Medium Components Essential for Guanosine Production in Bacillus subtilis MG-1

Abstract

Culture conditions for guanosine production were studied with Bacillus subtilis MG-1 that exclusively accumulated guanosine. Of components investigated, KH₂PO₄, KCl, Fe⁺⁺, Mn⁺⁺, NH₄NO₃ and sodium glutamate have played important roles for guanosine production. The optimal concentrations in the culture medium were 2.0g, 0.9g, 7.5mg, 7.5mg, 20.4g and 6.0g per liter, respectively.
In particular, the extremely minor concentration of Mn⁺⁺ 0.01ppm completely repressed guanosine production although the cells grew sufficiently. Amino acids mixture was neces-sary for cell growth, but not essential for guanosine production.
Under these conditions, MG-1 accumulated 15g of guanosine per liter in a weight yield of 18.8% of consumed sugar. However, a large amount of acetoin was also found as a bypro-duct.