title: Production of a novel mannosylerythritol lipid containing a hydroxy fatty acid from castor oil by Pseudozyma tsukubaensis.
abstract: Mannosylerythritol lipids (MELs) are glycolipid biosurfactants produced by various yeasts belonging to the genus Pseudozyma, which exhibit excellent surface activities as well as versatile biochemical activities. A study on P. tsukubaensis NBRC1940 as a mono-acetylated MEL (MEL-B) producer revealed that the yeast accumulated a novel glycolipid from castor oil at a yield of 22 g/L. Its main chemical structure was identified as 1-O-β-(2'-O-alka(e)noyl-3'-O-hydroxyalka(e)noyl-6'-O-acetyl-D-mannopyranosyl)-D-erythritol designated as "new MEL-B." The new MEL-B, comprising a hydroxy fatty acid had a reduced surface tension of 28.5 mN/m at a critical micelle concentration (CMC) of 2.2×10⁻⁵ M in water. The observed CMC was 5-fold higher than that of conventional MEL-B. When conventional MEL-B was dispersed in water, it self-assembled to form the lamellar (L(α)) phase at a wide range of concentrations. In contrast, new MEL-B formed spherical oily droplets similar to the sponge (L₃) phase, which is observed in aqueous solutions of di-acetylated MEL (MEL-A). The data suggest that the newly identified MEL-B is likely to have a different structure and interfacial properties compared to the conventional MELs, and could facilitate an increase in the application of glycolipid biosurfactants.
authors.affiliation: Toyobo Co., Ltd. Tsuruga Institute of Biotechnology, Tsuruga-Fukui, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Tokuma
authors.initials: T
authors.lastname: Fukuoka
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Imura
authors.forename: Tomotake
authors.initials: T
authors.lastname: Morita
authors.forename: Shusaku
authors.initials: S
authors.lastname: Yanagidani
authors.forename: Dai
authors.initials: D
authors.lastname: Kitamoto
authors.forename: Masaru
authors.initials: M
authors.lastname: Kitagawa
mesh_terms: D001487:Basidiomycota / Q000378:metabolism*; D002368:Castor Oil / Q000378:metabolism*; D005227:Fatty Acids / Q000737:chemistry*; D006017:Glycolipids / Q000096:biosynthesis* / Q000737:chemistry*; D008823:Micelles; D013500:Surface Tension; D013501:Surface-Active Agents; D014867:Water
chemical_list: D005227:Fatty Acids; D006017:Glycolipids; D008823:Micelles; D013501:Surface-Active Agents; C439671:mannosylerythritol lipid; D014867:Water; D002368:Castor Oil