EXTRACTION OF ALPHA-CHYMOTRYPSIN USING REVERSED MICELLES

Liquid-liquid extraction of α-chymotrypsin into an organic phase containing a quaternary ammonium salt (Aliquat 336) dissolved in esters or in isooctane by means of isotridecanol has been investigated. The partitioning of α-chymotrypsin between the organic and the aqueous phases depends on the parameters of both phases. The protein is most significantly extracted above its isoelectric point, when negatively charged and at low ionic strength. The extraction performance is maximum in isooctane for 1% v/v isotridecanol concentration and increases when the Aliquat concentration increases. For 0.1 M Aliquat concentration in isopropylmyristate, 90% of α-chymotrypsin is extracted in the organic phase. The existence of monodisperse reversed micelles in isooctane was checked by quasi-elastic light scattering measurements and the hydrodynamic radius of the droplets was determined at about r = 22 A ̊. For esters, which are more polar solvents, the hypothesis of a polydisperse population of micelles is proposed in order to explain the experimental results. © 1990.