Psychrophiles to Control Ice-Water Phase Changes in Frost-Susceptible Soils

The phase changes of soil water or porous media have a crucial influence on the performance of natural and man-made infrastructures in cold regions. Several treatment methods to mitigate the effects of frost action have been studied earlier, but traditional methods often rely on chemicals, physical techniques, and the reuse of waste materials, which often have limitations. However, certain organisms produce ice-binding proteins (IBPs) or antifreeze proteins (AFPs) to adapt to low temperatures, which can inhibit ice crystal growth by lowering the freezing point and preventing ice crystallization without the need for external intervention. This study explores the potential of three psychrophilic microbes: Sporosarcina psychrophile , Sporosarcina globispora , and Polaromonas hydrogenivorans , to induce non-equilibrium freezing point depression and thermal hysteresis in order to control ice lens growth in frost-susceptible soils. The growth profiles of the microbes, the concentration of released proteins in the extracellular solution, and the thermal properties of the protein-mixed soils are monitored at an interval of three days. The controlled soil showed a freezing point of -4.59 0 C and thermal hysteresis of 4.62 0 C, whereas protein-treated soil showed a maximum freezing point depression of -8.54 0 C and thermal hysteresis of 7.71 0 C. Interestingly, except for the controlled sample, all the protein-treated soil samples were thawed at a negative temperature (minimum recorded at -0.85 0 C). Further analysis showed that the treated soils compared to porous media mixed soil freeze (1.25 0 C vs. 0.51 0 C) and thaw (2.75 0 C vs. 1.72 0 C) at extensive temperature gap. Overall, this study presents a novel bio-mediated approach using psychrophilic microbes to control ice formation in frost-susceptible soils.