Gentamicin Formation in Micromonospora purpurea: Stimulatory Effect of Ammonium.

Abstract

The effect of ammoniumon the fermentative production of gentamicin in Micromonospora purpurea has been studied using a chemically defined medium. Ammoniumchloride concentrations ranging from 20 to 1 50 mMresulted in a proportional stimulation of growth and antibiotic formation. The use of other ammonium salts exerted a similar effect. Amongthe products of ammonium assimilation, glutamate and glutamine were able to exert the stimulatory effect. In addition, both amino acids reproduced the stimulation in resting cell systems of this microorganism and this result was not modified by the presence of chloramphenicol, eliminating a possible inductive action as the cause of this effect. The use of a glutamine synthetase inhibitor prevented antibiotic formation. This inhibition was reverted only by glutamine, suggesting that this amino acid was responsible of ammonium stimulation. Glutamine stimulation seems to be due to its ability to produce 2-deoxystreptamine and glucosamine, intermediates of the gentamicin biosynthetic pathway.

Gentamicin production by Micromonospora echinospora (Me‐ 22) in stirred tank reactor: effect of various parameters

“…Gonzalez et al [11] in his shake flask experiments showed the stimulatory effect of ammonium ion (nitrogen source) on the synthesis of gentamicin and reported that ammonium increases antibiotic formation through its conversion to glutamine. A similar effect of nitrogen has been reported for neomycin [12] and streptomycin [13] ) was attained in medium containing starch 10 g l -1 and soyabean meal 3 g l -1 at day 4, but production of gentamicin was less this might be due to high carbohydrate concentration.…”

Influence of Ammonium Salt and Fermentation pH on Acarbose Yield from <i>Streptomyces</i> M37

“…Similar conclusion was achieved in gentamicin and streptomycin biosynthesis. That is, glutamate, glutamine and glucosamine stimulated the formation of antibiotics containing aminoglycoside group [25]. Medium pH affects enzyme synthesis, enzymatic processes, and transport across cell membranes [7].…”

Strategies for Fermentation Medium Optimization: An In-Depth Review

“…The concentrations of the selected medium components were then changed over a desired range. Because of its ease and convenience, the OFAT has been the most preferred choice among the researchers for designing the medium composition and used in the initial stages in diverse fields (Gonzalez et al, 1995). This methodology is still in use even today, during the initial stages of medium formulation for the production of new metabolite or known compound from new source.…”