OTR=K4C-C K air,stirrer and speed,viscosity ◆A small gas bubble ◆ C* oxygen carrier temperature and pressure ◆C recom binent DNA OTR=KL a (C*-C) ◆ KL air, stirrer and speed, viscosity ◆ A small gas bubble ◆ C* oxygen carrier temperature and pressure ◆C recombinent DNA