Biocatalytic optimization: Performance and mechanism of molecular sieve composite aluminum-calcium oxides in tobacco biomass pyrolysis

In recent years, China has faced challenges such as energy shortages and environmental pollution. Metal oxides, as biocatalysts, offer promising solutions for biomass energy conversion by enhancing biochemical reaction rates, reducing energy consumption, and improving biomass conversion product quality. This study focuses on using metal-based biocatalysts in the pyrolysis of tobacco, a key cash crop. We prepared aluminum/calcium composite molecular sieves through extraction, calcination, and acid leaching of metal ores. These biocatalysts optimized the tobacco pyrolysis process, improving the composition of bioactive components in the products. Results showed that metal oxide composites effectively facilitated the cleavage and reorganization of tobacco biomolecules, influencing the structure and composition of pyrolysis gases. The presence of alkali metals led to earlier cleavage of tobacco at lower temperatures and increased pyrolysis gas concentration. Specifically, calcium or aluminum increased total weight loss in the 100–300 ℃ range while decreasing maximum weight loss, leading to higher concentrations of low-temperature pyrolysis gases. The optimal catalyst-to-tobacco mass ratio was 2:1 at 500 ℃, maximizing nicotine content, reducing ester formation, and enhancing hydrocarbon biosynthesis. This low-temperature pyrolysis method efficiently releases aroma substances and improves smoke concentration. It offers a practical approach for biomass energy conversion and bioactive substance extraction, providing new insights into metal-based biocatalysts’ role in complex biomass systems.