Enzymatic activity measured by microcalorimetry in soil amended with organic residues

Abstract

SUMMARYEnzymatic activity is an important property for soil quality evaluation. Two sequences of experiments were carried out in order to evaluate the enzymatic activity in a soil (Rhodic Eutrudox) amended with cattle manure, earthworm casts, or sewage sludges from the municipalities of Barueri and Franca. The activity of commercial enzymes was measured by microcalorimetry in the same soil samples after sterilization. In the first experiment, the enzyme activities of cellulase, protease, and urease were determined in the soil samples during a three month period. In the second sequence of experiments, the thermal effect of the commercial enzymes cellulase, protease, and urease on sterilized soil samples under the same tretaments was monitored for a period of 46 days. The experimental design was randomized and arranged as factorial scheme in five treatments x seven samplings with five replications. The treatment effects were statistically evaluated by one-way analysis of variance. Tukey´s test was used to compare means at p ≤ ≤ ≤ ≤ ≤ 0.05. The presence of different sources of organic residues increased the enzymatic activity in the sampling period. Cattle manure induced the highest enzymatic activity, followed by municipal sewage sludge, whereas earthworm casts induced the lowest activity, but differed from control treatment. The thermal effect on the enzyme activity of commercial cellulase, protease, and urease showed

Carbon mineralization, biological indicators, and phytotoxicity to assess the impact of urban sewage sludge on two light‐textured soils in a microcosm

“…Because the incubation was carried out in a closed system, slight differences in metal mass balance between W1 and W12 were likely due to variations in analytical conditions. Conversely, positive correlations with bacterial biomass ( r = .82–.99), protease ( r > .84), and CO 2 emission ( r > .89) in both soils prove that the observed dose‐dependent accumulation of the four metals did not induce toxic effects on microbial growth and activities (Cenciani et al., 2011). Total concentration of the four heavy metals remained for instance below the regulatory limits for agricultural soils as stipulated by the European Council Directive no.…”

“…Cenciani et al. (2011) reported that subproducts of N mineralization, such as amino acids, NO 2 − , and NO 3 − , are in turn used as final electron acceptors by new groups of soil microorganisms.…”

“…Protease activity plays a major role in the N cycle in soil through the hydrolysis of proteins, polypeptides, and oligopeptides to amino acids (Naga Raju, Golla, & Vengatampalli, 2017). Consequently, significant dose‐dependent correlations with bacterial growth were evident in Soil A ( r = .94) and Soil S ( r = .99) (Cenciani et al., 2011). As illustrated in Figure 2, comparable enzyme activities for same treatments in both soils regardless of sampling date, indicating that proteolysis is more dependent on microbial production rather than on soil texture (Vranova, Rejsek, & Formanek, 2013).…”

“…They are the proximate agents of organic matter formation and decomposition (Zhao et al., 2016). For instance, the activity of protease, cellulase, and phosphatase in soil has critical relationships with N, C, and P recycling, respectively (Cenciani, Freitas, Critter, & Airoldi, 2011; Nannipieri, Giagnoni, Landi, & Renella, 2011). Therefore, changes in soil conditions may have significant effects on enzyme activity and nutrient cycling, which rely on microorganisms (Sofi et al., 2016; Zoghlami et al., 2016a).…”

◾ An Account in Calorimetric Research: From Fundamentals to Pharmaceuticals

“…This, in turn, allowed the calculation of both catalytic rate constants and activation parameters for the reaction, and it was emphasized that the universality of the method made it generally promising for studies of macromolecular substrates. The two former examples were both concerned with enzymes from the glycoside hydrolase family, but some calorimetric studies of heterogeneous catalysis using other enzymes including lipases and proteases have also been published (Sotoft et al 2010;Cenciani et al 2011). In the following, we will discuss this application of calorimetry with special focus on cellulolytic enzymes.…”