About the role of typical spacer/crosslinker on the design of efficient magnetic biocatalysts based on nanosized magnetite

PAULA NICOLÁS; VERÓNICA LASSALLE; MARÍA LUJÁN FERREIRA

JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 122 p. 296 - 304

1381-1177

tThe immobilization of Candida antarctica lipase B (CALB) was carried out using glutaraldehyde (GLUT)and/or 3-aminopropyl-triethoxisilane (APTS). The aim of this work was to elucidate the role of thesecrosslinkers/functionalizers on the efficiency of the prepared nanosized catalysts in solvent-free oleicacid esterification.A series of biocatalysts were prepared in presence or absence of GLUT and APTS. The impact of theamount of initial CALB was also explored. An experimental design was utilized to study the variables thatmaximize biocatalyst activity.A strong dependence of enzymatic activity with the nominal amount of GLUT as well as the finalprotein/CALB loading was found. Nominal quantity of APTS did not affect catalyst?s activity when usedin combination with GLUT. Additional studies demonstrated that stability during storage was mainlydependent on the enzyme loading. The optimum biocatalyst was reused six cycles without mass loss.Biocatalyst?s performance decreased with reuse. Mechanisms justifying these results were proposed.The role of GLUT and APTS on stability during storage and on differences between initial enzymaticactivity and the performance in the reaction after two months was discussed. The problem of mixedinteraction of CALB (covalent bonding plus simple adsorption) was carefully addressed to explain leachingof the lipase.Leaching and stability on storage should be included in the analysis of modifiers impact when support?smodifiers are used. The fresh and stored biocatalyst enzymatic activity has to be addressed looking at thepractical aspects of implementation in technological settings.