Recovery of alpha-agarase enzyme from fermentation broths by membrane crossflow filtration

We describe the recovery of extracellular alpha-agarase enzyme from ferment ation broths using a polypropylene hollow fiber filter with 0.5 mu m pores normally used for plasma collection from donors. The permeate flux increase d with inlet wall shear rate from 30 L/h.m(2) at 1500 s(-1) to 45 L/h.m(2) at 3000 s(-1). But the enzyme activity sieving coefficient (ratio of permea te to inlet activity) decreased with increasing shear rate and transmembran e pressure (TMP). Therefore, the enzyme flux transmitted was found to be ma ximum at a shear rate of 1500 s(-1) and a TMP between 20 and 40 kPa. Since enzyme activity decay with time is less at low temperature, the recovered a ctivity was found to be nearly independent of temperature between 5 and 37 degrees C, the maximum occurring at 22 degrees C. The superimposition of fl ow and pressure pulsations on the inlet and outlet lines of the filter with a modified roller pump produced permeate flux enhancements ranging from 44 % at 1000 s(-1) to 68% at 3000 s(-1) for a TMP of 3 kPa.