Genetic Engineering of Algae for Enhanced Biofuel Production

Abstract

2There are currently intensive global research efforts aimed at increasing and modifying the accumulation of lipids, alcohols, hydrocarbons, polysaccharides, and other energy storage compounds in photosynthetic organisms, yeast, and bacteria through genetic engineering. Many improvements have been realized, including increased lipid and carbohydrate production, improved H 2 yields, and the diversion of central metabolic intermediates into fungible biofuels. Photosynthetic microorganisms are attracting considerable interest within these efforts due to their relatively high photosynthetic conversion efficiencies, diverse metabolic capabilities, superior growth rates, and ability to store or secrete energy-rich hydrocarbons. Relative to cyanobacteria, eukaryotic microalgae possess several unique metabolic attributes of relevance to biofuel production, including the accumulation of significant quantities of triacylglycerol; the synthesis of storage starch (amylopectin and amylose), which is similar to that found in higher plants; and the ability to efficiently couple photosynthetic electron transport to H 2 production. Although the application of genetic engineering to improve energy production phenotypes in eukaryotic microalgae is in its infancy, significant advances in the development of genetic manipulation tools have recently been achieved with microalgal model systems and are being used to manipulate central carbon metabolism in these organisms. It is likely that many of these advances can be extended to industrially relevant organisms. This review is focused on potential avenues of genetic engineering that may be undertaken in order to improve microalgae as a biofuel platform for the production of biohydrogen, starch-derived alcohols, diesel fuel surrogates, and/or alkanes.

Transcript level coordination of carbon pathways during silicon starvation‐induced lipid accumulation in the diatom Thalassiosira pseudonana

“…A more complete understanding of the significance of transcriptional control of cellular processes is important for an improved understanding of the basic biology of diatoms and other microalgae, and has implications for environmental and biotechnological studies. For example, metabolic engineering to improve lipid productivity is widely considered to be an essential element of economic feasibility and commercialization of algae as a feedstock for renewable biofuels (Radakovits et al ., 2010; Davis et al ., 2011). Appropriate selection of targets for effective genetic engineering is required to accomplish these tasks.…”

Increasing Microbial Biofuel Production by In-silico Comparative Genomic Studies

“… The ability to thrive in diverse ecosystems Although microalgae have long been considered a promising feedstock for the production of biofuels, studies have concluded that the economic viability of microalgal biofuel production is in need of significant improvement. However, in contrast to previous efforts, we are now equipped with an arsenal of new genetic tools, genome sequences, and high-throughput analytical techniques that will equip and empower scientists to analyze and manipulate metabolic pathways with unrivaled precision [6].…”

“…They are an extremely diverse group of organisms, many of which possess unique metabolic features that can be altered for the production of renewable biofuels [6]. These include:  High efficiency of conversion during photosynthesis.…”

“…Microalgae are especially attractive as a source of fuel from an environmental standpoint because they consume carbon dioxide and can be grown on marginal land, using waste or salt water [6]. In addition, it may be possible to leverage the metabolic pathways of microalgae to produce a wide variety of biofuels (see Fig.…”

“…Researchers have been exploiting algae for biodiesel production due to their short life cycle, less labor required, less affection by venue, and easier scale up procedure [5]. Several species have biomass production rates that can surpass those of terrestrial plants, and many eukaryotic microalgae have the ability to store significant amounts of energy-rich compounds, such as triacylglycerol (TAG) and starch, which can be utilized for the production of several distinct biofuels, including biodiesel and ethanol [6]. Fatty acids are also important precursors to biofuel [7].…”