Occurrence of cobalamin coenzymes in the photosynthetic green alga, Chlorella vulgaris

To analyze cobalamin metabolism in photosynthetic green algae, the effects of cobalamin on growth of Chorella vulgaris C-30 were studied and the algal cobalamin contents were assayed, Cobalamin significantly stimulated growth of the Chlorella cells, but biologically inactive cobalamin analogues did not, Chorella grown in a cobalamin-free medium (control) contained cobalamin coenzymes, 5'-deoxyadenosylcobalamin (7.95 +/- 0.31 ng/g wet weight) and methylcobalamin (2.72 +/- 0.45 ng/g wet weight), of which the levels were increased significantly in cobalamin-supplemented cells. These results indicate that the alga has ability to take up exogenous cobalamin and synthesize the coenzyme forms.