Structure, mechanism and regulation of an artificial microbial ecosystem for vitamin C production

At present, the modern two-step fermentation process is one of the major approaches for the industrial production of vitamin C. The key step in this process is the conversion of L-sorbose to 2-keto-L-gulonicacid (2-KLG), the vitamin C precursor, which is accomplished by an artificial microbial ecosystem consisting of Ketogulonicigenium vulgare and Bacillus megaterium. This review describes current progress in understanding this ecosystem, not only the individual physiological characteristics of the two strains, but also the interactions between them. Special emphasis is placed on recent systems biology studies of the ecosystem. We also discuss the regulation and improvement of this ecosystem, including analysis of the fermentation medium components and genetic engineering and optimum fermentative strategies. Finally, perspectives on the knowledge and engineering of this important artificial microbial ecosystem are discussed.