Figure 5

Cross-feeding interactions improve growth. (A) Predicted relative benefit of the co-culture consisting of the mutant b2779 and b0721on glucose for various initial population ratios. Maximum relative benefit (23%) is achieved with an initial population composition of 1:9 for b2779:b0721. The mutant b0114 is the most efficient monoculture on glucose and no strain community has been found to perform better than this monoculture. Thus, we refer to relative benefit here. (B) The acetate exchange flux profiles of each mutant in the co-culture of b2779 and b0721 as they co-grow on glucose. When glucose is exhausted, the produced acetate is exclusively consumed by the mutant b2779. (C) A schematic diagram of the cross-feeding interactions between the mutant b0721 and b2779 on glucose is shown. The mutant b0721 plays the role of a provider. (D) Predicted relative (and absolute) benefit of the co-culture consisting of the mutant b2276 and b3708 on glycolate for various initial population ratios. Maximum group performance (equals to 14%) is observed when the two mutants exhibit equal final frequency in the population, which is achieved with an initial population composition of 1:9 for b3708:b2276. The mutant b3708 is metabolically similar to the wild-type. (E) The acetate exchange flux profiles of each mutant in the co-culture of b2276 and b3708 as they grow on glycolate. As long as the metabolism of glycolate takes place, acetate is produced by b2276 and consumed by b3708. (F) A schematic diagram of the cross-feeding interactions between the mutant b2276 and b3708 on glycolate is shown.