Nuclear Transformation of the Green Microalga Chlorella saccharophila for the Overexpression of Triacylgliceride Metabolism Genes

Chlorella saccharophila is a freshwater green microalga that can be found in different environments around the world. Previously we studied the biomass accumulation, lipid content and productivity, as well as the fatty acid methyl esters (FAME) profile of a strain of C. saccharophila native from the Yucatan Peninsula, in Mexico. From this study, we suggested that this microalga was a suitable source of lipids for biodiesel production (Herrera-Valencia et al. 2011). In order to attain the economic feasibility at an industrial scale of microalgae for biodiesel production, it is necessary to further improve lipid yields, particularly triacylgliceride (TAG) accumulation in these microorganisms. However, the metabolic pathways involved in TAG synthesis are not fully understood in microalgae. We have identified genes from the green microalga Chlamydomonas reinhardtii that could be involved in TAG synthesis, and we are interested in investigating the overexpression of these genes and their effect in TAG synthesis in a highly productive and lipid-rich microalga strain as C. saccharophila. Therefore, the aim of the present study is to develop a nuclear transformation protocol for C. saccharophila and use this system to overexpress genes involved in lipid metabolism. The results of the present study may lead to enhance the level of TAGs in C. saccharophila for biodiesel production.