1. Elucidation of triacylglycerol catabolism in Yarrowia lipolytica: How cells balance acetyl-CoA and excess reducing equivalents.
- Author
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Worland AM, Han Z, Maruwan J, Wang Y, Du ZY, Tang YJ, Su WW, and Roell GW
- Subjects
- Oleic Acid metabolism, Glucose metabolism, Oxidation-Reduction, Models, Biological, Yarrowia metabolism, Yarrowia genetics, Acetyl Coenzyme A metabolism, Acetyl Coenzyme A genetics, Triglycerides metabolism
- Abstract
Yarrowia lipolytica is an industrial yeast that can convert waste oil to value-added products. However, it is unclear how this yeast metabolizes lipid feedstocks, specifically triacylglycerol (TAG) substrates. This study used
13 C-metabolic flux analysis (13 C-MFA), genome-scale modeling, and transcriptomics analyses to investigate Y. lipolytica W29 growth with oleic acid, glycerol, and glucose. Transcriptomics data were used to guide13 C-MFA model construction and to validate the13 C-MFA results. The13 C-MFA data were then used to constrain a genome-scale model (GSM), which predicted Y. lipolytica fluxes, cofactor balance, and theoretical yields of terpene products. The three data sources provided new insights into cellular regulation during catabolism of glycerol and fatty acid components of TAG substrates, and how their consumption routes differ from glucose catabolism. We found that (1) over 80% of acetyl-CoA from oleic acid is processed through the glyoxylate shunt, a pathway that generates less CO2 compared to the TCA cycle, (2) the carnitine shuttle is a key regulator of the cytosolic acetyl-CoA pool in oleic acid and glycerol cultures, (3) the oxidative pentose phosphate pathway and mannitol cycle are key routes for NADPH generation, (4) the mannitol cycle and alternative oxidase activity help balance excess NADH generated from β-oxidation of oleic acid, and (5) asymmetrical gene expressions and GSM simulations of enzyme usage suggest an increased metabolic burden for oleic acid catabolism., (Copyright © 2024 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.) more...- Published
- 2024
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