E. coli rewired to control growth as experts let them make proteins for medicine

Experts have equipped biotech workhorse bacteria with feedback control mechanism to balance growth with making protein products. 

Medicines like insulin and interferon are manufactured using genetically engineered bacteria, such as E. coli. E. coli grow quickly and can be given DNA that instructs them to make proteins used in medicines and other materials.

However, the extra burden of producing new proteins hampers bacterial growth, which slows production. Solving this problem is an area of great interest for biotechnology and synthetic biology.

In a paper featured on the front cover of Nature Methods, Imperial College London experts have created a feedback system that lets engineered E. coli solve their own problem. This is accompanied by a second paper from the same team published in Nature Communications reporting on a new method to predict how E. coli's growth is affected by burden.

To create the feedback system, the researchers first used RNA sequencing - a technique that measures the expression of all genes in a cell - to observe which genes inside the bacteria naturally change behaviour when the cell is burdened.

After identifying the bacterial DNA responsible for burden-led behavioural change, the team created a feedback loop by linking this DNA to the DNA for protein production.

"Once cells detect too high a burden, they trigger a feedback controller that reduces protein production to a level that allows the cell to grow well."