Lipase enzyme is covalently anchored onto Fe₃O₄ magnetic nanoparticles (5–15 nm core). The huge surface-to-volume ratio of the nanoparticles packs far more active enzyme per gram of catalyst than a bulk pellet, so the transesterification reaction runs fast even at low catalyst loading — this 2D view solves the exact same kinetics as the 3D reactor, from directly overhead:
Triglyceride + 3 MeOH --lipase--> 3 FAME (biodiesel) + Glycerol
dY/dt = k(T) · A · [1 − Y/Y_max] · (dose / (Km + dose))
k(T) = k0 · exp(−Ea / (R·T)) (Arrhenius rate constant)
A = residual enzyme activity (0–1), decays a few % per magnetic-recovery cycle
- Nanoparticle dose — more catalyst surface area available per liter of oil raises the reaction rate, following Michaelis–Menten-style saturation at high dose.
- Reaction temperature — raises the Arrhenius rate constant k(T) up to ~55 °C; above that a soft denaturation penalty (a separate factor on top of k, not part of the Arrhenius term itself — the underlying k(T) alone never falls with T) cuts the achievable rate, reproducing the classic bell-shaped enzyme activity-vs-temperature curve.
- Stirring rate — improves oil/nanoparticle contact (mass transfer); too little stirring starves the reaction even with catalyst present.
- Apply Magnetic Field — the reactor's side magnet (right wall in this top-down view) pulls the ferromagnetic core of the nanocatalyst out of the liquid product, letting it be filtered and reused instead of discarded like a free (dissolved) enzyme. Recovery is never 100%: some particles are lost each cycle, and surviving ones lose a little activity to leaching and mechanical stress.
- Start Next Reaction Cycle — drains the current batch, refills with fresh oil/methanol, and reuses whatever nanocatalyst you recovered — watch the history chart's cumulative curve climb while per-cycle yield slowly decays.
- Drag the reactor view to pan, scroll/pinch to zoom — inspect individual particles near the magnet wall during recovery.
Real-world relevance: magnetically recoverable lipase-nanoparticle catalysts are an active biodiesel research direction because they combine a nanocatalyst's high reaction rate with a simple magnet-based separation step, avoiding the centrifugation or filtration costs of conventional immobilized-enzyme reactors.