Strategies in Genetic Engineering of Microalgae for High-Lipid Production

Fossil energy crisis and global climate change are two major challenges in the 21st century. Biodiesel, as an environmentally friendly and renewable alternative energy source to petroleum diesel, has drawn worldwide attention. Compared with vegetable oil and animal fats, algal lipid is considered to be one of future biodiesel feedstocks because of the microalgae characterized in its easy cultivation and high lipid content. The genetic engineering has now become a new research hotpoint to enhance the lipid metabolism pathway, thus to improve the lipid content of oil-rich microalgae. In this paper, the advances of lipid biosynthesis pathway in microalgae, and the metabolic regulation strategies for increasing lipid accumulation are reviewed. The importance of Kennedy pathway enhancement in the microalgal TAG biosynthesis is elaborated based on the fact that the enhanced glycerol acyltransferase expression in plants can increase the metabolism of Kennedy pathway intermediates flux, thereby increasing the triacylglycerols (TAG) accumulation. The current genetic transformation methods of microalgae and their key scientific and technical issues, as well as the possibility and prospects of genetic engineering metabolic pathways to regulate the microalgae lipid production are further discussed in detail.