Abstracts Book - IMRC 2018

• SB2-O025
SYNTHESIS OF NANOCRYSTALLINE CALCIUM PHOSPHATE FOR
IMMOBILIZATION OF CELLULASES
Manuel Alejandro Valdes 1 , Dulce María Guzmán 2 , Cristian Salas Torres 2 , Sofía Nava Coronel 2 ,
Guillermo Capistrano Zuñiga Neria 1 , Juan Javier Guillen 1 , Israel Pala Rosas 3
1
Instituto Tecnológico Superior de Ciudad Hidalgo, Departamento de nanotecnología y
mecatrónica, Mexico. 2 Instituto Tecnológico Superior de Ciudad Hidalgo, Departamento de
nanotecnología, Mexico. 3 Instituto Politécnico Nacional - IPN - ESIQIE, Secretaría de Estudios de
Posgrado e Investigación, Mexico.
Enzymatic immobilization improves protein stability and catalytic activity so
there is great interest in obtaining suitable supports. Due to their dimensions,
nanomaterials present large interaction areas with enzymes, and therefore, the
protein stabilization of the final solid is enhanced. In this work, calcium
phosphate was synthesized at 3 different pH by the chemical precipitation
method and was characterized by X-ray diffraction (XRD), Fourier-transform
infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The
results showed that hydroxyapatite crystals with hexagonal structure and OH
functional groups were obtained. Cellulases of Aspergillus sp. were immobilized
by physical adsorption and by covalent binding, besides a comparison between
the synthesized nanocrystals, calcium phosphate nanofibers and comercial
samples. In all the samples, a decrease of the catalytic activities of
endoglucanase, exoglucanase, beta-glucosidase and FP-ase was observed to
less than half of the initial one, indicating the of the enzymes to the different
supports. The complex formed by the nanocrystals synthesized at pH=6.4 was
the sample that showed the smallest decrease in activities either by physical
adsorption of by covalent binding. In addition, the reaction of sugars reduction
was carried out with different concentrations of glucose in presence of the
different samples of immobilized enzymes, which it seems that the nanocrystals
do not inhibit the reaction.
Keywords: Hydroxyapatite, nanocrystals, enzyme immobilization
Presenting authors email: guzmndulce@gmail.com