Novel Molecular Tools for Metabolic Engineering to Improve Microalgae-Based Biofuel Production

Abstract

Biofuels are derived from biological material. They are an environmentally friendly, low-cost, and renewable energy source, making them potential fuels to replace nonrenewable fossil fuel. Over time, biofuel production technology/methodology has gone through several generations, from the simplest means of production (conversion of simple sugars into biofuel) to the current, more complicated means of production (using novel plant biotechnology). The next generation of biofuel production will involve genetic engineering to improve yields, especially metabolic pathway engineering. Both macroalgae and microalgae sources offer an alternative to fossil-based fuels. Single-celled microalgae use carbon dioxide and sunlight to produce energy. They provide an attractive alternative, due to the significance of their lipid yield, which can be further processed into biofuels and valuable coproducts. The use of microalgae to produce biofuels reduces overall carbon emission without taking away the lands needed for food crops. Despite vigorous research, deployment of large-scale algae-based biofuel production still faces challenges, including high demands of input (water, nutrients, CO₂, etc.) for algal growth. Genetic engineering of algal metabolic pathways holds potential for generating high lipid yields with minimal input. In this chapter, we discuss the use of modern molecular tools for metabolic engineering to improve microalgae-based biofuel production. These include multiple gene transformation, site-specific gene stacking, and precise gene/allele modification with currently developed genome-editing technology, such as CRISPR/Cas9 system.