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Good's buffer ionic liquids as relevant phase‐forming components of self‐buffered aqueous biphasic systems
Author(s) -
Taha Mohamed,
Quental Maria V,
e Silva Francisca A,
Capela Emanuel V,
Freire Mara G,
Ventura Sónia PM,
Coutinho João AP
Publication year - 2017
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.5222
Subject(s) - chemistry , ionic liquid , aqueous solution , van der waals force , bovine serum albumin , extraction (chemistry) , hydrogen bond , protonation , aqueous two phase system , dynamic light scattering , inorganic chemistry , chromatography , chemical engineering , molecule , organic chemistry , ion , nanoparticle , catalysis , engineering
BACKGROUND Self‐buffered aqueous biphasic systems (ABS) are prepared with ionic liquids (ILs) based on Good's buffers (GB‐ILs) and used to purify proteins. RESULTS A set of new GB‐ILs based on the tetrabutylphosphonium cation ([P 4444 ] + ) was here synthesized and characterized. The self‐buffering behaviour of the GB‐ILs was asserted by measuring their protonation constants by potentiometry. These ionic liquids display self‐buffering characteristics as well as a low toxicity towards the luminescent bacteria Vibrio fischeri. The ability of the GB‐ILs to form ABS with the potassium citrate salt was investigated. These systems were then evaluated to extract and purify BSA from bovine serum samples. Extraction efficiencies of 100 ± 5% of BSA to the GB‐IL‐rich phase were obtained in a single step. In addition, good recovery yields (59.4 ± 0.8% to 80.1 ± 0.7%), and purity levels of BSA (75.0 ± 0.3% to 92 ± 1%) were also achieved. The BSA secondary structure in the aqueous IL‐rich solutions was evaluated through infrared spectroscopic studies revealing the protein‐friendly nature of the synthesized GB‐ILs. Dynamic light scattering (DLS), ‘Conductor‐like Screening Model for Real Solvents’ (COSMO‐RS), and molecular docking studies were carried out to better understand the main driving forces of the extraction process. CONCLUSION The results obtained show that GB‐IL based ABS can be prepared and used for protein purifications, with the GB‐ILs showing a stabilizing effect on the protein. © 2017 Society of Chemical Industry