Effect of gibberellin, methyl jasmonate and myoinositol on biomass and eicosapentaenoic acid productivities in the eustigmatophyte Monodopsis subterranea CCALA 830

Abstract

Omega-3 fatty acids sourced from microalgae are in demand due to their therapeutic potential and sustainability of the source. The present study was focused towards enhancing eicosapentaenoic acid (EPA) productivity in the marine Chrysophyte Monodopsis subterranea through media supplementation using the plant growth regulators gibberellic acid, methyl jasmonate and myoinositol. The effect of three concentrations (1 μM, 10 μM and 100 μM) of supplements on biomass yield, fatty acid composition, total fatty acid (TFA) and EPA productivity were analyzed at three phases of microalgal growth. Supplementation with 100 μM GA increased biomass yield and TFA productivity by 3.3-fold and 3.9-fold respectively at the mid-exponential phase and EPA productivity increased up to 3.2-fold at the late-exponential phase. The addition of 1 μM MeJA stimulated biomass accumulation to 2.7-fold at the late-stationary phase, but this effect was reduced to 1.1–1.4-fold at higher concentrations. The addition of 10 μM MI also showed a positive effect on TFA productivity and thus increased EPA productivity by 1.8-fold at the late-stationary phase. Supplementation with 100 μM GA, 100 μM MeJA and 10 μM MI at the late-stationary phase increased all fatty acids except 18:0 and 18:2. EPA was negatively correlated with 18:2 at all three growth phases. Principal components analysis indicated a strong relationship between key fatty acids and EPA at all three growth stages and associated with 100 μM GA.