Preliminary application of light-pH sensitive recycling aqueous two-phase systems to purification of lipase

One key problem of aqueous two-phase systems (ATPS) is that phase-forming polymers could not be recycled efficiently. This results in high cost and environmental pollution. In this study, we introduced novel aqueous two-phase systems which are composed by pH-sensitive polymer PADB and light-sensitive polymer PNNC. PNNC is enriched in the top phase while PADB is found in the bottom phase. And recoveries of two-phase-forming polymers can both reach over 96%. This aqueous two-phase system was used for purification of lipase from its crude material. The influences of various process parameters such as concentration of the phase-forming polymer, system pH, different types and concentrations of neutral salts on partitioning of lipase are evaluated. It has been found that partition coefficient of pure lipase could reach 0.061 under optimized conditions. Lipase from crude material was purified with 83.7% recovery and a purification factor of approximately 18 folds.