Poster Presentation 1B-28
Method for Immobilizing Invertase
by Adsorption on Dowex Anionic Exchange Resin
Ester Junko Tomotani and Michele Vitolo*
Department
of Biochemical and Pharmaceutical Technology
Av. Prof. Lineu Prestes, 580, B-16,
05508-900
São Paulo, SP, Brazil
Phone: 55-11-30913862
Fax: 55-11-38156386
E-mail: michenzi@usp.br
Invertase
(EC.3.2.1.26) was immobilized by adsorption on Dowex®
anion exchange resins (types: 1X8:50-400; 1X4: 50-400 and 1X2:100-400). An aqueous invertase
solution was mixed with an aqueous suspension of each type of resin,
maintaining the mixture under agitation of 100 rpm by 4h. The complexes Dowex/Invertase
formed were separated by centrifugation (3000xg; 15 min), selecting the complex
for kinetic and thermodynamic characterization, which had an immobilization
coefficient of 100% and no leakage of the enzyme during the reaction. The stability pH intervals for the soluble and
insoluble invertase were 4.0-4.6 and 4.6-5.5,
respectively. In both cases, the optimal
pH values were found in the range of the stability intervals. The KM and Vmax
for the immobilized invertase were 18.3 mM and 0.0450 U/mL, whereas for
the soluble form they were 17.0 mM and 0.0240 U/mL.