Production of Biobased Ethylbenzene by Cascade Biocatalysis with an Engineered Photodecarboxylase

Abstract Production of commodity chemicals, such as benzene, toluene, ethylbenzene, and xylenes (BTEX), from renewable resources is key for a sustainable society. Biocatalysis enables one‐pot multistep transformation of bioresources under mild conditions, yet it is often limited to biochemicals. Herein, we developed a non‐natural three‐enzyme cascade for one‐pot conversion of biobased l ‐phenylalanine into ethylbenzene. The key rate‐limiting photodecarboxylase was subjected to structure‐guided semirational engineering, and a triple mutant CvFAP(Y466T/P460A/G462I) was obtained with a 6.3‐fold higher productivity. With this improved photodecarboxylase, an optimized two‐cell sequential process was developed to convert l ‐phenylalanine into ethylbenzene with 82 % conversion. The cascade reaction was integrated with fermentation to achieve the one‐pot bioproduction of ethylbenzene from biobased glycerol, demonstrating the potential of cascade biocatalysis plus enzyme engineering for the production of biobased commodity chemicals.