Senior Design: From Sugarcane Byproduct to Seltzer Beverage

Processed sugarcane.

As part of their capstone senior design project, a team of Drexel chemical engineering students are working on an innovative process to convert bagasse, a waste product from sugarcane processing, into a unique alcoholic seltzer drink. The project not only showcases the students' engineering skills but also highlights their commitment to sustainability and waste reduction.

Senior design is a culminating experience for all engineering students at Drexel, where they apply the knowledge and skills acquired throughout their academic journey to tackle real-world problems. Matthew Billemeyer, Anthony Campagna, Kevin Snow, and Francis Dolan have chosen to focus on developing a novel process that utilizes cellulose extracted from bagasse to create a marketable beverage product.

"We wanted to work on a project that not only challenged us as engineers but also had the potential to make a positive impact on the environment," said Billemeyer, one of the team members. "By using bagasse, a waste product from the sugarcane industry, we're able to create value from something that would otherwise be discarded."

The process begins with the steam explosion of bagasse, which physically separates the fibrous material into its component polymers: lignin and cellulose. The lignin is then dissolved using sodium hydroxide (NaOH) and separated from the solid cellulose in a centrifuge. To make the cellulose more fermentable, the team employs a unique decrystallization process using phosphoric acid to convert the cellulose into an amorphous form. Ethyl formate is then used to extract the phosphoric acid from the cellulose, and the two components are separated in a series of flash drums.

"One of the key challenges we faced was optimizing the decrystallization process," explained Campagna. "By converting the cellulose into an amorphous form, we're able to increase the efficiency of the fermentation process and ultimately produce more ethanol."

The fermentation process involves breeding yeast in a chemostat drum and feeding it to the fermenter along with the amorphous cellulose. The cellulose is first treated with enzymes to convert it into glucose, which is then buffered to maintain a suitable environment for the yeast during the fermentation process. Finally, the ethanol is separated from the side products and excess water. The remaining solids can be sold as fertilizer or animal feed stock, ensuring minimal waste generation.

"We've worked hard to design a process that maximizes the use of all materials and minimizes waste," said Snow. "By finding ways to repurpose the byproducts, we're able to create a more sustainable and economically viable solution."

What sets this project apart is its focus on sustainability and the utilization of a waste product from the sugarcane industry. By developing a process to convert bagasse into a value-added product, the team is not only demonstrating their engineering prowess but also their commitment to environmental stewardship.

"This project has been an incredible learning experience for all of us," said Dolan. "It's shown us how we can apply our engineering knowledge to develop solutions that benefit both industry and society as a whole."

As the senior design project progresses, the chemical engineering team will continue to refine their process and optimize each step to ensure maximum efficiency and product quality. Their work serves as an inspiring example of how Drexel engineering students are applying their education to tackle real-world challenges and create a more sustainable future.