Integration and investigation of metal ligands in aqueous two phase extraction and its partition coefficient studies in papain extraction

Abstract

Affinity partitioning in aqueous two phase extraction is a single step purification process in downstream processing. Integrating metal ligands to the phase forming polymers in aqueous phase extraction known as ATPi ensures high selectivity and also promises good partition. In the present work, the effect of metal ligands in aqueous two phase extraction has been studied. This study has been validated in papain enzyme extraction from the fruit latex of papaya (<i>Carica papaya</i><span style="mso-fareast-language:EN-IN;mso-bidi-font-style:italic" lang="EN-US">)<i> </i>and compared with conventional aqueous two phase extraction (ATP). The metal integrated ATPi consisted of 20% w/v polyethylene glycol (PEG) and 15% w/v (NH₄)₂SO₄ along with ligand composition of 0 to 2% w/v of metal ions (CoCl₂, ZnSO₄, CuSO₄, CdCO₃). This was compared with ATP extraction, which was composed of 20% w/v PEG and 15% w/v (NH₄)₂SO₄ without ligands. Purification studies were carried out in anion exchange chromatography. Highly pure papain was obtained from fruit latex of <span style="mso-fareast-language: EN-IN;mso-bidi-font-style:italic" lang="EN-US">papaya<i> </i>using ATPi extraction<i>.</i> The partition coefficient of papain in ATPi extraction was found to be 2.56 times higher than conventional ATP extraction.

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