@article{01J5DDHB20W5F83EV86EW2BC42,
  abstract     = {{Background The yeast Starmerella bombicola is renowned for its highly efficient sophorolipid production, reaching titers and productivities of (over) 200 g/L and 2 g/(L h), respectively. This inherent efficiency has led to the commercialization of sophorolipids. While the sophorolipid biosynthetic pathway has been elucidated a few years ago, in this study, it is revisited and true key intermediates are revealed. Results Recently, Starmerella bombicola strains developed and evaluated in the past were reevaluated unveiling unexpected findings. The AT enzyme encoded in the sophorolipid biosynthetic gene cluster is the only described enzyme known to acetylate sophorolipids, while the SBLE enzyme encoded by the SBLE gene is described to catalyze the conversion of (acetylated) acidic sophorolipids into lactonic sophorolipids. A double knockout of both genes was described to result in the generation of bolaform sophorolipids. However, new experiments performed with respective S. bombicola strains Delta sble, Delta at Delta sble, and triangle at revealed inconsistencies with the current understanding of the SL pathway. It was observed that the triangle sble strain produces mainly bolaform sophorolipids with higher acetylation degrees instead of acidic sophorolipids. Furthermore, the triangle at strain produces predominantly bolaform sophorolipids and lactonic sophorolipids with lower acetylation degrees, while the triangle at triangle sble strain predominantly produces bolaform sophorolipids with lower acetylation degrees. These results indicate that the AT enzyme is not the only enzyme responsible for acetylation of sophorolipids, while the SBLE enzyme performs an intramolecular transesterification reaction on bolaform glycolipids instead of an esterification reaction on acidic sophorolipids. These findings, together with recent in vitro data, led us to revise the sophorolipid biosynthetic pathway. Conclusions Bolaform sophorolipids instead of acidic sophorolipids are the key intermediates in the biosynthetic pathway towards lactonic sophorolipids. Bolaform sophorolipids are found in very small amounts in extracellular S. bombicola wild type broths as they are very efficiently converted into lactonic sophorolipids, while acidic sophorolipids build up as they cannot be converted. Furthermore, acetylation of sophorolipids is not exclusively performed by the AT enzyme encoded in the sophorolipid biosynthetic gene cluster and acetylation of bolaform sophorolipids promotes their transesterification. These findings led to the revision of the industrially relevant sophorolipid biosynthetic pathway.}},
  articleno    = {{113}},
  author       = {{Roelants, Sophie and Bovijn, Stijn and Bytyqi, Elvira and de Fooz, Nicolas and Luyten, Goedele and Castelein, Martijn and Van de Craen, Thibo and Diao, Zhoujian and Maes, Karolien and Delmulle, Tom and De Mol, Maarten and De Maeseneire, Sofie and Devreese, Bart and Soetaert, Wim}},
  issn         = {{2731-3654}},
  journal      = {{BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS}},
  keywords     = {{Starmerella bombicola lactone esterase,Biosurfactants,Glycolipids,Bolaform sophorolipids,Lactonic sophorolipids,BIOSURFACTANTS,GENE,STEP}},
  language     = {{eng}},
  number       = {{1}},
  pages        = {{11}},
  title        = {{Bubbling insights : unveiling the true sophorolipid biosynthetic pathway by Starmerella bombicola}},
  url          = {{http://doi.org/10.1186/s13068-024-02557-7}},
  volume       = {{17}},
  year         = {{2024}},
}

Altmetric

View in Altmetric

Web of Science

Times cited: