Integrated biorefinery approach for sustainable production of biodiesel, bioplastics and high value bioproducts from a bloom forming alga, Botryococcus braunii.

The global shift towards sustainable energy and bioproducts has intensified research on algae. Renewable green biofuel can address and provide solutions to both energy crisis and climate change challenges. Botryococcus braunii, a bloom forming green microalga, known for its high lipid content and potential for biofuel production has been explored in the present study. The study envisages the utilisation of algal blooms in freshwater ecosystems for the production of biodiesel and high value bioproducts through an integrated biorefinery approach. During the peak bloom, the algal cell densities reached up to 3.3 × 10 colonies L with significant shift in water quality due to high nutrient uptake. Gas chromatography-mass spectroscopic analysis revealed high concentration of saturated and monounsaturated fatty acids, particularly hexadecanoic acid (C16:0) and 9-octadecenoic acid (C18:1) which are essential for stable, energy-rich biodiesel production. Hydrocarbons including squalene, botryococcenes, and botryococcane, produced by this alga have significant industrial applications. The high polyhydroxybutyrate (PHB) content in the alga emphasises its potential for sustainable bioplastic production. Growth conditions, lipid content, and biochemical composition of B. braunii were investigated. Algal blooms can provide a sustainable and economically viable source of biofuel with high value co-products. This approach not only contributes to renewable energy solutions through valorising a waste bioresource but in combination with other mass cultivation strategies can also offer a means to sustainably manage the impact of algal blooms on aquatic ecosystems.