The durability of plastics has fueled their widespread use but also underlies their environmental impact. Since most are petroleum derived, they are non renewable and vulnerable to geopolitical pressures. Research worldwide is pursuing biodegradable and bio based alternatives, but challenges with yield, purity, and cost remain.

Kobe University bioengineer Tanaka Tsutomu explains:
Most biomass based strategies target molecules made of carbon, oxygen, and hydrogen. Yet promising high performance plastics also involve elements like nitrogen and there are no efficient biological production routes. Purely chemical methods, on the other hand, inevitably create unwanted byproducts.

One such nitrogen containing candidate is pyridinedicarboxylic acid . It is biodegradable, and PDCA based materials match or surpass the physical properties of PET, a staple in packaging and textiles. Our group’s goal, says Tanaka, was to exploit cellular metabolism to assimilate nitrogen and build PDCA entirely within microbes.

In Metabolic Engineering, the team reports achieving PDCA production in bioreactors at over seven times higher concentrations than previously recorded. Crucially, they showed that metabolic reactions can incorporate nitrogen cleanly and without byproducts, making synthesis both efficient and sustainable.

The researchers faced hurdles along the way. A key challenge arose when an engineered enzyme produced hydrogen peroxide, which then attacked and deactivated itself. By fine tuning culture conditions including adding an hydrogen peroxide scavenger they overcame the bottleneck, though the extra step may complicate large scale production.

Looking ahead, the team is already planning improvements.Each obstacle points us toward solutions,Tanaka says.Now that we can achieve sufficient quantities in bioreactors, we can move closer to practical applications. More broadly, our success in harnessing nitrogen metabolism expands the range of molecules accessible through microbial synthesis, further boosting the potential of bio manufacturing.

Source:https://www.kobe-u.ac.jp/en/news/article/20250904-67078/