Effects of CO2 concentration and light intensity on macromolecules accumulation of Micractinium sp.

Economically efficient biomass production is crucial to lift the microalgal circular bioeconomy requiring low production cost with higher biomass and value-added products. In this study, Micractinium sp. YACCYB505 was cultured at different illuminations (1600, 2400, 3200 lux) and CO2 conditions (up to 10%) to evaluate biomass productivity and accumulation of macromolecules (lipid, carbohydrate and protein). The product optimization study was conducted to analyze individual variables of environmental factors by using a Box-Behnken design. Highlight intensity (3200 lux) and 5% CO2 aeration maximized biomass productivity on 11th day of microalgal harvest. Microalgal lipid accumulation indicated positive impact on increased CO2 aeration and light intensity treatment. Similarly, a considerable amount of protein content (9%) was increased at higher CO2 aeration but raised light intensity had a negative impact on protein biosynthesis. Significant carbohydrate content reduction was observed with increased light intensity and CO2 aeration. The overall results proved that increased CO2 concentration (10%) and light intensity (3200 lux) enhanced lipid accumulation (32%) and biomass productivity in Micractinium sp., which provides potential to achieve a sustainable, cost-effective biomass and value-added products.