title: Screening of the entire USDA castor germplasm collection for oil content and fatty acid composition for optimum biodiesel production.
abstract: Castor has tremendous potential as a feedstock for biodiesel production. The oil content and fatty acid composition in castor seed are important factors determining the price for production and affecting the key fuel properties of biodiesel. There are 1033 available castor accessions collected or donated from 48 countries worldwide in the USDA germplasm collection. The entire castor collection was screened for oil content and fatty acid composition by nuclear magnetic resonance (NMR) and gas chromatography (GC), respectively. Castor seeds on the average contain 48.2% oil with significant variability ranging from 37.2 to 60.6%. Methyl esters were prepared from castor seed by alkaline transmethylation. GC analysis of methyl esters confirmed that castor oil was composed primarily of eight fatty acids: 1.48% palmitic (C16:0), 1.58% stearic (C18:0), 4.41% oleic (C18:1), 6.42% linoleic (C18:2), 0.68% linolenic (C18:3), 0.45% gadoleic (C20:1), 84.51% ricinoleic (C18:1-1OH), and 0.47% dihydroxystearic (C18:0-2OH) acids. Significant variability in fatty acid composition was detected among castor accessions. Ricinoleic acid (RA) was positively correlated with dihydroxystearic acid (DHSA) but highly negatively correlated with the five other fatty acids except linolenic acid. The results for oil content and fatty acid composition obtained from this study will be useful for end-users to explore castor germplasm for biodiesel production.
authors.affiliation: Plant Genetic Resources Conservation Unit, Agricultural Research Service, U.S. Department of Agriculture, Griffin, Georgia 30223, United States. mingli.wang@ars.usda.gov
authors.forename: Ming Li
authors.initials: ML
authors.lastname: Wang
authors.forename: J Bradley
authors.initials: JB
authors.lastname: Morris
authors.forename: Brandon
authors.initials: B
authors.lastname: Tonnis
authors.forename: David
authors.initials: D
authors.lastname: Pinnow
authors.forename: Jerry
authors.initials: J
authors.lastname: Davis
authors.forename: Paul
authors.initials: P
authors.lastname: Raymer
authors.forename: Gary A
authors.initials: GA
authors.lastname: Pederson
mesh_terms: D056804:Biofuels; D002367:Ricinus communis; D002368:Castor Oil / Q000032:analysis*; D002849:Chromatography, Gas; D005227:Fatty Acids / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D012277:Ricinoleic Acids / Q000032:analysis; D012639:Seeds / Q000737:chemistry*; D014481:United States; D016885:United States Department of Agriculture
chemical_list: D056804:Biofuels; D005227:Fatty Acids; D012277:Ricinoleic Acids; D002368:Castor Oil; C030521:ricinoleic acid