Abstract
Microalgae are ideal raw materials for biodiesel and bioactive compounds. Glycerol-3-phosphate is formed from dihydroxyacetone phosphate (DHAP) through the glycolytic pathway catalyzed by glycerol-3-phosphate dehydrogenase (GPDH). GPDH was characterized in the marine diatom Phaeodactylum tricornutum. In the GPDH-overexpressing P. tricornutum cells, the glycerol concentration per cell in the transformed diatom increased by 6.8-fold compared with the wild type, indicating that the overexpression of GPDH promoted the conversion of DHAP to glycerol-3-phosphate. There was a 60% increase in neutral lipid content, reaching 39.7% of dry cell weight in transgenic cells in the stationary phase, despite a 20% decrease in cell concentration. Fatty acid profiling showed that the levels of 16- and 18-carbon monounsaturated fatty acids significantly increased. GPDH had a significant impact on numerous metabolic processes in diatom cells, including the biosynthesis of glycerol and neutral lipids. These findings are instructive for the metabolic engineering of microalgae for biofuel production.
Highlights
Microalgae are ideal raw materials for biodiesel and bioactive compounds
Sequence prediction of glycerol-3-phosphate dehydrogenase (GPDH) The putative GPDH gene of P. tricornutum (GenBank accession: XP_002177310.1) was obtained by BLAST searching on NCBI, based on the GPDH gene of S. cerevisiae (GenBank accession number Z24454)
The mRNA expression of the GPDH gene was demonstrated by quantitative PCR (Figure 2B)
Summary
Microalgae are ideal raw materials for biodiesel and bioactive compounds. Glycerol-3-phosphate is formed from dihydroxyacetone phosphate (DHAP) through the glycolytic pathway catalyzed by glycerol-3-phosphate dehydrogenase (GPDH). It has become increasingly clear that conventional fossil fuels, such as coal, petroleum, and natural gas, are not sustainable in respect to operational efficiency and environmental impact due to the requirement for enormous consumption of these fuels and the greenhouse gas emissions caused by them [1]. To solve the problem of energy supply and environmental concerns caused by the consumption of fossil fuels, alternative renewable biofuels must be developed [2,3]. Vegetable oils and animal fats were the first generation of biofuels [4], but these still cannot meet the growing demand from the rapidly developing world. In many marine microalgae species, lipids are the major storage metabolite and are generally seen in the form of triacylglycerols (TAGs) stored in oil bodies. Microalgae are considered a promising candidate for renewable biofuel production [6,7]
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