Improvising Biodiesel Production from Scenedesmus dimorphus via Nutrient Starvation and Optimized Pretreatment Process

Microalgae show great potential as a biodiesel feedstock, primarily attributed to their rapid growth rates and higher lipid content. Biomass pretreatment is a critical step in biodiesel production, as it is essential for providing unsaturated and saturated fatty acids to produce fatty acid methyl ester (FAME). The present study investigates the effect of two-stage cultivation of nutrient starvation and ultrasonic-assisted solvent extraction technique from Scenedesmus dimorphus on lipid content and productivity. Preliminary studies facilitated the identification of an appropriate range to which the variables must be optimized. Scenedesmus dimorphus was obtained from the National Repository for Microalgae and Cyanobacteria [NRMC-F]. The medium optimization resulted in a higher lipid content (38.45%) in the M4N medium under starved conditions. The generated model (R² = 0.998) forecasted the lipid content of 0.317 g/L after 87.19 min of sonication under the sonication power (65.77 W) with a molar ratio [chloroform:methanol] (1.3:1), which was experimentally validated. Under optimized conditions, the efficiency of extraction has been improved from 64.6 to 72.5% with a maximum biodiesel yield of 25.4 wt.%. In summary, this research successfully identified the optimal growth medium and pretreatment conditions, ultimately maximizing the production of biodiesel.

Graphical Abstract