فهرست نشریات علمی دسترسی آزاد ایران

Microalgae Haematococcus pluvialis and yeast Xanthophyllomyces dendrorhous are two microorganisms known for their ability to produce astaxanthin, a valuable carotenoid with huge applications in various industries. This study aimed to investigate the optimal culture medium for the coculture of these two species, focusing on providing appropriate nutrients for their growth, particularly before H. pluvialis enters the red phase. Growth curves of H. pluvialis and X. dendrorhous were obtained in their standard media, Bold's Basal Medium (BBM) and Yeast Malt (YM) medium, respectively. Four candidate media were prepared based on BBM and YM constituents: BBM with glucose (BG), BBM with glucose and malt (BGM), BBM with glucose and peptone (BGP), and BBM with glucose and yeast extract (BGY). Cell numbers of both species were compared after 6 days of coculture incubation. Results showed that H. pluvialis exhibited the highest cell densities in BGM and BGY media, reaching 1.22×105 and 1.488×105 cells/mL, respectively. In contrast, the highest growth of X. dendrorhous was observed in BG medium, with a maximum cell density of 3.8 × 105 cells/mL. BGM demonstrated the balanced growth for both species, while BGY resulted in the highest cell concentration for H. pluvialis and controlled the growth of X. dendrorhous. The study highlights the importance of selecting a culture medium that balances the growth of both species and ensures controlled nutrient competition for a productive co-culture system. These findings contribute to the development of efficient co-cultivation strategies to enhance the cell growth rate and productivity.