Abstract: The biotransformation of adenosine to ATP using immobilized saccharamyces cerivisae in multifunctional shake flask of Y Z type was studied and the process parameter curves were obtained. When the same process was scaled up into a liquid recycling fluidized bed reactor, it was found that of the time course profile of carbon dioxide evolution rates( CER ) was maintained identically with that obtained from sake flask test same conversion results could be obtained as that from shake flask test. So the CER can be considered as a sound scale up criterion of this biotransformation process.