Genetic engineering of microalgae lipid biosynthesis for sustainable biodiesel production

Biofuel is one of the most promising alternative energy sources for reducing human reliance on fossil fuels. Microalgae has recently emerged as the most promising biofuel source. However, biofuels from microalgae are still not feasible to replace fossil fuels because of their high production costs, therefore, it is necessary to pick microalgae species with high growth rates and lipid content. Overexpression of lipid biosynthesis enzymes and inhibition of competitive metabolic pathways are two genetic engineering strategies that can be developed to assess microalgae lipid production. Malate and multienzyme enzymes (GPAT, LPAAT and DGAT) can be overexpressed in microalgae to boost lipid production. The strategy of blocking competitive metabolic pathways can be carried out through suppression of starch metabolism and lipid catabolism. The strategy of blocking competitive metabolic pathways has been carried out in several microalgae and is effective for enhancing lipid biosynthesis. Several mutations that block both the starch metabolic and lipid catabolic pathways can result in increased levels of microalgal lipid accumulation.