Genome mining of 2-phenylethanol biosynthetic genes from sp. CGMCC 5087 and heterologous overproduction in .

BACKGROUND

2-Phenylethanol (2-PE) is a higher aromatic alcohol that is widely used in the perfumery, cosmetics, and food industries and is also a potentially valuable next-generation biofuel. In our previous study, a new strain sp. CGMCC 5087 was isolated to produce 2-PE from glucose through the phenylpyruvate pathway.

RESULTS

In this study, candidate genes for 2-PE biosynthesis were identified from sp. CGMCC 5087 by draft whole-genome sequence, metabolic engineering, and shake flask fermentation. Subsequently, the identified genes encoding the 2-keto acid decarboxylase (Kdc) and alcohol dehydrogenase (Adh) enzymes from sp. CGMCC 5087 were introduced into BL21(DE3) to construct a high-efficiency microbial cell factory for 2-PE production using the prokaryotic phenylpyruvate pathway. The enzymes Kdc4427 and Adh4428 from sp. CGMCC 5087 showed higher performances than did the corresponding enzymes ARO10 and ADH2 from , respectively. The . cell factory was further improved by overexpressing two upstream shikimate pathway genes, and , to enhance the metabolic flux of the phenylpyruvate pathway, which resulted in 2-PE production of 260 mg/L. The combined overexpression of and increased the precursor supply of erythrose-4-phosphate and phosphoenolpyruvate, which resulted in 2-PE production of 320 mg/L, with a productivity of 13.3 mg/L/h.

CONCLUSIONS

The present study achieved the highest titer of de novo 2-PE production of in a recombinant system. This study describes a new, efficient 2-PE producer that lays foundation for the industrial-scale production of 2-PE and its derivatives in the future.