Jean-Philippe Tessonnier
Jean-Philippe Tessonnier

Lignin is the key material that confers rigidity to the walls of cells and tissues of most plants. It is the largest untapped renewable source of raw materials and is made of many of the same chemical building blocks as those found in petroleum-based materials; and has great potential as a raw material as an alternative to petroleum in the production of many essential compounds we use in our daily lives.

Effective conversion of lignin involves finding ways to increase the production of bio-oil and reduce a solid by-product called “char.” Recent studies suggest that pretreatment is necessary to improve product yields and lower char formation. However, there is limited understanding of the effects of various pretreatment parameters on lignin conversion.

Now, research by a team of Department of Chemical and Biological Engineering scientists, led by associate professor and Richard C. Seagrave Professor Jean-Phillippe Tessonnier, is bridging this gap by characterizing chemical transformations occurring during lignin pretreatments, and the catalytic parameters that govern the formation of chemical building blocks from the pretreated product. “An effective strategy to produce highly amenable cellulose and enhance lignin upgrading to aromatic and olefinic hydrocarbons” has been published in the Royal Society of Chemistry journal Energy & Environmental Science.

Co-authors of the research include Daniel Vincent Sahayaraj and Hamed Bateni (former Tessonnier doctoral students), A Lusi and Harish Radhakrishnan (former and current Mechanical Engineering doctoral students, respectively), Alireza Saraeian and Andew J. Kohler (former and current Chemical Engineering doctoral students, respectively); Brent H. Shanks (Anson Marston Distinguished Professor in Engineering, Mike and Jean Steffenson Chair and director of the Center for Biorenewable Chemicals); and Xianglan Bai (associate professor, Department of Mechanical Engineering).

Corn stover (dried and cut corn stalks) in field
Corn stover, as shown here in a farm field, is one type of lignocellulosic biomass that figures heavily into the process outlined in the research.

The researchers found that compared to lignin converted using conventional methods, their technique increased production of the desired compounds by up to 174%, in a substantially cost-effective manner. Furthermore, the residual pulp obtained using this method was enriched in sugars and was thus more amenable for conversion to fuels and chemicals than the parent biomass.

The breakthrough comes from the discovery that supercritical ethanol combined with a metal catalyst effectively lower char formation and enhance the volatilization of lignin-derived carbon.  The strategy was then extended directly to lignocellulosic biomass (corn stover, switchgrass, red oak) to fractionate and pretreat lignin in a one-pot approach. The lignin oil obtained from this process exhibited an excellent potential to be converted into platform chemicals.

Overall, this work is seen as paving the way for production of greener chemicals and biofuels through efficient lignin conversion, for a better future.

Graphic depicting overall process of the research
This illustration from the group’s published paper provides an overview of the process used to achieve the results.


1 2 3 5
June 11th, 2024

Sullivan Flynn: The right people in his corner 

Sophomore Sullivan Flynn came to Iowa State excited to experience something bigger than himself while also having a group of […]

June 11th, 2024

Mary Thatcher: Prepared for what’s next 

For many students, it can be challenging to determine what path to take. Iowa State’s Chemical and Biological Systems Engineering […]

May 31st, 2024

“No other course is like this:” New class allows chemical engineering students to explore product development

One of the student teams in the initial semester of CH E 4290 poses with the portable oven they developed […]

May 1st, 2024

Victoria Kyveryga: Outstanding senior in chemical engineering

Hometown Ames, Iowa Clubs and activities Ukrainian Club, Engineering Student Council, the Undergraduate Research Ambassadors group, and Central Iowa Symphony.  […]

March 11th, 2024

Wenzhen Li, Jean-Philippe Tessonnier become Royal Society of Chemistry Fellows

Wenzhen Li (left) and Jean-Philippe Tessonnier have become part of an elite group of scientific advocates in the Royal Society […]

March 1st, 2024

“Spirit of innovation” helps lift Jean-Philippe Tessonnier to National Academy of Inventors

Jean-Philippe Tessonnier, Richard C. Seagrave Professor in Chemical and Biological Engineering, has been named a Senior Member of the National […]

February 26th, 2024

Could the future of powering Iowa homes and farms be microbes?

Cyclone Engineer Ratul Chowdhury is advancing biobatteries that use microbes to turn trees and plants into electricity. Chowdhury, an assistant […]

February 13th, 2024

A better way to (re)harvest rare-earth metals

Rare-earth metals are an indispensable part of today’s high-tech consumer products. As demand for them increases, so does the need […]

December 12th, 2023

Mya O’Connell: Outstanding senior in chemical engineering

Hometown  Manly, Iowa  Clubs and activities  I work as a Resident Assistant and as a Peer Mentor. In the past, […]

November 16th, 2023

AIChE student chapter again records successes at annual meeting – including another Outstanding Student Chapter honor

The Outstanding Student Chapter award is presented at the meeting. Shown is AIChE student chapter representative Hailey Bates (center), ISU […]