Photoenzymatic decarboxylation to produce renewable hydrocarbon fuels: A comparison between whole-cell and broken-cell biocatalysts

• We compared decarboxylation between Cv FAP BCs and Cv FAP@ E. coli for the first time. • Cv FAP BCs performed better than Cv FAP@ E. coli at rotation speed lower than 200 rpm. • Cv FAP BCs and Cv FAP@ E. coli showed identical performance at the optimal conditions. • Pentadecane yields for Cv FAP@ E. coli (88.4%) and Cv FAP BCs (95.4%) were obtained. • Highest conversion rate (17.2 mM/h) for Cv FAP BCs as ever reported was achieved. The recently discovered fatty acid photodecarboxylase from Chlorella variabilis NC64A ( Cv FAP) is a potential photoenzyme to produce sustainable aviation fuels from lipid-rich wastewater. Herein, we compared the catalytic performance in photoenzymatic decarboxylation reactions between recombinant Escherichia coli cells containing Cv FAP ( Cv FAP@ E. coli ) and broken cells ( Cv FAP BCs) prepared by supersonic treatment of Cv FAP@ E. coli under various catalytic conditions for the first time. The conversion of palmitic acid as a model substrate by Cv FAP BCs was 1.87 times higher than that by Cv FAP@ E. coli at a rotation speed of 100 rpm due to the absence of mass transfer resistance from the cytomembrane for Cv FAP BCs. However, no significant difference in the conversion of palmitic acid between Cv FAP@ E. coli (88.4%) and Cv FAP BCs (95.4%) was obtained under the optimal reaction conditions: a cell dry weight of 35.2 mg·mL −1 , a rotation speed of 200 rpm, a pH of 8.0, and a light intensity of 200 μmol·m −2 ·s −1 for 3 h. Good stabilities for Cv FAP BCs (92.4%) and Cv FAP@ E. coli (87.7%) were retained at 30 °C for 3 days. Cv FAP BCs was capable of decarboxylating palmitic acid at a high concentration of 54 mM with the highest conversion rate of 17.2 mM/h as previously reported. This work demonstrates the continuous potential of Cv FAP in producing hydrocarbon fuels.