Rhodococcus opacus is a bacterium that
has a high
tolerance to aromatic compounds and can produce significant amounts
of triacylglycerol (TAG). Here, we present iGR1773, the first genome-scale
model (GSM) of R. opacus PD630 metabolism based on
its genomic sequence and associated data. The model includes 1773
genes, 3025 reactions, and 1956 metabolites, was developed in a reproducible
manner using CarveMe, and was evaluated through Metabolic Model tests
(MEMOTE). We combine the model with two Constraint-Based Reconstruction
and Analysis (COBRA) methods that use transcriptomics data to predict
growth rates and fluxes: E-Flux2 and SPOT (Simplified Pearson Correlation
with Transcriptomic data). Growth rates are best predicted by E-Flux2.
Flux profiles are more accurately predicted by E-Flux2 than flux balance
analysis (FBA) and parsimonious FBA (pFBA), when compared to 44 central
carbon fluxes measured by 13C-Metabolic Flux Analysis (13C-MFA). Under glucose-fed conditions, E-Flux2 presents an R
2 value of 0.54, while predictions based on
pFBA had an inferior R
2 of 0.28. We attribute
this improved performance to the extra activity information provided
by the transcriptomics data. For phenol-fed metabolism, in which the
substrate first enters the TCA cycle, E-Flux2’s flux predictions
display a high R
2 of 0.96 while pFBA showed
an R
2 of 0.93. We also show that glucose
metabolism and phenol metabolism function with similar relative ATP
maintenance costs. These findings demonstrate that iGR1773 can help
the metabolic engineering community predict aromatic substrate utilization
patterns and perform computational strain design.