Production of Xanthosine-5′-Monophosphate and Inosine-5′-Monophosphate by Auxotrophic Mutants of a Coryneform Bacterium

Abstract

Production of xanthosine-5'-monophosphate and inosine-5'-monophosphate by auxotrophic mutants of a coryneform bacterium. Appl. Microbiol. 13:757-761. 1965-Although most microorganisms with genetic blocks in the purine nucleotide sequence excrete breakdown products, a coryneform bacterium was found to accumulate intact 5'-nucleotides in the extracellular medium. Adenineless mutants accumulated 0.4 to 0.6 g of inosine-5'-monophosphate per liter of broth. The yield of this nucleotide was increased to 0.8 to 0.9 g per liter when such mutants were mutated to xanthine dependence. Induction of a specific guanine requirement in adenineless auxotrophs resulted in cultures capable of producing high yields of xanthosine-5'-monophosphate (3 to 4 g per liter). Pure xanthosine-5'-monophosphate was isolated from broth by a procedure involving ion-exchange chromatography, charcoal adsorption, and barium precipitation.

Production of Guanosine-5′-Monophosphate and Inosine-5′-Monophosphate by Fermentation

“…The slant medium for temporary mai cultures has been described (3). Fresh prepared monthly and stored at 4 C. In dium was identical, except that agar was was prepared in 250-ml Erlenmeyer flas which contained 20 ml of medium.…”

“…Thiamine was included to reverse any possible toxicity of adenine. Fermentation conditions nodifications were the same as previously used (3). cribed below…”

“…Assays. The determination of ultraviolet-absorbing materials and the enzymatic assay for IMP were intenance of described by Demain et al (3). GMP was determined slants were by microbial assay with the use of the guanine-re-Loculum me-quiring mutant of Bacillus subtilis MB-1517.…”

“…It this assay for "total guanines" (4) measures all low sks, each of molecular weight guanine compounds, broths were first checked by paper chromatography to insure that production GMP was the only such compound present. In certain nucleotide, media used early in the investigation, guanine or escribed (3). guanosine predominated over GMP.…”

Strain improvement of industrially important microorganisms based on resistance to toxic metabolites and abiotic stress

“…This principle of decreasing the concentration of an inhibitory or repressive end product to bypass feedback inhibition or repression was best accomplished by the use of auxotrophic mutants. Indeed, auxotrophic mutation has been a major factor in the industrial production of primary products such as amino acids and nucleotides (Table ).…”