摘要：SummaryThe production of coenzyme B12using well-characterized microorganisms, such asEscherichia coli, has recently attracted considerable attention to meet growing demands of coenzyme B12in various applications. In the present study, we designed an auxotrophic selection strategy and demonstrated the enhanced production of coenzyme B12using a previously engineered coenzyme B12-producingE. colistrain. To select a high producer, the coenzyme B12-independent methionine synthase (metE) gene was deleted inE. coli, thus limiting its methionine synthesis to only that via coenzyme B12-dependent synthase (encoded bymetH). Following the deletion ofmetE, significantly enhanced production of the specific coenzyme B12validated the coenzyme B12-dependent auxotrophic growth. Further precise tuning of the auxotrophic system by varying the expression ofmetHsubstantially increased the cell biomass and coenzyme B12production, suggesting that our strategy could be effectively applied toE. coliand other coenzyme B12-producing strains.Graphical AbstractDisplay OmittedHighlights•The auxotrophic selection strategy was applied to coenzyme B12production•Coenzyme B12-independent methionine synthase was deleted for auxotroph system•The auxotrophic strategy could significantly enhance the coenzyme B12production•Optimization of the auxotroph system further enhanced the coenzyme B12productionBiological Sciences; Bioengineering; Metabolic Engineering
