Extracellular accumulation of mannosylerythritol lipids by a strain of Candida antarctica.

Abstract

A yeast strain, isolated from the exudate of a tree, accumulated biosurfactants abundantly when grownon soybean oil as the sole carbon source. Thebiosurfactants were found to be a mixture of 4 mannosylerythritol lipids, including two new mannosylerythritol lipids as major components. The major components, which amounted to about 80 % of the total lipids, were determined to be 4-0-(di-0-acetyl-di-O-alkanoyl-/?-D-mannopyranosyl)-erythritol and 4-0-(mono-0-acetyl-di-0-alkanoyl-/?-D-mannopyranosyl)-erythritol. The yeast strain was identified as Candida antarctica (Goto et al.) Kurtzman et al. Wepreviously reported that Candida sp. B-7 produced a mannosylerythritol lipid (MEL), that is, 4-O-(2/,6/-di-O-alkanoyl-^-D-mannopyranosyl)-erythritol (designated as MEL-B7), from /7-alkanes or vegetable oils in high concentrations (about 30g/l).1 2) We again tried to screen microorganisms accumulating biosurfactants and succeeded in obtaining some strains by using a selective medium containing soybean oil as a renewable resource. A yeast strain, T-34, was found to extracellularly accumulate anthrone-positive biosurfactants, which were a mixture of MELs showing different Rfvalues from that of MEL-B7 on thin-layer chromatography. This paper describes the screening for microorganisms accumulating biosurfactants, identification of the isolated yeast and characterization of the biosurfactants accumulated by the yeast. Materials and Methods Microorganisms. Strain T-34 used in this study was isolated from the exudate of a tree on Mt. Tsukuba.

Enzymatic Conversion of Diacetylated Sophoroselipid into Acetylated Glucoselipid: Surface-Active Properties of Novel Bolaform Biosurfactants

“…The extracts were analyzed by thinlayer chromatography TLC on silica plates Silica gel 60F; Wako with a solvent system consisting of chloroform/ methanol/water/acetic acid 65:15:2:2, by vol . The compounds on the plates were located by charring at 110 for 5 min after spraying an anthrone/sulfuric acid reagent as previously reported 16 . The mixture of glycolipids was then chromatographed with a close gradient elution of chloroform-methanol 10:0 to 0:10 .…”

Isolation of YeastKurtzmanomycessp. I-11, Novel Producer of Mannosylerythritol Lipid

“…[1][2][3][4] These biosurfactants have received increasing attention because of their special properties such as the diversity of possible chemical structures, low toxicity, biodegradability, and biological activity. Among the biosurfactants, the glycolipid-type biosurfactants produced by yeasts, such as sophorolipids from Torulopsis bombicola [5][6][7] and mannosylerythritol lipids (MEL) from Candida antarctica, 8) Candida sp. SY-16, 9) Schizonella melanogramma 10) and Ustilago sp.…”

“…All known MELs contain Dmannose and meso-erythritol and our data on the glycosides coincided with those of the previously characterized MELs. 8,9,13) Therefore, strain I-11 was considered to be a MEL producer. Morphologically, the strain I-11 looked diŠerent from the previously identiˆed MEL-producing yeast that belongs to Candida species.…”

“…MEL-I-11 had a carbohydrate backbone (mannosylerythritol) indistinguishable from the previously identiˆed MELs, and had the monoacetyl dialkanoyl mannosylerythritol structure similar to those of MEL-B 13) and MEL-SY16. 9) The hydrophobic moieties of MEL-B and MEL-SY16 are composed mainly of fatty acids with chain lengths of C8, C10, or C12, 8) and C6, C12, or C14, respectively. 9) Thus, the fatty acid components of MEL-I-11 were diŠerent from those of MEL-B and MEL-SY16 in composition.…”

“…I-11. So far, the MEL production has been reported in Candida sp., 8,9) Schizonella melanogramma, 10) and Ustilago maydis. 12) Thus, Kurtzmanomyces sp.…”