Determination of B-glucosidase activity in soils with a bioanalytical sensor modified with multiwalled carbon nanotubes

PATRICIA W. STEGE; GERMÁN A. MESSINA; GUILLERMO BIANCHI; ROBERTO A. OLSINA; JULIO RABA

ANALYTICAL AND BIOANALYTICAL CHEMISTRY

SPRINGER HEIDELBERG

Año: 2010 vol. 397 p. 1347 - 1353

1618-2642

Abstract Soil microorganisms and enzymes are the primary mediators of soil biological processes, including organic matter degradation, mineralization, and nutrient recycling.They play an important role in maintaining soil ecosystem quality and functional diversity. Moreover, enzyme activities can provide an indication of quantitative changes in soilorganic matter. β-Glucosidase (β-Glu) activity has been found to be sensitive to soil management and has been proposed as a soil quality indicator because it provides an early indication of changes in organic matter status and its turnover. The aims of the present study were to test and use a simple and convenient procedure for the assay of β-Glu activity in agricultural soil. The method described here is based on the enzymatic degradation of cellobiose by β-Glupresent in the soil sample and the subsequent determination of glucose produced by the enzymatic reaction using screen-printed carbon electrodes modified with multiwalledcarbon nanotubes (SPCE-CNT) equipped with coimmobilized glucose oxidase and horseradish peroxidase enzymes. The potential applied to the SPCE-CNT detection was −0.15 V versus a Ag/AgCl pseudo-reference electrode. A linear calibration curve was obtained in the range 2.7–11.3 mM with a correlation coefficient. In the present study, an easy and effective SPCE-CNT-modified electrode allowed an improved amperometric response to be achieved and this is attributed to the increased surface area upon electrode modification.