Enkapsulasi Horseradish Peroxidase-Glucose Oxidase (HRP-GOx) dalam Silika Akuagel yang Disintesis dari Abu Sekam Padi untuk Reaksi Enzimatik Glukosa
ABSTRACT: In recent years, the
sol-gel technique has attracted increasing interest as a unique approach to
immobilize biomolecules for bioanalytical applications as well as biochemical
and biophysical studies. In this research, encapsulation of Horseradish
peroxidase-Glucose oxidase (HRP-GOx) enzymes in silica aquagel from rice hull
ash by sol-gel process has been carried out. In addition, the effect of several
parameters (weight ratio of HRP to GOx, pH, temperature, sodium ion
concentration) on enzyme activity was studied, as well. Rice hull ash, which
was produced by ashing at 700 °C, was extracted it's silika by NaOH solution 1
M at 100 °C for two hours to produce sodium silikate (Na2SiO3) solution. The
Na2SiO3 solution with pH of 13 was added with a strong cation exchanger resin,
to produce sol solution with the pH of 4. Encapsulation was emphasized by
mixing sol solution and phosphate buffer pH 7 containing HRP-GOx solution at
volume ratio of buffer to sol solution 1:5. The mixture was transferred into
96-microwell plate and was aged for 24 hours. Enzymatic reaction was carried
out by adding chromogenic solution of phenol and 4-aminoantipyrine (4-AAP) and
b-D-glucose solution (as substrate) into the microwell. Enzymatic activity was
examined by measuring absorbance of product solution at 490 nm with ELISA
reader. Result of enzymatic activity for encapsulated enzymes (SGE) was
compared to that for free enzymes (EB). Results showed that at the investigated
condition, HRP-GOx enzymes gave high activity at weight ratio of HRP to GOx
10:1 and pH 7 for both SGE and EB. Encapsulation caused the enzymes activity
decrease to 53.0±0.2 %. However, SGE was observed to be more stable on pH and
temperature changes than EB. Study on the effect of sodium concentration showed
that the increase of sodium concentration from 0.10 to 0.37 M decreased the
enzymatic activity to 56±0.2%. Reusability test showed that the synthesized SGE
was reusable with activity decrease of 60% within 23 days.
Penulis: Nuryono, Narsito,
Endang Astuti
Kode Jurnal: jpkimiadd080112
