Computation of constrained MCSs leading to coupled ethanol and biomass formation by E. coli under anaerobic growth on glucose.

Constrained MCSs up to size 7 that lead to ethanol synthesis with high yield in E.coli while slow growth is possible. Four scenarios were considered differing in the maximal glucose uptake rate (; given in mmol/(gDW⋅h)) or/and in the demanded minimal ethanol yield (; given in molecules ethanol per molecules glucose) in the strain to be constructed. The total number of MCSs (#MCSs) refers to knock-out sets blocking flux vectors with low ethanol yield; the number of constrained MCSs (#cMCSs) refers to the subset of MCSs which allow in addition growth above the minimum threshold (for details see text). For the cMCSs found, the distribution over cut set sizes are also shown (no cMCSs with less than 3 cuts exist; the upper limit of cuts was set to 7).The full/reduced networks contain 1668/564 metabolites and 2382/958 reactions (the reactions in the compressed network represent lumped reaction subsets). For computation 12 threads on a cluster node with two Intel Xeon DP X5650 processors (each 6 cores) were used.