Genome Mining Reveals Two Missing CrtP and AldH Enzymes in the C30 Carotenoid Biosynthesis Pathway in Planococcus faecalis AJ003T.

Planococcus faecalis AJ003T produces glycosyl-4,4'-diaponeurosporen-4'-ol-4-oic acid as its main carotenoid. Five carotenoid pathway genes were presumed to be present in the genome of P. faecalis AJ003T; however, 4,4-diaponeurosporene oxidase (CrtP) was non-functional, and a gene encoding aldehyde dehydrogenase (AldH) was not identified. In the present study, a genome mining approach identified two missing enzymes, CrtP2 and AldH2454, in the glycosyl-4,4'-diaponeurosporen-4'-ol-4-oic acid biosynthetic pathway. Moreover, CrtP2 and AldH enzymes were functional in heterologous Escherichia coli and generated two carotenoid aldehydes (4,4'-diapolycopene-dial and 4,4'-diaponeurosporene-4-al) and two carotenoid carboxylic acids (4,4'-diaponeurosporenoic acid and 4,4'-diapolycopenoic acid). Furthermore, the genes encoding CrtP2 and AldH2454 were located at a distance the carotenoid gene cluster of P. faecalis.