Anaerobic environment as an efficient approach to improve the photostability of fatty acid photodecarboxylase

Fatty acid photodecarboxylase of Chlorella variabilis NC64A(CvFAP) is a novel photoenzyme with great potential in the treatment of waste lipids and production of sustainable aviation fuel. However, the fragile nature of Cv FAP to blue light is an urgent challenge. Herein, we demonstrated anaerobic environment could significantly improve the photostability of Cv FAP for the first time. The decarboxylation of palmitic acid by Cv FAP for 3 h under anaerobic environment increased pentadecane yield by 44.7% as compared to that under aerobic environment. The residual activity of Cv FAP after blue-light preillumination in the absence of palmitic acid for 0.5 h under anaerobic environment was 80.4%, which was 258.7 times higher than that under aerobic environment. Remarkable accumulation of superoxide radical and singlet oxygen in Cv FAP under aerobic environment led to the poor photostability of Cv FAP. Anaerobic environment helped to mitigate the production of superoxide radical and singlet oxygen in Cv FAP, improving the photostability of Cv FAP.