Karnika Ratanapongleka

pp. 69 - 76

Abstract

In the present study, an aqueous two phase system (ATPS) composed of polyethylene glycol (PEG) and potassium
phosphate was employed to purify laccase produced by Lentinus polychrous. The assessments of system parameters such as
molecular weight of the PEG, PEG concentration, phosphate salt, system pH, and neutral salt (NaCl) concentration on laccase
partitioning and purification were investigated. The enzyme preferentially partitioned in the top polymer-rich phase in all
tested systems. Desirable conditions for partitioning were found in the system having polyethylene glycol of intermediate
molecular weight 4,000. This work revealed that the extraction efficiency was not much affected by PEG concentration. The
NaCl addition decreased greatly the partition coefficient of laccase. The optimal system was obtained at pH 7.0, containing
12% w/w PEG 4,000 and 16% w/w potassium phosphate with enzyme partition coefficient of 88.30, purification factor of 3.01-
fold, and 99.08% yield of enzyme activity in the top phase. Overall, the results obtained in this study revealed that ATPSs
could be potentially useful technique for a first step purification of laccase from L. polychrous.