Improving carbon-reduced catalytic gasification of microalgae for biohydrogen production

To realize efficient biohydrogen production from microalgal biomass, catalytic gasification under optimized conditions was employed in this study for enhanced biohydrogen yield. Initially, the biochemical characteristics of C. vulgaris cultivated under stress conditions was investigated and then correlated with syngas production through the principal component analysis (PCA) to explore their effects on biohydrogen production. Subsequently, CaO catalyst-mediated catalytic gasification was developed and applied to convert C. vulgaris biomass to renewable biohydrogen with reduced carbon emission. The central composite design (CCD) method and regression analysis were used to optimize two essential gasification parameters, i.e., temperature at 600, 750, and 900 °C and catalyst loading with 0, 20, and 100 wt%, and also to investigate their synergetic effects on algae-to-biohydrogen conversion. The results demonstrated that microalgal biochemical compositions exerted obvious effects on subsequent biohydrogen production, especially enhanced lipid composition promoted biohydrogen yield. Further parameter optimization, particularly catalyst loading, was able to significantly improve H₂ production while reducing CO₂ generation. This study provides valuable insights into carbon-reduced biohydrogen production from renewable microalgal biomass for future sustainability development.