Improvement of Euglena gracilis Paramylon Production through a Cocultivation Strategy with the Indole-3-Acetic Acid-Producing Bacterium Vibrio natriegens.

We investigated the putative effects on the growth and paramylon production of of cocultivation with heterotrophically cocultivated with displayed significant increases in biomass productivity and paramylon content. In addition, the effects of the bacterial inoculum density and the timing of inoculation on the growth of were examined, to determine the optimal conditions for cocultivation. With the optimal deployment of , biomass productivity and paramylon content were increased by more than 20% and 35%, respectively, compared to those in axenic cultures. Interestingly, indole-3-acetic acid biosynthesized by was responsible for these enhancements of The morphology of cocultured cells was assessed. Paramylon granules extracted from the cocultivation were significantly larger than those from axenic culture. Our study showed that screening for appropriate bacteria and subsequent cocultivation with represented an effective way to enhance biomass and metabolite production. has attracted special interest due to its ability to excessively accumulate paramylon. Paramylon is a linear β-1,3-glucan polysaccharide that is the principal polymer for energy storage in The polysaccharide features high bioactive functionality in the immune system. This study explored a new method to enhance the production of paramylon by , through cocultivation with the indole-3-acetic acid-producing bacterium The enhanced production was achieved indirectly with the phytohormone-producing bacteria, instead of direct application of the hormone. The knowledge obtained in this study furthers the understanding of the effects of on the growth and physiology of .