Advancing arabinose-based bioproduction in Yarrowia lipolytica by integrating metabolic engineering and adaptive laboratory evolution

The oleaginous yeast, Yarrowia lipolytica has gained interest as a biotechnological chassis to produce foods, chemicals, pharmaceuticals, and biofuels. To reduce production costs and sustainability, inexpensive and abundant feedstocks such as lignocellulose must be used for bioproduction. Since lignocellulosic biomass contains components that cannot be utilised by Y. lipolytica, it is important to use engineering biology to enable their utilisation. L-arabinose is the second most abundant pentose in lignocellulose after xylose. However, it has received much less attention than xylose as a bioresource. In the present study, we first engineered Y. lipolytica to grow on L-arabinose as the sole carbon source. We used several wild-type and engineered strains to express the multigene arabinose cassette. Second, we used adaptive laboratory evolution to improve the utilisation of arabinose by the engineered strains. Third, we enabled the production of β-carotene from arabinose by expressing a β-carotene cassette in the evolved strain. Using minimal YNB medium supplemented with 20 g/l of arabinose as the sole carbon source resulted in the complete utilisation of L-arabinose within 120 h. In bioreactors, a β-carotene production of 418.89 mg/l was achieved with the complete utilisation of 60 g/l of L-arabinose. This study is the first to engineer L-arabinose utilisation in Y. lipolytica, opening new avenues for biomanufacturing using alternative carbon sources.