Sulfolobus solfataricus used 2-propanol and 2-propanone (acetone) when grown in static cultures at 78 °C with or without glucose at 10 g l-1. The presence of 3.92 g 2-propanol l-1 in both cases inhibited growth. However, acetone accumulation following 2-propanol depletion suggested that 2-propanol was co-metabolized via the acetone metabolic pathway. Glucose at 10 g l-1 increased 2-propanol and acetone utilization from 0.93 g l-1 to 1.77 g l-1 and from 0.11 g l-1 to 1.62 g l-1, respectively. Without glucose, immobilized S. solfataricus cells increased the 2-propanol removal rate to 0.035 g l-1 h-1, compared to 0.0012 g l-1 h-1 by its suspended counterpart. The results suggest the establishment of an immobilized reactor configuration is preferential for the treatment of high temperature solvent waste streams by this acidothermophilic Crenarchaeon.