Optimization of medium components using orthogonal arrays for γ-Linolenic acid production by Spirulina platensis

Abstract

This work describes the medium optimization of γ-Linolenic acid (GLA) production by Spirulina platensis using one-factor and orthogonal array design methods. In the one-factor experiments, NaHCO₃ (9 mg L⁻¹), NaNO₃ (13.5 mg L⁻¹) and MgSO₄·7H₂O (11.85 mg L⁻¹) proved to be the best components for GLA production. The optimal pH for GLA production by the alga was 9.2. Based on the delta values, NaHCO₃ showed the greatest effect on the GLA production of the various factors tested, followed in decreasing order by MgSO₄·7H₂O, NaNO₃ and K₂SO₄. The maximum GLA yield obtained was 19.2 mgL⁻¹ in the presence of optimum concentrations of NaHCO₃ (20 g L⁻¹), NaNO₃ (3 g L⁻¹), MgSO₄·7H₂O (0.5 g L⁻¹) and K₂SO₄ (1.5 g L⁻¹). Because of the slow growth rate of the algae, the practice of robust orthogonal array methods during the optimization of medium components can result in the production of an optimal biomass and a higher GLA yield for nutraceutical applications.