Studies on the “salvage” synthesis of ribonucleosides and their 5'-phosphates from nucleic acid bases by microorganisms were undertaken. After screening test of less than one hundred strains of type culture, it was found that inosine was produced from hypoxanthine by Arthrobacter ureafaciens, A. simplex, Flavobacterium aquatile and F. suaveolens.
In certain conditions, inosine was further oxidized and hydrolyzed into xanthosine, uric acid and etc.
As for the conditions of cultivation and reaction, the components of the medium and pH of the culture medium were important factors.
Using the standard method, the yield of inosine from hypoxanthine by F. suaveolens reached more than 6000, and the conversion was stoichiometric and any other by-products were not detected.
Inosine, xanthosine, guanosine and uridine were produced from adenine, xanthine, guanine and uracil, respectively, by F. suaveolens.