FIG. 3.

Continuous system for harvesting, concentration, and desalting of proteins in the supernatants of fermentation broth of P. alcaligenes strain DIP1 (phase II). For harvesting, a CEPA Z41 continuous centrifuge was used to separate the cells from the medium. The supernatant was collected in a central 100-liter tank. For concentration, a cross-flow unit with a 30-kDa cassette was connected to the central tank; the concentrated retentate was pumped back into the tank, while the permeant material was directly discarded. The flow rate of the cross flow was adjusted to maintain only 50 liters in the tank. The final concentrated enzyme solution of 5 liters was desalted with 5 bed volumes of H₂O, frozen at −30°C, and lyophilized.