Identification of superior lipid producing Lipomyces and Myxozyma yeasts

Abstract

Oleaginous yeasts are of interest for production of single cell oils from sugars. Eighteen members of the <em>Lipomyces</em> and <em>Myxozyma</em> clade were screened for lipid production when cultured on 10%w/v glucose. The highest ranking yeasts included <em>L. tetrasporus</em> (21 g/L), <em>L. spencer-martinsiae</em> (19.6 g/L), and <em>L. lipofer</em> (16.7 g/L). By contrast, <em>Rhodosporidium toruloides</em>, which was included as a positive control, produced 16.7 g/L. The <em>L. tetrasporus</em> and <em>L. lipofer</em> were further characterized for growth and lipid production on sugars present in biomass hydrolysates. These included L-arabinose, xylose, and an equal glucose and xylose mixture. <em>L. tetrasporus</em> had lipid titers of 16.3–20.8 g/L and <em>L. lipofer</em> 12.5–17.0 g/L. When both strains were grown on an equal mixture of glucose and xylose, xylose was consumed immediately following glucose. Lipid contents for the yeasts consisted primarily of C18:1 and C16:0, which makes them a promising source of lipids for fuel applications.