1. School of Chemical Engineering, Jimma Institute of Technology, Jimma University, Jimma, P.O. Box 387, Ethiopia
2. Department of Chemical Engineering, College of Biological and Chemical Engineering, Addis Ababa Science and Technology University, Addis Ababa, P.O. Box 16417, Ethiopia
3. Central Laboratory, Research and Technology Transfer, Addis Ababa Science and Technology University, Addis Ababa, P.O. Box 16417, Ethiopia