Photo credit: Chris Calvey and Thomas Jeffries, USDA Forest Service, Forest Products Laboratory

Lipomyces starkeyi NRRL Y-11557* is an ascomycetous yeast belonging to the order Saccharomycetales. It is known in its telomorphic form with no known anomorphic connections. L. starkeyi NCYC 1436 has been reported to have eleven chromosome-sized DNA molecules ranging from 0.7 to 2.8 kb and a total estimated genome of 15 Mb (4). Most notably from the perspective of biological energy production, L. starkeyi can form more than 60% of its cell dry weight under optimal conditions of carbon source, yeast extract and ferrous sulfate. Lipid production is maximal when glucose and xylose are supplied in a ratio of approximately 2:1 (12). L. starkeyi will produce lipids from various sugars, whey permeate (2), and even sewage sludge (3). Temperature affects lipid composition with the highest lipid production rate reported at 28˚C (10, 11). Fatty acid analysis of cells grown on whey permeate showed palmitic, stearic, oleic and linoleic acid; as the predominant fatty acids in the triacylglycerol fractions. The phospholipid fractions were dominated by oleic and linoleic acids (1). L. starkeyi forms multiple alpha-amylases (6, 9), dextranase, (7), glucanohydrolase (8)and levoglucosan kinase activities, the latter of which converts this cellulolytic pyrolysate into glucose-6-phosphate (5).

1. Akhtar, P., J. I. Gray, and A. Asghar. 1998. Chemical characterization and stereospecific analysis of lipids synthesized by certain yeast strains. Journal of Food Lipids 5:299-311.

2. Akhtar, P., J. I. Gray, and A. Asghar. 1998. Synthesis of lipids by certain yeast strains grown on whey permeate. Journal of Food Lipids 5:283-297.

3. Angerbauer, C., M. Siebenhofer, M. Mittelbach, and G. M. Guebitz. 2008. Conversion of sewage sludge into lipids by Lipomyces starkeyi for biodiesel production. Bioresource Technology 99:3051-3056.

4. Bignell, G. R., I. J. Bruce, and I. H. Evans. 1996. Electrophoretic karyotype of the amylolytic yeast Lipomyces starkeyi and cloning, sequencing and chromosomal localization of its TRP1 gene. Current Genetics 30:83-88.

5. Dai, J. H., Z. S. Yu, Y. Z. He, L. Zhang, Z. H. Bai, Z. Y. Dong, Y. G. Du, and H. X. Zhang. 2009. Cloning of a novel levoglucosan kinase gene from Lipomyces starkeyi and its expression in Escherichia coli. World Journal of Microbiology & Biotechnology 25:1589-1595.

6. Kang, H. K., J. H. Lee, D. Kim, D. F. Day, J. F. Robyt, K. H. Park, and T. W. Moon. 2004. Cloning and expression of Lipomyces starkeyi alpha-amylase in Escherichia coli and determination of some of its properties. Fems Microbiology Letters 233:53-64.

7. Kang, H. K., J. Y. Park, J. S. Ahn, S. H. Kim, and D. Kim. 2009. Cloning of a Gene Encoding Dextranase from Lipomyces starkeyi and its Expression in Pichia pastoris. Journal of Microbiology and Biotechnology 19:172-177.

8. Kim, D., S. J. Ryu, E. J. Son, H. J. Chung, S. H. Kim, D. W. Kim, and D. F. Day. 2002. Glucanhydrolase from Lipomyces starkeyi KSM 22 as potential mouthwash ingredient. Journal of Microbiology and Biotechnology 12:993-997.

9. Millson, S. H., and I. H. Evans. 2007. Multiple dextranases from the yeast Lipomyces starkeyi. Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology 92:399-404.

10. Suutari, M., P. Priha, and S. Laakso. 1993. Temperature shifts in regulation of lipids accumutaed by Lipomyces starkeyi. Journal of the American Oil Chemists Society 70:891-894.

11. Suutari, M., A. Rintamaki, and S. Laakso. 1996. The effect of temperature on lipid classes and their fatty acid profiles in Lipomyces starkeyi. Journal of the American Oil Chemists Society 73:1071-1073.

12. Zhao, X., X. L. Kong, Y. Y. Hua, B. Feng, and Z. B. Zhao. 2008. Medium optimization for lipid production through co-fermentation of glucose and xylose by the oleaginous yeast Lipomyces starkeyi. European Journal of Lipid Science and Technology 110:405-412.

* NRRL Y-11557 =ATCC 58680=CBS 1807=CCRC 21522=DSM 70295=IFO 1289=JCM 5995=NRRL Y-1388=Starkey strain 74