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.
Department of Biochemical and Microbial Technology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium. inge.vanbogaert@ugent.be
Inge N A
IN
Van Bogaert
Julia
J
Sabirova
Dirk
D
Develter
Wim
W
Soetaert
Erick J
EJ
Vandamme
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