**2. Bacterial Strains Producing Ketocarotenoids**

*Paracoccus* sp. strain N81106 (NBRC 101723), isolated from surface seawater near Aka island, Okinawa, Japan, was first shown to produce astaxanthin in bacteria [7,17]. This bacterium was also found to synthesize adonixanthin, adonixanthin Ά-D-glucoside, and astaxanthin Ά-D-glucoside [7,18]. *Paracoccus haeundaesis* BC74171T, isolated from the Haeundae Coast, Korea, was shown to produce astaxanthin mainly [19]. *Paracoccus marinus* KKL-A5T (NBRC 100637T), isolated from coastal seawater in Tokyo Bay, Japan, was found to produce adonixanthin diglucoside predominantly [20,21]. On the other hands, a marine bacterium *Brevundimona*s sp. strain SD212 (NBRC 101024) was revealed to synthesize not only astaxanthin and adonixanthin but also their 2(2ȝ)-hydroxylated metabolites, that is, 2-hydroxyastaxanthin ((2*R*,3*S*,3<sup>ȝ</sup>*S*)-2,3,3<sup>ȝ</sup>-trihydroxy-Ά,Ά-carotene-4,4<sup>ȝ</sup>-dione), 2-hydroxyadonixanthin ((2*R*,3*S*,3<sup>ȝ</sup>*R*)-2,3,3<sup>ȝ</sup>-trihydroxy-Ά,Ά-caroten-4-one), erythroxanthin ((3*S*,2<sup>ȝ</sup>*R*,3<sup>ȝ</sup>*R*)-3,2<sup>ȝ</sup>,3<sup>ȝ</sup>trihydroxy-Ά,Ά-caroten-4-one), 4-ketonostoxanthin ((2*R*,3*S*,2<sup>ȝ</sup>*R*,3<sup>ȝ</sup>*R*)-2,3,2<sup>ȝ</sup>,3<sup>ȝ</sup>tetrahydroxy-Ά,Ά-caroten-4-one) and 2,2ȝ-dyhydroxyastaxanthin ((2*<sup>R</sup>*,3*S*,2<sup>ȝ</sup>*R*,3<sup>ȝ</sup>*S*)- 2,3,2<sup>ȝ</sup>,3<sup>ȝ</sup>-tetrahydroxy-Ά,Ά-carotene-4,4<sup>ȝ</sup>-dione) [9]. Figure 1 shows the structures of the ketocarotenoids shown in this section and their feasible biosynthetic pathway. Figure 2 shows phylogenetic tree of the marine bacteria that produce astaxanthin and other ketocarotenoids, which were isolated in Marine biotechnology Institute (Kamaishi, Japan), along with the type strains relative to these bacteria, many of which are not marine bacteria but soil bacteria. Interestingly, the phylogenetically closest strains to the marine bacteria *Paracoccus* sp. N81106 and *Brevundimona*s sp. SD212 were soil bacteria *Paracoccus marcusii* DSM 11574T [22] and *Brevundimonas aurantiaca* ATCC 15266T, respectively (Figure 2). 
