Lactate biosynthesis from methanol using metabolically engineered Pichia pastoris

洪嘉彥Billy C. Hung*, Ethan I. Lan

Institute of Molecular Medicine and Bioengineering, Department of Biological Science and Technology

National Yang Ming Chiao Tung University, Hsinchu City, Taiwan

*E-mail: billy3565@gmail.com

Global warming has emerged as a serious issue in recent years due to the rise in concentration of carbon dioxide (CO2). Currently, carbon capture and utilization industry can convert CO2 into formic acid and methanol. However, the current application and value of these one-carbon compounds are limited, which hinders the overall carbon capture and utilization process. Therefore, converting these one-carbon compounds into value-added products are of increasing importance.

Lactate is a valuable C3 acid widely applicated in cosmetic and chemical industry, also used as a precursor for biodegradable polymer, PLA. In this study, we aimed to engineer a methylotrophic yeast, Pichia pastoris, to produce lactate from methanol as sole carbon source. We selected over 10 lactate dehydrogenase genes from different organism and introduced them into P. pastoris to produce lactate. To further improve the titer, we tried different cultivation conditions, which resulted in a lactate titer of 693 mg/l. Additionally, considering the reversibility of lactate dehydrogenase might limit the lactate production, we also constructed an irreversible methylglyoxal pathway to produce lactate from methanol. This study provides alternative lactate bioproduction pathways utilizing a renewable resource.