Evaluation of Tetraselmis, Nannochloropsis, and Pseudo-Nitzschia strains in a photobioreactor for biomass and lipid yields toward biodiesel production

This study evaluates three microalgal strains— Tetraselmis sp . ( T. sp.), Nannochloropsis sp . ( N. sp.), and Pseudo-Nitzschia sp. ( P-N sp.)—for biomass and lipid production in a custom-designed airlift photobioreactor adapted to Jordan’s semi-arid conditions. The reactor incorporated internal lighting and airlift mixing to support growth under variable environments. Experiments included strain screening, cultivation in Bold 3N and sludge-based media, CO₂ enrichment, and lipid extraction. T. sp. . demonstrated superior growth (0.371 g/L) and adaptability, while N. sp . and P-N sp. . showed longer lag phases and lower yields, consistent with previous reports. Bold 3N medium sustained stable growth compared to sludge, which gave inflated initial readings due to suspended solids. CO₂ enrichment at 0.6 Liter per minute (LPM) for 60 minutes/day enhanced biomass by 42%. A rapid, single-step lipid extraction method yielded 21.5% oil by dry weight and was faster and more efficient than the Soxhlet extraction method. Fatty acid analysis confirmed suitability for biodiesel (palmitic, stearic, oleic, and linoleic acids). This work demonstrates the practical adaptation of photobioreactor technology to regional conditions, bridging core algal physiology research with localized biofuel applications.