Metabolic and genomic insights into erythritol production and foam stability in Yarrowia lipolytica

Erythritol is a low-calorie sweetener produced by Yarrowia lipolytica in industrial fermentation processes. However, excessive foam formation can hinder fermentation efficiency. This study compares two Y. lipolytica strains, F4 and 167, which exhibit distinct abilities to produce erythritol and generate foam. After 96 hours of fermentation, F4 produced 2.28 times more erythritol than 167 and generated foam with greater persistence. Foam stability testing revealed that foam produced by F4 exhibited a higher initial height and a longer half-life, indicating superior foam stability. Metabolomic profiling showed higher levels of phosphatidylcholine and phosphatidylethanolamine in F4, which were consistent with lower interfacial tension and stronger foam stability. Additionally, F4 showed enrichment of amino-acid-related metabolic features, particularly those involving alanine, aspartate, and glutamate. Genomic analysis identified strain-specific differences in genes related to cell wall biogenesis and lipid biosynthesis. These findings indicate that the stronger foam stability observed in F4 is more consistent with lipid-associated interfacial activity, whereas the higher erythritol accumulation is consistent with stronger reducing power through the pentose phosphate pathway. Total protein concentration and apparent viscosity showed opposite trends relative to foam stability, suggesting that foam persistence was more closely associated with interfacial properties than with bulk viscosity or protein content under the tested conditions. These insights can provide a theoretical basis for optimizing industrial erythritol fermentation processes.