Evaluating the toxicity of methanol, formaldehyde and formate on the growth fitness of Yarrowia lipolytica

Liquid C1 feedstock, including methanol, formaldehyde and formate can be easily manufactured from greenhouse gases CO 2 and CH 4 . Yarrowia lipolytica , isolated from marine ecosystem, is a non-conventional yeast which is capable of assimilating multiple range of hydrophobic compounds including alcohols, lipids, hydrocarbons, and volatile fatty acids. This yeast has been extensively engineered as a benchmark host to produce lipids, resveratrol, carotenoids, squalene and other natural products. Connecting C1 feedstock pathways to these important metabolites holds promise to further reduce costs and improve sustainability. Herein we tested the growth fitness of Y. lipolytica when exposed to various one-carbon (C1) liquid feedstocks (methanol, formaldehyde, and formate). We firstly examined the cell growth kinetics with an automatic Cell Growth Analyzer and fitted the data with a Monod-type growth model. We obtained the inhibition constants of the three liquid C1s from the growth fitness dose-response curves. We found that the lagging phase duration is exponentially correlated with the toxicity of the tested C1 solvents. Notably, Y. lipolytica exhibited tolerance to methanol (IC 50 871 mM) and formate (IC 50 42.6 mM), but showed sensitivity to formaldehyde (IC 50 3.8 mM). We further demonstrated that glucose and formate co-substrate could improve cell growth and lipid production. This work broadens Y. lipolytica ’s substrate scope and facilitates sustainable and cost-efficient production of fuels and chemicals from C1 feedstocks.