title: Improvement in Oil Production by Increasing Malonyl-CoA and Glycerol-3-Phosphate Pools in Scenedesmus quadricauda.
abstract: In recent years, microalgae have attracted considerable interest as a biofuel resource owing to their rapid growth, tolerance to harsh conditions, and ability to accumulate a large amount of triacylglycerols (TAGs). However, the economic effectiveness of algal biofuel is still low. In this study, we attempted to increase oil production of the microalga Scenedesmus quadricauda by elevating intracellular malonyl-CoA and glycerol-3-phosphate (G3P) pools. To increase intracellular oil content, yeast-derived genes encoding acetyl-CoA carboxylase (ACC1), glycerol kinase (GPD1), and glycerol-3-phosphate dehydrogenase (GUT1) were overexpressed under the control of CaMV 35S and NOS promoters with SV40 large T antigen components. Fatty acid profiling, G3P content, and the number of cells with high oil content were analyzed by gas chromatography-mass spectrometry, G3P assay kit, and flow cytometry, respectively. Overexpression of ACC1 increased the total fatty acid content by 1.6-fold. Overexpression of GPD1 and GUT1 increased intracellular G3P content by 1.6- and 1.9-fold, respectively. Multi-gene expression of ACC1, GPD1, and GUT1 increased the number of cells with high oil content by 1.45-fold compared with that observed with the wild-type. This study is the first to report increased oil production by overexpression of the key genes (ACC1, GPD1, and GUT1) for TAG biosynthesis in microalgae.
authors.affiliation: Department of Biotechnology, Chonnam National University, Yeosu-si, 550749 Republic of Korea.
authors.forename: Ahmed E
authors.initials: AE
authors.lastname: Gomma
authors.affiliation: Center for Nutraceutical and Pharmaceutical Materials, Myongji University, Yongin-si, 449728 Republic of Korea.
authors.forename: Sung-Kwon
authors.initials: SK
authors.lastname: Lee
authors.affiliation: Department of Biotechnology, Chonnam National University, Yeosu-si, 550749 Republic of Korea.
authors.forename: Sang Mi
authors.initials: SM
authors.lastname: Sun
authors.affiliation: Interdisciplinary Program of Biomodulation, Myongji University, Yongin-si, 449728 Republic of Korea.
authors.forename: Seung Hwan
authors.initials: SH
authors.lastname: Yang
authors.affiliation: Department of Biotechnology, Chonnam National University, Yeosu-si, 550749 Republic of Korea.
authors.forename: Gyuhwa
authors.initials: G
authors.lastname: Chung
keywords: Gene overexpression; Glycerol-3-phosphate content; Microalgae; Oil production; Total fatty acid content