Bioconversion of Glucose and Glycerol into Glycolipid Mannosylerythritol lipid (MELs) by the Yeast Pseudozyma hubeiensis Y10BS025

Abstract

The Pseudozyma Y10BS025 is a yeast isolate collected at Biotecnology Culture Collection (BTCC) LIPI. The strain was isolated from sirih leaf, a local tree of Indonesia, and was shown to produce a glycolipid, mannosylerythritol lipid (MELs-Y10BS025) from vegetable oil. Molecular taxonomic analysis using the D1/D2 domains of the large sub unit 26S rRNA gene, the name P. hubeiensis was proposed for the novel species, with Y10BS025 as the type strain. When grown on appropriate condition, it showed capability to accumulate a large amount of glycolipids, MELs. Based on thin layer chromatography (TLC) analysis, the extracellular glycolipids showed nearly the same spots as those of the MELs produced by P. antarctica, a well known MEL producer. The quantitative analysis on high performance liquid chromatography (HPLC) obtained that the strain has a much higher glycolipid production yield. The glycolipid purification by column chromatography and extraction using different solvents resulted that the spot identified MELs-A produced by P. hubeiensis on TLC. The structure of the major glycolipid was analyzed by 1H nuclear magnetic resonance (NMR) methods, and was shown to be the same as MEL produced by P. antarctica. The optimum of production condition was determined by varying important factors for growth, such as initial carbon sources and inducer of vegetable oil. These results demonstrated that the local strain of the genus Pseudozyma under the optimal condition in a two stage culture, glucose-glycerol (75:25) and soybean oil, provided high efficiency in MELs production of glycolipid. The strain P. hubeiensis Y10BS025 gave the best yield of MELs (115 g/L) after 8 days.