Identification of superior lipid producing Lipomyces and Myxozyma yeasts

Authors: Dien, Bruce; Slininger, Patricia - Pat; Kurtzman, Cletus; Moser, Bryan; O Bryan, Patricia

Submitted to: AIMS Environmental Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/4/2016
Publication Date: 1/4/2016
Publication URL: http://handle.nal.usda.gov/10113/62508
Citation: Dien, B.S., Slininger, P.J., Kurtzman, C.P., Moser, B.R., O'Bryan, P.J. 2016. Identification of superior lipid producing Lipomyces and Myxozyma yeasts. AIMS Environmental Science. 3(1):1-20. doi: 10.3934/environsci.2016.1.1.

Interpretive Summary: Triglyerides or lipids are presently manufactured using a variety of commercial crops. In addition to food uses, triglycerides are used for producing biodiesel, polymers, and chemicals. Production of biodiesel is limited by the availability of competitively priced vegetable oils. An alternate route being explored to produce lipids, is to grow lipid producing microorganisms on sugars, which have been produced from fiberous biomass. Examples of algae, bacteria, and yeasts have all been observed to produce superior yields of lipids. In this paper, we explore the use of Lipomyces yeasts for production of lipids. As the name implies, this clade of yeast have been noted for lipid production in the past, but a systematic survey is lacking. We screened 17 members, made available by the ARS Culture Collection, for lipid production. Three yeasts were discovered to produce lipids as well or better than those reported previously in the literature. Two of these yeasts were further tested for production of lipids on various biomass associated sugars and observed to have lipid yields nearly as good as on glucose. These results are of interest to farmers and producers interested in manufacturing advanced biofuels.

Technical Abstract: Oleaginous yeasts are of interest for production of single cell oils from sugars. Here 17 members of the Lipomyces and Myxozyma clade were screened for lipid production when cultured on glucose. The highest ranking yeasts included L. tetrasporus (21 g/l), L. kononenkoae (19.6 g/l), and L. lipofer (16.7 g/l). By contrast, Rhodosporidium toruloides, which was included as a positive control, produced 16.7 g/l. The L. tetrasporus and L. lipofer were further characterized for growth and lipid production on L-arabinose, xylose, and an equal glucose and xylose mixture. L. tetrasporus had lipid titers of 16.3 – 20.8 g/l and L. lipofer 12.5 – 17.0 g/l. Notable diauxic growth was absent for both strains when grown on a 1:1 glucose and xylose mixture. Lipid contents for the yeasts consisted primarily of C18:1 and C16:0, which is expected to be suitable for biodiesel production.