## 1 Introduction  
Macular pigment (MP) is found in the macular region of the primate retina, and consists mainly of lutein and zexanthin that cannot be synthesized by the body itself [1, 2]. Furthermore, the detection of lutein and zeaxanthin in the macular region of the retina can be used as the optical density of macular pigment (MPOD), which can be used as a biomarker to predict ophthalmic diseases and visual function [3]. Cataracts and age-related macular degeneration (AMD) are the leading causes of visual impairment and acquired blindness, affecting tens of millions of people worldwide to varying degrees. Although MP must be obtained from daily food, most people's daily intake is seriously insufficient. The latest research shows that daily intake of 10 mg lutein and 2 mg zeaxanthin can improve visual function and delay the development of AMD [4, 5]. Lutein can be provided to fetuses and infants through umbilical cord blood, breast milk, and diet. Lutein can accumulate in human oxidative stress and high metabolic organs, indicating that it plays a unique role in the development of human embryonic organs and the development of infant eyes and brain [6]. By investigating the changes in carotenoid content of pregnant women throughout pregnancy, it was determined that prenatal maternal lutein and zeaxanthin supplementation could offset maternal carotenoid consumption and improve maternal and infant physical fitness to a certain extent [7].  
Lutein and zeaxanthin are two of the 600 carotenoids in nature, which are deposited in the retina (macula) of the eye. They can be biosynthesis, which widely exists in egg yolk, corn, vegetables and fruits [8]. At present, there are many reports on eukaryotic biosynthesis of carotenoids. Their synthesis pathway has been clarified in orange-yellow fruits such as marigold flowers, mangoes, broccoli, watercress, and other green vegetables [9; 10; 11]. As far as production is concerned, the cultivation of marigold is a means of obtaining natural lutein and lutein esters. As far as microorganisms are concerned, free lutein can be biosynthesized by microalgae [9]. However, the production of lutein and zeaxanthin by prokaryotes was reported rarely.  
_Sphingomonas morindae_ sp. NBD5 was a new species that was identified as this genus. Phylogenetic analysis showed that it belonged to the Sphingomonadaceae family [12]. In our previous research, _Sphingomonas morindae_ sp. NBD5 had the function of producing lutein [13]. _Sphingopyxis_ sp. USTB-05 is a well-known strain that can be used to completely biodegradable cyanobacterium hepatotoxin [14], but whether it can produce lutein has not been investigated. Genomic studies of MP producing bacterial strains are rarely reported, and numerous genes encoding MP synthases need to be elucidated. Therefore, in order to fully elucidate the MP biosynthesis pathway in _Sphingomonas morindae_ sp. NBD5 and _Sphingopyxis_ sp. USTB-05, it is very important to discover the encoding genes and enzymes through genome mining. Here, we firstly sequenced the genome of _Sphingomonas morindae_ sp. NBD5, which was 4,239,716 bp and contained 3882 protein coding genes. Glucose converted to lutein or zeaxanthin pathways were discovered in _Sphingomonas morindae_ sp. NBD5 and _Sphingopyxis_ sp. USTB-05.