biostudies-literatureWinkler MHMarie Curie Postdoctoral awardFWOe0172785https://www.ebi.ac.uk/biostudies/studies/S-EPMC5363889biostudies-literatureUnknown12(3)The conditions present in both in vitro and in vivo ecosystems determine the microbial population harbouring it. One commonly accepted theory is that a species with a high substrate affinity and low growth rate (k-strategist) will win the competition against a second species with a lower substrate affinity and higher growth rate (r-strategist) if both species are subjected to low substrate concentrations. In this study two nitrite oxidizing bacteria (NOB), Nitrospira defluvii (k-strategist) and Nitrobacter vulgaris (r-strategist), were cultivated in a continuous reactor systems. The minimal hydraulic retention time (HRT) required for maintaining the slower growing Nitrospira was first determined. A reactor containing Nitrobacter was set to the same HRT and Nitrospira was injected to evaluaPloS oneEffect of the dilution rate on microbial competition: r-strategist can win over k-strategist at low substrate concentration.PMC5363889PIEF-GA-2012-329328Goethals PWinkler MHVolcke EIHahne BBoets PfalseEffect of the dilution rate on microbial competition: r-strategist can win over k-strategist at low substrate concentration.The conditions present in both in vitro and in vivo ecosystems determine the microbial population harbouring it. One commonly accepted theory is that a species with a high substrate affinity and low growth rate (k-strategist) will win the competition against a second species with a lower substrate affinity and higher growth rate (r-strategist) if both species are subjected to low substrate concentrations. In this study two nitrite oxidizing bacteria (NOB), Nitrospira defluvii (k-strategist) and Nitrobacter vulgaris (r-strategist), were cultivated in a continuous reactor systems. The minimal hydraulic retention time (HRT) required for maintaining the slower growing Nitrospira was first determined. A reactor containing Nitrobacter was set to the same HRT and Nitrospira was injected to evalua2017-01-01T00:00:00Z20172025-04-04T09:01:32.51Z2019-03-26T22:49:30ZS-EPMC53638892833396010.1371/journal.pone.0172785