30%, respectively. And bioethanol yield of Giant Cavendishii, Dwarf Cavendishii, and William-1 pseudo-stem were 6.31%, 5.20%, and 4.00%, respectively. The statistical analysis software (SAS) output implied that the pseudo-stems of the three varieties have significantly different cellulose composition and bioethanol yield. As the result implied, pseudo-stem of giant cavendishii (M. acuminate) has the largest cellulose content and bioethanol yield followed by dwarf cavendishii (M. acuminata). Thus, giant cavendishii (M. acuminate) has relatively higher bioethanol potential. Therefore, giant cavendishii banana pseudo-stem is recommended to use as feedstock for bioethanol production.Item EVALUATION OF SEDGE GRASS (S. tabernaemotani) FOR BIOETHANOL PRODUCTION(Hawassa University College of Agriculture, 2021) FREWEYNI HAILUBiofuel production from first generation biomasses, basically human food, might lead to problem of food crisis. Non-edible lignocellulosic biomass which is abundant with low production cost would be considered as an appropriate feedstock for ethanol production. Sedge grass (Schoenoplectus tabernaemontani) is one of environmental friendly non-edible lignocellulosic grasses.However; there are no reports on the use of sedge grass for bioethanol production. Therefore, this study was conducted to investigate the yield of total reducing sugar from sedge grass for ethanol production, with three levels of hydrolysis time (40, 60 and 80 min), three levels of H2SO4 concentration (1.5, 2.5 and 3.5%) and three levels of temperature (115, 125 and 135oC) designed in Complete Randomized Design (CRD) with three replications. The chemical compositions (extractives, cellulose, hemicellulose and lignin) of the plant were also determined by using National Renewable Energy Laboratory (NREL) protocol. The reducing sugar yield was determined by Benedict’s solution using spectrophotometer. Simple distillation was carried out to separate ethanol from water and the functional group of the produced ethanol was analyzed using Fourier Transform Infrared (FTIR).To estimate the ethanol yield, potassium dichromate method was used. As the result indicated, the content of hemicellulose, cellulose, lignin and extractives were 42%, 39.87%, 13.07% and 5.06%, respectively. The two-way interaction of treatments exhibited significant differences on total reducing sugar yield. Concerning the three-way interaction, highest total reducing sugar was produced when the feedstock was hydrolyzed at a temperature of 1250C for 60 min by 2.5% dilute H2SO4 solution. However, the lower percent of total reducing sugar yield (38.29%) was recorded from hydrolyzed sample at a temperature of 1350c for 80min using 3.5% dilute H2SO4 solution. Eventually, the highest ethanol yield (51.02%) was recorded from 49.83% of hydrolyzed sample reducing sugar fermented by F. oxysporum for 7 days fermentation. Therefore, sedge grass biomass is recommended as raw materials for bioethanol production, which is a promising alternative energy source against the depleting petroleum.