In 2018, Frances H. Arnold, Chemical Engineering professor at the California Institute of Technology (Caltech), was awarded the greatest prize of her career: the Nobel Prize in Chemistry. The honor was granted to the US scientist for developing the directed evolution technique, which manipulates the genetic composition of microbes so that their biochemical functions can perform specific tasks sustainably.

The directed evolution method produces specific enzymes and biomolecules that can perform actions in a much cleaner and more efficient fashion than standard chemical processes, which usually rely on solvents and metals. Among the usages already developed are the detoxification of chemical spills, the removal of fabric stains in an eco-friendly manner and even the creation of medicine free of eco-hostile metallic catalysts.

“I get these students who come in and say, I want to help people. I say, people get plenty of help.  Why don’t you help the planet?”, asked Arnold in an interview with The New York Times. “All my projects are about sustainability, bioremediation, making things in a cleaner fashion,” the environmental chemist reiterated. 

From the advances she establishes in academic labs, Arnold has founded many environmental-oriented companies. One of them is Provivi, which is devising techniques for synthesizing insect mating pheromones cleanly, cheaply and on an industrial scale, with the goal of combating agricultural pests in an eco-friendly way.

The chemical engineer’s most recent venture is Aralez Bio, which will apply the principles of directed evolution to produce customized amino acids for drug companies. “They [drug companies] produce 100 times more waste than product,” said Christina Boville, chief scientific officer of the new venture, to NYT. “We think we can do much better. Our technology actually works,” said Arnold’s project partner.

How directed evolution technique works

The method developed by Francis Arnold inverts how most chemists work. It means that, instead of calculating and engineering new proteins inside microorganisms actively – a procedure which demands high investment in time with a low success rate -, the 2018 Nobel laureate’s approach is to direct basic evolution mechanisms to devise and update protein compositions.

It works like this: The scientist picks a protein with a potentially useful asset, such as stability under high temperatures. Then, in the lab, she randomly edits the gene that encodes the protein. From then on, she observes whether there is improvement in the resulting protein. 

By repeating this procedure very often, as many times as necessary to achieve any interesting biochemical function, microbes are encouraged to face adaptation and survival challenges. With this mechanism, some microorganisms engineered in Arnold’s lab could even do something “natural” microbes never accomplished: produce bonds between carbon and silicon – a breakthrough for the scientific community. 

“In the lab, we’re discovering that nature can do chemistry we never dreamed was possible,” Dr. Arnold said. “We’re adding whole swathes of the periodic table to the chemistry of the biological world,” she completed.

Content published in July 17, 2019