Abstract Desaturation denotes a methodology used to mitigate sand liquefaction. Signifying a new form of material, biogas is deemed more feasible for the purpose of desaturation. The present study entailed the adoption of a microbial denitrification process for generating nitrogen gas to induce specimens that are partially saturated. These specimens were utilized for the consolidated undrained triaxial tests performed isotropically. Based on a simplified process concerning the evaluation of liquefaction, the study provided the crucial degree of saturation for determining its minimum degree for averting liquefaction under varying intensities of earthquake. According to test findings, the soils’ liquification resistance grows with an increase in the saturation degree. The number of loading cycles used for initializing liquefaction increases to 34 cycles from 18 cycles under undrained asymmetricity as the extent of saturation reduces to 95.9 % from 100 % when the similarity of stress ratio is observed. Furthermore, the ratio of liquification resistance goes up in a linear pattern initially as the degree of saturation decreases. Meanwhile the ratio declines as the relationship becomes increasingly nonlinear. As a result, there is a gradual reduction in liquefaction resistance as the magnitude of earthquake rises, with a decline in the critical saturation degree. Notably, the extent of this decline is predicated on the relative density.