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

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 soil organic matter. Beta-glucosidase (beta-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 beta-Glu activity in agricultural soil. The method described here is based on the enzymatic degradation of cellobiose by beta-Glu present in the soil sample and the subsequent determination of glucose produced by the enzymatic reaction using screen-printed carbon electrodes modified with multiwalled carbon 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.

Structural and functional differentiation of bacterial communities in post-coal mining reclamation soils of South Africa: bioindicators of soil ecosystem restoration

“…These enzymes are utilised as soil quality indicators for monitoring the response of soil organisms to disturbances in different soil ecosystems 9,[35][36][37][38] . Furthermore, the significant interaction effect of fixed factors on these enzyme activities suggests that they are sensitive to differences between sites and soil disturbances 9,37,39 . The values obtained for enzyme activities in all reclamation soils are within the range obtained for post-oil mining reclamation soils 40 and post-coal mining reclamations soils 19,41 .…”

Influence of Tillage Practices, Organic Manures and Extrinsic Factors on β-Glucosidase Activity: The Final Step of Cellulose Hydrolysis

“…BGa provides an early indication of changes in the status and turnover of soil organic matter (SOM) [3]. This enzyme assay is also useful because it is strongly and positively correlated with soil fertility variables such as available nitrogen or phosphorus and with other soil quality variables such as soil microbial biomass carbon (MBC) [4,5].…”

Soil enzymes associated with carbon and nitrogen cycling in invaded and native secondary forests of northwestern Argentina

“…The higher C:N ratio of the soil in invaded stands is related to the higher levels of potential soil β-glucosidase activity. This enzyme catalyzes the first steps of the hydrolysis of large C-chains and is critical for the further action of enzymes linked to N and P mineralization (Debosz et al 1999;Stege et al 2010).Moreover, since βglucosidase is involved in cellulose catabolism, more abundant and extended litter production in invaded stands (Ligustrum is a perennial species which has an extended period of litter fall) (Aragón 2000;Easdale 2006) may also explain the higher activity of this enzyme in this type of forest.…”

“…β-glucosidases, proteases, ureases and phosphatases are the most important soil enzymes involved in the carbon (C), nitrogen (N) and phosphorus (P) cycles in the soil (Sardans and Peñuelas 2005;Sardans et al 2008). β-glucosidases break down labile cellulose and related carbohydrates with 1-4 glucosidic bonds, degrading plant cell walls and thus contributing to the firsts phases of plant cell tissues decomposition, which then facilitate the activities of other enzymes such as proteases and phosphatases (Debosz et al 1999;Sardans et al 2008;Stege et al 2010). Proteases are involved in the first phase of N mineralization by hydrolyzing the peptide bonds of amino acids.…”