Shegaw, Ahmed (Assoc. Prof.)Daniel, Tesfaye2020-03-072023-11-282020-03-072023-11-282018-06http://etd.aau.edu.et/handle/12345678/20981Leather is a perishable material so it has to be preserved from attack of microorganisms. In leather processing steps, skins can be stored at pickle, wet blue, crust and finished stages. Wet blue preservation is prevents the leather from fungal attack and its commercial carried out using TCMTB based chemicals. This TCMTB based commercial chemicals has adverse effect on human health as well as on aquatic lives. Chlorogenic acid, the major active component of coffee husk, extracted by varying solvent, extraction time and solvent to sample ratio using Soxhlet extractor. Twenty Four extractions were randomly done and results were analysed using Design Expert software version 6.0.8. The extraction procedure using Methanol as solvent, extraction time of 4 hours and 10:1 ratio of sample to solvent resulted as the highest value, which is 681 ppm. The minimum yield (468ppm) was obtained at Ethanol solvent, extraction time of 6 hours and 5:1 ratio of sample to solvent. Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus, Escherichia coli and Aspergillus niger were obtained and tested for the susceptibility and it was found to be Aspergillus niger, a fungi, is more susceptible or sensitive than both gram positive and gram negative bacteria to Chlorogenic acid extracted from coffee husk. The Minimum Inhibitory Concentration (MIC) for Aspergillus niger was found to be 62.5µg/mL. The wet blue preserved using the extracted Chlorogenic acid was tested for its resistance to fungal attack and resist any attack till 15 days. The wet blues were processed to crusting and tested for its strength properties and found to have no change of those properties upon the use of Chlorogenic acid for preservative. The waste water from the process were tested and showed significant minimization of COD and TSS.en-USCoffee HuskChlorogenic acidsusceptibilityWet blueMicroorganismwaste waterMinimum Inhibitory ConcentrationThesis