Ethanol Tolerant Anaerobic Cellulolytic Ethanologenic Bacteria Isolated from Decomposed Paper

Ethanol tolerant anaerobic cellulolytic bacteria were isolated from decomposed paper. The better ethanol tolerant isolate MD2 was characterized and identified as Clostridium sp. based on morphological, cultural and biochemical characterization following standard methods. The major fermentation products were ethanol and small amounts of acetic acid and CO₂. The optimum fermentation conditions observed for maximum ethanol production and substrate degradation were 40°C, pH 7.5 and 5% innoculum and the isolate was found to be ethanol tolerant to 3% ethanol. Selected untreated and pre-treated cellulosic agro-wastes supported growth and ethanol production by MD2. Maximum ethanol yield of 0.269 (g/g) was obtained with alkali treated banana leaves and pseudostem and 0.225 (g/g) with avicel. This is also the first report on ethanol tolerant mesophilic Clostridium sp. for single step conversion of banana waste to ethanol.