Efficient Bioproduction of 3-Hydroxypropionic Acid from Methanol by a Synthetic Yeast Cell Factory

Methanol is an ideal feedstock for bio-manufactur-ing chemicals without the dependence of sugars and the competition of arable lands. We here engineered an industrial yeast Pichia pastoris to efficiently produce 3-hydroxypropionic acid (3-HP) from sole methanol as a carbon source by using a malonyl-CoA-derived pathway. Optimizing the expression of malonyl-CoA reductase gene MCR from Chloroflexus aurantiacus and enhancing the supply of precursors and NADPH enabled 3-HP production of 1.5 g/L. To avoid the time-consuming genetic manipulation, metabolically transforming a free fatty acid (FFA)-overproducing strain toward 3-HP biosynthesis results in a 3-HP production of 1.9 g/L in a shake flask. Through further downregulation of methanol dissimilation, 3-HP production was improved to 2.2 g/L. Subsequent fed-batch cultivation in bioreactors achieved a remarkable 3-HP production of 48.2 g/L from minimal medium with a yield of 0.23 g/g methanol. Notably, this represents the highest reported 3-HP production from one-carbon (C1) feedstocks and is comparable to that from sugar in yeast. The high-level 3-HP production from methanol highlights the potential of P. pastoris as a workhorse for methanol biotransformation. Furthermore, the strategies presented in this study could be applied for production of other acetyl-CoA derivatives from methanol in P. pastoris.

Automated summary

Genetically modified industrial yeast Pichia pastoris was engineered to efficiently produce 3-hydroxypropionic acid (3-HP) from methanol. Through optimization of gene expression, substrate supply, and NADPH availability, 48.2 g/L of 3-HP was obtained in large-scale bioreactor cultivation. This study highlights the potential of P. pastoris for methanol biotransformation and provides strategies for the production of other acetyl-CoA derivatives from methanol.