Abstract: This study aimed to screen protease-producing microbial strains capable of effectively reducing polyphenol oxidase (PPO) activity to address enzymatic browning in potato processing. Strains isolated from soil, decaying fruits and vegetables, and fermented soybean products were subjected to preliminary screening through protein hydrolysis circle-to-colony diameter ratio, protease activity determination, and anti-browning experiments. The target strain was identified via 16S rDNA sequencing, and its fermentation products were added to potato powder at a 3:1 (V/M) ratio. After treatment at 0, 0.5, 2, 4, 8, and 12 h intervals, key indicators including browning degree and PPO activity were measured. Additionally, the experimental conditions were further optimized, focusing on the sonication time for cell lysate preparation and the treatment concentration of crude protein. Results demonstrated that strain G3 exhibited notable browning inhibition, with its inhibitory effect potentially closely associated with protease activity. Consequently, G3 was selected as the target strain and identification revealed 99% homology with Serratia marcescens. When the fermentation sediment resuspension of G3 was used to treat potato slurry for 12 h, its protease activity increased to approximately 3.2-fold of the control, PPO activity decreased by 69.75% and browning degree was significantly reduced (P<0.05). The G3 cell lysate obtained under optimal sonication conditions (200 W, 45 min) also demonstrated excellent browning inhibition effects. Furthermore, the purified G3 crude protein, when applied to potato slurry at a concentration of 5.0 g/L for 8 h, effectively reduced PPO activity by 78.6%, significantly suppressing enzymatic browning (P<0.05). In conclusion, the proposed technological approach of screening protease-producing microbial strains to inhibit PPO activity through their fermentation products proves feasible for addressing enzymatic browning.