Minting next-gen industrial plastics with engineered bacteria

In the film “The Graduate,” Benjamin Braddock (played by Dustin Hoffman) has just graduated college. His prosperous parents and elders are anxious to see him do well in life, so they pepper him with career suggestions. In a swimming pool, Mr. McGuire tells Ben: “One word: plastics.”

These days, plastics are in bad odor, primarily because of their environmental persistence. Microplastics are everywhere and continue to accumulate. A biodegradable alternative that has the versatility of plastics would be welcome, and various companies are working on a variety of substitutes.

To address the biodegradability problem, and to find less polluting manufacturing methods, a South Korean group coaxed E. coli, the workhorse lab bacterium, into synthesizing polyester amides (PEAS) by engineering them to carry enzymes from other organisms and modifying growth conditions.

Unlike standard polyesters, polyester amides, which combine ester and amide linkages, are generally considered biodegradable, especially those containing α-amino acids, due to the presence of hydrolysable ester groups and the potential for enzymatic degradation. PEAs can be used in various industrial applications and in biomedical applications, including drug delivery systems and tissue engineering.

The South Korean team solved a number of problems along the way and arrived at a credible starting point for the development and scale-up:

“It is . . . notable that the physical, thermal and mechanical properties of poly (3HB-ran-1.74% 3AP) . . . are comparable to the typical property ranges of high-density polyethylene. These results indicate that poly (3HB-ran-3AP) can be considered a renewable alternative to high-density polyethylene, one of the most widely used plastics.”

Read the link for details.

Bioengineering biodegradable plastics