Effect of CO2 Concentration on Growth and Biochemical Composition of Newly Isolated Indigenous Microalga Scenedesmus bajacalifornicus BBKLP-07

Abstract

Photosynthetic mitigation of CO₂ through microalgae is gaining great importance due to its higher photosynthetic ability compared to plants, and the biomass can be commercially exploited for various applications. CO₂ fixation capability of the newly isolated freshwater microalgae Scenedesmus bajacalifornicus BBKLP-07 was investigated using a 1-l photobioreactor. The cultivation was carried at varying concentration of CO₂ ranging from 5 to 25%, and the temperature and light intensities were kept constant. A maximum CO₂ fixation rate was observed at 15% CO₂ concentration. Characteristic growth parameters such as biomass productivity, specific growth rate, and maximum biomass yield, and biochemical parameters such as carbohydrate, protein, lipid, chlorophyll, and carotenoid were determined and discussed. It was observed that the effect of CO₂ concentration on growth and biochemical composition was quite significant. The maximum biomass productivity was 0.061 ± 0.0007 g/l/day, and the rate of CO₂ fixation was 0.12 ± 0.002 g/l/day at 15% CO₂ concentration. The carbohydrate and lipid content were maximum at 25% CO₂ with 26.19 and 25.81% dry cell weight whereas protein, chlorophyll, and carotenoid contents were 32.89% dry cell weight, 25.07 μg/ml and 6.15 μg/ml respectively at 15% CO₂ concentration.

Keywords: Biochemical parameter; CO2 fixation; Green algae; Growth kinetics; Scenedesmus bajacalifornicus.