Knocking out the MFE-2 gene of Candida bombicola leads to improved medium-chain sophorolipid production.
The nonpathogenic yeast Candida bombicola synthesizes sophorolipids. These biosurfactants are composed of the disaccharide sophorose linked to a long-chain hydroxy fatty acid and have potential applications in the food, pharmaceutical, cosmetic and cleaning industries. In order to expand the range of application, a shift of the fatty acid moiety towards medium-chain lengths would be recommendable. However, the synthesis of medium-chain sophorolipids by C. bombicola is a challenging objective. First of all, these sophorolipids can only be obtained by fermentations on unconventional carbon sources, which often have a toxic effect on the cells. Furthermore, medium-chain substrates are partially metabolized in the beta-oxidation pathway. In order to redirect unconventional substrates towards sophorolipid synthesis, the beta-oxidation pathway was blocked on the genome level by knocking out the multifunctional enzyme type 2 (MFE-2) gene. The total gene sequence of the C. bombicola MFE-2 (6033 bp) was cloned (GenBank accession number EU371724), and the obtained nucleotide sequence was used to construct a knock-out cassette. Several knock-out mutants with the correct geno- and phenotype were evaluated in a fermentation on 1-dodecanol. All mutants showed a 1.7-2.9 times higher production of sophorolipids, indicating that in those strains the substrate is redirected towards the sophorolipid synthesis.
Van Bogaert
Inge N A
IN
Department of Biochemical and Microbial Technology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium. inge.vanbogaert@ugent.be
Sabirova
Julia
J
Develter
Dirk
D
Soetaert
Wim
W
Vandamme
Erick J
EJ
D000595:Amino Acid Sequence; D001483:Base Sequence; D002175:Candida / Q000235:genetics* / Q000378:metabolism*; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D007851:Dodecanol / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics*; D055786:Gene Knockout Techniques; D006017:Glycolipids / Q000378:metabolism*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013501:Surface-Active Agents / Q000378:metabolism
D004271:DNA, Fungal; D005656:Fungal Proteins; D006017:Glycolipids; D013501:Surface-Active Agents; D007851:Dodecanol