Figure 2. Engineering production of C22 VLCFAs by FA chain-length control in yeast.
(a) Schematic overview of two strategies for chain length control towards VLCFAs. The dotted lines indicate multiple steps and solid lines a single step. Overexpressed genes are shown in blue (endogenous) or green (heterologous). Competitive pathways were eliminated by deleting corresponding genes (marked with X). Elo1, Elo2 and Elo3, yeast FA elongases 1, 2 and 3; MbFAS, FAS I system from Mycobacterium; ScFAS, S. cerevisiae FAS. (b) GC–MS analysis of docosanoic acid (C22:0 FAME) generated by yeast elongation system in strains TY001 (JV03 elo3Δ) and TY002 (JV03 elo3Δ pELO2). Statistical analysis was performed using a Student’s t-test (one-tailed; *P<0.05; **P<0.01 and ***P<0.001; two-sample unequal variance). At least two independent measurements were performed for each experiment and the mean±s.d. of three biological replicates of a representative measurement is shown. (c) GC–MS analysis of docosanoic acid generated in strain TDY7005 (MATa lys2 ura3–52 trp1Δ leu2Δ elo2Δ::kanMX elo3Δ::TRP1/pELO3) and strain TY004 (MATa lys2 ura3–52 trp1Δ leu2Δ elo2Δ::kanMX elo3Δ::TRP1/pGPD415-MvFAS-AcpS). Statistical analysis was performed using a Student’s t-test (one-tailed; *P<0.05, **P<0.01 and ***P<0.001; two-sample unequal variance). At least two independent measurements were performed for each experiment and the mean±s.d. of three biological replicates of a representative measurement is shown. All cells were grown as described in experimental procedures.