title: Expression of the heterologous Dunaliella tertiolecta fatty acyl-ACP thioesterase leads to increased lipid production in Chlamydomonas reinhardtii.
abstract: Biofuel production from genetically-engineered microalgae is currently among the most widely studied strategies in generating renewable energy. However, microalgae currently suffer from low oil yields which limit the commercial feasibility of industrial-scale production. A major bottleneck in cost-efficient biofuel production from microalgae is the dilemma between biomass productivity and lipid accumulation. When grown under stressful culture conditions such as nitrogen depletion, microalgae accumulate large amounts of neutral lipids, but it comes at the expense of growth which negatively impacts overall lipid productivity. Overexpression of acyl-ACP thioesterases (TE) had been successful in increasing the production of fatty acids (FA) in prokaryotes such as E. coli and cyanobacteria, but has not been effectively tested in microalgae. In this study, we introduced a TE from D. tertiolecta (DtTE) into C. reinhardtii to investigate its effects on FA production without compromising growth. The results indicate that C. reinhardtii transformants were able to produce 63 and 94% more neutral lipids than the wild-type, which translates to an approximately 56% improvement in total lipids, without compromising growth. These findings demonstrate the cross-species functionality of TE, and provide a platform for further studies into using TE as a strategy to increase biofuel production from microalgae.
authors.affiliation: Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545.
authors.forename: Kenneth Wei Min
authors.initials: KW
authors.lastname: Tan
authors.affiliation: Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545. Electronic address: yuan_kun_lee@nuhs.edu.sg.
authors.forename: Yuan Kun
authors.initials: YK
authors.lastname: Lee
mesh_terms: D020418:Algal Proteins / Q000235:genetics / Q000378:metabolism; D018533:Biomass; D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D000460:Chlorophyta / Q000235:genetics / Q000378:metabolism*; D005818:Genetic Engineering; D008055:Lipids / Q000096:biosynthesis*; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013869:Thiolester Hydrolases / Q000235:genetics* / Q000378:metabolism
chemical_list: D020418:Algal Proteins; D008055:Lipids; D013869:Thiolester Hydrolases; C018748:oleoyl-(acyl-carrier-protein) hydrolase
keywords: Chlamydomonas reinhardtii; Dunaliella tertiolecta; Fatty acid; Lipid; Thioesterase; acyl-ACP