Ethanol production by continuous fermentation of d-(+)-cellobiose, d-(+)-xylose and sugarcane bagasse hydrolysate using the thermoanaerobe Caloramator boliviensis

The recently isolated anaerobic bacterium Caloramator boliviensis with an optimum growth temperature of 60 °C can efficiently convert hexoses and pentoses into ethanol. When fermentations of pure sugars and a pentose-rich sugarcane bagasse hydrolysate were carried out in a packed bed reactor with immobilized cells of C. boliviensis, more than 98% of substrates were converted. Ethanol yields of 0.40–0.46 g/g of sugar were obtained when sugarcane bagasse hydrolysate was fermented. These features reveal interesting properties of C. boliviensis in producing ethanol from a renewable feedstock.