Formation and analysis of mannosylerythritol lipids secreted by Pseudozyma aphidis

Abstract

Pseudozyma aphidis DSM 70725 was found to be a novel producer of mannosylerythritol lipids (MELs). The MELs were quantified by HPLC. Glucose as carbon source for precultivation supported growth well. By contrast, at concentrations >30 g l(-1) in preculture, subsequent MEL formation in the main culture with soybean oil as sole carbon source was reduced. The type of substrate supply considerably influenced MEL formation. High concentrations of soybean oil (80 ml l(-1)) at init favored the production process when compared to a stepwise (20 ml l(-1)) addition. Mannose or erythritol were suitable second carbon sources that enhanced the MEL yield with soybean oil as preferred primary substrate. After 10 days, a maximum yield of 75 g l(-1) was attained during shake-flask cultivation. Biofuel (rapeseed oil methyl ester) also resulted in high yields of MEL, but glucose reduced the MEL yield. Analysis by GC-MS showed that all fatty acids contained in MEL and derived from soybean oil or related methyl ester were degraded by C2-units to differing extents. The surface (water/air) and interfacial (water/hexadecane) tension of the MELs produced from different carbon sources were reduced to a minimum of 26.2 mN m(-1) and 1 mN m(-1), respectively.

Recent developments in microbial oils production: a possible alternative to vegetable oils for biodiesel without competition with human food?

“…Gas chromatography was the first method used for identification of lipids (Wynn and Ratledge 1997) but some prefer GCMS (Rattray et al 1975). Other methods such as HPLC (Rau et al 2005), Infra-red spectrophotometry (Peng and Chen 2008b) or NMR (Horst et al 2009) have also been used for the identification of lipids. …”

Characterization of New Types of Mannosylerythritol Lipids as Biosurfactants Produced from Soybean Oil by a Basidiomycetous Yeast, Pseudozyma shanxiensis

“…rugulosa 5) and P. aphidis 6) , MEL-A is mostly produced and comprises more than 70% of the total MELs ( ). However, MEL-A has a drawback in handling of the aqueous solution due to its very low water-solubility, namely "hydrophilicity" 2) : this has partially limited practical application of MELs.…”

Biosurfactant-producing yeasts widely inhabit various vegetables and fruits

“…1 and 4). Pseudozyma aphidis 28) and Pseudozyma rugulosa 29) are known as high-level MEL producers. They provide a mixture of MEL-A, MEL-B, and MEL-C efficiently.…”