Photo-driven enzymatic decarboxylation of fatty acids for bio-aviation fuels production in a continuous microfluidic reactor

Fatty acid photodecarboxylase derived from Chlorella variabilis NC64A (CvFAP) is a novel enzyme that can convert fatty acids to corresponding C1-shortened alkanes under blue light illumination, which provides an alternative approach for the production of bio-aviation fuels under mild conditions. To date, the production of bio-aviation fuel using CvFAP is severely limited by an inefficient reactor. Microfluidic reactors have attracted significant attention owing to their high mass-transfer efficiency and low light attenuation in continuous photobiocatalysis. In this study, a microfluidic photobioreactor was proposed for the continuous photoenzymatic decarboxylation of palmitic acid for the first time. The optimal palmitic acid conversion of 96.7% was obtained at a flow rate of 10 μL/min, a blue light intensity of 200 μmol/(m2 s), a reaction temperature of 30 °C, a catalyst concentration of 2.4 mg/mL, a substrate concentration of 12 mM, and a cosolvent volume ratio of 30%. The maximum pentadecane production rate of 59.8 mM/h was achieved. The highest turnover frequency of CvFAP up to 19,186/h, as ever reported, was obtained at a flow rate of 40 μL/min. Meanwhile, the energy yield of 33.6 kJ/g and energy production rate of 533.5 kJ/L/h were achieved in continuous bio-aviation fuels production. Taken together, the continuous photoenzymatic decarboxylation of fatty acids in a microfluidic photobioreactor is a promising approach for bio-aviation fuels production.