In situ purification of periplasmatic L-asparaginase by aqueous two phase systems with ionic liquids (ILs) as adjuvants


BACKGROUNDL-asparaginase (ASNase) is an important biopharmaceutical used to treat the acute lymphoblastic leukemia (ALL) and lymphosarcoma. Considering its main use in cancer therapy, the most important request for ASNase production is the need for a highly pure biopharmaceutical obtained in the final of the downstream process, which is considered as the crucial step in its production. RESULTSThis work proposes the use of polymer-salt aqueous two-phase systems (ATPS) based on polyethylene glycol and citrate buffer, with ionic liquids (ILs) as adjuvants, combined with the permeabilization of cell membrane using n-dodecane and glycine for the in situ purification of periplasmatic ASNase from Escherichia coli cells. The process proposed was optimized (polymer molecular weight, pH, tie-line length/mixture point, presence, nature and concentration of the adjuvant). The results show that ASNase partitions mostly to the PEG-rich phase, due to hydrophobic interactions between both PEG and enzyme. Remarkably, the addition of 5wt% of 1-butyl-3-methylimidazolium methanesulfonate [C(4)mim][CH3SO3] as adjuvant lead to high recoveries [87.940.03 (%)], purification factors (20.09 +/- 0.35), and a final specific activity SA=3.61 +/- 0.38U mg(-1) protein, from a crude enzyme extract with a SA=0.18 +/- 0.05U mg(-1) protein. Moreover, better results were achieved when a prepurification step consisting of an ammonium sulfate precipitation was combined with the optimized ATPS, achieving an increased SA=22.01 +/- 1.36U mg(-1) protein and PF=173.8. CONCLUSIONSA novel integrated downstream process was successfully implemented for the in situ purification of ASNase from fermentation broth. (c) 2017 Society of Chemical Industry




Biotechnology & Applied Microbiology; Chemistry; Engineering


Santos, JHPM; Flores-Santos, JC; Meneguetti, GP; Rangel-Yagui, CO; Coutinho, JAP; Vitolo, M; Ventura, SPM; Pessoa, A

nossos autores


This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. The authors are grateful for the financial support of Portuguese Foundation for Science and Technology (FCT) for the doctoral grant SFRH/BD/102915/2014 of Joao H. P. M. Santos. S.P.M. Ventura acknowledges FCT/MEC for a contract under Investigador FCT 2015 contract number IF/00402/2015. The authors also thank FAPESP (Sao Paulo Research Foundation, Brazil) for the financial support through the project process 2013/08617-7 and CNPq (National Council for Scientific and technological Development, Brazil).

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