Investigation of the Potential Mechanisms of Limonene Resistance in Meyerozyma Caribbica by Comparative Genomics

Terpene bioconversion presents a sustainable alternative to chemical synthesis for producing high-value compounds, yet its application is constrained by the inherent toxicity of terpenes to microbial biocatalysts. Bioprospecting offers a cost-effective strategy to overcome this limitation and through this approach a strain of Meyerozyma caribbica , with a profile of resistance to the monoterpene limonene, was isolated from Solanum lycocarpum . This study aimed to elucidate the molecular mechanisms underlying this resistance through comparative genomics. These in silico analyses against five food-industry relevant yeasts ( Saccharomyces cerevisiae, Kluyveromyces marxianus, Spathaspora passalidarum, S. arborariae , and Scheffersomyces stipitis ) identified 58 orthologs gene clusters and highlighted 26 proteins belonging to the Major Facilitator Superfamily (MFS) transporter in M. caribbica . Homology modeling and molecular docking analyses demonstrated a satisfactory binding affinity between limonene and the generated MFS protein models, supporting their potential role as specific efflux pumps. Quantitative PCR analysis identified a specific clade within the MFS transporter superfamily that was significantly upregulated under limonene stress. However, experimental validation revealed that intracellular limonene concentrations in M. caribbica following exposure to 4% (v/v) limonene were not significantly lower than those measured in susceptible yeast strains. The confluence of in silico and experimental evidence strongly indicates that the limonene resistance in M. caribbica is mediated by the active efflux of the compound, facilitated by specific MFS transporters. These findings establish M. caribbica as a promising biological chassis for the industrial bioconversion of limonene into value-added products.