Bioeconomy of microalgae-based processes and products

Various microalgae species, including Chlorella vulgaris, Spirulina platensis, and Nannochloropsis gaditana, have significant potential for biofuel production through thermochemical processes such as pyrolysis, gasification, and hydrothermal liquefaction (HTL). These processes convert algal biomass into bio-oil, syngas, and biochar, offering a renewable alternative to fossil fuels. Pyrolysis typically occurs at temperatures between 400°C and 600°C in the absence of oxygen, while gasification operates at higher temperatures (700°C-1000°C) with limited oxygen to produce syngas. HTL, conducted in subcritical or supercritical water, operates at temperatures of 250°C-350°C and pressures of 10-25MPa. The higher heating value of bio-oil derived from microalgae ranges between 30 and 40 MJ/kg, depending on the specific conversion process and algal species used. In addition to thermochemical methods, biochemical conversion processes such as fermentation contribute to the production of bioethanol, biobutanol, and other bio-based chemicals. Microalgae also play a key role in a diversified bioproduct portfolio, generating polymers, pigments, and high-value chemicals with applications in pharmaceuticals, nutraceuticals, and materials science. These attributes underscore the bioeconomic value of microalgae, highlighting their potential for advancing a sustainable future.