Foam Fractionation of Protein with the Presence of Antifoam Agent

• Published in: Separation science and technology Vol. 45; no. 16; pp. 2481 - 2488
• Main Authors: Xu, Zhonghe, Wu, Zhaoliang, Zhao, Yanli
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 01-11-2010
• Subjects: antifoam agent; Cationic; Enrichment; Expenses; foam fractionation; Foams; Fractionation; protein; Proteins; Surfactants
• ISSN: 0149-6395; 1520-5754
• DOI: 10.1080/01496391003674258

Foam fractionation is a promising technology for protein concentration or purification. However, the presence of an antifoam agent in fermentation broth restricted direct application of the technology. A preliminary approach of the surfactant-assisted foam process was conducted with a simulated system consisting of targeted protein bovine serum albumin (BSA), and a mixed antifoam agent (AF520, silicon oil/PGE mixture). The effects of all three classes of surfactants (anionic SDBS, cationic CTAB, and non-ionic Tween-20) on BSA foam fractionation were examined respectively. Also, the influences of solution pH, PGE, BSA, and NaCl were taken into account. The results revealed that all three classes of surfactants could stabilize foam film, so that the foam process could be operated, while the ionic surfactant exhibited excellent performance on condition that it was allowed to firmly interact with BSA to form a more hydrophobic complex, especially for cationic CTAB. When solution pH was adjusted to 7.5 and CTAB was 20 mg · mL
−1
, 90% of BSA could be extracted from a previous non-foaming system containing 100 mg · mL
−1
BSA and 4 mg · mL
−1
AFA, and the enrichment reached 7.42. A higher enrichment of BSA could be obtained with increasing addition of AFA but at the expense of the recovery. On the contrary, increasing BSA concentration gave rise to an opposite performance. The experiments also showed that the foam stability of the system was substantially enhanced by NaCl, significantly lowering the enrichment.