Evaluation of the influence of chemical and physical factors on mixtures of fungal and plant lipases

Abstract

Lipases are biocatalysts that may have distinct biochemical characteristics depending on the source. The combination of lipases from different sources with complementary characteristics is a viable strategy for increasing the enzymatic activity. In this study, fungal (Aspergillus niger 01 - CBMAI 2084) and plant (orange frit - orange peel fragment) lipases were analyzed separately and together in different concentrations. In addition, we evaluated the influence of organic solvents and ultrasonic effect on lipase activity, as well as substrate specificity [p-nitrophenyl butyrate (pNPB), p-nitrophenyl- laurate (pNPL) and p-nitrophenyl-palmitate (p-NPP)] and enzymatic immobilization in different supports (celite, silica, aluminum oxide, Lewatti, calcium alginate and gelatin). Increased enzyme activity was observed in formulations with higher concentration of fungal extract. The combination of 50% fungal extract and 25% plant extract increased about 55% lipase activity, showed the highest absolute lipase activity among all combinations and was selected for the following study. Plant extract showed the highest lipase activity in the hydrolysis of p-NPB and p-NPL, however, fungal extract showed the highest hydrolytic activity on p-NPP. When applied to synthetic substrates, the combination of plant and fungal extracts showed less stability and activity in synthetic substrates than isolated extracts, however lipase activity increased after 20s on ultrasound bath. Regarding to immobilization techniques, the adsorption on silica was the most efficient for all lipase extracts.