Understanding Thermotolerance of Kluyveromyces Marxianus: A Constraint-Based Modelling Approach

Kluyveromyces marxianus is one of thermotolerant yeast, which can metabolise a broad range of carbon sources, including less conventional lactose, xylose, arabinose and inulin. Such phenotypic trait is sustained even up to 45 °C, what makes it relevant candidate for industrial biotechnology applications, such as ethanol production. It is thus imperative to unravel the key factors, contributing to such phenotype of K. marxianus. The recent yeast studies suggested, that thermotolerance is achieved by reducing the number of growth-determining proteins or suppressing oxidative phosphorylation. In our work we aimed to find the related factors, which contribute to thermotolerance of K. marxianus. We utilized publicly available Kluyveromyces lactis genome-scale metabolic model as a template model for K. marxianus model reconstruction. The model was then carefully refined to include the missing species-specific metabolic capabilities. Gene essentiality analysis was performed to evaluate the model quality. Thereafter we coupled the model with thermodynamic constraints and performed simulations in various growth temperatures. Such approach provided a detailed insight in the favourable flux distribution for particular temperature. We also tried to include the findings from other studies and evaluate the model behaviour.