Design of hybrid biosystem: Triple algal co-culture model for green biorefineries

In this study a triple algal co-culture model comprising Haematococcus pluvialis (H), Chlorella vulgaris (C), and Spirulina platensis (S) was implemented to address the challenges in biorefineries. The co-culture model was designed based on the key assumptions regarding the growth dynamics of each algal species. The primary objective was to analyze how different inoculum ratios affect co-culture productivity and compare the results with those obtained from monoculture systems. The highest biomass concentration of 1.60 +/- 0.02 g L-1, corresponding to a growth rate of 0.088 day-1, was achieved at the inoculation ratio of 5:1:1 H:C:S. Phycocyanin, carotenoid and lipid yields were 5.18 +/- 0.01 mg g(-)1 DW, 8.39 +/- 1.2 mg g-1 DW, and 0.22 +/- 0.02 g g-1 DW at the inoculation ratio of 5:1:1 H:C:S, respectively. At the ratio of 5:1:1 H:C:S, phycocyanin productivity was 1.9-fold higher than that of the S. platensis monoculture, carotenoid productivity was 1.4-fold higher than that of the H. pluvialis monoculture, and lipid productivity was 1.1-fold higher than that of the C. vulgaris monoculture. These results show that the concurrent production of multiple high-value bioproducts enhances cost efficiency and environmental sustainability, while minimizing the spatial, temporal, and labor demands of the biorefinery process.