Effects of white colony-forming yeast on microbial communities and metabolites in kimchi

White colony-forming yeast (WCFY) forms white colonies on kimchi during fermentation, causing off-flavors and quality deterioration, which are significantly damaging to kimchi industry. To study its impact, kimchi samples were inoculated with representative WCFYs (Candida sake, Debaryomyces hansenii, Kazachstania servazzii, and Pichia kudriavzevii) and monitored for 50 days at 15 °C using high-throughput DNA sequencing and gas chromatography/mass spectrometry. Dominant bacteria at the end of fermentation were Companilactobacillus and Latilactobacillus in the control and WCFY-inoculated samples, respectively. The fungal communities of control sample remained stable, whereas those for WCFY-inoculated samples showed Kazachstania or Pichia dominance. Metabolite analysis revealed significant increases in glycerol, erythritol, and myo-inositol in WCFY-inoculated samples. Correlation analysis showed that Lactococcus and Weissella were negatively correlated with Kazachstania. This study underscores ecological role of WCFYs in kimchi fermentation, particularly their impact on microbial communities and metabolites, suggesting the need for strategies that control WCFY growth to improve kimchi quality.