Production of L-lactic acid from methanol by engineered yeast Pichia pastoris.

Lactic acid (LA) serves as a widely used platform compound and has received significant attention as a raw material for synthesis of biodegradable polylactic acid. Currently, LA is mainly produced through microbial fermentation, but its high costs undermine its competitive advantage against other materials, necessitating the development of novel production routes. Methanol bioconversion represents an emerging low-carbon circular economy, where LA could become an outstanding representative product. This study successfully established an efficient methanol-based LA synthesis route in Pichia pastoris. Through systematic metabolic engineering strategies, including screening lactate dehydrogenase, modification of cofactor preference, blocking LA consumption pathway, and mitochondrial LA synthesis compartmentalization, 4.2 g/L L-LA was produced in fed-batch fermentation by using methanol as the sole carbon source. Through multi-dimensional and spatial engineering of enzyme, a cell factory was developed for efficient synthesis of L-LA, highlights the significant potential of the low-carbon synthesis route for L-LA via methanol bioconversion.