Abstract

Using a modification of the Bangladesh 3 medium, dose response analysis was carried out to evaluate the effect of certain parameters on biomass production and protein biosynthesis in a Spirulina sp. isolated from an oil-polluted flame pit. A set of conditions described as optimized was compared with another set of conditions described as normal. The optimized parameters include pH 9.0, temperature 30^oC, 0.30 mg/L SO₄^-2, 0.008 mg/L P0₄^3-, 2.0 g/L HC0₃^-, 25 mg/L N0₃^2-, 1.0% Cl^- and light intensity 15 µEm^-2s^-1. Agitation was achieved through aeration using an aquarium pump to supply air at ca 150 bubbles min^-1. Biomass and protein produced were significantly (P = 0.05) higher in the optimized than in the normal condition; that is, biomass and protein produced in optimized condition were 22.7 and 25.8%, respectively, higher than those produced in normal growth condition. The total amino acid concentration in optimized condition was 58.7% higher than in normal conditions. These results show that cultivating the Spirulina species at these optimized environmental conditions could significantly improve biomass yield and protein synthesis in the organism.

Key words: Optimal parameters, optimized condition, normal condition, biomass, protein biosynthesis, environmental factors, Spirulina.