Keywords: coffee cherry husk, CCH, Pichia, Clavispora, fermentation, feedstock, alcohol production, yeast isolates, coffee effluent, coffee pulp, coffee fruit peel
Coffee cherry husk (CCH) a toxic agro waste was tested for alcohol production by native yeast isolates. Out of five isolated yeasts, two produced acceptable amount of alcohol production from CCH extract. Pichia CJ isolated from rotten carrot and Clavispora CI isolated from coffee effluent produced maximum yield of 9.2 and 8.0%, respectively. Solid substrate fermentation (SSF) using CCH supported higher percentage of alcohol compared to submerged fermentation (SmF). Maximum alcohol yield was achieved at 100 gm/600 ml dilution (w/v, husk: water). Optimum pH and temperature were found to be in the range of 4–4.5 and 25–30°C respectively for maximum alcohol production. Experiments with coffee pulp and coffee fruit peel yielded lower concentrations of alcohol when compared to CCH.