Abstract In karst regions characterized by elevated geogenic background levels of heavy metals, the accumulation of soil cadmium has resulted in excessive cadmium concentrations in potato tubers, thereby posing a challenge to the safe utilization of potatoes by local smallholder farmers. This study utilized the potato cultivar Weiyu No. 7 and established a fermentation–distillation system that integrated peeling (peeled & unpeeled), fermentation mode (solid-state & liquid-state), and yeast inoculum ( Saccharomyces cerevisiae & Pichia stipitis ). The study compared cadmium partitioning between potato distillers’ grains (PDG) and potato liquor across different treatments, while also analyzing amino acid profiles and microbial community dynamics to explore potential pathways for cadmium removal. The cadmium content in unpeeled potato mash was measured at 0.64 mg/kg, which is 10.94% higher than that in peeled mash (0.57 mg/kg), indicating that peeling effectively reduced the initial cadmium load entering the fermentation system. Among all treatments, PDG from PLP contained approximately 0.40 mg/kg cadmium, while among peeled treatments, PSP exhibited the highest cadmium chelation efficiency (31.68%). Notably, no cadmium was detected in the potato liquor from any treatment. High-throughput sequencing and targeted metabolomics revealed that in the fermentation broth inoculated with either P. stipitis or S. cerevisiae , the bacterial community was predominantly composed of Lactobacillus , although its relative abundance was significantly lower in the S. cerevisiae groups. Furthermore, sulfur- and nitrogen-containing amino acids were significantly correlated with PDG cadmium levels and community structure, suggesting that chelation, cellular adsorption, and migration with the filtrate collectively contributed to cadmium removal. Volatile analysis indicated that PLP produced spirits that were richer in esters and lactones, exhibiting more pronounced fruity and creamy aromas. Overall, peeling pretreatment combined with P. stipitis -dominated liquid fermentation and distillation mitigates cadmium risk while improving flavor and offers a practical biorefinery pathway for the safe utilization of cadmium-contaminated potatoes exceeding safety limits in rural settings. Graphical Abstract
Tan et al. (Mon,) studied this question.