Comparative Pretreatment Strategies for Efficient Lipid Extraction Followed by the Valorization of Algal Biomass for Biomaterial Production

Industrialization has resulted in a scarcity of energy reserves and an alarming exigency for sustainable fuels. The significant consumption of fossil fuels has caused global warming and detrimental effects on the global economy. Photosynthetic microalgae can serve as both an alternative source of energy and a commercial product. Low lipid extraction yield significantly restricts microalgae from being a viable feedstock at a large scale. Hence, in this study, diverse traditional methods (TMs), including ultrasonication, osmotic shock, microwave, and acid-base hydrolysis, were investigated compared to a novel combinatorial method (NCM) developed for the pretreatment of microalgae biomass. NCM was chosen as the most appropriate strategy as it showcased a 2.2-fold rise in the total lipid yield in contrast with the considerable TMs. Additionally, the defatted algae biomass (DFB) was repurposed to synthesize commercially significant zinc oxide nanoparticles (ZnO, possessing an average size of 295 nm. The synthesized nanoparticles were analyzed by a suite of characterization methods like Scanning electron microscope (SEM), X-ray powder diffraction (XRD), and Dynamic light scattering (DLS) to comprehend the structural and morphological insights. Therefore, the unprecedented work demonstrated the microalgae biorefinery approach for biodiesel application and simultaneous production of ZnO nanoparticles to support a zero-waste approach.