CRISPR: A Solution to the Global Energy Crisis?

Biofuel is the combustible fuel obtained from biomass, and are either first or second generation biofuels. First generation biofuels are unprocessed organic materials such as wood chips & pellets used for cooking or generating electricity. Second generation biofuels are processed and liquified and include ethanol and biodiesel.

Biofuel is produced either through a fermentation process, or a chemical reaction. The type of biofuel produced depends on the processing of the biomass. For example, ethanol is a by-product of the fermentation processes of plant sugars whereas biodiesel is produced as a result of a chemical reaction between greases with alcohol.

Recently, scientists have used a novel approach of tweaking bacteria and algae using CRISPR to produce biofuels. With this process, CRISPR is adding to the uses of biofuels, and radically transforming the energy sector!

CRISPR has made it possible to produce double the amount of biodiesel from phototropic algae—a concept that scientists have been attempting to optimize since the 1970s. A team of researchers from California have found a way of doubling the lipid production in algae, using CRISPR to tweak the genes.

Algae are tiny, slimy organisms that reek of fish! These organisms, like plants, need sunlight, carbon dioxide, and other nutrients such as nitrogen and phosphorus to survive. If you put them on an extreme diet (starve them of the essential nutrients), they start storing energy.

Instead of growing and multiplying, they become sluggish, go into a dormant stage, and start building up fatty lipids. Scientists identified 20 transcription factors that regulate lipid production in algae. They then used CRISPR to knock out 18 of these, and were able to double the lipid production in algae.

This research was a collaboration between companies ExxonMobil and Synthetic Genomics, both aiming to advance biofuel energy research. The companies recently announced that a new phase of their research program could lead to the generation of 10,000 barrels of algae biofuel per day by 2025!

Yeast are powerful model organisms often used in industrial production. However, the stress of excessive protein or metabolite generation impacts the organisms during the bioproduction cycle. Pre-treatment chemicals that are used to speed up the process of cellulose breakdown into sugars are also potentially harmful to yeast.

Yeast plays an important role in the fermentation of the sugars to biofuels. Researchers have now found a way to protect yeast from damage during the biofuel production process using CRISPR. The research team made two changes to a single gene such that yeast is now tolerant to these pre-treatment chemicals!

Clostridium autoethanogenum is an acetogenic microbe used for gas fermentation. This tiny organism can be used for the commercial scale production of ethanol. However, commercial exploitation of acetogenic microbes is challenging, as scientists only have a basic understanding of it, and there is limited availability of genetic tools and high-throughput engineering platforms. In a recent study, CRISPR has shown improved efficiency of gene-deletion in this bacteria, making it a viable tool for engineering this tiny organism!