Thermochemical and biochemical routes for sustainable biofuel production: A review

The rising demand for sustainable energy is driving attention in biomass as a renewable alternative to fossil fuels. This review explores biomass composition, pretreatment methods, and main conversion technologies, including pyrolysis, gasification, and fermentation. Biochemical methods such as enzymatic hydrolysis and fermentation enable bioethanol, biobutanol, and biogas production. Conversion efficiency depends on factors like feedstock properties, pretreatment methods, and reactor configurations. Thermochemical processes, particularly pyrolysis, effectively convert lignocellulosic biomass into bio-oil, syngas, and biochar. Product distribution is strongly dependent on operating parameters such as reactor type, temperature, heating rate, and biomass feedstock properties. Under optimized fast pyrolysis conditions at 450–600 °C and rapid heating with short vapor residence time, typical yields include 60–75 wt% bio-oil, 10–20 wt% biochar, and 10–25 wt% syngas. Emerging techniques, such as microwave-assisted pyrolysis, have shown promise in improving fuel quality and reducing process residues. Overall, biomass conversion technologies represent a viable pathway toward sustainable energy production, offering significant potential to reduce greenhouse gas emissions and reliance on fossil resources.