[P002] Poster

1:00 PM - 1:50 PM JST(4:00 AM - 4:50 AM UTC)

[P01-148] Overcoming Metabolic Bottlenecks for Efficient De Novo Melatonin Biosynthesis in Engineered Komagataella phaffii

○yuyao ren^1,2, Yongjin J. Zhou¹ (1. Dalian Institute of Chemical Physics (China), 2. University of Chinese Academy of Sciences (China))

Keywords:

Melatonin,Tryptophan derivatives,Caffeic acid O-methyltransferase,Komagataella phaffii

More than 16% of the global population is estimated to have insomnia, imposing a substantial health and economic burden on society. Melatonin is a key endogenous hormone regulating the circadian rhythm and exhibits clinically meaningful efficacy in managing insomnia. Industrial melatonin production is primarily achieved through chemical synthesis, suffering from limitations including complicated procedures, low yields and poor stereoselectivity. Developments in microbial cell factories offer new routes for sustainable and efficient production of melatonin. Two major metabolic bottlenecks constrain the efficient microbial de novo melatonin synthesis: the limited supply of precursor tryptophan, a structurally complex and energy-demanding aromatic amino acid, and poor efficiency of N-acetyl serotonin methylation by caffeic acid O-methyltransferase (COMT). Here, we introduced heterologous melatonin synthesis pathway in Crabtree-negative yeast Komagataella phaffii. By combinatorial pathway optimization, global metabolism remodeling and rational engineering of COMT, substantially enhancement in the supply of tryptophan and efficiency of N-acetyl serotonin methylation were achieved, leading to a titer of 16.9 mM melatonin from glucose in bioreactor by engineered K. phaffii, representing the highest titer reported to date. Structural and phylogenetic analysis of COMTs demonstrated that the identified sites in the methoxy cavity were highly conserved and played key roles in regulating the substrate scope. Altogether, our work pioneers the high-level de novo production of tryptophan derivatives in yeast and provides new insights into the precise engineering of COMTs.