Changes in the Activity of Lipases in the Presence of Synthetic and Natural Polymers

Abstract

Abstract—Both synthetic and natural polymers are promising carriers for the immobilization of enzymes, including lipases from different sources. This research trend is of fundamental and applied importance, since immobilized lipases are widely used in various biotechnological processes. In the present work, we study how synthetic and natural polymers (polystyrene, polylysine, and chitosan) influence the catalytic properties of lipases from the hog’s pancreatic gland (LPP), yeast fungus Сandida cylindracea (LCC), and wheat germs (LWG) in the hydrolysis of triacetin (used as a substrate in all the experiments). A polystyrene-based latex (even without surface modification) is found to have a strong effect on the activity of lipases of different origins. In the presence of large particles with a size of about 1 μm (irrespective of their concentration in the range of 1–10%), the activity of all three lipases (LPP, LCC, and LWG) significantly increases compared to the nonimmobilized enzyme. A polystyrene latex with a carboxylated surface shows another effect on the catalytic properties of these lipases. The activity of LPP is found to depend on the concentration of chitosan (at ratios ranging from 100 : 1 to 1 : 1), as well as on the parameters of the medium (pH and temperature). The measurement of the catalytic activity of lipase with polylysine showed that, at ratios of 10 : 1 and 5 : 1 (LPP was in excess), the activity of enzyme increased by 17 and 9% relative to the free form, respectively. This is due to the interaction between the positively charged polylysine and the enzyme having an extra negative charge. The results obtained seem promising for biotechnological applications.