One such organism is Micrococcus luteus (American Type Culture Collection strain number ATCC 49442), which develops a yellow color due to production of riboflavin while growing on pyridine, but not when grown on other substrates, such as succinic acid. Laboratory synthesis
The first total synthesis of riboflavin was carried out by Richard Kuhns group. A substituted aniline, produced by reductive amination using D-ribose, was condensed with alloxan in the final step:

Uses
Treatment of corneal thinning
Keratoconus is the most common form of corneal ectasia, a progressive thinning of the cornea. The condition is treated by corneal collagen cross-linking, which increases corneal stiffness. Cross-linking is achieved by applying a topical riboflavin solution to the cornea, which is then exposed to ultraviolet A light. Migraine prevention
In its 2012 guidelines, the American Academy of Neurology stated that high-dose riboflavin (400 mg) is "probably effective and should be considered for migraine prevention," a recommendation also provided by the UK National Migraine Centre. A 2017 review reported that daily riboflavin taken at 400 mg per day for at least three months may reduce the frequency of migraine headaches in adults. Research on high-dose riboflavin for migraine prevention or treatment in children and adolescents is inconclusive, and so supplements are not recommended. Food coloring
Riboflavin is used as a food coloring (yellow-orange crystalline powder), and is designated with the E number, E101, in Europe for use as a food additive. Dietary recommendations
The National Academy of Medicine updated the Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for riboflavin in 1998.
Cellular fetal rhabdomyomas are composed of bland, primitive spindled cells. The spindle cells are haphazardly arranged primitive, elongated skeletal muscle cells. The cells are set within a well-developed fibromyxoid stroma. A different pattern (intermediate type) is predominantly composed of cells with better differentiation towards skeletal muscle. There are often large ganglion cell-like rhabdomyoblasts showing prominent nucleoli within nuclei that show vesicular chromatin distribution. Another population includes strap-like rhabdomyoblasts with darkly staining pink cytoplasm. Nearly all tumors show short to more sweeping fascicles of spindled rhabdomyoblasts. The tumor cells may infiltrate into adjacent skeletal muscle or fat. It is not uncommon to see peri-neural association, although not perineural infiltration. Diagnosis
These tumors may be detected prenatally by ultrasound and MRI. Additionally, preoperative fine needle aspiration can be used to diagnose the tumor. Ancillary testing
A phosphotungstic acid hematoxylin stain may be used to highlight cross striations in the cytoplasm of the tumor cells. PAS with diastase will highlight the presence of glycogen in the tumor cells cytoplasm. Immunohistochemistry will yield a positive reaction with a variety of myoid markers, including desmin, myoglobin, myogenin, MYOD1 and muscle specific actin. They may also be positive with vimentin, smooth muscle actin, and Leu-7. However, the tumor cells are almost always negative with glial fibrillary acidic protein, S100 protein, cytokeratin, epithelial membrane antigen, CD68, FLI1, CD99 and CD56. Although not used as frequently now, electron microscopy will show thick and thin myofilaments, Z-bands: these are features of sarcometric differentiation.