HIGH ETHANOL-PRODUCTION BY NEW ISOLATES OF CLOSTRIDIUM-THERMOCELLUM

Among twelve strains of Clostridium thermocellum isolated from faecal droppings of various herbivorous animals and birds, three of the strai ns, SS21, SS22 and SS19, produced 0.37, 0.33 and 0.32 g of ethanol per g of the substrate consumed and had ethanol to acetate ratios of 2.21 , 2.45 and 1.72 respectively. These are the highest substrate conversi on yields of ethanol amongst the wild strains of C. thermocellum repor ted so far. The optimum temperature and pH for growth and ethanol prod uction were 60 degrees C and 7.5, respectively.