Advances in algal biofuel production through catalysts and nanocatalysts: anintegrated chemical, biochemical, and physical analysis

Biofuel has emerged as one of the most promising alternatives to petroleum-derived fuels, particularly in the current context of rapidly depleting fossil fuel reserves. The combustion of fossil-based fuels poses serious risks to both the environment and human health due to the release of greenhouse gases. This study aimed to assess the fatty acid methyl ester (FAME) composition, viscosity, acid number, and chemical metal elements present in algal biodiesel produced through a transesterification bioprocess. Nanoparticles (NPs) offer a promising solution to current challenges in biomass utilization. Their advantages include high selectivity, energy efficiency, effective time management, and reduced costs. Biodiesel conversion yield, along with its physical and chemical properties, was analyzed using GC-MS and a multi-element oil analyzer. The highest conversion yield of 98.9% was achieved using a mixed catalyst-nanocatalyst system (NaOH + CaO + ZnO) under optimal conditions: a 1:4 oil-to-methanol volumetric ratio, 1.0% catalyst concentration, reaction temperature of 40°C, and stirring speed of 320 rpm. A significant difference was observed in the viscosity and acid value between biodiesel produced using a single catalyst and that produced using catalyst mixtures. Furthermore, the concentrations of chemical metal elements (Na, Ca, Mg, Cu, Fe, Zn, Ag, Al, P, Pb, B, Cr, Mn, Sn, Mo, Si, Ba, Ni, Ti, and V) were lower in biodiesel derived from mixed nanocatalyst-catalyst combinations (NaOH + ZnO, NaOH + CaO, and NaOH + CaO + ZnO) compared to the single-catalyst system (NaOH). Overall, biodiesel produced using the combined catalyst and nanocatalyst approach exhibited reduced metal element content and superior yield compared to biodiesel obtained using a single catalyst. In addition, nanomaterials such as nanocatalysts have been found to be cost effective as well as stable catalysts for enzyme immobilization, thus improving biofuel synthesis.