title: Nitrogen limitation, oxygen limitation, and lipid accumulation in Lipomyces starkeyi.
abstract: Lipid production by oleaginous yeasts is optimal at high carbon-to-nitrogen ratios. In the current study, nitrogen and carbon consumption by Lipomyces starkeyi were directly measured in defined minimal media with nitrogen content and agitation rates as variables. Shake flask cultures with an initial C:N ratio of 72:1 cultivated at 200rpm resulted in a lipid output of 10g/L, content of 55%, yield of 0.170g/g, and productivity of 0.06g/L/h. All of these values decreased by ≈50-60% when the agitation rate was raised to 300rpm or when the C:N ratio was lowered to 24:1, demonstrating the importance of these parameters. Under all conditions, L. starkeyi cultures tolerated acidified media (pH≈2.6) without difficulty, and produced considerable amounts of alcohols; including ethanol, mannitol, arabitol, and 2,3-butanediol. L. starkeyi also produced lipids from a corn stover hydrolysate, showing its potential to produce biofuels from renewable agricultural feedstocks.
authors.affiliation: Department of Bacteriology, University of Wisconsin - Madison, 1531 Microbial Sciences Building, 1550 Linden Drive, Madison, WI 53706, United States; Great Lakes Bioenergy Research Center, University of Wisconsin - Madison, Madison, WI 53726, United States.
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Calvey
authors.affiliation: Department of Bacteriology, University of Wisconsin - Madison, 1531 Microbial Sciences Building, 1550 Linden Drive, Madison, WI 53706, United States; Great Lakes Bioenergy Research Center, University of Wisconsin - Madison, Madison, WI 53726, United States.
authors.forename: Yi-Kai
authors.initials: YK
authors.lastname: Su
authors.affiliation: Department of Bacteriology, University of Wisconsin - Madison, 1531 Microbial Sciences Building, 1550 Linden Drive, Madison, WI 53706, United States; Great Lakes Bioenergy Research Center, University of Wisconsin - Madison, Madison, WI 53726, United States; Institute for Microbial and Biochemical Technology, Forest Products Laboratory, USDA Forest Service, Madison, WI 53726, United States.
authors.forename: Laura B
authors.initials: LB
authors.lastname: Willis
authors.affiliation: Great Lakes Bioenergy Research Center, University of Wisconsin - Madison, Madison, WI 53726, United States.
authors.forename: McSean
authors.initials: M
authors.lastname: McGee
authors.affiliation: Department of Bacteriology, University of Wisconsin - Madison, 1531 Microbial Sciences Building, 1550 Linden Drive, Madison, WI 53706, United States; Great Lakes Bioenergy Research Center, University of Wisconsin - Madison, Madison, WI 53726, United States; Institute for Microbial and Biochemical Technology, Forest Products Laboratory, USDA Forest Service, Madison, WI 53726, United States. Electronic address: twjeffri@wisc.edu.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Jeffries
mesh_terms: D000332:Aerobiosis / Q000187:drug effects; D000641:Ammonia / Q000378:metabolism; D056804:Biofuels; D002244:Carbon / Q000032:analysis; D005227:Fatty Acids / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D050356:Lipid Metabolism / Q000187:drug effects*; D008055:Lipids / Q000096:biosynthesis*; D055160:Lipomyces / Q000187:drug effects / Q000378:metabolism*; D009584:Nitrogen / Q000494:pharmacology*; D010100:Oxygen / Q000494:pharmacology*; D011108:Polymers / Q000378:metabolism; D064210:Secondary Metabolism / Q000187:drug effects; D014866:Waste Products; D003313:Zea mays / Q000737:chemistry
chemical_list: D056804:Biofuels; D005227:Fatty Acids; D008055:Lipids; D011108:Polymers; D014866:Waste Products; C024617:polyol; D002244:Carbon; D000641:Ammonia; D009584:Nitrogen; D010100:Oxygen
keywords: Aeration; C:N ratio; Hydrolysate; Oleaginous yeast; Polyols