How Can CRISPR Revolutionize Environmental Science?

CRISPR allows scientists to edit genes, significantly cutting and pasting at targeted sites. But this essential ability makes CRISPR an excellent tool for complex genetic engineering.

Fremont, CA: Complex environmental challenges will become much more feasible in the CRISPR age of genetic engineering.

1. BIOFUELS

Plants, algae and cyanobacteria naturally convert carbon dioxide and sunlight into byproducts. The sugars, fats or alcohols formed are all potential replacement fuel sources. Scientists have proved that CRISPR works in specific species of cyanobacteria, algae and several main biofuel crops.

Bacteria can also collapse plant cell walls into biofuels, and specific species can produce fuel precursors from waste products, like methane from landfills. CRISPR has been used on critical bacteria that naturally contain some pathways essential for producing biofuels.

Acquiring these organisms to grow happily while churning fuel precursors is not trivial. However, the precision and efficiency of CRISPR allow for the type of complex genetic engineering that could aid make biofuels a viable alternative.

2.BIOPLASTICS

Fuels aren't just petroleum-based products that could someday be replaced by biology. For example, specific yeast and bacteria naturally make compounds similar to plastics. CRISPR could support making these compounds more plenteous and easier to extract.

3. BIOREMEDIATION

Microbes could also be engineered to support degraded plastics. Particular species of bacteria and fungi have evolved naturally to degrade compounds found in plastics. CRISPR could be used to increase the activity of the genetic pathways involved. Scientists have already started applying CRISPR to microbes that are good candidates for producing and degrading plastics.

There are many other sorts of bioremediation where CRISPR might prove handy. For example, microbes or plants could be engineered to take up heavy metals more efficiently, clean up oil spills, or improve wastewater treatment.

4. BIOSENSING

Biosensing goes side by side with bioremediation. In biosensing, probes or sensors discover the presence of specific molecules.

Plants and microbes work as natural biosensors, responding to chemicals in their environment. These detection and response pathways can be re-engineered.

Work on engineering plants that notice and signal the presence of bioweapons and pathogens is ongoing. Similarly, plants or other organisms could identify environmental pollutants.

Once a pollutant is detected, the biosensor could trigger a bioremediation pathway. CRISPR has made this complex multi-gene network engineering in plants much more feasible.

5. GREENHOUSE GAS EMISSIONS

By decreasing our dependence on fossil fuels, CRISPR could help address biological sources of greenhouse gas emissions. For example, burning fossil fuels releases much carbon dioxide into the environment. But atmospheric methane, a far stronger greenhouse gas, is thought to come mainly from bacteria.

Some bacteria come from natural sources like wetlands; others live in cows' guts and flooded rice fields. By refining the genetics of cows or the grass they eat, cattle ranches might produce fewer belches per beef in the future. Rice can also be engineered to check bacterial growth and support keeping more methane in the ground. CRISPR could encourage these efforts by enhancing the speed and accuracy of the genetic engineering process.

6. PESTICIDE REDUCTION

Through CRISPR, plants can be engineered to defy threats such as insects or diseases. For example, CRISPR has already helped generate virus-resistant cucumbers and fungus-resistant rice. Sometimes, pesticides are the only other way to keep these threats from destroying our food supply.

7. EFFICIENT WATER USE

Agriculture is evaluated to use up to 70% of the world's freshwater resources. Several studies have already found that CRISPR can help make plants more water-efficient or improve our understanding of what genes are essential for drought tolerance.

8. NITROGEN FIXATION

Nitrogen runoff is another agriculturally applicable environmental problem. Plants cannot promptly take up most forms of nitrogen in the soil. Instead, certain plants, such as beans and peas, develop associations with bacteria that help make soil nitrogen more available to the plant.

Others depend on added nitrogen in the form of manure or synthetic fertilizer.

Excess added nitrogen could run off fields and contaminate water sources, leading to aquatic dead zones. As a result, many current projects are underway using CRISPR to engineer plants or bacteria for improved nitrogen fixation.

9. INVASIVE SPECIES

Animal or plant species carried from one region to another can wreak havoc on native ecosystems. There are many different genetic strategies for eliminating invasive species. These incorporate "gene drives," in which a gene that decreases fitness is spread through the population. Researchers have already described several CRISPR-based gene drive strategies. In addition, CRISPR could also be applied to "self-limiting" technologies, which act like a genetic form of birth control.