Low-Cost Safe Utilization of Cadmium-Contaminated Potatoes: A Coupled Strategy of Peeling and Liquid Fermentation with Pichia stipitis

This study presents a safe and scalable strategy for utilizing Cd-contaminated potatoes in rural settings. A peeling–liquid fermentation method using Pichia stipitis was developed and compared with other fermentation modes to evaluate Cd migration and product quality. Peeling reduced initial Cd content by 15.24%, and microbial treatments further lowered residual Cd by 2.02–3.64 fold. Pichia stipitis exhibited high Cd tolerance and retained 31.68% of Cd via chelation in solid fermentation. During liquid fermentation, Lactobacillus dominated (> 90%) and contributed to Cd bioadsorption. Metabolomic profiling identified 18 amino acids; notably, L-cysteine and L-histidine showed strong correlations with microbial shifts (Mantel test, P < 0.001). Spirits produced from peeled, Pichia stipitis -fermented potatoes contained 69 volatiles, with increased levels of esters. The proposed approach ensures effective Cd mitigation while improving flavor characteristics, offering a practical solution for small-scale farmers dealing with heavy metal-contaminated crops.