Manufacturing sustainable aviation fuel with CO₂ byproducts of ethanol production could reduce carbon intensity by more than 80% compared to fossil fuels.

The CO₂ released from corn during ethanol production could actually be a valuable, underutilized resource for producing aviation fuel rather than a waste byproduct, according to a study published in the SAE International Journal of Sustainable Transportation, Energy, Environment, & Policy.

Unlike the CO₂ from coal plants or cement kilns, which requires a lot of energy to capture, fermentation to produce ethanol releases very pure streams containing 85% CO₂ by volume or higher. As the corn plants sequestered CO₂ from the air, capturing the CO₂ released from fermentation and using it as fuel would reuse CO₂ without adding more to the atmosphere.

“It is exciting to explore whether this ‘waste’ stream can actually become a significant asset, turning inefficiency into advantage and accelerating the real-world application of emerging technologies,” said Stephen McCord, a research scientist in mechanical engineering at U-M and lead author of the study.

With aviation producing over a gigaton of fossil CO₂ emissions annually, sustainable aviation fuel produced from non-fossil carbon stocks can help reduce these emissions. Often made from biomass waste or cooking oils, small percentages of sustainable aviation fuels are already blended with conventional kerosene fuels, with the aviation industry and travelers pushing towards larger integration.

The United States produced 15.6 billion gallons of ethanol in 2023, releasing 48 megatons of CO₂, offering a route to produce sustainable aviation fuel at scale. With several different ways to make sustainable aviation fuel from bioethanol, the research team compared pathways to determine the ones with the lowest environmental impact.

“We hope to inform future development and policy by highlighting which routes are most promising for reducing aviation’s carbon footprint using existing waste resources,” said Volker Sick, former Director of the Global CO₂ Initiative and the DTE Energy Professor of Advanced Energy Research at U-M and senior author of the study.

The current corn-based sustainable aviation fuel production method chemically modifies ethanol to make aviation fuel through a process called Alcohol-to-Jet. Although it has a high fuel yield of 90%, this route only reduces carbon intensity by about 4.5% to 20% compared to kerosene jet fuel.

The research team compared this method to two CO₂-based routes. Both methods begin by converting captured CO₂ into syngas, a mixture of carbon monoxide (CO) and hydrogen gas (H₂). The gas fermentation route uses syngas to create ethanol as an intermediate step, then uses Alcohol-to-Jet to produce fuel. The Fischer-Tropsch Synthesis route instead feeds syngas into a reactor, synthesizing the long-chain liquid hydrocarbons that make up jet fuel.

A life cycle assessment found both approaches outperformed conventional methods, with Fischer-Tropsch Synthesis projected to reduce carbon intensity by up to 90% while gas fermentation was projected to reduce it by 84%.

When considering existing bioethanol facilities and workforce skills, gas fermentation followed by Alcohol-to-Jet came out on top as the path with the smoothest transition despite a slightly lower carbon intensity reduction.

“A variety of factors need to be considered when planning how to produce large quantities of sustainable aviation fuels from CO₂. Starting with CO₂ from corn ethanol fermentation promises the fastest path to scaling up this new industry,” said Sick.

As a follow-up, the research team assessed the economic competitiveness of these two pathways to understand which would operate best in real-world conditions and which could be deployed quickest in the US.

With electrification and hydrogen both facing significant technical and practical obstacles for long-distance air travel, hydrocarbon fuels will likely remain essential for aviation in the foreseeable future.

“These conversion routes provide a viable way to ‘defossilize’ aviation fuel and make meaningful progress towards reducing aviation’s carbon footprint—offering a realistic, near-term solution where alternatives are limited,” said McCord.

OpenAI’s recent restructuring of its for-profit arm to a public benefit corporation is a smart move that will allow the organization to increase its investment opportunities and maintain its nonprofit roots, according to a Northeastern University nonprofit management expert.

“They are still keeping their nonprofit legacy intact in many ways,” says Cortney Nicolato, a Northeastern lecturer and president and chief executive of the United Way of Rhode Island, a branch of a global nonprofit that provides and funds social service programs to people in need.

OpenAI recently announced after months of negotiations between attorneys general in Delaware, where it was incorporated, and California, where it is currently based, that it had changed the organization’s structure.

As part of the reorganization, OpenAI, the well-known AI technology company, changed its for-profit business into a public benefit corporation. A public benefit corporation is a type of for-profit business that, in addition to having shareholders, has committed to pursuing societal causes.

OpenAI’s recently renamed nonprofit arm, the OpenAI Foundation, has a 26% equity stake in the company. Microsoft, which has long been one of the company’s biggest supporters, has a 27% equity stake in the company. The other 47% equity stake is owned by employees, previous employees, and current and new investors, according to an OpenAI blog post.

Nicolato says OpenAI’s pivot to a public benefit corporation makes sense as it is increasingly becoming one of the more popular business models for companies looking to make societal changes.

Similarly, Anthropic, another AI company, is a public benefit corporation.

Other companies that follow a similar structure are Bombas, which in addition to selling socks, also gives them away; Toms Shoes, which gives away a free pair of shoes for every pair sold. They are what are known as B Corporations, which, similar to public benefit corporations, have a social component to their for-profit businesses.

“There are a lot more B Corps now than there were before,” says Nicolato. “So I’m not surprised that they went this route because it offers more opportunity to license out products.”

At the same time, however, given that the nonprofit’s arm retains a large stake in the private arm, it means it is still acting as a check on the organization as a whole, she says.

In addition to the restructuring, OpenAI announced that it is investing $25 billion for the nonprofit arm to focus on two specific areas—health care and AI resilience.

“I think what they’ve done with their nonprofit arm is really hone exactly what that nonprofit will be focused on,” she says.

But why did OpenAI do this restructuring in the first place? What are the economic benefits?

Gastón de los Reyes, an international business and strategy professor at Northeastern University, says this new restructuring significantly increases OpenAI’s capital investment opportunities as it continues to spend billions on the development of its AI technologies.

“What this change allows is for a lot more investors to be able to make huge amounts of money by owning a share of OpenAI,” he says.

Specifically, this new structure positions OpenAI for a potential initial public offering and removes a previous profit cap for investors, he explains.

“The floodgates of the capital have been opened to keep this arms race going between OpenAI, Google and Anthropic,” he says, highlighting the companies’ pursuit of artificial general intelligence, a form of AI that is cognitively as capable or more capable than humans.

Notably, OpenAI was incentivized to create the new corporate structure to take full advantage of an investment from the Japanese conglomerate Softbank, de los Reyes says.

Speaking to the nonprofit’s now massive $130 billion stake in the for-profit arm, Craig Welton, also a Northeastern lecturer and the chief development officer of the Boys and Girls Clubs of Dorchester, a local branch of the national after-school organization, says the potential societal benefits are massive.

“It will probably be the most well-funded foundation in the country when it’s all said and done,” he says.

Whether the organization actually lives up to its goals will certainly depend on its nonprofit and for-profit boards in maintaining OpenAI’s stated missions and goals, he says.

This story is republished courtesy of Northeastern Global News news.northeastern.edu.

In the history of gluteal enhancement, Mexico City stands out. It protrudes. It was here, in 1979, that a plastic surgeon, Mario González-Ulloa, first installed a pair of silicone implants designed specifically for the buttocks. The textbook Body Sculpting with Silicone Implants calls González-Ulloa the “grandfather of buttock augmentation.” The early 2000s saw a new generation of Mexico City buttock transformation luminaries, notably Ramón Cuenca-Guerra. In his 2004 paper “What Makes Buttocks Beautiful?” Cuenca-Guerra laid out four characteristics that “determine attractive buttocks” as well as the five types of “defects,” with strategies for correcting each one. I, for instance, have defect type 5, the “senile buttock.” (González-Ulloa’s depiction of this took the form of charcoal nudes contrasting “the typical ‘happy buttock’”—high, rounded, dimpled—with its counterpart, the low-slung, drooping “sad buttock.”)

While I understand the value of standardizing procedures and setting guidelines for surgical practice, I tripped over Cuenca-Guerra’s methodology. How and by whom had the determinants been determined? Like this: 1,320 photographs of “nude women ages 20 to 35 years, as seen from behind” were presented to a panel of six plastic surgeons, who “pointed out which buttocks they considered attractive and harmonious, and features on which this attractiveness depended.” Oho!

I thought it would be interesting to talk to Cuenca-Guerra about the notion of a visually ideal female figure. As something that could or should be surgically created (or, in the case of the senile buttock, re-created). As something that even exists. I sent an email using the address on a more recent journal paper. There was no reply. Ramón Cuenca-Guerra’s buttocks are in worse shape than mine. He has been dead for some time. I was able to reach a colleague of his, José Luis Daza-Flores. Here was the third generation; just as Cuenca-Guerra had studied under González-Ulloa, Daza-Flores had studied under Cuenca-Guerra, extending the lineage and making Daza-Flores, I guess, “the son of buttock augmentation.”

Daza-Flores collaborated with Cuenca-Guerra on a paper called “Calf Implants,” in which the team did for the lower leg what Cuenca-Guerra had done for the butt: laid out “the anatomical characteristics that make calves look attractive” and the “defects” to be addressed. Here again, plastic surgeons were recruited to judge images—2,600 of them, a vast photographic millipede of female legs.

The paper took an unexpected turn. Referring to a marked-up photograph of a lower leg deemed attractive, the authors tried to show that its measurements conformed to what is known in mathematics as the divine proportion (or golden ratio)—1.6 (I’m rounding it off) to 1. When you divide a line into two parts such that the whole length divided by the long part is equal to the long part divided by the short part, both those ratios will be 1.6 to 1. I found an illustration of the divine proportion on a website called Math Is Fun (and convincing no one). The golden dividing line splits the length such that one chunk is roughly two-thirds and the other is around one-third. The ancient Greeks divided the “ideal” face into similarly proportioned thirds. This was the first time I’d seen the divine proportion applied to a leg.

The paper contained sentences like this: “Seventeen women had thin legs, in the shape of a tube, and a mere 1:1.618 ratio in the A-P and L-L projections.” Though I confess to not grasping the particulars of the discussion, I believe that to be a mathematically precise description of cankles.