Bio-Ethanol production from sweet Sorghum Stalks grown in varied Agro-Ecological Zones in Africa

Sweet Sorghum is a crop that grows in several parts of Africa. As such, growing and researching the crop in various African countries will promote networking within African Universities especially in the Eastern Africa region. The network has a potential of creating a synergistic approach to issues that cut across African countries such as getting safer, accessible and affordable bioenergy source. Since the project has post project follow up activities, it will also provide an opportunity for prolonged working relationships within African countries and with Austrian partners. This will create a pool of agronomic and bioethanol fuel production experts, deepen working relationships among the project partners and enhance the likelihood of further engagement in the future. This project envisages use of sweet sorghum stalk to produce bio-ethanol for industrial applications, household cooking and lighting. The complexity in processing bio-ethanol fuel from plant residue emanates from difficulty of decomposition of cellulose in the presence of lignin. Lignin is a complex compound surrounding cellulose, which is resistant to enzymatic activities. In majority of regions in Africa where sweet sorghum is grown, the stalks are mostly abandoned in the fields after harvesting of the grains. Thus, the utilization of the stalks for bio-ethanol production will not only eliminate competition between bio-fuel and food but also add value to a waste product and in essence clean the environment. Besides this, the remains, after the juice is extracted from the stalk, are used as organic manure to improve soil fertility. Given ready availability of these materials and their affordability, the bio-fuel that will be produced by the project will be relatively cheaper than the fossil based fuels in terms of cost and long term environmental conservation. The ethanol produced is highly stabilized to have high calorific value of 4.96 kcal/g against that of wood fuel at 3.22, making it a suitable cooking energy. Another critical advantage of the bio-fuel to be produced is its ability to blend which makes it burn longer. The bio-fuel can be purified through removal of impurities; it becomes environmentally safer since it produces less greenhouse gases during combustion compared to the fossil based fuels. With tons of plant residue of sorghum in agricultural fields, there is a huge potential in providing affordable and clean energy to the local population. This study aims to produce bio-ethanol from sweet sorghum stalk that is grown in different parts of Africa. The work will establish the optimum agronomic conditions for varieties of sweet sorghum in different agro-ecological zones (AEZ) in Africa (Ethiopia, Kenya and Uganda). It will be achieved by identifying the different cultivars grown in the selected countries (agro ecological zones); characterize the Soil Crop Atmospheric parameters (for example soil: fertility, pH, physical properties-texture among others) suitable for production in each AEZ. Based on this, promising cultivars will be grown in the AEZs. The stalks from the best cultivar can be subjected to chemical processes, including the brix levels determinations, in order to determine the optimum conditions for bio-ethanol production at laboratory scale. The best sweet sorghum cultivar in terms of brix levels will be selected for bulk production of planting materials. Quality testing and characterization of the bio-ethanol will be done while considering chemical composition, calorific value, alcohol content, moisture content, ash content, flash point, specific gravity, sulfur content and total solid content in order to compare it with existing cooking fuels. The study findings will be of importance considering that the bio-ethanol produced at the laboratory scale and best sweet sorghum cultivars can be up scaled to meet not only the food needs (grains) of most rural African communities but their energy and industrial needs (stalks) as well.