Reactions: Cellulose to ethanol and ethics in chemistry

Letters to the editor

Cellulose to ethanol

I would like to comment on your guest editorial in the Feb. 13, 2023, issue by Michael McCoy re chemical comeback stories we like (page 2). In the editorial, he says one of his first stories for C&EN, back in 1998, was about cellulose to ethanol. He says cellulosic ethanol got its second wind in the 2010s. I would like to correct the record.

Gulf Oil Chemicals had a project for the conversion of cellulose to chemicals in 1975 under the direction of George Emert. Before that it was funding research at Virginia Tech under Ross Brown to identify enzymes that broke down cellulose. There was also active research at the Natick Army Research Center; the University of California, Berkeley; and the Massachusetts Institute of Technology, to name a few. However, Gulf was the only commercial operation that was working on the whole process from the production of enzymes to the production and purification of the end product.

From 1975 to 1979, Gulf received 17 patents on the process it developed (the Gulf process) and had numerous publications. Brown’s lab and his graduate students presented a number of papers on the identification and purification of cellulases. The Gulf research included the identification of substrates that were available in sufficient quantities to make commercial production feasible as well as the best methods of pretreatment to make the cellulose available to the enzymes. Gulf worked with Natick on the organisms to produce the cellulases and with Nippon Mining in Japan on the organisms for the end product.

Initially, the end product could be citric acid or ethanol or one of many other chemicals. However, the oil embargo at that time made it obvious to go after ethanol. Gulf built a pilot plant capable of 0.9 metric tons (t) to confirm the process could be scaled and then began to design a 45 t per day demonstration plant to convert air-classified municipal solid waste to ethanol in partnership with Raphael Katzen Associates in Cincinnati. In 1979, Gulf donated the cellulose-to-ethanol project to the University of Arkansas, where the research continued for a number of years. At that time, major funding came from the US Department of Defense and the Solar Energy Research Institute.

So you see, by 1998 the conversion of cellulose to chemicals was well understood and commercially feasible.

I hope this helps show that 1998 was actually the comeback story.

Paul Blotkamp
Lincoln, Nebraska

Ethics in chemistry

As a 52-year member of the American Chemical Society, I want to say that C&EN is an exceptional magazine that I look forward to receiving every week. I want to express my thanks to those responsible for its publication over the years.

It was the recent article on Shyamala Rajender, in the March 13, 2023, issue of C&EN (page 18), that finally motivated this correspondence. I believe it is also fortuitous that this article was about a University of Wyoming Chemistry Department graduate, as am I.

I wanted to share my concern as a chemist regarding the professional ethics of chemists. This concern has been prompted by the many articles appearing in C&EN in the past on commercial, synthetic chemicals that cause environmental and health concerns. These chemicals include pesticides, fungicides, and various per- and polyfluoroalkyl substances (PFAS) that are toxic to living things and are cumulative and long lived in the environment. Most of these chemicals have not had adequate study to know what their holistic impact might be and for how long.

It is my thought that most of these chemicals began by some chemist synthesizing them and over time made their way to be commercialized for various uses. I find it hard to believe that many of these chemicals were not known or at least suspected of being detrimental and even toxic to the environment by those commercializing them. Nevertheless, commercialization proceeded, and now these chemicals are widely spread over Mother Earth. As much as I believe all things are interconnected and interdependent, the negative impact of these chemicals in the environment has broad-ranging, long-term consequences.

As chemists, are we not at least partially responsible for these negative consequences? My thought is that we are and that even more toxic than some of the chemicals we have produced and released to the environment is money. The distracting light given off by money has stolen some of our professionalism. I suggest that one possible solution is that professional ethics be included in the required chemistry curriculum for graduation.

Let’s take heart as Rajender did, finding the courage and fortitude against seemingly insurmountable opposition to show up, stand up, and speak up.

John L. Cox
Richland, Washington