Selective and oriented immobilization of (phospho) lipases from the Caribbean Sea anemone Stichodactyla helianthus (Ellis, 1768) by interfacial adsorption

Abstract

Immobilized lipases by interfacial adsorption on hydrophobic supports are enzymatic systems which show
confirmed potentialities for diverse applications such as bioconversion. On the other hand, enzymes from marine invertebrates
show unusual substrate specificities, which make them promising targets for the development of immobilized
biocatalysts. In this work, the authors describe the immobilization, by interfacial adsorption on Octyl-Sepharose CL 4B
support, of two (phospho)lipases: Sticholysins I and II, and a high molecular weight esterase activity from the whole
extract of the Caribbean Sea anemone Stichodactyla helianthus. Immobilization was selective for lipases, which showed
esterolytic activity towards p-nitrophenylacetate, β-naphtylcaprilate and tributyrin. This esterolytic activity of the Sticholysins
towards non-phospholipid substrates had not been previously reported. The apparent maximal specific enzymatic
activity towards p-nitrophenylacetate was lower in the immobilized derivatives than in soluble samples. Immobilization
was also oriented, since it increased the apparent affinity by substrate, which indicates a higher accessibility to the active
sites. 68 % of immobilized (phospho)lipases preserved tributyrin-hydrolyzing activity. These enzymes require Ca2+ ion
to hydrolyze p-nitrophenylacetate and were inhibited by p-nitrophenylacetate concentrations higher than 1.185 mmol/L.
Ca2+ concentrations of 40 mmol/L overcame the substrate-excess inhibition from immobilized extract. These kinetic
characteristics suggest the potential use of the obtained biocatalysts on enzymatic bioconversion.