Lipase production and purification by self- buffering ionic liquid-based aqueous biphasic systems

In this work, a group of Good’s buffer ionic liquids (GB-ILs) comprised of tetrabutylammonium, tetrabutylphosphonium and cholinium cations paired with Good’s buffer (GB) anions (MOPSO, BES and TAPSO) was studied. Their distinctive capability to induce the formation of aqueous biphasic systems (ABS) with the salts K3PO4, K2CO3, and (NH4)2SO4, and the polymers poly(ethylene glycol) (PEG), poly(propylene glycol) (PPG), and PEG-PPG copolymers was demonstrated. Their application as purification tools to recover a lipase produced via submerged fermentation by Burkholderia cepacia ST8 was investigated. The lipase was preferentially partitioned towards the GB-IL-rich phase in both the GB-IL + salt and polymer + GB-IL purification systems. Molecular docking studies were performed aiming at to understand the possible interactions between the GB-IL ions and the lipase residues. Furthermore, the selected GB-IL-based ABS was investigated as part of an integrated process developed to successfully recover and purify an extracellular B. cepacia ST8 lipase from the fermentation broth, in which a purification factor of 22.4 ± 0.7 and a recovery yield of (94.0 ± 0.2) % were achieved.