Macromolecular characterization and growth kinetics of Arthrospira platensis and Chlorella Vulgaris as affected by different media (synthetic and Anaerobic Digestor Effluent) - A comparative study.

Abstract

Background: Global concern about the availability of irrefragable, nutritious food to the masses to eliminate malnutrition had raised interest in microalgae-based dietary supplements. Furthermore, improper disposal of industrial wastewater is contaminating freshwater resources around the world, which is increasing the demand for eco-friendly water recycling strategies. The focus has been shifted to the use of microalgae because of their ability to treat wastewater and their biotechnological applications. Among them, Chlorella Vulgaris and Arthrospira platensis are attracting considerable attention for their effective growth on wastewater and their nutritional value and use in biofuel production.
 Methodology: Cultures of C. Vulgaris and A. platensis were subjected to different growth conditions to analyze their growth kinetics and biomass production in their respective synthetic media and Anaerobic Digestor Effluent (ADE). The biomass produced was further analyzed for its protein (Lowry method), carbohydrate (phenol-sulfuric method), and lipid (Bligh and Dyer method) content. 
 Results: The results obtained through the growth kinetics study showed that C. Vulgaris and A. platensis display a better growth rate on ADE at higher light intensities as compared to cultures growing on synthetic media. Significantly different levels of protein, carbohydrate, and lipid were also reported. C. Vulgaris grown on ADE had 78.5% protein content compared to 62% achieved in F/2 medium. Similarly, 7.6% of carbohydrate content was achieved in ADE compared to 6% in F/2. Lipid content however was much higher in F/2 (22%) compared to ADE (13%). The culture of A. platensis grown on ADE had 84% protein content compared to 71% achieved in Zarrouk’s medium. Similarly, 11.7% of carbohydrate content was achieved in ADE compared to 16.6% in Zarrouk’s. Lipid content in A. platensis was found to be very low (3%). 
 Conclusion: The present study builds an understanding of the relationship between different factors contributing to economical microalgae production and macromolecular characterization of the targeted microalgae for analyzing its potential applications and uses. The study further suggests the added advantage of cost-effective production of algal biomass with an added advantage of phycoremediation using ADE as growth media.