Immobilization of Yarrowia lipolytica Lipase—a Comparison of Stability of PhysicalAdsorption and Covalent Attachment Techniques

摘要

Lipase immobilization offers unique advantages in terms of better process control,enhanced stability, predictable decay rates and improved economics. This work evaluated theimmobilization of a highly active Yarrowia lipolytica lipase (YLL) by physical adsorption andcovalent attachment. The enzyme was adsorbed on octyl–agarose and octadecyl–sepabeadssupports by hydrophobic adsorption at low ionic strength and on MANAE–agarose supportby ionic adsorption. CNBr–agarose was used as support for the covalent attachmentimmobilization. Immobilization yields of 71, 90 and 97% were obtained when Y lipolyticalipase was immobilized into octyl–agarose, octadecyl–sepabeads and MANAE–agarose,respectively. However, the activity retention was lower (34% for octyl–agarose, 50% foroctadecyl–sepabeads and 61% for MANAE–agarose), indicating that the immobilized lipaselost activity during immobilization procedures. Furthermore, immobilization by covalentattachment led to complete enzyme inactivation. Thermal deactivation was studied at atemperature range from 25 to 45°C and pH varying from 5.0 to 9.0 and revealed that thehydrophobic adsorption on octadecyl–sepabeads produced an appreciable stabilization of thebiocatalyst. The octadecyl–sepabeads biocatalyst was almost tenfold more stable than freelipase, and its thermal deactivation profile was also modified. On the other hand, the Y lipolytica lipase immobilized on octyl—agarose and MANAE—agarose supports presentedlow stability, even less than the free enzyme.