Amid Oil Price Crash, a New Hope for Biofuels

Long before the COVID-19 crisis hit, the biofuels industry had to answer questions of competitiveness, scale, and impact on land resources. Those questions have been thrown into stark relief now that oil and gas prices have crashed. However, there are reasons to be optimistic about the future of biofuels, as the field continues to evolve remarkably from where it was a decade ago.

Tearing down the plant cell walls for better biofuels

One key development in the biofuels sector involves reshaping basic perceptions about biofuel crops.

Biofuel researchers initially focused on using enzymes to convert the softer, starchy parts of food crops — corn kernels, for example — into glucose, and then into ethanol.

The next step seems logical enough. Rather than letting the rest of the plant go to waste, the focus has turned to developing enzymes that can break down cellulose, the main component of cell walls. That approach also provides for greater use of non-food crops.

The problem is that cell walls also contain lignin, which interferes with enzymes. That opens the door to a third stage, as researchers engineer plants with more cellulose and less lignin.

However, that gives rise to yet another problem. Lignin is important for plant development. Cutting down on lignin could lead to stunted growth, resulting in lower crop yields.

All of this has stymied efforts to relieve the biofuel field from its dependence on corn, soy, and other edible crops.

A more holistic approach to biofuels

Purdue scientist and director of the school’s “C3Bio” biofuel research center Maureen McCann has taken a different approach.

Having studied zinnias, poplar trees and hundreds of other plants, McCann and her team have viewed biofuels through a broad lens that includes fuel, food and other products, such as specialized chemicals.

Within that worldview, they have articulated three holistic goals: increasing the yield per acre, increasing the quality and value of each plant, and increasing the land available for growing crops profitably.

As part of a nine-year Energy Department grant, McCann has been collaborating with chemists and chemical engineers to develop a biofuel system that breaks down both cellulose and lignin with maximum efficiency.

Instead of trying to reduce lignin content, McCann’s approach involves understanding that plants are “marvelous chemists.” Understanding the chemistry is the key to developing new approaches.

For example, one avenue is to engineer plants with looser connections between their cells. Another pathway involves developing plants with catalysts built into their cell walls.

“In both cases, this work is a reflection of synthetic biology thinking. We don't simply take what nature gives us; we think of ways to improve the performance of the biomass using the entirety of the genetics toolkit,” McCann explains.

Unexpected help from “slivers of land”

McCann also participated in a newly released Purdue study that describes how farmers can deploy biofuel crops to help increase the yield of their food crops, while also protecting water resources.

The research team, headed by Purdue professor Nick Carpita, focuses on one solution for two problems.

On the one hand, large scale farmers who can afford nitrogen-based fertilizers get better biofuel crop yields, but they risk damaging nearby water resources. On the other hand, many small hold farmers can’t get better yields because they can’t afford fertilizer.

The solution involves planting perennial biofuel crops, like sweet sorghum or switchgrass, as borders around food crops. These “slivers of land” would serve as buffers to prevent fertilizer from impacting water resources.

Meanwhile, biomass harvested from the perennial border crops would be gasified in order to extract hydrogen, which is the main ingredient in ammonia.

The researchers acknowledge that fertilizer produced by such a system probably could not compete at scale in developed countries, where conventional fertilizer is less expensive. Instead, they foresee application in remote areas or emerging economies where soil quality is poor and fertilizer is unaffordable. They envision a decentralized system of small or mobile facilities that bring fertilizer production technology to the farmer.

“Farmers producing more high-value horticultural crops would see a boost in income and a multiplying effect increasing economic development in rural communities,” explains researcher Gary Burniske, who is the managing director of the Purdue Center for Global Food Security.

Who needs land for biofuel crops?

Using land for biofuel crops is just one option. Researchers are also exploring the use of ponds and constructed waterways to grow algae for biofuel. In one especially interesting development, the US Department of Energy is funding a study that deploys captured carbon to grow algae biofuel crops.

Similarly, another Energy Department initiative involves harvesting seaweed for biofuel.

All in all, the drop in oil and gas prices has created a competitive nightmare for biofuel producers today, but that is only temporary. As the urgency of climate action accelerates, next-generation research is already creating space for biofuel crops in the sustainable economy of the future.

Image credit: Diane Helentjaris/Unsplash