Robust microbes – with business potential – is the mission in the Jarboe Research Group

Laura Jarboe
Laura Jarboe, associate professor and chair of interdepartmental microbiology graduate program

To the average outsider looking in at scientific research it’s easy to think that “science is science.” But in reality, especially in today’s world, scientific researchers need a partnership with something else – a good head for business.

“At the university level, it’s one thing to do great science, but to help people, you have to engineer the economics.” Those words come from CBE associate professor Laura Jarboe, whose work, at its core, deals with making microbes more robust – so they can create better, more desirable, more durable products, that, yes, have a better potential for helping people and of being sold to end users. “There are a lot of good ideas out there,” Jarboe says, “but what counts is economic viability.”

Jarboe can point to a great deal of history where chemical engineering has made this difference through engineering of microbes and organisms, and how this impacts her own research.

Insulin: Jarboe points to the development of consumer-friendly insulin as a prime example of modifying organisms to achieve an end. When insulin was introduced as a medical product in the early 1900s its therapeutic value was readily apparent. But being extracted from animal pancreases, it was hard to harvest, was expensive, and caused an allergic reaction in some patients. The genetic modification of the bacteria E. coli to produce insulin, via the introduction and expression of a non-native gene, enabled the production of safe and affordable insulin at scale. It was a landmark development, as it was the first time that bacteria had been explicitly modified to enable production of a non-native compound.

Penicillin: The world’s first true antibiotic, credited as one of the most important developments in the history of medicine, was initially prohibitively expensive and could not be used at anything other than the proof-of-concept level. “It couldn’t help anyone if no one could afford it,” says Jarboe. It was the development of improved fermentation methods and identification of more robust production organisms that helped spur large-scale commercial production by the mid-1940s.

Petroleum: The champion of providing power and heat, Jarboe is quick to state that many people are unaware of the role petroleum also plays in production of commodity goods. And after decades of the growth of fossil fuels in the petroleum industry, she points out there is now a move toward biomass-based energy that can supplant or replace petroleum; but again, the mantra of needing to be economically feasible rears its head. “Engineers are trying to develop and improve processes that use microbes to produce compounds we currently get from petroleum, while being economically competitive with these petroleum-based processes.”

It’s the mission of developing microbial organisms that are more robust in industrially-relevant conditions that is the primary focus of Jarboe’s research group. In short, cells that can be used in large numbers and can stand the rigors of industrial-scale production. A substantial concern here is the fact that many of these biorenewable products are toxic to the production organism, just as ethanol is toxic to humans at high concentrations. This toxicity plays a key role in the economic viability of the development of some products, as a low product concentration increases the cost of product recovery.

In many cases, this toxicity is due to damage to the microbial cell membrane by these fuels and chemicals. The membrane of a cell acts as a protective barrier between what’s outside the cell and what’s inside it. “Lots of materials can damage the membranes of cells,” Jarboe explains. “Cell membranes are very important and must be durable,” she says, and uses human skin as a metaphor for this. “It’s like a proper cell membrane – good in, bad out.”

“There are several important metrics here to indicate that the membrane is functioning correctly. Membranes must remain intact – they cannot have holes. They have to have integrity – they can’t be leaky. And they need to have proper fluidity.” (She uses an example of butter vs. olive oil in the kitchen. Butter melts quickly under heat, where olive oil stays fluid.) Jarboe and her group are countering membrane damage by changing the composition of the cell membrane.

“We want to change the composition of the membrane to counter balance these effects and make the membrane more functional – so things can be made in higher concentrations and be more economically viable. We’re changing the genetics of the organism to make a more functional membrane. We’ve seen that this approach can improve production of a variety of attractive products, including styrene.”

Jarboe is the former chair of Iowa State’s Interdepartmental Microbiology Graduate Program and in 2018 was selected as a College of Engineering representative of the Iowa State Biotechnology Council.