The bacterium Bacillus subtilis can be found anywhere from soil to a human’s gastrointestinal tract. Known as hay or grass bacillus, B. subtilis is often used as an agricultural plant to deter pests. For humans, though, hay bacillus is usually, but not always, harmless.
Recently, Gholamreza Ahmadian, PhD, professor of industrial and environmental biotechnology at the National Institute of Genetic Engineering and Biotechnology (NIGEB) in Tehran, Iran, and his graduate student Howra Bahrulolum, explored a range of uses of B. subtilis, including the production of vaccines.
Surface display technology is the key to turning hay bacillus into a biopharmaceutical. With this process, the bacteria can be engineered to express a specific protein that appears on the surface of the cells. In vaccine applications, for example, the bacteria would carry a protein that attacks a specific virus.
Basis for producing a vaccine
According to Ahmadian and Bahrulolum, “Engineered B. subtilis spores and cells can be tailored to display proteins, making them ideal for applications such as … bioactive compound delivery vaccines.”
These scientists also point out various benefits of considering hay bacillus as the basis of producing a vaccine. For one thing, the spores of B. subtilis are stable across a wide temperature range, which reduces the cost of storage and transportation because the spores can be held at room temperature. Plus, the bacterium is already used as a probiotic, which should simplify some steps in using it as a biopharmaceutical.
As Ahmadian and Bahrulolum add: “Compared to conventional platforms like viral vectors, B. subtilis avoids challenges such as risks of pathogenicity, pre-existing immunity, and potential tumorigenesis.” The scientists also note that producing the bacterium is a “more cost-effective and scalable alternative for therapeutic protein production” than using “traditional mammalian cell culture methods.”
So, the microbe can be economically made at scale, but it’s not ready for prime-time biopharmaceutical production. For example, even though a bioprocessor can make lots of t B. subtilis, many of the cells will only express the desired surface protein at low levels. Ahmadian and Bahrulolum simply note that this challenge for hay bacillus “limits its suitability for industrial applications.” For now, that’s more than a limitation. It’s a dealbreaker until that problem can be solved.
Still, Ahmadian and Bahrulolum believe that hay bacillus has “the potential to transform bioprocessing and biomanufacturing, driving innovation in global healthcare.” If that turns out to be the case, terrific! Nonetheless, lots of work remains before this pesticide becomes a biopharmaceutical.