Enhanced separation and analysis procedure reveals production of tri-acylated mannosylerythritol lipids by Pseudozyma aphidis

Abstract

Mannosylerythritol lipids (MELs) are one of the most promising biosurfactants because of their high fermentation yields (>100 g l) and during the last two decades they have gained a lot of attention due to their interesting self-assembling properties and biological activities. In this study, MELs were produced by fed-batch bioreactor fermentation of rapeseed oil with Pseudozyma aphidis MUCL 27852. This high-level MEL-producing yeast secretes four conventional MEL structures, -A, -B, -C and -D, which differ in their degree of acetylation. During our research, unknown compounds synthesized by P. aphidis were detected by thin-layer chromatography. The unknown compounds were separated by flash chromatography and identified as tri-acylated MELs by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The third fatty acid chain on the tri-acylated MELs was positioned on the primary alcohol of the erythritol moiety and comprised long-chain acids, mainly oleic and linoleic acid, which are not found in conventional di-acylated MELs. Furthermore, the LC-MS analysis time of conventional MELs was reduced to almost one-third by switching from HPLC-MS/MS to ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Provided optimization of the fermentation yield, P. aphidis could be an interesting novel producer of tri-acylated MELs and, thereby expand the supply and applicability of biosurfactants.

Efficient production of tri-acetylated mono-acylated mannosylerythritol lipids bySporisoriumsp. aff.sorghiSAM20

“…The results of LC-ESI-MS analysis of the purified GL-A are summarized in Table 3. The GL-A molecules were detected as adducts with ammonia, [M + NH 4 ] + , according to those reported by Onghena et al (2011) and Goossens et al (2016). The mass range of 592-676 Da and possible fatty acid compositions including C10-C18 were predicted for the GL-A molecules.…”

“…() and Goossens et al . (). The mass range of 592–676 Da and possible fatty acid compositions including C10–C18 were predicted for the GL‐A molecules.…”

“…; Goossens et al . ). Surfactants with HLB of 7–9 and 8–18 are considered as wetting agents and oil‐in‐water emulsifiers, respectively (Tadros ).…”

“…The HLB value of GL-A was estimated to be 8Á7 by the Griffin's method. The HLB values of about 6, 8 and 12 have been reported for tri-acylated, di-acylated and mono-acylated MELs, respectively Goossens et al 2016). Surfactants with HLB of 7-9 and 8-18 are considered as wetting agents and oil-in-water emulsifiers, respectively (Tadros 2005).…”

Experimental Evidence on the Nature of the Antigen in the Direct Agglutination Test for Visceral Leishmaniasis

“…Thin layer chromatography (TLC). Thin layer chromatography to separate the different fractions from the LPG extraction described previously was performed as described by Goossens et al 23 In brief, the fractions extracted with solvent B, C, and D were dried by vacuum centrifugation, and the dry weight was measured and solubilized to 10 mg/mL in chloroform/methanol (1:4). Twenty microliters of the sample was spotted on silica gel 60 TLC plates (Merck, Darmstadt, Germany) and separated in a TLC chamber using isopropanol/pyridine/ water (1:1:1) as the solvent system.…”