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Aline M. Castro pulls out a pair of yellow cardboard glasses that she made. They look like the frames people wear on New Year’s Eve, where numbers adorn a person’s face—except these don’t flaunt digits. Small red, white, and black pompons form a chemical structure.
Vitals
Hometown: Rio de Janeiro
Education: BS, chemical engineering, 2004, MSc, chemical and biochemical process technologies, 2006, and DSc, chemical engineering, 2010, Federal University of Rio de Janeiro
Current position: Consultant, Leopoldo Américo Miguez de Mello Research, Development and Innovation Center, Petrobras
Projects: In 2022, I founded a publishing house named Ciência, Leitura e Afeto, which is dedicated to publishing science communication books, all dedicated to children’s education.
Hobbies: Sewing, painting, and repurposing waste materials, like using waste bottles as gardening pots. I love storytelling for children, and I customize my lab coats to be very colorful and fun for them
I am: Latina
“This is the sucrose molecule,” the chemical engineer says from the other side of a computer screen, on a video call. She points to each of the two lenses: “There is glucose and fructose.”
Castro spent her early career researching how to use sucrose, specifically cane sugar, to replace dirtier energy sources like fossil fuels. Brazil, where she lives and works, is the world’s largest producer of sugar and unsurprisingly is the second-largest producer of ethanol, a fuel that can be derived from the sweet molecule.
She likes to wear these glasses when she talks about sustainability to elementary-age students. She makes such materials with her daughter on weekends. Some weeks, they craft a quick pair of glasses or customize an ocean blue tiara featuring an octopus and clown fish. Other projects take several weekends—like the lab coats the mom and daughter paint with scientific illustrations of green plant cells or red blood cells.
Castro is a researcher who is also an educator, writer, and mother. She’s authored seven picture books about environmental science to help communicate the topic to young children—a passion inspired by her daughter. But her day job is with Petrobras, a Brazilian oil company. Since 2007, she’s pioneered innovations in renewable fuels, plastics recycling, and carbon capture technologies as a senior researcher and consultant with the state-owned company.
But she didn’t join the company to perpetuate the use of fossil fuels during the age of record-breaking heat waves and wildfires. “To work with petroleum was never my intention,” she says. She believes energy companies like Petrobras can help fix the mess they’ve made through their investments in renewable energies and alternative feedstocks such as biogas.
Much of her time currently goes toward developing new approaches in carbon capture and utilization. Some scientists find carbon capture technology controversial, in part because of its popularity among fossil fuel companies, while others deem it necessary for lowering global greenhouse gas emissions. Castro is investigating basic solvents that can separate carbon dioxide from methane or flue gas and transform it efficiently into new products such as carbonates and carbamates.
For example, carbonic anhydrase enzymes help accelerate the reaction between CO2 and water to create bicarbonate, a versatile chemical commodity, out of the greenhouse gas. If Castro can identify which particular process conditions are best, carbon capture facilities may require smaller reactors, less steel, less water, and overall less energy in the future.
We need to speed up the implementation of this low-carbon technology on a very large scale.
There are “a lot of advantages,” Castro says. “We need to speed up the implementation of this low-carbon technology on a very large scale.”
The enzymes that capture CO2 in an industrial setting are the same ones that move CO2 through our bodies, Castro says. “It was always fascinating to see this parallel between the biology of real life and chemistry and how we can mimic these natural reactions,” she says.
It was this fascination and love for the natural world that drew her to science in the first place. “I was aware of environmental concerns of the planet, so I wanted to do something that could contribute to the planet being a better place to live,” she says.
Castro grew up near the favelas of Rio de Janeiro, dense neighborhoods where many households have incomes below Brazil’s poverty line and lack basic sanitation services. “The urban landscape was degraded,” she says. When she’d walk the streets with her mom, she would see plastic waste and tires scattered about. She and her mom would escape on the weekends to parks and botanical gardens when her mother was free, but Castro would be alone most days while her mom was working. It wasn’t until her 10th birthday that she found a respite from her loneliness—in science.
Her dad gifted her a microscope that she could use to discover details invisible to the naked eye. She would capture ants and explore them at different zoom levels. She’d assess plant samples and dust. Sometimes, she’d mix colors and pigments just to see what would happen.
Credit: María Magdalena Arréllaga
Aline M. Castro aims to convert the carbon dioxide in postcombustion gases to carbonates more efficiently.
Today she realizes how important this free-form exploration was for her creativity, she says. In her childhood, Castro didn’t have access to new toys, so she got into crafting, creating wardrobes for her dolls out of shoeboxes. What looked like child’s play was actually helping her build the imagination she regularly flexes in the lab. “I had to train my brain to build things and to imagine how they were going to be by gluing them in this position and that and mixing materials. As scientists, we are inventors.”
Her mother helped Castro become the first in her family to go to university. Castro attended the Federal University of Rio de Janeiro (UFRJ) from her undergraduate through her doctoral studies, where she excelled.
Denise Maria Guimarãres Freire, a professor at UFRJ, describes her then student as “dedicated, attentive, and with a unique scientific curiosity.” Castro possesses the rare combination of scientific rigor, writing ability, and creativity, she says.
Nei Pereira Jr., a professor emeritus at UFRJ who also taught Castro, says she is one of the top students he ever had among the nearly 150 he supervised over his career. The pair worked together for Castro’s master’s dissertation to design “an enzymatic cocktail,” as he put it, that would help break down the cell walls of sugar cane waste in an industrial setting. These early pursuits have helped inform much of her work communicating with children—and helped inspire those adorable sucrose glasses. Pereira admires his former student’s commitment to reaching young people.
“Aline recognized the importance of bringing knowledge to this foundational level of education and has been doing so in an accessible and engaging way,” he says. “Her example should inspire other researchers to awaken children’s interest in complex subjects.”
Castro has loved writing since she was a child, but she didn’t plan to become an author. When her daughter turned 4, she started reading books to her but couldn’t find many that talked about sustainability. So she figured she would write one. Her first book was published in 2021. She donated every single copy to nonprofits working with children from lower socioeconomic groups in Brazil.
Through her books, Castro shares fantastical tales where children can travel the ocean in a submarine to clear it of plastic. She dares her readers to dream as she did when she was their age. She shows them the ways science can change the world. After all, that’s why she became a scientist in the first place.
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