STABILITY OF UREASE DURING AEROSOLIZATION - THE EFFECT OF OPERATING-CONDITIONS

The stability of the enzyme urease to the aerosolization process was e valuated. The effect of liquid feed rate, operating pressure, gas comp osition and relative humidity on urease enzymatic activity were studie d using a Constant Output Atomizer operated in the non-recirculating ( i.e. single-pass) mode. The results show that changes in the liquid fe ed rate had the greatest influence on subsequent urease enzymatic acti vity. Relative humidity of the supply gas also played an important rol e through its influence on solution evaporation rate and resultant pro tein concentration in the solution. Operating pressure and gas composi tion had only minor effects. Additional experiments run with a Colliso n nebulizer operating in the recirculating (multi-pass) mode indicated a time-dependent loss of urease activity. On average, 50% of the init ial activity was left in the nebulizer solution after 10 min of operat ion. The introduction of protective additives to the solution helped t o reduce degradation. (C) 1998 Elsevier Science Ltd. All rights reserv ed.