Engineered Yeast Boosts D-Lactic Acid Production for Biodegradable Plastics

Osaka Metropolitan University researchers have discovered a genetic "recipe" to transform yeast into a methanol-converting factory for D-lactic acid, a key compound in biodegradable plastics and pharmaceuticals. The study, published in *Biotechnology for Biofuels and Bioproducts*, aims to reduce reliance on petroleum-based processes. Lactic acid exists in L and D forms, with D-lactic acid being less available and more expensive. Ryosuke Yamada, lead author, noted that most lactic acid bacteria produce only L-lactic acid, while chemical synthesis yields a mixture. The team used *Komagataella phaffii*, a methanol-utilizing yeast, to optimize D-lactate dehydrogenase (D-LDH) genes and promoters for maximum D-lactic acid production. D-LDH converts precursor molecules into D-lactic acid, and promoters regulate gene expression. After testing, the researchers identified an ideal gene-promoter combination, boosting D-lactic acid production by 1.5 times compared to other methanol-based methods. Yamada stated their engineered yeast achieved the highest reported yield using methanol as the sole carbon source. This showcases the potential of tailored yeast strains for commercial compound production, offering a sustainable alternative to petroleum-based chemical production.