Partial Purification of Polyphenol Oxidase (PPO) from Mango Seed Kernel (MSK) using Alcohol/Salt-based Aqueous Two-Phase System (ATPS)

Polyphenol oxidase (PPO) has applications in pharmaceutical, environmental, and food industries, however, conventional techniques for its purification are considered costly and laborious. Alternative methods of purification are needed. This study explored the use of an alcohol/salt-based aqueous two-phase system (ATPS) to partially purify PPO from mango seed kernel (MSK). Specifically, this study determined the effects of 1-propanol/potassium phosphate buffer mass ratio on the partition parameters such as partition coefficients, activity recovery, and purification fold. The enzyme partition coefficient (K E ) was greater than 1, which signified that more PPO was partitioned in the top phase due to its hydrophobic nature. Specifically, the 3.22 1-propanol/PPB mass ratio had the highest K E of 1.91 ± 0.16 and 1.46 ± 0.16 for runs 1 and 2, respectively. Moreover, the same mass ratio led to the highest activity recovery in the top phase reaching up to 73.99 ± 1.56% for run 1 and 64.27 ± 2.48% for run 2. In terms of purification fold, runs 1 and 2 had PF values of 0.55 ± 0.05 and 0.70 ± 0.01, respectively. Since the values obtained were low due to the large number of contaminants extracted together with the target enzyme in the top phase, the use of a back-extraction step recovered the PPO in the bottom phase and resulted in an activity recovery of 82.94 ± 1.05% and a purification fold of 7.01 ± 0.95. Results have shown that varying the mass ratio had significant effects on the partition parameters.