title: Enhancement of neutral lipid productivity in the microalga Isochrysis affinis Galbana (T-Iso) by a mutation-selection procedure.
abstract: Microalgae offer a high potential for energetic lipid storage as well as high growth rates. They are therefore considered promising candidates for biofuel production, with the selection of high lipid-producing strains a major objective in projects on the development of this technology. We developed a mutation-selection method aimed at increasing microalgae neutral lipid productivity. A two step method, based on UVc irradiation followed by flow cytometry selection, was applied to a set of strains that had an initial high lipid content and improvement was assessed by means of Nile-red fluorescence measurements. The method was first tested on Isochrysis affinis galbana (T-Iso). Following a first round of mutation-selection, the total fatty acid content had not increased significantly, being 262 ± 21 mgTFA (gC)-1 for the wild type (WT) and 269 ± 49 mgTFA (gC)-1 for the selected population (S1M1). Conversely, fatty acid distribution among the lipid classes was affected by the process, resulting in a 20% increase for the fatty acids in the neutral lipids and a 40% decrease in the phospholipids. After a second mutation-selection step (S2M2), the total fatty acid content reached 409 ± 64 mgTFA (gC)-1 with a fatty acid distribution similar to the S1M1 population. Growth rate remained unaffected by the process, resulting in a 80% increase for neutral lipid productivity.
authors.affiliation: IFREMER-PBA, rue de l'Ile d'Yeu, 11 Nantes Cedex 03, France. gael.bougaran@ifremer.fr
authors.forename: Gaël
authors.initials: G
authors.lastname: Bougaran
authors.forename: Catherine
authors.initials: C
authors.lastname: Rouxel
authors.forename: Nolwenn
authors.initials: N
authors.lastname: Dubois
authors.forename: Raymond
authors.initials: R
authors.lastname: Kaas
authors.forename: Sophie
authors.initials: S
authors.lastname: Grouas
authors.forename: Ewa
authors.initials: E
authors.lastname: Lukomska
authors.forename: Jean-René
authors.initials: JR
authors.lastname: Le Coz
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Cadoret
mesh_terms: D005227:Fatty Acids / Q000032:analysis; D005434:Flow Cytometry; D005470:Fluorometry; D058087:Haptophyta / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism* / Q000528:radiation effects; D050356:Lipid Metabolism; D060847:Metabolic Engineering; D009154:Mutation; D012641:Selection, Genetic; D014466:Ultraviolet Rays
chemical_list: D005227:Fatty Acids