Immobilization of Candida antarctica Lipase B on Porous Polystyrene Resins: Protein Distribution and Activity

Abstract

We studied the effects of polystyrene resin particle size and pore diameter on Candida antarctica Lipase B (CALB). CALB adsorbs rapidly on polystyrene (saturation time ≤ 4 min) for particle sizes ≤ 120 μm (pore size 300 A). Through infrared microspectroscopy, CALB was shown to form protein loading fronts regardless of resin particle size at similar enzyme loadings (∼ 8%). From IR images, fractions of total surface area available to enzyme are 21, 33, 35, 37 and 88%, respectively, for particle sizes 350-600, 120, 75, 35 μm (pore size 300 A) and 35 μm (pore size 1000 A). Titration with p-nitrophenyl n-hexyl-phosphate (MNPHP) showed the fraction of active CALB molecules adsorbed onto resins was about 60 %. The fraction of active CALB molecules was invariable as a function of resin particle and pore size. At about 8% w/w CALB loading, by increasing the immobilization support pore diameter from 300 to 1000 A, turnover frequency (TOF) of e-CL to polyester increased from 12.4 to 28.2 S -1 . However, the e-CL conversion rate was not influenced by changes in resin particle size. Similar trends were observed for condensation polymerizations between 1,8-octanediol and adipic acid.