TY - JOUR
T1 - Elucidation of triacylglycerol catabolism in Yarrowia lipolytica
T2 - How cells balance acetyl-CoA and excess reducing equivalents
AU - Worland, Alyssa M.
AU - Han, Zhenlin
AU - Maruwan, Jessica
AU - Wang, Yu
AU - Du, Zhi Yan
AU - Tang, Yinjie J.
AU - Su, Wei Wen
AU - Roell, Garrett W.
N1 - Publisher Copyright:
© 2024 International Metabolic Engineering Society
PY - 2024/9
Y1 - 2024/9
N2 - 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 13C-metabolic flux analysis (13C-MFA), genome-scale modeling, and transcriptomics analyses to investigate Y. lipolytica W29 growth with oleic acid, glycerol, and glucose. Transcriptomics data were used to guide 13C-MFA model construction and to validate the 13C-MFA results. The 13C-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.
AB - 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 13C-metabolic flux analysis (13C-MFA), genome-scale modeling, and transcriptomics analyses to investigate Y. lipolytica W29 growth with oleic acid, glycerol, and glucose. Transcriptomics data were used to guide 13C-MFA model construction and to validate the 13C-MFA results. The 13C-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.
KW - C-metabolic flux analysis
KW - Genome-scale model
KW - Glyoxylate shunt
KW - Lipid catabolism
KW - Mannitol cycle
KW - NADPH
KW - Yarrowia lipolytica
UR - http://www.scopus.com/inward/record.url?scp=85198031010&partnerID=8YFLogxK
U2 - 10.1016/j.ymben.2024.06.010
DO - 10.1016/j.ymben.2024.06.010
M3 - Article
C2 - 38942196
AN - SCOPUS:85198031010
SN - 1096-7176
VL - 85
SP - 1
EP - 13
JO - Metabolic Engineering
JF - Metabolic Engineering
ER -