The Growth Performance of Spirulina platensis on Media Supplemented with Digested Poultry Droppings Slurry of Biogas Plant

Abstract

Background: The growth performance of Spirulina platensis, a type of blue-green algae known for its high nutritional value, on media supplemented with poultry droppings slurry from a biogas plant can be an intriguing study. Poultry droppings slurry, a by-product of biogas production, is rich in organic matter and nutrients, potentially serving as a cost-effective alternative to conventional nutrient sources for Spirulina cultivation. Using poultry-dropping slurry as a nutrient source for large-scale Spirulina cultivation potentially offers sustainable solutions for both waste management and the production of valuable biomass for various applications, including food, feed, and biofuel.Objectives: The present study was undertaken to utilize poultry droppings biodigested slurry from a biogas plant as an organic additive for S. platensis cultivation. S. platensis was mass multiplied with the traditional Zarrouk media as a control and supplemented organically or additionally by the available poultry dropping spent of a methane plant and Zarrouk media.Materials and Methods: Two treatments were carried out for this study. The control reactor consisted of Zarrouk’s medium with inoculated S. platensis alone, and the experimental reactor contained poultry droppings supplemented with 9 g of Zarrouk’s media and inoculated with S. platensis in duplications for about 35 days. The growth of S. platensis was measured using apparent turbidity and crude phycocyanin. Also, Direct Microscopic Count (DMC), crude protein, dry weight, biomass concentration, Electrical Conductivity (EC), pH, chlorophyll-a, and carbohydrate were additional metrics.Results: The findings showed that, compared to the control, the supplement treatment of poultry droppings bio slurry with Zarrouk’s media had greater dry weights (2.01 g/L), growth rates (3.44 at 750 nm), protein levels (321 μg/mg), and phycocyanin (2.89 at 680 nm).Conclusion: These findings highlighted the potential of integrating waste-to-resource approaches in microalgae cultivation, contributing to sustainable solutions for both waste management and the production of valuable biomass for various applications. Further research is warranted to optimize cultivation parameters and scale up production for commercial applications.

Keywords: Spirulina platensis; Spent bio digested slurry; Poultry droppings; Zarrouk’s media; Protein content; Phycocyanin; Biomass concentration; Electrical conductivity