title: Engineering Rhodosporidium toruloides with a membrane transporter facilitates production and separation of carotenoids and lipids in a bi-phasic culture.
abstract: The oleaginous yeast Rhodosporidium toruloides has great biotechnological potential. It accumulates a high amount of lipids which can be used for biofuels and also produces carotenoids which are valuable in the food and pharmaceutical industry. However, the location of these two hydrophobic products in the cell membrane prohibits its efficient harvesting and separation. Here, the transporter Pdr10 was engineered into R. toruloides and cultured in two-phase media containing oil. This enabled the production and in situ export of carotenoids into the oil and concurrent separation from intracellular lipids in the cells. When Pdr10 strain was cultured in the two-phase media, carotenoids and fatty acids yield increased from 1.9 to 2.9 μg/mg and 0.07 to 0.09 mg/mg, respectively. A total of 1.8 μg/mg carotenoids was exported by Pdr10 strain, as compared to 0.3 μg/mg in the wild type. In the Pdr10 strain, the composition of carotenoids and fatty acid it produced also changed. Torulene became the major carotene produced instead of torularhodin. Also, the unsaturated fatty acid C18:2 became the dominant fatty acid produced instead of the saturated C16:0, which was similar to the grape seed oil used in the two-phase media. This indicated that oil was being consumed by the cells, which was supported by the increased intracellular glycerol levels detected by gas chromatography-mass spectrometry (GC-MS). Our approach represents an easy and greener extraction method which could serve to increase the yield and facilitate separation of carotenoids and fatty acids.
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Interdisciplinary Graduate School, Nanyang Technological University, 1 Cleantech Loop, Singapore, 637141, Singapore.
authors.forename: Jaslyn J L
authors.initials: JJ
authors.lastname: Lee
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore, 63745, Singapore.
authors.forename: Liwei
authors.initials: L
authors.lastname: Chen
authors.affiliation: School of Civil and Environmental Engineering and Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 639789, Singapore.
authors.forename: Bin
authors.initials: B
authors.lastname: Cao
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Interdisciplinary Graduate School, Nanyang Technological University, 1 Cleantech Loop, Singapore, 637141, Singapore. WNChen@ntu.edu.sg.|School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore, 63745, Singapore. WNChen@ntu.edu.sg.
authors.forename: Wei Ning
authors.initials: WN
authors.lastname: Chen
mesh_terms: D001487:Basidiomycota / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D056804:Biofuels; D002338:Carotenoids / Q000096:biosynthesis* / Q000302:isolation & purification; D003470:Culture Media / Q000737:chemistry; D005227:Fatty Acids / Q000096:biosynthesis* / Q000302:isolation & purification; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis; D005285:Fermentation; D008401:Gas Chromatography-Mass Spectrometry; D005818:Genetic Engineering; D005990:Glycerol / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics*; D009821:Oils / Q000378:metabolism
chemical_list: D056804:Biofuels; D003470:Culture Media; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D026901:Membrane Transport Proteins; D009821:Oils; D002338:Carotenoids; C078922:torulene; D005990:Glycerol
keywords: ABC transporter; Carotenoids; Extraction; Lipids; Rhodosporidium toruloides; Separation