Effect of Montmorillonite and Organoclay on Urease and L-Asparaginase Activities in Soil

The amidohydrolase play a significant role in maintaining a sustainable environment and an agriculture sector. This is mainly because it is central to biochemical reactions (e.g. organic decompositions, food cycles, and pollutant decomposition). Therefore, keeping these enzymes active and stable in soil is a crucial task. In doing so, the effect of adding montmorillonite and organoclays on activity and stability of these enzymes in soil was investigated. The organic clay was produced by modifying the Na-montmorillonite clay using the hexadecyl trimethylammonium bromide cationic surfactant. To analyze the structural and morphologic profiles of the synthesized organoclay montmorillonite, Field Emission Scanning Electron Microscope (FESEM) and the clay's cation exchange capacity were used. The effects of this organic clay and incubation period on urease and L-asparaginase activities in soil were investigated. Results from statistical analyses showed that the effects of clay type and incubation period on the activity of both enzymes (urease and L-asparaginase) were significant at the 5% level. The activity level of both enzymes in soil samples treated with organic clay (71.48 and 9.01 μgNH4+Ng-12h-1 in urease and L-asparaginase) was significantly higher than in the control (29.12 and 4.22 μgNH4+Ng-12h-1 in urease and L-asparaginase) and montmorillonite clay sample (39.84 and 5.26 μgNH4+Ng-12h-1 in urease and L-asparaginase) s. The maximum declining slope in the activity of both enzymes was observed after 7 days from incubation. The organoclay prepared from the montmorillonite clay successfully maintained soil enzymes. Therefore, use of this organoclay can positively affect enzyme activity and stability.