Full-depth reclamation (FDR) is a method for restoring damaged pavements by pulverizing the asphalt layer along with the base and subbase materials, mixing them with stabilizing agents, and compacting them to form a new base layer. This study explores biochemical stabilization using cement and the bio-enzyme Terrazyme, alongside stabilization with fly ash. Bio-enzyme terrazyme, derived from vegetable extract fermentation, is an affordable and sustainable stabilizer compared to traditional options. Fly ash, a coal by-product serves as an alternative to cement in the stabilization process. The study aims to find out the optimal design mix by stabilizing the 2 compositions of reclaimed asphalt pavement (RAP) the asphalt layer to the granular base material in the ratio 40/60 and 30/70 with varying dosages of cement terrazyme to get minimum Unconfined Compression Strength (UCS) of 4.5 MPa after 28 days of curing according to Indian Road Congress (IRC) guidelines for the base layer. Additionally, the research investigates the impact of 20% fly ash on UCS. The results are intended to enhance the understanding of FDR effectiveness and contribute to more sustainable pavement rehabilitation practices.