Document Type : Research Paper
Microalgal Molecular Genetics and Functional genomics Special Research Unit, Department of Genetics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.
Center for Advanced Studies in Tropical Natural Resources, National Research University-Kasetsart University (CASTNAR, NRU-KU), Kasetsart University, Bangkok 10900, Thailand.
Department of Botany, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.
Biodiesel and natural products derived from microalgae require a smaller land area and have higher production rates compared to plants and animals and has recently attracted considerable interest. However, biodiesel production from microalgal triacylglycerol is still far from commercial realization due to its high production cost. One way to overcome this obstacle is to improve the triacylglycerol accumulation and couple its production with other high-value compounds. Of particular interest is the sterol biosynthetic pathway with squalene as an intermediate due to its close relationship with triacylglycerol and carotenoid biosynthetic pathways. Besides, both squalene and carotenoids are isoprenoid lipids that have health benefits. Perturbation of one pathway has been suggested to affect other pathways. Three terbinafine-sensitive mutants of the green microalga Chlamydomonas reinhardtii were isolated using terbinafine, a drug that inhibits squalene epoxidase, leading to squalene accumulation.One of the mutants, tfs2, accumulated twice the amount of wild-type triacylglycerol. As well as squalene accumulation, the presence of terbinafine further increased the triacylglycerol content. The level of prenyl lipid carotenoid and chlorophyll was also more significant than that of the wild type. Growth and photosynthesis were not compromised in this mutant. This is the first study that has demonstrated amutant screening method to improve the co-production of TAG and isoprenoid lipids in a green microalga.
- A mutant screening method for improving triacylglycerol (TAG) and isoprenoid content.
- Terbinafine-sensitive mutants were isolated in Chlamydomonas.
- One mutant exhibited 2X higher level of triacylglycerol and 1.5X higher level of photosynthetic pigments.
- The presence of terbinafine further increased the triacylglycerol level along with the accumulation of squalene.
- The mutant exhibited normal growth and photosynthesis.