Improved Economics of Extractive Enzyme Recovery by Recycling: A Case Study
A wide variety of enzymes and other biologically active proteins have been isolated by aqueous phase extraction  and the technology is already applied in industry. The technique has several advantages; a drawback is the relatively high consumption of chemicals to form the aqueous phases which becomes significant in large scale production. The economics of recovery, however, may be improved by reusing the phase-forming chemicals as has already been demonstrated in batch  and also in continuous operation with batchwise recycling . We have also been investigating the feasibility of continuous recycling and some results are presented here. The isolation of the enzyme fumarase from S. cerevisiae was adopted as a model. The separation was carried out continuously in a phase system comprising PEG (MW 1500) and potassium phosphate in 2 consecutive stages, a first stage which removes cell debris, DNA and other proteins, and a second stage for the further purification of the enzyme and the recovery of PEG . The isolation was carried out in a computerised pilot-scale plant with a capacity of approximately 100 1/h total liquid throughput or 150 tonnes per annum wet cell mass. The phases were separated by centrifugal separators of type SA-1 (E-factor of 1460 m2) (Westfalia Separator AG, Oelde, FRG) see . The top (PEG-rich) phase from the second stage was recycled continuously to the first stage  while monitoring the protein and enzyme levels automatically in 3 streams.
KeywordsPotassium Phosphate Utility Cost Remove Cell Debris Consecutive Stage Centrifugal Separator
Unable to display preview. Download preview PDF.
- 3.H. Hustedt, unpublished resultsGoogle Scholar
- 4.H. Hustedt, K.H. Kroner and N. Papamichael, in: “Separations Using Aqueous Phase Systems: Applications in Cell Biology and Biotechnology,” D. Fisher and I.A. Sutherland, eds., Plenum, New York (1989)Google Scholar
- 5.K.H. Kroner, H. Hustedt and M.-R. Kula, Proc. Biochem. 19:170 (1984)Google Scholar