Heterotrophic culture of Spirulina platensis improved its growth and the study of its nutritional effect

With the development of human civilization, many people in the world still suffer from hunger due to wars, epidemics, and other causes such as not being able to afford a healthy diet. As a food, raw material with huge market potential, Spirulina platensis can be used as a new resource for food and has been in large-scale industrialized production worldwide. However, one of the biggest limitations to growing microalgae on an industrial scale is the high cost of the culturing medium. To reduce the culture cost, we hypothesized that S. platensis could grow better in a medium supplemented with glucose. In this study, we investigated the effects of Zarrouk’s medium, Central Food Technological Research Institute (CFTRI) medium, and CFTRI with glucose on the growth rate and biomass of S. platensis. Our results showed that compared with the expensive Zarrouk’s medium containing trace elements, adding a small amount of glucose to the low-cost CFTRI medium significantly increased S. platensis’s growth rate and biomass. Then, to further reduce breeding costs, we continued to explore the growth of S. platensis in a CFTRI medium supplemented with glucose under dark conditions. Our statistical data showed that the heterotrophic glucose consumption of S. platensis was affected by light, and the growth of S. platensis was limited in the absence of light. Finally, we used Drosophila melanogaster to verify the function of S. platensis and found that S. platensis supplementation increased longevity and reproductive ability in fruit flies.