Biomass optimisation and scale-up in photobioreactor by Pediastrum duplex strain KT 003362.1 to produce microalgal lipids for biodiesel production

The hunt for renewable energy sources has become more intense due to rising greenhouse gas emissions and the depletion of fossil fuels. Although microalgae-based biodiesel has shown promise, issues including low biomass productivity, subpar lipid output, and the high cost of photobioreactors limit its widespread use. This work used a locally isolated Pediastrum duplex KT 003362.1 to optimize environmental factors and scale up in a photobioreactor to increase biomass and lipid production. Key cultivation factors, such as temperature, pH, light intensity, photoperiod, and nutritional content, were optimized using a one-factor-at-a-time (OFAT) technique. For scale-up experiments, a locally made 5-L cylindrical glass photobioreactor was built and run under regulated conditions. Gravimetric and solvent extraction techniques were used to measure biomass concentration and lipid content, and gas chromatography–mass spectrometry (GC–MS) was used to assess the quality of biodiesel. Under photobioreactor settings, the optimization procedure produced a maximum biomass concentration of 16.41 ± 0.03 g/L, lipid content of 77.24 ± 0.07%, and biodiesel output of 85.73 ± 0.02%. The existence of essential components appropriate for the production of biodiesel was revealed by fatty acid methyl ester profiling. It was discovered that the biodiesel's physicochemical characteristics fell within ranges that were comparable to recognized international standards. Biomass and lipid productivity were greatly increased by combining low-cost, locally manufactured photobioreactors with optimized growth conditions. The results show Pediastrum duplex KT 003362.1's potential as a sustainable biodiesel feedstock and offer a scalable method of cutting production costs. Biomass yield reached 16.41 ± 0.03 g/L in photobioreactor Lipid content increased to 77.24 ± 0.07% under optimized conditions Biodiesel yield achieved 85.73 ± 0.02% from extracted lipids Low-cost 5 L photobioreactor designed and fabricated for scale-up