title: Comparison of Biochemical Activities between High and Low Lipid-Producing Strains of Mucor circinelloides: An Explanation for the High Oleaginicity of Strain WJ11.
abstract: The oleaginous fungus, Mucor circinelloides, is one of few fungi that produce high amounts of γ-linolenic acid (GLA); however, it usually only produces <25% lipid. Nevertheless, a new strain (WJ11) isolated in this laboratory can produce lipid up to 36% (w/w) cell dry weight (CDW). We have investigated the potential mechanism of high lipid accumulation in M. circinelloides WJ11 by comparative biochemical analysis with a low lipid-producing strain, M. circinelloides CBS 277.49, which accumulates less than 15% (w/w) lipid. M. circinelloides WJ11 produced more cell mass than that of strain CBS 277.49, although with slower glucose consumption. In the lipid accumulation phase, activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in strain WJ11 were greater than in CBS 277.49 by 46% and 17%, respectively, and therefore may provide more NADPH for fatty acid biosynthesis. The activities of NAD+:isocitrate dehydrogenase and NADP+:isocitrate dehydrogenase, however, were 43% and 54%, respectively, lower in WJ11 than in CBS 277.49 and may retard the tricarboxylic acid cycle and thereby provide more substrate for ATP:citrate lyase (ACL) to produce acetyl-CoA. Also, the activities of ACL and fatty acid synthase in the high lipid-producing strain, WJ11, were 25% and 56%, respectively, greater than in strain CBS 277.49. These enzymes may therefore cooperatively regulate the fatty acid biosynthesis in these two strains.
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, P.R. China.
authors.forename: Xin
authors.initials: X
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, P.R. China; Synergistic Innovation Center for Food Safety and Nutrition, Wuxi, P.R. China.
authors.forename: Haiqin
authors.initials: H
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, P.R. China; Synergistic Innovation Center for Food Safety and Nutrition, Wuxi, P.R. China.
authors.forename: Yong Q
authors.initials: YQ
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, P.R. China; Synergistic Innovation Center for Food Safety and Nutrition, Wuxi, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: Departamento de Genética y Microbiología (Unidad asociada al IQFR-CSIC), Facultad de Biología, Universidad de Murcia, Murcia, Spain.
authors.forename: Victoriano
authors.initials: V
authors.lastname: Garre
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, P.R. China.
authors.forename: Yuanda
authors.initials: Y
authors.lastname: Song
authors.affiliation: Department of Biological Sciences, University of Hull, Hull, United Kingdom.
authors.forename: Colin
authors.initials: C
authors.lastname: Ratledge
mesh_terms: D001275:ATP Citrate (pro-S)-Lyase / Q000378:metabolism; D000105:Acetyl Coenzyme A / Q000378:metabolism; D018533:Biomass; D002849:Chromatography, Gas; D005227:Fatty Acids / Q000032:analysis / Q000096:biosynthesis; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D007521:Isocitrate Dehydrogenase / Q000378:metabolism; D008055:Lipids / Q000032:analysis; D009089:Mucor / Q000201:enzymology / Q000378:metabolism*; D009249:NADP / Q000378:metabolism; D010734:Phosphogluconate Dehydrogenase / Q000378:metabolism; D017965:gamma-Linolenic Acid / Q000378:metabolism*
chemical_list: D005227:Fatty Acids; D008055:Lipids; D009249:NADP; D000105:Acetyl Coenzyme A; D017965:gamma-Linolenic Acid; D007521:Isocitrate Dehydrogenase; D010734:Phosphogluconate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase; D001275:ATP Citrate (pro-S)-Lyase