title: Selection and identification of oleaginous yeast isolated from soil, animal feed and ruminal fluid for use as feed supplement in dairy cattle.
abstract: The purpose of this study was to select oleaginous yeast for microbial lipid production. Sixty-four yeast isolates were obtained from soil (GSY1-12), animal feeds (FDY1-21), and ruminal fluid (RMY1-31) using yeast extract peptone dextrose (YPD) agar. The cultivation of these isolates on nitrogen limited-medium revealed that GSY2 to GSY6, GSY10, FDY2, FDY12 and FDY14 accumulated lipid over 20% of dry biomass. Therefore, they were preliminarily classified as oleaginous yeast. In subsequent experiment, an 8 × 3 factorial in completely randomized design was conducted to examine the effect of eight oleaginous yeast strains and three nitrogen sources (peptone, (NH4 )2 SO4 , urea) on lipid accumulation when using molasses as substrate. The result illustrated that only GSY3 and GSY10 accumulated lipid over 20% of biomass when using peptone or (NH4 )2 SO4 but urea did not. However, GSY10 gave higher biomass and lipid yield than GSY3 (P < 0·05). Identification of GSY10 using 26S rDNA illustrated that GSY10 belongs to Trichosporon asahii. Fatty acid profiles of this strain contained unsaturated fats up to 62·5% of which oleic acid (C18:1 ) was predominant. In conclusion, T. asahii GSY10 was the most promising oleaginous yeast for microbial lipid production from molasses.
  
  
  CONCLUSIONS
  This study illustrated the ability of T. asahii GSY10 to utilize molasses and (NH4 )2 SO4 for synthesizing and accumulating cellular lipid of which oleic acid (C18:1 ) was predominant. This yeast would be used for microbial lipid production used as feed supplement in dairy cattle.
authors.affiliation: Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: A
authors.identifier: http://orcid.org/0000-0002-0336-3558
authors.initials: A
authors.lastname: Paserakung
authors.affiliation: Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: V
authors.initials: V
authors.lastname: Pattarajinda
authors.affiliation: Department of Biotechnology and Fermentation Research Center for Value Added in Agricultural Products, Faculty of Technology, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: K
authors.initials: K
authors.lastname: Vichitphan
authors.affiliation: Department of Animal and Dairy Science, College of Agricultural and Environmental Science, The University of Georgia, Athens, GA, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Froetschel
mesh_terms: D000645:Ammonium Sulfate / Q000378:metabolism; D000821:Animal Feed / Q000032:analysis / Q000382:microbiology*; D000818:Animals; D018533:Biomass; D002417:Cattle; D004275:DNA, Ribosomal / Q000235:genetics; D019587:Dietary Supplements; D008965:Molasses / Q000382:microbiology*; D009584:Nitrogen / Q000378:metabolism; D019301:Oleic Acid / Q000096:biosynthesis* / Q000378:metabolism; D010461:Peptones / Q000378:metabolism; D012335:RNA, Ribosomal / Q000235:genetics; D012417:Rumen / Q000382:microbiology; D012987:Soil; D012988:Soil Microbiology; D014250:Trichosporon / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014508:Urea / Q000378:metabolism
chemical_list: D004275:DNA, Ribosomal; D010461:Peptones; D012335:RNA, Ribosomal; C065096:RNA, ribosomal, 26S; D012987:Soil; D019301:Oleic Acid; D014508:Urea; D009584:Nitrogen; D000645:Ammonium Sulfate
keywords: Trichosporon asahii; dairy cattle; feed supplement; microbial lipid; molasses