Evaluation of cultivation conditions in hydrogel systems to enhance Chlorella vulgaris growth

Microalgae have gained significant attention as sustainable alternatives to traditional agriculture and energy resources. The cultivation efficiency of microalgae within hydrogel systems presents a promising avenue for spatially efficient bio-production. However, the optimum cultivation conditions of hydrogel cultivation systems have not been elucidated. This study focused on evaluating the hydrogel-based cultivation of Chlorella vulgaris in symbiosis with Bacillus Strain Salmah Ismail (SI) 139SI. It investigated the impact of hydrogel concentration, pH, light exposure, and system thickness on the growth and chlorophyll production of the algae. Our findings highlighted that, in coculture, a 7% (w/v) hydrogel concentration, pH of 7.4, a 12-h light/dark cycle at a hydrogel concentration of 7% but continuous light exposure under 5% hydrogel concentration, and a system thickness of 10 mm have provided the most favorable environmental conditions for the proliferation and chlorophyll production of C. vulgaris. These conditions significantly enhanced the biomass yields, suggesting that tailored hydrogel environments can substantially improve microalgae productivity.