A tribute to Dr. Lars G. Ljungdahl (1926 - 2023)

I was recently in Hawaii at a conference focused on sustainability.? We were discussing how science is being leveraged to make the world a better place.? For me, one person has really stood out as pivotal in this search, Lars Ljungdahl.? Unfortunately, for the world and science, Lars passed away on July 13, 2023.

Lars was from Sweden and anyone that had ever met him could not come away without hearing his accent.? As a young student from suburban Atlanta, working for a scientist from a foreign land was my first foray into the cosmopolitan world of science and the wide array of people that make the discoveries that move our collective knowledge forward. Lars was already quite famous and a busy man lecturing and participating in numerous committees and organizations including being Editor of Applied and Environmental Biology and heading up the Georgia Research Alliance which has done so much to bring eminent scholars to Universities across the state of Georgia.? Due to his schedule, my first interactions were with his team of scientists from places I had never been including China, Brazil, India, Korea, Germany, Holland, Japan and the UK.? These foreigners became my friends and eventually I became their colleague having won their respect through my ability to tinker and solve problems Lars had set for the lab.

These problems were focused on the biological systems that Lars became interested in as a young man in Sweden.? As noted in an article Lars wrote for Methods in Enzymology, he had a non-traditional career as described in his introductory chapter in the 2009 Annual Review of Microbiology.? He originally got into the field of Chemistry through the suggestion of a cousin; Lars came from a large, close knit family.? His parents, though not college graduates, encouraged him to do anything he put his mind to except, as he put it “things I would be ashamed to tell them about.”? This served him well and I would venture to say his parents would be extremely proud of their son.

Having been born in 1926, he grew up in the shadow of World War II entering secondary school in September 1939 (on the day Germany attacked Poland) and graduating in 1943 from Stockholm Stads Tekniska Mellanskola which is equivalent to a technical college in the US.? He then worked as a technician at the Karolinska Institute, where years later, his son Per would become a professor.? He also continued his studies at night at Stockholm Technical Institute where, as Lars wrote in 1945, he was taking an exam, it was learned Germany had surrendered to the allied forces and his instructors essentially let him finish early and “join the fun outside.”? So, it seems, war and peace had a major impact on his life, possibly resulting in his desire to use science to make the world a better place.??

Working at the Karolinska Institute brought him in contact with many scientists interested in subjects related to medicine.? One of these, Pehr Edman, was focused on sequencing proteins including angiotensin which he worked with Lars on.? As many readers may be aware, Pehr Edman went on to develop what is now known as Edman degradation and is used to determine the N-terminal sequence of proteins.? Lars would go on to be another celebrated biochemist, but first a trip to the Stockholm Brewery was in his plan.

Lars started working at the Stockholm Brewery when he was 21 (probably drinking well before that!)? and worked there for 11 years as a research chemist.? Lars told me a story that when he worked there, he noted that the brewing tanks were not very clean so he decided to thoroughly clean the tanks.? This resulted in a change in the flavor of the beer that the locals didn’t appreciate!? This is where he was first introduced to the field of anaerobic metabolism and polysaccharide degradation.? He studied the components of barley and the resulting wort and also considered the use of anaerobic bacteria for the degradation of cellulose.? He would go on to discover much that is known both about anaerobic metabolism as well as the breakdown of cellulose as 2 key areas of research for the rest of his career.??

His introduction to Harland Wood came through the cousin that got him interested in science in the first place, Rune Stjernholm.? Harland was a professor at Case Western Reserve University in the US and was the person who’s lab had discovered CO2 fixation in the heterotrophic microorganisms.? Rune who worked with isotopes in Sweden was recruited by Harland to work in his lab that utilized isotopes for studying CO2 fixation in bacteria.? Lars indicated to Rune he would like to do as Rune did eg come to America to get a PhD which Rune helped facilitate; so in 1958 at the age of 32, old by current standards, Lars arrived in Cleveland, Ohio to start his work in Dr. Wood’s laboratory.? He would become great friends with Harland working with him until Harland’s passing in 1991.? Together they are the namesakes of the Wood-Ljungdahl pathway

Lars graduated from CWRU in 1964 and was offered a non-tenure track position. Being interested in a tenure track job, he was introduced by another CWRU professor to Harry Peck who was head of the department of Biochemistry and Molecular Biology at the University of Georgia while a conference in New York City.? Meeting up in a bar off Broadway, Harry talked Lars into coming down to Athens, GA to interview for a position at UGA which was in the midst of a science renaissance.? From 1965-1967 UGA received federal funding to develop excellence in biological sciences.? Part of the growth at UGA included hiring more than 1,100 faculty and completing the Boyd Graduate Studies building and the fermentation plant where Lars would work and teach at UGA.? The fermentation plant was eventually renamed, by former Ljungdahl Lab post-doc Tim Davies and director the Bioexpression and Fermentation Facility or BFF which I would eventually lead from 2011-2023.

Lars accepted a position in the department at UGA and starting in 1967 Lars led a team of scientists focused on what would eventually be called the Wood-Ljungdahl pathway for the synthesis of acetate from CO2.? Carbon monoxide from synthesis gas can also be utilized and this process is now being leveraged for the production of ethanol and jet fuel by Lanzatech.? Many researchers came out of Lars lab over the years that studied this process.? Later Lars picked up his earlier interest in degradation of cellulose by anaerobic bacteria which is when I joined his group.

My work with Lars started in 1992 when, as an undergraduate student in Biochemistry, I had to find a lab to satisfy the research component of my bachelor’s degree.? A friend of mine worked in Lars’ lab and encouraged me to talk to him about working in his lab.? I entered a dark office with this distinguished gentleman sitting ominously across from me.? After noting that my grades weren’t that great, he decided to take a chance on me and offered me a position in his lab. This would be the first of many opportunities that Lars made possible for me.? I graduated about a year later and Lars then accepted me into his lab as a graduated student as a second opportunity.? Other opportunities? included allowing me to intern at a biotechnology company in San Francisco, funding my travel to a conference in Nottingham, England (my first international trip) and funding travel to Japan to present some exciting research I had completed on esterases and bifunctional enzymes (my second international trip).? After graduating with my PhD in 1999, Lars and I stayed in touch meeting up on occasions including the night of the 2000 election, another pivotal event in Lars’ lifetime, for a consulting project with the Biotech company I was working with, Diversa.? And, as usual, I can thank Lars in part for getting this first job in biotech as my future manager was familiar with my work in Lars’ lab.? When I moved back to Athens in 2011, Dan Dervartainian, another professor and Ljungdahl lab neighbor when I was in grad school as well as Jan Westpheling, who served on my PhD committee member, both good friends of Lars, helped keep me updated on how he was doing.

Lars continued to work in the field until his retirement at 80 in 2006.? We celebrated Lars with a symposium that year which was preceded a decade earlier by another symposium, the art of anaerobes, celebrating his 70th birthday.? I was lucky to attend both and see many of the people impacted by his research.? These events honoring Lars’ career continue through to this year where Jay Keasling presented at the Annual Ljungdahl lecture which was funded by Lars' late wife and accomplished pianist Despy Karlas Ljungdahl.? Lars first wife, Britten whom he married in 1949 and passed away in 1995.? Weeks before his death, Lars was able to attend Jay’s lecture via zoom and was quite pleased as noted by his son Per.? These lectures and their nod to the career of Lars will persist teaching future students the utility of synthetic biology.? In fact, the microorganism Clostridium ljungdahlii has been shown to utilize the Wood Ljungdahl pathway and will lead to a more sustainable earth with the help of future scientists.