Effects of urease on strongly alkaline sodium-based dispersive soils from check dams under acidic conditions

This study explores the adaptation of microbial enzymatic techniques, which were originally developed to eliminate amino impurities in alcoholic beverages, for stabilizing strongly alkaline sodium-based dispersive soils from check dams. Employing acid urease from Lactobacillus reuteri ( L. reuteri ) and a control group using soybean-derived urease, this research aimed to modify soil alkalinity through biomineralization. Ultraviolet (UV) mutagenesis optimized L. reuteri strains for biomass and activity. Solution experiments were conducted to assess the effects of pH, temperature, and storage duration on urease activity and to evaluate the calcium carbonate production and crystal morphology of the two ureases under varying calcium ion concentrations. Dispersivity identification tests and tensile strength evaluations were conducted to analyze the disparities in the modified dispersive soil treated with the two types of ureases. The results showed that soybean urease should be stored under low-temperature conditions and a neutral pH, whereas acid urease from L. reuteri can be stored at room temperature across a range of pH levels. Both urease treatments effectively reduced soil dispersivity and improved tensile strength significantly (up to 94% and 177%, respectively), with acid urease from L. reuteri resulting in superior soil strengthening and ammonia regulation. These findings suggest that treating alkaline dispersive soils with acid urease is an efficient and eco-friendly method.